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1.
World J Clin Cases ; 12(1): 86-94, 2024 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-38292647

RESUMO

BACKGROUND: The obesity rate of adolescents is gradually increasing, which seriously affects their mental health, and sleep plays an important role in adolescent obesity. AIM: To investigate the relationship between sleep rhythm and obesity among adolescents and further explores the interactive effect of sleep rhythm and gender on adolescent obesity, providing a theoretical basis for developing interventions for adolescent obesity. METHODS: Research data source Tianjin Mental Health Promotion Program for Students. From April to June 2022, this study selected 14201 students from 13 middle schools in a certain district of Tianjin as the research subject using the convenient cluster sampling method. Among these students, 13374 accepted and completed the survey, with an effective rate of 94.2%.The demographic data and basic information of adolescents, such as height and weight, were collected through a general situation questionnaire. The sleep rhythm of adolescents was evaluated using the reduced version of the morningness-eveningness questionnaire. RESULTS: A total of 13374 participants (6629 females, accounting for 49.56%; the average age is 15.21 ± 1.433 years) were analyzed. Among them, the survey showed that 2942 adolescent were obesity, accounting for 22% and 2104 adolescent were overweight, accounting for 15.7%. Among them, 1692 male adolescents are obese, with an obesity rate of 25.1%, higher than 18.9% of female adolescents. There is a statistically significant difference between the three groups (χ2 = 231.522, P < 0.000). The obesity group has the smallest age (14.94 ± 1.442 years), and there is a statistical difference in age among the three groups (F = 69.996, P < 0.000).Obesity rates are higher among individuals who are not-only-child, have residential experience within six months, have family economic poverty, and have evening-type sleep (P < 0.05). Logistic regression analysis shows a correlation between sleep rhythm and adolescent obesity. Evening-type sleep rhythm can increase the risk of obesity in male adolescents [1.250 (1.067-1.468)], but the effect on female obesity is not remarkable. Further logistic regression analysis in the overall population demonstrates that the interaction between evening-type sleep rhythm and the male gender poses a risk of adolescent obesity [1.122 (1.043-1.208)]. CONCLUSION: Among adolescents, the incidence of obesity in males is higher than in females. Evening-type sleep rhythm plays an important role in male obesity but has no significant effect on female obesity. Progressive analysis suggests an interactive effect of sleep rhythm and gender on adolescent obesity, and the combination of evening-type sleep and the male gender promotes the development of adolescent obesity. In formulating precautions against adolescent obesity, obesity in male adolescents with evening-type sleep should be a critical concern.

2.
Microorganisms ; 11(3)2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-36985348

RESUMO

Many wild ornamental plant species have been introduced to improve the landscape of cities; however, until now, no study has been performed to explore the composition and function of foliar endophytes associated with cultivated rare plants in cities after their introduction. In this study, we collected the leaves of the healthy ornamental plant Lirianthe delavayi from wild and artificially cultivated habitats in Yunnan and compared their diversity, species composition, and functional predictions of their foliar endophytic fungal community based on high-throughput sequencing technology. In total, 3125 ASVs of fungi were obtained. The alpha diversity indices of wild L. delavayi populations are similar to those of cultivated samples; however, the species compositions of endophytic fungal ASVs were significantly varied in the two habitats. The dominant phylum is Ascomycota, accounting for more than 90% of foliar endophytes in both populations; relatively, artificial cultivation trends to increase the frequency of common phytopathogens of L. delavayi, such as Alternaria, Erysiphe. The relative abundance of 55 functional predictions is different between wild and cultivated L. delavayi leaves (p < 0.05); in particular, chromosome, purine metabolism, and peptidases are significantly increased in wild samples, while flagellar assembly, bacterial chemotaxis, and fatty acid metabolism are significantly enhanced in cultivated samples. Our results indicated that artificial cultivation can greatly change the foliar endophytic fungal community of L. delavayi, which is valuable for understanding the influence of the domestication process on the foliar fungal community associated with rare ornamental plants in urban environments.

3.
Zhongguo Ying Yong Sheng Li Xue Za Zhi ; 38(2): 97-101, 2022 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-36031564

RESUMO

Objective: To study the effects of Synaptotagmin1 gene knockout (Syt1+/-) on emotional behavior in mice and explore its possible mechanisms. Methods: Five 8-week-old male Syt1+/-mice and five wild-type (WT) mice in the same litter were selected. The expressions of Syt1 in 6 mice brain regions of prelimbic cortex (PL), hippocampus (HIP), amygdala (AMY), accumbens nucleus (ACB), caudoputamen (CP) and ventral tegmental area (VTA) were detected by Immunofluorescence staining. Nine 8-week-old male Syt1+/-mice and ten WT mice were selected as controls. The anxiety-like behaviors of adult Syt1+/- mice and WT mice were detected by open field test, elevated plus maze test and forced swim test. In addition, five 8-week-old male Syt1+/-mice and five WT mice were selected to detect the glutamate content in prelimbic cortex, hippocampus and amygdala. Results: Compared with WT mice, the number of Syt1 positive cells in PL, HIP, AMY, ACB, CP and VTA were decreased significantly in Syt1+/- mice (P<0.01); Syt1+/- mice had less total movement distance in open field test (P<0.01), more preference for peripheral area (P<0.01) and less desire to explore the central platform (P<0.01), while Syt1+/- mice preferred to stay in a closed and safe environment (P<0.01); the number (P<0.05) and the time spent in open-arm explorations (P<0.01) were reduced significantly; the immobile time of Syt1+/- mice was increased in the forced swim test (P<0.01). Meanwhile, the concentration of glutamate in the amygdala of Syt1+/- mice was increased significantly (P<0.01). Conclusion: Syt1 gene knockout leads to significant anxiety-like behavior in mice, which is deduced that related to the increase of glutamate content in the amygdala.


Assuntos
Tonsila do Cerebelo , Ansiedade , Animais , Comportamento Animal , Técnicas de Inativação de Genes , Ácido Glutâmico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
4.
Curr Med Sci ; 42(5): 981-990, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35896932

RESUMO

OBJECTIVE: Epidemiology studies indicate that green tea polyphenols (GTP) perform a protective effect on cardiovascular diseases, but the underlying mechanisms are complex. The present study aimed to investigate the effect of GTP on high-fat diets (HFD) induced-early vascular aging. METHODS: Six-week young adult Wistar rats were fed with standard chow or HFD in the presence and absence of GTP (200 mg/kg body weight) for 18 weeks. In vitro experiment, human umbilical vascular endothelial cells (HUVECs) were treated with palmitic acid (PA) and GTP. RESULTS: The results showed that GTP alleviated the disorganized arterial wall and the increased intima-media thickness induced by HFD. In addition, the vascular oxidative injury was suppressed following GTP treatment. Furthermore, GTP elevated the ratio of LC3-II/LC3-I and suppressed expression of p62/SQSTM1, and restored SIRT3 expression in the aorta of HFD rats. Consistently, in cultured HUVECs, GTP inhibited cell senescence indicated by SA-ß-gal and promoted endothelial autophagy compared with the PA treatment group. The activity of SIRT3 was specifically inhibited by 3-TYP, and the protective effect of GTP was consequently abolished. CONCLUSION: The findings indicated that GTP protected against early vascular senescence in young HFD rats via ameliorating oxidative injury and promoting autophagy which was partially regulated by the SIRT3 pathway.


Assuntos
Dieta Hiperlipídica , Sirtuína 3 , Animais , Ratos , Envelhecimento , Antioxidantes/farmacologia , Autofagia , Espessura Intima-Media Carotídea , Dieta Hiperlipídica/efeitos adversos , Células Endoteliais/metabolismo , Guanosina Trifosfato/farmacologia , Ácido Palmítico/farmacologia , Polifenóis/farmacologia , Ratos Wistar , Proteína Sequestossoma-1/metabolismo , Sirtuína 3/metabolismo , Sirtuína 3/farmacologia , Chá/metabolismo
5.
J Matern Fetal Neonatal Med ; 34(10): 1557-1564, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-31269844

RESUMO

BACKGROUND: Recently, gestational diabetes mellitus (GDM) exhibits an obvious trend of increase in pregnant mothers and usually causes several abnormities or diseases for the offspring. Although several studies have been reported for potential molecular mechanisms, relevant genes or mutated sites have not been intensively investigated in China. MATERIALS AND METHODS: In the present study, 218 pregnant mothers (GDM group: 103 individuals and control group: 115 individuals) in China were enrolled to conduct genome-wide association study (GWAS) and pathway analyses for the purpose of related genes associated with GDM in China. RESULTS: Our results identified 23 SNPs exhibiting closely association with GDM using multiple tests. Annotation of these 23 SNPs identified four genes (SYNPR, CDH18, CTIF, and PTGIS), which suggests that the four genes may associate with GDM. GO enrichment and KEGG pathway analysis showed that gene SYNPR, CDH18, and PTGIS were enriched or located into the pathways or process associated with glycometabolism (e.g. insulin resistance and glucose tolerance), which further indicates that the three genes may associate with the GDM. CONCLUSION: The identification of these potential genes associating with GDM enriched the potential molecular mechanisms of GDM in Asia and will provide abundant stocks for subsequent clinical verifications for better understanding the molecular mechanisms, diagnosis, drug development and clinical treatment of GDM.


Assuntos
Diabetes Gestacional , Resistência à Insulina , China/epidemiologia , Diabetes Gestacional/epidemiologia , Diabetes Gestacional/genética , Feminino , Estudo de Associação Genômica Ampla , Humanos , Polimorfismo de Nucleotídeo Único , Gravidez
6.
BMC Plant Biol ; 20(1): 294, 2020 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-32600265

RESUMO

BACKGROUND: Catechins, caffeine, and theanine as three important metabolites in the tea leaves play essential roles in the formation of specific taste and shows potential health benefits to humans. However, the knowledge on the dynamic changes of these metabolites content over seasons, as well as the candidate regulatory factors, remains largely undetermined. RESULTS: An integrated transcriptomic and metabolomic approach was used to analyze the dynamic changes of three mainly metabolites including catechins, caffeine, and theanine, and to explore the potential influencing factors associated with these dynamic changes over the course of seasons. We found that the catechins abundance was higher in Summer than that in Spring and Autumn, and the theanine abundance was significantly higher in Spring than that in Summer and Autumn, whereas caffeine exhibited no significant changes over three seasons. Transcriptomics analysis suggested that genes in photosynthesis pathway were significantly down-regulated which might in linkage to the formation of different phenotypes and metabolites content in the tea leaves of varied seasons. Fifty-six copies of nine genes in catechins biosynthesis, 30 copies of 10 genes in caffeine biosynthesis, and 12 copies of six genes in theanine biosynthesis were detected. The correlative analysis further presented that eight genes can be regulated by transcription factors, and highly correlated with the changes of metabolites abundance in tea-leaves. CONCLUSION: Sunshine intensity as a key factor can affect photosynthesis of tea plants, further affect the expression of major Transcription factors (TFs) and structural genes in, and finally resulted in the various amounts of catechins, caffeine and theaine in tea-leaves over three seasons. These findings provide new insights into abundance and influencing factors of metabolites of tea in different seasons, and further our understanding in the formation of flavor, nutrition and medicinal function.


Assuntos
Cafeína/biossíntese , Camellia sinensis/metabolismo , Catequina/biossíntese , Glutamatos/biossíntese , Expressão Gênica , Metabolômica , Fenótipo , Folhas de Planta/metabolismo , Estações do Ano , Fatores de Transcrição/metabolismo , Transcriptoma
7.
Front Microbiol ; 10: 1419, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31293550

RESUMO

Controlling aflatoxigenic Aspergillus flavus and aflatoxins (AFs) in grains and food during storage is a great challenge to humans worldwide. Alcaligenes faecalis N1-4 isolated from tea rhizosphere soil can produce abundant antifungal volatiles, and greatly inhibited the growth of A. flavus in un-contacted face-to-face dual culture testing. Gas chromatography tandem mass spectrometry revealed that dimethyl disulfide (DMDS) and methyl isovalerate (MI) were two abundant compounds in the volatile profiles of N1-4. DMDS was found to have the highest relative abundance (69.90%, to the total peak area) in N1-4, which prevented the conidia germination and mycelial growth of A. flavus at 50 and 100 µL/L, respectively. The effective concentration for MI against A. flavus is 200 µL/L. Additionally, Real-time quantitative PCR analysis proved that the expression of 12 important genes in aflatoxin biosynthesis pathway was reduced by these volatiles, and eight genes were down regulated by 4.39 to 32.25-folds compared to control treatment with significant differences. And the A. flavus infection and AFs contamination in groundnut, maize, rice and soybean of high water activity were completely inhibited by volatiles from N1-4 in storage. Scanning electron microscope further proved that A. flavus conidia inoculated on peanuts surface were severely damaged by volatiles from N1-4. Furthermore, strain N1-4 showed broad and antifungal activity to other six important plant pathogens including Fusarium graminearum, F. equiseti, Alternaria alternata, Botrytis cinerea, Aspergillus niger, and Colletotrichum graminicola. Thus, A. faecalis N1-4 and volatile DMDS and MI may have potential to be used as biocontrol agents to control A. flavus and AFs during storage.

8.
Biochem Biophys Res Commun ; 504(2): 470-477, 2018 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-30195493

RESUMO

Gestational diabetes mellitus (GDM) is a type of diabetes and occurs during pregnancy. Brown adipose tissue (BAT) improves glucose homeostasis and mitigates insulin resistance, however, its activity is reduced in GDM. Placenta growth factor (PlGF) is an angiogenic factor produced by placental trophoblasts. Nevertheless, whether and how PlGF could affect BAT function in GDM are not defined. To investigate this question, 91 non-diabetic pregnant participants and 73 GDM patients were recruited to Gynaecology and Obstetrics Centre in Lu He hospital. Serum levels of PlGF were quantified by ELISA. Skin temperature was measured by far infrared thermography in the supraclavicular region where classical BATs were located. The direct effect of PlGF on BAT function was explored using the established human preadipocyte differentiation system. Thereby, we demonstrated that serum levels of PlGF were lower in GDM patients compared with controls, which was accompanied by decreased skin temperature in the supraclavicular region. By qPCR and western blot, mRNA and protein expression of UCP1 and OXPHOS were elevated in differentiated adipocytes treated with PlGF. PlGF stimulated mitochondrion transcription and increased copy number of mitochondrial. When subjected for respirometry, PlGF-treated differentiated adipocytes showed higher oxygen consumption rates than controls. PlGF induced AMPK phosphorylation and blockade of AMPK phosphorylation blunted UCP1 and OXPHOS expression in differentiated adipocytes. PlGF administration reduced cholesterol and triglyceride content in the liver and improved insulin sensitivity in db mice compared with control. In Conclusion, PlGF could activate BAT function. Downregulation of PlGF might contribute to the reduced BAT activity in GDM.


Assuntos
Tecido Adiposo Marrom/metabolismo , Diabetes Gestacional/metabolismo , Fator de Crescimento Placentário/metabolismo , Adipócitos Marrons/metabolismo , Adulto , Estudos de Casos e Controles , Diferenciação Celular , Ensaio de Imunoadsorção Enzimática , Feminino , Glucose/metabolismo , Humanos , Raios Infravermelhos , Mitocôndrias/metabolismo , Fosforilação , Gravidez , Termografia , Trofoblastos/metabolismo
9.
Molecules ; 23(8)2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30071619

RESUMO

The mechanism and kinetics for the reaction of the HO2 radical with the ethyl (C2H5) radical have been investigated theoretically. The electronic structure information of the potential energy surface (PES) is obtained at the MP2/6-311++G(d,p) level of theory, and the single-point energies are refined by the CCSD(T)/6-311+G(3df,2p) level of theory. The kinetics of the reaction with multiple channels have been studied by applying variational transition-state theory (VTST) and Rice⁻Ramsperger⁻Kassel⁻Marcus (RRKM) theory over wide temperature and pressure ranges (T = 220⁻3000 K; P = 1 × 10-4⁻100 bar). The calculated results show that the HO2 radical can attack C2H5 via a barrierless addition mechanism to form the energy-rich intermediate IM1 C2H5OOH (68.7 kcal/mol) on the singlet PES. The collisional stabilization intermediate IM1 is the predominant product of the reaction at high pressures and low temperatures, while the bimolecular product P1 C2H5O + OH becomes the primary product at lower pressures or higher temperatures. At the experimentally measured temperature 293 K and in the whole pressure range, the reaction yields P1 as major product, which is in good agreement with experiment results, and the branching ratios are predicted to change from 0.96 at 1 × 10-4 bar to 0.66 at 100 bar. Moreover, the direct H-abstraction product P16 C2H6 + ³O2 on the triplet PES is the secondary feasible product with a yield of 0.04 at the collisional limit of 293 K. The present results will be useful to gain deeper insight into the understanding of the kinetics of the C2H5 + HO2 reaction under atmospheric and practical combustion conditions.


Assuntos
Radical Hidroxila/química , Modelos Teóricos , Cinética , Teoria Quântica
10.
Molecules ; 22(12)2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29194394

RESUMO

Theoretical investigations are performed on mechanism and kinetics of the reaction of halogen peroxy radical ClOO with NO radical. The electronic structure information for both of the singlet and triplet potential energy surfaces (PESs) is obtained at the MP2/6-311 + G(2df) level of theory, and the single-point energies are refined by the CCSD(T)/6-311 + G(2df) level. The rate constants for various product channels of the reaction in the pressure range of 1-7600 Torr are predicted. The main results are as follows: On the singlet surface, the addition-elimination mechanism is the most important. First, the N atom of the NO radical can attack the O atom of the ClOO radical to form an energy-riched intermediate IM1 ClOONOtp (21.3 kcal/mol) barrierlessly, then IM1 could isomerizes to IM2 ClOONOcp (22.1 kcal/mol) via a low energy barrier. Both IM1 and IM2 can dissociate to the primary product P1 ClNO + ¹O2 and the secondary product P2 ClO + NO2. On the triplet surface, the direct Cl-abstraction reaction is the most feasible pathway. The Cl-abstraction can take place via a van der Waals complex, ³IM1 ONClOO (4.1 kcal/mol), then it fragments readily to give P1' ClNO + ³O2 with a small barrier. The kinetic calculations show that at low temperatures, the singlet bimolecular product P1 is the primary product, while at high temperatures, the triplet product P1' becomes the primary one; only at high pressures and low temperatures, the unimolecular products IM1 and IM2 can be found with quite small yields. At experimentally measured temperature 213 K, ClNO is the primary product in the whole pressure range, which is consistent with the previous experiment. The present study may be useful for further experimental studies for the title reaction.


Assuntos
Compostos Clorados/química , Óxido Nítrico/química , Óxidos/química , Simulação por Computador , Isomerismo , Cinética , Modelos Químicos , Pressão , Temperatura , Termodinâmica
11.
Sci Rep ; 6: 39193, 2016 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-27982067

RESUMO

Both brown adipocytes (BAC) and beige cells hold therapeutic potential for the treatment of metabolic disorders. Unfortunately, the amount and activity of these cells are limited in adults. Although BAC marker expression has been shown in peri-renal adipose tissues in children and adults, functional assessment is lacking. Furthermore, it is entirely unknown whether adipose progenitors are present in human embryo and able to give rise to BAC in situ during evolution. Therefore, adipose tissues in the interscapular and peri-renal regions were dissected from human embryo and subcutaneous white adipose tissues (sWAT) were obtained from an adult. After subjected to differentiation in vitro, adipocyte progenitors were detected present in all these adipose tissues. When stimulated for adipogenesis, differentiated adipocytes in the intercapular and peri-renal regions showed similar features: (1) induced BAC and beige cell marker expression including UCP1 and PRDM16 and comparable mitochondrion copy number; (2) similar gene expression patterns by RNA-Seq analysis; and (3) similar maximal oxygen consumption rates examined by respirometry. Nevertheless, stimulation of adipocyte progenitors in sWAT induces neither BAC and beige cell marker expression nor any change of oxygen consumption. In conclusion, peri-renal adipocyte progenitors in human embryo hold browning potential for BAC production.


Assuntos
Adipócitos Marrons/metabolismo , Embrião de Mamíferos/citologia , Adipócitos Marrons/citologia , Adipócitos Brancos/citologia , Adipócitos Brancos/metabolismo , Adipogenia , Células Cultivadas , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mitocôndrias/metabolismo , RNA/química , RNA/isolamento & purificação , RNA/metabolismo , Análise de Sequência de RNA , Células-Tronco/citologia , Células-Tronco/metabolismo , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcriptoma , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/genética , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo
12.
Biomed Environ Sci ; 29(7): 524-8, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27554123

RESUMO

Bovine aortic endothelial cells (BAECs) were cultured with high glucose (33 mmol/L), 4 mg/L green tea polyphenols (GTPs) or 4 mg/L GTPs co-treatment with high glucose for 24 h in the presence or absence of Bafilomycin-A1 (BAF). We observed that high glucose increased the accumulation of LC3-II. Treatment with BAF did not further increase the accumulation of LC3-II. Results also showed an increased level of p62 and decreased Beclin-1. However, GTPs showed inversed trends of those proteins. Furthermore, GTPs co-treatment with high glucose decreased the level of LC3-II and a much higher accumulation of LC3-II was observed in the presence of BAF in comparison with high glucose alone. Results also showed a decreased p62 and increased Beclin-1. The results demonstrated that GTPs alleviated autophagy inhibition induced by high glucose, which may be involved in the endothelial protective effects of green tea against hyperglycemia.


Assuntos
Autofagia/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Glucose/toxicidade , Polifenóis/farmacologia , Chá/química , Animais , Bovinos , Células Cultivadas , Células Endoteliais/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Macrolídeos/farmacologia , Polifenóis/química
13.
Guang Pu Xue Yu Guang Pu Fen Xi ; 33(9): 2425-8, 2013 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-24369645

RESUMO

In the present paper, DMSO/H2O mixture with the ratio of volume 1:1 was measured in the cooling process by Raman spectroscopy, and the Raman assignments was made to the DMSO molecular and water molecular. The results showed that the behavior between intra-molecular hydrogen bonds and inter-molecular hydrogen bonds of DMSO and water leads to the change in the Raman spectra of the S==O stretching vibration of DMSO and the O--H stretching vibration of water. Further analysis showed that the hydrogen bond between DMSO and water was enhanced in the course of temperature decreasing process (27 to -30 degrees C), and the intramolecular hydrogen bonds between water and water replaced the intermolecular hydrogen bonds of DMSO and water in the course of temperature decreasing process (-30 to -60 degrees C). The research provides experimental basis for hydrogen bonding theory in aqueous solution.

14.
Guang Pu Xue Yu Guang Pu Fen Xi ; 33(9): 2429-32, 2013 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-24369646

RESUMO

In the present paper, studies on in-situ Raman spectra at high pressure up to 12.85 Gpa were performed on beta-carotene using a diamond anvil cell (DAC), and the effects of pressure on the characteristic peaks and pi-electron delocalization of beta-carotene were discussed. The results showed that Raman frequencies of the main characteristic peaks of beta-carotene shifted to high wavenumber with the increase in pressure. The relation between pressure and the three main characteristic peaks of beta-carotene was given as follows: nu1, (C==C) = 4. 74P + 1511.4, w (C-C) = 2.55P + 157.6 and nu3 (CH3) = 2.25P + 1011.3. Under the pressure of 5.38 GPa, Raman spectrum of nu1 + nu2 sum frequency of beta-carotene was subjected to cleavage. Fuethermore, the degree of relectron decolization was reduced with the increase in pressure, leading to C==C double bond more compressible than C-C bond on the main chain of beta-carotene.


Assuntos
Análise Espectral Raman , beta Caroteno/química , Elétrons , Estrutura Molecular , Pressão
15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(11): 3031-4, 2012 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-23387173

RESUMO

In the present paper, the frequency shift and line widths of acetonitrile/H2O, DMSO/H2O and acetone/H2O aqueous binary solutions at different concentration were measured by Raman spectroscopy. The experimental results were analyzed by mixture model and empirical formula of line widths. The results show that the stronger the hydrogen bond interaction, the greater the line widths of Raman spectra in the three aqueous binary solutions; the line width of Raman spectra not only is affected by concentration fluctuation, but also is affected by hydrogen bond. In addition, the experimental data points are again nicely fitted using the empirical formula.

16.
J Comput Chem ; 32(7): 1449-55, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21264880

RESUMO

The mechanism for the reaction of the cyanogen radical (CN) with the cyanomidyl radical (HNCN) has been investigated theoretically. The electronic structure information of the singlet and triplet potential energy surfaces (PESs) is obtained at the B3LYP/6-311+G(3df,2p) level, and the single-point energies are refined at the CCSD(T)/6-311+G(3df,2p) level as well as by multilevel MCG3-MPWB method. The calculations show that the C atom of CN additions to middle- and end-N atoms of HNCN are two barrierless association processes leading to the energy-rich intermediates IM1 HN(CN)CN and IM2 HNCNCN, respectively, on the singlet PES. The higher barriers of the subsequent isomerization and dissociation channels from IM1 and IM2 indicate that these two intermediates, which have considerably thermodynamic and kinetic stability, are the dominant product at high pressure. While at low pressure, the most favorable product is P(2) H + NCNCN, which will be formed from both IM1 and IM2 via direct dissociation processes by the H-N bond rupture, and the secondary feasible product is P(4) HCN + (1) NCN, while P(5) HCCN + N(2) and P(6) HCNC + N(2) are the least competitive products. On the triplet PES, P(14) NCNC + HN may be a comparable competitive product at high temperature. In addition, the comparison between the mechanisms of the CN + HNCN and OH + HNCN reactions is made. The present results will enrich our understanding of the chemistry of the HNCN radical in combustion processes and interstellar space.


Assuntos
Cianamida/química , Nitrilas/química , Teoria Quântica , Radicais Livres/química
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