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An acidic ionic liquid-conventional alkali-catalyzed biodiesel production process
Yasir Ali Elsheikh,Zakaria Man,Faheem Hassan Akhtar 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.3
A study was undertaken to prepare biodiesel via two-step process using ionic liquid as first step catalystdue to the unsuitability of using the straight alkaline-catalyzed transesterification of high FFA presented in crude palmoil (CPO). In the first step, esterification of the FFA presented in the CPO was carried out using butylimidazolium hydrogensulfate (BIMHSO4), in which the acid value was reduced from 6.93 to 1.02mg KOH/g and then, KOH-catalyzedtransesterification was applied. The conversion rate of FFA attained 85.3% when 4.8 wt% of BIMHSO4 was appliedto the reaction system containing methanol to CPO ratio of 12 : 1 reacted at 170 oC for 150min. The final yield in 97.3%revealed that the process proposed in this study could lead to an excellent biodiesel meeting the ASTM requirements. Furthermore, this new two-step catalysis process could solve the old conventional catalysis process drawbacks.
Ali, Kashif,Mahjabeen, Ishrat,Sabir, Maimoona,Baig, Ruqia Mehmood,Zafeer, Maryam,Faheem, Muhammad,Kayani, Mahmood Akhtar Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.18
Apurinic/apyrimidinic endonuclease 1 (APEX1) is a multifunctional protein which plays a central role in the BER pathway. APEX1 gene being highly polymorphic in cancer patients and has been indicated to have a contributive role in Apurinic/apyrimidinic (AP) site accumulation in DNA and consequently an increased risk of cancer development. In this case-control study, all exons of the APEX1 gene and its exon/intron boundaries were amplified in 530 breast cancer patients and 395 matched healthy controls and then analyzed by single-stranded conformational polymorphism followed by sequencing. Sequence analysis revealed fourteen heterozygous mutations, seven 5'UTR, one 3'UTR, two intronic and four missense. Among identified mutations one 5'UTR (rs41561214), one 3'UTR (rs17112002) and one missense mutation (Ser129Arg, Mahjabeen et al., 2013) had already been reported while the remaining eleven mutations. Six novel mutations (g.20923366T>G, g.20923435G>A, g.20923462G>A, g.20923516G>A, 20923539G>A, g.20923529C>T) were observed in 5'UTR region, two (g.20923585T>G, g.20923589T>G) in intron1 and three missense (Glu101Lys, Ala121Pro, Ser123Trp) in exon 4. Frequencues of 5'UTR mutations; g.20923366T>G, g.20923435G>A and 3'UTR (rs17112002) were calculated as 0.13, 0.1 and 0.1 respectively. Whereas, the frequency of missense mutations Glu101Lys, Ser123Trp and Ser129Arg was calculated as 0.05. A significant association was observed between APEX1 mutations and increased breast cancer by ~9 fold (OR=8.68, 95%CI=2.64 to 28.5) with g.20923435G>A (5'UTR), ~13 fold (OR= 12.6, 95%CI=3.01 to 53.0) with g.20923539G>A (5'UTR) and~5 fold increase with three missense mutations [Glu101Lys (OR=4.82, 95%CI=1.97 to 11.80), Ser123Trp (OR=4.62, 95%CI=1.7 to 12.19), Ser129Arg (OR=4.86, 95%CI=1.43 to 16.53)]. The incidence of observed mutations was found higher in patients with family history and with early menopause. In conclusion, our study demonstrates a significant association between germ line APEX1 mutations and breast cancer patients in the Pakistani population.