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1.
Zhongguo Zhong Yao Za Zhi ; 49(3): 763-769, 2024 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-38621880

RESUMO

This study aims to investigate the effect of Erchen Decoction(ECD) on liver mitochondrial function in mice with a high-fat diet and its possible mechanism. A total of sixty C57BL/6J mice were randomly divided into a normal group, high-fat group, ECD group, mTORC1 activator(MHY) group, ECD+MHY group, and polyene phosphatidyl choline(PPC) group, with 10 rats in each group. The normal group was given a normal diet, and the other groups were fed a high-fat diet for 20 weeks. At the 17th week, the ECD group and ECD+MHY group were given ECD(8.7 g·kg~(-1)) daily, and the PPC group was given PPC(0.18 g·kg~(-1)) daily, while the remaining groups were given normal saline(0.01 mL·g~(-1)) daily for four weeks. In the 19th week, the MHY group and ECD+MHY group were injected intraperitoneally with MHY(5 mg·kg~(-1)) every other day for two weeks. During the experiment, the general conditions of the mice were observed. The contents of triglyceride(TG) and total cholesterol(TC) in serum were measured. Morphological changes in liver tissue were examined through HE and oil red O staining. The content of adenosine triphosphate(ATP) was determined using chemiluminescence, and mitochondrial membrane potential was assessed using a fluorescence probe(JC-1). Western blot was performed to detect the expression of rapamycin target protein complex 1(mTOR1), ribosomal protein S6 kinase B1(S6K), sterol regulatory element binding protein 1(SREBP1), and caveolin 1(CAV1). RESULTS:: revealed that compared with the normal group, the mice in the high-fat group exhibited significant increases in body weight and abdominal circumference(P<0.01). Additionally, there were significant increases in TG and TC levels(P<0.01). HE and oil red O staining showed that the boundaries of hepatic lobules were unclear; hepatocytes were enlarged, round, and irregularly arranged, with obvious lipid droplet deposition and inflammatory cell infiltration. The liver ATP content and mitochondrial membrane potential decreased significantly(P<0.01). The expression of p-mTOR, p-S6K, and n-SREBP1 increased significantly(P<0.01), while the expression of CAV1 decreased significantly(P<0.01). Compared with the high-fat group, the body weight and TG content of mice in the ECD group and PPC group decreased significantly(P<0.05). Improvements were observed in hepatocyte morphology, lipid deposition, and inflammatory cell infiltration. Furthermore, there were significant increases in ATP content and mitochondrial membrane potential(P<0.05 or P<0.01). The expression of p-mTOR, p-S6K, and n-SREBP1 decreased significantly in the ECD group(P<0.01), while CAV1 expression increased significantly(P<0.01). However, the indices mentioned above did not show improvement in the MHY group. When the ECD+MHY group was compared with the MHY group, there were significant reductions in body weight and TG contents(P<0.05). The morphological changes of hepatocytes, lipid deposition, and inflammatory cell infiltration were recovered. Moreover, there were significant increases in liver ATP content and mitochondrial membrane potential(P<0.05 or P<0.05). The expression of p-mTOR, p-S6K, and n-SREBP1 decreased significantly(P<0.01), while CAV1 expression increased significantly(P<0.01). In conclusion, ECD can improve mitochondrial function by regulating the mTORC1/SREBP1/CAV1 pathway. This mechanism may be involved in the resolution of phlegm syndrome and the regulation of lipid metabolism.


Assuntos
Compostos Azo , Dieta Hiperlipídica , Hepatopatia Gordurosa não Alcoólica , Camundongos , Ratos , Animais , Dieta Hiperlipídica/efeitos adversos , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/farmacologia , Caveolina 1/metabolismo , Caveolina 1/farmacologia , Camundongos Endogâmicos C57BL , Fígado , Hepatopatia Gordurosa não Alcoólica/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Triglicerídeos/metabolismo , Peso Corporal , Trifosfato de Adenosina/farmacologia
2.
Cell Death Dis ; 15(4): 289, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38653973

RESUMO

GATA-binding protein 4 (GATA4) is recognized for its significant roles in embryogenesis and various cancers. Through bioinformatics and clinical data, it appears that GATA4 plays a role in breast cancer development. Yet, the specific roles and mechanisms of GATA4 in breast cancer progression remain elusive. In this study, we identify GATA4 as a tumor suppressor in the invasion and migration of breast cancer. Functionally, GATA4 significantly reduces the transcription of MMP9. On a mechanistic level, GATA4 diminishes MMP9 transcription by interacting with p65 at the NF-κB binding site on the MMP9 promoter. Additionally, GATA4 promotes the recruitment of HDAC1, amplifying the bond between p65 and HDAC1. This leads to decreased acetylation of p65, thus inhibiting p65's transcriptional activity on the MMP9 promoter. Moreover, GATA4 hampers the metastasis of breast cancer in vivo mouse model. In summary, our research unveils a novel mechanism wherein GATA4 curtails breast cancer cell metastasis by downregulating MMP9 expression, suggesting a potential therapeutic avenue for breast cancer metastasis.


Assuntos
Neoplasias da Mama , Movimento Celular , Fator de Transcrição GATA4 , Regulação Neoplásica da Expressão Gênica , Histona Desacetilase 1 , Metaloproteinase 9 da Matriz , Invasividade Neoplásica , Humanos , Fator de Transcrição GATA4/metabolismo , Fator de Transcrição GATA4/genética , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Neoplasias da Mama/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/genética , Feminino , Movimento Celular/genética , Histona Desacetilase 1/metabolismo , Histona Desacetilase 1/genética , Animais , Acetilação , Linhagem Celular Tumoral , Camundongos , Fator de Transcrição RelA/metabolismo , Transcrição Gênica , Regiões Promotoras Genéticas/genética , Camundongos Nus , Camundongos Endogâmicos BALB C
3.
J Nutr Biochem ; : 109649, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38642842

RESUMO

Obesity and its related metabolic diseases bring great challenges to public health. In-depth understanding on the efficacy of weight-loss interventions is critical for long-term weight control. Our study demonstrated the comparable efficacy of exercise (EX), intermittent fasting (IF), or the change of daily diet from an unhealthy to a normal chow (DR) for weight reduction, but largely divergently affected metabolic status and transcriptome of subcutaneous fat, scapular brown fat, skeletal muscles and liver in high-fat-high-fructose diet (HFHF) induced obese mice. EX and IF reduced systematic inflammation, improved glucose and lipid metabolism in liver and muscle, and amino acid metabolism and thermogenesis in adipose tissues. EX exhibited broad regulatory effects on TCA cycle, carbon metabolism, thermogenesis, propanoate-, fatty acid and amino acid metabolism across multiple tissues. IF prominently affected genes involved in mitophagy and autophagy in adipose tissues and core genes involved in butanoate metabolism in liver. DR however failed to improve metabolic homeostasis and biological dysfunctions in obese mice. Notably, by exploring potential inter-organ communication, we identified an obesity-resistant-like gene profile that were strongly correlated with HFHF induced metabolic derangements and could predict the degree of weight regain induced by the follow-up HFHF diet. Among them, 12 genes (e.g., Gdf15, Tfrc, Cdv3, Map2k4 and Nqo1) were causally associated with human metabolic traits, i.e., BMI, body fat mass, HbA1C, fasting glucose and cholesterol. Our findings provide critical groundwork for improved understanding the impacts of weight-loss interventions on host metabolism. The identified genes predicting weight regain may be considered regulatory targets for improving the long-term weight control.

4.
Carbohydr Polym ; 332: 121945, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38431423

RESUMO

Tissue-engineered is an effective method for repairing critical-size bone defects. The application of bioactive scaffold provides artificial matrix and suitable microenvironment for cell recruitment and extracellular matrix deposition, which can effectively accelerate the process of tissue regeneration. Among various scaffold properties, appropriate pore structure and distribution have been proven to play a crucial role in inducing cell infiltration differentiation and in-situ tissue regeneration. In this study, a chitosan (CS) /silk fibroin (SF) /bioactive glass (BG) composite scaffold with distinctive radially oriented pore structure was constructed. The composite scaffolds had stable physical and chemical properties, a unique pore structure of radial arrangement from the center to the periphery and excellent mechanical properties. In vitro biological studies indicated that the CS/SF/BG scaffold could promote osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and the expression of related genes due to the wide range of connected pore structures and released active elements. Furthermore, in vivo study showed CS/SF/BG scaffold with radial pores was more conducive to the repair of skull defects in rats with accelerated healing speed during the bone tissue remodeling process. These results demonstrated the developed CS/SF/BG scaffold would be a promising therapeutic strategy for the repair of bone defects regeneration.


Assuntos
Quitosana , Fibroínas , Ratos , Animais , Fibroínas/química , Tecidos Suporte/química , Osteogênese , Quitosana/química , Engenharia Tecidual/métodos , Regeneração Óssea
5.
Cancer Med ; 13(4): e7065, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38457206

RESUMO

INTRODUCTION: Near-infrared autofluorescence imaging (NIFI) can be used to identify parathyroid gland (PG) during surgery. The purpose of the study is to establish a new model, help surgeons better identify, and protect PGs. METHODS: Five hundred and twenty three NIFI images were selected. The PGs were recorded by NIFI and marked with artificial intelligence (AI) model. The recognition rate for PGs was calculated. Analyze the differences between surgeons of different years of experience and AI recognition, and evaluate the diagnostic and therapeutic efficacy of AI model. RESULTS: Our model achieved 83.5% precision and 57.8% recall in the internal validation set. The visual recognition rate of AI model was 85.2% and 82.4% on internal and external sets. The PG recognition rate of AI model is higher than that of junior surgeons (p < 0.05). CONCLUSIONS: This AI model will help surgeons identify PGs, and develop their learning ability and self-confidence.


Assuntos
Aprendizado Profundo , Glândulas Paratireoides , Humanos , Glândulas Paratireoides/diagnóstico por imagem , Glândulas Paratireoides/cirurgia , Paratireoidectomia/métodos , Tireoidectomia/métodos , Inteligência Artificial , Imagem Óptica/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos
6.
Int J Mol Sci ; 25(6)2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38542476

RESUMO

Sugar transporters play important roles in plant growth and development, flowering and fruiting, as well as responses to adverse abiotic and biotic environmental conditions. Lilies (Lilium spp.) are some of the most representative ornamental bulbous flowers. Sugar metabolism is critical for bulb formation in lilies; therefore, clarifying the amount and expression pattern of sugar transporters is essential for further analyzing their roles in bulb formation. In this study, based on the transcriptome data of the Lilium Oriental hybrid 'Sorbonne' and Lilium × formolongi, a total of 69 and 41 sugar transporters were identified in 'Sorbonne' and Lilium × formolongi, respectively, by performing bioinformatics analysis. Through phylogenetic analysis, monosaccharide transporters (MSTs) can be divided into seven subfamilies, sucrose transporters (SUTs) can be divided into three subgroups, and sugars will eventually be exported transporters (SWEETs) can be divided into four clades. According to an analysis of conserved motifs, 20, 14, and 12 conserved motifs were predicted in MSTs, SUTs, and SWEETs, respectively. A conserved domain analysis showed that MSTs and SUTs contained a single domain, whereas most of the SWEETs harbored two MtN3/saliva domains, also known as a PQ-loop repeat. The LohINT1, which was predicted to have a smaller number of transmembrane structural domains, was cloned and analyzed for subcellular localization. It was found that the LohINT1 protein is mainly localized in the cell membrane. In addition, the expression analysis indicated that 22 LohMSTs, 1 LohSUTs, and 5 LohSWEETs were upregulated in 'Sorbonne' 1 day after scale detachment treatment, suggesting that they may regulate the initiation of the bulblet. A total of 10 LflMSTs, 1 LflSUTs, and 6 LflSWEETs were upregulated 4~6 months after sowing, which corresponds to the juvenile-to-adult transition phase of Lilium × formolongi, suggesting that they may also play a role in the accompanying bulb swelling process. Combined with quantitative real-time PCR (qRT-PCR) analysis, LohSTP8 and LohSTP12 were significantly overexpressed during the extremely early stage of bulblet initiation, and LflERD6.3 was significantly overexpressed during the growth of the underground bulblet, suggesting that they may be key sugar transporters in the formation of lily bulbs, which needs further functional verification.


Assuntos
Lilium , Lilium/metabolismo , Filogenia , Metabolismo dos Carboidratos , Transcriptoma , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Açúcares/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
7.
Chem Commun (Camb) ; 60(27): 3705-3708, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38477139

RESUMO

C-N bonds play a critical role in pharmaceutical, agrochemical, and materials sciences, necessitating ever-better methods to forge this linkage. Here we report a simple procedure for direct C(sp3)-H azidation using iron or manganese catalysis and a nucleophilic azide source. All reagents are commercially available, the experimental procedure is simple, and we can use the C-H donor substrate as the limiting reagent, a challenge for many C-H azidation methods. Preliminary experiments are consistent with a hydrogen atom transfer (HAT)/radical ligand transfer (RLT) radical cascade mechanism and a wide variety of substrates can be azidated in moderate to high yields.

8.
Phytochemistry ; 222: 114071, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38552709

RESUMO

Eight pairs of dihydrohomoisoflavonoids (1-8), including four pairs of enantiomeric aglycones [(R,S)-portulacanones B (1) and C (2) and (R,S)-oleracones C (3) and Q (4)] and four pairs of epimeric glycosides [portulacasides A-D and epiportulacasides A-D (5-8)], were obtained from Portulaca oleracea L. Among them, (R,S)-oleracone Q (4) and four pairs of epimeric glycosides (5-8) were reported for the first time. The 50% EtOH fraction from the 70% EtOH extract prevented HepG2 human liver cancer cell damage induced by N-acetyl-p-aminophenol (APAP), and the cell survival rate was 62.3%. Portulacaside B (6a), which was isolated from the 50% EtOH fraction, exhibited hepatoprotective and anti-inflammatory effects. The compound increased the survival rate of APAP-damaged HepG2 human liver cancer cells from 40.0% to 51.2% and reduced nitric oxide production in RAW 264.7 macrophages, resulting in an inhibitory rate of 46.8%.

9.
Nat Commun ; 15(1): 1944, 2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38431703

RESUMO

Forecasting large earthquakes along active faults is of critical importance for seismic hazard assessment. Statistical models of recurrence intervals based on compilations of paleoseismic data provide a forecasting tool. Here we compare five models and use Bayesian model-averaging to produce time-dependent, probabilistic forecasts of large earthquakes along 93 fault segments worldwide. This approach allows better use of the measurement errors associated with paleoseismic records and accounts for the uncertainty around model choice. Our results indicate that although the majority of fault segments (65/93) in the catalogue favour a single best model, 28 benefit from a model-averaging approach. We provide earthquake rupture probabilities for the next 50 years and forecast the occurrence times of the next rupture for all the fault segments. Our findings suggest that there is no universal model for large earthquake recurrence, and an ensemble forecasting approach is desirable when dealing with paleoseismic records with few data points and large measurement errors.

10.
Front Chem ; 12: 1339364, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38318112

RESUMO

Aconitine (AC), which is the primary bioactive diterpene alkaloid derived from Aconitum L plants, have attracted considerable interest due to its unique structural feature. Additionally, AC demonstrates a range of biological activities, such as its ability to enhance cardiac function, inhibit tumor growth, reduce inflammation, and provide analgesic effects. However, the structure-activity relationships of AC are remain unclear. A clear understanding of these relationships is indeed critical in developing effective biomedical applications with AC. In line with these challenges, this paper summarized the structural characteristics of AC and relevant functional and bioactive properties and the structure-activity relationships presented in biomedical applications. The primary temporal scope of this review was established as the period spanning from 2010 to 2023. Subsequently, the objective of this review was to provide a comprehensive understanding of the specific action mechanism of AC, while also exploring potential novel applications of AC derivatives in the biomedical field, drawing upon their structural characteristics. In conclusion, this review has provided a comprehensive analysis of the challenges and prospects associated with AC in the elucidation of structure-bioactivity relationships. Furthermore, the importance of exploring modern biotechnology approaches to enhance the potential biomedical applications of AC has been emphasized.

11.
J Hazard Mater ; 465: 133456, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38211525

RESUMO

Aerobic composting increases the content of soluble nutrients and facilitates the safe treatment of livestock manure. Although different taxa play crucial roles in maintaining ecological functionality, the succession patterns of community composition and assembly of rare and abundant subcommunities during aerobic composting under antibiotic stress and their contributions to ecosystem functionality remain unclear. Therefore, this study used 16 S rRNA gene sequencing technology to reveal the response mechanisms of diverse microbial communities and the assembly processes of abundant and rare taxa to amoxicillin during aerobic composting. The results indicated that rare taxa exhibited distinct advantages in terms of diversity, community composition, and ecological niche width compared with abundant taxa, highlighting their significance in maintaining ecological community dynamics. In addition, deterministic (heterogeneous selection) and stochastic processes (dispersal limitation) play roles in the community succession and functional dynamics of abundant and rare subcommunities. The findings of this study may contribute to a better understanding of the relative importance of deterministic and stochastic assembly processes in composting systems, and the ecological functions of diverse microbial communities, ultimately leading to improved ecological environment.


Assuntos
Compostagem , Microbiota , Amoxicilina , RNA Ribossômico
12.
Adv Sci (Weinh) ; 11(11): e2307982, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38168537

RESUMO

Evaluating and understanding the effect of manufacturing processes on the creep performance in superalloys poses a significant challenge due to the intricate composition involved. This study presents a machine-learning strategy capable of evaluating the effect of the heat treatment process on the creep performance of superalloys and predicting creep rupture life with high accuracy. This approach integrates classification and regression models with domain-specific knowledge. The physical constraints lead to significantly enhanced prediction accuracy of the classification and regression models. Moreover, the heat treatment process is evaluated as the most important descriptor by integrating machine learning with superalloy creep theory. The heat treatment design of Waspaloy alloy is used as the experimental validation. The improved heat treatment leads to a significant enhancement in creep performance (5.5 times higher than the previous study). The research provides novel insights for enhancing the precision of predicting creep rupture life in superalloys, with the potential to broaden its applicability to the study of the effects of heat treatment processes on other properties. Furthermore, it offers auxiliary support for the utilization of machine learning in the design of heat treatment processes of superalloys.

13.
RSC Adv ; 14(3): 1952-1961, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38192314

RESUMO

Schiff bases have remarkable anticancer activity and are used for glioma therapy. However, the poor water solubility/dispersibility limits their therapeutic potential in biological systems. To address this issue, carbon dots (CDs) have been utilized to enhance the dispersibility in water and biological efficacy of Schiff bases. The amino groups on the surface of CDs were conjugated effectively with the aldehyde group of terephthalaldehyde to form novel CD-based Schiff bases (CDSBs). The results of the MTT assays demonstrate that CDSBs have significant anticancer activity in glioma GL261 cells and U251 cells, with IC50 values of 17.9 µg mL-1 and 14.9 µg mL-1, respectively. CDSBs have also been found to have good biocompatibility with normal glial cells. The production of reactive oxygen species (ROS) in GL261 glioma cells showed that CDSBs, at a concentration of 44 µg mL-1, resulted in approximately 13 times higher intracellular ROS production than in the control group. These experiments offer evidence that CDSBs induce mitochondrial damage, leading to a reduction in mitochondrial membrane potential in GL261 cells. In particular, in this work, CDs serve not as carriers, but as an integral part of the anticancer drugs, which can expand the role of CDs in cancer treatment.

14.
Glob Chang Biol ; 30(1): e17147, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38273514

RESUMO

Organo-mineral interactions have been regarded as the primary mechanism for the stabilization of soil organic carbon (SOC) over decadal to millennial timescales, and the capacity for soil carbon (C) storage has commonly been assessed based on soil mineralogical attributes, particularly mineral surface availability. However, it remains contentious whether soil C sequestration is exclusively governed by mineral vacancies, making it challenging to accurately predict SOC dynamics. Here, through a 400-day incubation experiment using 13 C-labeled organic materials in two contrasting soils (i.e., Mollisol and Ultisol), we show that despite the unsaturation of mineral surfaces in both soils, the newly incorporated C predominantly adheres to "dirty" mineral surfaces coated with native organic matter (OM), demonstrating the crucial role of organo-organic interactions in exogenous C sequestration. Such interactions lead to multilayered C accumulation that is not constrained by mineral vacancies, a process distinct from direct organo-mineral contacts. The coverage of native OM by new C, representing the degree of organo-organic interactions, is noticeably larger in Ultisol (~14.2%) than in Mollisol (~5.8%), amounting to the net retention of exogenous C in Ultisol by 0.2-1.3 g kg-1 and in Mollisol by 0.1-1.0 g kg-1 . Additionally, organo-organic interactions are primarily mediated by polysaccharide-rich microbial necromass. Further evidence indicates that iron oxides can selectively preserve polysaccharide compounds, thereby promoting the organo-organic interactions. Overall, our findings provide direct empirical evidence for an overlooked but critically important pathway of C accumulation, challenging the prevailing "C saturation" concept that emphasizes the overriding role of mineral vacancies. It is estimated that, through organo-organic interactions, global Mollisols and Ultisols might sequester ~0.1-1.0 and ~0.3-1.7 Pg C per year, respectively, corresponding to the neutralization of ca. 0.5%-3.0% of soil C emissions or 5%-30% of fossil fuel combustion globally.


Assuntos
Carbono , Solo , Minerais , Polissacarídeos
15.
Tissue Eng Regen Med ; 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38294593

RESUMO

BACKGROUND: Craniomaxillofacial tissue defects are clinical defects involving craniomaxillofacial and oral soft and hard tissues. They are characterized by defect-shaped irregularities, bacterial and inflammatory environments, and the need for functional recovery. Conventional clinical treatments are currently unable to achieve regeneration of high-quality oral craniomaxillofacial tissue. As a natural biomaterial, silk fibroin (SF) has been widely studied in biomedicine and has broad prospects for use in tissue regeneration. Hydrogels made of SF showed excellent water retention, biocompatibility, safety and the ability to combine with other materials. METHODS: To gain an in-depth understanding of the current development of SF, this article reviews the structure, preparation and application prospects in oral and craniomaxillofacial tissue regenerative medicine. It first briefly introduces the structure of SF and then summarizes the principles, advantages and disadvantages of the different cross-linking methods (physical cross-linking, chemical cross-linking and double network structure) of SF. Finally, the existing research on the use of SF in tissue engineering and the prospects of using SF with different cross-linking methods in oral and craniomaxillofacial tissue regeneration are also discussed. CONCLUSIONS: This review is intended to show the advantages of SF hydrogels in tissue engineering and provides theoretical support for establishing novel and viable silk protein hydrogels for regeneration.

17.
Curr Sports Med Rep ; 22(12): 414-422, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38055751

RESUMO

ABSTRACT: Today's youth are weaker than previous generations, and measurable reductions in physical fitness are beginning to emerge. Without targeted initiatives that recognize the foundational importance of resistance training, weaker children and adolescents may be more likely to experience the inevitable consequences of neuromuscular dysfunction and less likely to experience the pleiotropic benefits of exercise and sport. Early exposure to strength-building activities is needed to prepare today's youth for ongoing participation in varied physical activities throughout this developmental phase of life. The novel iceberg of physical development is a metaphoric image that illustrates the sequential and cumulative influence of muscular strength on motor skills and physical abilities. Efforts to enhance the physical capacity of youth should include resistive skills that improve basic movement patterns and enhance motoric competence. A shift in our conceptual thinking about youth resistance training is needed to alter the current trajectory toward physical inactivity and related comorbidities.


Assuntos
Aptidão Física , Esportes , Criança , Humanos , Adolescente , Força Muscular , Exercício Físico , Destreza Motora
18.
Chem Sci ; 15(1): 124-133, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38131080

RESUMO

Ligand-to-metal charge transfer (LMCT) is a mechanistic strategy that provides a powerful tool to access diverse open-shell species using earth abundant elements and has seen tremendous growth in recent years. However, among many reaction manifolds driven by LMCT reactivity, a general and catalytic protocol for modular difunctionalization of alkenes remains unknown. Leveraging the synergistic cooperation of iron-catalyzed ligand-to-metal charge transfer and radical ligand transfer (RLT), here we report a photocatalytic, modular difunctionalization of alkenes using inexpensive iron salts catalytically to function as both radical initiator and terminator. Additionally, strategic use of a fluorine atom transfer reagent allows for general fluorochlorination of alkenes, providing the first example of interhalogen compound formation using earth abundant element photocatalysis. Broad scope, mild conditions and versatility in converting orthogonal nucleophiles (TMSN3 and NaCl) directly into corresponding open-shell radical species are demonstrated in this study, providing a robust means towards accessing vicinal diazides and homo-/hetero-dihalides motifs catalytically. These functionalities are important precursors/intermediates in medicinal and material chemistry. Preliminary mechanistic studies support the radical nature of these transformations, disclosing the tandem LMCT/RLT as a powerful reaction manifold in catalytic olefin difunctionalization.

19.
Nat Chem ; 15(12): 1683-1692, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37957278

RESUMO

Incorporation of fluoroalkyl motifs in pharmaceuticals can enhance the therapeutic profiles of the parent molecules. The hydrofluoroalkylation of alkenes has emerged as a promising route to diverse fluoroalkylated compounds; however, current methods require superstoichiometric oxidants, expensive/oxidative fluoroalkylating reagents and precious metals, and often exhibit limited scope, making a universal protocol that addresses these limitations highly desirable. Here we report the hydrofluoroalkylation of alkenes with cheap, abundant and available fluoroalkyl carboxylic acids as the sole reagents. Hydrotrifluoro-, difluoro-, monofluoro- and perfluoroalkylation are all demonstrated, with broad scope, mild conditions (redox neutral) and potential for late-stage modification of bioactive molecules. Critical to success is overcoming the exceedingly high redox potential of feedstock fluoroalkyl carboxylic acids such as trifluoroacetic acid by leveraging cooperative earth-abundant, inexpensive iron and redox-active thiol catalysis, enabling these reagents to be directly used as hydroperfluoroalkylation donors without pre-activation. Preliminary mechanistic studies support the radical nature of this cooperative process.

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