Distributed Caching for Complex Querying of Raw Arrays

As applications continue to generate multi-dimensional data at exponentially increasing rates, fast analytics to extract meaningful results is becoming extremely important. The database community has developed array databases that alleviate this problem through a series of techniques. In-situ mechanisms provide direct access to raw data in the original format---without loading and partitioning. Parallel processing scales to the largest datasets. In-memory caching reduces latency when the same data are accessed across a workload of queries. However, we are not aware of any work on distributed caching of multi-dimensional raw arrays. In this paper, we introduce a distributed framework for cost-based caching of multi-dimensional arrays in native format. Given a set of files that contain portions of an array and an online query workload, the framework computes an effective caching plan in two stages. First, the plan identifies the cells to be cached locally from each of the input files by continuously refining an evolving R-tree index. In the second stage, an optimal assignment of cells to nodes that collocates dependent cells in order to minimize the overall data transfer is determined. We design cache eviction and placement heuristic algorithms that consider the historical query workload. A thorough experimental evaluation over two real datasets in three file formats confirms the superiority -- by as much as two orders of magnitude -- of the proposed framework over existing techniques in terms of cache overhead and workload execution time

Calpain Activator Dibucaine Induces Platelet Apoptosis

Calcium-dependent calpains are a family of cysteine proteases that have been demonstrated to play key roles in both platelet glycoprotein Ibα shedding and platelet activation and altered calpain activity is associated with thrombotic thrombocytopenic purpura. Calpain activators induce apoptosis in several types of nucleated cells. However, it is not clear whether calpain activators induce platelet apoptosis. Here we show that the calpain activator dibucaine induced several platelet apoptotic events including depolarization of the mitochondrial inner transmembrane potential, up-regulation of Bax and Bak, down-regulation of Bcl-2 and Bcl-XL, caspase-3 activation and phosphatidylserine exposure. Platelet apoptosis elicited by dibucaine was not affected by the broad spectrum metalloproteinase inhibitor GM6001. Furthermore, dibucaine did not induce platelet activation as detected by P-selectin expression and PAC-1 binding. However, platelet aggregation induced by ristocetin or α-thrombin, platelet adhesion and spreading on von Willebrand factor were significantly inhibited in platelets treated with dibucaine. Taken together, these data indicate that dibucaine induces platelet apoptosis and platelet dysfunction

Thermal Migration Behavior of Na⁺, Cu²⁺ and Li⁺ in Montmorillonite

The main aim of this paper is to study the cation fixation sites in montmorillonite after heating at different temperatures. Montmorillonite was used to adsorb cations (Na+, Cu2+ and Li+) in the solution, and the montmorillonite-adsorbed cations were heated at different temperatures (unheated, 100 °C, 200 °C and 300 °C) for 25 h. Subsequently, the basal spacing of montmorillonite treated at different temperatures was monitored by X-ray diffraction (XRD). The exchangeable cationic content (Na+, Cu2+ and Li+) in montmorillonite was determined based on an inductively coupled plasma emission spectrometer (ICP-OES). In addition, the stretching and bending vibration changes in the OH group and the Si-O bond in montmorillonite were detected by Fourier transform infrared spectroscopy (FTIR). The vibration changes were related to the cation fixation sites. The XRD data showed that when the heating temperature reached 200 °C, the structure of montmorillonite adsorbing Li+ and Cu2+ ions completely collapsed, but the layer spacing of montmorillonite adsorbing Na+ decreased slightly, which indicated that Li+ and Cu2+ were more easily able to enter the crystal structure. The ICP-OES results showed that the contents of exchangeable Na+, Cu2+ and Li+ in montmorillonite decreased with the increase in heating temperature, and Li+ was more easily fixed by montmorillonite than Na+ and Cu2+. The FTIR data showed that when montmorillonite adsorbed with Li+ was heated at more than 200 °C, a new OH stretching vibration band appeared at 3971 cm−1, which may be caused by the migration of Li+ into the octahedral vacancy to form a local trioctahedral structure. Na+ has a large radius; it can only be fixed near the OH group and may not enter the tetrahedron/octahedron of montmorillonite. The number of charges carried by Cu2+ is high and the dehydration enthalpy of hydrated Cu2+ is high. When the heating temperature was greater than 200 °C, Cu2+ mainly entered the hexagonal cavity of the tetrahedron and caused slight changes in the OH bending vibration. The vibration of the Si-O bond hardly changed after montmorillonite adsorbed Na+, but the stretching vibration peak of the Si-O bond moved to the high value region after adsorbing Cu2+ and Li+, which was speculated to be related to the migration of Cu2+ and Li+ into the crystal structure

Crystallization and preliminary X-ray crystallographic studies of O-methyltransferase from Anabaena PCC 7120

The O-methyltransferase (OMT) from the Anabaena PCC 7120 has been overexpressed in a soluble form in E. coli, purified and crystallized. The crystals belonged to space group C2221 and diffracted to 2.4 Å resolution

Distributed Caching for Complex Querying of Raw Arrays

As applications continue to generate multi-dimensional data at exponentially increasing rates, fast analytics to extract meaningful results is becoming extremely important. The database community has developed array databases that alleviate this problem through a series of techniques. In-situ mechanisms provide direct access to raw data in the original format---without loading and partitioning. Parallel processing scales to the largest datasets. In-memory caching reduces latency when the same data are accessed across a workload of queries. However, we are not aware of any work on distributed caching of multi-dimensional raw arrays. In this paper, we introduce a distributed framework for cost-based caching of multi-dimensional arrays in native format. Given a set of files that contain portions of an array and an online query workload, the framework computes an effective caching plan in two stages. First, the plan identifies the cells to be cached locally from each of the input files by continuously refining an evolving R-tree index. In the second stage, an optimal assignment of cells to nodes that collocates dependent cells in order to minimize the overall data transfer is determined. We design cache eviction and placement heuristic algorithms that consider the historical query workload. A thorough experimental evaluation over two real datasets in three file formats confirms the superiority -- by as much as two orders of magnitude -- of the proposed framework over existing techniques in terms of cache overhead and workload execution time