Beom-Sik Kim

Pyrolysis and catalytic upgrading of Citrus unshiu peel

Ex situ catalytic pyrolysis of Citrus unshiu (C. unshiu) peel was performed using a tandem μ-reactor-GC/MS consisting of two sequential furnaces. The pyrolyzates of C. unshiu peel, composed mainly of alcohols, ketones and furans produced in the 1st furnace of the reactor, were upgraded to aromatics by the use of catalysts in the 2nd furnace. Compared to wood powder, C. unshiu peel produced larger amounts of aromatics over HZSM-5(23). Among the various catalysts, HZSM-5(23) and HBETA(25) showed high aromatic yields, 6.78 C% and 9.69 C%, respectively. HBETA(25) produced large amounts of undesirable PAHs (3.59 C%). During the sequential catalytic upgrading test, the yield of BTEXs (benzene, toluene, ethylbenzene, xylenes) over HZSM-5(23) was reduced more slowly than that over HBETA(25) because of the slower deactivation of HZSM-5(23), which suggests that HZSM-5(23) is a more stable catalyst than the other catalysts used in this study during the sequential catalytic upgrading of C. unshiu peel pyrolyzates.

Clinical features of acute renal failure associated with hepatitis A virus infection.

Summary.  Acute hepatitis A (AHA) is one of the most common infectious diseases; it is usually a self‐limiting disease affecting the liver. Although extrahepatic manifestations are not common, some cases have been reported associated with acute renal failure. We reviewed the clinical features of patients with AHA complicated by acute renal failure (ARF group) and compared them with patients with noncomplicated AHA (non‐ARF group). The medical records of 208 consecutive patients with AHA who were diagnosed between January 2003 and October 2008 were reviewed. We identified 15 patients (7.2%) with ARF associated with AHA. There were no differences between the ARF and non‐ARF group with regard to gender and age. The peak value of alanine aminotransferase (ALT) (median: 6060 IU/L vs 1792 IU/L, P < 0.001), prothrombin time (PT) (International normalized ratio, median 1.72 vs 1.10, P < 0.001), and total bilirubin level (median: 9.6 mg/dL vs 6.3 mg/dL, P = 0.04) were significantly higher in the ARF than in the non‐ARF group. Twelve patients (80%) recovered completely with haemodialysis (seven patients, 46.7%) or only conservative management (five patients, 33.3%), while one patient underwent liver transplantation because of fulminant hepatic failure, and two patients died because of fulminant hepatic failure. There were no deaths among patients with noncomplicated AHA in the non‐ARF group. Five patients underwent kidney biopsy; two patients were diagnosed with acute tubular necrosis, two patients with acute interstitial nephritis with IgA nephropathy and one patient with acute tubulointerstitial nephritis. All patients in the ARF group had microscopic haematuria and proteinuria (100%vs 31.1%, P < 0.001). Urine sodium levels were more than 10 mEq/L in 10 patients. The findings of high urinary sodium concentrations, microscopic haematuria and proteinuria did not support the diagnosis of hepatorenal syndrome (HRS). Patients with AHA with ARF had higher ALT levels, more prolonged PTs, and higher total bilirubin levels. The prognosis for these patients was poorer than for those without ARF. However, the patients with ARF and nonfulminant AHA had recovered with proper treatment and should not be confused with patients that have HRS.

The Role of Ruthenium on Carbon-Supported PtRu Catalysts for Electrocatalytic Glycerol Oxidation under Acidic Conditions

A series of binary PtRu catalysts with different Pt/Ru atomic ratios (from 7:3 to 3:7) were synthesized on a carbon support using the colloidal method; they were then used for electrooxidation of glycerol in acid media. X‐ray diffraction, transmission electron microscopy, X‐ray photoelectron spectroscopy, and X‐ray absorption spectroscopy analyses were used to investigate particle size, size distribution, and structural and electronic properties of the prepared catalysts. Ru added to the Pt‐based catalysts caused structural and electronic modifications over the PtRu alloy catalyst formation. The electrocatalytic activities of PtRu/C series catalysts were investigated using cyclic voltammetry. The Pt5Ru5/C catalyst shows enhanced catalytic activity at least 40 % higher than that of the Pt/C catalyst, with improved stability for glycerol electrooxidation; these improvements are attributed to structural and electronic modifications of the Pt catalysts. Using an electrocatalytic batch reactor, product analysis after the oxidation reaction was performed by high‐performance liquid chromatography to determine and compare the reaction pathways on the Pt/C and PtRu/C catalysts. To understand different catalytic activities of glycerol oxidation on the PtRu alloy surfaces, density functional calculations were performed.

Catalytic rapid pyrolysis of Quercus variabilis over nanoporous catalysts

Catalytic rapid pyrolysis of Quercus variabilis, a Korean native tree species, was carried out using Py-GC/MS. Mesoporous MFI, which has both nanopores and micropores, and three nanoporous materials, Al-MCM-41, Al-SBA-15, and γ-Al2O3, were used as the catalyst. The acid sites of mesoporous MFI were strong Bronsted acid sites, whereas those of nanoporous materials were mostly weak acid sites. The composition of the product bio-oil varied greatly depending on the acid characteristics of the catalyst used. Phenolics were the most abundant species in the bio-oil, followed by acids and furanics, obtained over Al-MCM-41 or Al-SBA-15 with weak acid sites, whereas aromatics were the most abundant species produced over mesoporous MFI with strong acid sites, followed by phenolics. Aromatics, phenolics, and furanics are all important chemicals contributing to the improvement of bio-oil quality.

Catalytic Pyrolysis of Municipal Plastic Film Wastes Over Nanoporous Al-MCM-41

A mesoporous material, Al-MCM-41, was applied to the catalytic pyrolysis of municipal plastic film waste (MPFW) to produce large amounts of valuable hydrocarbons. Compared to non-catalytic pyrolysis, the catalytic pyrolysis of MPFW over Al-MCM-41 revealed a lower decomposition temperature and activation energy upon thermogravimetric analysis. Heavy aliphatic hydrocarbons, which are the major products of non-catalytic pyrolysis, were cracked into small hydrocarbons and converted efficiently to aromatic hydrocarbons by catalytic pyrolysis over Al-MCM-41. The activity of catalytic conversion was enhanced by increasing the catalyst to reactant ratio.

The effect of pretransplantation lamivudine resistance on the prognosis of liver transplant recipients.

BACKGROUND Since the introduction of lamivudine to treat chronic hepatitis B (CHB), the prevalence of lamivudine resistance is increasing among orthotopic liver transplant (OLT) candidates in Korea. OBJECTIVE The purpose of this study was to evaluate the effect of pre-OLT lamivudine-resistance on the post-OLT prognosis of recipients. MATERIAL AND METHODS Consecutive OLT recipient at a single tertiary care center (n = 8) between September 1999 and August 2009 were tested preoperatively for genotypic lamivudine resistance. We compared overall survival as well as incidences of graft failure, recurrent hepatitis, and hepatocellular carcinoma (HCC) between patients with (n = 35) versus without (n = 46) lamivudine-resistance. RESULTS Mortality occurred in 2 resistant and 3 nonresistant individuals. The occurrences of graft failure, recurrent hepatitis, and HCC were 1, 2, and 2 cases, respectively, in the resistance group versus 2, 2, and 2 cases, respectively, in the nonresistance cohort. Univariate analysis showed no significant difference in survival, graft failure, HCC occurrence, and recurrent hepatitis. CONCLUSIONS Our results indicated that pre-OLT lamivudine-resistance did not significantly affect the post-OLT prognosis. Thus, lamivudine-resistance may not be a barrier when considering OLT in patients with underlying CHB as a therapeutic modality, if it is treated with appropriate antiviral agents.