ABSTRACT
In this study, the process of manufacturing nanohydrogels containing papain and how to release it was investigated. Chitosan nanohydrogels and chitosan-polyethylene glycol hybrid nanohydrogels were used to entrapment of papain as a protein model. In order to evaluate and confirm different properties of nanohydrogels such as size, shape, the rate of swelling and flexibility, different methods was used. The maximum amount of papain entrapment was observed in 0.75% concentration of chitosan and 1% concentration of sodium Tripolyphosphate (TPP) as linker. The results of scanning electron microscope (SEM) and X-ray diffraction (XRD) patterns showed that nanohydrogels containing papain on a nano scale are very porous and swollen. Differential scanning calorimetry (DSC) thermograms analysis showed that nanohydrogels have relatively good water absorption capacity. Also, by adding polyethylene glycol to chitosan, the melting temperature of hybrid nanohydrogels decreased and this can be a reason for the formation of flexible structures in these nanohydrogels. In chitosan nanohydrogels, the highest release rate of papain was observed at pH lower than 7 and high temperatures, but by adding polyethylene glycol to the chitosan, in addition to increasing papain release, a proper and continuous release of papain was observed at temperature and pH close to physiological conditions, especially at low ratios of polyethylene glycol. According to the present results, hybrid nanohydrogels can have a good potential in protein delivery systems in terms of structure and release.
ABSTRACT
Formaldehyde is a volatile organic compound (VOC) with extensive applications, volatility, and toxicity, which have made it an important risk to human health even at low concentrations. Therefore, rapid detection of formaldehyde vapors in the environment is a necessity. Herein, we introduce a resistive gas sensor based on zeolitic imidazolate framework-8/multiwalled carbon nanotube (ZIF-8/MWCNT) for detection of formaldehyde vapors at room temperature. In this sensor, a low amount of MWCNTs was used in order to improve the electrical conductivity of the porous nanoparticles of ZIF-8. The sensor was fabricated by deposition of a thin layer of the nanocomposite onto interdigitated electrodes, and its sensing ability was investigated on exposure to formaldehyde vapors. The obtained sensor showed sensitive and fast responses to different concentrations of formaldehyde, and the sensor response to formaldehyde was higher than toward some other VOCs, including methanol, ethanol, acetone, and acetonitrile. Furthermore, because of the hydrophobic nature of ZIF-8, the effect of relative humidity on the gas-sensing performance was insignificant, which proves that this sensor is suitable for use under humid conditions.
ABSTRACT
AIM: This study aimed to investigate the association of children's obesity with parental attachment and psychological variables as impulsivity, self-control and efficiency of eating control. METHODS: This cross-sectional study was conducted among 202 obese students aged 9-13 years selected by multistage cluster sampling from different areas of Isfahan, Iran. Three questionnaires were considered to be answered by the students and one for their parents. The students completed the following questionnaires: (i) Inventory of Parent and Peer Attachment-Revised version for Children (IPPA-R); (ii) Impulsivity Scale (IS); (iii) Efficiency of Eating Control; and (iv) Self-control Rating Scale (SCRS). RESULTS: The quality of children's attachment had direct effects on self-efficacy of eating management and on obesity by mediating of self-efficacy of eating. Moreover, attachment had direct effect on self-control and impulsivity, and in turn through these psychological variables, it had indirect effects on self-efficacy of eating management. CONCLUSION: The findings of this study underscore the importance of parent-child attachment quality. It can be suggested that childhood obesity can be prevented and managed with creating a secure attachment bond between children and parents and increasing perceived self-efficacy eating management in children.
Subject(s)
Obesity/psychology , Parent-Child Relations , Adolescent , Child , Cross-Sectional Studies , Female , Humans , Impulsive Behavior , Male , Self EfficacyABSTRACT
BACKGROUND: Assessing growth is a useful tool for defining health and nutritional status of children. The objective of this study was to construct growth reference curves of Iranian infants and children (0-6 years old) and compare them with previous and international references. METHODS: Weight, height or length of 2107 Iranian infants and children aged 0-6 years old were measured using a cross-sectional survey in Tehran in 2010. Standard smooth reference curves for Iranian population were constructed and compared to multinational World Health Organization 2006 reference standards as well as a previous study from two decades ago. RESULTS: Growth index references for Iranian girls are increased in compare to data from two decades ago and are approximately close to the international references. In boys; however, the increment was considerably large as it passed the international references. Not only the values for indexes was changed during two decades, but also the age at adiposity rebound came near the age of 3, which is an important risk factor for later obesity. CONCLUSIONS: During two decades, growth indexes of Iranian children raised noticeable. Risk factors for later obesity are now apparent and demand immediate policy formulations. In addition, reference curves presented in this paper can be used as a diagnostic tool for monitoring growth of Iranian children.
ABSTRACT
BACKGROUND: Recurrent Herpes Labialis (RHL) is one of most common infective vesiculoulcerative lesions. According to some studies administration of topical and/or systemic zinc compositions has been effective in treatment and prevention. This article aims to comparison of zinc level in healthy subjects and RHL patients in acute and convalescent phases. MATERIALS AND METHODS: This was a retrospective case - control study, carried on 80 individuals (40 normal and 40 RHL patients) mean age=34.5 and 34.4, respectively. Saliva samples were taken in patients in acute phase once and after healing of lesions in convalescent phase (averagely 21 days later) and in normal individuals. Salivary zinc level concentration was measured by flame atomic absorption spectrophotometer by dry digestion method. The results were statistically analyzed with SPSS software by t-test (α=0.05). RESULTS: Results showed that salivary zinc level in case group in acute and convalescent phases were 160.8 (ngr)/(ml)and 205.7 (ngr)/(ml) respectivly and significant differences between them were existed (P <0.05). Also significant differences were existed between zinc concentration in healthy subjects and patient groups (in both phases) (P=.001 and .002 for acute and convalescent phases respectively). CONCLUSION: According to the results, zinc level is significantly lower in acute phase than in convalescent phase and significantly lower in both phases compared to healthy individuals,so determination of serum zinc level and prescribing zinc complement in low serum status has both treatmental and preventive effects in RHL patients.
