Induction of insulin-like growth factor 2 expression in a mesenchymal cell line co-cultured with an ameloblast cell line

Various growth factors have been implicated in the regulation of cell proliferation and differentiation during tooth development. It has been unclear if insulin-like growth factors (IGFs) participate in the epithelium–mesenchyme interactions of tooth development. We previously produced three-dimensional sandwich co-culture systems (SW) containing a collagen membrane that induce the differentiation of epithelial cells. In the present study, we used the SW system to analyze the expression of IGFs and IGFRs. We demonstrate that IGF2 expression in mesenchymal cells was increased by SW. IGF1R transduces a signal; however, IGF2R does not transduce a signal. Recombinant IGF2 induces IGF1R and IGF2R expression in epithelial cells. IGF1R expression is increased by SW; however, IGF2R expression did not increase by SW. Thus, IGF2 signaling works effectively in SW. These results suggest that IGF signaling acts through the collagen membrane on the interaction between the epithelium and mesenchyme. In SW, other cytokines may be suppressed to induce IGF2R induction. Our results suggest that IGF2 may play a role in tooth differentiation

Liver-Derived IGF-I Regulates Mean Life Span in Mice

Background: Transgenic mice with low levels of global insulin-like growth factor-I (IGF-I) throughout their life span, including pre- and postnatal development, have increased longevity. This study investigated whether specific deficiency of liver-derived, endocrine IGF-I is of importance for life span. Methods and Findings: Serum IGF-I was reduced by approximately 80 % in mice with adult, liver-specific IGF-I inactivation (LI-IGF-I-/- mice), and body weight decreased due to reduced body fat. The mean life span of LI-IGF-I-/- mice (n = 84) increased 10 % vs. control mice (n = 137) (Cox’s test, p,0.01), mainly due to increased life span (16%) of female mice [LI-IGF-I-/- mice (n = 31): 26.761.1 vs. control (n = 67): 23.060.7 months, p,0.001]. Male LI-IGF-I-/- mice showed only a tendency for increased longevity (p = 0.10). Energy expenditure, measured as oxygen consumption during and after submaximal exercise, was increased in the LI-IGF-I-/- mice. Moreover, microarray and RT-PCR analyses showed consistent regulation of three genes (heat shock protein 1A and 1B and connective tissue growth factor) in several body organs in the LI-IGF-I-/- mice. Conclusions: Adult inactivation of liver-derived, endocrine IGF-I resulted in moderately increased mean life span. Body weight and body fat decreased in LI-IGF-I-/- mice, possibly due to increased energy expenditure during exercise. Genes earlier reported to modulate stress response and collagen aging showed consistent regulation, providing mechanisms tha

An Analysis of Factors Contributing to Wins in the National Hockey League

This thesis looks at common factors that have the largest impact on winning games in the NHL. Data was collected from regular season games for all teams in the NHL over seven seasons. Logistic and least squares regressions were performed to create a win probability model and a goal margin model to predict the outcome of games. Discriminant analysis was also used to determine significant factors over the course of an entire season. Save percentage margin, shot margin, block margin, short-handed shot margin, short-handed faceoff percentage, and even-handed faceoff percentage were found to be significant influences on individual game wins. Total goals, total goals against and takeaway totals for a season were enough to correctly predict whether a team made the playoffs 87% of the time. The accuracies of the models were then tested by predicting the outcome of games from the 2012 NHL regular season

A Study of Influential Statistics Associated with Success in the National Football League

This dissertation considers the most important aspects of success in the National Football League (NFL). Success is defined, for this paper, as winning individual games in the short term, and making the playoffs over the course of a season in the long term. Data was collected for 750 different regular season games over the course of five seasons in the NFL, and used to create models that identify those factors which are most significant towards winning at both the short term and long term levels. A point spread model was developed using an ordinary least squares regression method, and stepwise selection technique to reduce the number of variables included. Logistic regression models were also created to state the probability a team will win an individual game, and also the probability a team will make the playoffs at the end of the season. Discriminant analysis was performed to compare the significant variables in our models, and determine which had the largest influence. We considered the relationship between offense and defense in the NFL to conclude whether or not one area had a significant advantage over the other. We also fit a proportional odds model on the data set to categorize blowout games, and those that are close at the end. The overwhelming presence of turnover margin, passing efficiency, first down margin, and sack yardage in all of our models is clear evidence that there are a handful of statistics that can explain success in the NFL. Using the statistics from games, we were able to correctly identify the winner around 88% of the time. Finally, we used simulations and historical team performances to forecast future game outcomes, our models classified the actual winner with a 71% accuracy rate. Analytics are slowly gaining momentum in football, and the advantages are clear. Quantifying success in the NFL can benefit both individual teams, and the league as a whole, to present the best possible product to their audiences

Statistical Tests Exploring a Subset of Variables Related to Weather Balloon Burst Altitude

The ability to accurately estimate balloon burst altitude is important when modeling flight paths in preparation for a high altitude balloon launch. Variables considered for the study of burst altitude include the manufacturer of the balloon, the time of day of the flight, and the volume change of the balloon during the last ten minutes before burst. To study these variables, we ran statistical tests on data collected from more than sixty balloon flights carried out by researchers across America

Statistical Tests Exploring a Subset of Variables Related to Weather Balloon Burst Altitude

The ability to accurately estimate balloon burst altitude is important when modeling flight paths in preparation for a high altitude balloon launch. Variables considered for the study of burst altitude include the manufacturer of the balloon, the time of day of the flight, and the volume change of the balloon during the last ten minutes before burst. To study these variables, we ran statistical tests on data collected from more than sixty balloon flights carried out by researchers across America

Growth hormone is permissive for skeletal adaptation to mechanical loading

The Lewis dwarf (DW) rat was used as a model to test the hypothesis that growth hormone (GH) is permissive for new bone formation induced by mechanical loading in vivo. Adult female Lewis DW rats aged 6.2 +/- 0.1 months (187 +/- 18 g) were allocated to four vehicle groups (DW), four GH treatment groups at 32.5 mug/100 g body mass (DWGH1), and four GH treatment groups at 65 mug/100 g (DWGH2). Saline vehicle or GH was injected intraperitoneally (ip) at 6:30 p.m. and 6:30 a.m. before mechanical loading of tibias at 7:30 a.m. A single period of 300 cycles of four-point bending was applied to right tibias at 2.0 Hz, and magnitudes of 24, 29, 38, or 48N were applied. Separate strain gauge analyses in 5 DW rats validated the selection of loading magnitudes. After loading, double-label histomorphometry was used to assess bone formation at the periosteal surface (Ps.S) and endocortical surface (Ec.S) of tibias. Comparing left (unloaded) tibias among groups, GH treatment had no effect on bone formation. Bone formation in tibias in DW rats was insensitive to mechanical loading. At the Ec.S, mechanically induced lamellar bone formation increased in the DWGH2 group loaded at 48N (p < 0.05), and no significant increases in bone formation were observed among other groups. The percentage of tibias expressing woven bone formation (Wo.B) at the Ps.S was significantly greater in the DWGH groups compared with controls (p < 0.05). We concluded that GH influences loading-related bone formation in a permissive manner and modulates the responsiveness of bone tissue to mechanical stimuli by changing thresholds for bone formation

Classifying Mixing Regimes in Ponds and Shallow Lakes

Lakes are classified by thermal mixing regimes, with shallow waterbodies historically categorized as continuously mixing systems. Yet, recent studies demonstrate extended summertime stratification in ponds, underscoring the need to reassess thermal classifications for shallow waterbodies. In this study, we examined the summertime thermal dynamics of 34 ponds and shallow lakes across temperate North America and Europe to categorize and identify the drivers of different mixing regimes. We identified three mixing regimes: rarely (n = 18), intermittently (n = 10), and often (n = 6) mixed, where waterbodies mixed an average of 2%, 26%, and 75% of the study period, respectively. Waterbodies in the often mixed category were larger (≥4.17 ha) and stratification weakened with increased wind shear stress, characteristic of “shallow lakes.” In contrast, smaller waterbodies, or “ponds,” mixed less frequently, and stratification strengthened with increased shortwave radiation. Shallow ponds (\u3c0.74 m) mixed intermittently, with daytime stratification often breaking down overnight due to convective cooling. Ponds ≥0.74 m deep were rarely or never mixed, likely due to limited wind energy relative to the larger density gradients associated with slightly deeper water columns. Precipitation events weakened stratification, even causing short-term mixing (hours to days) in some sites. By examining a broad set of shallow waterbodies, we show that mixing regimes are highly sensitive to very small differences in size and depth, with potential implications for ecological and biogeochemical processes. Ultimately, we propose a new framework to characterize the variable mixing regimes of ponds and shallow lakes