Hydrotreating Reactivities of Atmospheric Residues and Correlation with Their Composition and Properties
ENERGY & FUELS
Authors: Cui, Qingyan; Ma, Xiaoliang; Nakano, Koji; Nakabayashi, Koji; Miyawaki, Jin; Al-Mutairi, Adel; Marafi, Abdulazim M. J.; Park, Joo-Il; Yoon, Seong-Ho; Mochida, Isao
In order to better understand the effects of composition and properties of atmospheric residues (AR) on their reactivities for hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodevanadium (HDV), hydrodenickel (HDNi), hydrodeasphaltene (HDAsp), and hydrodeconradson-carbon-residue (HDCCR) in the hydrotreating process, analysis and characterization of three ARs (AA-AR, AB-AR, and AM-AR) from Arabia crudes were conducted, and their hydrotreating reactivities were evaluated in a pilot unit over a catalyst system at 370 degrees C under a H-2 pressure of 13.5 MPa by comparing the conversions of the various species and their rate constants on each catalyst. The overall reactivity of various species decreases in the order of vanadium species > sulfur species approximate to asphaltenes > nickel species > Conradson carbon residue precursor > nitrogen species, regardless of the sources of the ARs. Reactivities of the three ARs in HDS, HDV, and HDAsp increase in the order of AB-AR < AA-AR < AM-AR, while reactivities of the three ARs in HDNi, HDCCR, and HDN are similar. The higher nitrogen and asphaltenes concentrations and larger density of AR have strong and negative effects on the HDS, HDV, and HDAsp reactivities but no significant effect on the HDN, HDNi, and HDCCR reactivities. The B parameter obtained from electron spin resonance analysis can be a good index to predict the HDV reactivity of A.R.
Innate immune recognition and modulation in hepatitis D virus infection
WORLD JOURNAL OF GASTROENTEROLOGY
Authors: Jung, Stephanie; Altstetter, Sebastian Maximilian; Protzer, Ulrike
Hepatitis D virus (HDV) is a global health threat with more than 15 million humans affected. Current treatment options are largely unsatisfactory leaving chronically infected humans at high risk to develop liver cirrhosis and hepatocellular carcinoma. HDV is the only human satellite virus known. It encodes only two proteins, and requires Hepatitis B virus (HBV) envelope protein expression for productive virion release and spread of the infection. How HDV could evolve and why HBV was selected as a helper virus remains unknown. Since the discovery of Na+-taurocholate co-transporting polypeptide as the essential uptake receptor for HBV and HDV, we are beginning to understand the interactions of HDV and the immune system. While HBV is mostly regarded a stealth virus, that escapes innate immune recognition, HBV-HDV coinfection is characterized by a strong innate immune response. Cytoplasmic RNA sensor melanoma differentiation antigen 5 has been reported to recognize HDV RNA replication and activate innate immunity. Innate immunity, however, seems not to impair HDV replication while it inhibits HBV. In this review, we describe what is known up-to-date about the interplay between HBV as a helper and HDV's immune evasion strategy and identify where additional research is required.