Finite size corrections to the radiation reaction force in classical electrodynamics

We introduce an effective field theory approach that describes the motion of finite size objects under the influence of electromagnetic fields. We prove that leading order effects due to the finite radius $R$ of a spherically symmetric charge is order $R^2$ rather than order $R$ in any physical model, as widely claimed in the literature. This scaling arises as a consequence of Poincar\'e and gauge symmetries, which can be shown to exclude linear corrections. We use the formalism to calculate the leading order finite size correction to the Abraham-Lorentz-Dirac force.Comment: 4 pages, 2 figure

On working memory and a productivity illusion in distracted driving.

[EN]Drivers claim to use cell phones for benefits such as getting work done and to increase productivity (Sanbonmatsu, Strayer, Behrends, Medeiros-Ward, & Watson, in press). However, individuals who use cell phones while driving may be more likely to rely on reconstructive processes in memory due to divided attention, making them more susceptible to errors, yielding an ironic effect of multitasking that, in fact, may diminish productivity rather than increase it. To test this possibility, the present study included three within-subject conditions: single-task driving in a high-fidelity simulator, single-task memory including encoding and retrieval using the Deese–Roediger–McDermott false memory paradigm (Deese, 1959; Roediger & McDermott, 1995), and a dual-task combination of both the driving and memory tasks. The effects of divided attention in working memory were bidirectional, impairing both driving and episodic memory performance, likely due to competition for limited resources needed to successfully maintain task goals related to driving or memory alone. More specifically, under dual-task conditions, participants became increasingly reliant on reconstructive, error-prone processes in memory, with high levels of false recall. Taken together, these results indicate there is a productivity illusion associated with distracted driving in that individuals wrongly believe that combining cell phones with driving will make them more productive. Results are discussed in relation to theories of working memory and the domain-free ability to maintain task goals and to avoid distractions, whether this interference occurs in more traditional lab tasks or in more applied settings, highlighting the value of such converging evidence in sharpening theories of attention. (PsycInfo Database Record (c) 2022 APA, all rights reserved

Dysregulation of microRNA expression drives aberrant DNA hypermethylation in basal-like breast cancer

Basal-like breast cancers frequently express aberrant DNA hypermethylation associated with concurrent silencing of specific genes secondary to DNMT3b overexpression and DNMT hyperactivity. DNMT3b is known to be post-transcriptionally regulated by microRNAs. The objective of the current study was to determine the role of microRNA dysregulation in the molecular mechanism governing DNMT3b overexpression in primary breast cancers that express aberrant DNA hypermethylation. The expression of microRNAs (miRs) that regulate (miR-29a, miR-29b, miR-29c, miR-148a and miR-148b) or are predicted to regulate DNMT3b (miR-26a, miR-26b, miR-203 and miR-222) were evaluated among 70 primary breast cancers (36 luminal A-like, 13 luminal B-like, 5 HER2-enriched, 16 basal-like) and 18 normal mammoplasty tissues. Significantly reduced expression of miR-29c distinguished basal-like breast cancers from other breast cancer molecular subtypes. The expression of aberrant DNA hypermethylation was determined in a subset of 33 breast cancers (6 luminal A-like, 6 luminal B-like, 5 HER2-enriched and 16 basal-like) through examination of methylation-sensitive biomarker gene expression (CEACAM6, CDH1, CST6, ESR1, GNA11, MUC1, MYB, TFF3 and SCNN1A), 11/33 (33%) cancers exhibited aberrant DNA hypermethylation including 9/16 (56%) basal-like cancers, but only 2/17 (12%) non-basal-like cancers (luminal A-like, n=1; HER2-enriched, n=1). Breast cancers with aberrant DNA hypermethylation express diminished levels of miR-29a, miR-29b, miR-26a, miR-26b, miR-148a and miR-148b compared to cancers lacking aberrant DNA hypermethylation. A total of 7/9 (78%) basal-like breast cancers with aberrant DNA hypermethylation exhibit diminished levels of ≥6 regulatory miRs. The results show that i) reduced expression of miR-29c is characteristic of basal-like breast cancers, ii) miR and methylation-sensitive gene expression patterns identify two subsets of basal-like breast cancers, and iii) the subset of basal-like breast cancers with reduced expression of multiple regulatory miRs express aberrant DNA hypermethylation. Together, these findings strongly suggest that the molecular mechanism governing the DNMT3b-mediated aberrant DNA hypermethylation in primary breast cancer involves the loss of post-transcriptional regulation of DNMT3b by regulatory miRs

Patient Perceptions of Planned Organ Removal During Hysterectomy

Purpose: Previous reports indicate many women may not have a firm grasp on likely outcomes of different hysterectomy procedures. This study aimed to assess women’s self-reported expectations of how they think their anatomy will change after hysterectomy. Methods: Women scheduled for hysterectomy at a tertiary care hospital, for non-oncological reasons, reported their planned procedure type and the organs they understood would be removed 2 weeks prior to surgery. Patient reports and electronic medical records were reviewed, and kappa statistics (κ) were calculated to assess agreement for all women and within subgroups. Results: Most of the 456 study participants (mean age: 48.02 ± 8.29 years) were either white/Caucasian (n = 238, 52.2%) or African American (n = 196, 43.0%). Among the 145 participants who reported a partial hysterectomy, 130 (89.7%) women indicated that their uterus would be removed and 52 (35.9%) reported that their cervix would be removed. Of those whose response was total hysterectomy (n = 228), 208 (91.2%) participants reported their uterus would be removed and 143 (62.7%) reported their cervix would be removed. Among 144 women reporting a planned partial hysterectomy, only 15 (10.4%, κ = 0.05) had a partial hysterectomy recorded in the electronic medical record. Among the 228 women who reported a planned total hysterectomy, 6.1% (κ = 0.05) had a different procedure. While 125 participants reported planned ovary removal, only 93 (74.4%, κ = 0.55) had an oophorectomy. Similarly, 290 participants reported planned fallopian tube removal, with 276 (95.2%, κ = 0.06) having a salpingectomy. Conclusions: A considerable proportion of women undergoing hysterectomy do not accurately report the organs that are planned be removed during their hysterectomy. This work demonstrates the need to improve patient understanding of their clinical care and its implications

Parkland, September 30, 1987

https://spark.parkland.edu/prospectus_1987/1020/thumbnail.jp

Hematogenous Metastasis of Ovarian Cancer: Rethinking Mode of Spread

SummaryOvarian cancer has a clear predilection for metastasis to the omentum, but the underlying mechanisms involved in ovarian cancer spread are not well understood. Here, we used a parabiosis model that demonstrates preferential hematogenous metastasis of ovarian cancer to the omentum. Our studies revealed that the ErbB3-neuregulin 1 (NRG1) axis is a dominant pathway responsible for hematogenous omental metastasis. Elevated levels of ErbB3 in ovarian cancer cells and NRG1 in the omentum allowed for tumor cell localization and growth in the omentum. Depletion of ErbB3 in ovarian cancer impaired omental metastasis. Our results highlight hematogenous metastasis as an important mode of ovarian cancer metastasis. These findings have implications for designing alternative strategies aimed at preventing and treating ovarian cancer metastasis

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Tau Causes Synapse Loss without Disrupting Calcium Homeostasis in the rTg4510 Model of Tauopathy

Neurofibrillary tangles (NFTs) of tau are one of the defining hallmarks of Alzheimer’s disease (AD), and are closely associated with neuronal degeneration. Although it has been suggested that calcium dysregulation is important to AD pathogenesis, few studies have probed the link between calcium homeostasis, synapse loss and pathological changes in tau. Here we test the hypothesis that pathological changes in tau are associated with changes in calcium by utilizing in vivo calcium imaging in adult rTg4510 mice that exhibit severe tau pathology due to over-expression of human mutant P301L tau. We observe prominent dendritic spine loss without disruptions in calcium homeostasis, indicating that tangles do not disrupt this fundamental feature of neuronal health, and that tau likely induces spine loss in a calcium-independent manner