Emergent dynamics of fairness in the spatial coevolution of proposer and responder species in the ultimatum game

While spatially local interactions are ubiquitous between coevolving species sharing recourses (e.g., plant-insect interactions), their effects on such coevolution processes of strategies involving the share of a resource are still not clearly understood. We construct a two-dimensional spatial model of the coevolution of the proposer and responder species in the ultimatum game (UG), in which a pair of proposer and responder individuals at each site plays the UG. We investigate the effects of the locality of interactions and the intensity of selection on the emergence of fairness between these species. We show that the lower intensity of selection favors fair strategies in general, and there are no significant differences in the evolution of fairness between the cases with local and global interactions when the intensity of selection is low. However, as the intensity of selection becomes higher, the spatially local interactions contribute to the evolution of fairer strategies more than the global interactions, even though fair strategies become more difficult to evolve. This positive effect of spatial interactions is expected to be due to the mutual benefit of fairness for both proposer and responder species in future generations, which brings about a dynamic evolution process of fairness.

Digitized detection of gamma-ray signals concentrated in narrow time windows for transient positron annihilation lifetime spectroscopy

A pulsed slow-positron beam generated by an electron linear accelerator was directly used for positron annihilation lifetime spectroscopy without any positron storage devices. A waveform digitizer was introduced to simultaneously capture multiple gamma-ray signals originating from positron annihilation events during a single accelerator pulse. The positron pulse was chopped and bunched with the chopper signals also sent to the waveform digitizer. Time differences between the annihilation gamma-ray and chopper peaks were calculated and accumulated as lifetime spectra in a computer. The developed technique indicated that positron annihilation lifetime spectroscopy can be performed in a 20 μs time window at a pulse repetition rate synchronous with the linear accelerator. Lifetime spectra of a Kapton sheet and a thermally grown SiO2 layer on Si were successfully measured. Synchronization of positron lifetime measurements with pulsed ion irradiation was demonstrated by this technique.

Development and Validation of LC-MS/MS Assay for the Quantification of Progesterone in Rat Plasma and its Application to Pharmacokinetic Studies

A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of progesterone levels in rat plasma. Progesterone-d9 was used as an internal standard (IS). Samples were prepared using salting-out assisted liquid/liquid extraction (SALLE), and the extracts were injected directly onto the LC-MS/MS system. The chromatographic separation was achieved on a CAPCELL PAK C18 MGIII column (100 mm × 2.0 mm, i.d. 5 µm) using methanol and aqueous 0.1% formic acid solution gradient as the mobile phase with a constant flow rate of 0.45 mL/min. Electrospray ionization in the positive-ion mode was employed. Multiple reaction monitoring of the precursor to product ion pairs, from m/z 315.20 to m/z 109.10 for progesterone and from m/z 324.26 to m/z 113.07 for the IS, was used for quantification. Good linearity was observed over the concentration range of 0.05-20.00 ng/mL with a weighted (1/x(2)) linear regression. The intra- and inter-day precision (% relative standard deviation [RSD]) across 3 validation days over the entire concentration range was lower than 6.7%. Accuracy (% nominal) determined at 5 quality control concentrations was between 94.0 and 103.7%. The validation method was applied in a pharmacokinetic study evaluating progesterone levels after intramuscular or vaginal administration to ovariectomized (OVX) rats. The area under the plasma concentration-time curve (AUC) calculated after intramuscular administration was more than 4 times higher than the AUC measured following vaginal administration of a comparable dose.

Phosphorylation of Smad2/3 at the specific linker threonine residue indicates slow-cycling esophageal stem-like cells before re-entry to the cell cycle

The stem cell compartment in the esophageal epithelium is possibly located in the basal layer. We have identified significant expression of Smad2/3, phosphorylated at specific linker threonine residues (pSmad2/3L-Thr), in the epithelial cells of murine stomach and intestine, and have suggested that these cells are epithelial stem cells. In this study, we explore whether pSmad2/3L-Thr could serve as a biomarker for esophageal stem cells. We examined esophageal tissues from normal C57BL/6 mice and those with esophagitis. Double immunofluorescent staining of pSmad2/3L-Thr with Ki67, CDK4, p63, or CK14 was performed. After immunofluorescent staining, we stained the same sections with hematoxylin-eosin and observed these cells under a light microscope. We used the 5-bromo-2-deoxyuridine (BrdU) labeling assay to examine label retention of pSmad2/3L-Thr immunostaining-positive cells. We collected specimens 5, 10, 15 and 20 days after repeated BrdU administrations and observed double immunofluorescent staining of pSmad2/3L-Thr with BrdU. In the esophagus, pSmad2/3L-Thr immunostaining-positive cells were detected in the basal layer. These cells were detected between Ki67 immunostaining-positive cells, but they were not co-localized with Ki67. pSmad2/3L-Thr immunostaining-positive cells showed co-localization with CDK4, p63, and CK14. Under a light microscope, pSmad2/3L-Thr immunostaining-positive cells indicated undifferentiated morphological features. Until 20 days follow-up period, pSmad2/3L-Thr immunostaining-positive cells were co-localized with BrdU. pSmad2/3L-Thr immunostaining-positive cells significantly increased in the regeneration phase of esophagitis mucosae, as compared with control mice (esophagitis vs.

CONTROL

6.889 ± 0.676/cm vs. 4.293 ± 0.659/cm; P < 0.001). We have identified significant expression of pSmad2/3L-Thr in the specific epithelial cells of murine esophagi. We suggest that these cells are slow-cycling epithelial stem-like cells before re-entry to the cell cycle.

Impact of pretransplant body mass index on the clinical outcome after allogeneic hematopoietic SCT

To elucidate the impact of pretransplant body mass index (BMI) on the clinical outcome, we performed a retrospective study with registry data including a total of 12 050 patients (age ⩾18 years) who received allogeneic hematopoietic SCT (HSCT) between 2000 and 2010. Patients were stratified as follows: BMI<18.5 kg/m(2), Underweight, n=1791; 18.5⩽BMI<25, Normal, n=8444; 25⩽BMI<30, Overweight, n=1591; BMI⩾30, Obese, n=224. The median age was 45 years (range, 18-77). A multivariate analysis showed that the risk of relapse was significantly higher in the underweight group and lower in the overweight and obese groups compared with the normal group (hazard ratio (HR), 1.16, 0.86, and 0.74, respectively). The risk of GVHD was significantly higher in the overweight group compared with the normal group. The risk of non-relapse mortality (NRM) was significantly higher in the overweight and obese group compared with the normal group (HR 1.19 and HR 1.43, respectively). The probability of OS was lower in the underweight group compared with the normal group (HR 1.10, P=0.018). In conclusion, pretransplant BMI affected the risk of relapse and NRM after allogeneic HSCT. Underweight was a risk factor for poor OS because of an increased risk of relapse. Obesity was a risk factor for NRM.

Valley-dependent spin polarization in bulk MoS2 with broken inversion symmetry

The valley degree of freedom of electrons is attracting growing interest as a carrier of information in various materials, including graphene, diamond and monolayer transition-metal dichalcogenides. The monolayer transition-metal dichalcogenides are semiconducting and are unique due to the coupling between the spin and valley degrees of freedom originating from the relativistic spin-orbit interaction. Here, we report the direct observation of valley-dependent out-of-plane spin polarization in an archetypal transition-metal dichalcogenide--MoS2--using spin- and angle-resolved photoemission spectroscopy. The result is in fair agreement with a first-principles theoretical prediction. This was made possible by choosing a 3R polytype crystal, which has a non-centrosymmetric structure, rather than the conventional centrosymmetric 2H form. We also confirm robust valley polarization in the 3R form by means of circularly polarized photoluminescence spectroscopy. Non-centrosymmetric transition-metal dichalcogenide crystals may provide a firm basis for the development of magnetic and electric manipulation of spin/valley degrees of freedom.

Emergence of a dynamic resource partitioning based on the coevolution of phenotypic plasticity in sympatric species

This paper investigates the coevolutionary dynamics of the phenotypic plasticity in the context of overlap avoidance behaviors of shared niches in sympatric species. Especially, we consider whether and how a differentiation of phenotypic plasticity can emerge under the assumption that there are no initial asymmetric relationships among coevolving species. We construct a minimal model where several different species participate in a partitioning of their shared niches, and evolve their behavioral plasticity to avoid an overlap of their niche use. By conducting evolutionary experiments with various conditions of the number of species and niches, we show that the two different types of asymmetric distributions of phenotypic plasticity emerge depending on the settings of the degree of congestion of the shared niches. In both cases, all species tended to obtain the similar amount of fitness regardless of such differences in their plasticity. We also show that the emerged distributions are coevolutionarily stable in general.

Positron annihilation in cardo-based polymer membranes

Positron annihilation lifetime spectroscopy (PALS) is applied to a series of bis(aniline)fluorene and bis(xylidine)fluorene-based cardo polyimide and bis(phenol)fluorene-based polysulfone membranes. It was found that favorable amounts of positronium (Ps, the positron-electron bound state) form in cardo polyimides with the 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) moiety and bis(phenol)fluorene-based cardo polysulfone, but no Ps forms in most of the polyimides with pyromellitic dianhydride (PMDA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BTDA) moieties. A bis(xylidine)fluorene-based polyimide membrane containing PMDA and BTDA moieties exhibits a little Ps formation but the ortho-positronium (o-Ps, the triplet state of Ps) lifetime of this membrane anomalously shortens with increasing temperature, which we attribute to chemical reaction of o-Ps. Correlation between the hole size (V(h)) deduced from the o-Ps lifetime and diffusion coefficients of O2 and N2 for polyimides with the 6FDA moiety and cardo polysulfone showing favorable Ps formation is discussed based on free volume theory of gas diffusion. It is suggested that o-Ps has a strong tendency to probe larger holes in rigid chain polymers with wide hole size distributions such as those containing cardo moieties, resulting in deviations from the previously reported correlations for common polymers such as polystyrene, polycarbonate, polysulfone, and so forth.

Effects of Ecological Inheritance on Coevolution of Cooperative Behaviors and Physically Niche Constructing Behaviors

Niche construction is a process whereby organisms that modify their own or others’ niches through their ecological activities. Recent studies have revealed that changes in social structures of interactions caused by social niche construction of individuals can affect seriously the evolution of cooperation. However, such a social niche also could be changed indirectly by a modification of their physical environment. Our purpose is to clarify the coevolution of cooperative behavior and physically niche-constructing behavior that modifies social niche indirectly. For this purpose, we constructed an evolutionary model in which each individual has not only a strategy for a spatial Prisoner’s Dilemma but also has traits for a niche-constructing behavior for modifying its physical environment that can limit social interactions between neighboring individuals. By conducting evolutionary experiments, we show that a cyclic coevolution between cooperative behavior and niche-constructing behavior occurred in the situation with no or low degree of ecological inheritance, in which the constructed niche could not be inherited in succeeding generations at all. Conversely, when the degree of ecological inheritance was high, the evolution of cooperation was promoted by the emerged environmental structure constructed by the evolved niche-constructing behavior. We also show that the condition for each scenario to occur depends on the settings of the payoff parameters as well as the degree of ecological inheritance.

Dobutamine stress echocardiography for assessment of systolic function in dogs with experimentally induced mitral regurgitation

Background

Systolic dysfunction is associated with poor outcomes in dogs with myxomatous mitral valve disease. However, assessment of systolic variables by conventional echocardiographic methods is difficult in these dogs because of mitral regurgitation (MR).

Hypothesis

We hypothesized that assessment of systolic function by dobutamine stress may identify systolic dysfunction in dogs with MR, and that 2‐dimensional speckle‐tracking echocardiography (2D‐STE) could quantitatively evaluate myocardial function.

Animals

Anesthetized dogs with experimentally induced MR.

Methods

Dogs were examined for systolic myocardial deformations using 2D‐STE during dobutamine infusion before and 3 and 6 months after MR induction. We evaluated peak systolic rotation and rotation rate in each basal and apical view; peak systolic torsion and torsion rate were also calculated.

Results

Invasive peak positive first derivatives of left ventricular pressure (dp/dt) were significantly decreased in dogs 6 months after induction of MR compared with pre‐MR results. After 3 and 6 months of MR, dogs had diminished peak systolic torsion values and torsion rates in response to dobutamine infusion compared with pre‐MR results (3 months, P < .001 and P = .006; 6 months, P = .003 and P = .021). These results were significantly correlated with overall invasive dp/dt (r = 0.644, P < .001; r = 0.696, P < .001).

Conclusions and Clinical Importance

Decreased torsion during dobutamine infusion in dogs with MR may reflect latent systolic dysfunction. Dobutamine infusion, therefore, may be useful for the assessment of systolic function in dogs with MR.

Continuing increased risk of oral/esophageal cancer after allogeneic hematopoietic stem cell transplantation in adults in association with chronic graft-versus-host disease

BACKGROUND

The number of long-term survivors after hematopoietic stem cell transplantation (HSCT) showed steady increase in the past two decades. Second malignancies after HSCT are a devastating late complication. We analyzed the incidence of, risk compared with that in the general population, and risk factors for secondary solid cancers.

PATIENTS AND METHODS

Patients were 17 545 adult recipients of a first allogeneic stem cell transplantation between 1990 and 2007 in Japan. Risks of developing secondary solid tumors were compared with general population by using standard incidence ratios (SIRs).

RESULTS

Two-hundred sixty-nine secondary solid cancers were identified. The cumulative incidence was 0.7% [95% confidence interval (CI), 0.6%-0.9%] at 5 years and 1.7% (95% CI, 1.4%-1.9%) at 10 years after transplant. The risk was significantly higher than that in the general population (SIR=1.8, 95% CI, 1.5-2.0). Risk was higher for oral cancer (SIR=15.7, 95% CI, 12.1-20.1), esophageal cancer (SIR=8.5, 95% CI, 6.1-11.5), colon cancer (SIR=1.9, 95% CI, 1.2-2.7), skin cancer (SIR=7.2, 95% CI, 3.9-12.4), and brain/nervous system cancer (SIR=4.1, 95% CI, 1.6-8.4). The risk of developing oral, esophageal, or skin cancer was higher at all times after 1-year post-transplant. Extensive-type chronic graft-versus-host disease (GVHD) was a significant risk factor for the development of all solid tumors (RR=1.8, P<0.001), as well as for oral (RR=2.9, P<0.001) and esophageal (RR=5.3, P<0.001) cancers. Limited-type chronic GVHD was an independent risk factor for skin cancers (RR=5.8, P=0.016).

CONCLUSION

Recipients of allogeneic HSCT had a significantly higher ∼2-fold risk of developing secondary solid cancers than the general population. Lifelong screening for high-risk organ sites, especially oral or esophageal cancers, is important for recipients with active, or a history of, chronic GVHD.