Transesterification of palm oil by an immobilized rhizomucor miehei lipase / A.Z. Hazlina and H.M. Ghazali

Enzymatic transesterification of RED palm oil was studied. Transesterification was done by reacting RBD palm oil with an immobilized R. miehei lipase in water-saturated hexane at various reaction temperatures. Analyses were done on the transesterified oils triglyceride composition and its melting characteristics using HPLC and DSC, respectively. Transesterification increased the concentration of MMM, OOL, MMP, 000 and PPS at reaction temperatures of 50°C and 60°C. At 30°C and 40°C, MMM, OOL, MMP was observed to increase. The degree of transesterification was between 18% and 46%, which coincided with the degree of hydrolysis between 1.9% and 2.5%. Percentage of triglycerides retained after transesterification was between 83% and 85%. Lowest transesterification rate was noted when palm oil was transesterified at 30°e. Generally, the heating thermogram of palm oil transesterified at different reaction temperatures showed three different regions compared to the non- transesterified palm oil. One new peak was found to be sandwiched between the low-T and high-T peaks. However, this peak was not observed in palm oil transesterified at 60°e. One peak at the high-T region was also observed for heating thermogram of oil transesterified at 60°C, compared to two peaks formed for the other reaction temperatures studied. The transesterified oils started to melt at between -25.74°C and -24.53°C and totally melted at between 43°C and 45.5°C. The non- transesterified oil started to melt at -24.65°C and totally melted at 43.2°C

Plant vegetative stages and drying methods affect flavonoid content of Clinacanthus nutans extracts

Background: Clinacanthus nutans, also known as ‘Sabah snake grass’ or ‘Belalai gajah’, is a herb well known locally for its medicinal values. The primary chemical constituents of the leaves are schaftoside, vitexin, isovitexin, orientin and isoorientin, and antiviral activity is shown by two glycoglycerolipids. Despite the importance of C. nutans, complete information with respect to commercial production and postharvest handling of the herb in the local herbal industry is still lacking. Thus, the objective of this study was to determine the optimum postharvest handling processes that could retain the quality of phytochemicals of C. nutans.Materials and Methods: The flavonoid compounds of C. nutans were analysed by using ultra fast liquid chromatography (UFLC). Total phenolic content and antioxidant activity were determined using a spectrophotometer.Results: The total phenolic compounds and antioxidant activity in C. nutans were found to be higher in the young vegetative stage than in the mature vegetative stage. Flavonoid compounds (schaftoside, isovitexin, vitexin and orientin) were also found to be highest in the young vegetative plant compared to the mature vegetative plant. All of the assayed phytochemicals and flavonoid compounds levels were found to be highest in oven dried samples compared to the sun, air and solar dried samples.Conslusion: This study suggests that oven-drying young vegetative C. nutans plant material is the optimum method to retain postharvest quality.Keywords: Flavonoid, Sabah snake grass, schaftoside, vitexin, dryin

Plant Vegetative Stages and Drying Methods Affect Flavonoid Content of Clinacanthus nutans Extracts

Background: Clinacanthus nutans, also known as ‘Sabah snake grass’ or ‘Belalai gajah’, is a herb well known locally for its medicinal values. The primary chemical constituents of the leaves are schaftoside, vitexin, isovitexin, orientin and isoorientin, and antiviral activity is shown by two glycoglycerolipids. Despite the importance of C. nutans, complete information with respect to commercial production and postharvest handling of the herb in the local herbal industry is still lacking. Thus, the objective of this study was to determine the optimum postharvest handling processes that could retain the quality of phytochemicals of C. nutans. Materials and Methods: The flavonoid compounds of C. nutans were analysed by using ultra fast liquid chromatography (UFLC). Total phenolic content and antioxidant activity were determined using a spectrophotometer. Results: The total phenolic compounds and antioxidant activity in C. nutans were found to be higher in the young vegetative stage than in the mature vegetative stage. Flavonoid compounds (schaftoside, isovitexin, vitexin and orientin) were also found to be highest in the young vegetative plant compared to the mature vegetative plant. All of the assayed phytochemicals and flavonoid compounds levels were found to be highest in oven dried samples compared to the sun, air and solar dried samples. Conslusion: This study suggests that oven-drying young vegetative C. nutans plant material is the optimum method to retain postharvest quality

Measurement of the total cross section and ρ -parameter from elastic scattering in pp collisions at √s=13 TeV with the ATLAS detector

In a special run of the LHC with β⋆=2.5 km, proton–proton elastic-scattering events were recorded at s√=13 TeV with an integrated luminosity of 340 μb−1 using the ALFA subdetector of ATLAS in 2016. The elastic cross section was measured differentially in the Mandelstam t variable in the range from −t=2.5⋅10−4 GeV2 to −t=0.46 GeV2 using 6.9 million elastic-scattering candidates. This paper presents measurements of the total cross section σtot, parameters of the nuclear slope, and the ρ-parameter defined as the ratio of the real part to the imaginary part of the elastic-scattering amplitude in the limit t→0. These parameters are determined from a fit to the differential elastic cross section using the optical theorem and different parameterizations of the t-dependence. The results for σtot and ρ are σtot(pp→X)=104.7±1.1 mb ,ρ=0.098±0.011. The uncertainty in σtot is dominated by the luminosity measurement, and in ρ by imperfect knowledge of the detector alignment and by modelling of the nuclear amplitude.publishedVersio

Search for pair production of boosted Higgs bosons via vector-boson fusion in the bb¯bb¯ final state using pp collisions at √s = 13 TeV with the ATLAS detector

A search for Higgs boson pair production via vector-boson fusion is performed in the Lorentz-boosted regime, where a Higgs boson candidate is reconstructed as a single large-radius jet, using 140 fb−1 of proton–proton collision data at √s = 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. Only Higgs boson decays into bottom quark pairs are considered. The search is particularly sensitive to the quartic coupling between two vector bosons and two Higgs bosons relative to its Standard Model prediction, K2V . This study constrains K2V to 0.55 < K2V < 1.49 at the 95% confidence level. The value K2V = 0 is excluded with a significance of 3.8 standard deviations with other Higgs boson couplings fixed to their Standard Model values. A search for new heavy spin-0 resonances that would mediate Higgs boson pair production via vector-boson fusion is carried out in the mass range of 1–5 TeV for the first time under several model and decay-width assumptions. No significant deviation from the Standard Model hypothesis is observed and exclusion limits at the 95% confidence level are derived

Charged-hadron production in pp, p+Pb, Pb+Pb, and Xe+Xe collisions at sNN−−−√ = 5 TeV with the ATLAS detector at the LHC

This paper presents measurements of charged-hadron spectra obtained in pp, p+Pb, and Pb+Pb collisions at s√ or sNN−−−√ = 5.02 TeV, and in Xe+Xe collisions at sNN−−−√ = 5.44 TeV. The data recorded by the ATLAS detector at the LHC have total integrated luminosities of 25 pb−1, 28 nb−1, 0.50 nb−1, and 3 μb−1, respectively. The nuclear modification factors RpPb and RAA are obtained by comparing the spectra in heavy-ion and pp collisions in a wide range of charged-particle transverse momenta and pseudorapidity. The nuclear modification factor RpPb shows a moderate enhancement above unity with a maximum at pT ≈ 3 GeV; the enhancement is stronger in the Pb-going direction. The nuclear modification factors in both Pb+Pb and Xe+Xe collisions feature a significant, centrality-dependent suppression. They show a similar distinct pT-dependence with a local maximum at pT ≈ 2 GeV and a local minimum at pT ≈ 7 GeV. This dependence is more distinguishable in more central collisions. No significant |η|-dependence is found. A comprehensive comparison with several theoretical predictions is also provided. They typically describe RAA better in central collisions and in the pT range from about 10 to 100 GeV

Search for single production of vector-like T quarks decaying into Ht or Zt in pp collisions at s√ = 13 TeV with the ATLAS detector

This paper describes a search for the single production of an up-type vector-like quark (T) decaying as T → Ht or T → Zt. The search utilises a dataset of pp collisions at s√ = 13 TeV collected with the ATLAS detector during the 2015–2018 data-taking period of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. Data are analysed in final states containing a single lepton with multiple jets and b-jets. The presence of boosted heavy resonances in the event is exploited to discriminate the signal from the Standard Model background. No significant excess above the Standard Model expectation is observed, and 95% CL upper limits are set on the production cross section of T quarks in different decay channels. The results are interpreted in several benchmark scenarios to set limits on the mass and universal coupling strength (κ) of the vector-like quark. For singlet T quarks, κ values above 0.53 are excluded for all masses below 2.3 TeV. At a mass of 1.6 TeV, κ values as low as 0.35 are excluded. For T quarks in the doublet scenario, where the production cross section is much lower, κ values above 0.72 are excluded for all masses below 1.7 TeV, and this exclusion is extended to κ above 0.55 for low masses around 1.0 TeV