Acute hepatitis A, B and C but not D is still prevalent in Mongolia: a time trend analysis
CLINICAL AND MOLECULAR HEPATOLOGY
Authors: Baatarkhuu, Oidov; Lee, Hye Won; George, Jacob; Munkh-Orshikh, Dashchirev; Enkhtuvshin, Baasankhuu; Ariunaa, Sosorbaram; Eslam, Mohammed; Ahn, Sang Hoon; Han, Kwang-Hyub; Kim, Do Young
Abstract
Background/Aims: Mongolia has one of the highest hepatitis A, C, B and D infection incidences worldwide. We sought to investigate changes in the proportion of acute viral hepatitis types in Mongolia over the last decade. Methods: The cohort comprised 546 consecutive patients clinically diagnosed with acute viral hepatitis from January 2012 to December 2014 in Ulaanbaatar Hospital, Mongolia. A time trend analysis investigating the change in proportion of acute hepatitis A virus, hepatitis C virus (HCV), hepatitis B virus (HBV) and hepatitis delta virus (HDV) infection among the cohort with respect to a previous published study was undertaken. Results: Acute hepatitis A, B and C was diagnosed in 50.9%, 26.2% and 6.0% of the cohort. Notably, 16.8% of the cohort had a dual infection. The etiologies of acute viral hepatitis were varied by age groups. The most common cause of acute viral hepatitis among 2-19 year olds was hepatitis A, HBV and superinfection with HDV among 20-40 year olds, and HCV among 40-49 year olds. Patients with more than one hepatitis virus infection were significantly older, more likely to be male and had a higher prevalence of all risk factors for disease acquisition. These patients also had more severe liver disease at presentation compared to those with mono-infection. Conclusions: Acute viral hepatitis is still prevalent in Mongolia. Thus, the need for proper infection control is increasing in this country.
Onboard Natural Gas Reforming for Heavy Duty Vehicles
SAE INTERNATIONAL JOURNAL OF COMMERCIAL VEHICLES
Authors: Weiss, Brian; Beutel, Tilman W.; Chapman, Bryan R.; Saathoff, Jonathan D.; Merchant, Shame; Majano, Gerardo J.; Weissman, Walter
Abstract
Powertrain simulations and catalyst studies showed the efficiency credits and feasibility of onboard reforming as a way to recover waste heat from heavy duty vehicles (HDVs) fueled by natural gas (NG). Onboard reforming involves 1) injecting NG into the exhaust gas recycle (EGR) loop of the HDV, 2) reforming NG on a catalyst in the EGR loop to hydrogen and carbon monoxide, and 3) combusting the reformed fuel in the engine. The reformed fuel has increased heating value (4-10% higher LHV) and flame speed over NG, allowing stable flames in spark ignition (SI) engines at EGR levels up to 25-30%. A sulfur-tolerant reforming catalyst was shown to reform a significant amount of NG (15-30% conversion) using amounts of precious metal near the current practice for HDV emissions control (10 g rhodium). Engine simulations showed that the high EGR levels enabled by onboard reforming are used most effectively to control engine load instead of waste-gating or throttling. This leads to 3% efficiency gain due to reduced pumping losses and enables the engine to run while the catalyst is inactive, such as during a cold start or regeneration. Several powertrain layouts were assessed to show that a net efficiency gain of 10% is achievable when reforming occurs in a reactor that allows heat exchange with the non-recycled exhaust. The size of the heat exchange reactor was shown to be (4 ft. length, 7-10 in. diameter). The next steps to achieve onboard reforming include the development of the heat exchange reactor and validation with real engine testing.