Single-cell RNA sequencing reveals placental response under environmental stress.

The placenta is crucial for fetal development, yet the impact of environmental stressors such as arsenic exposure remains poorly understood. We apply single-cell RNA sequencing to analyze the response of the mouse placenta to arsenic, revealing cell-type-specific gene expression, function, and pathological changes. Notably, the Prap1 gene, which encodes proline-rich acidic protein 1 (PRAP1), is significantly upregulated in 26 placental cell types including various trophoblast cells. Our study shows a female-biased increase in PRAP1 in response to arsenic and localizes it in the placenta. In vitro and ex vivo experiments confirm PRAP1 upregulation following arsenic treatment and demonstrate that recombinant PRAP1 protein reduces arsenic-induced cytotoxicity and downregulates cell cycle pathways in human trophoblast cells. Moreover, PRAP1 knockdown differentially affects cell cycle processes, proliferation, and cell death depending on the presence of arsenic. Our findings provide insights into the placental response to environmental stress, offering potential preventative and therapeutic approaches for environment-related adverse outcomes in mothers and children.

Immigration Restrictions as Active Labor Market Policy: Evidence from the Mexican Bracero Exclusion.

An important class of active labor market policy has received little impact evaluation: immigration barriers intended to raise wages and employment by shrinking labor supply. Theories of endogenous technical advance raise the possibility of limited or even perverse impact. We study a natural policy experiment: the exclusion of almost half a million Mexican 'bracero' farm workers from the United States to improve farm labor market conditions. With novel archival data we measure state-level exposure to exclusion, and model the labor-market effect in the absence of technical change. We reject such an effect and fail to reject a null effect.

Validity and Intrarater Reliability of 2-Dimensional Motion Analysis Using a Handheld Tablet Compared to Traditional 3-Dimensional Motion Analysis.

CONTENT: Lower extremity landing mechanics have been implicated as a contributing factor in knee pain and injury, yet cost effective and clinically accessible methods for evaluating movement mechanics are limited. The identification of valid, reliable, and readily accessible technology to assess lower extremity alignment could be an important tool for clinicians, coaches, and strength and conditioning specialists. OBJECTIVE: The purpose of this study was to examine the validity and reliability of using a hand-held tablet and movement analysis application (app) for assessing lower extremity alignment during a drop vertical jump task. DESIGN: Concurrent Validation. SETTING: Laboratory. PARTICIPANTS: Twenty-two healthy college aged subjects (11 female and 11 male, mean age = 21 ± 1.4 years; mean height: 1.73 ± .12 m, mean mass: 71 ± 13 kg) with no lower extremity pathology that prevented safe landing from a drop jump. INTERVENTION: Subjects performed six drop vertical jumps which were recorded simultaneously using a 3D motion capture system and a hand-held tablet. MAIN OUTCOME MEASURES: Angles on the tablet were calculated using a motion analysis app and from the 3D motion capture system using Visual 3D. Hip and knee angles were measured and compared between both systems. RESULTS: Significant correlations between the tablet and 3D measures for select frontal and sagittal plane ranges of motion (ROM) and angles at maximum knee flexion (MKF) ranged from r = 0.48 (P = .036) for frontal plane knee angle at MKF to r = .77 (P<.001) for knee flexion at MKF. CONCLUSION: Results of this study suggest that a hand-held tablet and app may be a reliable method for assessing select lower extremity joint alignments during drop vertical jumps, but this technology should not be used to measure absolute joint angles. However, sports medicine specialists could use a hand-held tablet to reliably record and evaluate lower extremity movement patterns on the field or in the clinic.