This paper describes a self-contained integrated microfluidic system that can separate motile sperm from small samples that are difficult to handle using conventional sperm-sorting techniques. The device isolates motile sperm from nonmotile sperm and other cellular debris, based on the ability of motile sperm to cross streamlines in a laminar fluid stream. The device is small, simple, and disposable yet is an integrated system complete with sample inlets, outlets, sorting channel, and a novel passively driven pumping system that provides a steady flow of liquid; it requires no external power source or controls. The device fulfills a need in clinical settings where small amounts of sperm need to be sorted. It also opens the way for convenient bioassays based on sperm motility including at-home motile sperm tests.

Study objective-Retrospective infant feeding data are important to the study of child and adult health patterns. The accuracy of maternal recall of past infant feeding events was examined and specifically the infant's age when breast feeding was stopped and formula feeding and solid foods were introduced.Design and setting-The sample consisted of Bedouin Arab women (n = 318) living in the Negev in Israel who were a part of a larger cohort participating in a prospective study of infant health and who were delivered of their infants between July 1 and December 15, 1981. Data from interviews conducted 12 and 18 months postpartum were compared to the standard data collected six months postpartum.Main results-As length of recall increased there was a small increase in the mean difference, and its standard deviation, between the standard and recalled age when breast feeding was stopped and formula feeding and solid foods were started. Recall on formula feeding was less accurate than recall on solid foods and breast feeding. In particular, among those 61% reporting formula use at the six month interview, 51% did not recall introducing formula when interviewed at 18 months. The odds ratio (95% CI) of stunting versus normal length for age for formula fed versus breast fed infants based on recall data (OR = 2-07; 95%CI 0O82-5 22) differed only slightly from those based on the standard data (OR = 2-21; 95%CI 0O77-6 37).

After 10 y of urban settlement, 680 Bedouin Arab children, who had had anthropometric assessment from birth (1981-1982) through early childhood, were reassessed in 1991-1992 to compare the rates of stunting in early and later childhood as well as to describe the factors influencing current height-for-age. Stunting had dropped from 32.7% at 18 mo to 7.2% at 10 y in the 1981 birth cohort and dropped from 17.5% at 9 mo to 8.2% at 9 y in the 1982 birth cohort. Based on a multiple-linear-regression analysis, height in early childhood and maternal height were statistically significantly and positively associated with current mean height-for-age in both cohorts. In the 1982 cohort socioeconomic status in early childhood was positively and current family size was negatively and significantly associated with current mean height-for-age. Thus, conditions that were present in early childhood had the largest influence on current height. In 1992, 10% and 6% of the infant siblings of the 1981 and 1982 cohorts, respectively, were stunted compared with 17% and 1% of the siblings aged 1-2 y of the respective cohorts. Therefore, the high rates of early childhood stunting in 1981-1982 appeared to be a birth cohort-specific phenomenon.

Two hundred seventy-four healthy Bedouin Arab newborns in 1981 were followed for 18 mo to examine the relationship between infant-feeding practices and growth during planned social change. Although wasting was not prevalent, the prevalence rate of stunting (less than or equal to -2 SDs) increased from 12% to 19% to 32% at 6, 12, and 18 mo, respectively. After multiple-logistic-regression adjustment for covariates, the odds ratio (OR) of stunting at 6 mo was reduced among infants breast-fed only or fed with supplement compared with weaned infants. Infant-feeding practices were not associated with stunting in later infancy; however, those stunted at 6 mo had an OR of 13 of stunting at 12 mo and those stunted at 12 mo had an OR of 14 of stunting at 18 mo. In a multiple-linear-regression analysis, seasonality, duration of breast-feeding, hospitalized morbidity, and residual of height at 6 mo were negatively associated with daily average linear growth from 6 to 12 mo; these factors only explained 12% of the variation in daily linear growth.

Women who breastfeed have frequently reported milk insufficiency as the reason for introducing the bottle, but no one has addressed its potential long-term health effects. This paper described the factors associated with milk insufficiency versus another reason for introducing the bottle and its potential health effects based on an analysis of a prospective cohort study of 1005 Bedouin Arab women who delivered healthy newborns in 1981 and 1982. By two months postpartum, 72% introduced the infant to the bottle with 72% reporting milk insufficiency as the reason for introducing the bottle. The percentage of milk insufficiency declined with increasing age of the infant. Based on multiple logistic regression analyses, birth season was statistically significantly associated with the odds ratio (OR) of milk insufficiency versus another reason for introducing the bottle during the first two months. Women who delivered in the spring-summer had an increased OR = 1.65 of reported milk insufficiency compared with those who delivered during the rest of the year. Parity was directly related to the OR = 1.04 of milk insufficiency (but just missed significance) during one to two months and was statistically significantly associated with the OR = 1.12 of reported milk insufficiency during 3-18 months. The rates of stunting after the infant was introduced to the bottle and the duration of breastfeeding did not differ by reason for introducing the bottle. Thus the high frequency of reported milk insufficiency was not associated with adverse health effects.