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1.
Angew Chem Int Ed Engl ; 63(4): e202317348, 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38032339

RESUMEN

Herein, we describe our synthetic efforts toward the pupukeanane natural products, in which we have completed the first enantiospecific route to 2-isocyanoallopupukeanane in 10 steps (formal synthesis), enabled by a key Pd-mediated cyclization cascade. This subsequently facilitated an unprecedented bio-inspired "contra-biosynthetic" rearrangement, providing divergent access to 9-isocyanopupukeanane in 15 steps (formal synthesis). Computational studies provide insight into the nature of this rearrangement.

2.
Chemistry ; 29(52): e202301550, 2023 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-37219499

RESUMEN

We report a detailed experimental and theoretical analysis of through-space arene activation with halogens, tetrazoles and achiral esters and amides. Contrary to previously assumed direct activation through σ-complex stabilization, our results suggest that these reactions proceed by a relay mechanism wherein the lone pair-containing activators form exothermic π-complexes with electrophilic nitronium ion before transferring it to the probe ring through low barrier transition states. Noncovalent interactions (NCI) plots and Quantum Theory of Atoms in Molecules (QTAIM) analyses depict favorable interactions between the Lewis base (LB) and the nitronium ion in the precomplexes and the transition states, suggesting directing group participation throughout the mechanism. The regioselectivity of substitution also comports with a relay mechanism. In all, these data pave the way for an alternate platform of electrophilic aromatic substitution (EAS) reactions.

3.
Anal Chem ; 94(2): 1302-1307, 2022 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-34957818

RESUMEN

Accurate size analysis of nanoparticles (NPs) is vital for nanotechnology. However, this cannot be realized based on conventional single-nanoparticle collision (SNC) because the current intensity, a thermodynamic parameter of SNC for sizing NPs, is always smaller than the theoretical value due to the effect of NP movements on the electrode surface. Herein, a size-dependent dynamic parameter of SNC, current lifetime, which refers to the time that the current intensity decays to 1/e of the original value, was originally utilized to distinguish differently sized NPs. Results showed that the current lifetime increased with NP size. After taking the current lifetime into account rather than the current intensity, the overlap rates for the peak-type current transients of differently sized Pt NPs (10 and 15 nm) and Au NPs (18 and 35 nm) reduced from 73 and 7% to 45 and 0%, respectively, which were closer to the theoretical values (29 and 0%). Hence, the proposed SNC dynamics-based method holds great potential for developing reliable electrochemical approaches to evaluate NP sizes accurately.


Asunto(s)
Nanopartículas del Metal , Nanopartículas , Electrodos , Nanotecnología
4.
J Am Chem Soc ; 143(2): 1088-1097, 2021 01 20.
Artículo en Inglés | MEDLINE | ID: mdl-33400509

RESUMEN

Carbocation rearrangement reactions are of great significance to synthetic and biosynthetic chemistry. In pursuit of a scale of inherent migratory aptitude that takes into account dynamic effects, both uphill and downhill ab initio molecular dynamics (AIMD) simulations were used to examine competing migration events in a model system designed to remove steric and electronic biases. The results of these simulations were combined with detailed investigations of potential energy surface topography and variational transition state theory calculations to reveal the importance of nonstatistical dynamic effects on migratory aptitude.

5.
Rheumatology (Oxford) ; 60(5): 2409-2420, 2021 05 14.
Artículo en Inglés | MEDLINE | ID: mdl-33246326

RESUMEN

OBJECTIVES: While myeloid-derived suppressor cells (MDSCs) were previously shown to promote a proinflammatory T helper (Th) 17 response in autoimmune conditions, a potential impact of the MDSC-Th17 immune axis on abnormal bone destruction in RA remains largely unknown. METHODS: We investigated the correlation between the frequency of MDSCs or its subsets and joint destruction in RA patients. The reciprocal actions of patient-derived MDSCs and Th17 cells were studied using osteoclast (OC) differentiation and bone resorption assays in vitro, which were further validated using mouse models of RA. Contribution of MDSCs to osteoclastogenesis and bone erosion in vivo was determined by depletion or transfer of MDSCs. RESULTS: Human MDSCs, particularly monocytic MDSCs (M-MDSCs), exhibit inherent OC-differentiating capacity and positively correlate with clinical bone erosion in RA patients. Strikingly, patient-derived M-MDSCs can program Th17 cells towards a pro-osteoclastogenic phenotype, which in return potentiates OC differentiation via the receptor activator of nuclear factor κΒ ligand (RANK-L)-RANK signalling. This enhanced osteolysis driven by the reciprocal actions of M-MDSCs and Th17 cells is further confirmed using mouse models of RA. Selective depletion of M-MDSCs significantly ameliorates osteoclastogenesis and disease severity in arthritic mice, whereas transfer of M-MDSCs aggravates bone erosion associated with increased OCs in recipient mice. CONCLUSION: Our findings highlight the functional plasticity of MDSCs and identify a novel pro-osteoclastogenic pathway governed by interplay between myeloid cells and T lymphocytes in autoimmune RA.


Asunto(s)
Artritis Reumatoide/inmunología , Resorción Ósea/inmunología , Monocitos/inmunología , Células Supresoras de Origen Mieloide/inmunología , Osteoclastos/inmunología , Células Th17/inmunología , Animales , Artritis Experimental/inmunología , Artritis Experimental/patología , Artritis Reumatoide/patología , Resorción Ósea/patología , Diferenciación Celular/inmunología , Humanos , Ratones , Fenotipo
6.
Angew Chem Int Ed Engl ; 59(8): 3058-3062, 2020 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-31821697

RESUMEN

We herein report a general organocatalytic enantioselective strategy for the construction of highly strained spiro[2,3]hexane skeletons from methylenecyclopropanes and a broad selection of α,ß-unsaturated aldehydes. The reaction proceeds through a Michael addition followed by ring expansion of methylenecyclopropanes and nucleophilic attack of an enamine to realize the construction of spiro[2,3]hexanes. Key to the success of this approach are the utilization of an electron-deficient difluoro-substituted secondary amine catalyst and the intrinsic reactivity of methylenecyclopropanes.

7.
J Org Chem ; 84(1): 60-72, 2019 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-30507130

RESUMEN

Herein, we describe a novel and efficient method for constructing a series of fluorine-containing γ-keto acid derivatives through combining visible-light photoredox catalysis and chiral Lewis acid catalysis. With this dual catalytic strategy, a variety of chiral γ-keto amides containing a gem-difluoroalkyl group and a series of fluorine-containing α,ß-unsaturated-γ-keto esters were successfully constructed with high stereoselectivities, respectively. A series of experiments showed that the chemoselectivity of this process was highly dependent on the fluorine reagents besides the Lewis acid catalysts. This approach facilitates rapid access to γ-keto acid derivatives, an important class of precursors for pharmaceuticals, plasticizers, and various other additives.

8.
Int J Mol Sci ; 21(1)2019 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-31878035

RESUMEN

Cerebral ischemia injury, the leading cause of morbidity and mortality worldwide, initiates sequential molecular and cellular pathologies that underlie ischemic encephalopathy (IE), such as ischemic stroke, Alzheimer disease (AD), Parkinson's disease (PD), epilepsy, etc. Targeted therapeutic treatments are urgently needed to tackle the pathological processes implicated in these neurological diseases. Recently, accumulating studies demonstrate that microRNA-124 (miR-124), the most abundant miRNA in brain tissue, is aberrant in peripheral blood and brain vascular endothelial cells following cerebral ischemia. Importantly, miR-124 regulates a variety of pathophysiological processes that are involved in the pathogenesis of age-related IE. However, the role of miR-124 has not been systematically illustrated. Paradoxically, miR-124 exerts beneficial effects in the age-related IE via regulating autophagy, neuroinflammation, oxidative stress, neuronal excitability, neurodifferentiation, Aß deposition, and hyperphosphorylation of tau protein, while it may play a dual role via regulating apoptosis and exerts detrimental effects on synaptic plasticity and axonal growth. In the present review, we thus focus on the paradoxical roles of miR-124 in age-related IE, as well as the underlying mechanisms. A great understanding of the effects of miR-124 on the hypoxic-ischemic brain will open new avenues for therapeutic approaches to protect against cerebral ischemia injury.


Asunto(s)
Apoptosis , Muerte Celular Autofágica , Lesiones Encefálicas/metabolismo , Isquemia Encefálica/metabolismo , MicroARNs/metabolismo , Estrés Oxidativo , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Animales , Lesiones Encefálicas/patología , Isquemia Encefálica/patología , Humanos , Accidente Cerebrovascular/metabolismo , Accidente Cerebrovascular/patología
9.
Chemistry ; 24(52): 13778-13782, 2018 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-30048022

RESUMEN

Due to the significance of hybrid systems in drug discovery, there is an urgent need to assemble multiple biologically active ingredients into a single molecule. Here, we report a general transition-metal-free selective C-H benzylation of tertiary arylamines in good to excellent yields with a broad substrate scope and high functional-group tolerance under mild conditions. Besides arylamines, some other benzene derivatives also readily furnished the corresponding diaryl methane derivatives with this protocol. A series of control experiments and theoretical calculations indicated that this transition-metal-free reaction is a dearomatization-aromatization process.

10.
Angew Chem Int Ed Engl ; 57(18): 5110-5114, 2018 04 23.
Artículo en Inglés | MEDLINE | ID: mdl-29473702

RESUMEN

Herein we describe a mild method for the dual C(sp3 )-H bond functionalization of saturated nitrogen-containing heterocycles through a sequential visible-light photocatalyzed dehydrogenation/[2+2] cycloaddition procedure. As a complementary approach to the well-established use of iminium ion and α-amino radical intermediates, the elusive cyclic enamine intermediates were effectively generated by photoredox catalysis under mild conditions and efficiently captured by acetylene esters to form a wide array of bicyclic amino acid derivatives, thus enabling the simultaneous functionalization of two vicinal C(sp3 )-H bonds.

11.
Clin Exp Rheumatol ; 35(3): 452-461, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28032844

RESUMEN

OBJECTIVES: Zaocys type II collagen is an active collagen extracted from Zaocys that has been used to treat rheumatoid arthritis in China for over 1000 years. However, the mechanism still remains unknown. Therefore, we set out to investigate the inhibitory effect and possible mechanism of action of zaocys type II collagen on collagen-induced arthritis. METHODS: Collagen-induced arthritis was induced in C57BL/6 mice by immunisation with type II collagen. After immunisation, the mice were treated with Zaocys type II collagen. Clinical and histological scores were assessed and the cytokine levels in the serum and lymphocytes supernatant from the spleen and mesenteric lymph node were determined by enzyme-linked immune sorbent assay. The T-helper 17 cell and regulatory-T cell frequencies were analysed by flow cytometry and the expression of interest markers was examined by direct immuno-fluorescence. RESULTS: The arthritis score and severity of histological inflammation and cartilage destruction were dose-dependently reduced after treatment. The analysis results indicated that Zaocys type II collagen significantly increased the proportion of regulatory-T cells and lowered the T-helper 17 cells, it also increased the number of regulatory-T cells and conversely decreased the T-helper 17 cells in synovial tissue compared with the model group. Treatment also caused a higher level of transforming growth factor-ß and a decreased production of interleukin -17A. CONCLUSIONS: The oral administration of Zaocys type II collagen potently suppressed the severity of collagen-induced arthritis by repairing the imbalance between regulatory-T cells and T-helper 17 cells, suggesting that it might be a promising candidate for the treatment of rheumatoid arthritis.


Asunto(s)
Antirreumáticos/farmacología , Artritis Experimental/prevención & control , Colágeno Tipo II/farmacología , Membrana Sinovial/efectos de los fármacos , Linfocitos T Reguladores/efectos de los fármacos , Células Th17/efectos de los fármacos , Administración Oral , Animales , Antirreumáticos/administración & dosificación , Artritis Experimental/sangre , Artritis Experimental/inducido químicamente , Artritis Experimental/inmunología , Colágeno Tipo II/administración & dosificación , Citocinas/sangre , Relación Dosis-Respuesta a Droga , Adyuvante de Freund , Mediadores de Inflamación/sangre , Ganglios Linfáticos/efectos de los fármacos , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/metabolismo , Masculino , Ratones Endogámicos C57BL , Índice de Severidad de la Enfermedad , Bazo/efectos de los fármacos , Bazo/inmunología , Bazo/metabolismo , Membrana Sinovial/inmunología , Membrana Sinovial/metabolismo , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/metabolismo , Células Th17/inmunología , Células Th17/metabolismo , Factores de Tiempo
12.
Ann Rheum Dis ; 75(1): 278-85, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25371442

RESUMEN

OBJECTIVES: Although myeloid-derived suppressor cells (MDSCs) have been linked to T cell tolerance, their role in autoimmune rheumatoid arthritis (RA) remains elusive. Here we investigate the potential association of MDSCs with the disease pathogenesis using a preclinical model of RA and specimen collected from patients with RA. METHODS: The frequency of MDSCs in blood, lymphoid tissues, inflamed paws or synovial fluid and their association with disease severity, tissue inflammation and the levels of pathogenic T helper (Th) 17 cells were examined in arthritic mice or in patients with RA (n=35) and osteoarthritis (n=15). The MDSCs in arthritic mice were also characterised for their phenotype, inflammation status, T cell suppressive activity and their capacity of pro-Th17 cell differentiation. The involvement of MDSCs in the disease pathology and a Th17 response was examined by adoptive transfer or antibody depletion of MDSCs in arthritic mice or by coculturing mouse or human MDSCs with naïve CD4+ T cells under Th17-polarising conditions. RESULTS: MDSCs significantly expanded in arthritic mice and in patients with RA, which correlated positively with disease severity and an inflammatory Th17 response. While displaying T cell suppressive activity, MDSCs from arthritic mice produced high levels of inflammatory cytokines (eg, interleukin (IL)-1ß, TNF-α). Mouse and human MDSCs promoted Th17 cell polarisation ex vivo. Transfer of MDSCs facilitated disease progression, whereas their elimination in arthritic mice ameliorated disease symptoms concomitant with reduction of IL-17A/Th17 cells. CONCLUSIONS: Our studies suggest that proinflammatory MDSCs with their capacity to drive Th17 cell differentiation may be a critical pathogenic factor in autoimmune arthritis.


Asunto(s)
Artritis Experimental/inmunología , Artritis Reumatoide/inmunología , Células Mieloides/inmunología , Subgrupos de Linfocitos T/inmunología , Animales , Enfermedades Autoinmunes/inmunología , Linfocitos T CD4-Positivos/inmunología , Diferenciación Celular/inmunología , Técnicas de Cocultivo , Progresión de la Enfermedad , Humanos , Tolerancia Inmunológica/inmunología , Masculino , Ratones Endogámicos C57BL , Osteoartritis/inmunología , Índice de Severidad de la Enfermedad , Líquido Sinovial/inmunología , Células Th17/inmunología
13.
BMC Musculoskelet Disord ; 15: 376, 2014 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-25403368

RESUMEN

BACKGROUND: Epidemiological studies have investigated the association between matrix metalloproteinase-3(MMP-3) gene-1171 5A/6A polymorphism and rheumatoid arthritis (RA), but the results were inconsistent. To evaluate the specific relationship, we performed a meta-analysis to clarify the controversies. METHODS: The relevant literatures dated to December 07th 2013 were retrieved from PubMed, EMBASE and the China National knowledge Infrastructure (CNKI) databases. The number of the alleles and genotypes for MMP-3 were obtained. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the association between MMP-3 5A/6A promoter polymorphism and RA. All of the statistical analyses were conducted by STATA11.0 software. RESULTS: A total of 6 case-control studies covering 1451 cases and 1239 controls were included in the final meta-analysis. There was no significant association between MMP-3 5A/6A promoter polymorphism and RA in all genetic models (for 6A versus 5A: OR=1.19, 95% CI=0.91-1.56, P=0.203; 5A/6A versus 5A/5A: OR=1.31, 95% CI=0.89-1.92, P=0.174; 6A/6A versus 5A/5A: OR=1.78, 95% CI=0.68-4.61, P=0.238; the recessive model: OR=1.48, 95% CI=0.88-2.47, P=0.141; and the dominant model: OR=1.46, 95% CI=0.71-3.00, P=0.299). In the subgroup analysis by ethnicity, we obtained the similar results. CONCLUSIONS: We systematically investigate the association between MMP-3-1171 5A/6A polymorphism and RA susceptibility; however, the results show a lack of correlation. Considering the small sample size and the selection bias existed in some studies, further studies are needed to confirm the findings.


Asunto(s)
Artritis Reumatoide/epidemiología , Artritis Reumatoide/genética , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad/genética , Metaloproteinasa 3 de la Matriz/genética , Polimorfismo Genético/genética , Artritis Reumatoide/diagnóstico , Estudios de Casos y Controles , Estudios de Asociación Genética/métodos , Predisposición Genética a la Enfermedad/epidemiología , Humanos
14.
Zhong Yao Cai ; 37(6): 1020-4, 2014 Jun.
Artículo en Zh | MEDLINE | ID: mdl-25470970

RESUMEN

OBJECTIVE: To analyze the homology of Zaocys type 1I collagen ( ZC II ) with the C II collagen from other species, and to investigate the effect of ZC II on arthritis in mice with collagen-induced arthritis (CIA). METHODS: ZC II was purified with restriction pepsin digestion. Then SDS-PAGE gel electrophoresis and UV spectrophotometry were used to identify the protein,the homology of the ZC II peptide was analyzed with Mass Spectrometry. The model of CIA mice were induced by subcutaneous injection of Chicken C II into male C57BL/6 mice from the base of the tails. After immunization,ZC II [H,M,L:40,20 and 10 µg/(kgd) ]was administered orally to mice from day 21 to 28 accordingly. The severity of the arthritis in each limb was evaluated using a macroscopic scoring system, and his- topathological change of joint was observed by light microscope with HE staining. RESULTS: The molecular weight of ZC II protein deter- mined by SDS-PAGE gel electrophoresis was between 110 kD and 140 kD, and UV absorption peak appeared at around 230 nm in wave- length. The peptide mass fingerprinting(PMF) of the purified protein by Mass Spectrometry analysis showed that it had at least 4 peptides matched with other species,and the protein score was greater than 95%. Compared with normal group,the CIA model group had significantly higher scores for arthritis and histopathological changes (P <0. 05). Meanwhile,the same scores for the ZC II peptide-treated mice with CIA were significantly lower than the mice from CIA model group(P <0. 05). CONCLUSION: Results of Mass Spectrometry analysis demonstrate that ZC II has high homology with the C II from other species. Oral administration of ZC II can suppress arthritis in mice with CIA and ameliorate the histopathological changes of the joint.


Asunto(s)
Artritis Experimental/tratamiento farmacológico , Colágeno Tipo II/uso terapéutico , Animales , Artritis , Artritis Experimental/inducido químicamente , Electroforesis en Gel de Poliacrilamida , Articulaciones , Masculino , Ratones , Ratones Endogámicos C57BL
15.
Front Pharmacol ; 15: 1352760, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38487170

RESUMEN

Cerebral ischemia/reperfusion injury (CIRI) is a major contributor to poor prognosis of ischemic stroke. Flavonoids are a broad family of plant polyphenols which are abundant in traditional Chinese medicine (TCM) and have beneficial effects on several diseases including ischemic stroke. Accumulating studies have indicated that flavonoids derived from herbal TCM are effective in alleviating CIRI after ischemic stroke in vitro or in vivo, and exhibit favourable therapeutical potential. Herein, we systematically review the classification, metabolic absorption, neuroprotective efficacy, and mechanisms of TCM flavonoids against CIRI. The literature suggest that flavonoids exert potential medicinal functions including suppressing excitotoxicity, Ca2+ overloading, oxidative stress, inflammation, thrombin's cellular toxicity, different types of programmed cell deaths, and protecting the blood-brain barrier, as well as promoting neurogenesis in the recovery stage following ischemic stroke. Furthermore, we identified certain matters that should be taken into account in future research, as well as proposed difficulties and opportunities in transforming TCM-derived flavonoids into medications or functional foods for the treatment or prevention of CIRI. Overall, in this review we aim to provide novel ideas for the identification of new prospective medication candidates for the therapeutic strategy against ischemic stroke.

16.
J Ethnopharmacol ; 333: 118422, 2024 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-38838922

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese herbal medicine Panax japonicus C.A. Meyer has a long history in clinical treatment of rheumatoid arthritis (RA). Total saponins of Panax japonicus C.A. Meyer (TSPJs) were extracted from the root of Panax japonicus C.A. Meyer, and its anti-rheumatism mechanism is still unclear. AIM OF THE STUDY: To investigate whether TSPJs attenuated synovial angiogenesis in RA and explore the potential mechanisms. MATERIALS AND METHODS: Potential TSPJs targets involving gene function were predicted by network pharmacology related databases. Bioinformatics analysis and molecular docking technology were used to predict the mechanism of TSPJs in the treatment of RA. The predicted results were validated by cell experiments and a collagen-induced arthritis (CIA) mouse model. RESULTS: Bioinformatics analysis results showed that TSPJs may inhibit RA-related angiogenesis through the hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) pathways. In vitro, different doses of TSPJs showed a good inhibitory effect on the tube formation of EA.hy926 cells. The results of the cellular thermal shift assay indicated that TSPJs can bind to the HIF-1α, VEGFA, and angiopoietin-1 (ANG-1) proteins. In vivo, the administration of TSPJs alleviated the symptoms of CIA mice, including the arthritis index, hind paw thickness, and swollen joint count. The histological results demonstrated that TSPJs inhibited inflammation, angiogenesis, bone damage, and cartilage destruction. Furthermore, TSPJs decreased the number of vessels and the expression level of CD31. The mechanistic results revealed that TSPJs decreased the expression of HIF-1α, VEGFA, and ANG-1 in the serum or synovial tissues of CIA mice. CONCLUSION: These results suggest that TSPJs effectively inhibit angiogenesis in RA, and the mechanism may be related to inhibiting the HIF-1α/VEGF/ANG-1 axis.


Asunto(s)
Inhibidores de la Angiogénesis , Angiopoyetina 1 , Artritis Experimental , Artritis Reumatoide , Subunidad alfa del Factor 1 Inducible por Hipoxia , Panax , Saponinas , Factor A de Crecimiento Endotelial Vascular , Animales , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Saponinas/farmacología , Saponinas/uso terapéutico , Artritis Reumatoide/tratamiento farmacológico , Factor A de Crecimiento Endotelial Vascular/metabolismo , Panax/química , Artritis Experimental/tratamiento farmacológico , Artritis Experimental/patología , Humanos , Inhibidores de la Angiogénesis/farmacología , Masculino , Ratones , Angiopoyetina 1/metabolismo , Simulación del Acoplamiento Molecular , Ratones Endogámicos DBA , Neovascularización Patológica/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Raíces de Plantas/química
17.
Nat Chem ; 16(4): 615-623, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38216753

RESUMEN

Revealing the origins of kinetic selectivity is one of the premier tasks of applied theoretical organic chemistry, and for many reactions, doing so involves comparing competing transition states. For some reactions, however, a single transition state leads directly to multiple products, in which case non-statistical dynamic effects influence selectivity control. The selectivity of photochemical reactions-where crossing between excited-state and ground-state surfaces occurs near ground-state transition structures that interconvert competing products-also should be controlled by the momentum of the reacting molecules as they return to the ground state in addition to the shape of the potential energy surfaces involved. Now, using machine-learning-assisted non-adiabatic molecular dynamics and multiconfiguration pair-density functional theory, these factors are examined for a classic photochemical reaction-the deazetization of 2,3-diazabicyclo[2.2.2]oct-2-ene-for which we demonstrate that momentum dominates the selectivity for hexadiene versus [2.2.2] bicyclohexane products.

18.
Sci Total Environ ; 864: 161109, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36566859

RESUMEN

Being an important theme in global warming, the response of vegetation phenology to urbanization has become an increasing concern at both the local and global levels. Previous studies have focused on spatial or temporal responses across urban-rural gradients; thus, the influence of urbanization on vegetation phenology along the dynamic urbanization gradient has not been well quantified. In this study, we comprehensively analyzed the response of vegetation phenology to urbanization in the Guangdong-Hong Kong-Macao Greater Bay Area (GHM-GBA) from a dynamic urban-rural gradient perspective. The results show that the response of vegetation phenology to urbanization level has a distinct spatiotemporal difference across the urban-rural gradient. Compared to rural areas, the change rate of advancements in the start-of-season (SOS) in urban domains was 1.16 DOY/year and that of the end-of-season (EOS) was 0.63 days/year from 2001 to 2020. In the GHM-GBA region, 61.03 % of the remote sensing pixels showed an advancing trend for SOS and 55.75 % for EOS. Urbanization advanced the SOS and EOS but did not extend the growing season length, and the SOS and EOS were advanced by 7 and 6 days along the urban-to-rural gradient, respectively. For every 10 % increase in urbanization levels, the SOS and EOS advanced by 1.085 and 1.091 days across the urban-rural gradient, respectively; the spring land surface temperature (LST) advanced the SOS at a rate of 1.71 days/°C, while the autumn LST advanced the EOS at a rate of 1.88 days/°C. The phenological shift in the urban-rural gradient was more significant than that over time, which was mainly because of land surface warming under different urbanization levels. These quantitative findings are of great importance for understanding the complicated impacts of urbanization on vegetation phenology and for developing models to predict vegetation phenological changes under future urbanization.


Asunto(s)
Calentamiento Global , Urbanización , Estaciones del Año , Temperatura , Hong Kong
19.
Heliyon ; 9(8): e19232, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37664720

RESUMEN

Objective: Chaihu-Shugan-San (CSS) is a traditional Chinese medicine formula employed to treat depression. We aim to conduct a reporting quality assessment and risk of bias evaluation of animal research on CSS for depression. Methods: To acquire eligible studies, two reviewers searched plentiful databases from inception to October 23rd, 2021. Reporting quality assessment and risk of bias assessment of the included animal studies were evaluated by using Animal Research: Reporting In Vivo Experiments (ARRIVE) guidelines and the SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) risk of bias tool, respectively. Results: The initial search identified 720 records, while only 30 studies were included. The result of the reporting quality assessment was inferior, items 17 and 19 were not reported at all. The details of five items (items 3, 6, 7, 10, and 18) were not reported. The outcome of the risk of bias assessment suggested that half of the entries (5/10) displayed an unclear risk of bias and a high risk of bias. Blinding with regard to performance bias and detection bias revealed an unclear risk of bias (100%), followed by baseline characteristics (76.67%) and sequence generation (60%). Random outcome assessment showed a high risk of bias (100%). Conclusion: The included animal studies exhibited methodological defects and imprecise reporting. Hence, the ARRIVE guidelines and SYRCLE's RoB tool should be disseminated among basic medical researchers examining CSS for depression to publish studies with low risk of bias and sufficient reporting so that the animal research can promptly be transformed into clinical research.

20.
BMC Complement Med Ther ; 23(1): 37, 2023 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-36747185

RESUMEN

OBJECTIVE: A multicriteria decision analysis (MCDA) model was used to evaluate the benefits and risks of traditional Chinese medicine preparations of sinomenine alone or in combination with conventional drugs in the treatment of rheumatoid arthritis (RA) and to provide a basis for the rational clinical application of sinomenine. METHODS: A study search was performed using six major databases, and Review Manager 5.3 was used for data analysis. Then, an MCDA model evaluation system was established for the treatment of RA with sinomenine preparations, and the benefit values, risk values, and total benefit-risk values of sinomenine preparations alone or in combination with conventional drugs were calculated using Hiview 3.2 software. Finally, Monte Carlo simulations were performed using Crystal Ball embedded in Excel software to calculate the 95% confidence intervals (95% CI), and the probability of the differences between the 2 drug regimens was determined to optimize the evaluation results. RESULTS: Forty-four randomized controlled trials (RCTs) were included. Quantitative assessment of the MCDA model showed that the sinomenine preparation alone offered less benefits than when combined with conventional drugs with a benefit difference of 20 (95% CI 3.06, 35.71). However, the risk of the combination was significantly lower with a risk difference of 13(95% CI -10.26, 27.52). The total value of the benefit-risk of sinomenine alone and in combination with conventional drugs was 46 and 53 at 60% and 40% of the benefit-risk ratio of the two dosing regimens, respectively, with a difference of 7 (95% CI -4.26, 22.12). The probability that the comprehensive score of the combined regimen is greater than that of sinomenine alone is 90.1%, and the evaluation was steady. CONCLUSION: The benefit-risk of the combined application regimen of sinomenine is greater than that of sinomenine alone.


Asunto(s)
Artritis Reumatoide , Medicina Tradicional China , Humanos , Artritis Reumatoide/tratamiento farmacológico , Técnicas de Apoyo para la Decisión , Medición de Riesgo
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