Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Eur J Pediatr ; 182(7): 2943-2956, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37071174

RESUMEN

Dietary therapies are recommended for the treatment of pediatrics with functional abdominal pain disorders (FAPDs), but the comparative effectiveness among them is unclear. Therefore, the main aim of this systematic review and meta-analysis was to compare the effectiveness of differential dietary therapies in pediatrics with functional abdominal pain disorders. We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases from inception to February 28, 2023. Randomized clinical trials of dietary treatments for pediatric patients with functional abdominal pain disorders were included. The primary outcome was the improvement in abdominal pain. The secondary outcomes were changes in pain intensity and pain frequency. Thirty-one studies after screening 8695 retrieved articles were included, and 29 studies were available for network meta-analysis. Compared with placebo, fiber (RR, 4.86; 95%CI, 1.77 to 13.32; P-score = 0.84), synbiotics (RR, 3.92; 95%CI, 1.65 to 9.28; P-score = 0.75), and probiotics (RR, 2.18; 95%CI, 1.46 to 3.26; P-score = 0.46) had significantly larger effect on the improvement in abdominal pain, the three treatments had larger effect than placebo but statistically insignificant in difference in improving pain frequency and intensity. Similarly, there were no significant differences between the dietary treatments after indirect comparisons of the three outcomes.  Conclusion: Fiber supplements, synbiotics, and probiotics were efficacious in improving abdominal pain of FAPDs in children, suggested by very low or low evidence. The evidence of the efficacy of probiotics is more convincing than fiber and synbiotics when sample size and statistical power were considered. No difference in the efficacy of the three treatments. High-quality trials are needed to further investigate the efficacy of dietary interventions. What is Known: • Multiple dietary treatment options are available for functional abdominal pain disorders in the pediatric population, of which the most beneficial one is currently unknown. What is New: • This NMA found very low to low certainty of the evidence suggesting that fiber, synbiotics, and probiotics might be more efficacious in improving abdominal pain of FAPDs in children than the other dietary treatments. • There were no significant differences between active dietary treatments for changes in abdominal pain intensity.


Asunto(s)
Probióticos , Simbióticos , Humanos , Niño , Metaanálisis en Red , Probióticos/uso terapéutico , Dolor Abdominal/terapia
2.
Chem Pharm Bull (Tokyo) ; 67(7): 690-692, 2019 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-31006721

RESUMEN

Photodynamic therapy (PDT) is a modern cancer therapy. But it is still difficult to obtain ideal photosensitizers. We synthesized six new peri-xanthenoxanthene derivatives rapidly and efficiently using solid-phase carbon-bath microwave irradiation technology, and investigated their in vitro photodynamic antitumor activity with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Our results showed that all compounds exhibited extremely low dark cytotoxicity and good phototoxicity against four human cancer cell lines. In particular, compound 3c showed the best in vitro PDT activity against Hela cells and Bel-7402 cells with IC50 values of 91 and 74 nmol/L, respectively. Its value of 1-octanol/water partition coefficient (log Kow) was 0.5309, suggesting that it is a promising photosensitizer for PDT due to its low dark cytotoxicity, high phototoxicity, and potential water solubility.


Asunto(s)
Fármacos Fotosensibilizantes/síntesis química , Xantenos/química , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Células HeLa , Humanos , Concentración 50 Inhibidora , Microondas , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Fotoquimioterapia , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/uso terapéutico , Especies Reactivas de Oxígeno/metabolismo , Xantenos/farmacología , Xantenos/uso terapéutico
3.
Biomed Environ Sci ; 31(5): 382-388, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29866220

RESUMEN

We sought to identify the differences between adolescents left behind in their home villages/towns (LBA) and non-left behind adolescents (NLB) on subjective well-being and family functioning due to parental migration in south China. We used a stratified cluster sampling method to recruit middle school students in a city experiencing population-emigration in Jiangxi Province in 2010. Participants included adolescents from families with: (1) one migrant parent, (2) both parents who migrated, or (3) non-left behind adolescents (i.e., no migrant parent). To determine predictors of subjective well-being, we used structural equation models. Adolescents left behind by both parents (LBB) were less likely to express life satisfaction (P = 0.038) in terms of their environments (P = 0.011) compared with NLB. A parent or parents who migrated predicts lower subjective well-being of adolescents (P = 0.051) and also lower academic performance. Being apart from their parents may affect family functioning negatively from an adolescent's viewpoint. Given the hundreds of millions of persons in China, many who are parents, migrating for work, there may be mental health challenges in some of the adolescents left behind.


Asunto(s)
Emigración e Inmigración , Población Rural , Migrantes , Adolescente , Envejecimiento , China , Femenino , Humanos , Masculino , Salud Mental/estadística & datos numéricos , Relaciones Padres-Hijo , Padres , Psicología del Adolescente , Factores Socioeconómicos , Encuestas y Cuestionarios
4.
Zhong Yao Cai ; 38(1): 160-2, 2015 Jan.
Artículo en Zh | MEDLINE | ID: mdl-26214885

RESUMEN

OBJECTIVE: To study the glycosides from Guangdong Liangcha Granules. METHODS: The chemical constituents were isolated by various chromatographic techniques and the structures of chemical constituents were identified by spectroscopic analysis and literature. RESULTS: Six compounds were isolated and identified as ilexoside B (1), asprellanosides B (2), asprellanoside A (3), 4', 5 ,7 -tri- hydroxyflavone-6-O-ß3-D-glucopyranosyl ester(4), isoviolanthin (5),3-O-methy-lellagic acid 4'-O-rhamnopyranoside (6). CONCLUSION: Compounds 1 - 5 are firstly obtained from Guangdong Liangcha Granules.


Asunto(s)
Medicamentos Herbarios Chinos/química , Glicósidos/análisis , Saponinas , Triterpenos
5.
Acta Neurol Belg ; 123(4): 1481-1493, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37184609

RESUMEN

BACKGROUND AND OBJECTIVES: Migraine is a major public health problem owing to its long disease duration and disease relapse. Non-invasive brain stimulation treatments were reported effective for the management of migraine, but the comparative effectiveness of three main NIBSs, rTMS, nVNS, and tDCS, has not been studied. We aimed to explore the relative efficacy of rTMS, tDCS, and nVNS in migraine prophylaxis by using network meta-analysis (NMA). METHODS: We searched OVID Medline, Embase, Cochrane Controlled Register of Trials, and Web of Science from inception to 1 January 2022. Randomized controlled trials that reported the efficacy of rTMS, tDCS or nVNS in the prophylactic treatment of migraine were included. The primary outcome was monthly migraine frequency, and secondary outcomes were headache intensity and the impact of headaches on daily life. The relative effects of the treatments in contrast to the others were measured by using standard mean difference (SMD). RESULTS: We included 31 trials with 1659 participants. Fourteen trials were rated as low risk of bias. The results showed that tDCS (SMD - 1.58; 95%CI, - 2.38 to - 0.79; P-score = 0.92) had the largest effect on migraine frequency when compared with sham interventions in reducing monthly migraine frequency, and tDCS had a larger effect than rTMS (SMD - 0.62; 95%CI, - 1.81 to 0.57) and nVNS (SMD - 1.39; 95%CI, - 3.27 to 0.49). tDCS had also the largest effect in reducing pain intensity when compared with sham intervention (SMD - 1.49; 95%CI, - 2.46 to - 0.52) and rTMS (SMD - 0.48; 95%CI, - 2.06 to 1.09). CONCLUSIONS: For the prophylactic treatment of migraine, tDCS was relatively more effective than rTMS and nVNS. Head-to-head comparison trials are needed to confirm the findings.


Asunto(s)
Trastornos Migrañosos , Humanos , Metaanálisis en Red , Ensayos Clínicos Controlados Aleatorios como Asunto , Trastornos Migrañosos/prevención & control , Estimulación Magnética Transcraneal , Cefalea , Encéfalo/fisiología
6.
Adv Rheumatol ; 63(1): 42, 2023 08 18.
Artículo en Inglés | MEDLINE | ID: mdl-37596678

RESUMEN

BACKGROUND: The etiology of systemic lupus erythematosus is complex and incurable. A large number of systematic reviews have studied the risk factors of it. Mendelian randomization is an analytical method that uses genetic data as tool variables to evaluate the causal relationship between exposure and outcome. OBJECTIVE: To review the systematic reviews and Mendelian randomization studies that focused on the risk factors of systemic lupus erythematosus and shed light on the development of treatments for its prevention and intervention. METHODS: From inception to January 2022, we systematically searched MEDLINE (via PubMed) and Embase for related systematic reviews and Mendelian randomization studies. Extract relevant main data for studies that meet inclusion criteria. The quality of systematic reviews was assessed by using Assessment of Multiple Systematic Reviews 2 (AMSTAR-2). Finally, the risk factors are scored comprehensively according to the results' quantity, quality, and consistency. RESULTS: Our study involved 64 systematic reviews and 12 Mendelian randomization studies. The results of systematic reviews showed that diseases (endometriosis, atopic dermatitis, allergic rhinitis), lifestyle (smoking, drinking, vaccination), and gene polymorphism influenced the incidence of systemic lupus erythematosus. The results of Mendelian randomization studies identified the role of disease (periodontitis, celiac disease), trace elements (selenium, iron), cytokines (growth differentiation factor 15), and gut microbiome in the pathogenesis of systemic lupus erythematosus. CONCLUSION: We should pay attention to preventing and treating systemic lupus erythematosus in patients with endometriosis, celiac disease, and periodontitis. Take appropriate dietary supplements to increase serum iron and selenium levels to reduce the risk of systemic lupus erythematosus. There should be no excessive intervention in lifestyles such as smoking and drinking.


Asunto(s)
Enfermedad Celíaca , Endometriosis , Lupus Eritematoso Sistémico , Selenio , Femenino , Humanos , Análisis de la Aleatorización Mendeliana , Revisiones Sistemáticas como Asunto , Factores de Riesgo , Hierro , Lupus Eritematoso Sistémico/genética
7.
Appl Bionics Biomech ; 2022: 2586400, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35498145

RESUMEN

Background: This study is aimed at to establish an effective prognostic nomogram for patients with atrial fibrillation (AF) and acute coronary syndrome (ACS) underwent percutaneous coronary intervention (PCI). Methods: The nomogram was based on a retrospective study of 977 patients with AF and ACS who underwent PCI who were admitted to any of the 11 tertiary hospitals in the Beijing area between 2009 and 2015. The predictive accuracy and discriminative ability of the nomogram were determined by a concordance index (C-index) and calibration curve and were compared using current risk scores such as GRACE, CRUSADE, CHA2DS2-VASc, and HAS-BLED. The results were validated using bootstrap resampling and a retrospective cohort study of 409 patients enrolled in Fuwai Hospital at the same institution. Results: Independent factors derived from multivariable analysis of the primary cohort to predict all-cause mortality were age, pattern of ACS, red blood cell distribution width, N-terminal proBNP, and serum creatinine, all of which were assembled into the nomogram. The calibration curve for the probability of recurrence showed that the nomogram-based predictions were in good agreement with actual observations. The C-index of the nomogram for predicting mortality was 0.764 (95% CI, 0.718-0.810), which was statistically higher than the C-index values for the current risk scores (from 0.573 to 0.681). In the validation cohort, the C-index of the nomogram for predicting all-cause death was 0.706 (95% CI 0.601-0.811), with no significant differences compared with GRACE and CRUSADE, but better than that of CHA2DS2-VASc and HAS-BLED. Conclusions: The nomogram has good prognostic prediction for patients with AF and ACS who underwent PCI.

8.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 6): o1516, 2011 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-21754881

RESUMEN

In the title compound, C(23)H(23)NO(4), the dihedral angle beween the chromen-2-one ring system and the benzene ring is 69.73 (10)° and the mol-ecule adopts an E conformation with respect to the C=N double bond. In the crystal, inversion dimers linked by pairs of C-H⋯O hydrogen bonds occur, generating R(2) (2)(12) loops.

9.
Br J Nutr ; 103(4): 608-16, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19878616

RESUMEN

Dietary protein restriction is one major therapy in chronic kidney disease (CKD), and ketoacids have been evaluated in CKD patients during restricted-protein diets. The objective of the present study was to compare the efficacy of a low-protein diet supplemented with ketoacids (LPD+KA) and a low-protein diet alone (LPD) in halting the development of renal lesions in CKD. 5/6 Nephrectomy Sprague-Dawley rats were randomly divided into three groups, and fed with either 22 % protein (normal-protein diet; NPD), 6 % protein (LPD) or 5 % protein plus 1 % ketoacids (LPD+KA) for 24 weeks. Sham-operated rats were used as controls. Each 5/6 nephrectomy group included fifteen rats and the control group included twelve rats. Proteinuria, decreased renal function, glomerular sclerosis and tubulointerstitial fibrosis were found in the remnant kidneys of the NPD group. Protein restriction ameliorated these changes, and the effect was more obvious in the LPD+KA group after 5/6 nephrectomy. Lower body weight and serum albumin levels were found in the LPD group, indicating protein malnutrition. Lipid and protein oxidative products were significantly increased in the LPD group compared with the LPD+KA group. These findings indicate that a LPD supplemented with ketoacids is more effective than a LPD alone in protecting the function of remnant kidneys from progressive injury, which may be mediated by ketoacids ameliorating protein malnutrition and oxidative stress injury in remnant kidney tissue.


Asunto(s)
Antioxidantes/uso terapéutico , Dieta con Restricción de Proteínas , Cetoácidos/uso terapéutico , Riñón/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Insuficiencia Renal Crónica/dietoterapia , Animales , Antioxidantes/farmacología , Peso Corporal/efectos de los fármacos , Proteínas en la Dieta/metabolismo , Suplementos Dietéticos , Fibrosis/prevención & control , Cetoácidos/farmacología , Riñón/patología , Riñón/fisiopatología , Metabolismo de los Lípidos/efectos de los fármacos , Masculino , Nefrectomía , Deficiencia de Proteína/dietoterapia , Proteinuria/prevención & control , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Insuficiencia Renal Crónica/patología , Esclerosis/prevención & control , Albúmina Sérica/metabolismo
10.
Chem Pharm Bull (Tokyo) ; 57(11): 1273-7, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19881280

RESUMEN

A series of hydroxy- or methoxy-substituted phenylmethylenethiosemicarbazones were designed, synthesized and evaluated as mushroom tyrosinase inhibitors. The results demonstrated that most of target compounds had remarkable inhibitory activities on mushroom tyrosinase. Interestingly, compound 2h was found to be the most potent tyrosinase inhibitor with IC50 value of 0.18 microM. The possible interaction mode between compound 2h and tyrosinase was proposed. In addition, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities of select compounds (IC50<10.0 microM) were also investigated. Compounds 2d, 2e, 2h, 2i and 2l exhibited more potent DPPH radical scavenging activity than well-known antioxidants ascorbic acid (Vc) and tertiary butyl hydroquinone (TBHQ). These results suggested that such compounds might be utilized for the development of new candidate for treatment of dermatological disorders.


Asunto(s)
Diseño de Fármacos , Depuradores de Radicales Libres/síntesis química , Monofenol Monooxigenasa/antagonistas & inhibidores , Péptidos/síntesis química , Péptidos/farmacología , Tiosemicarbazonas/síntesis química , Agaricales/enzimología , Depuradores de Radicales Libres/química , Depuradores de Radicales Libres/farmacología , Concentración 50 Inhibidora , Estructura Molecular , Monofenol Monooxigenasa/metabolismo , Péptidos/química , Estereoisomerismo , Relación Estructura-Actividad , Tiosemicarbazonas/química , Tiosemicarbazonas/farmacología
11.
Adv Rheumatol ; 63: 42, 2023. tab, graf
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1513562

RESUMEN

Abstract Background The etiology of systemic lupus erythematosus is complex and incurable. A large number of systematic reviews have studied the risk factors of it. Mendelian randomization is an analytical method that uses genetic data as tool variables to evaluate the causal relationship between exposure and outcome. Objective To review the systematic reviews and Mendelian randomization studies that focused on the risk factors of systemic lupus erythematosus and shed light on the development of treatments for its prevention and intervention. Methods From inception to January 2022, we systematically searched MEDLINE (via PubMed) and Embase for related systematic reviews and Mendelian randomization studies. Extract relevant main data for studies that meet inclusion criteria. The quality of systematic reviews was assessed by using Assessment of Multiple Systematic Reviews 2 (AMSTAR-2). Finally, the risk factors are scored comprehensively according to the results' quantity, quality, and consistency. Results Our study involved 64 systematic reviews and 12 Mendelian randomization studies. The results of systematic reviews showed that diseases (endometriosis, atopic dermatitis, allergic rhinitis), lifestyle (smoking, drinking, vaccination), and gene polymorphism influenced the incidence of systemic lupus erythematosus. The results of Mendelian randomization studies identified the role of disease (periodontitis, celiac disease), trace elements (selenium, iron), cytokines (growth differentiation factor 15), and gut microbiome in the pathogenesis of systemic lupus erythematosus. Conclusion We should pay attention to preventing and treating systemic lupus erythematosus in patients with endometriosis, celiac disease, and periodontitis. Take appropriate dietary supplements to increase serum iron and selenium levels to reduce the risk of systemic lupus erythematosus. There should be no excessive intervention in lifestyles such as smoking and drinking.

12.
Spectrochim Acta A Mol Biomol Spectrosc ; 66(4-5): 1300-6, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16920004

RESUMEN

Thirteen conjugated-chain compounds which contain benzene and furan units were prepared, their optical behaviors, including UV-vis absorption coefficient (epsilon), absorption wavelengths (lambdaa), fluorescence emission wavelengths (lambdae), and quantum yields (Phi) were measured. Meanwhile, their LUMO and HOMO energy were determined by cyclic voltammetry and their second-order polarizations (betaxxx) values were determined by solvatochromic method, respectively. The results showed that this kind of compounds possess a shorter lambdaa (320-365 nm) and performance a higher Phi values, especially for 2aa, 2ab, 2ac and 2bb, their Phi values are all more than 90%. These compounds, except 2db, showed a higher betaxxx values in DMSO, especially for 2dc (75.77x10(-30) m5 C-1) and 2dd (83.32x10(-30) m5 C-1), than that 10-methyl-acridone (6.578x10(-30) m5 C-1) or 10-benzylacridone (6.845x10(-30) m5 C-1) in DMSO did, and second harmonic generation value of 10-methylacridone and 10-benzylacridone in powder are, respectively, 1.381 and 1.861 times of that value of urea. The betaxxx values and Phi values determined for these compounds in this work were lower than these values which were desired in the original work, this phenomena was explained from their molecular structures. This work confirmed that as these compounds performance shorter lambdaa and higher Phi values, they could be good blue-color optical materials for some fields, such as OLED materials, two-photo absorption materials, fluorescent dyes.


Asunto(s)
Benceno/química , Furanos/química , Óptica y Fotónica , Benceno/síntesis química , Furanos/síntesis química , Modelos Químicos , Teoría Cuántica , Solventes , Espectrofotometría Ultravioleta , Electricidad Estática
14.
Curr Top Med Chem ; 16(2): 206-19, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26126908

RESUMEN

Defensins are small cationic cysteine rich peptides, which usually contain 18-45 amino acids and possess amphiphilic properties. The term "defensin" was coined as the sequences of rabbit and human leukin/phagocytin molecules were first reported in 1985. Since then, various defensins were isolated and characterized from insects, plants and vertebrates. Using vertebrate defensins as examples, defensins are categorized into three sub-families based on their different patterns of intramolecular disulfide linkages: α defensins, ß defensins, and θ defensins. During the past decades, continuous attentions were casted on various defensins for their broad activity against bacteria, fungi and viruses. In this review, we focus on the effect of characteristic intramolecular disulfide bonds on the antimicrobial activity of defensins. The disulfide bonds are important for holding the defensins in their three dimensional structures, while also contribute to their antimicrobial activity and chemotactic activity. This review summarizes the effects of disulfide bonds, their synthetic formation pathways and potential pharmaceutical applications.


Asunto(s)
Antiinfecciosos/química , Defensinas/química , Disulfuros/química , Animales , Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Defensinas/farmacología , Hongos/efectos de los fármacos , Humanos , Modelos Moleculares , Virus/efectos de los fármacos
15.
Chem Commun (Camb) ; (23): 2824-5, 2002 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-12478765

RESUMEN

Reaction of propargylic dithioacetal 2a with BuLi gives the sulfur-substituted allenyllithium 3a which is allowed to react with a dialdehyde to yield the corresponding alternating benzene-furan oligoaryls 6. Functional group transformation converts the ester groups in 6 to dialdehyde 8 which can be used for the synthesis of higher homologues towards molecular wires. A combination of this furan annulation, Heck reaction and Sonogashira coupling leads to a variety of benzene-furan-alkene/alkyne conjugated oligomers of precise length.

16.
Spectrochim Acta A Mol Biomol Spectrosc ; 60(7): 1587-91, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15147702

RESUMEN

The maximum absorption wavelengths (lambda(a-max)), absorption coefficient (epsilon), maximum emission wavelengths (lambda(e-max)) of 4-benzo[1,3]dioxol-5-ylmethylene-2-phenyl-4H-oxazol-5-one (1), 4-(3,4-dimethoxybenzylidene)-2-phenyl-4H-oxazol-5-one (2) and 4-(3,4,5-trimethoxy-benzylidene)-2-phenyl-4H-oxazol-5-one (3) were measured, their second-order nonlinear polarization values (beta(xxx)) were determined by solvatochromic method. Although the spectral nature (lambda(a-max), epsilon, lambda(e-max)) and beta(xxx) values of 1, 2 and 3 were close to each other in the same solvent, the second-order harmonic generation (SHG) value of sample 1 is higher obviously than that of sample 2 or 3 in solid state. The crystal structures of 1 and 2 characterized by single crystal X-ray diffraction technique indicated the reason why the SHG value of 1 is higher.


Asunto(s)
Oxazoles/química , Cristalografía por Rayos X , Polarización de Fluorescencia , Modelos Moleculares , Estructura Molecular , Óptica y Fotónica , Espectrofotometría , Espectrofotometría Ultravioleta , Electricidad Estática
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 59(7): 1509-15, 2003 May.
Artículo en Inglés | MEDLINE | ID: mdl-12714074

RESUMEN

The charge-transfer complexes (CTC) between a parent molecule of antipsychotic pharmaceuticals, phenothiazine, and seven unsaturated acid anhydrides, 1,4,5,8-naphtalenetetracarboxylic dianhydride, diphenic anhydride, maleic anhydride (MA), 3,4,5,6-tetrahydrophthalic anhydride (THPA), 3-hydroxy-1,8-naphthalic anhydride (HONA), 4-chloro-1,8-naphthalic anhydride (ClNA), and 1,8-naphthalic anhydride (NA) were studied using IR and UV spectroscopy. Stability constants (K) at different temperatures were measured, and based on the K's DeltaH and DeltaS were calculated. The values of electron affinity (E(A)) of anhydrides were obtained according to Mulliken's theory. The results show that phenothiazine is an excellent donor and has strong ability to complex with the carbonyl group, and the E(A) values have good linear relationships with DeltaH and K, respectively. The solvent effect on CTCs was also determined and explained. The CTC of phenothiazine-succinic anhydride (SA) was studied under the same conditions. It was deduced from the results obtained that there were two charge-accepting centers in the unsaturated acid anhydrides when they formed CTCs with phenothiazine. The first one was carbon atom of the two carbonyl groups and the second one was their -C=C- in the molecules.


Asunto(s)
Antipsicóticos/química , Fenotiazinas/química , Anhídridos/química , Estabilidad de Medicamentos , Humanos , Técnicas In Vitro , Sustancias Macromoleculares , Solventes , Espectrofotometría Infrarroja , Espectrofotometría Ultravioleta , Termodinámica
18.
Artículo en Inglés | MEDLINE | ID: mdl-12788457

RESUMEN

The maximum absorption wavelengths (lambda(a-max)), absorption coefficient (epsilon), maximum emission wavelengths (lambda(e-max)), fluorescent quantum yields (phi(f)), and second-order nonlinear polarizations (beta(xxx)) of seventeen 4,4'-bis-(2-(substituted-styryl))biphenyl and three 1,4-bis-(2-(substituted-styryl))benzene were measured. The results showed that some of this series of compounds possess high fluorescent quantum yields in DMF, such as, 2 (0.801), 3 (0.680), 5 (0.565), 15 (0.538) 16 (0.848), 18 (2.175), 19 (1.314) and 20 (1.060), as compared with quinine-sulfuric acid. They could be used as fluorescent whiteners and fluorescent colorants. Some of these compounds were of a high beta(xxx) values, such as in DMSO, 2 (29.00/10(-30) m(5)c(-1)), 3 (25.29/10(-30) m(5)c(-1)), 8 (21.79/10(-30) m(5)c(-1)) and 9 (24.08/10(-30) m(5)c(-1)). Electron-withdrawing substituent NO(2), which is attached to the two terminal phenyl rings could cause lambda(a-max) obviously to be shorter, but it made lambda(e-max) change longer. Electron-donating substituent at two end benzene rings, such as OCH(3), N((CH(3))(2)), even Cl, could make lambda(a-max) and lambda(e-max) longer, and the larger the electron-donating ability of the substituent, the longer the lambda(a-max) and lambda(e-max). This influence of 4-position substituent on lambda(a-max) or lambda(e-max) is obviously larger than that of 2-position substituent, and the action of substituent on 2-position is larger than that of substituent on 3-position. The values of lambda(a-max) and lambda(e-max) of biphenyl compounds 2 or 3 were respectively close to these values of corresponding benzene compounds 18 or 19.


Asunto(s)
Derivados del Benceno/química , Compuestos de Bifenilo/química , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta
19.
Artículo en Inglés | WPRIM | ID: wpr-690646

RESUMEN

We sought to identify the differences between adolescents left behind in their home villages/towns (LBA) and non-left behind adolescents (NLB) on subjective well-being and family functioning due to parental migration in south China. We used a stratified cluster sampling method to recruit middle school students in a city experiencing population-emigration in Jiangxi Province in 2010. Participants included adolescents from families with: (1) one migrant parent, (2) both parents who migrated, or (3) non-left behind adolescents (i.e., no migrant parent). To determine predictors of subjective well-being, we used structural equation models. Adolescents left behind by both parents (LBB) were less likely to express life satisfaction (P = 0.038) in terms of their environments (P = 0.011) compared with NLB. A parent or parents who migrated predicts lower subjective well-being of adolescents (P = 0.051) and also lower academic performance. Being apart from their parents may affect family functioning negatively from an adolescent's viewpoint. Given the hundreds of millions of persons in China, many who are parents, migrating for work, there may be mental health challenges in some of the adolescents left behind.


Asunto(s)
Adolescente , Femenino , Humanos , Masculino , Envejecimiento , China , Emigración e Inmigración , Salud Mental , Relaciones Padres-Hijo , Padres , Psicología del Adolescente , Población Rural , Factores Socioeconómicos , Encuestas y Cuestionarios , Migrantes
20.
Artículo en Zh | WPRIM | ID: wpr-659921

RESUMEN

Objective To put forward a method for 3D electrical impedance finite element joint modeling and simulation using COMSOL for visual modeling and Visual C++ for programming.Methods A model was established with COMSOL,and then transformed into a.stl file and introduced into Visual C++ simulation platform.Delaunay tetrahedral mesh generation algorithm was used for finite element meshing,calculation and simulation,and joint modeling and simulation were realized finally.Results Simulation result showed that the method could be used to introduce COMSOL model and complete 3D finite element simulation.Conclusion The method proves its compatibility with the models generated by multi software and practicability for joint modeling and simulation.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA