Specifying angular momentum and center of mass for vacuum initial data sets

We show that it is possible to perturb arbitrary vacuum asymptotically flat spacetimes to new ones having exactly the same energy and linear momentum, but with center of mass and angular momentum equal to any preassigned values measured with respect to a fixed affine frame at infinity. This is in contrast to the axisymmetric situation where a bound on the angular momentum by the mass has been shown to hold for black hole solutions. Our construction involves changing the solution at the linear level in a shell near infinity, and perturbing to impose the vacuum constraint equations. The procedure involves the perturbation correction of an approximate solution which is given explicitly.Comment: (v2) a minor change in the introduction and a remark added after Theorem 2.1; (v3) final version, appeared in Comm. Math. Phy

SR4GN: A Species Recognition Software Tool for Gene Normalization

As suggested in recent studies, species recognition and disambiguation is one of the most critical and challenging steps in many downstream text-mining applications such as the gene normalization task and protein-protein interaction extraction. We report SR4GN: an open source tool for species recognition and disambiguation in biomedical text. In addition to the species detection function in existing tools, SR4GN is optimized for the Gene Normalization task. As such it is developed to link detected species with corresponding gene mentions in a document. SR4GN achieves 85.42% in accuracy and compares favorably to the other state-of-the-art techniques in benchmark experiments. Finally, SR4GN is implemented as a standalone software tool, thus making it convenient and robust for use in many text-mining applications. SR4GN can be downloaded at: http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/downloads/SR4G

TCMGeneDIT: a database for associated traditional Chinese medicine, gene and disease information using text mining

<p>Abstract</p> <p>Background</p> <p>Traditional Chinese Medicine (TCM), a complementary and alternative medical system in Western countries, has been used to treat various diseases over thousands of years in East Asian countries. In recent years, many herbal medicines were found to exhibit a variety of effects through regulating a wide range of gene expressions or protein activities. As available TCM data continue to accumulate rapidly, an urgent need for exploring these resources systematically is imperative, so as to effectively utilize the large volume of literature.</p> <p>Methods</p> <p>TCM, gene, disease, biological pathway and protein-protein interaction information were collected from public databases. For association discovery, the TCM names, gene names, disease names, TCM ingredients and effects were used to annotate the literature corpus obtained from PubMed. The concept to mine entity associations was based on hypothesis testing and collocation analysis. The annotated corpus was processed with natural language processing tools and rule-based approaches were applied to the sentences for extracting the relations between TCM effecters and effects.</p> <p>Results</p> <p>We developed a database, TCMGeneDIT, to provide association information about TCMs, genes, diseases, TCM effects and TCM ingredients mined from vast amount of biomedical literature. Integrated protein-protein interaction and biological pathways information are also available for exploring the regulations of genes associated with TCM curative effects. In addition, the transitive relationships among genes, TCMs and diseases could be inferred through the shared intermediates. Furthermore, TCMGeneDIT is useful in understanding the possible therapeutic mechanisms of TCMs via gene regulations and deducing synergistic or antagonistic contributions of the prescription components to the overall therapeutic effects. The database is now available at <url>http://tcm.lifescience.ntu.edu.tw/</url>.</p> <p>Conclusion</p> <p>TCMGeneDIT is a unique database that offers diverse association information on TCMs. This database integrates TCMs with biomedical studies that would facilitate clinical research and elucidate the possible therapeutic mechanisms of TCMs and gene regulations.</p

Different and Identical Features of Chondroblastic Osteosarcoma and Chondrosarcoma: Highlights on Radiography and Magnetic Resonance Imaging

BackgroundTo identify the different and identical features of 2 tumors with similar pathologic findings, chondroblastic osteosarcoma (OGS) and chondrosarcoma (CSA), with highlights on radiography and magnetic resonance imaging (MRI).MethodsTen patients with chondroblastic OGS and 10 patients with CSA were enrolled. After recording the tumor location, tumor morphology was evaluated for patterns of bony destruction, visible tumor matrix, and aggressive periosteal reactions, endosteal scalloping, cortical expansion, cortical breakthrough and pathologic fracture by radiographic analysis. Signal intensity changes, enhancement pattern, and tumor extensions were evaluated by MRI.ResultsThe mean patient ages were 24.7 and 56.7 years in patients with chondroblastic OGS and CSA, respectively (p = 0.001). Tumor occurrence was detected in the appendicular bones in 8 chondroblastic OGS and 3 CSA. Three chondroblastic OGS occurred around the knee (p = 0.003). In addition, there were 6 tumors arising from the metaphysis and 2 arising from the diaphysis in chondroblastic OGS patients. In CSA patients, 1 tumor arose in the metaphysis, 1 in the diaphysis, and 1 in the epiphysis (p = 0.039). On radiographs, visible bone-forming tumor matrix was present in 8 chondroblastic OGS, and coexistence of bone- and cartilage-forming patterns were detected in 2. Visible cartilage-forming tumor matrix was present in 7 CSA, and atypical radiodensity patterns were detected in 2 (p < 0.001). Aggressive periosteal reaction was present in 7 chondroblastic OGS, and non-aggressive periosteal reaction was found in 1 CSA (p = 0.008). MRI revealed the presence of a lobular structure of high signal intensity on T2-weighted images, and peripheral rim and septal enhancement pattern was noted in 2 chondroblastic OGS and 10 CSA patients. Inhomogeneous and marginal enhancement patterns were noted in 6 and 2 chondroblastic OGS, respectively (p = 0.001).ConclusionMetaphysis origin, bone-forming tumor matrix, aggressive periosteal reaction, and young patient age favored chondroblastic OGS. Some chondroblastic OGS showed radiologic and MRI appearances that were typical of CSA

The Informative Value of International University Rankings: Some Methodological Remarks

Global university rankings are critically discussed concerning their outcome, e.g., pointing to contradictory results. In contrast, this paper examines three issues with the example of three well known rankings (Shanghai, Times and Taiwan). First, on which methods, in particular on which indicators are they based? Second, are there fundamental deficits of concept and systematic biases? Third, can one predict good or bad ranking scores, based on the respective concept? In addition with the example of German universities there are two factors on performance measurement discussed, disciplinary cultures and size of the university. In sum, the usefulness of global rankings is considered to be highly questionable. Measures in science policy should not be legitimated with such rankings

Improved solar-driven photocatalytic performance of highly crystalline hydrogenated TiO₂ nanofibers with core-shell structure

Abstract Hydrogenated titanium dioxide has attracted intensive research interests in pollutant removal applications due to its high photocatalytic activity. Herein, we demonstrate hydrogenated TiO₂ nanofibers (H:TiO₂ NFs) with a core-shell structure prepared by the hydrothermal synthesis and subsequent heat treatment in hydrogen flow. H:TiO₂ NFs has excellent solar light absorption and photogenerated charge formation behavior as confirmed by optical absorbance, photo-Kelvin force probe microscopy and photoinduced charge carrier dynamics analyses. Photodegradation of various organic dyes such as methyl orange, rhodamine 6G and brilliant green is shown to take place with significantly higher rates on our novel catalyst than on pristine TiO₂ nanofibers and commercial nanoparticle based photocatalytic materials, which is attributed to surface defects (oxygen vacancy and Ti³⁺ interstitial defect) on the hydrogen treated surface. We propose three properties/mechanisms responsible for the enhanced photocatalytic activity, which are: (1) improved absorbance allowing for increased exciton generation, (2) highly crystalline anatase TiO₂ that promotes fast charge transport rate, and (3) decreased charge recombination caused by the nanoscopic Schottky junctions at the interface of pristine core and hydrogenated shell thus promoting long-life surface charges. The developed H:TiO₂ NFs can be helpful for future high performance photocatalysts in environmental applications