Styrylquinolinium borates as donor–acceptor initiators for sensitized photopolymerization of TMPTA

Several photoredox pairs containing mono- and bicationic hemicyanine dyes have been evaluated as photoinitiators for free radical polymerization induced with an argon-ion laser irradiation. The tested photoredox couples are the pairs composed of the hemicyanine dye cations acting as electron acceptors and n-butyltriphenyl borate anions being the electron donors. The photoinitiating abilities of the series of monochromophoric stilbazolium borates, 4-(p-N,N-dialkylaminostyryl)quinolinium n-butyltriphenylborate, were compared to the photochemistry of structurally related, bicationic styrylquinolinium borates. The obtained results clearly documented that the dicationic photoinitiators exhibit a marked increase in the photoinitiation ability compared to the initiators consisting of a single charged hemicyanine dye.Our studies revealed also that the rate of photopolymerization depends on ΔG_el of electron transfer between borate anion and styrylquinolinium cation. The relationship between the rate of polymerization and the free energy of activation shows the dependence predicted by the classical theory of electron transfer.     

Constraints on good child-care practices and nutritional status in urban Dar-es-Salaam, Tanzania

BACKGROUND: Care is increasingly being recognized as a crucial input to child health and nutrition, along with food security, availability of health services, and a healthy environment. Although significant gains have been made in the fight against malnutrition in Tanzania, the nutritional status of preschool children in urban areas is not improving. OBJECTIVE: To assess child-care practices and the nutritional status of infants and young children with the aim of improvingfeeding practices and child nutritional status. METHODS: A cross-sectional study was undertaken in urban Dar-es-Salaam, Tanzania. The study involved 100 randomly selected mothers of children 6 to 24 months old from households in Ilala Municipality, one of the three municipalities that constitute the Dar-es-Salaam City Council. Data were collected by a structured questionnaire, spot-check observations, and anthropometric measurements. RESULTS: The prevalence rates of stunting, underweight, wasting, and morbidity were 43%, 22%, 3%, and 80%, respectively. The prevalence of exclusive breastfeeding was very low (9%), and most stunted children (88%) were not exclusively breastfed for the first 6 months. The mean age at which complementary foods and fluids were introduced was 3.26 +/- 1.12 months (range, 1 to 5 months). The fluids given were mainly water and thin cereal-based porridge. More than half of the households practiced good hygiene. Most of the psychosocial practices (e.g., caregiver's attention, affection, and involvement in child feeding, hygiene, health care, and training) were performed by mothers, except for cooking and feeding the children and child training, which were done mostly by alternative caregivers. Nearly half of the mothers (44%) worked out of the home. The mean number of working hours per day was long (10.32 +/- 2.13), necessitating the use of alternative caregivers. A negative correlation was found between height-for-age z-scores and the number of hours mothers worked outside the home. CONCLUSIONS: The prevalence rates of chronic malnutrition and morbidity are high, and child-feeding practices are inadequate in this urban population. Maternal employment and educational characteristics constrain good child-care practices, and alternative caregivers are taking a more important role in child care as mothers join the work force. We recommend that formative research be conducted to study the actual practices of caregivers in order to form the basis for a child-care education program. There is also a need to strengthen national health system support for improved child feeding.     

Spring Inserts for the Intensification of the Heat Exchange Process during Boiling in Vertical Tubes——Optimization of Geometric Parameters

The paper presents new criteria for calculation of heat transfer coefficients and flow resistance during boiling inside vertical tubes with spring inserts, developed on the basis of own experimental research. Calculations of the geometric parameters of the spring insert were carried out using the Nelder-Mead optimization method for various optimization criteria (maximizing the increase ratios for heat transfer coefficient and flow resistance, minimizing entropy, own optimization criterion). The results of optimization calculations were verified by the optimization procedures available in Statistica.     

7-Ketocholesterol and 7-hydroxycholesterol in pork meat and its gravy thermally treated without additives and in the presence of onion and garlic

The effect of onion and garlic on the formation of two cholesterol oxidation products (COPs): 7-ketocholesterol and 7-hydroxycholesterol was evaluated by comparing their concentrations in meat and gravy samples obtained from three pork dishes prepared in the presence and absence of these flavourings. The concentration of these compounds in meat samples was between 82.4 and 1331.6 ng/g of cooked meat. Gravies contained lower amounts: from 18.3 to 45.6 ng/g of cooked meat. The addition of onion (30 g/100 g of meat) caused a decrease in 7-ketocholesterol and 7-hydroxycholesterol concentrations in all of the investigated pork dishes by 9.5–79%, whilst the addition of 15 g of garlic to 100 g of meat lowered the concentration by 17 to 88%. The greatest decrease was found in grilled minced chops. The quantitative assessment of 7-ketocholesterol and 7-hydroxycholesterol was carried out by thin-layer chromatography with densitometric detection.