A Comparative Study of Flux Limiters Using New Numerical Methods in Unsteady Supersonic Flows

In this study, partition of the energy equation in the Euler equations is expanded in the form of ideal mixture gas through the finite-volume method in order to discuss questions faced in the Riemann approximation solver. Through the AUSMDV numerical flux scheme with different flux limiters and types of gradient, we want to improve the calculation accuracy and reduce the nonphysical oscillation problem. Based on the AUSMDV scheme, We modify the energy equation of the ideal mixture gas which was proposed by Ton [8 V. T. Ton , Improved Shock-Capturing Methods for Multicomponent and Reacting Flows , J. Comput. Phys. , vol. 128 , pp. 237 – 235 , 1996 .[Crossref], [Web of Science ®] , [Google Scholar]]. For the pressure and velocity gradient of source term Q, we establish a new method of gradient control to test whether it can make progress in the nonphysical numerical oscillation problem.     

Sesquiterpenes from the rhizome of Curcuma longa with inhibitory activity on superoxide generation and elastase release by neutrophils

Six new sesquiterpenes, curculonone A (1), curculonone B (2), curculonone C (3), curculonone D (4), 6α-hydroxycurcumanolide A (5), and 1,10-dehydro-10-deoxy-9-oxozedoarondiol (6), have been isolated from the rhizome of Curcuma longa, together with 19 known compounds. The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1, 2, 5, 12, 15, 16, and 23 exhibited inhibition (IC₅₀ ? 18.22 μM) of superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). Compounds 5, 12–16, and 23 inhibited fMLP/CB-induced elastase release with IC₅₀ values ? 14.28 μM.     

Computer-Aided Design and Synthesis of (Functionalized quinazoline)–(α-substituted coumarin)–arylsulfonate Conjugates against Chikungunya Virus

Chikungunya virus (CHIKV) has repeatedly spread via the bite of an infected mosquito and affected more than 100 countries. The disease poses threats to public health and the economy in the infected locations. Many efforts have been devoted to identifying compounds that could inhibit CHIKV. Unfortunately, successful clinical candidates have not been found yet. Computations through the simulating recognition process were performed on complexation of the nsP3 protein of CHIKV with the structures of triply conjugated drug lead candidates. The outcomes provided the aid on rational design of functionalized quinazoline-(α-substituted coumarin)-arylsulfonate compounds to inhibit CHIKV in Vero cells. The molecular docking studies showed a void space around the β carbon atom of coumarin when a substituent was attached at the α position. The formed vacancy offered a good chance for a Michael addition to take place owing to steric and electronic effects. The best conjugate containing a quinazolinone moiety exhibited potency with EC₅₀ = 6.46 μM, low toxicity with CC₅₀ = 59.7 μM, and the selective index (SI) = 9.24. Furthermore, the corresponding 4-anilinoquinazoline derivative improved the anti-CHIKV potency to EC₅₀ = 3.84 μM, CC₅₀ = 72.3 μM, and SI = 18.8. The conjugate with 4-anilinoquinazoline exhibited stronger binding affinity towards the macro domain than that with quinazolinone via hydrophobic and hydrogen bond interactions.     

Identification of a Putative CodY Regulon in the Gram-Negative Phylum Synergistetes

CodY is a dominant regulator in low G + C, Gram-positive Firmicutes that governs the regulation of various metabolic pathways and cellular processes. By using various bioinformatics analyses and DNA affinity precipitation assay (DAPA), this study confirmed the presence of CodY orthologues and corresponding regulons in Gram-negative Synergistetes. A novel palindromic sequence consisting of AT-rich arms separated by a spacer region of variable length and sequence was identified in the promoters of the putative codY-containing operons in Synergistetes. The consensus sequence from genera Synergistes and Cloacibacillus (5′-AATTTTCTTAAAATTTCSCTTGATATTTACAATTTT) contained three AT-rich regions, resulting in two palindromic sequences; one of which is identical to Firmicutes CodY box (5′-AATTTTCWGAAAATT). The function of the consensus sequence was tested by using a recombinant CodY protein (His-CodY_DSM) of Cloacibacillus evryensis DSM19522 in DAPA. Mutations in the central AT-rich sequence reduced significantly the binding of His-CodY_DSM, whereas mutations in the 5′ or 3′ end AT-rich sequence slightly reduced the binding, indicating that CodY_DSM could recognize both palindromic sequences. The proposed binding sequences were found in the promoters of multiple genes involved in amino acids biosynthesis, metabolism, regulation, and stress responses in Synergistetes. Thus, a CodY-like protein from Synergistetes may function similarly to Firmicutes CodY.     

FETCH: A cloud-native searchable encryption scheme enabling efficient pattern search on encrypted data within cloud services

Searchable encryption (SE) is considered important as it provides both confidentiality and searchability for the data stored in semi-trusted environments such as cloud. However, it is rarely deployed because most SE schemes are not native to cloud services as they require database modifications. In this paper, we present an SE scheme called Frequency-Eliminated Trapdoor-Character Hopping (FETCH) that, based on novel common-conditioned-subsequence-preserving (CCSP) techniques, is able to work natively with off-the-shelf databases and supports wildcard-based pattern search on encrypted data thereof. In fact, with the CCSP techniques, we transform the problem of wildcard SE searching into a problem of subsequence searching, which is solved fast in most databases and thus fits well with cloud services in general. Although in our security analysis, CCSP removes the possibility of obtaining theoretical indistinguishability between indexed items, we show that FETCH does provide adequate confidentiality protection and fares much better than other existing wildcard SE schemes in terms of query performance, storage overhead, and deployment complexity. In particular, FETCH is able to efficiently handle data sets whose size is multiple orders of magnitude larger than those that existing schemes can comfortably support.     

On‐demand data co‐allocation with user‐level cache for grids

Conventional remote data access middlewares usually provide client applications with either a pre‐staging scheme or an on‐demand access scheme to fetch data. The pre‐staging scheme uses parallel downloads to fetch a completed input file from multiple data sources, even when only a tiny file fragment is required. Such a transfer scheme consumes unnecessary data transmission time and storage space. In contrast, the on‐demand scheme downloads only the required data blocks from a single data source and does not fully utilize the downstream bandwidth of the computing nodes. This paper presents a middleware called ‘Spigot’ that facilitates legacy (grid‐unaware) applications to transparently access remote data by using native I/O function calls. Spigot uses the on‐demand concept to avoid unnecessary data transfer and adopts a co‐allocation download algorithm to improve the data transfer performance. Moreover, it uses the pre‐fetching strategy to reduce the data waiting time by overlapping data acquisition and data processing. It also provides the client application with its own user‐level cache, which is advantageous since a larger cache space is available in comparison with the kernel‐level cache. Further, it is easy to maintain data consistency between Spigot nodes. The experimental results indicate that Spigot achieves superior performance in reducing the data waiting time than the pre‐staging and the on‐demand access schemes. Copyright © 2010 John Wiley & Sons, Ltd.     

Pain scores estimation using surgical pleth index and long short-term memory neural networks

Artificial Life and Robotics - Pain monitoring is crucial to provide proper healthcare for patients during general anesthesia (GA). In this study, photoplethysmographic waveform amplitude (PPGA),...