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To isolate and identify secondary metabolites of marine-derived Streptomyces sp.MDW-06,the isolations and purifications of compounds were performed by means of column chromatography over silica gel. And their structures were elucidated through the spectroscopic analysis of MS,NMR and specific rotations. The bioactivities were assayed by paper diffusion and DPPH method. From the fermentation broth of marine-derived Streptomyces sp.MDW-06,five compounds( 1-5) were isolated and identified as streptopentanoic acid( 1),germicidin A( 2),germicidin B( 3),isogermicidin A( 4),isogermicidin B( 5) and oxohygrolidin( 6),respectively. Compound 1 is a new compound. Compound 1 shows DPPH radical scavenging activity with 36. 4% at 100 mg·L~(-1).
Sujet(s)
Chromatographie , Fermentation , Piégeurs de radicaux libres , Chimie , Spectroscopie par résonance magnétique , Polycétides , Chimie , Streptomyces , ChimieRÉSUMÉ
Iron-doped titanium dioxide nanosheets was prepared by hydrothermal method using tetrabutyl titanate (C16H36O4Ti) and iron trifluoride (FeF3) and modified on ITO electrode.ITO/Fe : TiO2/CdS photoelectrochemical sensor was fabricated by successive ionic layer absorption and reaction(SILAR) method for determination of copper ion.The band gap of electode material was narrowed by iron doped TiO2 nanosheets,which made its absorption red-shifted and its response range of light was magnified.Based on the sensitization effect of CdS,the absorption and utilization of visible light of sensor was significantly enhanced and the photoelectric signal was amplified via reducing the recombination of electrons and holes.The sensor displayed excellent analytical performance for detection of copper ion with linear range of 0.2-4.0 μmol/L and 4.0-80.0 μmol/L and with the detection limit of 85 nmol/L.The sensor was used to detect copper ion in tap water,drinking water and Yongjiang river water with recoveries ranging from 94% to 111%.
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OBJECTIVE@#To explore the relationship between caregivers' nutritional knowledge and children's dietary behavior in rural areas of China.@*METHODS@#A cross-sectional study was conducted. 3361 rural caregivers and their children, aged 2 to 7 years old, were selected randomly and surveyed by questionnaire. Logistic regression models were used to identify the relationship between caregivers' nutritional knowledge and the children's dietary behaviors.@*RESULTS@#The awareness level of nutritional knowledge among rural caregivers was 57.9%; among the children surveyed, 79.6% did not like to drink milk, 66.0% were considered choosy of food, 84.1% regularly snacked, 24.4% frequently skipped breakfast, and 13.7% did not come to meals on time. Logistic regression models indicated that a caregiver with a low level of nutritional knowledge is a risk factor for a child's unhealth dietary behaviors (snacking excepted): the odds ratios (OR) of not liking to drink milk, being choosy about food, skipping breakfast or not having meals on time are 1.665, 1.338, 1.330 and 1.582, respectively.@*CONCLUSION@#Caregivers' nutritional knowledge is strongly associated with children's dietary behavior. Nutrition education programs are urgently wanted to improve caregiver's knowledge and thus to improve children's dietary behavior in rural areas of China.
Sujet(s)
Enfant , Enfant d'âge préscolaire , Femelle , Humains , Mâle , Aidants , Éducation , Comportement de l'enfant , Psychologie , Phénomènes physiologiques nutritionnels chez l'enfant , Chine , Comportement alimentaire , Psychologie , Préférences alimentaires , Psychologie , Connaissances, attitudes et pratiques en santé , Modèles logistiques , Population rurale , Enquêtes et questionnairesRÉSUMÉ
Objective To explore knowledge, attitude, practice (KAP) and related determinants on nutrition among caregivers of those rural stranded children under 7 years of age in China and to provide evidence for setting up relevant health education program. Methods 1691 caregivers of the stranded children randomly selected were surveyed by a standard questionnaire. Logistic regression models were used to screen the determinants on KAP regarding nutrition. Results Rates on awareness, positive attitude and approprite behavior were lower in caregivers of children whose parents both left (47.8%, 55.4%, 41.8%, respectively) the countryside, when compared with those only one parent was away from home (59.9%, 59.5%, 38.0%, respectively). Data from multivariable logistic regression models showed that caregivers' KAP on nutrition was related to age, educational background, average family income, and willingness on the job as well as the age of the child. Conclusion Improving caregivers' KAP on nutrition and setting up appropriate health education program were in urgent need.
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Objective:To test a model in which self-esteem mediated the effects of behavior on exposure to violence(victimization) in a sample of rural middle school students.Methods:A cross-section study was conducted in 3620 middle school students randomly selected from rural areas.A questionnaire of violence(WHO) and Achenbach Children Behavior Checklist(CBCL) and Rosenberg self-esteem scale were used to measure the exposure to violence behavior,and self-esteem respectively.Results:Hierarchical regression analyses provided evidence that the addition of self-esteem reduced the links between behavior and exposure to violence(? from 0.232 to 0.226).Sobel Z-test predicted that self-esteem partially mediated the effects of behavior on exposure to violence(victimization) with significant difference(? from 0.232 to 0.226,Sobel-Z value=2.340,P=0.019).Speech violence,physical violence,and sexual violence were tested by the same model respectively,and the results showed that self-esteem partially mediated the effects of behavior on speech violence with significant difference(? from 0.225 to 0.200,Sobel-Z value=1.992,P=0.046),but not on physical or sexual violence.Conclusion:Self-esteem partially mediates the effects of behavior on exposure to violence(emotion violence).