Morfološke i strukturne značajke biofilmova na bazi zeina s dodatkom ksantanske gume

Morphological and structural characteristics of zein-based biofilms have been studied in this work. The sorbitan component in the control formulation of the film was substituted with xanthan gum at concentrations between 0.01 and 0.04 % to analyze its effect on lipid dispersion. Scanning electron microscopy (SEM) showed a surface for the control (0 % xanthan) with good lipid distribution. However, when the samples were investigated by optical microscopy (OM), lipid globules in the control biofilm appeared larger and more dispersed in the matrix than in the other samples. Fourier transform infrared (FTIR) spectroscopy indicated that xanthan concentrations deeply affected C=O linkages from amide I group, as well as the functional N-H group of amide II of the zein structure. Other weak interactions of amide I and II with carboxylic acids and aliphatic compounds were also observed. UV/VIS analysis as well as transparency measurements indicated that the addition of xanthan to the film matrix lowered significantly its transparency properties. Overall, the addition of xanthan gum favoured lipid dispersion in the matrix, making biofilms more homogeneous, although less transparent.U ovom su radu ispitane morfološke i strukturne značajke biofilmova na bazi zeina. U formulaciju je umjesto sorbitana dodana ksantanska guma koncentracije od 0,01 do 0,04 %, kako bi se ispitao utjecaj ksantana na disperziju lipida u biofilmu. Pretražnom elektronskom mikroskopijom prikazan je dobar raspored lipida na površini kontrolnog uzorka biofilma (s 0 % ksantana), a optičkim je mikroskopom utvrđeno da su lipidni globuli veći i raspršeniji u matriksu kontrolnog uzorka nego u ostalim uzorcima. Fourierova transformirana infracrvena spektroskopija pokazala je da koncentracija ksantana bitno utječe na C=O vezu amidne skupine I i na funkcionalnu N-H skupinu amida II u zeinu. Također su utvrđene slabe interakcije amida I i II s karboksilnim kiselinama i alifatskim skupinama. UV/VIS analizom i mjerenjem transparentnosti filmova ustanovljeno je da dodatak ksantana matriksu znatno smanjuje transparentnost filma. Zaključeno je da dodatak ksantanske gume poboljšava disperziju lipida u matriksu i homogenost, a smanjuje transparentnost filmova

Morfološke i strukturne značajke biofilmova na bazi zeina s dodatkom ksantanske gume

Morphological and structural characteristics of zein-based biofilms have been studied in this work. The sorbitan component in the control formulation of the film was substituted with xanthan gum at concentrations between 0.01 and 0.04 % to analyze its effect on lipid dispersion. Scanning electron microscopy (SEM) showed a surface for the control (0 % xanthan) with good lipid distribution. However, when the samples were investigated by optical microscopy (OM), lipid globules in the control biofilm appeared larger and more dispersed in the matrix than in the other samples. Fourier transform infrared (FTIR) spectroscopy indicated that xanthan concentrations deeply affected C=O linkages from amide I group, as well as the functional N-H group of amide II of the zein structure. Other weak interactions of amide I and II with carboxylic acids and aliphatic compounds were also observed. UV/VIS analysis as well as transparency measurements indicated that the addition of xanthan to the film matrix lowered significantly its transparency properties. Overall, the addition of xanthan gum favoured lipid dispersion in the matrix, making biofilms more homogeneous, although less transparent.U ovom su radu ispitane morfološke i strukturne značajke biofilmova na bazi zeina. U formulaciju je umjesto sorbitana dodana ksantanska guma koncentracije od 0,01 do 0,04 %, kako bi se ispitao utjecaj ksantana na disperziju lipida u biofilmu. Pretražnom elektronskom mikroskopijom prikazan je dobar raspored lipida na površini kontrolnog uzorka biofilma (s 0 % ksantana), a optičkim je mikroskopom utvrđeno da su lipidni globuli veći i raspršeniji u matriksu kontrolnog uzorka nego u ostalim uzorcima. Fourierova transformirana infracrvena spektroskopija pokazala je da koncentracija ksantana bitno utječe na C=O vezu amidne skupine I i na funkcionalnu N-H skupinu amida II u zeinu. Također su utvrđene slabe interakcije amida I i II s karboksilnim kiselinama i alifatskim skupinama. UV/VIS analizom i mjerenjem transparentnosti filmova ustanovljeno je da dodatak ksantana matriksu znatno smanjuje transparentnost filma. Zaključeno je da dodatak ksantanske gume poboljšava disperziju lipida u matriksu i homogenost, a smanjuje transparentnost filmova

Detecção de bordas em imagens de ressonância magnética por meio de processamento de imagenscom algoritmos genéticos

A detecção de bordas em imagens digitais é uma etapa importante do processamento e análise de imagens, pois permite a localização dos objectos presentes nas mesmas, bem como a extracção de características importantes para o seu reconhecimento, tais como rugosidade da borda e dimensões e forma do objecto. Na tentativa de obter resultados mais precisos, viários métodos de detecção de bordas têm sido propostos. Neste trabalho, aborda-se a aplicação de algoritmos genéticos para detectar bordas de regiões anormais em imagens de ressonância magnética, com o objectivo de auxiliar no diagnóstico de tumores cerebrais. Os algoritmos genéticos são métodos de busca e optimização baseados na evolução dos seres vivos proposta por Charles Darwin, que declarou que os seres vivos adaptados ao seu ambiente são os que possuem maiores chances de sobreviver e gerar descendência. Estes algoritmos possuem duas estruturas básicas (genes e cromossomos) e três operações (selecção, cruzamento e mutação). Para ser aplicado em processamento de imagens, cada pixel é considerado um gene e os cromossomos um grupo de genes, ou seja, uma região com um determinado número de pixels. Os resultados obtidos neste trabalho mostraram-se animadores na detecção de tumores cerebrais de difícil diagnóstico visual, melhorando a visualização do mesmo pelo especialista médico

Prevalence of Common Mental Disorders in a Rural District of Kenya, and Socio-Demographic Risk Factors

Association between common mental disorders (CMDs), equity, poverty and socio-economic functioning are relatively well explored in high income countries, but there have been fewer studies in low and middle income countries, despite the considerable burden posed by mental disorders, especially in Africa, and their potential impact on development. This paper reports a population-based epidemiological survey of a rural area in Kenya. A random sample of 2% of all adults living in private households in Maseno, Kisumu District of Nyanza Province, Kenya (50,000 population), were studied. The Clinical Interview Schedule-Revised (CIS-R) was used to determine the prevalence of common mental disorders (CMDs). Associations with socio-demographic and economic characteristics were explored. A CMD prevalence of 10.8% was found, with no gender difference. Higher rates of illness were found in those who were of older age and those in poor physical health. We conclude that CMDs are common in Kenya and rates are elevated among people who are older, and those in poor health

Mental distress in the general population in Zambia: Impact of HIV and social factors

<p>Abstract</p> <p>Background</p> <p>Population level data on mental health from Africa are limited, but available data indicate mental problems to represent a substantial public health problem. The negative impact of HIV on mental health suggests that this could particularly be the case in high prevalence populations. We examined the prevalence of mental distress, distribution patterns and the ways HIV might influence mental health among men and women in a general population.</p> <p>Methods</p> <p>The relationship between HIV infection and mental distress was explored using a sample of 4466 participants in a population-based HIV survey conducted in selected rural and urban communities in Zambia in 2003. The Self-reporting questionnaire-10 (SRQ-10) was used to assess global mental distress. Weights were assigned to the SRQ-10 responses based on DSM IV criteria for depression and a cut off point set at 7/20 for probable cases of mental distress. A structural equation modeling (SEM) was established to assess the structural relationship between HIV infection and mental distress in the model, with maximum likelihood ratio as the method of estimation.</p> <p>Results</p> <p>The HIV prevalence was 13.6% vs. 18% in the rural and urban populations, respectively. The prevalence of mental distress was substantially higher among women than men and among groups with low educational attainment vs. high. The results of the SEM showed a close fit with the data. The final model revealed that self-rated health and self perceived HIV risk and worry of being HIV infected were important mediators between underlying factors, HIV infection and mental distress. The effect of HIV infection on mental distress was both direct and indirect, but was particularly strong through the indirect effects of health ratings and self perceived risk and worry of HIV infection.</p> <p>Conclusion</p> <p>These findings suggest a strong effect of HIV infection on mental distress. In this population where few knew their HIV status, this effect was mediated through self-perceptions of health status, found to capture changes in health perceptions related to HIV, and self-perceived risk and worry of actually being HIV infected.</p

Ureaplasma infections in pre-term infants: Recent information regarding the role of Ureaplasma species as neonatal pathogens

Although numerous clinical observational studies have been conducted over a period of over 30 years, the clinical significance of Ureaplasma infection is still under debate. The Ureaplasma speices. is a commensal in the female genital tract and considered to have of low virulence; however, Ureaplasma colonization has been associated with infertility, stillbirth, preterm delivery, histologic chorioamnionitis, and neonatal morbidities, including congenital pneumonia, meningitis, bronchopulmonary dysplasia, and perinatal death. Recently, Ureaplasma was subdivided into 2 separate species and 14 serovars. Ureaplasma parvum is known as biovar 1 and contains serovars 1, 3, 6, and 14, and Ureaplasma urealyticum (biovar 2) contains the remaining serovars (2, 4, 5, and 7-13). The existence of differences in pathogenicities of these 14 serovars and 2 biovars is controversial. Although macrolides are the only antimicrobial agents currently available for use in neonatal ureaplasmal infections, in the current clinical field, it is difficult to make decisions regarding which antibiotics should be used. Future investigations involving large, multicenter, randomized, controlled studies are needed before proper recommendations can be made for clinical practice