Efficient Peer-to-Peer Content Sharing for Learning in Virtual Worlds

Virtual world technologies provide new and immersive space for learning, training, and education. They are enabled by the content creation and content sharing function for allowing users to create and interoperate various learning objects. Unfortunately, virtual world content sharing based on persistent virtual world content storage, to the best of our knowledge, does not exist. In this paper, we address this problem by proposing a content sharing scheme based on Virtual Net, a virtual world persistency framework. For efficient content retrieval, three strategies have been proposed to reduce communication overhead and content load delay.By integrating these strategies, a virtual world content search and retrieval algorithm has been devised. The experiment results verify the effectiveness of the algorithm

Virtual Net: a Decentralized Architecture for Interaction in Mobile Virtual Worlds

With the development of mobile technology, mobile virtual worlds have attracted massive users. To improve scalability, a peer-to-peer virtual world provides the solution to accommodate more users without increasing hardware investment. In mobile settings, however, existing P2P solutions are not applicable due to the unreliability of mobile devices and the instability of mobile networks. To address the issue, a novel infrastructure model, called Virtual Net, is proposed to provide fault-tolerance in managing user content and object state. In this paper, the key problem, namely object state update, is resolved to maintain state consistency and high interaction responsiveness. This work is important in implementing a scalable mobile virtual world

Designing Colloidal Molecules with Microfluidics

International audienceThe creation of new colloidal materials involves the design of functional building blocks. Here, a microfl uidic method for designing building blocks one by one, at high throughput, with a broad range of shapes is introduced. The method exploits a coupling between hydrodynamic interactions and depletion forces that controls the confi gurational dynamics of droplet clusters traveling in microfl uidic channels. Droplet clusters can be solidifi ed in situ with UV. By varying the fl ow parameters, clusters are prescribed a given size, geometry, chemical and/or magnetic heterogeneities enabling local bonding. Compact structures (chains, triangles, diamonds, tetrahedrons,...) and non-compact structures, such as crosses and T, diffi cult to obtain with current techniques are produced. Size dispersions are small (2%) and throughputs are high (30 000 h −1). The work opens a new pathway, based on microfl uidics, for designing colloidal building blocks with a potential to enable the creation of new materials

Efficient Peer-to-Peer Content Sharing for Learning in Virtual Worlds

Virtual world technologies provide new and immersive space for learning, training, and education. They are enabled by the content creation and content sharing function for allowing users to create and interoperate various learning objects. Unfortunately, virtual world content sharing based on persistent virtual world content storage, to the best of our knowledge, does not exist. In this paper, we address this problem by proposing a content sharing scheme based on Virtual Net, a virtual world persistency framework. For efficient content retrieval, three strategies have been proposed to reduce communication overhead and content load delay. By integrating these strategies, a virtual world content search and retrieval algorithm has been devised. The experiment results verify the effectiveness of the algorithm

A META-ANALYSIS OF ABNORMAL GLUCOSE METABOLISM IN FIRST-EPISODE DRUG-NAIVE SCHIZOPHRENIA

Background: Patients with schizophrenia exhibit a higher mortality rate compared with the general population. This mortality has been attributed predominantly by the high risk of type 2 diabetes mellitus in the patients. We aimed to assess the inherent risk of glucose metabolism abnormalities in first-episode drug-naïve schizophrenia. Subjects and methods: We searched English database (PubMed, EMBASE, MEDLINE, Cochrane Library databases) and Chinese database (Wan Fang Data, CBM disc, VIP, and CNKI) from their inception until Jul 2018 for case-control studies examining glucose metabolism abnormalities. Measurements, such as fasting plasma glucose levels, fasting plasma insulin levels, insulin resistance and HbA1c levels in first episode antipsychotic-naive patients were used to test for prediabetes. Standardized/weighted mean differences and 95% confidence intervals were calculated and analyzed. Results: 19 studies (13 in English and 6 in Chinese) consisting of 1065 patients and 873 controls were included. Fasting plasma glucose levels (95% CI; 0.02 to 0.29; P=0.03), 2 h plasma glucose levels after an OGTT (95% CI; 0.63 to 1.2; P<0.00001), fasting plasma insulin levels (95% CI; 0.33 to 0.73; P<0.00001), insulin resistance (95% CI; 0.29 to 0.6; P<0.00001) in patients with firstepisode schizophrenia were significant elevated. There was no significant difference in HbA1c level (95% CI; -0.34 to 0.18; P=0.54) in patients with first-episode schizophrenia compared with controls. Conclusions: This meta-analysis showed that glucose metabolism was impaired in patients with first-episode schizophrenia. Higher quality studies with larger samples are warranted to confirm these findings

Significant contrasts in aerosol acidity between China and the United States

Aerosol acidity governs several key processes in aerosol physics and chemistry, thus affecting aerosol mass and composition and ultimately climate and human health. Previous studies have reported aerosol pH values separately in China and the United States (USA), implying different aerosol acidity between these two countries. However, there is debate about whether mass concentration or chemical composition is the more important driver of differences in aerosol acidity. A full picture of the pH difference and the underlying mechanisms responsible is hindered by the scarcity of simultaneous measurements of particle composition and gaseous species, especially in China. Here we conduct a comprehensive assessment of aerosol acidity in China and the USA using extended ground-level measurements and regional chemical transport model simulations. We show that aerosols in China are significantly less acidic than in the USA, with pH values 1&ndash;2&nbsp;units higher. Based on a proposed multivariable Taylor series method and a series of sensitivity tests, we identify major factors leading to the pH difference. Compared to the USA, China has much higher aerosol mass concentrations (gas + particle, by a factor of 8.4 on average) and a higher fraction of total ammonia (gas + particle) in the aerosol composition. Our assessment shows that the differences in mass concentrations and chemical composition play equally important roles in driving the aerosol pH difference between China and the USA &ndash; increasing the aerosol mass concentrations (by a factor of 8.4) but keeping the relative component contributions the same in the USA as the level in China increases the aerosol pH by &sim;&thinsp;1.0&nbsp;units and further shifting the chemical composition from US conditions to China's that are richer in ammonia increases the aerosol pH by &sim;&thinsp;0.9 units. Therefore, China being both more polluted than the USA and richer in ammonia explains the aerosol pH difference. The difference in aerosol acidity highlighted in the present study implies potential differences in formation mechanisms, physicochemical properties, and toxicity of aerosol particles in these two countries. &nbsp;</p

A two-step lineage reprogramming strategy to generate functionally competent human hepatocytes from fibroblasts

Terminally differentiated cells can be generated by lineage reprogramming, which is, however, hindered by incomplete conversion with residual initial cell identity and partial functionality. Here, we demonstrate a new reprogramming strategy by mimicking the natural regeneration route, which permits generating expandable hepatic progenitor cells and functionally competent human hepatocytes. Fibroblasts were first induced into human hepatic progenitor-like cells (hHPLCs), which could robustly expand in vitro and efficiently engraft in vivo. Moreover, hHPLCs could be efficiently induced into mature human hepatocytes (hiHeps) in vitro, whose molecular identity highly resembles primary human hepatocytes (PHHs). Most importantly, hiHeps could be generated in large quantity and were functionally competent to replace PHHs for drug-metabolism estimation, toxicity prediction and hepatitis B virus infection modeling. Our results highlight the advantages of the progenitor stage for successful lineage reprogramming. This strategy is promising for generating other mature human cell types by lineage reprogramming.</p

Portable fluorescence detection system

This Master of Science Dissertation describes the development and design of low cost portable fluorescence detection system that can detect the low concentrations of biological analytes of interest to distributed diagnosis and home healthcare. The whole system is composed of 4 modules: a fluorescence excitation and detection module, a signal processing module, a data acquisition module and a pedestal module.Master of Science (Computer Control and Automation