Synthesis Of Butyl Acetate By Lipase-Catalysed Esterification

Ester is an aromatic compound naturally found in plants and fruits, which is animportant additive for food, beverages, pharmaceutical and cosmetic industries, giving flavour and fragrance. The compound is either supplied by natural resources or chemical synthesis. Lipase as biocatalyst shows great potential in aroma ester synthesis since lipase-catalysed reaction product is verified to be natural. In this study, butyl acetate was synthesised from acetic acid and n-butanol esterification catalysed by immobilized Candida rugosa lipase. Theprocess parameters which were optimized included reaction time, enzyme amount, temperature, and acetic acid/ethanol molar ratio were studied using one-factor-at-a-time (OFAT) method. Optimal molar conversion for butyl acetate of 81.33 % was obtained at 40 minutes incubation time with 50 U/ml of enzyme amount and substrate molar ratio of 1:1 (0.1 M) at 40 ℃ and 150 rpm. The kinetic parameters were also calculated using secondary data extracted from another researcher group. The data was fitted into Random Bi Bi, Ordered Bi Bi and Ping Pong Bi Bi mechanisms to compare the kinetic parameters obtained. The kinetic analysis of the esterification reactions was found to follow a Ping Pong Bi Bi mechanism with inhibition by one of the substrates, acetic acid. The fitted kinetic parameters obtained were Vmax = 249.05 mol/min.g, K m(A) = 46.25 mol/dm3 , K m(B) = 4.15 mol/dm3, KI = 15.09 mol/dm3

Impak Nasional : Program Pembelajaran Sepanjang Hayat (PSH) Tidak Formal di Malaysia

Merujuk kepada Pelan Strategik Pengajian Tinggi Negara (PSPTN), pembudayaan pembelajaran sepanjang hayat (PSH) merupakan Teras ke-6 bagi membolehkan individu memperolehi kemahiran baharu dan meningkatkan kemahiran sedia ada, serta dalam proses tersebut memperolehi manfaat sosioekonomi. Dalam aspek ini, peningkatan dalam kompetensi pekerja dijangka membolehkan Malaysia beralih daripada sektor pembuatan elektronik dan barangan perkilangan, ke sektor pembuatan barangan berasaskan pengetahuan intensif (knowledge-intensiJied goods). Kemajuan ke arah ekonomi berasaskan pengetahuan dalam era ICT, akan merealisasikan impian Malaysia untuk menjadi sebuah negara maju pada tahun 2020. Sehubungan dengan itu, kerajaan telah meningkatkan pelaburan dalam program PSH melalui pelbagai agensi kerajaan untuk membudayakan PSH dalam' kalangan rakyat Malaysia. Namun begitu, maklumat mengenai kerelevanan program PSH dalam latihan semula (reskilling) dan peningkatan kemahiran (upskilling) bagi peserta, hanya dapat diperolehi daripada maklum balas yang diberikan oleh peserta pada hari terakhir program PSH. Hasil maklum balas tersebut merupakan jangkaan peserta tentang kerelevanan kemahiran dan pengetahuan yang dipelajari. Buat masa ini, pola penyertaan dalam program PSH belum dikaji dan maklumat ini penting untuk mengenal pasti kesedaran awam dan ekuiti dalam peluang untuk menyertai program PSH (Strategi 2 PSPTN)

Replication and Meta-analysis of the Association between BDNF Val66Met Polymorphism and Cognitive Impairment in Patients Receiving Chemotherapy.

Cancer-related cognitive impairment (CRCI) adversely affects cancer patients. We had previously demonstrated that the BDNF Val66Met genetic polymorphism is associated with lower odds of subjective CRCI in the multitasking and verbal ability domains among breast cancer patients receiving chemotherapy. To further assess our previous findings, we evaluated the association of BDNF Val66Met polymorphism with subjective and objective CRCI in a temporally separate cohort of patients and pooled findings from both the original (n = 145) and current (n = 193) cohorts in a meta-analysis. Subjective CRCI was assessed using FACT-Cog. Objective CRCI was evaluated using computerized neuropsychological tests. Genotyping was carried out using Sanger sequencing. The association of BDNF Val66Met genotypes and CRCI was examined with logistic regression. A fixed-effect meta-analysis was conducted using the inverse variance method. In the meta-analysis (n = 338), significantly lower odds of CRCI were associated with Met allele carriers based on the global FACT-Cog score (OR = 0.52, 95% CI 0.29-0.94). Furthermore, Met allele carriers were at lower odds of developing impairment in the domains of memory (OR = 0.34, 95% CI: 0.17-0.70), multitasking (OR = 0.33, 95% CI: 0.18-0.59), and verbal ability (OR = 0.46, 95% CI: 0.24-0.88). Consistent with the previous study, lower odds of subjective CRCI among patients with the BDNF Met allele was observed after adjusting for potential confounders in the multitasking (OR = 0.30, 95% CI: 0.14-0.67) domain. In conclusion, carriers of the BDNF Met allele were protected against global subjective CRCI, particularly in the domains of memory, multitasking, and verbal ability. Our findings further contribute to the understanding of CRCI pathophysiology

The luminous type Ia supernova 2022ilv and its early excess emission

We present observations and analysis of the host-less and luminous type Ia supernova 2022ilv, illustrating it is part of the 2003fg-like family, often referred to as super-Chandrasekhar (Ia-SC) explosions. The ATLAS light curve shows evidence of a short-lived, pulse-like early excess, similar to that detected in another luminous type Ia supernova (SN 2020hvf). The light curve is broad and the early spectra are remarkably similar to SN 2009dc. Adopting a redshift of $z=0.026 \pm 0.005$ for SN 2022ilv based on spectral matching, our model light curve requires a large $^{56}$Ni mass in the range $0.7-1.5$ M$_{\odot}$, and a large ejecta mass in the range $1.6-2.3$ M$_{\odot}$. The early excess can be explained by fast-moving SN ejecta interacting with a thin, dense shell of circumstellar material close to the progenitor ($\sim 10^{13}$ cm), a few hours after the explosion. This may be realised in a double-degenerate scenario, wherein a white dwarf merger is preceded by ejection of a small amount ($\sim 10^{-3}-10^{-2}$ M$_{\odot}$) of hydrogen and helium-poor tidally stripped material. A deep pre-explosion Pan-STARRS1 stack indicates no host galaxy to a limiting magnitude of $r \sim 24.5$. This implies a surprisingly faint limit for any host of $M_r \gtrsim -11$, providing further evidence that these types of explosion occur predominantly in low-metallicity environments.Comment: Accepted to ApJL after minor revisio

Diagnostic Accuracy of the Electrocardiogram for Heart Failure With Reduced or Preserved Ejection Fraction

Current heart failure (HF) guidelines recommend electrocardiography (ECG) as an essential initial investigation in a patient's workup. 1 However, these recommendations were based on studies primarily including patients with HF with reduced ejection fraction (HFrEF). 1 , 2 , 3 Guidelines do not distinguish HFrEF from HF with preserved and mid-range ejection fraction (HFpEF and HFmrEF) in their ECG recommendations. We hypothesized that a normal ECG does not exclude HFpEF and has a considerably lower sensitivity for diagnosing HFpEF than HFrEF

A statistical method for region-based meta-analysis of genome-wide association studies in genetically diverse populations

Genome-wide association studies (GWAS) have become the preferred experimental design in exploring the genetic etiology of complex human traits and diseases. Standard SNP-based meta-analytic approaches have been utilized to integrate the results from multiple experiments. This fundamentally assumes that the patterns of linkage disequilibrium (LD) between the underlying causal variants and the directly genotyped SNPs are similar across the populations for the same SNPs to emerge with surrogate evidence of disease association. We introduce a novel strategy for assessing regional evidence of phenotypic association that explicitly incorporates the extent of LD in the region. This provides a natural framework for combining evidence from multi-ethnic studies of both dichotomous and quantitative traits that (i) accommodates different patterns of LD, (ii) integrates different genotyping platforms and (iii) allows for the presence of allelic heterogeneity between the populations. Our method can also be generalized to perform gene-based or pathway-based analyses. Applying this method on real GWAS data in type 2 diabetes (T2D) boosted the association evidence in regions well-established for T2D etiology in three diverse South-East Asian populations, as well as identified two novel gene regions and a biologically convincing pathway that are subsequently validated with data from the Wellcome Trust Case Control Consortium

A study assessing the association of glycated hemoglobin a1C (HbA1C) associated variants with HbA1C, chronic kidney disease and diabetic retinopathy in populations of asian ancestry

10.1371/journal.pone.0079767PLoS ONE811-POLN

Genome-Wide Association Study of Retinopathy in Individuals without Diabetes

10.1371/journal.pone.0054232PLoS ONE82

Genetic Associations of Type 2 Diabetes with Islet Amyloid Polypeptide Processing and Degrading Pathways in Asian Populations

10.1371/journal.pone.0062378PLoS ONE86