Nuclear Magnetic Resonance based Characterization of the Protein Binding Pocket using Hyperpolarized Ligand

In the drug design process, the structural determination of the protein-ligand binding interface and understanding how the drug binds to the target protein at the protein binding pocket is essential. In the past few years, Dynamic Nuclear Polarization (DNP) combined with Nuclear Magnetic Resonance (NMR) has emerged as a new tool for studying interactions between different molecules. In this study, the DNP-NMR technique was employed for characterization of the protein binding pocket through binding of the hyperpolarized ligand to the protein. Trypsin and benzamidine were chosen as models for the protein and the ligand because the binding of benzamidine to trypsin is well-known. Several enhanced NMR signals of trypsin appeared from the binding of hyperpolarized benzamidine to trypsin. A significant finding was that those trypsin signals were non-uniformly enhanced when compared with the trypsin signals in the conventional (non-hyperpolarized) NMR spectrum, suggesting that a specific region of the protein, most likely the protein-binding pocket proximal to the bound hyperpolarized ligand, is selectively polarized. The polarization transfer process was described mathematically by fitting model equations to the enhanced signal intensities of both the protein and the ligand. A fit parameter was evaluated, which assuming the presence of a single spin on protein and ligand can be interpreted as a cross-relaxation rate (σ_(DNP)), that can provide spatial information between the two spins. Saturation Transfer Difference (STD)-NMR was employed as an independent method to measure the protein-ligand interaction. The fit parameters in the STD-NMR equations, the dissociation constant (K_(D)) and a cross-relaxation rate (σ_(STD)), were evaluated. KD determined from STD-NMR was consistent with the K_(D) values reported in the literatures, suggesting that STD-NMR data is reliable. σ_(STD) evaluated from STD-NMR was compared with σ_(DNP) evaluated from the DNP-NMR and found to be similar in magnitude

ミャンマー語テキストの形式手法による音節分割、正規化と辞書順排列

国立大学法人長岡技術科学大

Comparison of Social Networks, Perceived Risk and HIV Risk Behaviors between Older and Younger African Americans Living in High HIV Prevalence Zip Codes of Atlanta, Georgia

The prevalence of HIV/AIDS in the United States is still high despite advances in prevention and therapies. Among all races and ethnic groups, African Americans are the most severely affected and face a disproportionate burden. African Americans account for a higher proportion of HIV infections and deaths than other races and ethnicities. In addition, one of the fastest growing segments of AIDS cases is patients more than 50 years of age. This segment receives little attention concerning HIV infection and as the U.S. population continues to age, it is important to be aware of specific HIV-related risks faced by these older African Americans and to ensure that they get information and services to help protect them from infection. This study aims to understand and compare the social network characteristics, perceived risk of getting HIV infection and HIV risk behaviors between younger (18 to 49 years of age) and older (50 plus years of age) African Americans living in high HIV prevalence zip codes of Atlanta, Georgia. The study population included 897 African Americans. Controlling for socio-demographic variables, multivariate analyses revealed that older African Americans have significant higher proportion of injection drug use, are less likely to get tested for HIV and more likely to have a risky sex partner (i.e., exchange sex for money or drugs); however, older African Americans were less likely to engage in sexual risk behaviors. Groups did not differ in terms of their perceived risk for HIV and social network characteristics. More research is necessary to understand their HIV-related risk behaviors, both sexual and drug use, and the specific needs for primary prevention effort of HIV/AIDS transmission among older African Americans

5G無線通信における誤り訂正符号化方式の評価に関する研究

早大学位記番号:新8267早稲田大

Modelling of Sunshine Duration for Peninsular Malaysia

Knowledge of solar radiation at any area is important for designing solar energy conversion systems, and is also useful for ecophysiological studies. In the present study, we have analysed the daily sunshine duration records for Peninsular Malaysia and apply them in solar radiation modelling. Firstly, we fitted Angstrom type equation to solar radiation and sunshine duration, to deter mine the relation between them. We have found that the seasonal variations of the regression parameters, are different for even two nearby locations. Variation of solar radiation within a small area are also noticable. Secondly, we have studied on the probability distribution nature of daily relative sunshine duration. Daily relative sunshine duration data are fitted to three models. Parameters of the models are estimated only from the monthly mean. Kolmogorov-Smirnov test is applied to determine the goodness of fit. We have found that the four stations can model led by two distributions. Data are also fitted to well known beta distribution model. The effect of variance is also presented. Finally, time series analysis of daily relative sunshine duration data are presented in chapter 4. Using gaussian mapping technique, nonstationary and non-normal distribution nature of the sunshine can be transformed into stationary and normal distribution. The autocorrelation function and partial autocorrelation function show the characteristics of autoregressive process. Results from the Box-Pierce and Ljung-Box statistics indicate that the first order autoregressive model is not suitable, while the second order autoregressive model gives satisfactory results. The relative sunshine duration of any day is dependent on the previous two days

Synthesis, Characterization And Co2 Adsorption Of Caco3, Ca(Oh)2 And Inert Materials Incorporated Ca(Oh)2

Calcium oxide (CaO) based materials have been proposed as potential candidates for CO2 adsorption to reduce the emission of carbon dioxide (CO2) into the atmosphere especially from the combustion of fossil fuel power plants. In this research, aragonite (CaCO3), calcite (CaCO3), calcium hydroxide (Ca(OH)2) and inert materials incorporated calcium hydroxide (Ca(OH)2) were synthesized by hydrothermal, sol-gel assisted hydrothermal and precipitation methods, respectively. Various parameters such as hydrothermal temperature (8 h - 72 h), addition of polyacrylamide (PAM), sodium hydroxide (NaOH) concentration (2 M - 10 M), cetyltrimethyl ammonium bromide (CTAB) concentration (0.2 M - 0.9 M) and different inert incorporated materials (Mg, Zr, Ce and (Zr-Ce)) on as-synthesized samples were characterized. And then, the CO2 adsorption performances of calcium oxide (CaO) based adsorbents derived from as-synthesized samples were investigated. In the case of hydrothermal method, 1D aragonite (CaCO3) nanorods are observed at 72 h hydrothermal reaction time when PAM is used as an additive, whereas 1D aragonite nanorods are obtained without using PAM at 12 h reaction time. In sol-gel assistance hydrothermal method, 3D calcite (CaCO3) hollow microspheres are attained with 2 M of NaOH concentration, while nanostructured calcium hydroxide (Ca(OH)2) is obtained by precipitation method at high CTAB concentration of 0.9 M. On the other hand, Mg, Zr, Ce and (Zr-Ce) incorporated Ca(OH)2 samples exhibit different surface morphologies. The CO2 adsorption capacities of calcium oxide (CaO) derived from 1D aragonite CaCO3 nanorods, 3D calcite CaCO3 hollow microspheres and nanostructured calcium hydroxide Ca(OH)2 after first cycles are 0.80 g-CO2/g-adsorbent, 0.62 g-CO2/g-adsorbent and 0.71 g-CO2/g-adsorbent, respectively. However, these capacities drop to 0.38 g-CO2/g-adsorbent, 0.39 g-CO2/g-adsorbent and 0.48 g-CO2/g-adsorbent after 10 cycles, respectively. It can be seen that CaO derived from Ca(OH)2 with surface area 64.57 m2/g exhibits the best CO2 adsorption capacity after 10 cycles (0.48 g-CO2/g-adsorbent), but the decay in adsorption capacity with number of cycles is observed. The development of cyclic stability can be observed in CaO-based adsorbents derived from Mg, Zr, Ce and (Zr-Ce) incorporated Ca(OH)2 samples. The CaO-based adsorbent derived from Mg-Ca(OH)2 shows slightly decrease in capacity from 0.67 g-CO2/g-adsorbent after first cycle to 0.57 g-CO2/g-adsorbent after 10 cycles, while CaO-based adsorbents produced from Zr and Ce-incorporated Ca(OH)2 samples exhibit the obvious cyclic stability during 10 cycles, 0.38 g-CO2/g-adsorbent and 0.24 g-CO2/g-adsorbent, respectively. The CaO-based adsorbent derived from (Zr-Ce) acetates incorporated Ca(OH)2 sample increases the capacity from 0.59 g-CO2/g-adsorbent after first cycle to 0.63 g-CO2/g-adsorbent after 10 cycles. The higher adsorption capacity and better cyclic stability during 10 cycles are attributed to the high BET surface area (155.80 m2/g), a wide range of micro/mesopore size distribution (1.7 nm - 30 nm) and the presence of high temperature sintering resistance Ce2Zr3O10 compound