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1.
Nature ; 619(7970): 514-520, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37407819

RESUMO

Frustrated Lewis pairs (FLPs) are well documented for the activation of small molecules such as dihydrogen and carbon dioxide1-4. Although canonical FLP chemistry is heterolytic in nature, recent work has shown that certain FLPs can undergo single-electron transfer to afford radical pairs5. Owing to steric encumbrance and/or weak bonding association, these radicals do not annihilate one another, and they have thus been named frustrated radical pairs (FRPs). Notable preliminary results suggest that FRPs may be useful reagents in chemical synthesis6-8, although their applications remain limited. Here we demonstrate that the functionalization of C(sp3)-H bonds can be accomplished using a class of FRPs generated from disilazide donors and an N-oxoammonium acceptor. Together, these species undergo single-electron transfer to generate a transient and persistent radical pair capable of cleaving unactivated C-H bonds to furnish aminoxylated products. By tuning the structure of the donor, it is possible to control regioselectivity and tailor reactivity towards tertiary, secondary or primary C-H bonds. Mechanistic studies lend strong support for the formation and involvement of radical pairs in the target reaction.

2.
Nature ; 615(7950): 67-72, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36603811

RESUMO

Pyridines and related N-heteroarenes are commonly found in pharmaceuticals, agrochemicals and other biologically active compounds1,2. Site-selective C-H functionalization would provide a direct way of making these medicinally active products3-5. For example, nicotinic acid derivatives could be made by C-H carboxylation, but this remains an elusive transformation6-8. Here we describe the development of an electrochemical strategy for the direct carboxylation of pyridines using CO2. The choice of the electrolysis setup gives rise to divergent site selectivity: a divided electrochemical cell leads to C5 carboxylation, whereas an undivided cell promotes C4 carboxylation. The undivided-cell reaction is proposed to operate through a paired-electrolysis mechanism9,10, in which both cathodic and anodic events play critical roles in altering the site selectivity. Specifically, anodically generated iodine preferentially reacts with a key radical anion intermediate in the C4-carboxylation pathway through hydrogen-atom transfer, thus diverting the reaction selectivity by means of the Curtin-Hammett principle11. The scope of the transformation was expanded to a wide range of N-heteroarenes, including bipyridines and terpyridines, pyrimidines, pyrazines and quinolines.


Assuntos
Dióxido de Carbono , Eletroquímica , Pirazinas , Piridinas , Pirimidinas , Quinolinas , Hidrogênio/química , Pirazinas/química , Piridinas/química , Pirimidinas/química , Eletroquímica/métodos , Dióxido de Carbono/química , Quinolinas/química , Preparações Farmacêuticas/síntese química , Preparações Farmacêuticas/química
3.
Nature ; 615(7954): 830-835, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36922588

RESUMO

Perovskite light-emitting diodes (LEDs) have attracted broad attention due to their rapidly increasing external quantum efficiencies (EQEs)1-15. However, most high EQEs of perovskite LEDs are reported at low current densities (<1 mA cm-2) and low brightness. Decrease in efficiency and rapid degradation at high brightness inhibit their practical applications. Here, we demonstrate perovskite LEDs with exceptional performance at high brightness, achieved by the introduction of a multifunctional molecule that simultaneously removes non-radiative regions in the perovskite films and suppresses luminescence quenching of perovskites at the interface with charge-transport layers. The resulting LEDs emit near-infrared light at 800 nm, show a peak EQE of 23.8% at 33 mA cm-2 and retain EQEs more than 10% at high current densities of up to 1,000 mA cm-2. In pulsed operation, they retain EQE of 16% at an ultrahigh current density of 4,000 mA cm-2, along with a high radiance of more than 3,200 W s-1 m-2. Notably, an operational half-lifetime of 32 h at an initial radiance of 107 W s-1 m-2 has been achieved, representing the best stability for perovskite LEDs having EQEs exceeding 20% at high brightness levels. The demonstration of efficient and stable perovskite LEDs at high brightness is an important step towards commercialization and opens up new opportunities beyond conventional LED technologies, such as perovskite electrically pumped lasers.

4.
Nature ; 604(7905): 292-297, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35189623

RESUMO

Recent research in medicinal chemistry has suggested that there is a correlation between an increase in the fraction of sp3 carbons-those bonded to four other atoms-in drug candidates and their improved success rate in clinical trials1. As such, the development of robust and selective methods for the construction of carbon(sp3)-carbon(sp3) bonds remains a critical problem in modern organic chemistry2. Owing to the broad availability of alkyl halides, their direct cross-coupling-commonly known as cross-electrophile coupling-provides a promising route towards this objective3-5. Such transformations circumvent the preparation of carbon nucleophiles used in traditional cross-coupling reactions, as well as stability and functional-group-tolerance issues that are usually associated with these reagents. However, achieving high selectivity in carbon(sp3)-carbon(sp3) cross-electrophile coupling remains a largely unmet challenge. Here we use electrochemistry to achieve the differential activation of alkyl halides by exploiting their disparate electronic and steric properties. Specifically, the selective cathodic reduction of a more substituted alkyl halide gives rise to a carbanion, which undergoes preferential coupling with a less substituted alkyl halide via bimolecular nucleophilic substitution to forge a new carbon-carbon bond. This protocol enables efficient cross-electrophile coupling of a variety of functionalized and unactivated alkyl electrophiles in the absence of a transition metal catalyst, and shows improved chemoselectivity compared with existing methods.

5.
Nature ; 591(7850): 413-419, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33618348

RESUMO

The deep population history of East Asia remains poorly understood owing to a lack of ancient DNA data and sparse sampling of present-day people1,2. Here we report genome-wide data from 166 East Asian individuals dating to between 6000 BC and AD 1000 and 46 present-day groups. Hunter-gatherers from Japan, the Amur River Basin, and people of Neolithic and Iron Age Taiwan and the Tibetan Plateau are linked by a deeply splitting lineage that probably reflects a coastal migration during the Late Pleistocene epoch. We also follow expansions during the subsequent Holocene epoch from four regions. First, hunter-gatherers from Mongolia and the Amur River Basin have ancestry shared by individuals who speak Mongolic and Tungusic languages, but do not carry ancestry characteristic of farmers from the West Liao River region (around 3000 BC), which contradicts theories that the expansion of these farmers spread the Mongolic and Tungusic proto-languages. Second, farmers from the Yellow River Basin (around 3000 BC) probably spread Sino-Tibetan languages, as their ancestry dispersed both to Tibet-where it forms approximately 84% of the gene pool in some groups-and to the Central Plain, where it has contributed around 59-84% to modern Han Chinese groups. Third, people from Taiwan from around 1300 BC to AD 800 derived approximately 75% of their ancestry from a lineage that is widespread in modern individuals who speak Austronesian, Tai-Kadai and Austroasiatic languages, and that we hypothesize derives from farmers of the Yangtze River Valley. Ancient people from Taiwan also derived about 25% of their ancestry from a northern lineage that is related to, but different from, farmers of the Yellow River Basin, which suggests an additional north-to-south expansion. Fourth, ancestry from Yamnaya Steppe pastoralists arrived in western Mongolia after around 3000 BC but was displaced by previously established lineages even while it persisted in western China, as would be expected if this ancestry was associated with the spread of proto-Tocharian Indo-European languages. Two later gene flows affected western Mongolia: migrants after around 2000 BC with Yamnaya and European farmer ancestry, and episodic influences of later groups with ancestry from Turan.


Assuntos
Genoma Humano/genética , Genômica , Migração Humana/história , China , Produção Agrícola/história , Feminino , Haplótipos/genética , História Antiga , Humanos , Japão , Idioma/história , Masculino , Mongólia , Nepal , Oryza , Polimorfismo de Nucleotídeo Único/genética , Sibéria , Taiwan
6.
PLoS Biol ; 21(9): e3002282, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37676855

RESUMO

Light in the environment greatly impacts a variety of brain functions, including sleep. Clinical evidence suggests that bright light treatment has a beneficial effect on stress-related diseases. Although stress can alter sleep patterns, the effect of bright light treatment on stress-induced sleep alterations and the underlying mechanism are poorly understood. Here, we show that bright light treatment reduces the increase in nonrapid eye movement (NREM) sleep induced by chronic stress through a di-synaptic visual circuit consisting of the thalamic ventral lateral geniculate nucleus and intergeniculate leaflet (vLGN/IGL), lateral habenula (LHb), and rostromedial tegmental nucleus (RMTg). Specifically, chronic stress causes a marked increase in NREM sleep duration and a complementary decrease in wakefulness time in mice. Specific activation of RMTg-projecting LHb neurons or activation of RMTg neurons receiving direct LHb inputs mimics the effects of chronic stress on sleep patterns, while inhibition of RMTg-projecting LHb neurons or RMTg neurons receiving direct LHb inputs reduces the NREM sleep-promoting effects of chronic stress. Importantly, we demonstrate that bright light treatment reduces the NREM sleep-promoting effects of chronic stress through the vLGN/IGL-LHb-RMTg pathway. Together, our results provide a circuit mechanism underlying the effects of bright light treatment on sleep alterations induced by chronic stress.


Assuntos
Habenula , Sono de Ondas Lentas , Animais , Camundongos , Sono , Núcleo Celular , Corpos Geniculados
7.
Chem Soc Rev ; 53(1): 545, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38050457

RESUMO

Correction for 'A tutorial on asymmetric electrocatalysis' by Jonas Rein et al., Chem. Soc. Rev., 2023, https://doi.org/10.1039/D3CS00511A.

8.
J Am Chem Soc ; 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39012345

RESUMO

Alkoxy radicals are versatile reactive intermediates in organic synthesis. Here, we leverage the principle of frustrated radical pair to provide convenient access to these highly reactive species directly from tertiary alcohols via oxoammonium-mediated oxidation of the corresponding alkoxides. This approach enabled various synthetically useful transformations including ß-scission, radical cyclization, and remote C-H functionalization, giving rise to versatile alkoxyamines that can be further elaborated to various functionalities.

9.
J Am Chem Soc ; 146(7): 4380-4392, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38300825

RESUMO

The hydrofluorination of alkenes represents an attractive strategy for the synthesis of aliphatic fluorides. This approach provides a direct means to form C(sp3)-F bonds selectively from readily available alkenes. Nonetheless, conducting hydrofluorination using nucleophilic fluorine sources poses significant challenges due to the low acidity and high toxicity associated with HF and the poor nucleophilicity of fluoride. In this study, we present a new Co(salen)-catalyzed hydrofluorination of simple alkenes utilizing Et3N·3HF as the sole source of both hydrogen and fluorine. This process operates via a photoredox-mediated polar-radical-polar crossover mechanism. We also demonstrated the versatility of this method by effectively converting a diverse array of simple and activated alkenes with varying degrees of substitution into hydrofluorinated products. Furthermore, we successfully applied this methodology to 18F-hydrofluorination reactions, enabling the introduction of 18F into potential radiopharmaceuticals. Our mechanistic investigations, conducted using rotating disk electrode voltammetry and DFT calculations, unveiled the involvement of both carbocation and CoIV-alkyl species as viable intermediates during the fluorination step, and the contribution of each pathway depends on the structure of the starting alkene.

10.
Small ; 20(24): e2306859, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38155356

RESUMO

Solution-processed and efficient yellow quantum dot light-emitting diodes (QLEDs) are considered key optoelectronic devices for lighting, display, and signal indication. However, limited synthesis routes for yellow quantum dots (QDs), combined with inferior stress-relaxation of the core-shell interface, pose challenges to their commercialization. Herein, a nanostructure tailoring strategy for high-quality yellow CdZnSe/ZnSe/ZnS core/shell QDs using a "stepwise high-temperature nucleation-shell growth" method is introduced. The synthesized CdZnSe-based QDs effectively smoothed the release stress of the core-shell interface and revealed a near-unit photoluminescence quantum yield, with nonblinking behavior and matched energy level, which accelerated radiative recombination and charge injection balance for device operation. Consequently, the yellow CdZnSe-based QLEDs exhibited a peak external quantum efficiency of 23.7%, a maximum luminance of 686 050 cd m-2, and a current efficiency of 103.2 cd A-1, along with an operating half-lifetime of 428 523 h at 100 cd m-2. To the best of the knowledge, the luminance and operational stability of the device are found to be the highest values reported for yellow LEDs. Moreover, devices with electroluminescence (EL) peaks at 570-605 nm exhibited excellent EQEs, surpassing 20%. The work is expected to significantly push the development of RGBY-based display panels and white LEDs.

11.
Am Heart J ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38942221

RESUMO

BACKGROUND: It is currently uncertain whether the combination of a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor and high-intensity statin treatment can effectively reduce cardiovascular events in patients with acute coronary syndrome (ACS) who have undergone percutaneous coronary intervention (PCI) for culprit lesions. METHODS: This study protocol describes a double-blind, randomized, placebo-controlled, multicenter study aiming to investigate the efficacy and safety of combining a PCSK9 inhibitor with high-intensity statin therapy in patients with ACS following PCI. A total of 1212 patients with ACS and multiple lesions will be enrolled and randomly assigned to receive either PCSK9 inhibitor plus high-intensity statin therapy or high-intensity statin monotherapy. The randomization process will be stratified by sites, diabetes, initial presentation and use of stable (≥4 weeks) statin treatment at presentation. PCSK 9 inhibitor or its placebo is injected within 4 hours after PCI for the culprit lesion. The primary endpoint is the composite of cardiovascular death, myocardial infarction, stroke, re-hospitalization due to ACS or heart failure, or any ischemia-driven coronary revascularization at one-year follow-up between two groups. Safety endpoints mean PCSK 9 inhibitor and statin intolerance. CONCLUSION: The SHAWN study has been specifically designed to evaluate the effectiveness and safety of adding a PCSK9 inhibitor to high-intensity statin therapy in patients who have experienced ACS following PCI. The primary objective of this study is to generate new evidence regarding the potential benefits of combining a PCSK9 inhibitor with high-intensity statin treatment in reducing cardiovascular events among these patients.

12.
Microb Pathog ; 192: 106647, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38788811

RESUMO

Recent research has revealed that alterations of the gut microbiome (GM) play a comprehensive role in the pathophysiology of HF. However, findings in this field remain controversial. In this study, we focus on differences in GM diversity and abundance between HF patients and non-HF people, based on previous 16 S ribosomal RNA (16rRNA) gene sequencing. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a comprehensive search of PubMed, Web of Science, Embase, Cochrane Library, and Ovid databases using the keyword "Heart failure" and "Gastrointestinal Microbiome". A significant decrease in alpha diversity was observed in the HF patients (Chao1, I2 = 87.5 %, p < 0.001; Shannon index, I2 = 62.8 %, p = 0.021). At the phylum level, the HF group exhibited higher abundances of Proteobacteria (I2 = 92.0 %, p = 0.004) and Actinobacteria (I2 = 82.5 %, p = 0.010), while Bacteroidetes (I2 = 45.1 %, p = 0.017) and F/B ratio (I2 = 0.0 %, p<0.001) were lower. The Firmicutes showed a decreasing trend but did not reach statistical significance (I2 = 82.3 %, p = 0.127). At the genus level, the relative abundances of Streptococcus, Bacteroides, Alistipes, Bifidobacterium, Escherichia-Shigella, Enterococcus and Klebsiella were increased in the HF group, whereas Ruminococcus, Faecalibacterium, Dorea and Megamona exhibited decreased relative abundances. Dialister, Blautia and Prevotella showed decreasing trends but without statistical significance. This observational meta-analysis suggests that GM changes are associated with HF, manifesting as alterations in GM abundance, disruptions in the production of short-chain fatty acids (SCFAs) bacteria, and an increase in trimethylamine N-oxide (TMAO) producing bacteria.


Assuntos
Bactérias , Microbioma Gastrointestinal , Insuficiência Cardíaca , Humanos , Insuficiência Cardíaca/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , RNA Ribossômico 16S/genética , Proteobactérias/genética , Proteobactérias/isolamento & purificação , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação
13.
Langmuir ; 40(8): 4447-4459, 2024 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-38349871

RESUMO

High-sensitivity detection of biomarkers is of great significance to improve the accuracy of disease diagnosis and the rate of occult disease diagnosis. Using a substrate modification and two-color quantum dot (QD) nanobeads (QBs), we have developed a dual fluorescence signal-enhancement immunosensor for sensitive, simultaneous detection of interleukin 6 (IL-6) and procalcitonin (PCT) at low volumes (∼20 µL). First, the QBs compatible with QDs with different surface ligands were prepared by optimizing surfactants based on the microemulsion method. Through the use of a fluorescence-linked immunosorbent assay (FLISA), the feasibility of a dual signal-enhancement immunosensor was verified, and a 5-fold enhancement of fluorescence intensity was achieved after the directional coating of the antibodies on sulfhydryl functionalization (-SH) substrates and the preparation of QBs by using a polymer and silica double-protection method. Next, a simple polydimethylsiloxane (HS-PDMS) immunosensor with a low volume consumption was prepared. Under optimal conditions, we achieved the simultaneous detection of IL-6 and PCT with a linear range of 0.05-50 ng/mL, and the limit of detection (LOD) was 24 and 32 pg/mL, respectively. The result is comparable to two-color QBs-FLISA with a sulfhydryl microplate, even though only 20% of its volume was used. Thus, the dual fluorescence signal-enhancement HS-PDMS immunosensor offers the capability of early microvolume diagnosis of diseases, while the detection of inflammatory factors is clinically important for assisting disease diagnosis and determining disease progression.


Assuntos
Técnicas Biossensoriais , Pontos Quânticos , Pró-Calcitonina , Interleucina-6 , Imunoensaio/métodos , Técnicas Biossensoriais/métodos , Limite de Detecção
14.
J Org Chem ; 89(3): 1927-1940, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38231008

RESUMO

Anodic cyclization reactions can provide a versatile method for converting newly obtained chiral lactols to densely functionalized cyclic building blocks. The method works by first converting the lactol into an electron-rich olefin and then oxidatively generating a radical cation that is trapped by a nucleophile. Historically, such reactions have benefited from the use of less polar radical cations when the trapping nucleophile is a heteroatom and more polar radical cations when the reaction forms C-C bonds. This forced one to optimize underperforming reactions by resynthesizing the substrate. Here, we show that by taking advantage of methods that serve to drive a reversible initial cyclization reaction toward the product, this dichotomy and need to manipulate the substrate can be avoided. Two such methods were utilized: a faster second oxidation step and a mediated electrolysis. Both led to successful cyclizations using a polar radical cation and heteroatom nucleophiles.

15.
Inorg Chem ; 63(10): 4604-4613, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38395777

RESUMO

Nontoxic, highly sensitive InP quantum dot (QD) fluorescent immunoassay probes are promising biomedical detection modalities due to their unique properties. However, InP-based QDs are prone to surface oxidation, and the stability of InP QD-based probes in biocompatible environments remains a crucial challenge. Although the thick shell can provide some protection during the phase transfer process of hydrophobic QDs, the photoluminescence quantum yield (PLQY) is generally decreased because of the contradiction between lattice stress relaxation and thick shell growth. Herein, we developed thick-shell InP-based core/shell QDs by inserting a ZnSeS alloy layer. The ternary ZnSeS intermediate shell could effectively facilitate lattice stress relaxation and passivate the defect states. The synthesized InP/ZnSe/ZnSeS/ZnS core/alloy shell/shell QDs (CAS-InP QDs) with nanostructure tailoring revealed a larger size, high PLQY (90%), and high optical stability. After amphiphilic polymer encapsulation, the aqueous CAS-InP QDs presented almost constant fluorescence attenuation and stable PL intensity under different temperatures, UV radiation, and pH solutions. The CAS-InP QDs were excellent labels of the fluorescence-linked immunosorbent assay (FLISA) for detecting C-reactive protein (CRP). The biotin-streptavidin (Bio-SA) system was first introduced in the FLISA to further improve the sensitivity, and the CAS-InP QDs-based SA-Bio sandwich FLISA realized the detection of CRP with an impressive limit of detection (LOD) of 0.83 ng/mL. It is believed that the stable and sensitive InP QD fluorescent probes will drive the rapid development of future eco-friendly, cost-effective, and sensitive in vitro diagnostic kits.


Assuntos
Nanoestruturas , Pontos Quânticos , Biotina , Estreptavidina , Corantes Fluorescentes , Ligas
16.
Bioorg Chem ; 145: 107210, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38364551

RESUMO

Hecogenin (HCG), a steroidal sapogenin, possesses good antitumor properties. However, the application of HCG for cancer treatment has been hindered primarily by its moderate potency. In this study, we incorporated triphenylphosphonium cation (TPP+) at the C-3 and C-12 positions through different lengths of alkyl chains to target mitochondria and enhance the efficacy and selectivity of the parent compound. Cytotoxicity screening revealed that most of the target compounds exhibited potent antiproliferative activity against five human cancer cell lines (MKN45, A549, HCT-116, MCF-7, and HepG2). Structure-activity relationship studies indicated that the TPP+ group significantly enhanced the antiproliferative potency of HCG. Among these compounds, 3c demonstrated remarkable potency against MKN45 cells with an IC50 value of 0.48 µM, significantly more effective than its parent compound HCG (IC50 > 100 µM). Further investigations into the mechanism of action revealed that 3c induced apoptosis of MKN45 cells through the mitochondrial pathway. In a zebrafish xenograft model, 3c inhibited the proliferation of MKN45 cells. Overall, these results suggest that 3c, with potent antiproliferative activity, may serve as a valuable scaffold for developing new antitumor agents.


Assuntos
Antineoplásicos , Compostos Organofosforados , Sapogeninas , Animais , Humanos , Estrutura Molecular , Sapogeninas/farmacologia , Peixe-Zebra , Ensaios de Seleção de Medicamentos Antitumorais , Relação Estrutura-Atividade , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células , Apoptose , Desenho de Fármacos
17.
BMC Womens Health ; 24(1): 222, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38581038

RESUMO

BACKGROUND: The evidence regarding the association of reproductive factors with cardiovascular diseases (CVDs) is limited. AIMS: To investigate the relationship of reproductive factors with the risk of CVDs, as well as all-cause and cardiovascular mortality. METHODS: This study included 16,404 adults with reproductive factors from the National Health and Nutrition Examination Survey (NHANES) and followed up until 31 December 2019. Logistic models and restricted cubic spline models were used to assess the association of reproductive factors with CVDs. COX proportional hazards models and restricted cubic spline models, with adjustment for potential confounding, were employed to analyze the relation between reproductive factors and cardiovascular and all-cause death. RESULTS: There is a nonlinear relationship between age at menarche and CVDs. Age at menopause ≤ 11(OR 1.36, 95% CI 1.10-1.69) was associated with an increased risk of CVDs compared to ages 12-13 years. Age at Menopause ≤ 44 (OR 1.69, 95% CI 1.40-2.03) was associated with increased CVDs compared to age 35-49 years. Number of pregnancies ≥ 5(OR 1.26, 95% CI 1.02-1.55) was associated with an increased risk of CVDs compared to one pregnancy. In continuous variable COX regression models, a later age at menopause (HR 0.98, 95% CI 0.97-0.99) and a longer reproductive lifespan (HR 0.98, 95% CI 0.97-0.99) were associated with a decreased risk of all-cause death. A later age at menopause (HR 0.98, 95% CI 0.97-0.99) and a longer reproductive lifespan (HR 0.98, 95% CI 0.97-0.99) were associated with a decreased risk of cardiac death. CONCLUSIONS: Female reproductive factors are significant risk factors for CVDs American women.


Assuntos
Doenças Cardiovasculares , Gravidez , Adulto , Feminino , Estados Unidos/epidemiologia , Humanos , Criança , Adolescente , Pessoa de Meia-Idade , Inquéritos Nutricionais , Menopausa , Reprodução , Fatores de Risco
18.
Chem Soc Rev ; 52(23): 8106-8125, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-37910160

RESUMO

Electrochemistry has emerged as a powerful means to enable redox transformations in modern chemical synthesis. This tutorial review delves into the unique advantages of electrochemistry in the context of asymmetric catalysis. While electrochemistry has historically been used as a green and mild alternative for established enantioselective transformations, in recent years asymmetric electrocatalysis has been increasingly employed in the discovery of novel asymmetric methodologies based on reaction mechanisms unique to electrochemistry. This tutorial review first provides a brief tutorial introduction to electrosynthesis, then explores case studies on homogenous small molecule asymmetric electrocatalysis. Each case study serves to highlight a key advance in the field, starting with the historic electrification of known asymmetric transformations and culminating with modern methods relying on unique electrochemical mechanistic sequences. Finally, we highlight case studies in the emerging reasearch areas at the interface of asymmetric electrocatalysis with biocatalysis and heterogeneous catalysis.

19.
BMC Oral Health ; 24(1): 238, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38355448

RESUMO

BACKGROUND: Facial nerve injury often results in poor prognosis due to the challenging process of nerve regeneration. Neuregulin-1, a human calmodulin, is under investigation in this study for its impact on the reparative capabilities of Dental Pulp Stem Cells (DPSCs) in facial nerve injury. METHODS: Lentivirus was used to transfect and construct Neuregulin-1 overexpressed DPSCs. Various techniques assessed the effects of Neuregulin-1: osteogenic induction, lipid induction, Reverse Transcription Polymerase Chain Reaction, Western Blot, Cell Counting Kit-8 assay, wound healing, immunofluorescence, Phalloidin staining, nerve stem action potential, Hematoxylin-eosin staining, transmission electron microscopy, and immunohistochemistry. RESULTS: Neuregulin-1 effectively enhanced the proliferation, migration, and cytoskeletal rearrangement of DPSCs, while simultaneously suppressing the expression of Ras homolog gene family member A (RhoA) and Microfilament actin (F-actin). These changes facilitated the neural differentiation of DPSCs. Additionally, in vivo experiments showed that Neuregulin-1 expedited the restoration of action potential in the facial nerve trunk, increased the thickness of the myelin sheath, and stimulated axon regeneration. CONCLUSION: Neuregulin-1 has the capability to facilitate the repair of facial nerve injuries by promoting the regenerative capacity of DPSCs. Thus, Neuregulin-1 is a significant potential gene in the reparative processes of nerve damage.


Assuntos
Polpa Dentária , Traumatismos do Nervo Facial , Humanos , Axônios , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Traumatismos do Nervo Facial/metabolismo , Regeneração Nervosa/fisiologia , Neuregulina-1/metabolismo , Células-Tronco/metabolismo
20.
J Am Chem Soc ; 145(31): 16966-16972, 2023 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-37499221

RESUMO

We present a new, unified approach for the transformation of benzylic and allylic alcohols, aldehydes, and ketones into boronic esters under electroreductive conditions. Key to our strategy is the use of readily available pinacolborane, which serves both as an activator and an electrophile by first generating a redox-active trialkylborate species and then delivering the desired deoxygenatively borylated product. This strategy is applicable to a variety of substrates and can be employed for the late-stage functionalization of complex molecules.

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