Associations of the digit ratio with adolescent behavior problems are inconsistent with an intrauterine androgenic origin.

A low second-to-fourth digit ratio (2D:4D) is a purported biomarker of increased intrauterine androgenic exposure, presumably linked to postnatal behavior. We aimed to examine the associations between 2D:4D and adolescence behavior problems expected from high (externalizing and attention problems) or low (internalizing problems) prenatal androgen exposure. We conducted a cross-sectional study of 1042 Colombian schoolchildren aged 11-18 y. We examined whether caliper-assessed 2D:4D was associated with behavior problems per the Youth Self-Report questionnaire. Mean problem standardized score point differences were estimated between hand- and sex-specific quintiles of 2D:4D with use of multivariable linear regression. Lower right-hand 2D:4D was associated with decreased externalizing and internalizing behavior problem scores. Corresponding lowest-to-median quintile adjusted mean differences (95% CI) were -4.6 (-7.5, -1.7) and -3.5 (-6.4, -0.6) points in boys; and -3.4 (-5.9, -0.9) and -3.5 (-6.2, -0.8) points in girls. Lower right-hand 2D:4D was also related to less attention and thought problems in boys, and to less social problems among girls. Associations were nonlinear, apparent only below 2D:4D medians, and stronger with the right than the left hand. In conclusion, right-hand 2D:4D is related to behavior problems in adolescence in directions that are not fully consistent with an androgenic exposure origin.

Difference in Bioimpedance Across the Knee in Un-Injured Young Adults.

Background: Knee injuries induce swelling and resolution of swelling may be a useful factor in identifying states of healing and time to return to sports activities. Recent work has suggested that bioimpedance can provide an objective measure of swelling following total knee arthroplasty (TKA) and therefore may also provide guidance for clinical decision-making following knee injury. This study measures knee bioimpedance in young, active people to help define baseline variability and factors that influence limb to limb differences. Methods: Bioimpedance was measured via sensors placed at the foot/ankle and thigh, in positions similar to those suggested for monitoring post-TKA swelling. Initial tests were performed to verify method repeatability, then bioimpedance was measured in a convenience sample of 78 subjects (median age 21yrs). The influence of age, BMI, thigh circumference, and knee function (KOOS-JR) on the impedance measures and difference in impedance between the subject's knees were examined using a generalized multivariable linear regression. Results: The repeatability study measurements were highly consistent with a COV of 1.5% for resistance and an ICC of 97.9%. Women exhibited significantly larger dominant limb impedance and larger limb to limb difference in impedance than men. Regression analysis indicated that subject sex and BMI significantly influenced bioimpedance but joint score and age did not. The limb to limb differences in impedance were small on average (<5%), with larger magnitudes of difference associated with female sex, lower knee function scores, and larger limb to limb differences in thigh circumference. Conclusion: Bioimpedance measurements across right and left knees of healthy young people were similar, supporting use of bioimpedance measures from a patient's uninjured knee as a benchmark to monitor healing of a contralateral injured knee. Future work should focus on understanding how knee function scores and bioimpedance are related, and further explore how sex and side to side anatomic differences impact the measurement. Level of Evidence: IV.

Empirical correlations for diffusivity and the partition coefficient for phthalates in PVC materials and modelling emissions of automotive sealants.

Polyvinylchloride (PVC) based sealants commonly contain phthalate plasticizers that are emitted into the air over time. The low volatility classifies them as Semi-Volatile Organic Compounds (SVOCs). Empirical relationships are determined for estimation of the diffusion and solid/air partition coefficients for phthalates in PVC materials using data compiled from studies of phthalates in other PVC materials, such as vinyl flooring. The relationships are functions of vapor pressure of the compounds, which are determined from a Clausius-Clapeyron equation. A test chamber was constructed to continuously sample the air and measure the air concentration based on a Solid Phase MicroExtraction (SPME) method. The partition coefficient was tested with dioctyl terephthalate (DOTP) in a PVC-based sealant, in which the results fell within the reasonable error of the value predicted from the empirical relationship. The model is applied to outdoor and manufacturing scenarios to evaluate the effect of temperature and mass transfer coefficient.

Analysis of restraint use in pregnant versus non-pregnant populations involved in motor vehicle collisions.

BACKGROUND: Traumatic injuries obtained by pregnant females in motor vehicle collisions present unique treatment challenges for trauma and orthopaedic surgeons. Understanding safety choices in this population can help physicians and public safety advocates in delivering effective and targeted safety messages. METHODS: A publicly available, de-identified national data set that documents crash information (NASS-CDS) was examined to identify cohorts of pregnant and non-pregnant vehicle occupants and regression analysis employed to identify factors associated with belt non-use. RESULTS: Pregnant women were found to have significantly lower rates of belt use compared to non-pregnant females (70.0% vs. 90.3%, Rao-Scott Sample Weighted Chi-Square p = 0.0265). Logistic regression identified younger age and sitting in the back seat as associated with lower rates of belt use. CONCLUSION: Pregnant women wear belts at significantly lower frequencies than non-pregnant women and youth and second row seating increase noncompliance rates. This work suggests the need for targeted intervention strategies to improve belt compliance.

α1b-Adrenergic Receptor Localization and Relationship to the D1-Dopamine Receptor in the Rat Nucleus Accumbens.

The α1-adrenergic receptors (α1ARs) have been implicated in numerous actions of the brain, including attention and wakefulness. Additionally, they have been identified as contributing to disorders of the brain, such as drug addiction, and recent work has shown a role of these receptors in relapse to psychostimulants. While some functionality is known, the actual subcellular localization of the subtypes of the α1ARs remains to be elucidated. Further, their anatomical relationship to receptors for other neurotransmitters, such as dopamine (DA), remains unclear. Therefore, using immunohistochemistry and electron microscopy techniques, this study describes the subcellular localization of the α1b-adrenergic receptor (α1bAR), the subtype most tied to relapse behaviors, as well as its relationship to the D1-dopamine receptor (D1R) in both the shell and core of the rat nucleus accumbens (NAc). Overall, α1bARs were found in unmyelinated axons and axon terminals with some labeling in dendrites. In accordance with other studies of the striatum, the D1R was found mainly in dendrites and spines; therefore, colocalization of the D1R with the α1bAR was rare postsynaptically. However, in the NAc shell, when the receptors were co-expressed in the same neuronal elements there was a trend for both receptors to be found on the plasma membrane, as opposed to the intracellular compartment. This study provides valuable anatomical information about the α1bAR and its relationship to the D1R and the regulation of DA and norepinephrine (NE) neurotransmission in the brain which have been examined previously.