372 research outputs found
Study Design for the 2016 Baseline Survey of a Health System Strengthening Project in Quoc Oai District, Hanoi, Vietnam
No full textBackground: In order to provide essential scientific evidence on the population's health status and social health determinants as well as the current capacity of the health care system in Vietnam to health policy makers and managers, Vietnam Ministry of Health, Hanoi University of Public Health, Hanoi Medical University, and Ho Chi Minh University of Medicine and Pharmacy collaborated with Seoul National University (Korea) and conducted a health system survey in the Quoc Oai district (of Hanoi capital) that represented northern rural Vietnam. Methods: The study design was a cross-sectional study. The survey covered different topics (more than 200 questions) and was administered in three separate questionnaires: 1) Basic information of all household members; 2) Household characteristics; and 3) Individual characteristics. Socio-demographic characteristics among the households and individuals were collected from 2,400 households sampled by multi-stage cluster sampling method: more than 200 questions. Results: The household size of Quoc Oai was larger than the national average and there was no significant difference in gender composition. In addition, the proportions of pre-elderly, age 55-64, and elderly group (65 years old and over) were higher than the national population statistics. In this context, demographic transition has begun in Quoc Oai. Conclusion: This study design description provides the basic information about a baseline survey of a future prospective cohort (as a part of a collaborative project on strengthening the health system in Vietnam) to the prospective data user of this survey.Full Tex
Rheological studies of municipal sewage sludge slurries for hydrothermal liquefaction biorefinery applications
No full textAbstract not available.Sylvia Y. Edifor, Quoc D. Nguyen, Philip van Eyk, Patrick Biller, David M. Lewi
Land-tenure policy reforms: Decollectivization and the Doi Moi system in Vietnam
Get PDFmillions fed, food security, rice, Land tenure, Land reform, Doi Moi, Decollectivization,
Discovery and characterization of an F420-dependent glucose-6-phosphate dehydrogenase (Rh-FGD1) from Rhodococcus jostii RHA1
Get PDFCofactor F420, a 5-deazaflavin involved in obligatory hydride transfer, is widely distributed among archaeal methanogens and actinomycetes. Owing to the low redox potential of the cofactor, F420-dependent enzymes play a pivotal role in central catabolic pathways and xenobiotic degradation processes in these organisms. A physiologically essential deazaflavoenzyme is the F420-dependent glucose-6-phosphate dehydrogenase (FGD), which catalyzes the reaction F420 + glucose-6-phosphate → F420H2 + 6-phospho-gluconolactone. Thereby, FGDs generate the reduced F420 cofactor required for numerous F420H2-dependent reductases, involved e.g., in the bioreductive activation of the antitubercular prodrugs pretomanid and delamanid. We report here the identification, production, and characterization of three FGDs from Rhodococcus jostii RHA1 (Rh-FGDs), being the first experimental evidence of F420-dependent enzymes in this bacterium. The crystal structure of Rh-FGD1 has also been determined at 1.5 Å resolution, showing a high similarity with FGD from Mycobacterium tuberculosis (Mtb) (Mtb-FGD1). The cofactor-binding pocket and active-site catalytic residues are largely conserved in Rh-FGD1 compared with Mtb-FGD1, except for an extremely flexible insertion region capping the active site at the C-terminal end of the TIM-barrel, which also markedly differs from other structurally related proteins. The role of the three positively charged residues (Lys197, Lys258, and Arg282) constituting the binding site of the substrate phosphate moiety was experimentally corroborated by means of mutagenesis study. The biochemical and structural data presented here provide the first step towards tailoring Rh-FGD1 into a more economical biocatalyst, e.g., an F420-dependent glucose dehydrogenase that requires a cheaper cosubstrate and can better match the demands for the growing applications of F420H2-dependent reductases in industry and bioremediation
Endurance enhancement of aerial vehicle energy transmitters using conical corrugated horn antenna
No full textA corrugated horn antenna is proposed for the unmanned aerial vehicle energy transmitter (UAVET) application. Firstly, the proposed antenna can be manufactured using polylactic acid (PLA) 3-dimensional (3-D) printing with copper conductive paint coating, which is lightweight and cost-effective compared to metal 3-D printing. Secondly, the results confirm that the sidelobe level of the antenna is below -30 dB, and radiation efficiency is above 99 % throughout the operating frequency band. Also, the proposed antenna increases the UAV-ET wireless power transfer (WPT) time by 47.5 % and 4.5 % compared to UAVETs equipped with a dipole array and a slotted waveguide array respectively. Furthermore, the mass production of the antenna is easy because of its design simplicity which is highly desirable for the large swarm of UAV-ETs to increase the wireless power transfer coverage for charging ground sensors
WHO's service availability and readiness assessment of primary health care services of commune health centers in a rural district of Northern Vietnam
Get PDFThe objective of this study was to assess the availability and readiness of the primary health care (PHC) services of commune health centers (CHCs) in Quoc Oai, a rural district of Northern Vietnam based on the World Health Organization's Service Availability and Readiness Assessment (SARA) tool. The study was done in 2 steps. First, the heads of the 21 CHCs of Quoc Oai district were interviewed using SARA, a quantitative survey, and the responses were then validated by direct observations of each facility. The results showed that although the average number of health staffs in each CHC met the national standards (at least 5 staffs per CHC), its allocation within each CHC was not properly met because some CHCs had only 2 health staffs. Several health equipment and facilities were not fully available in many CHCs, and although the majority of the PHC services were available at the CHCs, their readiness remained limited. Several significant correlates between the availability of health care workers and the availability of the facilities and the PHC services were observed, suggesting that they depend upon and affect one another in the health system. Using the SARA-based inventory, the study helps health managers and policy makers to prioritize efforts and allocate resources more appropriately. To be effective, attention should be given to how to make facilities, services, and human resources for health ready for PHC activities—more investment and support from the system (from higher to lower level) and the government. Copyright © 2017 John Wiley & Sons, Ltd
Recommended from our members
An investigation into surfactant stabilized, non-aqueous and semi-aqueous foam for enhanced oil recovery
Get PDFFoam serves as an important role in enhanced oil recovery processes involving gas injection since it hinders flow and acts as a mobility control agent. Significant work has been presented for the utilization of water as the continuous, external phase of the foam, but opportunity exists in using a non-aqueous compound instead.
Y-grade, a raw blend of NGLs, has been becoming more available with the increase in wet gas, shale plays over the last decade. Coinjecting or alternating the injection of nitrogen and y-grade with a foam stabilizing additive, such as a surfactant, may provide a recovery scheme with both a strong displacement efficiency due to the miscible nature of the y-grade with oil and a strong sweep efficiency due to the mobility control provided by the y-grade-based foam.
The foaming ability of y-grade was investigated by using pentane as a stand-in since it is the lightest alkane that is still readily a liquid at room conditions. Thirty-eight additives spanning a wide range of chemical properties were evaluated for their potential to generate and stabilize the non-aqueous foam. In addition, both water and non-aqueous liquids were investigated to see if they would increase the foaming potential of the y-grade or pentane by being mixed as a secondary component.
Concurrently, a procedure and experimental assembly was created to blend a synthetic y-grade containing ethane through octane. This synthetic y-grade was used to validate the assumptions made in the pentane screening tests by further blending in nitrogen, water, and other additives into pressurized visual cells for observation. In addition, the y-grade was used in a coreflood as a base case for a planned series of tests for y-grade-based foam within a porous media for oil recovery purposes.Petroleum and Geosystems Engineerin
Environmental impact assessment of the pangasius sector in the Mekong Delta
No full textIn the past seven years the export of white pangasius fillets grew fast. The culture method shifted to intensive production of striped catfish (Ca Tra) in deep ponds because this is more efficient than the pen and cage culture of Ca Basa. Today, striped catfish comprises more than 90 % of the culture. The increased production was achieved by producers investing in large ponds. The market chain is gearing towards vertical integration. Most farms keep fish at relatively high densities of 15 to 25 fish/m3 in ponds having a depth of up to 4m, and are advised to exchange daily 20 to 40% of the water. The sustainability of the sector is threatened due to the increased environmental pressure, and hampered by the growing cost of inputs and reduced farm-gate prices of the fish. The Environmental Impact Assessment (EIA) intends to identify measures for preventing or mitigating the environmental impacts of catfish culture in the Mekong Delta. The EIA was a seven-step process during which we interacted twice with part of the main stakeholders. To build trust among the stakeholders from the sector, we conducted the scoping and goal setting with them
Potential theory for nonlocal drift-diffusion equations
No full textNguyen Q-H, Nowak SN, Sire Y, Weidner M. Potential theory for nonlocal drift-diffusion equations. Archive for Rational Mechanics and Analysis. 2024;248(6):1-42.The purpose of this paper is to prove new fine regularity results for nonlocal drift-diffusion equations via pointwise potential estimates. Our analysis requires only minimal assumptions on the divergence free drift term, enabling us to include drifts of critical order belonging merely to BMO. In particular, our results allow to derive new estimates for the dissipative surface quasi-geostrophic equation
Current rectification by nanoparticle blocking in single cylindrical nanopores
Get PDFBlocking of a charged pore by an oppositely charged nanoparticle can support rectifying properties in a cylindrical nanopore, as opposed to the usual case of a fixed asymmetry in the pore geometry and charge distribution. We present here experimental data and model calculations to confirm this fundamental effect. The nanostructure imaging and the effects of nanoparticle concentration, pore radius, and salt concentration on the electrical conductance–voltage (G–V) curves are discussed. Logic responses based on chemical and electrical inputs/outputs could also be implemented with a single pore acting as an effective nanofluidic diode. To better show the generality of the results, different charge states and relative sizes of the nanopore and the nanoparticle are considered, emphasizing those physical concepts that are also found in the ionic drug blocking of protein ion channels.M. A., S. N., Q.-H. N., and W. E. acknowledge the Beilstein-Institut, Frankfurt/Main, Germany, within the research collaboration NanoBiC. P. R. and S. M. acknowledge the Ministry of Economy and Competitiveness (project MAT2012-32084), FEDER, and Generalitat Valenciana (project PROMETEO/GV/0069). The authors thank Prof. Dr Christina Trautmann from GSI for support with the heavy ion irradiation experiments and an anonymous referee for helpful suggestions.Ali, M.; Ramirez Hoyos, P.; Nasir, S.; Nguyen, Q.; Ensinger, W.; Mafé, S. (2014). Current rectification by nanoparticle blocking in single cylindrical nanopores. Nanoscale. 6(18):10740-10745. https://doi.org/10.1039/c4nr02968bS1074010745618Vlassiouk, I., & Siwy, Z. S. (2007). Nanofluidic Diode. Nano Letters, 7(3), 552-556. doi:10.1021/nl062924bAli, M., Ramirez, P., Mafé, S., Neumann, R., & Ensinger, W. (2009). A pH-Tunable Nanofluidic Diode with a Broad Range of Rectifying Properties. ACS Nano, 3(3), 603-608. doi:10.1021/nn900039fCervera, J., Ramirez, P., Mafe, S., & Stroeve, P. (2011). Asymmetric nanopore rectification for ion pumping, electrical power generation, and information processing applications. Electrochimica Acta, 56(12), 4504-4511. doi:10.1016/j.electacta.2011.02.056Guo, W., Cao, L., Xia, J., Nie, F.-Q., Ma, W., Xue, J., … Jiang, L. (2010). Energy Harvesting with Single-Ion-Selective Nanopores: A Concentration-Gradient-Driven Nanofluidic Power Source. Advanced Functional Materials, 20(8), 1339-1344. doi:10.1002/adfm.200902312Nestorovich, E. M., Danelon, C., Winterhalter, M., & Bezrukov, S. M. (2002). Designed to penetrate: Time-resolved interaction of single antibiotic molecules with bacterial pores. Proceedings of the National Academy of Sciences, 99(15), 9789-9794. doi:10.1073/pnas.152206799Mafé, S., Ramı́rez, P., & Alcaraz, A. (2003). Simple molecular model for the binding of antibiotic molecules to bacterial ion channels. The Journal of Chemical Physics, 119(15), 8097-8102. doi:10.1063/1.1606438Karginov, V. A., Nestorovich, E. M., Moayeri, M., Leppla, S. H., & Bezrukov, S. M. (2005). Blocking anthrax lethal toxin at the protective antigen channel by using structure-inspired drug design. Proceedings of the National Academy of Sciences, 102(42), 15075-15080. doi:10.1073/pnas.0507488102Aguilella-Arzo, M., Cervera, J., Ramírez, P., & Mafé, S. (2006). Blocking of an ion channel by a highly charged drug: Modeling the effects of applied voltage, electrolyte concentration, and drug concentration. Physical Review E, 73(4). doi:10.1103/physreve.73.041914Yu Apel, P., Blonskaya, I. V., Orelovitch, O. L., Sartowska, B. A., & Spohr, R. (2012). Asymmetric ion track nanopores for sensor technology. Reconstruction of pore profile from conductometric measurements. Nanotechnology, 23(22), 225503. doi:10.1088/0957-4484/23/22/225503Ali, M., Ramirez, P., Nguyen, H. Q., Nasir, S., Cervera, J., Mafe, S., & Ensinger, W. (2012). Single Cigar-Shaped Nanopores Functionalized with Amphoteric Amino Acid Chains: Experimental and Theoretical Characterization. ACS Nano, 6(4), 3631-3640. doi:10.1021/nn3010119Lee, S., Zhang, Y., White, H. S., Harrell, C. C., & Martin, C. R. (2004). Electrophoretic Capture and Detection of Nanoparticles at the Opening of a Membrane Pore Using Scanning Electrochemical Microscopy. Analytical Chemistry, 76(20), 6108-6115. doi:10.1021/ac049147pDavenport, M., Healy, K., Pevarnik, M., Teslich, N., Cabrini, S., Morrison, A. P., … Létant, S. E. (2012). The Role of Pore Geometry in Single Nanoparticle Detection. ACS Nano, 6(9), 8366-8380. doi:10.1021/nn303126nMenestrina, J., Yang, C., Schiel, M., Vlassiouk, I., & Siwy, Z. S. (2014). Charged Particles Modulate Local Ionic Concentrations and Cause Formation of Positive Peaks in Resistive-Pulse-Based Detection. The Journal of Physical Chemistry C, 118(5), 2391-2398. doi:10.1021/jp412135vXia, T., Kovochich, M., Brant, J., Hotze, M., Sempf, J., Oberley, T., … Nel, A. E. (2006). Comparison of the Abilities of Ambient and Manufactured Nanoparticles To Induce Cellular Toxicity According to an Oxidative Stress Paradigm. Nano Letters, 6(8), 1794-1807. doi:10.1021/nl061025kRamirez, P., Gomez, V., Ali, M., Ensinger, W., & Mafe, S. (2013). Net currents obtained from zero-average potentials in single amphoteric nanopores. Electrochemistry Communications, 31, 137-140. doi:10.1016/j.elecom.2013.03.026Pellicer, J., Mafé, S., & Aguilella, V. M. (1986). Ionic Transport Across Porous Charged Membranes and the Goldman Constant Field Assumption. Berichte der Bunsengesellschaft für physikalische Chemie, 90(10), 867-872. doi:10.1002/bbpc.19860901008Wanunu, M., Morrison, W., Rabin, Y., Grosberg, A. Y., & Meller, A. (2009). Electrostatic focusing of unlabelled DNA into nanoscale pores using a salt gradient. Nature Nanotechnology, 5(2), 160-165. doi:10.1038/nnano.2009.379Macrae, M. X., Blake, S., Mayer, M., & Yang, J. (2010). Nanoscale Ionic Diodes with Tunable and Switchable Rectifying Behavior. Journal of the American Chemical Society, 132(6), 1766-1767. doi:10.1021/ja909876hTagliazucchi, M., Rabin, Y., & Szleifer, I. (2013). Transport Rectification in Nanopores with Outer Membranes Modified with Surface Charges and Polyelectrolytes. ACS Nano, 7(10), 9085-9097. doi:10.1021/nn403686sRamirez, P., Ali, M., Ensinger, W., & Mafe, S. (2012). Information processing with a single multifunctional nanofluidic diode. Applied Physics Letters, 101(13), 133108. doi:10.1063/1.4754845B. Hille , Ion Channels of Excitable Membranes , Sinauer , Sunderland , 1992Ali, M., Nasir, S., Ramirez, P., Cervera, J., Mafe, S., & Ensinger, W. (2013). Carbohydrate-Mediated Biomolecular Recognition and Gating of Synthetic Ion Channels. The Journal of Physical Chemistry C, 117(35), 18234-18242. doi:10.1021/jp4054555Ali, M., Ramirez, P., Nasir, S., Nguyen, Q.-H., Ensinger, W., & Mafe, S. (2014). Nanoparticle-induced rectification in a single cylindrical nanopore: Net currents from zero time-average potentials. Applied Physics Letters, 104(4), 043703. doi:10.1063/1.486351
- …
