[A follow-up study on the introduction of vegetables and fruits during infants aged 4-8 months in Beijing and Chenzhou City of Hunan Province].

OBJECTIVE: To investigate the introduction of vegetables and fruits in 4-8 months old infants, and to describe the maternal and infants' characteristics associated with the introduction of vegetables and fruits. METHODS: Mother-infant dyads (n=228) were recruited from 12 to 16 weeks postpartum and formally entered the study at 4 months of age. Data collected via face to face interview at 4-8 months postpartum, including the timing and types of added vegetables and fruits, as well as a variety of maternal and infant characteristics (n=204). Rank sum test and multiple linear regression were used to analyze the maternal and infant characteristics related to the introduction of vegetables and fruits. RESULTS: The time of introducing vegetables was concentrated at the age of 7 months, and the time of adding fruits was mainly at 6 months. Fruits were added earlier than vegetables (P < 0.001), and the variety of the added fruits was higher than that of vegetables (P=0.045). 48% (n=98) of infants had no more than three types of fruits and vegetables at 8 months. Only 9.8% (n=20) had added more than 10 kinds of fruits and vegetables at 8 months. Green leafy vegetables were the most commonly added vegetable, and apple was the most popular fruit. Compared with women who were 35 years of age or younger, women beyond 35 years old introduced vegetables to their babies 0.6 months later. 4-month-old exclusively breastfed infants had vegetables 0.4 months later than mixed-fed infants. Women with a bachelor's degree or above added 2-3 more types of fruits and vegetables to their babies than those with junior high school education and below. CONCLUSION: The adding time of fruits was earlier than that of vegetable. Apples and green leafy vegetables are commonly added. Women with lower educational backgrounds add fewer types of fruits and vegetables to their babies. Mothers who choose exclusive breastfeeding and those over 35 years of age at childbirth add vegetables to their babies later than others. They should be targeted for health promotion programs that aim to improve the intake of fruits and vegetables among infants.

Cell encapsulation with alginate and alpha-phenoxycinnamylidene-acetylated poly(allylamine).

In general, microcapsules prepared from alginate and polycations lack mechanical strength because the interaction between alginate and polycations is ionic instead of covalent, which represents a much stronger bond. To increase the mechanical strength of the capsule, we prepared photosensitive microcapsules that could form covalent bonds between polymers in the capsular membrane by light irradiation. Two types of photosensitive poly(allylamine), with 5% and 10% of amino groups modified by alpha-phenoxycinnamylidene acetylchloride, were synthesized. Both photopolymers exhibited an absorption maximum at 325 nm and were capable of crosslinking upon light exposure. These photosensitive polymers were used for the preparation of microcapsules. The capsules formed from this photosensitive poly(allylamine) and alginate were strengthened significantly by light irradiation. Only 28% of the microcapsules prepared from the 5%-modified photopolymer fractured after 48 h of shaking at 150 rpm. This fracture percentage is much lower when compared with the 60% of capsules fractured when prepared from the untreated poly(allylamine). By using poly(allylamine) at 10% modification, the mechanical strength was improved only slightly, with 26% of capsules fractured. Analysis of the permeability test indicated that the photo-crosslinked capsular membrane was freely permeable to cytochrome c and myoglobin, but less permeable to serum albumin. The encapsulation method was used to entrap and culture IW32 mouse leukemia cells. The cells proliferated to a density of about 1.1 x 10(7) cells/mL in the capsules after 7 days of cultivation. Concurrently, the concentration of erythropoietin in the microcapsules increased to 800 mU/mL. This new encapsulation technique has great potential in the application of a bioindustrial cell-culturing process.

A novel cell encapsulation method using photosensitive poly(allylamine alpha-cyanocinnamylideneacetate).

A photosensitive alpha-cyanocinnamylideneacetyl group was coupled to poly(allylamine) to obtain a photosensitive polymer. This photosensitive poly(allylamine alpha-cyanocinnamylideneacetate) can cross-link upon light exposure. Microcapsules were fabricated from alginate in contact with Ca+2 ion, followed by coating with the photosensitive poly(allylamine alpha-cyanocinnamylideneacetate). The microcapsules, thus formed, can be strengthened significantly by the light-induced cross-linking of poly(allylamine alpha-cyanocinnamylideneacetate). Only 16 capsules (out of 50) prepared from the photosensitive poly(allylamine alpha-cyanocinnamylideneacetate) fractured after 48 h of agitation. For microcapsules prepared from the unmodified poly(allylamine), 32 capsules fractured. The photo cross-linked capsular membrane was permeable to cytochrome C, moderately permeable to myoglobin, and least permeable to serum albumin. IW32 (a mouse leukaemia cell line) cells were entrapped and cultured within these microcapsules. The cells proliferated to a density of about 9 x 10(6) cells/ml in the capsules after 7 days of cultivation.