Women's Economic Mobility and Small for Gestational Age Rates: The Effect of Paternal Early-Life Socioeconomic Position.

OBJECTIVE: To determine whether paternal early-life socioeconomic position (defined by neighborhood income) modifies the association of maternal economic mobility and infant small for gestational age (weight for gestational age < 10th percentile, SGA) rates. METHODS: Stratified and multilevel binomial regression analyses were executed on the Illinois transgenerational dataset of parents (born 1956-1976) and their infants (born 1989-1991) with appended U.S. census income information. Only Chicago-born women with an early-life residence in impoverished or affluent neighborhoods were studied. RESULTS: The incidence of impoverished-born women's upward economic mobility among births (n = 3777) with early-life low socioeconomic position (SEP) fathers was less than that of those (n = 576) with early-life high SEP fathers: 56% vs 71%, respectively, p < 0.01. The incidence of affluent-born women's downward economic mobility among births (n = 2370) with early-life low SEP fathers exceeded that of those (n = 3822) with early-life high SEP fathers: 79% vs 66%, respectively, p < 0.01. The adjusted RR of infant SGA for maternal upward (compared to lifelong impoverishment) economic mobility among fathers with early-life low and high SEP equaled 0.68 (0.56, 0.82) and 0.81 (0.47, 1.42), respectively. The adjusted RR of infant SGA for maternal downward (compared to lifelong residence in affluent neighborhoods) economic mobility among fathers with early-life low and high SEP were 1.37 (0.91, 2.05) and 1.17 (0.86, 1.59), respectively. CONCLUSIONS: Paternal early-life SEP is associated with maternal economic mobility (both upward and downward); however, it does not modify the relationship between maternal economic mobility and infant SGA rates.

Ergodic and nonergodic processes coexist in the plasma membrane as observed by single-molecule tracking.

Diffusion in the plasma membrane of living cells is often found to display anomalous dynamics. However, the mechanism underlying this diffusion pattern remains highly controversial. Here, we study the physical mechanism underlying Kv2.1 potassium channel anomalous dynamics using single-molecule tracking. Our analysis includes both time series of individual trajectories and ensemble averages. We show that an ergodic and a nonergodic process coexist in the plasma membrane. The ergodic process resembles a fractal structure with its origin in macromolecular crowding in the cell membrane. The nonergodic process is found to be regulated by transient binding to the actin cytoskeleton and can be accurately modeled by a continuous-time random walk. When the cell is treated with drugs that inhibit actin polymerization, the diffusion pattern of Kv2.1 channels recovers ergodicity. However, the fractal structure that induces anomalous diffusion remains unaltered. These results have direct implications on the regulation of membrane receptor trafficking and signaling.

Simulation of a theta line-scanning confocal microscope.

We describe a 2-D computational model of the optical propagation of coherent light from a laser diode within human skin to better understand the performance of a confocal reflectance theta microscope. The simulation uses finite-difference time domain (FDTD) computations to solve Maxwell's equations in a synthetic skin model that includes melanin, mitochondria, and nuclei. The theta line-scanning confocal microscope configuration experiences more localized decreases in the signal than the confocal common-path point-scanning microscope. We hypothesize that these decreases result from the bistatic imaging configuration, the imaging geometry, and the inhomogeneity of the index of refraction of the skin. All these factors result in the source path having aberrations different than those of the receiver path. The model predicts signal decreases that are somewhat greater than those seen in experiments. New details on the reflection from a spherical object show that imaging with the theta line scanner leads to somewhat different results than would be seen with a common-path point scanner. The model is used to optimize the design of the theta line-scanning confocal microscope.