Strategyproof matching with regional minimum and maximum quotas

This paper considers matching problems with individual/regional minimum/maximum quotas. Although such quotas are relevant in many real-world settings, there is a lack of strategyproof mechanisms that take such quotas into account. We first show that without any restrictions on the regional structure, checking the existence of a feasible matching that satisfies all quotas is NP-complete. Then, assuming that regions have a hierarchical structure (i.e., a tree), we show that checking the existence of a feasible matching can be done in time linear in the number of regions. We develop two strategyproof matching mechanisms based on the Deferred Acceptance mechanism (DA), which we call Priority List based Deferred Acceptance with Regional minimum and maximum Quotas (PLDA-RQ) and Round-robin Selection Deferred Acceptance with Regional minimum and maximum Quotas (RSDA-RQ). When regional quotas are imposed, a stable matching may no longer exist since fairness and nonwastefulness, which compose stability, are incompatible. We show that both mechanisms are fair. As a result, they are inevitably wasteful. We show that the two mechanisms satisfy different versions of nonwastefulness respectively; each is weaker than the original nonwastefulness. Moreover, we compare our mechanisms with an artificial cap mechanism via simulation experiments, which illustrate that they have a clear advantage in terms of nonwastefulness and student welfare

Regulation of dynamic structure of cyclophanes by their complexation with the porphyrin

Dithia[3.3]metacyclophanes which consist of the pyridine unit connecting to the different positions of the parent cyclophane skeleton have been prepared. Conformational change has been observed for the cyclophane having a 4-substituted pyridine unit by binding to the porphyrin. In contrast the porphyrin binding has no influence on conformational behavior of the cyclophane having a 3-substituted pyridine unit

Regulation of dynamic structure of cyclophanes by their complexation with the porphyrin

Dithia[3.3]metacyclophanes which consist of the pyridine unit connecting to the different positions of the parent cyclophane skeleton have been prepared. Conformational change has been observed for the cyclophane having a 4-substituted pyridine unit by binding to the porphyrin. In contrast the porphyrin binding has no influence on conformational behavior of the cyclophane having a 3-substituted pyridine unit

Improving Fairness and Efficiency in Matching with Distributional Constraints: An Alternative Solution for the Japanese Medical Residency Match

Regional imbalance of doctors is a serious issue in many countries. In an attempt to average the geographical distribution of doctors, the Japanese government introduced ``regional caps'' recently, restricting the total number of medical residents matched within each region. Motivated by this policy change, Kamada and Kojima (2013) proposed a mechanism called the flexible deferred acceptance mechanism (FDA) that makes every doctor weakly better off than the current system. In this paper, we further study this problem and develop an alternative mechanism that we call the priority-list based deferred acceptance mechanism (PLDA). Both mechanisms enable hospitals in the same region to fill their capacities flexibly until the regional cap is filled. FDA lets hospitals take turns to (tentatively) choose the best remaining doctor, while PLDA lets each region directly decide which doctor is (tentatively) matched with which hospital based on its priority list. We show that PLDA performs better than FDA in terms of efficiency and fairness through theoretical and computational analyses

Improving Fairness and Efficiency in Matching with Distributional Constraints: An Alternative Solution for the Japanese Medical Residency Match

Regional imbalance of doctors is a serious issue in many countries. In an attempt to average the geographical distribution of doctors, the Japanese government introduced ``regional caps'' recently, restricting the total number of medical residents matched within each region. Motivated by this policy change, Kamada and Kojima (2013) proposed a mechanism called the flexible deferred acceptance mechanism (FDA) that makes every doctor weakly better off than the current system. In this paper, we further study this problem and develop an alternative mechanism that we call the priority-list based deferred acceptance mechanism (PLDA). Both mechanisms enable hospitals in the same region to fill their capacities flexibly until the regional cap is filled. FDA lets hospitals take turns to (tentatively) choose the best remaining doctor, while PLDA lets each region directly decide which doctor is (tentatively) matched with which hospital based on its priority list. We show that PLDA performs better than FDA in terms of efficiency and fairness through theoretical and computational analyses

Designing Matching Mechanisms under General Distributional Constraints

In this paper, we consider two-sided, many-to-one matching problems where agents in one side of the market (schools) impose some distributional constraints (e.g., a maximum quota for a set of schools), and develop a strategyproof mechanism that can handle a very general class of distributional constraints. We assume distributional constraints are imposed on a vector, where each element is the number of contracts accepted for each school. The only requirement we impose on distributional constraints is that the family of vectors that satisfy distributional constraints must be hereditary, which means if a vector satisfies the constraints, any vector that is smaller than it also satisfies them. When distributional constraints are imposed, a stable matching may not exist. We develop a strategyproof mechanism called Adaptive Deferred Acceptance mechanism (ADA), which is nonwasteful and ``more fair'' than a simple nonwasteful mechanism called the Serial Dictatorship mechanism (SD) and ``less wasteful'' than another simple fair mechanism called the Artificial Cap Deferred Acceptance mechanism (ACDA). We show that we can apply this mechanism even if the distributional constraints do not satisfy the hereditary condition by applying a simple trick, assuming we can find a vector that satisfy the distributional constraints efficiently. Furthermore, we demonstrate the applicability of our model in actual application domains

Designing Matching Mechanisms under General Distributional Constraints

In this paper, we consider two-sided, many-to-one matching problems where agents in one side of the market (schools) impose some distributional constraints (e.g., a maximum quota for a set of schools), and develop a strategyproof mechanism that can handle a very general class of distributional constraints. We assume distributional constraints are imposed on a vector, where each element is the number of contracts accepted for each school. The only requirement we impose on distributional constraints is that the family of vectors that satisfy distributional constraints must be hereditary, which means if a vector satisfies the constraints, any vector that is smaller than it also satisfies them. When distributional constraints are imposed, a stable matching may not exist. We develop a strategyproof mechanism called Adaptive Deferred Acceptance mechanism (ADA), which is nonwasteful and ``more fair'' than a simple nonwasteful mechanism called the Serial Dictatorship mechanism (SD) and ``less wasteful'' than another simple fair mechanism called the Artificial Cap Deferred Acceptance mechanism (ACDA). We show that we can apply this mechanism even if the distributional constraints do not satisfy the hereditary condition by applying a simple trick, assuming we can find a vector that satisfy the distributional constraints efficiently. Furthermore, we demonstrate the applicability of our model in actual application domains

Clinical relevance and functional significance of cell-free microRNA-1260b expression profiles in infiltrative myxofibrosarcoma

Infiltrative tumor growth into adjacent soft tissues is a major cause of the frequent recurrence and tumor-related death of myxofibrosarcoma (MFS), but no useful biomarkers reflecting tumor burden and infiltrative growth are available. While emerging evidence suggests a diagnostic and functional role of extracellular/circulating microRNA (miRNA) in various malignant diseases, their significance in MFS patients remains unknown. Global miRNA profiling identified four upregulated miRNAs in MFS patient sera and culture media of MFS cells. Among these, serum miR-1260b level was significantly upregulated in patient serum discriminating from healthy individuals and closely correlated with clinical status and tumor dynamics in MFS-bearing mice. In addition, high miR-1260b expression in serum was correlated with radiological tail-like patterns, characteristic of the infiltrative MFS. The extracellular miR-1260b was embedded in tumor-derived extracellular vesicles (EVs) and promoted cellular invasion of MFS through the downregulation of PCDH9 in the adjacent normal fibroblasts. Collectively, circulating miR-1260b expression may represent a novel diagnostic target for tumor monitoring of this highly aggressive sarcoma. Moreover, EV-miR-1260b could act as a transfer messenger to adjacent cells and mediate the infiltrative growth of MFS, providing new insights into the mechanism of infiltrative nature via crosstalk between tumor cells and their microenvironment

Clinical and Functional Significance of Intracellular and Extracellular microRNA-25-3p in Osteosarcoma

Although there is considerable evidence indicating that the dysregulation of microRNAs (miRNAs) in malignant tumors plays a role in tumor development, the overall function of miRNAs and their clinicopathological significance are not well understood. In this retrospective analysis of 45 biopsy specimens from osteosarcoma (OS) patients, we investigated the functional and clinical significance of miR-25-3p in OS, which we previously identified as a highly expressed miRNA in OS patients’ serum. We observed that miR-25-3p dysregulation in human OS tissues was negatively correlated with the clinical prognosis, whereas the expression level of its target gene, Dickkopf WNT Signaling Pathway Inhibitor 3 (DKK3), was positively correlated with the clinical prognosis. Endogenous miR-25-3p upregulation promoted tumor growth, invasion, and drug resistance, which was consistent with DKK3 silencing in OS cells. In addition, secretory miR-25-3p was embedded in tumor-derived exosomes, where it promoted capillary formation and the invasion of vascular endothelial cells. Overall, our results show that miR-25-3p has intracellular and extracellular oncogenic functions as well as clinicopathological relevance in OS, indicating its potential as a novel diagnostic and therapeutic tool for the clinical management of this disease