Strangeness-driven Exploration in Multi-Agent Reinforcement Learning

Efficient exploration strategy is one of essential issues in cooperative multi-agent reinforcement learning (MARL) algorithms requiring complex coordination. In this study, we introduce a new exploration method with the strangeness that can be easily incorporated into any centralized training and decentralized execution (CTDE)-based MARL algorithms. The strangeness refers to the degree of unfamiliarity of the observations that an agent visits. In order to give the observation strangeness a global perspective, it is also augmented with the the degree of unfamiliarity of the visited entire state. The exploration bonus is obtained from the strangeness and the proposed exploration method is not much affected by stochastic transitions commonly observed in MARL tasks. To prevent a high exploration bonus from making the MARL training insensitive to extrinsic rewards, we also propose a separate action-value function trained by both extrinsic reward and exploration bonus, on which a behavioral policy to generate transitions is designed based. It makes the CTDE-based MARL algorithms more stable when they are used with an exploration method. Through a comparative evaluation in didactic examples and the StarCraft Multi-Agent Challenge, we show that the proposed exploration method achieves significant performance improvement in the CTDE-based MARL algorithms.Comment: 9 pages, 7 figure

ArrayXPath II: mapping and visualizing microarray gene-expression data with biomedical ontologies and integrated biological pathway resources using Scalable Vector Graphics

Summary: ArrayXPath () is a web-based service for mapping and visualizing microarray gene-expression data with integrated biological pathway resources using Scalable Vector Graphics (SVG). Deciphering the crosstalk among pathways and integrating biomedical ontologies and knowledge bases may help biological interpretation of microarray data. ArrayXPath is empowered by integrating gene-pathway, disease-pathway, drug-pathway and pathway–pathway correlations with integrated Gene Ontology, Medical Subject Headings and OMIM Morbid Map-based annotations. We applied Fisher's exact test and relative risk to evaluate the statistical significance of the correlations. ArrayXPath produces Javascript-enabled SVGs for web-enabled interactive visualization of gene-expression profiles integrated with gene-pathway-disease interactions enriched by biomedical ontologies

Bocavirus Infection in Hospitalized Children, South Korea

This study presents the first evidence of human bocavirus infection in South Korean children. The virus was detected in 27 (8.0%) of 336 tested specimens, including 17 (7.5%) of 225 virus-negative specimens, collected from children with acute lower respiratory tract infection

GIS-NaP1 zeolite microspheres as potential water adsorption material: Influence of initial silica concentration on adsorptive and physical/topological properties

GIS-NaP1 zeolite samples were synthesized using seven different Si/Al ratios (5–11) of the hydrothermal reaction mixtures having chemical composition Al2O3:xSiO2:14Na2O:840H2O to study the impact of Si/Al molar ratio on the water vapour adsorption potential, phase purity, morphology and crystal size of as-synthesized GIS-NaP1 zeolite crystals. The X-ray diffraction (XRD) observations reveal that Si/Al ratio does not affect the phase purity of GIS-NaP1 zeolite samples as high purity GIS-NaP1 zeolite crystals were obtained from all Si/Al ratios. Contrary, Si/Al ratios have remarkable effect on the morphology, crystal size and porosity of GIS-NaP1 zeolite microspheres. Transmission electron microscopy (TEM) evaluations of individual GIS-NaP1 zeolite microsphere demonstrate the characteristic changes in the packaging/arrangement, shape and size of primary nano crystallites. Textural characterisation using water vapour adsorption/desorption, and nitrogen adsorption/desorption data of as-synthesized GIS-NaP1 zeolite predicts the existence of mix-pores i.e., microporous as well as mesoporous character. High water storage capacity 1727.5 cm3 g−1 (138.9 wt.%) has been found for as-synthesized GIS-NaP1 zeolite microsphere samples during water vapour adsorption studies. Further, the total water adsorption capacity values for P6 (1299.4 mg g−1) and P7 (1388.8 mg g−1) samples reveal that these two particular samples can absorb even more water than their own weights

Long COVID in children and adolescents: prevalence, clinical manifestations, and management strategies

Long coronavirus disease (COVID), also known as postacute sequelae of severe acute respiratory syndrome coronavirus 2 infection, has been defined as signs and symptoms which persist for 4 weeks or even lasting for 6 months after the initial infection. Although the prevalence of long COVID in children is currently unknown, epidemiological investigations have reported cases in pediatric populations. Clinical manifestations of long COVID in children include respiratory symptoms, such as cough and dyspnea, as well as neuropsychiatric and general conditions, including fatigue, headache, and muscle weakness. The pathophysiology of long COVID in children is still being investigated, but potential mechanisms include viral persistence, autoimmunity, and neuroinflammation. Risk factors for long COVID in children are not yet well understood, but studies have suggested that children with a history of severe acute COVID-19 infection or comorbidities may be at increased risk. Evaluation for respiratory symptoms of long COVID in children is essential, including spirometry and imaging studies to assess lung function and any potential damage. Furthermore, long COVID in children has been associated with a higher prevalence of mental health problems than in adults, emphasizing the importance of monitoring and addressing these aspects in pediatric patients. Although our understanding of long COVID in children and adolescents is still evolving, it is clear that the condition can have significant impacts on their health and well-being. The aim of this review is to synthesize the current knowledge on the prevalence, risk factors, and pathophysiology of long COVID in children and adolescents, and to discuss potential management strategies based on existing evidence

Prevalence of human parechovirus and enterovirus in cerebrospinal fluid samples in children in Jinju, Korea

PurposeHuman parechovirus (HPeV) and enterovirus (EV) are causative agents of a sepsis-like illness in neonates and of infections of the central nervous system in young children. The objectives of this study were to assess the prevalence of HPeV3 and EV infection in young children with a sepsis-like illness or with meningitis in Jinju, Korea.MethodsCerebrospinal fluid (CSF) samples were collected from 267 patients (age range, 1 day to 5 years) and assessed for HPeV and EV by performing reverse transcription polymerase chain reaction assay. Amplification products of the VP3/VP1 region of HPeV and of the VP1 region of EV were sequenced to identify the virus type.ResultsHPeV and EV were detected in 3.4% and 7.5% of the total CSF samples assessed, respectively. The age distribution of EV-positive patients (median age, 1.4 months) had a significantly broader range than that of HPeV-positive patients (median age, 7.8 months). The peak seasons for HPeV and EV infection were spring and summer, respectively. The clinical symptoms for HPeV and EV infection were similar, and fever was the most common symptom. Pleocytosis was detected in 22.2% of HPeV-positive patients and 35.5% of EV-positive patients. The VP3/VP1 gene sequence of the nine Korean strains clustered most closely with the Japanese strain (AB759202).ConclusionThe data indicate that HPeV infection is predominant in young infants (<6 months) and that meningitis without pleocytosis was caused by both HPeV and EV infection in children

Scalable Production of Highly-Sensitive Nanosensors Based on Graphene Functionalized with a Designed G Protein-Coupled Receptor

We have developed a novel, all-electronic biosensor for opioids that consists of an engineered mu opioid receptor protein, with high binding affinity for opioids, chemically bonded to a graphene field-effect transistor to read out ligand binding. A variant of the receptor protein that provided chemical recognition was computationally redesigned to enhance its solubility and stability in an aqueous environment. A shadow mask process was developed to fabricate arrays of hundreds of graphene transistors with average mobility of ~1500 cm2 V-1 s-1 and yield exceeding 98%. The biosensor exhibits high sensitivity and selectivity for the target naltrexone, an opioid receptor antagonist, with a detection limit of 10 pg/mL.Comment: Nano Letters 201

Mucinous cystadenoma of the liver with ovarian-like stroma: the need for complete resection

Cystadenoma of the liver is a rare neoplasm. Although many cystadenomas are asymptomatic, symptoms can include abdominal pain, postprandial epigastric discomfort, and nausea. Dramatic changes in hepatic imaging techniques have been helpful for diagnosing cystic lesions of the liver, such as simple cyst, hydatid cyst, cystadenoma, cystadenocarcinoma, and metastatic neuroendocrine tumors. However, it remains difficult to differentiate cystadenoma from cystadenocarcinoma for multiseptated cystic hepatic lesions with papillary projection on computed tomography (CT) and magnetic resonance imaging (MRI). Here we report the case of a 47-year-old woman with several months of postprandial discomfort and abdominal fullness. CT and MRI revealed multiseptated cystic lesions with papillary excrescences. A left hemihepatectomy was performed. Histology showed a benign mucinous cystic tumor with ovarian-like stroma