The Viable But Nonculturable State of Kanagawa Positive and Negative Strains of Vibrio parahaemolyticus

Bates, Tonya C.,Oliver, James D. The Microbiological Society of Korea 2004 The journal of microbiology Vol.42 No.2

Ingestion of shellfish-associated Vibrio parahaemolyticus is the primary cause of potentially severe gas-troenteritis in many countries. However, only Kanagawa phenomenon (hemolysin) positive (KP$\^$+/) strains of V. parahaemolyticus are isolated from patients, whereas >99% of strains isolated from the environment do not produce this hemolysin (i.e. are KP$\^$-/). The reasons for these differences are not known. Following a temperature downshift, Vibrio parahaemolyticus enters the viable but noncultur-able (VBNC) state wherein cells maintain viability but cannot be cultured on routine microbiological media. We speculated that KP$\^$+/ and KP$\^$-/ strains may respond differently to the temperature and salinity conditions of seawater by entering into this state which might account for the low numbers of cul-turable KP$\^$+/ strains isolated from estuarine waters. The response of eleven KP$\^$+/ and KP$\^$-/ strains of V. parahaemolyticus following exposure to a nutrient and temperature downshift in different salinities, similar to conditions encountered in their environment, was examined. The strains included those from which the KP$\^$+/ genes had been selectively removed or added. Our results indicated that the ability to produce hemolysin did not affect entrance into the VBNC state. Further, VBNC cells of both biotypes could be restored to the culturable state following an overnight temperature upshift.

Simulation of an innovative polymer electrolyte membrane fuel cell design for self-control thermal management

Bates, A.,Hwang, S.,Mukherjee, S.,Lee, S.C.,Kwon, O.,Choi, G.H.,Park, S. Pergamon Press ; Elsevier Science Ltd 2013 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.38 No.20

Two novel fuel cell designs attempt to improve efficiency and reduce the balance of plant weight by implementing a square hole through the center of the bipolar plates. Air is forced through the square hole for the purpose of oxygen delivery, water removal, and stack cooling. This study demonstrates, for the two novel designs, a more even temperature distribution and hot spots away from the center of the bipolar plates. This reduces the number and size of components required to effectively run the system, thus reducing the weight of the balance of plant. Four simulations are presented in this paper, with inlet gases and initial cell temperature set to 333 K. The maximum temperature for case 1 without cooling is 347.97 K, case 1 with water cooling is 335.29 K, case 2 with forced air cooling is 339.42 K, and case 3 with forced air cooling is 335.13 K.

Economic Impact of the ASEAN Free Trade Agreement(AFTA) on Philippine Fruit Exports

Bates M. Bathana,Julieta A. Delos Reyesb 한국무역연구원 2015 무역연구 Vol.11 No.1

Banana, mango, and pineapple are the top fruit exports of the Philippines. These fruits,whether fresh or processed find their way to markets almost all over the world because ofthe country’s comparative advantage due to price and quality competitiveness relative toother exporters. However, the country’s competitiveness is threatened by the stringentsanitary and phytosanitary (SPS) measures implemented by some importing countries. Whilesuch fruits have been exported in the past decades, the economic impact of the country’saccession to the ASEAN Free Trade Agreement (AFTA), particularly on the volume of thesefruit exports, is yet to be known. Whether the country has benefitted from a commonmembership in the AFTA through increased exports to ASEAN member countries or thechanging trade patterns for these fruits due to the free trade agreement is worth lookinginto.Vital to the analysis also is the situation where the country is a member of the WorldTrade Organization (WTO) and that banana, mango, and pineapple are also produced andexported by some ASEAN member countries, thus complicating the issue of trade facilitationamong member countries. Secondary data on the volume of fresh banana, mango, and pineapple exports, includingtheir markets for the period covering 1990 to 2013 were collected and subjected todescriptive and multiple regression analyses which included a dummy variable for pre- andpost-AFTA periods. The AFTA dummy variable was found significant for banana and mango but not for pineapple. This suggests that the country’s accession to AFTA has increased itsexport of fresh banana and mango to ASEAN markets, particularly to Singapore, and to Japan,China and South Korea which are countries having trade agreements with ASEAN members.

Simulation and experimental analysis of the clamping pressure distribution in a PEM fuel cell stack

Bates, A.,Mukherjee, S.,Hwang, S.,Lee, S.C.,Kwon, O.,Choi, G.H.,Park, S. Pergamon Press ; Elsevier Science Ltd 2013 International journal of hydrogen energy Vol.38 No.15

High performance and efficiency are often reported in single-cell polymer electrolyte membrane (PEM) fuel cell (FC) experiments. This however, can reduce substantially when moving from single-cell experiments to multiple cells. Fuel cell performance is degraded for many reasons when adding cells, but; possibly the most important, is contact resistance between the bipolar plate and gas diffusion layer (GDL). Contact resistance is in direct relation to the clamping configuration and clamping pressure applied to a FC stack. Simulation of a single cell and 16-cell FC was performed at various clamping pressures resulting in detailed 3D plots of stress and deformation. The stress on the GDL, for any value of clamping pressure simulated in this study, is around 1.5 MPa for the 16-cell stack and around 4 MPa in single cell simulations. Experimental testing of clamping pressure effects was performed on a 16-cell stack by placing a thin pressure-sensitive film between GDL and bipolar plate. Clamping pressure was applied using various loads, durations, and two types of GDLs. The results from experimental testing show that pressure on the GDL is in the range of 0-2.5 MPa. When using rectangular cells, experimental results show nearly zero pressure in the center of each cell and the center cells of the stack, regardless of clamping method.

Analytical Study and Experimental Validation of Copper II Sulfate and Potassium Ferri/Ferrocyanide Thermocells Using Onsager Flux Equations

Bates, Alex M.,Zickel, Ben,Krebs, Steffen,Mukherjee, Santanu,Schuppert, Nicholas D.,Choi, Moon Jong,Park, Sam D. ASME International 2017 Journal of energy resources technology Vol.139 No.4

평준화인가 표준화인가? "유럽의 농약등록체계 통합"

Bates JAR 한국작물보호협회 1993 자연과 농업 Vol.14 No.2

Design and Simulation of Low Weight Fuel Cell Stack for a Mobile Robot Application

Alex Bates,SungMok Ha(하숭목),Sang C. Lee(이상철),Osung Kwon(권오성),Sam Park,Dong-Ha Lee(이동하) 한국태양에너지학회 2013 한국태양에너지학회 학술대회논문집 Vol.2013 No.4

Unmanned aerial vehicles (UAVs) are used for many purposes; however longer flight time and quiet operation are always desired. To achieve these two goals a light-weight open-cathode fuel cell is being developed. Longer flight times require either more fuel or a higher energy density fuel and the means to use it efficiently. Hydrogen fits this condition as its energy density is higher than typical fuels like gasoline or propane and much higher than any battery types. Also, fuel cells tested in the lab have obtained efficiencies greater than 90%; but, the weight of a conventional fuel cell is an issue with regard to the UAVs. The fuel cell presented in this study attempts to tackle the weight issue. To decrease weight, metallic bipolar plates were used in place of the typical carbon composite plates. Metallic bipolar plates have the added benefit of reducing material and machining cost. The open-cathode design allows oxygen to be supplied and the stack cooled from the same stream of air. This reduces the balance of plant for fuel cell operation and so, reduces cost and most importantly, weight. The fuel cell presented in this study will allow for longer flight times and quiet operation when compared to the conventional power sources.

The Viable But Nonculturable State of Kanagawa Positive and Negative Strains of Vibrio parahaemolyticus

Tonya C. Bates,James D. Oliver 한국미생물학회 2004 The journal of microbiology Vol.42 No.2

Ingestion of shellfish-associated Vibrio parahaemolyticus is the primary cause of potentially severe gastroenteritis in many countries. However, only Kanagawa phenomenon (hemolysin) positive (KP+) strains of V. parahaemolyticus are isolated from patients, whereas >99% of strains isolated from the environment do not produce this hemolysin (i.e. are KP-). The reasons for these differences are not known. Following a temperature downshift, Vibrio parahaemolyticus enters the viable but nonculturable (VBNC) state wherein cells maintain viability but cannot be cultured on routine microbiological media. We speculated that KP+ and KP- strains may respond differently to the temperature and salinity conditions of seawater by entering into this state which might account for the low numbers of culturable KP+ strains isolated from estuarine waters. The response of eleven KP+ and KP- strains of V. parahaemolyticus following exposure to a nutrient and temperature downshift in different salinities, similar to conditions encountered in their environment, was examined. The strains included those from which the KP+ genes had been selectively removed or added. Our results indicated that the ability to produce hemolysin did not affect entrance into the VBNC state. Further, VBNC cells of both biotypes could be restored to the culturable state following an overnight temperature upshift.

Properties Augmentation of Cast Hypereutectic Al–Si Alloy Through Friction Stir Processing

William P. Bates,Vivek Patel,Harikrishna Rana,Joel Andersson,Jeroen De Backer,Mattias Igestrand,Livan Fratini 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.1

The present endeavour is to augment mechanical attributes via friction stir processing (FSP) in hypereutectic aluminium–siliconcastings by the means of microstructural modifications and defects reduction. Wherein, the study proceeds with mainlytwo approaches namely, alteration in tool revolution (TR) and the number of FSP passes. The prepared specimens wereevaluated investigating volume fraction of porosities, microstructural characterizations and microhardness. Therefrom, thespecimen with highest number of passes delivered most uniform properties resulting from the reduction in casting porositiesand refined silicon particle uniform distribution throughout friction stir processed zone. This endeavour may be consideredas a footstep towards more industrial readied material transformation.

The state of democracy in Sub-Saharan Africa

Robert H. Bates,Ghada Fayad,Anke Hoeffler 한국외국어대학교 국제지역연구센터 2012 International Area Studies Review Vol.15 No.4

Africa experienced a wave of democratization over the past 20 years and this increase in democracy, we find, positively and significantly affects income per capita. Our dynamic panel data results suggest that countries only slowly converge to their long-run income values as predicted by current democracy levels, however. African countries may therefore be currently too democratic relative to their income levels. In keeping with this possibility, a significant number of countries are experiencing political ‘back sliding’: elections are won by the use of illicit tactics,term limits on political leaders have been overturned and there have been unconstitutional seizures of power.