A comparative study on production of middle chain diacylglycerol through enzymatic esterification and glycerolysis

Dan-Jing Hu,Yong-Mei Xia,Jun-Ming Chen 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.5

A comparative study on lipase catalyzed production of middle chain diacylglycerol was conducted with esterification of glycerol and glycerolysis of triacylglycerol, respectively, in which high diacylglycerol yield and high acyl donor conversion are two desired goals. The esterification provided much higher acyl donor conversion than glycerolysis (with the conversion of 94.42% and 74.21%, respectively). The esterification in packed bed reactor produced more diacylglycerol than that in batch reactor (with relative content in the product of 77.26% and 45.45%, respectively). Mass transfer is one of the limitations during the procedure. Microwave irradiation provides higher reaction rate and selectivity in glycerolysis.

Compressive Sampling Orthogonal Matching Pursuit Algorithm Based on Peak Signal to Noise Ratio

Hu Dan 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.8

In order to improve signal reconstruction accuracy, a CoSaMP (Compressive Sampling Matching Pursuit) algorithm based on peak signal to noise ratio is proposed in allusion to the disadvantages of CoSaMP algorithm. Firstly, the discrete cosine wave transform is improved to initially estimate the signal sparseness; secondly, the optimum iteration number is determined according to the peak signal to noise ratio to gradually approach to the real sparseness of the signal for signal reconstruction; finally, the simulation experiment is adopted to analyze the algorithm performance. The result shows: compared with CoSaMP algorithm and other improved CoSaMP algorithms, the proposed algorithm can not only obtain more ideal reconstruction effect, but also improve the reconstruction success probability and reduce the reconstruction time, thus having higher reconstruction efficiency.

Rapid and Visual Detection of Vibrio parahaemolyticus in Aquatic Foods Using blaC_ARB-17 Gene-Based Loop-Mediated Isothermal Amplification with Lateral Flow Dipstick (LAMP-LFD)

( Yuan-qing Hu ),( Xian-hui Huang ),( Li-qing Guo ),( Zi-chen Shen ),( Lin-xue Lv ),( Feng-xia Li ),( Zan-hu Zhou ),( Dan-feng Zhang ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.12

Vibrio parahaemolyticus is recognized as one of the most important foodborne pathogens responsible for gastroenteritis in humans. The bla_CARB-17 gene is an intrinsic β-lactamase gene and a novel species-specific genetic marker of V. parahaemolyticus. In this study, a loop-mediated isothermal amplification (LAMP) assay combined with a lateral flow dipstick (LFD) was developed targeting this bla_CARB-17 gene. The specificity of LAMP-LFD was ascertained by detecting V. parahaemolyticus ATCC 17802 and seven other non-V. parahaemolyticus strains. Finally, the practicability of LAMP-LFD was confirmed by detection with V. parahaemolyticus-contaminated samples and natural food samples. The results showed that the optimized reaction parameters of LAMP are as follows: 2.4 mmol/l Mg²⁺, 0.96 mmol/l dNTPs, 4.8 U Bst DNA polymerase, and an 8:1 ratio of inner primer to outer primer, at 63℃ for 40 min. The optimized reaction time of the LFD assay is 60 min. Cross-reactivity analysis with the seven non-V. parahaemolyticus strains showed that LAMP-LFD was exclusively specific for V. parahaemolyticus. The detection limit of LAMP-LFD for V. parahaemolyticus genomic DNA was 2.1 × 10^-4 ng/μl, corresponding to 630 fg/reaction and displaying a sensitivity that is 100-fold higher than that of conventional PCR. LAMP-LFD in a spiking study revealed a detection limit of approximately 6 CFU/ml, which was similar with conventional PCR. The developed LAMP-LFD specifically identified the 10 V. parahaemolyticus isolates from 30 seafood samples, suggesting that this LAMP-LFD may be a suitable diagnostic method for detecting V. parahaemolyticus in aquatic foods.

A MIMO-Based Collision Mitigation Scheme in Uplink WLANs

Hu Jin,Bang Chul Jung,Ho Young Hwang,Dan Keun Sung IEEE 2008 IEEE communications letters Vol.12 No.6

<P>Although there exist random backoff schemes in WLANs, a collision problem among stations (STAs) is one of the critical factors that degrade the performance of WLAN systems. To mitigate this collision problem, a MIMO-based uplink collision mitigation scheme is proposed by utilizing additional degrees of freedom through multiple antennas, and, consequently, enhances the system performance. Analysis and simulation results show that there is at least 30% throughput enhancement in a basic service set (BSS) with more than 10 STAs, compared to the performance of conventional WLANs in case of saturation traffic.</P>

Design of Space Search-Optimized Polynomial Neural Networks with the Aid of Ranking Selection and L2-norm Regularization

Dan Wang,Sung-Kwun Oh,Eun-Hu Kim 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.4

The conventional polynomial neural network (PNN) is a classical flexible neural structure and self-organizing network, however it is not free from the limitation of overfitting problem. In this study, we propose a space search-optimized polynomial neural network (ssPNN) structure to alleviate this problem. Ranking selection is realized by means of ranking selection-based performance index (RS_PI) which is combined with conventional performance index (PI) and coefficients based performance index (CPI) (viz. the sum of squared coefficient). Unlike the conventional PNN, L2-norm regularization method for estimating the polynomial coefficients is also used when designing the ssPNN. Furthermore, space search optimization (SSO) is exploited here to optimize the parameters of ssPNN (viz. the number of input variables, which variables will be selected as input variables, and the type of polynomial). Experimental results show that the proposed ranking selection-based polynomial neural network gives rise to better performance in comparison with the neuron fuzzy models reported in the literatures.

Central Control over Distributed Service Function Path

( Dan Li ),( Julong Lan ),( Yuxiang Hu ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.2

Service Function Chaining (SFC) supports services through linking an ordered list of functions. There may be multiple instances of the same function, which provides a challenge to select available instances for all the functions in an SFC and generate a specific Service Function Path (SFP). Aiming to solve the problem of SFP selection, we propose an architecture consisting of distributed SFP algorithm and central control mechanism. Nodes generate distributed routings based on the first function and destination node in each service request. Controller supervises all of the distributed routing tables and modifies paths as required. The architecture is scalable, robust and quickly reacts to failures because of distributed routings. Besides, it enables centralized and direct control of the forwarding behavior with the help of central control mechanism. Simulation results show that distributed routing tables can generate efficient SFP and the average cost is acceptable. Compared with other algorithms, our design has a good performance on average cost of paths and load balancing, and the response delay to service requests is much lower.

A Tradeoff Between Single-User and Multi-User MIMO Schemes in Multi-Rate Uplink WLANs

Hu Jin,Bang Chul Jung,Dan Keun Sung IEEE 2011 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.10 No.10

<P>Due to high spectral-efficiency of multiple-input multiple-output (MIMO) transmission techniques, IEEE 802.11n WLAN system adopted a single-user MIMO (SU-MIMO) scheme in which multiple symbol streams are transmitted from a single station (STA) to enhance the system performance. On the other hand, recently, adoption of a multi-user MIMO (MU-MIMO) scheme for multi-packet reception (MPR) in uplink WLAN has also attracted attention. The SU-MIMO scheme achieves a MIMO multiplexing gain at physical (PHY) layer while the MU-MIMO scheme achieves a MIMO multiplexing gain at medium access control (MAC) layer. Thus, there is a fundamental question which scheme is a better solution for uplink WLANs and, in this paper, we analyze and compare these two schemes with random STA distribution scenarios. Moreover, with the adaptation of MAC layer parameters, we also analyze and compare the maximum throughput performance of both the SU- and MU-MIMO schemes in uplink WLANs and we find a proper decision criterion to select the MIMO mode in uplink WLANs.</P>

Determination of Tocopherol Contents in Refined Edible Oils Using an HPLC Method

Hu, Jiang-Ning,Zhu, Xue-Mei,Adhikari, Prakash,Li, Dan,Kim, In-Hwan,Lee, Ki-Teak The Korean Society of Food Science and Nutrition 2009 Preventive Nutrition and Food Science Vol.14 No.3

A high-performance liquid chromatography method was applied to determine the contents of tocopherols in edible oils using a LiChrosorb DIOL HPLC column and hexane fortified with 0.1% acetic acid in an isocratic mode. The validation of the method included tests for linearity, sensitivity, accuracy, precision, and recovery. All calibration curves showed good linear regression ($r^2$>0.9995) within the tested ranges. The established method offered good precision and accuracy with overall intra-day and inter-day variations of 0.94$\sim$4.27 and 1.77$\sim$ 4.88%, respectively. The tocopherol recoveries ranged from 91.44$\sim$108.90%. Subsequently, the method was successfully applied to qualitatively and quantitatively determine the total contents of $\alpha$, $\gamma$, and $\delta$-tocopherols in 12 selected refined edible oils, showing a range of 0.92 to 188.71 mg/100 g.

Serum IL-33 as a Diagnostic and Prognostic Marker in Non-small Cell Lung Cancer

Hu, Liang-An,Fu, Yu,Zhang, Dan-Ni,Zhang, Jie Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Background: Interleukin-33 (IL-33) has recently been implicated in tumor immunity. The aim of this study was to explore the clinical role of serum IL-33 in patients with non-small-cell lung cancer (NSCLC). Methods: Sera collected from 250 healthy volunteers (HV), 256 patients with benign lung diseases (BLD) and 262 NSCLC cases were subjected to IL-33 ELISA and relationships between serum IL-33 and clinical characteristics were evaluated. Results: Circulating IL-33 levels were higher in the NSCLC group in comparison with the HV and BLD groups (p<0.001). Using a cut-off level 68 pg/ml (95% specificity in the HV group), IL-33 showed a good diagnostic performance for NSCLC. Multivariate survival analysis indicated that serum IL-33 was an independent prognostic factor in the entire NSCLC group [hazards ratio (HR) = 0.64 for low versus high IL-33 levels, 95% confidence interval (CI) 0.50-0.82; p<0.001] and in 165 selected patients with locally advanced or metastatic disease receiving chemoradiotherapy or chemotherapy (HR 0.70, 95% CI 0.52-0.94; p=0.013). Conclusions: IL-33 is a promising potential diagnostic and prognostic marker in NSCLC, independent of the therapeutic intervention.

Optimal Rate Selection for Persistent Scheduling with HARQ in Time-Correlated Nakagami-m Fading Channels

Hu Jin,Changgi Cho,Nah-Oak Song,Dan Keun Sung IEEE 2011 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.10 No.2

<P>Orthogonal frequency division multiple access (OFDMA) systems, such as IEEE 802.16e/m and 3GPP Long Term Evolution (LTE), require significantly large signaling overhead for delivering small-sized delay-sensitive traffic such as voice over IP (VoIP) service. It may result in a significant decrease in the spectral efficiency. In order to overcome this drawback, recently, a persistent scheduling scheme has been standardized in standard bodies. In order to reduce the signaling overhead, the modulation and coding scheme (MCS) is set to be fixed during a burst period for the persistent scheduling procedure and an incomplete transmission, if it occurs, is recovered by a hybrid automatic repeat request (HARQ) scheme. In this paper, considering the HARQ retransmissions, we propose a rate selection scheme for the persistent scheduling satisfying given quality of service (QoS) requirements. In our proposed rate selection scheme, we consider two important factors which were not considered in previous HARQ-related work: time-correlations of the wireless channel in the HARQ retransmissions and the resource usage of signaling overhead. Numerical results show that the proposed rate selection scheme can efficiently enhance the utilization of radio resources compared to the conventional schemes.</P>