Shear-induced damped oscillations in an epithelium depend on actomyosin contraction and E-cadherin cell adhesion.

Shear forces between cells occur during global changes in multicellular organization during morphogenesis and tissue growth, yet how cells sense shear forces and propagate a response across a tissue is unknown. We found that applying exogenous shear at the midline of an epithelium induced a local, short-term deformation near the shear plane, and a long-term collective oscillatory movement across the epithelium that spread from the shear-plane and gradually dampened. Inhibiting actomyosin contraction or E-cadherin trans-cell adhesion blocked oscillations, whereas stabilizing actin filaments prolonged oscillations. Combining these data with a model of epithelium mechanics supports a mechanism involving the generation of a shear-induced mechanical event at the shear plane which is then relayed across the epithelium by actomyosin contraction linked through E-cadherin. This causes an imbalance of forces in the epithelium, which is gradually dissipated through oscillatory cell movements and actin filament turnover to restore the force balance across the epithelium

Stable, covalent attachment of laminin to microposts improves the contractility of mouse neonatal cardiomyocytes.

The mechanical output of contracting cardiomyocytes, the muscle cells of the heart, relates to healthy and disease states of the heart. Culturing cardiomyocytes on arrays of elastomeric microposts can enable inexpensive and high-throughput studies of heart disease at the single-cell level. However, cardiomyocytes weakly adhere to these microposts, which limits the possibility of using biomechanical assays of single cardiomyocytes to study heart disease. We hypothesized that a stable covalent attachment of laminin to the surface of microposts improves cardiomyocyte contractility. We cultured cells on polydimethylsiloxane microposts with laminin covalently bonded with the organosilanes 3-glycidoxypropyltrimethoxysilane and 3-aminopropyltriethoxysilane with glutaraldehyde. We measured displacement of microposts induced by the contractility of mouse neonatal cardiomyocytes, which attach better than mature cardiomyocytes to substrates. We observed time-dependent changes in contractile parameters such as micropost deformation, contractility rates, contraction and relaxation speeds, and the times of contractions. These parameters were affected by the density of laminin on microposts and by the stability of laminin binding to micropost surfaces. Organosilane-mediated binding resulted in higher laminin surface density and laminin binding stability. 3-glycidoxypropyltrimethoxysilane provided the highest laminin density but did not provide stable protein binding with time. Higher surface protein binding stability and strength were observed with 3-aminopropyltriethoxysilane with glutaraldehyde. In cultured cardiomyocytes, contractility rate, contraction speeds, and contraction time increased with higher laminin stability. Given these variations in contractile function, we conclude that binding of laminin to microposts via 3-aminopropyltriethoxysilane with glutaraldehyde improves contractility observed by an increase in beating rate and contraction speed as it occurs during the postnatal maturation of cardiomyocytes. This approach is promising for future studies to mimic in vivo tissue environments

An analysis of integrative outcomes in the Dayton peace negotiations

The nature of the negotiated outcomes of the eight issues of the Dayton Peace Agreement was studied in terms of their integrative and distributive aspects. in cases where integrative elements were Sound, further analysis was conducted by concentrating on Pruitt's five types of integrative solutions: expanding the pie, cost cutting, non-specific compensation, logrolling, and bridging. The results showed that real world international negotiations can arrive at integrative agreements even when they involve redistribution of resources tin this case the redistribution of former Yugoslavia). Another conclusion was that an agreement can consist of several distributive outcomes and several integrative outcomes produced by different kinds of mechanisms. Similarly, in single issues more than one mechanism can be used simultaneously. Some distributive bargaining was needed in order to determine how much compensation was required. Finally, each integrative formula had some distributive aspects as well

tt-Martin boundary of killed random walks in the quadrant

We compute the $t$-Martin boundary of two-dimensional small steps random walks killed at the boundary of the quarter plane. We further provide explicit expressions for the (generating functions of the) discrete $t$-harmonic functions. Our approach is uniform in $t$, and shows that there are three regimes for the Martin boundary.Comment: 18 pages, 2 figures, to appear in S\'eminaire de Probabilit\'e

Adverse Birth Outcomes of adolescent and Young adult Women Diagnosed With Cancer During Pregnancy

BACKGROUND: We examined adverse birth outcomes among adolescent and young adult women diagnosed with cancer (AYA women, ages 15-39 years) during pregnancy. METHODS: We linked data from the Texas Cancer Registry, vital records, and Texas Birth Defects Registry to identify all singleton births to AYA women diagnosed during pregnancy from January 1999 to December 2016. We compared prevalence of adverse live birth outcomes between AYA women and women without cancer (matched 1:4 on age, race and ethnicity, and year). Among AYA women, we used log-binomial regression to identify factors associated with these outcomes. Statistical tests were 2-sided. RESULTS: AYA women had 1271 singleton live births and 20 stillbirths. AYA women (n = 1291) were 33.3% Hispanic and 9.8% non-Hispanic Black and most commonly had breast (22.5%), thyroid (19.8%), and gynecologic (13.3%) cancers. Among live births, AYA women had a higher prevalence of low birth weight offspring (30.1% vs 9.0%), very preterm (5.7% vs 1.2%), and preterm birth (25.1% vs 7.2%); cesarean delivery (44.3% vs 35.2%); and low Apgar score (2.7% vs 1.5%), compared with women without cancer (n = 5084) (all P \u3c .05). Prevalence of any birth defect by age 12 months did not statistically differ (5.2% vs 4.7%; P = .48), but live births to AYA women more often had heart and circulatory system defects (2.2% vs 1.3%; P = .01). In adjusted models, cancer type and chemotherapy were associated with adverse live birth outcomes. CONCLUSIONS: AYA women diagnosed during pregnancy have higher prevalence of adverse birth outcomes and face difficult decisions in balancing treatment risks and benefits

Estimating Flood Frequency in Gaged and Ungaged Watersheds

Proceedings of the 1999 Georgia Water Resources Conference, March 30 and 31, Athens, Georgia.Estimation of flood frequency is important in jurisdictional wetlands determination and functional assessment, stream classification and restoration, and in assessing urban and agricultural risk in flood prone areas. For example, in utilizing the hydrogeomorphic approach (HGM) for wetland functional assessment for riverine wetlands, the flood frequency variable is required in seven of the suite of fifteen functions. However, site-specific determination of flood frequency has been difficult, especially in ungaged watersheds. One promising method is development of regional dimensionless rating curves. The curves are derived from stage/discharge and channel geometric relationships associated with gaged watersheds. Once the curves are constructed and calibrated to a specific region, flood frequency and channel geometry can be estimated at any point within ungaged as well as gaged watersheds within that region. This method was employed to calibrate the flood frequency variable in the low gradient, riverine HGM guidebook applicable to Western Kentucky. Flood frequency and discharge were determined at several riverine reference wetlands for the purpose of assessing wetland function throughout the Western Kentucky Coalfield Physiographic Region.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Ecology, The University of Georgia, Athens, Georgia 30602-2202 with partial funding provided by the U.S. Department of Interior, geological Survey, through the Georgia Water Research Insttitute as authorized by the Water Research Institutes Authorization Act of 1990 (P.L. 101-397). The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of the University of Georgia or the U.S. Geological Survey or the conference sponsors

Association of Myostatin on Performance and Carcass Traits in Crossbred Cattle

Calf-fed steers and yearling heifersgenotyped as homozygous active, heterozygous, or homozygous inactive for myostatin were used to evaluate performance and carcass traits from Piedmontese influenced cattle. Homozygous inactive steers had similar ADG, lower DMI and lower F:G when compared to steers influenced by active myostatin. Steers and heifers with inactive myostatin showed similar trends in carcass traits producing larger LM area, greater dressing percentages and leaner carcasses. Similar ADG, lower DMI, and improved F:G were observed for homozygous inactive compared to homozygous active steers. Cattle with inactive myostatin require more days on feed than homozygous active cattle to reach similar live BW and 12th rib fat endpoints

Association of Myostatin on Performance and Carcass Traits in Crossbred Cattle

Calf-fed steers and yearling heifersgenotyped as homozygous active, heterozygous, or homozygous inactive for myostatin were used to evaluate performance and carcass traits from Piedmontese influenced cattle. Homozygous inactive steers had similar ADG, lower DMI and lower F:G when compared to steers influenced by active myostatin. Steers and heifers with inactive myostatin showed similar trends in carcass traits producing larger LM area, greater dressing percentages and leaner carcasses. Similar ADG, lower DMI, and improved F:G were observed for homozygous inactive compared to homozygous active steers. Cattle with inactive myostatin require more days on feed than homozygous active cattle to reach similar live BW and 12th rib fat endpoints