Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Front Nutr ; 10: 1268436, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37955019

RESUMEN

Background: Excessive consumption of sugar-sweetened beverages (SSBs) is associated with increased risks of obesity and chronic diseases. To effectively control SSB consumption, several countries including Mexico, France, and the United Kingdom have implemented SSB taxes. However, research on SSB taxes in China is limited. Objective: To assess the attitudes of Chinese residents toward the SSB tax and their willingness to pay the tax. Methods: Data were collected through a questionnaire survey among 881 respondents. The generalized ordered logit regression model and marginal effect analysis were used to analyze Chinese participants' attitudes toward SSB tax and their willingness to pay it. Results: The average monthly expenditure on SSBs was 44.8 ± 45.3 Yuan (RMB) (6.95 ± 7.02$), and 54.6% of residents supported the SSB tax; they were willing to pay, on average, 1.19 times the original price after additional tax. Age, physical exercise, self-rated health status, weight control plan, awareness of SSBs, children's consumption of SSBs, and proximity to the nearest SSB outlet significantly influenced attitudes toward tax. Notably, SSB awareness had the greatest effect on tax attitudes, with a 17% increase in the probability of supporting SSB tax for every one-level increase in SSB awareness among residents. Conclusion: Residents in China have attained a certain level of awareness of, support for, and willingness to pay SSB tax. However, promoting knowledge about the health effects of SSBs and conducting further research to evaluate the effect of SSB tax on obesity prevention in China is still essential.

2.
Org Biomol Chem ; 21(27): 5511-5515, 2023 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-37350096

RESUMEN

Herein, a visible light-induced synthesis of polysubstituted oxazoles from diazo compounds is reported. This developed synthetic method differs from traditional routes that rely on transition metals and external chemical oxidants. Our method uses readily available and inexpensive diazonium compounds as well as nitrile substrates with a catalytic amount of (i-Pr)3SiCl species, delivering the corresponding valuable multi-substituted oxazole products (up to 95% yield). This protocol exhibits a broad substrate scope and is easily carried out under mild reaction conditions. Notably, gram-scale synthesis in a continuous flow fashion has been performed.

3.
Org Lett ; 25(14): 2410-2414, 2023 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-36996439

RESUMEN

A visible-light-induced trifluoromethylsulfonylation reaction of diazo compounds is herein reported. This developed synthetic method captures the relatively rare trifluoromethyl sulfone radicals via coordination to the Mn(acac)3 catalyst, delivering the corresponding α-trifluoromethyl sulfone esters in good to moderate yields (up to 82%). This protocol exhibits broad substrate scope and is easily carried out under mild reaction conditions. Furthermore, a plausible mechanism of the reaction was investigated through DFT calculations.

4.
Org Lett ; 25(3): 506-511, 2023 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-36637222

RESUMEN

A versatile photochemical ring-expansion protocol for the synthesis of oxacyclic spirooxindoles under catalyst-free conditions is described. The reaction is enabled by the use of unstrained O-containing heterocycles with 3-diazoindolin-2-ones under visible-light irradiation. Several synthetic advantages for this method are exhibited, including mild conditions, good functional group tolerance, operational simplicity, and scalability. Mechanistic studies indicate that the transformation may proceed through the formation of oxonium ylide intermediate followed by an ionic cyclization.

5.
J Exp Bot ; 73(1): 123-138, 2022 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-34490889

RESUMEN

The formation of locule gel is an important process in tomato and is a typical characteristic of berry fruit. In this study, we examined a natural tomato mutant that produces all-flesh fruit (AFF) in which the locule tissue remains in a solid state during fruit development. We constructed different genetic populations to fine-map the causal gene for this trait and identified SlMBP3 as the locus conferring the locule gel formation, which we rename as AFF. We determined the causal mutation as a 416-bp deletion in the promoter region of AFF, which reduces its expression dosage. Generally, this sequence is highly conserved among Solanaceae, as well as within the tomato germplasm. Using BC6 near-isogenic lines, we determined that the reduced expression dosage of AFF did not affect the normal development of seeds, whilst producing unique, non-liquefied locule tissue that was distinct from that of normal tomatoes in terms of metabolic components. Combined analysis using mRNA-seq and metabolomics indicated the importance of AFF in locule tissue liquefaction. Our findings provide insights into fruit-type differentiation in Solanaceae crops and also present the basis for future applications of AFF in tomato breeding programs.


Asunto(s)
Solanum lycopersicum , Frutas/genética , Solanum lycopersicum/genética , Mutación , Fitomejoramiento , Regiones Promotoras Genéticas
6.
Plant Dis ; 105(4): 851-858, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33021912

RESUMEN

Late blight is a devastating tomato disease. Breeding new varieties with multiple resistance (R) genes is highly effective for preventing late blight. The Ph-2 gene mediates resistance to Phytophthora infestans race T1 in tomato. In this study, we used an F2 population derived from a cross between Solanum lycopersicum Moboline (resistant) and LA3988 (susceptible) cultivars for the fine mapping of Ph-2. Two flanking markers, CAPS-1 and CC-Ase, mapped Ph-2 to a 141-kb genomic region containing 21 projected genes, 5 of which were identified as putative R genes. The Solyc10g085460 coding sequence varied significantly between the parents. The markers developed and candidate genes identified in this study shall be useful for the molecular breeding of tomato exhibiting increased late blight resistance and for the cloning of the Ph-2 gene.


Asunto(s)
Phytophthora infestans , Solanum lycopersicum , Resistencia a la Enfermedad/genética , Humanos , Solanum lycopersicum/genética , Fitomejoramiento , Enfermedades de las Plantas/genética
7.
Pest Manag Sci ; 76(11): 3806-3821, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32483849

RESUMEN

BACKGROUND: Cultivated tomatoes are highly susceptible to the destructive parasite Phelipanche aegyptiaca. Wild relatives show the potential resistance for genetic improvement. However, their genetic and molecular mechanisms are still unknown. RESULTS: Among 50 wild tomato accessions were evaluated for resistance to P. aegyptiaca, most of the wild relatives exhibited varying degrees of resistance compared to the cultivars. Solanum pennellii LA0716 performed the most promising and solid resistance with very low infection by the broomrape. The resistance involved in LA0716 was further confirmed by cytological analysis, and explored by employing a permanent introgression line (IL) population. Thirteen putative quantitative trait loci (QTLs) conferring the different resistance traits were identified. They are located on chromosomes 1, 2, 3, 4, 6, 8 and 9. The most attractive QTLs are positioned in IL6-2 and overlap with IL6-3. Specially, IL6-2 showed the highest and most consistent resistance for multiple traits and explained the major phenotypic variation of LA0716. Analysis of candidate genes involved in these regions showed that Beta (Solyc06g074240) and P450 (Solyc06g073570, Solyc06g074180 and Solyc06g074420) genes are substantially related to the strigolactone (SL) pathway. Transcript analysis further demonstrated that both Solyc06g073570 and Solyc06g074180 might play an important role in the reduction of P. aegyptiaca infection. CONCLUSION: Germplasms resistant to P. aegyptiaca were found in wild tomato species. QTLs conferring P. aegyptiaca tolerance in LA0716 were identified. IL6-2 is identified as a prospective line possessing the major QTLs. The candidate genes would provide the availability to assist the introgression of the resistance in future breeding programmes. © 2020 Society of Chemical Industry.


Asunto(s)
Solanum lycopersicum , Solanum lycopersicum/genética , Orobanche , Estudios Prospectivos , Sitios de Carácter Cuantitativo , Solanum
8.
Int J Mol Sci ; 20(9)2019 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-31060285

RESUMEN

Internode length is an important agronomic trait affecting plant architecture and crop yield. However, few genes for internode elongation have been identified in tomato. In this study, we characterized an elongated internode inbred line P502, which is a natural mutant of the tomato cultivar 05T606. The mutant P502 exhibits longer internode and higher bioactive GA concentration compared with wild-type 05T606. Genetic analysis suggested that the elongated internode trait is controlled by quantitative trait loci (QTL). Then, we identified a major QTL on chromosome 2 based on molecular markers and bulked segregant analysis (BSA). The locus was designated as EI (Elongated Internode), which explained 73.6% genetic variance. The EI was further mapped to a 75.8-kb region containing 10 genes in the reference Heinz 1706 genome. One single nucleotide polymorphism (SNP) in the coding region of solyc02g080120.1 was identified, which encodes gibberellin 2-beta-dioxygenase 7 (SlGA2ox7). SlGA2ox7, orthologous to AtGA2ox7 and AtGA2ox8, is involved in the regulation of GA degradation. Overexpression of the wild EI gene in mutant P502 caused a dwarf phenotype with a shortened internode. The difference of EI expression levels was not significant in the P502 and wild-type, but the expression levels of GA biosynthetic genes including CPS, KO, KAO, GA20ox1, GA20ox2, GA20ox4, GA3ox1, GA2ox1, GA2ox2, GA2ox4, and GA2ox5, were upregulated in mutant P502. Our results may provide a better understanding of the genetics underlying the internode elongation and valuable information to improve plant architecture of the tomato.


Asunto(s)
Estudios de Asociación Genética , Proteínas de Plantas/genética , Sitios de Carácter Cuantitativo , Carácter Cuantitativo Heredable , Solanum lycopersicum/genética , Clonación Molecular , Regulación de la Expresión Génica de las Plantas , Endogamia , Solanum lycopersicum/metabolismo , Redes y Vías Metabólicas/genética , Mutación , Filogenia
9.
J Nanosci Nanotechnol ; 7(4-5): 1268-83, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17450890

RESUMEN

Optical limiting is an important application of nonlinear optics, useful for the protection of human eyes, optical elements, and optical sensors from intense laser pulses. An optical limiter is such a device that strongly attenuates high intensity light and potentially damaging light such as focused laser beams, whilst allowing for the high transmission of ambient light. Optical limiting properties of carbon nanotube suspensions, solubilized carbon nanotubes, small molecules doped carbon nanotubes and polymer/carbon nanotube composites have been reviewed. The optical limiting responses of carbon nanotube suspensions are shown to be dominated by nonlinear scattering as a result of thermally induced solvent-bubble formation and sublimation of the nanotubes, while the solubilized carbon nanotubes optically limit through nonlinear absorption mechanism and exhibit significant solution-concentration-dependent optical limiting responses. In the former case the optical limiting results are independent of nanotube concentrations at the same linear transmittance as that of the solubilized systems. Many efforts have been invested into the research of polymer/carbon nanotube composites in an attempt to allow for the fabrication of films required for the use of nanotubes in a real optical limiting application. The higher carbon nanotube content samples block the incident light more effectively at higher incident energy densities or intensities. The optical limiting mechanism of these composite materials is quite complicated. Besides nonlinear scattering contribution to the optical limiting, there may also be other contributions e.g., nonlinear absorption, nonlinear refraction, electronic absorption and others to the optical limiting. Further improvements in the optical limiting efficiency of the composites and in the dispersion and alignment properties of carbon nanotubes in the polymer matrix could be realized by variation of both nanostructured guest and polymer host, and by ex situ alignment and other methods. It would be very desirable, from the practical application point of view, if one can design broadband optical limiting chromophores that would function in a multimechanistic fashion.


Asunto(s)
Biofisica/métodos , Carbono/química , Nanotecnología/métodos , Nanotubos de Carbono/química , Absorción , Electrónica , Fulerenos/química , Luz , Microscopía Electrónica de Rastreo , Modelos Moleculares , Nanotubos/química , Óptica y Fotónica , Polímeros/química , Dispersión de Radiación
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...