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We study deterministic mechanism design for constrained heterogeneous two-facility location games. The constraint here means that the feasible locations of facilities are specified and the number of facilities that can be built at each feasible location is limited. Given that a set of agents can strategically report their locations on the real line, the authority wants to design strategyproof mechanisms (i.e., mechanisms that can incentivize agents to report truthful private information) to construct two heterogeneous facilities under constraint, while optimizing the corresponding social objectives. Assuming that each agent’s individual objective depends on the sum of her distance to facilities, we consider locating desirable and obnoxious facilities respectively. For the former, we give a deterministic group strategyproof mechanism, which guarantees 3-approximation under the objectives of minimizing the sum cost and the maximum cost. We show that no deterministic strategyproof mechanism can have an approximation ratio of less than 2 under the sum/maximum cost objective. For the latter, we give a deterministic group strategyproof mechanism with 2-approximation under the objectives of maximizing the sum utility and the minimum utility. We show that no deterministic strategyproof mechanism can have an approximation ratio of less than 3/2 under the sum utility objective and 2 under the minimum utility objective, respectively. [ABSTRACT FROM AUTHOR]

Heart failure (HF) remains a global public health burden and often results following myocardial infarction (MI). Following injury, cardiac fibrosis forms in the myocardium which greatly hinders cellular function, survival, and recruitment, thus severely limits tissue regeneration. Here, we leverage biophysical microstructural cues made of hyaluronic acid (HA) loaded with the anti-fibrotic proteoglycan decorin to more robustly attenuate cardiac fibrosis after acute myocardial injury. Microrods showed decorin incorporation throughout the entirety of the hydrogel structures and exhibited first-order release kinetics in vitro. Intramyocardial injections of saline (n = 5), microrods (n = 7), decorin microrods (n = 10), and free decorin (n = 4) were performed in male rat models of ischemia-reperfusion MI to evaluate therapeutic effects on cardiac remodeling and function. Echocardiographic analysis demonstrated that rats treated with decorin microrods (5.21% ± 4.29%) exhibited significantly increased change in ejection fraction (EF) at 8 weeks post-MI compared to rats treated with saline (−4.18% ± 2.78%, p < 0.001) and free decorin (−3.42% ± 1.86%, p < 0.01). Trends in reduced end diastolic volume were also identified in decorin microrod-treated groups compared to those treated with saline, microrods, and free decorin, indicating favorable ventricular remodeling. Quantitative analysis of histology and immunofluorescence staining showed that treatment with decorin microrods reduced cardiac fibrosis (p < 0.05) and cardiomyocyte hypertrophy (p < 0.05) at 8 weeks post-MI compared to saline control. Together, this work aims to contribute important knowledge to guide rationally designed biomaterial development that may be used to successfully treat cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Submodular function has the property of diminishing marginal gain, and thus it has a wide range of applications in combinatorial optimization and in emerging disciplines such as machine learning and artificial intelligence. For any set S, most of previous works usually do not consider how to compute f(S) , but assume that there exists an oracle that will output f(S) directly. In reality, however, the process of computing the exact f is often inevitably inaccurate or costly. At this point, we adopt the easily available noise version F of f. In this paper, we investigate the problems of maximizing a non-negative monotone normalized submodular function minus a non-negative modular function under the ε -multiplicative noise in three situations, i.e., the cardinality constraint, the matroid constraint and the online unconstraint. For the above problems, we design three deterministic bicriteria approximation algorithms using greedy and threshold ideas and furthermore obtain good approximation guarantees. [ABSTRACT FROM AUTHOR]

In this paper, we propose a constrained heterogeneous facility location model where a set of alternative locations are feasible for building facilities and the number of facilities built at each feasible location is limited. Assuming that a set of agents on the real line can strategically report their locations, and the cost of each agent is her distance to the farthest one that she is interested in, we study deterministic mechanism design without money for constrained heterogeneous K-facility location games. Depending on whether agents have optional preference, the problem is considered in two settings: the compulsory setting and the optional setting. For the compulsory setting where all agents are served by K heterogeneous facilities, we provide a 3-approximate deterministic group strategyproof mechanism for the objective of minimizing the sum/maximum cost respectively, which is also the best deterministic strategyproof mechanism under the corresponding social objective. For the optional setting where each agent may be only interested in some of the facilities, we study heterogeneous two-facility location games. We propose a deterministic group strategyproof mechanism with approximation ratio of at most 2 n + 1 for the sum cost objective and a deterministic group strategyproof mechanism with approximation ratio of at most 9 for the maximum cost objective. [ABSTRACT FROM AUTHOR]

The arboricity of a graph is the minimum number of forests required to cover all its edges. In this paper, we examine arboricity from a game-theoretic perspective and investigate cost-sharing in the minimum forest cover problem. We introduce the arboricity game as a cooperative cost game defined on a graph. The players are edges, and the cost of each coalition is the arboricity of the subgraph induced by the coalition. We study properties of the core and propose an efficient algorithm for computing the nucleolus when the core is not empty. In order to compute the nucleolus in the core, we introduce the prime partition which is built on the densest subgraph lattice. The prime partition decomposes the edge set of a graph into a partially ordered set defined from minimal densest minors and their invariant precedence relation. Moreover, edges from the same partition always have the same value in a core allocation. Consequently, when the core is not empty, the prime partition significantly reduces the number of variables and constraints required in the linear programs of Maschler's scheme and allows us to compute the nucleolus in polynomial time. Besides, the prime partition provides a graph decomposition analogous to the celebrated core decomposition and the density-friendly decomposition, which may be of independent interest. [ABSTRACT FROM AUTHOR]

We consider a knapsack-constrained maximization problem of a nonnegative monotone DR-submodular function f over a bounded integer lattice [ B ] in R + n , max { f (x) : x ∈ [ B ] and ∑ i = 1 n x (i) c (i) ≤ 1 } , where n is the cardinality of a ground set N and c (·) is a cost function defined on N. Soma and Yoshida [Math. Program., 172 (2018), pp. 539-563] present a (1 - e - 1 - O (ϵ)) -approximation algorithm for this problem by combining threshold greedy algorithm with partial element enumeration technique. Although the approximation ratio is almost tight, their algorithm runs in O (n 3 ϵ 3 log 3 τ [ log 3 B ∞ + n ϵ log B ∞ log 1 ϵ c min ]) time, where c min = min i c (i) and τ is the ratio of the maximum value of f to the minimum nonzero increase in the value of f. Besides, Ene and Nguy e ˇ ~ n [arXiv:1606.08362, 2016] indirectly give a (1 - e - 1 - O (ϵ)) -approximation algorithm with O ((1 ϵ) O (1 / ϵ 4) n log ‖ B ‖ ∞ log 2 (n log ‖ B ‖ ∞)) time. But their algorithm is random. In this paper, we make full use of the DR-submodularity over a bounded integer lattice, carry forward the greedy idea in the continuous process and provide a simple deterministic rounding method so as to obtain a feasible solution of the original problem without loss of objective value. We present a deterministic algorithm and theoretically reduce its running time to a new record, O ( (1 ϵ) O (1 / ϵ 5) · n log 1 c min log ‖ B ‖ ∞) , with the same approximate ratio. [ABSTRACT FROM AUTHOR]

We study a dual-role game setting of locating facilities in a metric space where each agent can open a facility at her location or be a customer to receive the service, and an opening cost function is given to represent the cost of opening a facility at some specific location. We first show the existence of pure Nash equilibria (PNE) in such games by a polynomial-time algorithm, then use the price of anarchy (PoA) to measure the quality of PNE under social objectives of minimizing the maximum/social cost. For dual-role facility location games with general opening cost functions, we show the PoA under maximum/social cost can tend to be infinite. However, for games with L-Lipschitz conditioned opening cost functions where L ≥ 0 is a given parameter, the PoA under maximum cost is exactly L + 1 and the PoA under social cost is bounded by the interval (n + L) / 3 , n + max { L - 1 , 0 } . [ABSTRACT FROM AUTHOR]

We study a fairness-based model for 2-facility location games on the real line where the social objective is to minimize the maximum envy over all agents. All the agents seek to minimize their personal costs, and the envy between any two of them is the difference in their personal costs. We consider two cases of personal costs, called min-dist cost and sum-dist cost. We are interested in pursuing strategyproof mechanisms for 2-facility location games in both cases. For the min-dist personal cost, we first show that a lower bound of the additive approximation for any deterministic strategyproof mechanism is 1/4, then devise a deterministic group strategyproof mechanism with additive approximation of 1/2 and two randomized strategyproof mechanisms with additive approximation of 1/4. For the sum-dist personal cost, we devise a group strategyproof deterministic mechanism which is also optimal. [ABSTRACT FROM AUTHOR]

Background: Little data exist regarding interreader variability of diastolic measurements and their application by the 2016 American Society of Echocardiography left ventricular (LV) diastolic function guidelines. Methods: Volunteers (n = 49) were recruited from an outpatient cardiology practice. The presence and grade of diastology dysfunction (DD) was determined by the 2016 LV diastology guideline algorithm. We determined the mean, standard deviation, coefficient of variation, and intraclass correlation coefficient (ICC) for each measurement and Fleiss K‐statistic to define differences in grading DD. We determined predictors associated with disagreement of DD grade using odds ratios. Results: The mean LVEF was 56%, LAVI 32 ml/m2, and peak TR velocity was 2.3 m/s. The ICC for mitral inflow and tissue Doppler velocities were >.90, for LV volumes were.80–.86, and for LA volume was.56. The Fleiss K‐value for the agreement of the presence of DD was.68 and for DD grade was.59. Variables with increased odds of disagreement were (1) at least one reader considering a TR signal uninterpretable (OR 12.0; 95% CI 1.3–109.6), (2) at least one reader assessing both LVEF 50%–55% and LAVI 29–39 ml/m2 (OR 9.3; 95% CI 1.0–87), and (3) at least one reader assessing LVEF 50–55% (OR 3.8; 95% CI 1.1–13.4). Conclusions: Using the 2016 ASE/EACVI diastology guidelines, we found excellent interrater reliability of Doppler measurements, moderate‐good interrater reliability of volumetric measurements, and moderate‐good but not excellent agreement for diastology grade. [ABSTRACT FROM AUTHOR]

The matching game is a cooperative profit game defined on an edge-weighted graph, where the players are the vertices and the profit of a coalition is the maximum weight of matchings in the subgraph induced by the coalition. A population monotonic allocation scheme is a collection of rules defining how to share the profit among players in each coalition such that every player is better off when the coalition expands. In this paper, we study matching games and provide a necessary and sufficient characterization for the existence of population monotonic allocation schemes. Our characterization implies that whether a matching game admits population monotonic allocation schemes can be determined efficiently. [ABSTRACT FROM AUTHOR]

Background: Transient ischemic dilation of the left ventricle (LV) during stress echocardiography indicates extensive myocardial ischemia. It remains unclear whether the change of LV end‐systolic volume (ESV) or end‐diastolic volume (EDV) better correlated with significant coronary artery disease (CAD). Meanwhile, the clinical significance of the extent of the volumetric change post‐stress has not been investigated. Methods: One hundred and five individuals (62 ± 12 years and 75% men) who underwent coronary angiography following exercise treadmill echocardiography were enrolled retrospectively. An additional 30 age‐ and sex‐matched healthy subjects were included for comparison. LV dilation was defined as any increase in LV volume from rest to peak exercise. Patients who had at least two coronary arteries with significant stenosis were considered as having multi‐vessel CAD. Results: Thirty‐four patients had ESV dilation during exercise echocardiography. On the contrary, ESV decreased at peak exercise in all healthy subjects. Forty‐one patients had multi‐vessel CAD, and its prevalence was higher in patients with ESV dilation (65% vs 27%, p = 0.001). The extent of ESV increase correlated with CAD severity. ESV dilation is associated with multi‐vessel CAD (Odds ratio [OR] 5.02, 95% confidence interval [CI] 2.09 – 12.07, p < 0.001). After adjustment for EDV increase, clinical, electrocardiographic, and echocardiographic variables, the association remained significant (adjusted OR 5.57, 95% CI 1.37‐22.64; p = 0.02). Conclusions: ESV dilation independently correlated with multi‐vessel CAD, whereas EDV dilation did not. The amount of ESV increase correlated with the severity of CAD. Our findings provide a rationale for incorporating volume measurements into stress echocardiography practice. [ABSTRACT FROM AUTHOR]

Independent set games are cooperative games defined on graphs, where players are edges and the value of a coalition is the maximum size of independent sets in the subgraph defined by the coalition. In this paper, we study population monotonic allocation schemes for independent set games. For independent set games introduced by Deng et al. [X. Deng, T. Ibaraki and H. Nagamochi (1999). Algorithmic aspects of the core of combinatorial optimization games. Mathematics of Operations Research, 24(3), 751–766], we provide a combinatorial characterization for population monotonic allocation schemes in convex instances. For independent set games introduced by Xiao et al. [H. Xiao, Y. Wang and Q. Fang (2021). On the convexity of independent set games. Discrete Applied Mathematics, 291, 271–276], we prove the equivalence of convexity, population monotonicity and balancedness. [ABSTRACT FROM AUTHOR]

Selfish bin packing can be viewed as the non-cooperative version of bin packing problem, where every item is a selfish agent and wants to minimize his sharing cost with the other items packing in the same bin. In this paper, we focus on designing a new mechanism (a payoff rule) for selfish bin packing, called modified Dutch treatment mechanism. We first show that the pure Nash equilibrium exists and it can be obtained in polynomial time. We then prove that under the new mechanism, the price of anarchy is between 1.47407 and 1.4748, improving the known results. [ABSTRACT FROM AUTHOR]

Intramyocardial injection of hydrogels offers great potential for treating myocardial infarction (MI) in a minimally invasive manner. However, traditional bulk hydrogels generally lack microporous structures to support rapid tissue ingrowth and biochemical signals to prevent fibrotic remodeling toward heart failure. To address such challenges, a novel drug‐releasing microporous annealed particle (drugMAP) system is developed by encapsulating hydrophobic drug‐loaded nanoparticles into microgel building blocks via microfluidic manufacturing. By modulating nanoparticle hydrophilicity and pregel solution viscosity, drugMAP building blocks are generated with consistent and homogeneous encapsulation of nanoparticles. In addition, the complementary effects of forskolin (F) and Repsox (R) on the functional modulations of cardiomyocytes, fibroblasts, and endothelial cells in vitro are demonstrated. After that, both hydrophobic drugs (F and R) are loaded into drugMAP to generate FR/drugMAP for MI therapy in a rat model. The intramyocardial injection of MAP gel improves left ventricular functions, which are further enhanced by FR/drugMAP treatment with increased angiogenesis and reduced fibrosis and inflammatory response. This drugMAP platform represents a new generation of microgel particles for MI therapy and will have broad applications in regenerative medicine and disease therapy. [ABSTRACT FROM AUTHOR]

Introduction: Cardiac adaptation to sustained exercise in the athletes is established. However, exercise‐associated effect on the cardiac function of the elderly has to be elucidated. The aim of this study was to analyse left (LV) and right ventricular (RV) characteristics at different levels of chronic exercise in the senior heart. Materials and methods: We studied 178 participants in the World Senior Games (mean age 68 ± 8 years, 86 were men; 48%). Three groups were defined based on the type and intensity of sports: low‐, moderate‐ and high‐intensity level. Exclusion criteria were coronary artery disease, atrial fibrillation, valvular heart disease or uncontrolled hypertension. LV and RV size and function were evaluated with an echocardiogram. Results: LV trans‐mitral inflow deceleration time decreased in parallel to the intensity of chronic exercise: 242 ± 54 ms in low‐, 221 ± 52 ms in moderate‐ and 215 ± 58 ms in high‐intensity level, p =.03. Left atrial volume index (LAVI) was larger in high‐intensity group, p =.001. The LAVI remained significantly larger when adjusting for age, gender, heart rate, hypertension and diabetes (p =.002). LV and RV sizes were larger in the high‐intensity group. LV ejection fraction and RV systolic function evaluated by tissue Doppler velocity, atrioventricular plane displacement and strain did not differ between groups. Conclusion: Left ventricular diastolic filling is not only preserved, but may also be enhanced in long‐term, top‐level senior athletes. Moreover, LV and RV systolic function remain unchanged at different levels of exercise. This supports the beneficial effects of endurance exercise participation in senior hearts. [ABSTRACT FROM AUTHOR]

Aims: We report the collective European experience of percutaneous left atrial appendage (LAA) suture ligation using the recent generation LARIAT+ suture delivery device.Methods and Results: A total of 141 patients with non-valvular atrial fibrillation and contraindication to oral anticoagulation (OAC), thrombo-embolic events despite OAC or electrical LAA isolation were enrolled at seven European hospitals to undergo LAA ligation. Patients were followed up by clinical visits and transoesophageal echocardiography (TOE) following LAA closure. Left atrial appendage ligation was completed in 138/141 patients (97.8%). Three patients did not undergo attempted deployment of the LARIAT device due to pericardial adhesion after previous epicardial ventricular tachycardia ablation (n = 1), a pericardial access-related complication (n = 1), and multiple posterior LAA lobes (n = 1). Serious 30-day procedural adverse events occurred in 4/141 patients (2.8%). There were two device-related LAA perforations (1.4%) not resulting in any corrective intervention as the LAA was completely sealed with the LARIAT. Minor adverse events occurred in 19 patients (13.5%), including two pericardial effusions due to procedure-related pericarditis requiring pericardiocentesis. Transoesophageal echocardiography was performed after LAA ligation in 103/138 patients (74.6%) after a mean of 181 ± 72 days. Complete LAA closure was documented in 100 patients (97.1%). Two patients (1.8% of patients with follow-up) experienced a transient ischaemic attack at 4 and 7 months follow-up, although there was no leak observed with TOE. There were two deaths during long-term follow-up which were both not device related.Conclusion: Initial experience with the LARIAT+ device demonstrates feasibility of LAA exclusion. Further larger prospective studies with longer follow-up are warranted. [ABSTRACT FROM AUTHOR]

Background: Serial increases in high-sensitivity cardiac troponin (hs-cTnT) have been associated with death in community-dwelling adults, but the association remains uninvestigated in those with coronary artery disease (CAD). Methods: We measured hs-cTnT at baseline and after 5 years in 635 ambulatory Heart and Soul Study patients with CAD. We also performed echocardiography at rest and after treadmill exercise at baseline and after 5 years. Participants were subsequently followed for the outcome of death. We used a multivariable-adjusted Cox proportional hazards model to evaluate the association between 5-year change in hs-cTnT and subsequent all-cause mortality. Results: Of the 635 subjects, there were 386 participants (61%) who had an increase in hs-cTnT levels between baseline and year 5 measurements (median increase 5.6 pg/mL, IQR 3.2–9.9 pg/mL). There were 182 deaths after a mean 4.2-year follow-up after the year 5 visit. After adjusting for clinical variables, a >50% increase in hs-cTnT between baseline and year 5 was associated with a nearly 2-fold increased risk of death from any cause (hazard ratio 1.7, 95% confidence interval 1.1–2.7). When addition of year 5 hs-cTnT was compared to a model including clinical variables and baseline hs-cTnT, there was a modest but statistically significant increase in C-statistic from 0.82 to 0.83 (p = 0.04). Conclusion: In ambulatory patients with CAD, serial increases in hs-cTnT over time are associated with an increased risk of death. [ABSTRACT FROM AUTHOR]

We study the problem of maximizing an increasing function f : 2 N → R + subject to matroid constraints. Gruia Calinescu, Chandra Chekuri, Martin Pál and Jan Vondrák have shown that, if f is nondecreasing and submodular, the continuous greedy algorithm and pipage rounding technique can be combined to find a solution with value at least 1 - 1 / e of the optimal value. But pipage rounding technique have strong requirement for submodularity. Chandra Chekuri, Jan Vondrák and Rico Zenklusen proposed a rounding technique called contention resolution schemes. They showed that if f is submodular, the objective value of the integral solution rounding by the contention resolution schemes is at least 1 - 1 / e times of the value of the fractional solution. Let f : 2 N → R + be an increasing function with generic submodularity ratio γ ∈ (0 , 1 ] , and let (N , I) be a matroid. In this paper, we consider the problem max S ∈ I f (S) and provide a γ (1 - e - 1) (1 - e - γ - o (1)) -approximation algorithm. Our main tools are the continuous greedy algorithm and contention resolution schemes which are the first time applied to nonsubmodular functions. [ABSTRACT FROM AUTHOR]

Objective: Bileaflet mitral valve prolapse (MVP) with either focal or diffuse myocardial fibrosis has been linked to ventricular arrhythmia and/or sudden cardiac arrest. Left ventricular (LV) mechanical dispersion by speckle-tracking echocardiography (STE) is a measure of heterogeneity of ventricular contraction previously associated with myocardial fibrosis. The aim of this study is to determine whether mechanical dispersion can identify MVP at higher arrhythmic risk.Methods: We identified 32 consecutive arrhythmic MVPs (A-MVP) with a history of complex ventricular ectopy on Holter/event monitor (n=23) or defibrillator placement (n=9) along with 27 MVPs without arrhythmic complications (NA-MVP) and 39 controls. STE was performed to calculate global longitudinal strain (GLS) as the average peak longitudinal strain from an 18-segment LV model and mechanical dispersion as the SD of the time to peak strain of each segment.Results: MVPs had significantly higher mechanical dispersion compared with controls (52 vs 42 ms, p=0.005) despite similar LV ejection fraction (62% vs 63%, p=0.42) and GLS (-19.7 vs -21, p=0.045). A-MVP and NA-MVP had similar demographics, LV ejection fraction and GLS (all p>0.05). A-MVP had more bileaflet prolapse (69% vs 44%, p=0.031) with a similar degree of mitral regurgitation (mostly trace or mild in both groups) (p>0.05). A-MVP exhibited greater mechanical dispersion when compared with NA-MVP (59 vs 43 ms, p=0.0002). Mechanical dispersion was the only significant predictor of arrhythmic risk on multivariate analysis (OR 1.1, 95% CI 1.02 to 1.11, p=0.006).Conclusions: STE-derived mechanical dispersion may help identify MVP patients at higher arrhythmic risk. [ABSTRACT FROM AUTHOR]

Information propagation plays an important role in social network, which helps shaping consumer's purchasing decisions. Most of existing works focus on maximizing the influence of one product. But in our reality life, the majority of the companies produce various products for meeting customer needs. So it is important to learn about how to distribute the limited budget to maximize the companies profits. In this paper, we use the martingale technique to handle the Profit Maximization with Multiple Adoptions ( P M 2 A ) problem, which aims to identify a seed set for each product with overall activation cost at most B such that the expected total profit is maximized. We design a P M 2 A M algorithm which returns a (1 2 (1 - 1 e 2) - ε) -approximate solution and runs in O (k ∗ + ℓ) (m + n) n q p max ln n q / (ε 2 · p min) expected time. [ABSTRACT FROM AUTHOR]

Introduction: Although systolic and diastolic dysfunction must coexist, they are most often considered in isolation. Therefore, a simple and reproducible quantitative measurement that integrates systolic and diastolic function is desirable. We hypothesize that the absolute sum of lateral mitral annular systolic and early diastolic peak velocities is predictive of overall cardiac function. Methods: In this study, lateral mitral annular systolic (S′) and early diastolic (E′) peak velocities were measured in healthy subjects and compared against subjects with progressive degrees of systolic and diastolic dysfunction. Results: A total of 149 subjects (56% male, mean age 48 years) were enrolled and stratified according to global left ventricular function: 76 normal, 40 mild‐moderate dysfunction, and 33 moderate‐severe dysfunction. Adjusting for baseline differences including age, univariate analysis showed mean S′ + E′ values were significantly different between subjects with normal, mild‐moderate, and moderate‐severe global left ventricular function (27, 17, 13 cm/s; P < 0.001 for all comparisons). The absolute sum of S′ + E′ ≥ 20 cm/s identified normal global left ventricular function with a sensitivity of 95%, specificity of 85%, and ROC area under the curve of 0.924. Conclusions: In a cohort of subjects with varying levels of combined systolic and diastolic function, the easily obtainable composite score of S′ + E′ ≥ 20 cm/s is strongly predictive of normal global left ventricular function with a high degree of sensitivity and specificity. Additional studies should be considered to expand this concept to additional populations. [ABSTRACT FROM AUTHOR]

Cooperative games provide an appropriate framework for fair and stable profit distribution in multiagent systems. In this paper, we study the algorithmic issues on path cooperative games that arise from the situations where some commodity flows through a network. In these games, a coalition of edges or vertices is successful if they establish a path from the source to the sink in the network, and lose otherwise. Based on dual theory of linear programming and the relationship with flow games, we provide the characterizations on the core, CS-core, least-core and nucleolus of path cooperative games, which implies all of these solution concepts are polynomial-time solvable for path cooperative games. [ABSTRACT FROM AUTHOR]

This paper consists of two parts. In the first part, we study a centralized rumor blocking problem with a novel social objective function different from those in the literature. We will show that this objective function is non-decreasing and submodular and hence corresponding rumor blocking problem has a greedy approximation with objective function value at least $$1-1/e$$ of the optimal. In the second part, we study a decentralized rumor blocking problem with two selfish protectors, which falls into a 2-player non-cooperate game model. We will show that this game is a basic valid utility system and hence the social utility of any Nash equilibrium in the game is at least a half of the optimal social utility. [ABSTRACT FROM AUTHOR]

To further define the age‐related distribution of diastolic function as defined by E/A ratio, in healthy male adults. The age‐sensitive ratio of mitral inflow E‐wave to A‐wave (E/A) velocity is often considered in the evaluation of diastolic function. To appropriately direct a comprehensive evaluation of diastolic function, we sought to improve the characterization of the influence of age on E/A ratio. We analyzed echocardiographic data from the Mind Your heart Study, a cohort of outpatients recruited from two San Francisco Veterans centers to examine the effect of mental health on cardiovascular outcomes. Individuals with a history of heart disease or hypertension were excluded, leaving 313 veterans for analysis. We examined E/A by 5‐year increments and performed linear and logistic regression analysis to predict trends in E/A and E dominance. Within the age ranges of population (54.9 ± 11.5), there is a steady gradual decline in absolute E/A ratio (beta coefficient/year‐ 0.018, P < .001) and the odds of E dominance similarly declines with age (odds ratio/year = 0.89, P < .001). Despite this decline, 90% of individuals below the age of 50 years maintain E dominance. Beyond age 50, 55% maintain E dominance, and beyond age 70, only 28% have E dominance. In this adequately healthy population, age‐related progression of delayed relaxation appears to be a state of normality rather than diastolic dysfunction. Careful attention to specific cutoff points in age and E/A ratio could avoid misinterpretation or inappropriate management. [ABSTRACT FROM AUTHOR]

Despite the controversy in mechanism, rodent and clinical studies have demonstrated beneficial effects of stem/progenitor cell therapy after myocardial infarction ( MI). In a rat ischaemic reperfusion MI model, we investigated the effects of immunomodification of CD 34+ cells on heart function and myocardial conduction. Bispecific antibody (BiAb), consisting of an anti-myosin light chain antibody and anti- CD45 antibody, injected intravenously was used to direct human CD34+ cells to injured myocardium. Results were compared to echocardiography guided intramyocardial ( IM) injection of CD34+ cells and PBS injected intravenously. Treatment was administered 2 days post MI. Echocardiography was performed at 5 weeks and 3 months which demonstrated LV dilatation prevention and fractional shortening improvement in both the BiAb and IM injection approaches, with BiAb achieving better results. Histological analyses demonstrated a decrease in infarct size and increase in arteriogenesis in both BiAb and IM injection. Electrophysiological properties were studied 5 weeks after treatments by optical mapping. Conduction velocity ( CV), action potential duration ( APD) and rise time were significantly altered in the MI area. The BiAb treated group demonstrated a more normalized activation pattern of conduction and normalization of CV at shorter pacing cycle lengths. The ventricular tachycardia inducibility was lowest in the BiAb treatment group. Intravenous administration of BiAb offers an effective means of stem cell delivery for myocardial repair post-acute MI. Such non-invasive approach was shown to offer a distinct advantage to more invasive direct IM delivery. [ABSTRACT FROM AUTHOR]

Background Aging is associated with higher incidence of heart failure and death following myocardial infarction ( MI). The molecular and cellular changes that lead to these worse outcomes are not known. Methods and Results Young and aging mice underwent induction of MI by LAD ligation. There was a significant increase in mortality in the aging mice. Neither the young nor aging hearts after MI had inducible ventricular tachycardia. Cardiomyocyte apoptosis increases early after MI in young and aging mice, but to a much greater degree in the aging mice. Caspase inhibition with Ac- DEVD- CHO resulted in a 61% reduction in activated caspase-3 and an 84% reduction in apoptosis in cardiomyocytes in young mice ( P < 0.05), but not in aging mice. Gene pathway profiling demonstrated activation of both the caspase and Map3k1/ Mapk10 pathways in aging mice following MI, which may contribute to their resistance to caspase inhibition. Conclusions Aging hearts activate distinct apoptotic pathways have more cardiomyocyte apoptosis and are resistant to antiapoptotic therapies following MI. Novel or combination approaches may be required to improve outcomes in aging patients following MI. [ABSTRACT FROM AUTHOR]

Pleiotrophin (PTN) is a growth factor with both pro-angiogenic and limited pro-tumorigenic activity. We evaluated the potential for PTN to be used for safe angiogenic gene therapy using the full length gene and a truncated gene variant lacking the domain implicated in tumorigenesis. Mouse myoblasts were transduced to express full length or truncated PTN (PTN or T-PTN), along with a LacZ reporter gene, and injected into mouse limb muscle and myocardium. In cultured myoblasts, PTN was expressed and secreted via the Golgi apparatus, but T-PTN was not properly secreted. Nonetheless, no evidence of uncontrolled growth was observed in cells expressing either form of PTN. PTN gene delivery to myocardium, and non-ischemic skeletal muscle, did not result in a detectable change in vascularity or function. In ischemic hindlimb at 14 days post-implantation, intramuscular injection with PTN-expressing myoblasts led to a significant increase in skin perfusion and muscle arteriole density. We conclude that (1) delivery of the full length PTN gene to muscle can be accomplished without tumorigenesis, (2) the truncated PTN gene may be difficult to use in a gene therapy context due to inefficient secretion, (3) PTN gene delivery leads to functional benefit in the mouse acute ischemic hindlimb model. [ABSTRACT FROM AUTHOR]

Purpose: Semi-quantitative, static positron emission tomography (PET) has been used to perform an initial approach to the assessment of [13N]-ammonia perfusion studies aimed to elucidating the effect of injecting human embryonic stem cell-derived (hES) hemangioblasts on infarcted rat hearts. Procedures: Female NIH nude rats underwent occlusion of the left anterior descending coronary artery for 30 min before reperfusion. Either one million hES-derived hemangioblasts ( n = 5) or control media ( n = 4) were injected into the site of the infarct 1 day post-myocardial infarction (MI) under high-resolution echocardiography guidance. PET imaging was performed 6 weeks after MI induction, and uptake polar maps were created by sampling the left ventricle at equidistant slices from the base to the apex and measuring the average myocardium value at three contiguous voxels to minimize partial volume effects. Statistical comparison between treatment and control groups was done with a Mann-Whitney U test. Results: Myocardium uptake ratios for treated and untreated subjects show statistically significant difference (98% certainty). Conclusions: The straightforward procedure described here (similar to those commonly used in clinical routine) was sufficient to yield statistically significant perfusion differences between the treated and untreated animals despite the small sample size. [ABSTRACT FROM AUTHOR]

We study core stability and some related properties of flow games defined on simple networks (all edge capacities are equal) from an algorithmic point of view. We first present a sufficient and necessary condition that can be tested efficiently for a simple flow game to have a stable core. We also prove the equivalence of the properties of core largeness, extendability, and exactness of simple flow games and provide an equivalent graph theoretic characterization which allows us to decide these properties in polynomial time. [ABSTRACT FROM AUTHOR]

Hematopoietic stem cell (HSC) therapy for myocardial repair is limited by the number of stem cells that migrate to, engraft in, and proliferate at sites of injured myocardium. To alleviate this limitation, we studied whether a strategy using a bispecific antibody (BiAb) could target human stem cells specifically to injured myocardium and preserve myocardial function. Using a xenogeneic rat model whereby ischemic injury was induced by transient ligation of the left anterior descending artery (LAD), we determined the ability of a bispecific antibody to target human CD34+ cells to specific antigens expressed in ischemic injured myocardium. A bispecific antibody comprising an anti-CD45 antibody recognizing the common leukocyte antigen found on HSCs and an antibody recognizing myosin light chain, an organ-specific injury antigen expressed by infarcted myocardium, was prepared by chemical conjugation. CD34+ cells armed and unarmed with this BiAb were injected intravenously in rats 2 days postmyocardial injury. Immunohistochemistry studies showed that the armed CD34+ cells specifically localized to the infarcted region of the heart, colocalized with troponin T-stained cells, and colocalization with vascular structures. Compared to unarmed CD34+ cells, the bispecific antibody improved delivery of the stem cells to injured myocardium, and such targeted delivery was correlated with improved myocardial function 5 weeks after infarction (p < .01). Bispecific antibody targeting offers a unique means to improve the delivery of stem cells to facilitate organ repair and a tool to study stem cell biology. [ABSTRACT FROM AUTHOR]

In this work, we consider a public facility allocation problem decided through a voting process under the majority rule. A location of the public facility is a majority rule winner if there is no other location in the network where more than half of the voters would have been closer to than the majority rule winner. We develop fast algorithms for interesting cases with nice combinatorial structures. We show that the computing problem and the decision problem in the general case, where the number of public facilities is more than one and is considered part of the input size, are all NP-hard. Finally, we discuss majority rule decision making for related models. [ABSTRACT FROM AUTHOR]

Social choice theory is the study of decision theory on how to aggregate separate preferences into group's rational preference. It has wide applications, especially on the design of voting rules, and brings far-reaching influence on the development of modern political science and welfare economics. With the advent of the information age, social choice theory finds its up-to-date application on designing effective Metasearch engines. Metasearch engines provide effective searching by combining the results of multiple source search engines that make use of diverse models and techniques. In this work, we analyze social choice algorithms in a graph-theoretic approach. In addition to classical social choice algorithms, such as Borda and Condorcet, we study one special type of social choice algorithms, elimination voting, to tackle Metasearch problem. Some new algorithms are proposed and examined in the fusion experiment on TREC data. It shows that these elimination voting algorithms achieve satisfied performance when compared with Borda algorithm. [ABSTRACT FROM AUTHOR]

Let Γ = (N, v) be a cooperative game with the player set N and value function v : 2[supN] → R. A solution of the game is in the core if no subset of players could gain advantage by breaking away from the grand coalition of all players. This paper surveys theoretical results on the cores for some cooperative game models. These results proved that the linear program duality characterization of the core is a very powerful tool. We will focus on linear and integer programming techniques applied in this area. [ABSTRACT FROM AUTHOR]

Let г ≡ (N, ν) be a cooperative game with the player set N and characteristic function ν: 2[SUPN] → R. An imputation of the game is in the core if no subset of players could gain advantage by splitting from the grand coalition of all players. It is well known that, for the flow game (and equivalently, for the linear production game), the core is always non-empty and a solution in the core can be found in polynomial time. In this paper, we show that, given an imputation x, it is NP-complete to decide x is nota member of the core, for the flow game. And because of the specific reduction we constructed, the result also holds for the linear production game. [ABSTRACT FROM AUTHOR]