Cervical facet capsular ligament yield defines the threshold for injury and persistent joint-mediated cervical pain

The cervical facet joint has been identified as a source of neck pain, and its capsular ligament is a likely candidate for injury during whiplash. Many studies have shown that the mechanical properties of ligaments can be altered by subfailure injury. However, the subfailure mechanical response of the facet capsular ligament has not been well defined, particularly in the context of physiology and pain. Therefore, the goal of this study was to quantify the structural mechanics of the cervical facet capsule and define the threshold for altered structural responses in this ligament during distraction. Tensile failure tests were preformed using isolated C6/C7 rat facet capsular ligaments (n=8); gross ligament failure, the occurrence of minor ruptures and ligament yield were measured. Gross failure occurred at 2.45±0.60 N and 0.92±0.17 mm. However, the yield point occurred at 1.68±0.56 N and 0.57±0.08 mm, which was significantly less than gross failure (p\u3c0.001 for both measurements). Maximum principal strain in the capsule at yield was 80±24%. Energy to yield was 14.3±3.4% of the total energy for a complete tear of the ligament. Ligament yield point occurred at a distraction magnitude in which pain symptoms begin to appear in vivo in the rat. These mechanical findings provide insight into the relationship between gross structural failure and painful loading for the facet capsular ligament, which has not been previously defined for such neck injuries. Findings also present a framework for more in-depth methods to define the threshold for persistent pain and could enable extrapolation to the human response

Vector Correlation Technique for Pixel-wise Detection of Collagen Fiber Realignment During Injurious Tensile Loading

Excessive soft tissue loading can produce adverse structural and physiological changes in the absence of any visible tissue rupture. However, image-based analysis techniques to assess microstructural changes during loading without any visible rupture remain undeveloped. Quantitative polarized light imaging (QPLI) can generate spatial maps of collagen fiber alignment during loading with high temporal resolution and can provide a useful technique to measure microstructural responses. While collagen fibers normally realign in the direction that tissue is loaded, rapid, atypical fiber realignment during loading may be associated with the response of a local collagenous network to fiber failure. A vector correlation technique was developed to detect this atypical fiber realignment using QPLI and mechanical data collected from human facet capsular ligaments (n=16) loaded until visible rupture. Initial detection of anomalous realignment coincided with a measurable decrease in the tissue stiffness in every specimen and occurred at significantly lower strains than those at visible rupture (ρ \u3c 0.004), suggesting this technique may be sensitive to a loss of microstructural integrity. The spatial location of anomalous realignment was significantly associated with regions where visible rupture developed (ρ \u3c 0.001). This analysis technique provides a foundation to identify regional differences in soft tissue injury tolerances and relevant mechanical thresholds

International Extension Curriculum: Strengthening Extension\u27s Capacity for International Engagement—Module 6: Exploring Cultural Perspective of Families

Families build the foundation of communities. As the demographic profiles of families in communities change, communities change. In order to design and deliver extension programs and services to effectively meet the needs of communities, it is important to understand the needs and wants of those who live there. This module can provide professional development to extension staff. However, activities in this module can also be used in extension programming to assist others in learning about the role of culture in families, how individuals can design and deliver programs and services.https://lib.dr.iastate.edu/hdfs_extensionpubs/1000/thumbnail.jp

Structural Changes in the Cervical Facet Capsular Ligament: Potential Contributions to Pain Following Subfailure Loading

While studies have demonstrated the cervical facet capsule is at risk for tensile injury during whiplash, the relationship between joint loading, changes in the capsule’s structure, and pain is not yet fully characterized. Complementary approaches were employed to investigate the capsule’s structure-function relationship in the context of painful joint loading. Isolated C6/C7 facet joints (n=8) underwent tensile mechanical loading, and measures of structural modification were compared for two distraction magnitudes: 300 μm (PV) and 700 μm (SV). In a matched in vivo study, C6/C7 facet joints (n=4) were harvested after the same SV distraction and the tissue was sectioned to analyze collagen fiber organization using polarized light microscopy. Laxity following SV distraction (7.30±3.01%) was significantly greater (p\u3c0.001) than that produced following PV distraction (0.99±0.44%). Also, SV distractions produced significantly higher maximum principal strain (p\u3c0.001) in the capsule and resulted in significantly greater decreases in stiffness (p=0.002) when compared to PV distraction. After SV distraction in vivo, mean angular deviation of the fiber direction (16.8±2.6º) was significantly increased (p=0.004) relative to naive samples in the lateral region of the capsule, indicating collagen fiber disorganization. These findings demonstrate that certain subfailure loading conditions are associated with altered joint mechanics and collagen fiber disorganization and imply ligament damage. Substructural damage in the capsule has the potential to both directly modulate nerve fiber signaling and produce sustained physiologic modifications that may initiate persistent pain

Quantifying the Origin and Distribution of Intracluster Light in a Fornax-like Cluster

Using a cosmological $N$-body simulation, we investigate the origin and distribution of stars in the intracluster light (ICL) of a Fornax-like cluster. In a dark matter only simulation we identify a halo which, at $z=0$, has $M_200 \simeq 4.1 \times 10^{13}M_{sun}$ and $r_{200} = 700kpc$, and replace infalling subhalos with models that include spheroid and disc components. As they fall into the cluster, the stars in some of these galaxies are stripped from their hosts, and form the ICL. We consider the separate contributions to the ICL from stars which originate in the haloes and the discs of the galaxies. We find that disc ICL stars are more centrally concentrated than halo ICL stars. The majority of the disc ICL stars are associated with one initially disc-dominated galaxy that falls to the centre of the cluster and is heavily disrupted, producing part of the cD galaxy. At radial distances greater than 200kpc, well beyond the stellar envelope of the cD galaxy, stars formerly from the stellar haloes of galaxies dominate the ICL. Therefore at large distances, the ICL population is dominated by older stars.Comment: Paper published as MNRAS , 2017, 467, 4501 This version corrects a small typo in the authors fiel

The Formation of a Realistic Disk Galaxy in Lambda Dominated Cosmologies

We simulate the formation of a realistic disk galaxy within the hierarchical scenario of structure formation and study its internal properties to the present epoch. We compare results from a LambdaCDM simulation with a LambdaWDM (2keV) simulation that forms significantly less small scale structure. We show how high mass and force resolution in both the gas and dark matter components play an important role in solving the angular momentum catastrophe claimed from previous simulations of galaxy formation within the hierarchical framework. The stellar material in the disk component has a final specific angular momentum equal to 40% and 90% of that of the dark halo in the LambdaCDM and LambdaWDM models respectively. The LambdaWDM galaxy has a drastically reduced satellite population and a negligible stellar spheroidal component. Encounters with satellites play only a minor role in disturbing the disk. Satellites possess a variety of star formation histories linked to mergers and pericentric passages along their orbit around the primary galaxy. In both cosmologies, the galactic halo retains most of the baryons accreted and builds up a hot gas phase with a substantial X-ray emission. Therefore, while we have been successful in creating a realistic stellar disk in a massive galaxy within the LambdaCDM scenario, energy injection emerges as necessary ingredient to reduce the baryon fraction in galactic halos, independent of the cosmology adopted. (abridged)Comment: ApJ in press. Images and movies at http://hpcc.astro.washington.edu/faculty/fabio/galform.html Significantly expanded revised version. (9 pages vs the original 4

The Photo Essay: A Visual Research Method for Educating Obstetricians and Other Health Care Professionals

When it comes to issues related to low-income women seeking early, adequate, or continuous prenatal ca re, the public health and medical communities continue to tell women to take responsibility for their actions. Rarely are messages aimed at providers. To help physicians see how factors in their offices and clinics can affect service utilization, the photo essay, a visual qualitative research strategy was developed using low- income minority and disenfranchised women who had recently given birth or were near to giving birth. Eight photo essays were completed. Together, the narratives, in collaboration with the photos, provided an opportunity for physicians to hear and observe women, as consumers, as they expanded their descriptions of their prenatal care experience

The Formation of Polar Disk Galaxies

Polar Ring Galaxies, such as NGC4650A, are a class of galaxy which have two kinematically distinct components that are inclined by almost 90 degrees to each other. These striking galaxies challenge our understanding of how galaxies form; the origin of their distinct components has remained uncertain, and the subject of much debate. We use high-resolution cosmological simulations of galaxy formation to show that Polar Ring Galaxies are simply an extreme example of the angular moment misalignment that occurs during the hierarchical structure formation characteristic of Cold Dark Matter cosmology. In our model, Polar Ring Galaxies form through the continuous accretion of gas whose angular momentum is misaligned with the central galaxy.Comment: Submitted to ApJ. 8 pages in emulate ApJ style. 2 associated animations are found at: http://www.youtube.com/watch?v=c-H3WzaewdY http://www.youtube.com/watch?v=9Xf3fJkgWE

Carbohydrate antigens in nipple aspirate fluid predict the presence of atypia and cancer in women requiring diagnostic breast biopsy

<p>Abstract</p> <p>Background</p> <p>The goal of this prospective study was to determine (a) concentrations of the carbohydrate biomarkers Thomsen Friedenreich (TF) antigen and its precursor, Tn antigen, in nipple discharge (ND) collected from women requiring biopsy because of a suspicious breast lesion; and (b) if concentration levels predicted pathologic diagnosis.</p> <p>Methods</p> <p>Adult women requiring biopsy to exclude breast cancer were enrolled and ND obtained. The samples from 124 women were analyzed using an anti-TF and anti-Tn monoclonal antibodies in direct immunoassay.</p> <p>Results</p> <p>The highest median concentration in ND for TF and Tn was in women with ductal carcinoma <it>in situ </it>(DCIS). TF was higher in women with 1) cancer (DCIS or invasive) vs. either no cancer (atypia or benign pathology, p = .048), or benign pathology (p = .018); and 2) abnormal (atypia or cancer) versus benign pathology (p = .016); and was more predictive of atypia or cancer in post- compared to premenopausal women. Tn was not predictive of disease. High TF concentration and age were independent predictors of disease, correctly classifying either cancer or abnormal vs. benign pathology 83% of the time in postmenopausal women.</p> <p>Conclusions</p> <p>TF concentrations in ND were higher in women with precancer and cancer compared to women with benign disease, and TF was an independent predictor of breast atypia and cancer. TF may prove useful in early breast cancer detection.</p