Contests with Bilateral Delegation: Unobservable Contracts

We study two-player contests in which, in order to win a prize, each player hires a delegate to expend effort on her behalf; neither party's delegation contract is revealed to the rival party when the delegates choose their effort levels. We obtain first the outcomes of this unobservable-contracts case. Next, we perform comparative statics of these outcomes with respect to the higher-valuation player's valuation for the prize. Finally, we compare the outcomes of the unobservable-contracts case with those of the observable-contracts case. We find, among other things, that the unobservability of delegation contracts narrows the gap between the delegates' equilibrium contingent compensation

Contests with Bilateral Delegation: Unobservable Contracts

We study two-player contests in which, in order to win a prize, each player hires a delegate to expend effort on her behalf; neither party's delegation contract is revealed to the rival party when the delegates choose their effort levels. We obtain first the outcomes of this unobservable-contracts case. Next, we perform comparative statics of these outcomes with respect to the higher-valuation player's valuation for the prize. Finally, we compare the outcomes of the unobservable-contracts case with those of the observable-contracts case. We find, among other things, that the unobservability of delegation contracts narrows the gap between the delegates' equilibrium contingent compensation

Group Size and Matching Protocol in Contests

We investigate the effects of group size and matching protocol in Tullock contest experiments. In a 2x2 factorial design we implement partner and random stranger matching protocols in contests between two and between three players. Group size does not affect overall absolute bid levels, but the rate of overbidding is lower in two-player groups across matching protocols. Matching protocol does not affect bidding behavior for three-player groups, but a partner matching reduces both the level and dispersion of bids in two-player groups. These results show the joint effect of group size and matching protocol, and suggest that identifiability in repeated play facilitates tacit collusion

Genome-wide expression patterns associated with oncogenesis and sarcomatous transdifferentation of cholangiocarcinoma

BACKGROUND: The molecular mechanisms of CC (cholangiocarcinoma) oncogenesis and progression are poorly understood. This study aimed to determine the genome-wide expression of genes related to CC oncogenesis and sarcomatous transdifferentiation. METHODS: Genes that were differentially expressed between CC cell lines or tissues and cultured normal biliary epithelial (NBE) cells were identified using DNA microarray technology. Expressions were validated in human CC tissues and cells. RESULTS: Using unsupervised hierarchical clustering analysis of the cell line and tissue samples, we identified a set of 342 commonly regulated (>2-fold change) genes. Of these, 53, including tumor-related genes, were upregulated, and 289, including tumor suppressor genes, were downregulated (<0.5 fold change). Expression of SPP1, EFNB2, E2F2, IRX3, PTTG1, PPARγ, KRT17, UCHL1, IGFBP7 and SPARC proteins was immunohistochemically verified in human and hamster CC tissues. Additional unsupervised hierarchical clustering analysis of sarcomatoid CC cells compared to three adenocarcinomatous CC cell lines revealed 292 differentially upregulated genes (>4-fold change), and 267 differentially downregulated genes (<0.25 fold change). The expression of 12 proteins was validated in the CC cell lines by immunoblot analysis and immunohistochemical staining. Of the proteins analyzed, we found upregulation of the expression of the epithelial-mesenchymal transition (EMT)-related proteins VIM and TWIST1, and restoration of the methylation-silenced proteins LDHB, BNIP3, UCHL1, and NPTX2 during sarcomatoid transdifferentiation of CC. CONCLUSION: The deregulation of oncogenes, tumor suppressor genes, and methylation-related genes may be useful in identifying molecular targets for CC diagnosis and prognosis

AM1638, a GPR40-Full Agonist, Inhibited Palmitate-Induced ROS Production and Endoplasmic Reticulum Stress, Enhancing HUVEC Viability in an NRF2-Dependent Manner

Background G protein-coupled receptor 40 (GPR40) is a key molecule in diabetes and fatty liver, but its role in endothelial dysfunction remains unclear. Our objective in this study was to determine whether GPR40 agonists protect endothelial cells against palmitatemediated oxidative stress. Methods Human umbilical vein endothelial cells (HUVECs) were used to investigate effects of various GPR40 agonists on vascular endothelium. Results In HUVECs, AM1638, a GPR40-full agonist, enhanced nuclear factor erythroid 2–related factor 2 (NRF2) translocation to the nucleus and heme oxygenase-1 (HO-1) expression, which blocked palmitate-induced superoxide production. Those antioxidant effects were not detected after treatment with LY2922470 or TAK875, GPR40-partial agonists, suggesting that GPR40 regulates reactive oxygen species (ROS) removal in a ligand-dependent manner. We also found that palmitate-induced CCAAT/enhancer‐binding protein homologous protein expression; X-box binding protein-1 splicing, nuclear condensation, and fragmentation; and caspase-3 cleavage were all blocked in an NRF2-dependent manner after AM1638 treatment. Both LY2922470 and TAK875 also improved cell viability independent of the NRF2/ROS pathway by reducing palmitate-mediated endoplasmic reticulum stress and nuclear damage. GPR40 agonists thus have beneficial effects against palmitate in HUVECs. In particular, AM1638 reduced palmitate-induced superoxide production and cytotoxicity in an NRF2/HO-1 dependent manner. Conclusion GPR40 could be developed as a good therapeutic target to prevent or treat cardiovascular diseases such as atherosclerosis

The First Korean Case of Beare-Stevenson Syndrome with a Tyr375Cys Mutation in the Fibroblast Growth Factor Receptor 2 Gene

Here we report the first case of a Korean infant with a cloverleaf-shaped craniosynostosis, in which the diagnosis of Beare-Stevenson syndrome was suspected upon observation of the typical morphological features. This infant exhibited craniofacial anomalies, ocular proptosis, cutis gyrata, acanthosis nigricans, prominent umbilical stump, furrowed palms and soles, hypospadia, and sacral skin tag coupled with dermal sinus tract. Brain magnetic resonance imaging revealed that the patient also had non-communicating hydrocephalus with Chiari malformation. This is the 8th report of Beare-Stevenson syndrome in the literature, which was confirmed by the detection of a Tyr375Cys mutation in the fibroblast growth factor receptor 2 (FGFR2) gene

Does Manufacturer Advertising Crowd-In or Crowd-Out Retailer Advertising? An Application of an Endogenous Prize Contest with Asymmetric Players

su¢ ciently large increases have a crowding-in e¤ect by &quot;jump-starting&quot;competition between retailers for the larger market. Furthermore, asymmetric abilities in such contests can lead the weaker player to e¤ectively drop out of the contest, thereby undermining the ability of increased prizes to increase e¤ort by intensifying competition. More generally the model can be applied to other contests such as patent races or promotion tournaments where not just the probability of winning but also the value of winning depends on contest e¤ort levels. JEL: C72, D7

Diode Laser—Can It Replace the Electrical Current Used in Endoscopic Submucosal Dissection?

Background/Aims A new medical fiber-guided diode laser system (FDLS) is expected to offer high-precision cutting with simultaneous hemostasis. Thus, this study aimed to evaluate the feasibility of using the 1,940-nm FDLS to perform endoscopic submucosal dissection (ESD) in the gastrointestinal tract of an animal model. Methods In this prospective animal pilot study, gastric and colorectal ESD using the FDLS was performed in ex vivo and in vivo porcine models. The completeness of en bloc resection, the procedure time, intraprocedural bleeding, histological injuries to the muscularis propria (MP) layer, and perforation were assessed. Results The en bloc resection and perforation rates in the ex vivo study were 100% (10/10) and 10% (1/10), respectively; those in the in vivo study were 100% (4/4) and 0% for gastric ESD and 100% (4/4) and 25% (1/4) for rectal ESD, respectively. Deep MP layer injuries tended to occur more frequently in the rectal than in the gastric ESD cases, and no intraprocedural bleeding occurred in either group. Conclusions The 1,940-nm FDLS was capable of yielding high en bloc resection rates without intraprocedural bleeding during gastric and colorectal ESD in animal models

Determination of Malignant and Invasive Predictors in Branch Duct Type Intraductal Papillary Mucinous Neoplasms of the Pancreas: A Suggested Scoring Formula

Prediction of malignancy or invasiveness of branch duct type intraductal papillary mucinous neoplasm (Br-IPMN) is difficult, and proper treatment strategy has not been well established. The authors investigated the characteristics of Br-IPMN and explored its malignancy or invasiveness predicting factors to suggest a scoring formula for predicting pathologic results. From 1994 to 2008, 237 patients who were diagnosed as Br-IPMN at 11 tertiary referral centers in Korea were retrospectively reviewed. The patients' mean age was 63.1 ± 9.2 yr. One hundred ninty-eight (83.5%) patients had nonmalignant IPMN (81 adenoma, 117 borderline atypia), and 39 (16.5%) had malignant IPMN (13 carcinoma in situ, 26 invasive carcinoma). Cyst size and mural nodule were malignancy determining factors by multivariate analysis. Elevated CEA, cyst size and mural nodule were factors determining invasiveness by multivariate analysis. Using the regression coefficient for significant predictors on multivariate analysis, we constructed a malignancy-predicting scoring formula: 22.4 (mural nodule [0 or 1]) + 0.5 (cyst size [mm]). In invasive IPMN, the formula was expressed as invasiveness-predicting score = 36.6 (mural nodule [0 or 1]) + 32.2 (elevated serum CEA [0 or 1]) + 0.6 (cyst size [mm]). Here we present a scoring formula for prediction of malignancy or invasiveness of Br-IPMN which can be used to determine a proper treatment strategy