Rapid and Simple Method for the Determination in Sialic Acid of Yak Milk Fat Globule Membrane

Dehai Li 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.5

A rapid and simple method for the determination of sialic acid (Neu5Ac) of yak milk fat globule membrane (MFGM) by HPLC with a diode array detector was developed and validated. Samples were cleaned up just by hydrolysis and derivatization before HPLC analysis. Separation was achieved with an Agilent TC-C18 column. The method showed a good linearity (r=0.997), the sensitivity results showed that the limits of detection and limits of quantification for sialic acid were 10.0 and 21.0 μg/mL,respectively. The recovery of Neu5Ac was 95-97%. The method proved very simple and rapid for Neu5Ac analysis since separation was completely achieved at 12 min.

Systematic influence of different building spacing, height and layout on mean wind and turbulent characteristics within and over urban building arrays

Dehai Jiang,Weimei Jiang,Hongnian Liu,Jianning Sun 한국풍공학회 2008 Wind and Structures, An International Journal (WAS Vol.11 No.4

Large eddy simulations have been performed within and over different types of urban building arrays. This paper adopted three dimensionless parameters, building frontal area density (λf), the variation degree of building height (σh), and the staggered degree of building range (rs), to study the systematic influence of building spacing, height and layout on wind and turbulent characteristics. The following results have been achieved: (1) As λf decrease from 0.25 to 0.18, the mean flow patterns transfer from “skimming” flow to “wake interference” flow, and as λf decrease from 0.06 to 0.04, the mean flow patterns transfer from “wake interference” flow to “isolated roughness” flow. With increasing σh, wind velocity within arrays increases, and the vortexes in front of low buildings would break, even disappear, whereas the vortexes in front of tall buildings would strengthen and expand. Tall buildings have greater disturbance on wind than low buildings do. (2) All the wind velocity profiles and the upstream profile converge at the height of 2.5H approximately. The decay of wind velocity within the building canopy was in positive correlation with λf and rs. If the height of building arrays is variable, Macdonald’s wind velocity model should be modified through introducing σh, because wind velocity decreases at the upper layers of the canopy and increases at the lower layers of the canopy. (3) The maximum of turbulence kinetic energy (TKE) always locates at 1.2 times as high as the buildings. TKE within the canopy decreases with increasing λf and rs but the maximum of TKE are very close though σh varies. (4) Wind velocity profile follows the logarithmic law approximately above the building canopy. The Zero-plane displacement zd heighten with increasing λf, whereas the maximum of and Roughness length z0 occurs when λf is about 0.14. zd and z0 heighten linearly with σh and rs, If σh is large enough, zd may become higher than the average height of buildings.

The Optimization Algorithm for the Pathfinder Sea Surface Temperature in the East China Seas

Dehai Song,Xianwen Bao,Xiao Hua Wang,Wen Wu 한국해양과학기술원 2009 Ocean science journal Vol.44 No.1

Based on the analysis of the quality level in a Pathfinder 4km daily nighttime Sea Surface Temperature product (PFSST) in the East China Seas (ECS) from 1985 to 2004, the proportion of high-quality data was lower than that in the global level. Additionally, the PFSST maps showed clearly the void and anomaly data impacted by atmospheric contamination. In order to solve the above problem, an optimal algorithm was established through introducing the structure function, setting up the daily first-guess sea surface temperature (SST) field and taking PFSST product of the highest quality as reference points. Comparisons were done between this optimally interpolated SST and the selected original PFSST and the simultaneous in situ measurements. It illustrated it was possible to exactly estimate the SST values in the ECS during the recent two decades. The mean bias error and the root mean square error between data sets optimally evaluated and in situ observed were lower than those between the previous global estimations and in situ measurnments. Based on the analysis of the quality level in a Pathfinder 4km daily nighttime Sea Surface Temperature product (PFSST) in the East China Seas (ECS) from 1985 to 2004, the proportion of high-quality data was lower than that in the global level. Additionally, the PFSST maps showed clearly the void and anomaly data impacted by atmospheric contamination. In order to solve the above problem, an optimal algorithm was established through introducing the structure function, setting up the daily first-guess sea surface temperature (SST) field and taking PFSST product of the highest quality as reference points. Comparisons were done between this optimally interpolated SST and the selected original PFSST and the simultaneous in situ measurements. It illustrated it was possible to exactly estimate the SST values in the ECS during the recent two decades. The mean bias error and the root mean square error between data sets optimally evaluated and in situ observed were lower than those between the previous global estimations and in situ measurnments.

Cell Division Cycle Associated 8 Is a Key Regulator of Tamoxifen Resistance in Breast Cancer

Dehai Yu,Libo Shi,Yuhui Bu,Weidong Li 한국유방암학회 2019 Journal of breast cancer Vol.22 No.2

Purpose: Breast cancer (BC) is one of the most common malignancies globally, and millions of women worldwide are diagnosed with BC every year. Up to 70% of BC patients are estrogen receptor (ER)-positive. Numerous studies have shown that tamoxifen has a significant therapeutic effect on both primary and metastatic ER-positive BC patients. Although tamoxifen is currently one of the most successful therapeutic agents for BC, a significant proportion of patients will eventually become resistant to tamoxifen, leading to tumor recurrence and metastasis. Knowledge about the development of tamoxifen resistance in BC patients is still limited. Methods: We applied a loss-and-gain method to study the biological functional role of cell division cycle associated 8 (CDCA8) in tamoxifen resistance in BC cells. Results: We found that CDCA8 was significantly elevated in tamoxifen-resistant BC cells. Knockdown of CDCA8 expression significantly inhibited the proliferation of tamoxifen-resistant BC cells and reduced their resistance to tamoxifen. In contrast, overexpression of CDCA8 promoted the growth of tamoxifen-sensitive BC cells and induced their resistance to tamoxifen. Conclusion: In this study, we reported that CDCA8 is a key regulator of tamoxifen resistance in BC, suggesting that CDCA8 may serve as a potential therapeutic target for BC treatment.

A New Cytotoxic Phenazine Derivative from a Deep Sea Bacterium Bacillus sp.

Dehai Li,Fengping Wang,Xiang Xiao,Xiang Zeng,Qian-Qun Gu,Weiming Zhu 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.5

A novel phenazine derivative (1) together with six known compounds (2-7) were isolated by bioassay-guided fractionation from the culture broth of a bacterium, Bacillus sp., collected from a Pacific deep sea sediment sample (depth 5059 m). The structures of these compounds were determined using spectroscopic methods. Their cytotoxic effects on P388 and K562 cell lines were preliminarily examined using the sulforhodamine-B (SRB) assay.

Systematic influence of different building spacing, height and layout on mean wind and turbulent characteristics within and over urban building arrays

Jiang, Dehai,Jiang, Weimei,Liu, Hongnian,Sun, Jianning Techno-Press 2008 Wind and Structures, An International Journal (WAS Vol.11 No.4

Large eddy simulations have been performed within and over different types of urban building arrays. This paper adopted three dimensionless parameters, building frontal area density (${\lambda}_f$) the variation degree of building height (${\sigma}_h$), and the staggered degree of building range ($r_s$), to study the systematic influence of building spacing, height and layout on wind and turbulent characteristics. The following results have been achieved: (1) As ${\lambda}_f$ decrease from 0.25 to 0.18, the mean flow patterns transfer from "skimming" flow to "wake interference" flow, and as ${\lambda}_f$ decrease from 0.06 to 0.04, the mean flow patterns transfer from "wake interference" flow to "isolated roughness" flow. With increasing ${\lambda}_f$, wind velocity within arrays increases, and the vortexes in front of low buildings would break, even disappear, whereas the vortexes in front of tall buildings would strengthen and expand. Tall buildings have greater disturbance on wind than low buildings do. (2) All the wind velocity profiles and the upstream profile converge at the height of 2.5H approximately. The decay of wind velocity within the building canopy was in positive correlation with ${\lambda}_f$ and $r_s$. If the height of building arrays is variable, Macdonald's wind velocity model should be modified through introducing ${\sigma}_h$, because wind velocity decreases at the upper layers of the canopy and increases at the lower layers of the canopy. (3) The maximum of turbulence kinetic energy (TKE) always locates at 1.2 times as high as the buildings. TKE within the canopy decreases with increasing ${\lambda}_f$ and $r_s$ but the maximum of TKE are very close though ${\sigma}_h$ varies. (4) Wind velocity profile follows the logarithmic law approximately above the building canopy. The Zero-plane displacement $z_d$ heighten with increasing ${\lambda}_f$, whereas the maximum of and Roughness length $z_0$ occurs when ${\lambda}_f$ is about 0.14. $z_d$ and $z_0$ heighten linearly with ${\sigma}_h$ and $r_s$, If ${\sigma}_h$ is large enough, $z_d$ may become higher than the average height of buildings.

The Optimization Algorithm for the Pathfinder Sea Surface Temperature in the East China Seas

Song, Dehai,Bao, Xianwen,Wang, Xiao Hua,Wu, Wen 한국해양학회 2009 Ocean science journal Vol.44 No.1

Based on the analysis of the quality level in a Pathfinder 4km daily nighttime Sea Surface Temperature product (PFSST) in the East China Seas (ECS) from 1985 to 2004, the proportion of high-quality data was lower than that in the global level. Additionally, the PFSST maps showed clearly the void and anomaly data impacted by atmospheric contamination. In order to solve the above problem, an optimal algorithm was established through introducing the structure function, setting up the daily first-guess sea surface temperature (SST) field and taking PFSST product of the highest quality as reference points. Comparisons were done between this optimally interpolated SST and the selected original PFSST and the simultaneous in situ measurements. It illustrated it was possible to exactly estimate the SST values in the ECS during the recent two decades. The mean bias error and the root mean square error between data sets optimally evaluated and in situ observed were lower than those between the previous global estimations and in situ measurnments.

Formulation of a rational dosage regimen of ceftiofur hydrochloride oily suspension by pharmacokinetic-pharmacodynamic (PK-PD) model for treatment of swine Streptococcus suis infection

Wanhe Luo,Dehai Wang,Hua Qin,Dongmei Chen,Yuanhu Pan,Wei Qu,Lingli Huang,Shuyu Xie 대한수의학회 2021 Journal of Veterinary Science Vol.22 No.6

Background: Our previously prepared ceftiofur (CEF) hydrochloride oily suspension shows potential wide applications for controlling swine Streptococcus suis infections, while the irrational dose has not been formulated. Objectives: The rational dose regimens of CEF oily suspension against S. suis were systematically studied using a pharmacokinetic-pharmacodynamic model method. Methods: The healthy and infected pigs were intramuscularly administered CEF hydrochloride oily suspension at a single dose of 5 mg/kg, and then the plasma and pulmonary epithelial lining fluid (PELF) were collected at different times. The minimum inhibitory concentration (MIC), minimal bactericidal concentration, mutant prevention concentration (MPC), post-antibiotic effect (PAE), and time-killing curves were determined. Subsequently, the area under the curve by the MIC (AUC0–24h/MIC) values of desfuroylceftiofur (DFC) in the PELF was obtained by integrating in vivo pharmacokinetic data of the infected pigs and ex vivo pharmacodynamic data using the sigmoid Emax (Hill) equation. The dose was calculated based on the AUC0–24h/MIC values for bacteriostatic action, bactericidal action, and bacterial elimination. Results: The peak concentration, the area under the concentration-time curve, and the time to peak for PELF's DFC were 24.76 ± 0.92 μg/mL, 811.99 ± 54.70 μg·h/mL, and 8.00 h in healthy pigs, and 33.04 ± 0.99 μg/mL, 735.85 ± 26.20 μg·h/mL, and 8.00 h in infected pigs, respectively. The MIC of PELF's DFC against S. suis strain was 0.25 μg/mL. There was strong concentration-dependent activity as determined by MPC, PAE, and the time-killing curves. The AUC0–24h/MIC values of PELF's DFC for bacteriostatic activity, bactericidal activity, and virtual eradication of bacteria were 6.54 h, 9.69 h, and 11.49 h, respectively. Thus, a dosage regimen of 1.94 mg/kg every 72 h could be sufficient to reach bactericidal activity. Conclusions: A rational dosage regimen was recommended, and it could assist in increasing the treatment effectiveness of CEF hydrochloride oily suspension against S. Suis infections.

Two Indolocarbazole Alkaloids with Apoptosis Activity from a Marine-derived Actinomycete Z2039-2

Rui Liu,Tianjiao Zhu,Dehai Li,Jingyan Gu,Wei Xia,Yuchun Fang,HongbingLiu,Weiming Zhu,Qianqun Gu 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.3

Bioassay-guided fractionation of the EtOAc extract from the fermentation broth of a marinederived actinomycete Z2039-2 led to the isolation of two known indolocarbazole alkaloids, K252c (1) and arcyriaflavin A (2). 1 and 2 exhibited moderate cytotoxic activities against the K562 cell line, and induced apoptotic activities at 10 and 100 µM, respectively. This is the first report on the significant apoptosis inducing effect of indolocarbazole alkaloids against K562 cancer cells.

Expediting the Formation of Cellulose Nanopaper by Heterocoagulation of Oppositely Charged Cellulose Nanofibers

Meng Kang,Chenglong Li,Dehai Yu,Guodong Li,Zhaoping Song,Huili Wang,Wenxia Liu 한국섬유공학회 2022 Fibers and polymers Vol.23 No.7

Cellulose nanopaper has attracted tremendous attention as an alternative to fossil-based flexible substrates. However, the fabrication of nanopaper from cellulose nanofibers (CNFs) is a time-consuming process. Herein, positivelycharged CNFs (PCNFs) were employed to heterocoagulate negatively charged CNFs (NCNFs) at various PCNF-to-NCNFratios in order to decrease the formation time of nanopaper. At a PCNF-to-NCNF ratio of 1:1, the formation time was reducedfrom 98 min to 20 min. Although heterocoagulation increases the roughness of cellulose nanopaper, nanopapers made from amixture of NCNFs and PCNFs still possess a nanosized network structure and therefore show similar transparency tonanopapers made of pure NCNFs. Compared to the nanopaper made from pure NCNFs, the nanopaper made from themixture of NCNFs and PCNFs showed reduced tensile strength but improved resistance to deformation. This study providesa practical method for the production of cellulose nanopaper.