The Experts below are selected from a list of 28329 Experts worldwide ranked by ideXlab platform
Shi-yue Zhang - One of the best experts on this subject based on the ideXlab platform.
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Online-Storage recycling counter-current chromatography for preparative isolation of naphthaquinones from Arnebia euchroma (Royle) Johnst.
Journal of chromatography. A, 2016Co-Authors: Shi-yue ZhangAbstract:Counter-current Chromatography (CCC) has gradually become a popular method for preparative separation, especially in natural product isolation. As an effective separation method, one-dimensional (1D) CCC often results in insufficiently resolved peaks, due to limitations in the separation efficiency and peak capacity in an equipment. Therefore, two dimensional (2D)/multi-dimensional (multi-D) CCC strategies with recycling elution mode were developed to achieve successful separation of target compounds. However, the reported 2D or multi-D CCC approaches lead to experimental costs, complicated procedures, higher requirements for equipment, and increased time consumption. In this study, an Online-Storage recycling (OSR) CCC strategy was designed to achieve sequential recycling elution for multi-fractions of effluent in non-stop separation with single instrument using three 6-port valves and two Storage loops, which would be realized by introducing 2D or multi-D CCC method before. In this non-stop separation system, the fraction C of effluent was subjected to recycling separation while the other fractions (A and B) were storing Online, following which these two fractions were subjected to subsequent recycling separations in order, after the completion of the previous recycling elution. Then, six natural occurring naphthaquinone analogues, namely, shikonin (1), propionylshikonin (2), deoxyshikonin (3), isobutyrylshikonin (4), β, β-dimethylacrylshikonin (5) and isovalerylshikonin (6), were isolated from the crude extract of Arnebia euchroma in single run. The purities of all compounds were > 95.0% as determined by HPLC, and their structures were determined by means of UV, MS, (1)H NMR, (13)C NMR, and optical rotatory dispersion (ORD).
Jiang-er Lan - One of the best experts on this subject based on the ideXlab platform.
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High‐Speed Counter‐Current Chromatography with an Online Storage Technique for the Preparative Isolation and Purification of Dihydroflavonoids from Sophora alopecuroides L.
Phytochemical analysis : PCA, 2017Co-Authors: Zhong-lin Sun, Jiang-er LanAbstract:Introduction High-speed counter-current chromatography (HSCCC) is an efficient and non-absorption separation technique, but limitations still exist in simultaneous isolation of complex structures of natural products. Moreover, particular methods are various for different kinds of natural products. Objective A novel HSCCC strategy combined with an Online Storage recycling elution (OSR-CCC) technique was developed for the quick separation of naturally occurring dihydroflavonoids from the extract of the herb Sophora alopecuroides L. Methodology In the separation procedure, a Storage loop and two six-port valves were connected to a HSCCC system. Effluent A was subjected to an Online Storage loop and then to recycling separation three times after effluent B was collected in head-to-tail mode. After completion of the recycling separation of effluent A, the elution was switched to tail-to-head mode to collect effluent C. A biphasic solvent system of n-hexane/ethyl acetate/methanol/water (9:6:6:8, v/v/v/v) was used as the separation solvent during the whole elution. Results Six constituents were isolated simultaneously from the extract (200 mg) of S. alopecuroides by running HSCCC non-stop, and their purities were higher than 95.0%. Their structures were determined as the pterocarpan glycoside sophoratonkin (1) (10.0 mg) and five dihydroflavonoids, alopecurone F (2) (5.4 mg), lehmannin (3) (11.0 mg), alopecurone A (4) (35.0 mg), sophoraflavanone G (5) (21.0 mg), alopecurone B (6) (31.0 mg). Conclusion This recycling HSCCC method combined with an Online Storage technique could be a rapid, effective and simple approach to isolate stilbene-dihydroflavonoids from herbs of the Sophora genus simultaneously. Copyright © 2017 John Wiley & Sons, Ltd.
Xiao Wang - One of the best experts on this subject based on the ideXlab platform.
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Development of Online-Storage inner-recycling counter-current chromatography for the preparative separation of complex components of alkylphenols from sarcotesta of Ginkgo biloba L.
RSC Advances, 2018Co-Authors: Daijie Wang, Xiangyun Song, Huijiao Yan, Mengmeng Guo, Fu Ruiming, Hailong Jiang, Heng Zhu, Xiao WangAbstract:High-speed counter-current chromatography (HSCCC) is becoming an effective and non-absorptive separation method from natural products. Due to the insufficient separation efficiency, it is challenging to separate complex components, especially for compounds with similar KD values. In this study, a novel and effective Online-Storage inner-recycling CCC method was used to separate alkylphenols from the sarcotesta of Ginkgo biloba L. A two-phase solvent system of n-heptane/ethyl acetate/methanol/acetic acid (5 : 4 : 1 : 1, v/v) was used for HSCCC separation of 500 mg crude extracts. After the inner-recycling of two fractions coupled with pre-HPLC, five main ginkgolic acids (C13:0, C15:1, C17:2, C15:1, C17:1) coupled with bilobol (C15:1) and a mixture were obtained from a non-stop separation using a Storage loop and two six-way valves. This novel method was also evaluated and predicted by formula derivation. This method could be an effective, rapid, and simple approach to separate alkylphenols from the sarcotesta of G. biloba.
Minoru Uehara - One of the best experts on this subject based on the ideXlab platform.
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Cloud Search Engine for IaaS
Transactions on Computational Collective Intelligence X, 2013Co-Authors: Yuuta Ichikawa, Minoru UeharaAbstract:Cloud based Online Storage enables the Storage of massive data. In these systems, a full text search engine is very important for finding documents. In this paper, we propose a distributed search engine suitable for searching a cloud. In our previous work, we developed a distributed search engine, the cooperative search engine (CSE). We now extend the CSE to search clouds. In a cloud, elasticity and reliability are important. We realize these by employing consistent hashing for distributed index files in the cloud. In this paper, we describe the improved CSE architecture and its implementation for a cloud search.
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NBiS - Storage-Side Computing for Data Management in Private and Public Clouds
2012 15th International Conference on Network-Based Information Systems, 2012Co-Authors: Tatsunori Takahashi, Hidenao Tanaka, Shinichiro Kibe, Minoru UeharaAbstract:In cloud era, data is centralized into cloud. Indeed, many Online Storage services are provided. However, the communication delay is long because the network connected devices to cloud does not have enough bandwidth. So, a mechanism of processing cloud-side is required. We call such a mechanism that processes data near Online Storage gStorage-side computing.h In this paper, we describe an electrical book management system as an example of Storage-side computing. Recently, electrical book becomes popular. In our electrical book management system, we assume that a user stores his own personal electrical book formatted as PDF in several different Online Storage services. In such a situation, a user wants to manage them in an integrated way. Our system gives users such a service. Our system is allowed to be accessed from various kinds of devices such as Smart Phone and can process data during even off-line.
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NBiS - Performance Evaluation of 2FT RAID
2011 14th International Conference on Network-Based Information Systems, 2011Co-Authors: Yuji Nakamura, Minoru UeharaAbstract:Recently, there has been increased demand for large-scale Online Storage for clouds, life logs, and other applications. Previously, we developed the VLSD (Virtual Large-Scale Disks) toolkit for constructing large-scale Online Storage, using RAID to realize reliable Storage. RAID5 is commonly used, but it is not adequate for large-scale Online Storage because it provides only level 1 fault tolerance (1FT). Currently, many Storage appliances employ more than 1FT RAID, such as RAID6. However, there are several RAID classes with greater tolerance than 1FT. In previous works, we developed another 2FT RAID, RAID4PQ, which is similar to RAID6 in the sense that it uses P+Q parities. However, it differs from RAID6 in that it has dedicated double parity. Furthermore, RAID RDP is also a 2FT RAID, in which the 2 parities are row and diagonal parities (RDP). In this paper, we implement these RAID types as VLSD classes and compare their performance.
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BWCCA - Distributed Search Engine for an IaaS Based Cloud
2011 International Conference on Broadband and Wireless Computing Communication and Applications, 2011Co-Authors: Yuuta Ichikawa, Minoru UeharaAbstract:Cloud based Online Storage enables the Storage of massive data. In these systems, a full text search engine is very important for finding documents. In this paper, we propose a distributed search engine suitable for searching a cloud. In our previous work, we developed a distributed search engine, the cooperative search engine (CSE). We now extend the CSE to search clouds. In a cloud, elasticity and reliability are important. We realize these by employing consistent hashing for distributed index files in the cloud. In this paper, we describe the improved CSE architecture and its implementation for a cloud search.
Zhong-lin Sun - One of the best experts on this subject based on the ideXlab platform.
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High‐Speed Counter‐Current Chromatography with an Online Storage Technique for the Preparative Isolation and Purification of Dihydroflavonoids from Sophora alopecuroides L.
Phytochemical analysis : PCA, 2017Co-Authors: Zhong-lin Sun, Jiang-er LanAbstract:Introduction High-speed counter-current chromatography (HSCCC) is an efficient and non-absorption separation technique, but limitations still exist in simultaneous isolation of complex structures of natural products. Moreover, particular methods are various for different kinds of natural products. Objective A novel HSCCC strategy combined with an Online Storage recycling elution (OSR-CCC) technique was developed for the quick separation of naturally occurring dihydroflavonoids from the extract of the herb Sophora alopecuroides L. Methodology In the separation procedure, a Storage loop and two six-port valves were connected to a HSCCC system. Effluent A was subjected to an Online Storage loop and then to recycling separation three times after effluent B was collected in head-to-tail mode. After completion of the recycling separation of effluent A, the elution was switched to tail-to-head mode to collect effluent C. A biphasic solvent system of n-hexane/ethyl acetate/methanol/water (9:6:6:8, v/v/v/v) was used as the separation solvent during the whole elution. Results Six constituents were isolated simultaneously from the extract (200 mg) of S. alopecuroides by running HSCCC non-stop, and their purities were higher than 95.0%. Their structures were determined as the pterocarpan glycoside sophoratonkin (1) (10.0 mg) and five dihydroflavonoids, alopecurone F (2) (5.4 mg), lehmannin (3) (11.0 mg), alopecurone A (4) (35.0 mg), sophoraflavanone G (5) (21.0 mg), alopecurone B (6) (31.0 mg). Conclusion This recycling HSCCC method combined with an Online Storage technique could be a rapid, effective and simple approach to isolate stilbene-dihydroflavonoids from herbs of the Sophora genus simultaneously. Copyright © 2017 John Wiley & Sons, Ltd.
