Measurement of Antioxidant Effects on the Auto-oxidation Kinetics of Methyl Oleate – Methyl Laurate Blend as a Surrogate Biodiesel System

This research investigates the feasibility of methyl oleate-methyl laurate blend as a surrogate biodiesel system which represents jatropha-coconut oil biodiesel, a potentially suitable formulation for tropical climate, to quantify the efficacy of antioxidant additives in terms of their kinetic parameters. This blend was tested by the Rancimat EN14112 standard method. The Rancimat tests results were used to determine the primary oxidation induction period (OIP) and first-order rate constants and activation energies. Addition of BHT and EcotiveTM antioxidants reduces the rate constants (k, h-1) between 15 to 90% in the 50-200 ppm dose range, with EcotiveTM producing significantly lower k values. Higher dose reduces the rate constant, while oleate/laurate ratio produces no significant impact. Antioxidants increase the oxidation activation energy (Ea, kJ/mol) by 180 to almost 400% relative to the non-antioxidant value of 27.0 kJ/mol. EcotiveTM exhibits lower Ea, implying that its higher efficacy stems from a better steric hindrance as apparent from its higher pre-exponential factors. The ability to quantify oxidation kinetic parameters is indicative of the usefulness of methyl oleate-laurate pure FAME blend as a biodiesel surrogate offering better measurement accuracy due to the absence of pre-existing antioxidants in the test samples.

Measurement of Antioxidant Effects on the Auto-oxidation Kinetics of Methyl Oleate – Methyl Laurate Blend as a Surrogate Biodiesel System

This research investigates the feasibility of methyl oleate-methyl laurate blend as a surrogate biodiesel system which represents jatropha-coconut oil biodiesel, a potentially suitable formulation for tropical climate, to quantify the efficacy of antioxidant additives in terms of their kinetic parameters. This blend was tested by the Rancimat EN14112 standard method. The Rancimat tests results were used to determine the primary oxidation induction period (OIP) and first-order rate constants and activation energies. Addition of BHT and EcotiveTM antioxidants reduces the rate constants (k, h-1) between 15 to 90% in the 50-200 ppm dose range, with EcotiveTM producing significantly lower k values. Higher dose reduces the rate constant, while oleate/laurate ratio produces no significant impact. Antioxidants increase the oxidation activation energy (Ea, kJ/mol) by 180 to almost 400% relative to the non-antioxidant value of 27.0 kJ/mol. EcotiveTM exhibits lower Ea, implying that its higher efficacy stems from a better steric hindrance as apparent from its higher pre-exponential factors. The ability to quantify oxidation kinetic parameters is indicative of the usefulness of methyl oleate-laurate pure FAME blend as a biodiesel surrogate offering better measurement accuracy due to the absence of pre-existing antioxidants in the test samples. Copyright © 2017 BCREC GROUP. All rights reserved Received: 6th July 2016; Revised: 7th December 2016; Accepted: 30th January 2017 How to Cite: Samadhi, T.W., Hirotsu, T., Goto, S. (2017). Measurement of Antioxidant Effects on the Auto-oxidation Kinetics of Methyl Oleate-Methyl Laurate Blend as a Surrogate Biodiesel System. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2): 157-166 (doi:10.9767/bcrec.12.2.861.157-166) Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.861.157-16

Characteristics of Oxidative Storage Stability of Canola Fatty Acid Methyl Ester Stabilised with Antioxidants

The storage effects on the oxidation characteristics of fatty acid methyl ester of canola oil (CME) were investigated in this study.CME stabilised with two antioxidants, i.e.2,6-di-tert-bytyl-p-cresol (BHT) and 6,6-di-tert-butyl-2, 2'-methylendi-p-cresol (BPH), was stored at 20, 40 and 60°C.The oxidation stability data were measured by the Rancimat test method and it was found that both BHT and BPH addition increased the oxidation resistance of the CME. The results showed that when BPH or BHT was added at a concentration of 100 ppm, the oxidation induction period of the neat CME samples increased from 5.53 h to 6.93 hand 6.14 h, respectively. Comparing both antioxidants, BPH proved to be more effective in increasing the oxidation resistance when both antioxidants were added at the same concentration. Furthermore, the oxidation induction timedecreased linearly with the storage time. It was shown that the oxidation occurred rapidly in the first 8 weeks of storage. Later, a kinetic study was undertaken and first-order kinetics were applied to explain the oxidation characteristics of the CME added with antioxidants. This kinetic study focused on exploiting the activation energy values obtained from the Arrheniusequations. Also, the oxidation effects on other quality parameters, including acid value, peroxide value, kinematic viscosity, and water content, were examined

Plate : persistent memory management for nonvolatile main memory

Over the past few years, nonvolatile memory has actively been researched and developed. Therefore, studying operating system (OS) designs predicated on the main memory in the form of a nonvolatile memory and studying methods to manage persistent data in a virtual memory are crucial to encourage the widespread use of nonvolatile memory in the future. However, the main memory in most computers today is volatile, and replacing highcapacity main memory with nonvolatile memory is extremely cost-prohibitive. This paper proposes an OS structure for nonvolatile main memory. The proposed OS structure consists of three functions to study and develop OSs for nonvolatile main memory computers. First, a structure, which is called plate, is proposed whereby persistent data are managed assuming that nonvolatile main memory is present in a computer. Second, we propose a persistent-data mechanism to make a volatile memory function as nonvolatile main memory, which serves as a basis for the development of OSs for computers with nonvolatile main memory. Third, we propose a continuous operation control using the persistent-data mechanism and plates. This paper describes the design and implementation of the OS structure based on the three functions on The ENduring operating system for Distributed EnviRonment and describes the evaluation results of the proposed functions

Serum Reactivity Against Bacterial Pyruvate Dehydrogenase: Increasing the Specificity of Anti-Mitochondrial Antibodies for the Diagnosis of Primary Biliary Cirrhosis

Antimitochondrial antibodies (AMA) are the serum hallmark of primary biliary cirrhosis (PBC). However, AMA-positivity can be found in non-PBC sera when lower dilutions are used, thus raising issues about the specificity and sensitivity of the test. AMA reacts primarily with the lipoylated domains of pyruvate dehydrogenase-E2 (PDC-E2) which is highly conserved across species, including bacteria. We studied 77 serum samples, including 24 from patients with anti-PDC-E2-positive PBC and 53 controls (16 with autoimmune hepatitis (AIH), 10 with primary sclerosing cholangitis (PSC), and 27 healthy individuals) for their reactivities at serial dilutions (1:10, 1:20 and 1:40) against Escherichia coli DH5 alpha lysate overexpressing human PDC-E2 using immunoblotting (IB). A murine anti-human PDC-E2 monoclonal antibody (mAB) was used as control. We further studied positive sera using adsorption with a synthetic E. coli peptide sharing similarity with human PDC-E2. Finally, we verified whether a unique buffer for E. coli preparation could reduce non-specific serum reactivity. Results demonstrated that 100% of anti-PDC-E2-positive PBC and up to 38% of control sera at 1:10 dilution recognized E. coli PDC-E2 at IB while dilution tests indicated that the overall potency of PBC reactivity was 100-fold higher compared to controls. In fact, a subgroup (20-38%) of non-PBC sera were positive at low titers but lost the reactivity when absorbed with the synthetic E. coli peptide. Finally, our unique buffer reduced the reactivity of non-PBC sera as measured by ELISA. In conclusion, we demonstrated that weak cross-reactivity with E. coli PDC-E2 occurs in non-PBC sera at lower dilutions and that such reactivity is not due to AMA-positivity. The use of a specific buffer might avoid the risk of false positive AMA determinations when E. coli-expressed recombinant antigens are used

Absence of germline mono-allelic promoter hypermethylation of the CDH1 gene in gastric cancer patients

<p>Abstract</p> <p>Background</p> <p>Germline mono-allelic promoter hypermethylation of the <it>MLH1 </it>or <it>MSH2 </it>gene in families with hereditary nonpolyposis colorectal cancer has recently been reported. The purpose of this study was to evaluate if germline promoter hypermethylation of the tumor suppressor gene <it>CDH1 </it>(<it>E-cadherin</it>) might cause predisposition to gastric cancer.</p> <p>Methods</p> <p>We prepared two groups of samples, a group of blood samples from 22 patients with familial gastric cancer or early-onset gastric cancer selected from among 39 patients, and a group of non-cancerous gastric tissue samples from 18 patients with sporadic gastric cancer showing loss of CDH1 expression selected from among 159 patients. We then investigated the allele-specific methylation status of the <it>CDH1 </it>promoter by bisulfite sequencing of multiple clones.</p> <p>Results</p> <p>Although there was a difference between the methylation level of the two alleles in some samples, there was no mono-allelic promoter hypermethylation in any of the samples.</p> <p>Conclusion</p> <p>These results suggest that germline mono-allelic hypermethylation of the <it>CDH1 </it>promoter is not a major predisposing factor for gastric cancer.</p

Coordinated elevation of membrane type 1-matrix metalloproteinase and matrix metalloproteinase-2 expression in rat uterus during postpartum involution

BACKGROUND: The changes occurring in the rodent uterus after parturition can be used as a model of extensive tissue remodeling. As the uterus returns to its prepregnancy state, the involuting uterus undergoes a rapid reduction in size primarily due to the degradation of the extracellular matrix, particularly collagen. Membrane type-I matrix metalloproteinase (MT1-MMP) is one of the major proteinases that degrades collagen and is the most abundant MMP form in the uterus. Matrix metalloproteinase-2(MMP-2) can degrade type I collagen, although its main function is to degrade type IV collagen found in the basement membrane. To understand the expression patterns of matrix metalloproteinases (MMPs) in the rat uterus, we analyzed their activities in postpartum uterine involution. METHODS: We performed gelatin zymography, northern blot analysis and immunohistochemistry to compare the expression levels of MT1-MMP, MMP-2, matrix metalloproteinase-9 (MMP-9) and the tissue inhibitors of MMPs-1 and 2 (TIMP-1 and TIMP-2) in the rat uterus 18 h, 36 h and 5 days after parturition with their expression levels during pregnancy (day 20). RESULTS: We found that both MT1-MMP and MMP-2 localized mainly in the cytoplasm of uterine interstitial cells. The expression levels of MT1-MMP and MMP-2 mRNAs and the catalytic activities of the expressed proteins significantly increased 18 h and 36 h after parturition, but at postpartum day 5, their mRNA expression levels and catalytic activities decreased markedly. The expression levels of MMP-9 increased 18 h and 36 h after parturition as determined by gelatin zymography including the expression levels of TIMP-1 and TIMP-2. CONCLUSION: These expression patterns indicate that MT1-MMP, MMP-2, MMP-9, TIMP-1 and TIMP-2 may play key roles in uterine postpartum involution and subsequent functional regenerative processes