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1.
Small ; 20(11): e2306690, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37926792

RESUMO

Non-aqueous solvents, in particular N,N-dimethylaniline (NMP), are widely applied for electrode fabrication since most sodium layered oxide cathode materials are readily damaged by water molecules. However, the expensive price and poisonousness of NMP unquestionably increase the cost of preparation and post-processing. Therefore, developing an intrinsically stable cathode material that can implement the water-soluble binder to fabricate an electrode is urgent. Herein, a stable nanosheet-like Mn-based cathode material is synthesized as a prototype to verify its practical applicability in sodium-ion batteries (SIBs). The as-prepared material displays excellent electrochemical performance and remarkable water stability, and it still maintains a satisfactory performance of 79.6% capacity retention after 500 cycles even after water treatment. The in situ X-ray diffraction (XRD) demonstrates that the synthesized material shows an absolute solid-solution reaction mechanism and near-zero-strain. Moreover, the electrochemical performance of the electrode fabricated with a water-soluble binder shows excellent long-cycling stability (67.9% capacity retention after 500 cycles). This work may offer new insights into the rational design of marvelous water stability cathode materials for practical SIBs.

2.
Angew Chem Int Ed Engl ; 63(18): e202401924, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38366134

RESUMO

Nitrate electroreduction reaction (eNO3 -RR) to ammonia (NH3) provides a promising strategy for nitrogen utilization, while achieving high selectivity and durability at an industrial scale has remained challenging. Herein, we demonstrated that the performance of eNO3 -RR could be significantly boosted by introducing two-dimensional Cu plates as electrocatalysts and eliminating the general carrier gas to construct a steady fluid field. The developed eNO3 -RR setup provided superior NH3 Faradaic efficiency (FE) of 99 %, exceptional long-term electrolysis for 120 h at 200 mA cm-2, and a record-high yield rate of 3.14 mmol cm-2 h-1. Furthermore, the proposed strategy was successfully extended to the Zn-nitrate battery system, providing a power density of 12.09 mW cm-2 and NH3 FE of 85.4 %, outperforming the state-of-the-art eNO3 -RR catalysts. Coupled with the COMSOL multiphysics simulations and in situ infrared spectroscopy, the main contributor for the high-efficiency NH3 production could be the steady fluid field to timely rejuvenate the electrocatalyst surface during the electrocatalysis.

3.
Angew Chem Int Ed Engl ; 62(44): e202313205, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37721200

RESUMO

Enamides, functional derivatives of enamines, play a significant role as synthetic targets. However, the stereoselective synthesis of these molecules has posed a longstanding challenge in organic chemistry, particularly for acyclic enamides that are less thermodynamically stable. In this study, we present a general strategy for constructing ß-borylenamides by C-H borylation, which provides a versatile platform for generating the stereodefined enamides. Our approach involves the utilization of metalloid borenium cation, generated through the reaction of BBr3 and enamides in the presence of two different additives, avoiding any exogenous catalyst. Importantly, the stereoconvergent nature of this methodology allows for the use of starting materials with mixed E/Z configurations, thus highlighting the unique advantage of this chemistry. Mechanistic investigations have shed light on the pivotal roles played by the two additives, the reactive boron species, and the phenomenon of stereoconvergence.

4.
Angew Chem Int Ed Engl ; 61(39): e202207252, 2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-35819244

RESUMO

Rather than just focusing on the catalyst itself in the electrocatalytic CO2 reduction reaction (eCO2 RR), as previously reviewed elsewhere, we herein extend the discussion to the special topic of the microenvironment around the electrocatalytic center and present a comprehensive overview of recent research progress. We categorize the microenvironment based on the components relevant to electrocatalytic active sites, i.e., the catalyst surface, substrate, co-reactants, electrolyte, membrane, and reactor. Supported by most of the reported articles, the relevant factors affecting the catalytic performance of eCO2 RR are then discussed in detail, and existing challenges and potential solutions are mentioned. Perspectives for the future research on eCO2 RR, including the integration of different microenvironment factors, the extension to industrial application by coupling with carbon capture and conversion, and separation of products, are also discussed.

5.
Angew Chem Int Ed Engl ; 60(15): 8500-8504, 2021 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-33449421

RESUMO

Robust strategies to enable the rapid construction of complex organoboronates in selective, practical, low-cost, and environmentally friendly modes remain conspicuously underdeveloped. Here, we develop a general strategy for the site-selective C-H borylation of pyrroles by using only BBr3 directed by pivaloyl groups, avoiding the use of any metal. The site-selectivity is generally dominated by chelation and electronic effects, thus forming diverse C2-borylated pyrroles against the steric effect. The formed products can readily engage in downstream transformations, enabling a step-economic process to access drugs such as Lipitor. DFT calculations (wB97X-D) demonstrate the preferred positional selectivity of this reaction.

6.
Adv Synth Catal ; 362(1): 242-247, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-34084099

RESUMO

Photoredox-mediated radical/polar crossover (RPC) processes provide unique solutions to challenging annulations. Herein, we describe an approach to the cyclopropanation of olefins that are embedded within bicyclic scaffolds. Whereas these systems are notoriously recalcitrant toward classical cyclopropanation approaches, RPC cyclopropanation can be executed with ease, leading to polycarbocyclic and polyheterocyclic cyclopropanes. The cyclopropanation proceeds through a photoredox-enabled Giese-type radical addition followed by an intramolecular anionic substitution reaction on a neopentyl leaving group.

7.
Int J Ment Health Nurs ; 33(4): 1026-1036, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38379368

RESUMO

Marital concerns can trigger emotional stress, especially among long-term hospitalised individuals diagnosed with schizophrenia, significantly affecting their treatment and recovery. Unfortunately, rehabilitation programs tend to overlook the marital needs of individuals with diagnosed schizophrenia. This research aimed to investigate the content related to marital concerns of Chinese individuals diagnosed with schizophrenia who were undergoing extended hospitalisation. Fifteen participants diagnosed with schizophrenia were recruited through purposive sampling for face-to-face semi-structured interviews. The gathered data were analysed using Colaizzi's method, revealing three themes: (1) manifestations of marriage-related concerns, (2) effects of marriage on disease progression, and (3) the need for support from family and the hospital. This study offers new insights into marital concerns among long-term schizophrenia inpatients and underscores the significance of screening and intervention for such concerns. Healthcare professionals and family members should extend support to patients to foster confidence within their marital relationships.


Assuntos
Hospitalização , Casamento , Esquizofrenia , Humanos , Feminino , Masculino , Esquizofrenia/terapia , Adulto , Pessoa de Meia-Idade , Casamento/psicologia , Entrevistas como Assunto , Psicologia do Esquizofrênico , Progressão da Doença
8.
Talanta ; 282: 127030, 2024 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-39406095

RESUMO

Nanoplastics are prevalent in the environment and emerging evidence suggests they can induce organ injury by activating oxidative stress. Given that both nanoplastics and Zn2+ levels are intertwined with oxidative stress, it is crucial to investigate the influence of nanoplastics on the level of labile Zn2+ and get a better understanding of their cytotoxicity mechanisms. At the organelle level, the Golgi apparatus plays an active role in stress responses. In this study, we synthesized Golgi-Zn, the first ratiometric fluorescence nanosensor with Golgi apparatus targeting ability for monitoring of Zn2+. This nanosensor demonstrated high sensitivity and selectivity as well as robust pH stability for Zn2+ sensing. The ratio of the two fluorescence signals of Golgi-Zn showed a good linearity with Zn2+ concentration in the range of 0.5-10 µM, achieving a limit of detection of ∼72.4 nM. Furthermore, the nanosensor exhibited low cytotoxicity and effectively targeted the Golgi apparatus. Leveraging these fascinating features, we successfully applied Golgi-Zn for visualizing exogenous and endogenous Zn2+ levels in the Golgi apparatus. Moreover, with the help of Golgi-Zn, we found that nanoplastics stimulation could increase the level of Zn2+ in the Golgi apparatus.

9.
Ying Yong Sheng Tai Xue Bao ; 35(6): 1695-1704, 2024 Jun.
Artigo em Zh | MEDLINE | ID: mdl-39235029

RESUMO

Ant nests can affect the process and seasonal dynamics of forest soil methane emissions through mediating methane oxidation/reduction microorganisms and physicochemical environments. To explore the process and mechanism by which ant nests affect soil methane emissions from Hevea brasiliensis plantation in Xishuangbanna, we measured the seasonal dynamics of methane emissions from ant nest and non-nest soils by using static chamber-gas chromatography method, and analyzed the effect of ant nesting on the changes in functional microbial diversity, microhabitats, and soil nutrients in the plantations. The results showed that: 1) Ant nests significantly affected the mean annual soil methane emissions in tropical plantation. Methane emissions in ant nest were decreased by 59.9% than the non-nest soil. In the dry season, ant nest soil was a methane sink (-1.770 µg·m-2·h-1), which decreased by 87.2% compared with the non-nest soil, while it was a methane source (0.703 µg·m-2·h-1) that increased by 152.7% in the wet season. 2) Ant nesting affected methane emissions via changing soil temperature, humidity, carbon and nitrogen concentrations. In contrast to the control, the mean annual temperature, humidity, and carbon and nitrogen content increased by 4.9%-138.5% in ant nest soils, which explained 90.1%, 97.3%, 27.3%-90.0% of the variation in methane emissions, respectively. 3) Ant nesting affected the emission dynamics through changing the diversity and community structure of methane functional microbe. Compared with the control, the average annual methanogen diversity (Ace, Chao1, Shannon, and Simpson indices) in the ant nest ranged from -9.9% to 61.2%, which were higher than those (-8.7%-31.2%) of the methane-oxidising bacterial communities. The relative abundance fluctuations of methanogens and methanotrophic bacteria were 46.76% and -6.33%, respectively. The explaining rate of methanogen diversity to methane emissions (78.4%) was higher than that of oxidizing bacterial diversity (54.5%), the relative abundance explained by the dominant genus of methanogens was 68.9%. 4) The structural equation model showed that methanogen diversity, methanotroph diversity, and soil moisture were the main factors controlling methane emissions, contributing 95.6%, 95.0%, and 91.2% to the variations of emissions, respectively. The contribution (73.1%-87.7%) of soil temperature and carbon and nitrogen components to the emission dynamics was ranked the second. Our results suggest that ant nesting mediates the seasonal dynamics of soil methane emissions, primarily through changing the diversity of methane-function microorganisms and soil water conditions. The research results deepen the understanding of the mechanism of biological regulation of methane emission in tropical forest soil.


Assuntos
Formigas , Florestas , Metano , Comportamento de Nidação , Estações do Ano , Solo , Clima Tropical , Metano/análise , Metano/metabolismo , Formigas/fisiologia , Solo/química , Animais , China , Microbiologia do Solo , Hevea/crescimento & desenvolvimento
10.
Ying Yong Sheng Tai Xue Bao ; 35(3): 678-686, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38646755

RESUMO

Exploring the effects of ant nests on soil CH4 emissions in the secondary tropical forests is of great scientific significance to understand the contribution of soil faunal activities to greenhouse gas emissions. With static chamber-gas chromatography method, we measured the dry-wet seasonal dynamics of CH4 emissions from ant nests and control soils in the secondary forest of Syzygium oblatum communities in Xishuangbanna. We also examined the linkages of ant-mediated changes in functional microbial diversity and soil physicochemical properties with CH4 emissions. The results showed that: 1) Ant nests significantly accelerated soil CH4 emissions, with average CH4 emissions in the ant nests being 2.6-fold of that in the control soils. 2) The CH4 emissions had significant dry-wet seasonal variations, which was a carbon sink in the dry seasons (from -0.29±0.03 to -0.53±0.02 µg·m-2·h-1) and a carbon source in the wet seasons (from 0.098±0.02 to 0.041±0.009 µg·m-2·h-1). The CH4 emissions were significantly higher in ant nests than in control soils. The CH4 emissions from the ant nests had smaller dry-wet seasonal variation (from -0.38±0.01 to 0.12±0.02 µg·m-2·h-1) than those in the control soils (from -0.65±0.04 to 0.058±0.006 µg·m-2·h-1). 3) Ant nests significantly increased the values (6.2%-37.8%) of soil methanogen diversity (i.e., Ace and Shannon indices), temperature and humidity, carbon pools (i.e., total, easily oxidizable, and microbial carbon), and nitrogen pools (i.e., total, hydrolyzed, ammonium, and microbial biomass nitrogen), but decreased the diversity (i.e., Ace and Chao1 indices) of methane-oxidizing bacteria by 21.9%-23.8%. 4) Results of the structural equation modeling showed that CH4 emissions were promoted by soil methanogen diversity, temperature and humidity, and C and N pools, but inhibited by soil methane-oxidizing bacterial diversity. The explained extents of soil temperature, humidity, carbon pool, nitrogen pool, methanogen diversity, and methane-oxidizing bacterial diversity for the CH4 emission changes were 6.9%, 21.6%, 18.4%, 15.2%, 14.0%, and 10.8%, respectively. Therefore, ant nests regulated soil CH4 emission dynamics through altering soil functional bacterial diversities, micro-habitat, and carbon and nitrogen pools in the secondary tropical forests.


Assuntos
Formigas , Florestas , Metano , Solo , Clima Tropical , Metano/análise , Metano/metabolismo , Animais , Solo/química , China , Microbiologia do Solo , Estações do Ano
11.
Adv Mater ; 36(28): e2312566, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38630368

RESUMO

Transition metal oxides (TMOs) are widely studied for loading of various catalysts due to their low cost and high structure flexibility. However, the prevailing close-packed nature of most TMOs crystals has restricted the available loading sites to surface only, while their internal bulk lattice remains unactuated due to the inaccessible narrow space that blocks out most key reactants and/or particulate catalysts. Herein, using tunnel-structured MnO2, this study demonstrates how TMO's internal lattice space can be activated as extra loading sites for atomic Ag in addition to the conventional surface-only loading, via which a dual-form Ag catalyst within MnO2 skeleton is established. In this design, not only faceted Ag nanoparticles are confined onto MnO2 surface by coherent lattice-sharing, Ag atomic strings are also seeded deep into the sub-nanoscale MnO2 tunnel lattice, enriching the catalytically active sites. Tested for electrochemical CO2 reduction reaction (eCO2RR), such dual-form catalyst exhibits a high Faradaic efficiency (94%), yield (67.3 mol g-1 h-1) and durability (≈48 h) for CO production, exceeding commercial Ag nanoparticles and most Ag-based electrocatalysts. Theoretical calculations further reveal the concurrent effect of such dual-form catalyst featuring facet-dependent eCO2RR for Ag nanoparticles and lattice-confined eCO2RR for Ag atomic strings, inspiring the future design of catalyst-substrate configuration.

12.
Int J Neurosci ; 123(6): 433-8, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23286382

RESUMO

The purpose of this report is to inform medical professionals of a case in which brachiocephalic vein thrombosis caused a transient ischemic attack (TIA). A brain computerized tomography (CT) scan, magnetic resonance imaging, digital subtraction angiography, head and lung CT angiography, jugular venography, cardiac color Doppler ultrasound scan, color Doppler ultrasound scan of the neck and lower vascular extremities and 24-hour, continuous electrocardiogram monitoring were performed. A 50-year-old male experienced a total of 31 onsets of weakness in the right side of his body, speech impairment and numbness in the right side of his body during a period of 20 days. Imaging results did not reveal evidence of a cerebral infarction. The potential of a TIA with an arterial origin and other causes were ruled out, and a left brachiocephalic vein thrombosis and left jugular vein congestion were discovered. Thus, the brachiocephalic vein thrombosis was considered to be the cause of the TIA. The patient received anticoagulant and antiplatelet aggregation treatment. On the following day after the termination of the TIA, a color Doppler ultrasound scan detected the opening of the jugular venous arch, but the blood flow that returned to the superior vena cava via the left brachiocephalic vein did not significantly increase. A brachiocephalic vein thrombosis can be the cause of a TIA. In addition to the anticoagulant and antiplatelet aggregation treatment, the opening of the collateral of veins, including that of the jugular venous arch, may play an important role in reducing venous congestion and in terminating TIAs.


Assuntos
Veias Braquiocefálicas/patologia , Ataque Isquêmico Transitório/etiologia , Trombose Venosa/complicações , Diagnóstico Diferencial , Humanos , Ataque Isquêmico Transitório/complicações , Ataque Isquêmico Transitório/diagnóstico , Ataque Isquêmico Transitório/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Radiografia , Ultrassonografia , Trombose Venosa/diagnóstico por imagem
13.
Int J Neurosci ; 123(5): 347-52, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23240577

RESUMO

Due to the hidden hemorrhage and a lack of specificity in its manifestations, perirenal hemorrhage as a complication of interventional radiology procedures is not always diagnosed in a timely manner; furthermore, the cause of hemorrhage is often misidentified or uncertain. In this report, two cases of elderly male patients who each had a perirenal hemorrhage on the same side after an interventional radiology operation against head and neck vessels by the same operator on the same day are described. This study demonstrated that the perirenal hemorrhages in both patients were related to the interventional radiology operations, providing a reminder that operating gently and always keeping the guide wire in sight during the insertion are critical for reducing the incidence rate of perirenal hemorrhage.


Assuntos
Perda Sanguínea Cirúrgica , Nefropatias/diagnóstico por imagem , Nefropatias/etiologia , Radiografia Intervencionista/efeitos adversos , Idoso , Perda Sanguínea Cirúrgica/prevenção & controle , Humanos , Masculino , Pessoa de Meia-Idade , Ultrassonografia
14.
Small Methods ; : e2301307, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38088567

RESUMO

Despite that extensive efforts have been dedicated to the search for advanced catalysts to boost the electrocatalytic nitrobenzene reduction reaction (eNBRR), its progress is severely hampered by the limited understanding of the relationship between catalyst structure and its catalytic performance. Herein, this review aims to bridge such a gap by first analyzing the eNBRR pathway to present the main influential factors, such as electrolyte feature, applied potential, and catalyst structure. Then, the recent advancements in catalyst design for eNBRR are comprehensively summarized, particularly about the impacts of chemical composition, morphology, and crystal facets on regulating the local microenvironment, electron and mass transport for boosting catalytic performance. Finally, the future research of eNBRR is also proposed from the perspectives of performance enhancement, expansion of product scope, in-depth understanding of the reaction mechanism, and acceleration of the industrialization process through the integration of upstream and downstream technologies.

15.
Adv Mater ; 35(52): e2310433, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37931017

RESUMO

The value-added chemicals, monoxide, methane, ethylene, ethanol, ethane, and so on, can be efficiently generated through the electrochemical CO2 reduction reaction (eCO2 RR) when equipped with suitable catalysts. Among them, ethylene is particularly important as a chemical feedstock for petrochemical manufacture. However, despite its high Faradaic efficiency achievable at relatively low current densities, the substantial enhancement of ethylene selectivity and stability at industrial current densities poses a formidable challenge. To facilitate the industrial implementation of eCO2 RR for ethylene production, it is imperative to identify key strategies and potential solutions through comprehending the recent advancements, remaining challenges, and future directions. Herein, the latest and innovative catalyst design strategies of eCO2 RR to ethylene are summarized and discussed, starting with the properties of catalysts such as morphology, crystalline, oxidation state, defect, composition, and surface engineering. The review subsequently outlines the related important state-of-the-art technologies that are essential in driving forward eCO2 RR to ethylene into practical applications, such as CO2 capture, product separation, and downstream reactions. Finally, a greenhouse model that integrates CO2 capture, conversion, storage, and utilization is proposed to present an ideal perspective direction of eCO2 RR to ethylene.

16.
Ying Yong Sheng Tai Xue Bao ; 34(5): 1218-1224, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37236938

RESUMO

We assessed the seasonal dynamics of N2O emission in ant nests soils in secondary tropical Millettia leptobotrya forest of Xishuangbanna by using the static chamber-gas chromatography method, and determined the lin-kages between ant-mediated changes in soil properties (e.g., carbon pool, nitrogen pool, and temperature and humidity) and N2O emission. The results showed that ant nesting significantly affected soil N2O emission. The ave-rage soil N2O emission (0.67 mg·m-2·h-1) in ant nests was 40.2% higher than that in the control (0.48 mg·m-2·h-1). N2O emission in ant nests and the control showed substantial seasonal variation, with higher rate in June (0.90 and 0.83 mg·m-2·h-1, respectively) than that in March (0.38 and 0.19 mg·m-2·h-1, respectively). Ant nesting significantly increased the values (7.1%-74.1%) of moisture, temperature, organic carbon, total nitrogen, hydrolytic nitrogen, ammonium nitrogen, nitrate nitrogen, and microbial biomass carbon, but decreased pH (9.9%) compared with the control. Results of structural equation model showed that soil N2O emission was promoted by soil C and N pool, temperature, and humidity, but was inhibited by soil pH. The explained extents of soil nitrogen pool, carbon pool, temperature and humidity, and pH for N2O emission changes were 37.2%, 27.7%, 22.9% and 9.4%, respectively. Therefore, ant nesting regulated N2O emission dynamics by changing nitrification and denitrification substrates (e.g., nitrate and ammoniacal nitrogen), carbon pool, and micro-habitat (temperature and moisture) of soil in the secondary tropical forest.


Assuntos
Formigas , Solo , Animais , Solo/química , Nitratos/análise , Estações do Ano , Florestas , Nitrogênio/análise , Carbono , Óxido Nitroso/análise
17.
Eur J Clin Pharmacol ; 68(2): 131-9, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21837395

RESUMO

PURPOSE: Cerebral vasospasm (CVS) is a frequent and unpredictable complication in patients with subarachnoid hemorrhage (SAH) and often leads to poor outcomes. This study was aimed at evaluating the efficacy and safety of fasudil in the treatment of CVS in patients with SAH. METHODS: A search was conducted using the full-text database of Chinese scientific journals, the Wanfang Database (January 1999 to November 2010), the Chinese Medical Association Digital Journal Database, PubMed, the Cochrane library, OVID, and EMBase (searching through November 2010). RESULTS: A total of 8 studies met the inclusion criteria. The incidence rates of symptomatic CVS and CVS confirmed by angiography among the patients in the fasudil group were only 48% (odds ratio [OR] = 0.48, 95% confidence interval [CI]: 0.32-0.72, P = 0.0005) and 40% (OR = 0.40, 95% CI: 0.24-0-67, P = 0.0004) respectively of that of the control group. The odds ratios of cerebral infarction for all cases and cerebral infarction for CVS cases in the fasudil group were only 50% (OR = 0.50, 95% CI: 0.34-0.76, P = 0.0009) and 43% (OR = 0.43, 95% CI: 0.26-0.70, P = 0.0008) respectively of that of the control group. CONCLUSIONS: Fasudil greatly reduces the occurrence of CVS and cerebral infarction in SAH patients, significantly improves the clinical outcomes of the patients (as assessed by the Glasgow Outcome Scale). Because of the limited number of trials and samples available for analysis, the conclusions from the present study still need to be validated with results from large randomized, controlled clinical trials.


Assuntos
1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/análogos & derivados , Infarto Cerebral/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Hemorragia Subaracnóidea/tratamento farmacológico , Vasoespasmo Intracraniano/tratamento farmacológico , Quinases Associadas a rho/antagonistas & inibidores , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/uso terapêutico , Adulto , Humanos , Pessoa de Meia-Idade , Resultado do Tratamento
18.
Nat Commun ; 12(1): 4526, 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34312381

RESUMO

Sulfonium salts bearing a positively charged sulfur atom with three organic substituents have intrigued chemists for more than a century for their unusual structures and high chemical reactivity. These compounds are known to undergo facile single-electron reduction to emerge as a valuable and alternative source of aryl radicals for organic synthesis. However, the generation of non-stabilized alkyl radicals from sulfonium salts has been a challenge for several decades. Here we report the treatment of S-(alkyl) thianthrenium salts to generate non-stabilized alkyl radicals as key intermediates granting the controlled and selective outcome of the ensuing reactions under mild photoredox conditions. The value of these reagents has been demonstrated through the efficient construction of alkylboronates and other transformations, including heteroarylation, alkylation, alkenylation, and alkynylation. The developed method is practical, and provides the opportunity to convert C-OH bond to C-B and C-C bonds.

19.
Sci Adv ; 6(51)2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33328235

RESUMO

The first development of an external oxidant-compatible system involving a phosphorus(III)-directed C-H functionalization has been uncovered. An efficient C-H esterification of indoles with CO and alcohols has been reported in which the high reactivity and the exclusive C7-selectivity derives from the selection of a P(III)-directing group and the utilization of benzoquinone as an external oxidant with palladium catalysis. This strategy shows many advantages, involving an easily accessible and removable directing group, the use of cheap carbonylation sources, a broad substrate scope, and excellent positional selectivity. Two cyclopalladated intermediates were confirmed by x-ray analysis, uncovering key mechanistic features of this P(III)-directed C-H metalation event.

20.
Chin Med J (Engl) ; 133(10): 1182-1191, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32433050

RESUMO

BACKGROUND: Atrial natriuretic peptide (ANP) and its natriuretic peptide receptors A (NPR-A) and C (NPR-C) are involved in the regulation of physiological and pathophysiological process of blood pressure. The present study aimed to determine the role of NPR-C in the development of salt-sensitive hypertension. METHODS: The Dahl salt-sensitive (DS) and salt-resistant (DR) rats were used in this study. Animals were matched according to their age and weight, and then placed on either a high-salt (HS, 8%) or a normal-salt (NS, 0.4%) diet for 6 weeks randomly using random number table. The systolic blood pressure (SBP), plasmatic sodium concentration (PLNa), urinary sodium excretion (UVNa), and serum creatinine concentration (Scr) were measured. The concentration of ANP in blood and tissues (heart and kidney) was detected by enzyme-linked immunosorbent assay. The expression of ANP, NPR-A, and NPR-C in kidney was evaluated with western blot analysis. Regarding renal redox state, the concentration changes in malondialdehyde (MDA), lipofuscin, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox), and nitric oxide synthase (NOS) in kidney were detected by a spectrophotometric method. The kidney damage was evaluated using pathological techniques and the succinodehydrogenase (SDHase) examination. Furthermore, after an intra-peritoneal injection of C-atrial natriuretic peptide (ANP)4-23 (C-ANP4-23), an NPR-C receptor agonist, the SBP, biochemical values in blood and urine, and renal redox state were evaluated. The paired Student's t test and analysis of variance followed by the Bonferroni test were performed for statistical analyses of the comparisons between two groups and multiple groups, respectively. RESULTS: The baseline SBP in all groups was within the normal range. At the end of the 6-week experiment, HS diet significantly increased the SBP in DS rats from 116.63 ±â€Š2.90 mmHg to 162.25 ±â€Š2.15 mmHg (t = -10.213, P < 0.001). The changes of SBP were not significant in DS rats on an NS diet and DR rats on an NS diet or on an HS diet (all P > 0.05). The significant increase of PLNa, UVNa, and Scr related to an HS diet was found in both DS and DR rats (all P < 0.05). However, significant changes in the concentration (t = -21.915, P < 0.001) and expression of renal ANP (t = -3.566, P = 0.016) and the expression of renal NPR-C (t = 5.864, P = 0.002) were only observed in DS hypertensive rats. The significantly higher desmin immunochemical staining score (t = -5.715, P = 0.005) and mitochondrial injury score (t = -6.325, P = 0.003) accompanied by the lower SDHase concentration (t = 3.972, P = 0.017) revealed mitochondrial pathologic abnormalities in podocytes in DS rats with an HS diet. The distinct increases of MDA (t = -4.685, P = 0.009), lipofuscin (t = -8.195, P = 0.001), and Nox (t = -12.733, P < 0.001) but not NOS (t = -0.328, P = 0.764) in kidneys were also found in DS hypertensive rats. C-ANP4-23 treatment significantly decreased the SBP induced by HS in DS rats (P < 0.05), which was still higher than NS groups with the vehicle or C-ANP4-23 treatment (P < 0.05). Moreover, the HS-induced increase of MDA, lipofuscin, Nox concentrations, and Nox4 expression in DS rats was significantly attenuated by C-ANP4-23 treatment as compared with those with HS diet and vehicle injection (all P < 0.05). CONCLUSIONS: The results indicated that the renal NPR-C might be involved in the salt-sensitive hypertension through the damage of mitochondria in podocytes and the reduction of the anti-oxidative function. Hence, C-ANP4-23 might serve as a therapeutic agent in treating salt-sensitive hypertension.


Assuntos
Hipertensão , Podócitos , Animais , Pressão Sanguínea , Hipertensão/metabolismo , Rim/metabolismo , Oxirredução , Ratos , Ratos Endogâmicos Dahl
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