A facile and reliable route to prepare highly dispersive ammonium dimolybdate uniform crystals from commercial molybdenum oxide

Jun Zhang,Yanhui Guo,Weiwei Lu,Xuming Guo,Mingchen Xu,Hongbo Guo 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.5

Highly dispersive ammonium dimolybdate crystals with high purity have been prepared through reaction–evaporation–crystallization united route using commercial molybdenum oxide as starting material. The as-prepared ammonium dimolybdate uniform crystals were systematically characterized by X-ray powder diffraction, transmission-reflection optical microscope, Fourier transform infrared spectroscopy and TG-DSC thermal analysis. The Fsss grain diameter, loose packed density, and crystal-grain size distribution were also measured by the Malvern laser particle sizer. These collective characterization and analysis reveal that the ammonium dimolybdate grains are non-agglomerated uniform crystals with well normal distribution and geometric shape. The average Fsss diameter, d(0.5) and loose packed density are 433.316 mm, 470.981 mm and 1.592 g cm3, respectively, which could well meet the quality requirements for the subsequent production of molybdenum powders.

Study on Pollen Viability, Longevity and Pistil Receptivity of Self-Compatible Chrysanthemum with Small Inflorescences

Hongbo Zhao,Fadi Chen,Yanfang Wang,Weimin Fang,Sumei Chen,Weiming Guo 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

A novel class of pyranocoumarin anti-androgen receptor signaling compounds.

Guo, Junming,Jiang, Cheng,Wang, Zhe,Lee, Hyo-Jeong,Hu, Hongbo,Malewicz, Barbara,Lee, Hyo-Jung,Lee, Jae-Ho,Baek, Nam-In,Jeong, Jin-Hyun,Kim, Dae-Keun,Kang, Kyung-Sun,Kim, Sung-Hoon,Lu, Junxuan American Association for Cancer Research 2007 Molecular Cancer Therapeutics Vol.6 No.3

<P>Androgen and the androgen receptor (AR)-mediated signaling are crucial for prostate cancer development. Novel agents that can inhibit AR signaling in ligand-dependent and ligand-independent manners are desirable for the chemoprevention of prostate carcinogenesis and for the treatment of advanced prostate cancer. We have shown recently that the pyranocoumarin compound decursin from the herb Angelica gigas possesses potent anti-AR activities distinct from the anti-androgen bicalutamide. Here, we compared the anti-AR activities and the cell cycle arrest and apoptotic effects of decursin and two natural analogues in the androgen-dependent LNCaP human prostate cancer cell culture model to identify structure-activity relationships and mechanisms. Decursin and its isomer decursinol angelate decreased prostate-specific antigen expression with IC(50) of approximately 1 mumol/L. Both inhibited the androgen-stimulated AR nuclear translocation and transactivation, decreased AR protein abundance through proteasomal degradation, and induced G(0/1) arrest and morphologic differentiation. They also induced caspase-mediated apoptosis and reactive oxygen species at higher concentrations. Furthermore, they lacked the agonist activity of bicalutamide in the absence of androgen and were more potent than bicalutamide for suppressing androgen-stimulated cell growth. Decursinol, which does not contain a side chain, lacked the reactive oxygen species induction and apoptotic activities and exerted paradoxically an inhibitory and a stimulatory effect on AR signaling and cell growth. In conclusion, decursin and decursinol angelate are members of a novel class of nonsteroidal compounds that exert a long-lasting inhibition of both ligand-dependent and ligand-independent AR signaling. The side chain is critical for sustaining the anti-AR activities and the growth arrest and apoptotic effects.</P>

Migratory Responses of Benthic Diatoms to Light and Temperature Monitored by Chlorophyll Fluorescence

Guo Ying Du,Wen Tao Li,Hongbo Li,정익교 한국식물학회 2012 Journal of Plant Biology Vol.55 No.2

As an important adaptation for survival in the sediments of intertidal flats, benthic diatoms move up and down in response to a wide range of environmental stimuli. We investigated the vertical migration of two diatoms—Cylindrotheca closterium (Agradh) Kützing (B-25) and Nitzschia sp. (B-3)—under different combinations of light intensity and temperature conditions. An imaging pulse amplitude modulated (PAM) fluorometer was used to measure the minimum fluorescence (F0) in order to monitor variations in diatom biomass in surface sediments. Rapid light curves (RLCs) were applied to assess their photosynthetic activities. Both species had increased motility under higher temperatures, with the longer valved C. closterium being twice as fast as the shorter valved Nitzschia sp. The former was also influenced by exposure to light intensities of 100 or 250 μmol m−2 s−1, whereas the latter was not. Consequently, no light/temperature interaction effect was associated with the vertical migration of Nitzschia sp., perhaps because of its lower photosynthetic capacity and smaller cell size. Therefore, we conclude that motile benthic diatoms exhibit species-specific responses to light and temperature due to differences in their photosynthetic capability and morphological characteristics.

A comparison of the fracture resistances of endodontically treated mandibular premolars restored with endocrowns and glass fiber post-core retained conventional crowns

Guo, Jing,Wang, Zhiming,Li, Xuesheng,Sun, Chaoyang,Gao, Erdong,Li, Hongbo The Korean Academy of Prosthodonitics 2016 The Journal of Advanced Prosthodontics Vol.8 No.6

PURPOSE. This in-vitro study aimed to evaluate the fracture resistances and failure modes of endodontically treated mandibular premolars restored with endocrowns and conventional post-core retained crowns. MATERIALS AND METHODS. Thirty mandibular premolars were assigned into three groups (n=10): GI, intact teeth; GE, teeth with endocrowns; GC, teeth with conventional post-core supported crowns. Except for the teeth in group GI, all specimens were cut to 1.5 mm above the cementoenamel junction and endodontically treated. Both endocrowns and conventional crowns were fabricated from lithium-disilicate blocks using a CEREC 3D CAD/CAM unit. All specimens were subjected to thermocycling and then to $45^{\circ}$ oblique compressive load until fracture occurred. The fracture resistance and failure mode of each specimen were recorded. Data were analyzed with one-way ANOVA and LSD Post Hoc Test (${\alpha}=.05$). RESULTS. The fracture resistances of GE and GC were significantly lower than that of GI (P<.01), while no significant difference was found between GE and GC (P=.702). As of the failure mode, most of the specimens in GE and GC were unfavorable while a higher occurrence of favorable failure mode was presented in GI. CONCLUSION. For the restoration of mandibular premolar, endocrown shows no advantage in fracture resistance when compared with the conventional method. Both of the two methods cannot rehabilitate endodontically treated teeth with the same fracture resistances that intact mandibular premolars have.

Research on the Influences of Time Harmonics on Permanent Magnet Synchronous Motors with Hybrid Magnet Poles

Hongbo Qiu,Yuedong Guo,Wenfei Yu,Bingxia Tang,Cunxiang Yang 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.3

With the development of electric electron technology and controlling technology, controller for driving permanent magnet synchronous motors is used widely. The using of a controller can expand the motor speed range and improve motor runtime performances. However, the output current of a controller contains lots of time harmonics that will have bad infl uences on motor torque and losses. In order to analyze the infl uences of the time harmonics on the motor performances, diff erent time harmonic currents were injected into the motor armature. Taking a 750 W, 250 r/min permanent magnet synchronous motor with hybrid magnet poles (HPPMSM) as an example, the 2-D fi nite model was established. On this basis, the torque ripple and eddy current losses of permanent magnets with diff erent time harmonics were obtained. The infl uences of time harmonics on motor torque ripple and eddy current losses were determined, and the impacting mechanism was revealed. The analyses may be helpful for the optimal design of HPPMSM.

Correction to: Research on the Infl uences of Time Harmonics on Permanent Magnet Synchronous Motors with Hybrid Magnet Poles

Hongbo Qiu,Yuedong Guo,Wenfei Yu,Bingxia Tang,Cunxiang Yang 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.4

Effect of Sodium Tripolyphosphate on Clay Tolerance of Polycarboxylate Superplasticizer

Hongbo Tan,Yulin Guo,Baoguo Ma,Jian Huang,Benqing Gu,Fubing Zou 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

High fluidity concrete has been widely used in modern civil engineering project to ensure that the highly efficient construction process canbe achieved. Generally, the fluidity can be obtained with the incorporation of superplasticizer system composed of polymers and retarders. Sodium tripolyphosphate (STPP), a commonly used retarder in cement-based material, can obviously increase the dispersion ofpolycarboxylate superplasticizer (PCE), and this has been widely employed in real concrete. However, the effect of STPP on clay toleranceof PCE has not been confirmed until now, and it is still uncertain whether STPP in PCE system has positive or negative effect on workabilityof fresh concrete with poor-quality aggregates containing montmorillonite (Mt) which is one of the most harmful clay minerals. In this study,the effect of STPP on fluidity of cement-Mt paste with PCE has been investigated. The fluidity was tested with mini slump to assess the claytolerance of PCE. The adsorption amount of PCE and STPP in Mt suspension was tested with total organic carbon analyzer and inductivecoupled plasma emission spectrometer to characterize the adsorption behavior. The interlayer spacing was evaluated with X-rayDiffractometer and the structure of intercalated Mt by PCE was characterized with Fourier-transform infrared spectrometer and thermogravimetric analyzer, and these results were used to illustrate the effect of STPP on intercalation of PCE. Finally, the dispersion model wasproposed to reveal the mechanism behind. The results show that STPP can disperse the Mt particles and increase adsorption amount of PCEin Mt suspension, thereby accelerating rather than hindering the intercalation of PCE into Mt. The fluidity of cement-Mt paste with PCESTPPsystem is depended on the added dosage of STPP: with the dosage less than 0.20%, the contribution of STPP to dispersing the cementparticles predominates, hence increasing the fluidity of the paste and improving the clay tolerance; while with the dosage more than 0.20%,the acceleration of the intercalation of PCE resulting from STPP becomes predominant, thereby reducing the fluidity of the paste. This resultcan provide useful experience for the improvement in clay tolerance of PCE in real concrete with poor aggregate containing Mt.

Re-SSS: Rebalancing Imbalanced Data Using Safe Sample Screening

( Hongbo Shi ),( Xin Chen ),( Min Guo ) 한국정보처리학회 2021 Journal of information processing systems Vol.17 No.1

Different samples can have different effects on learning support vector machine (SVM) classifiers. To rebalance an imbalanced dataset, it is reasonable to reduce non-informative samples and add informative samples for learning classifiers. Safe sample screening can identify a part of non-informative samples and retain informative samples. This study developed a resampling algorithm for Rebalancing imbalanced data using Safe Sample Screening (Re-SSS), which is composed of selecting Informative Samples (Re-SSS-IS) and rebalancing via a Weighted SMOTE (Re-SSS-WSMOTE). The Re-SSS-IS selects informative samples from the majority class, and determines a suitable regularization parameter for SVM, while the Re-SSS-WSMOTE generates informative minority samples. Both Re-SSS-IS and Re-SSS-WSMOTE are based on safe sampling screening. The experimental results show that Re-SSS can effectively improve the classification performance of imbalanced classification problems.

Effect of light and sediment grain size on the vertical migration of benthic diatoms

Guo Ying Du,옥정현,Hongbo Li,정익교 한국조류학회I 2010 ALGAE Vol.25 No.3

Using chlorophyll fluorescence, the vertical migration of benthic diatoms responding to light intensity and affected by sediment grain size was studied. Minimal fluorescence (Fo) of surface sediment was measured by imaging pulse amplitude modulated (Imaging-PAM) fluorometer, and used to monitor diatom biomass variation in surface sediments. The test diatoms, Amphora coffeaeformis (C. Agardh) Kützing and Cylindrotheca closterium (Ehrenberg) Reimann & Lewin,migrated to the sediment surface under irradiance from 50 to 500 μmol photons m-2 s-1. However, the diatoms exhibited no evident increase of surface biomass under dark conditions, and even showed slightly decrease of surface biomass under irradiances over 1,000 μmol photons m-2 s-1. The light intensity inducing the maximum surface migration of A. coffeaeformis was 100 μmol photons m-2 s-1, while the light intensity producing the same effect for C. closterium was 250μmol photons m-2 s-1. C. closterium showed higher motility than A. coffeaeformis. Faster diatom surfacing was observed in larger grain size sediments (125-335 μm) than smaller ones (63-125 μm). This study confirmed the significant influence of light as a main triggering factor behind migration, indicated the distinct effect of different sediment grain size,and highlighted the species-specific migratory ability.