Optimization of Enzymatically Prepared Hexyl Butyrate by Lipozyme IM-77

Hexyl butyrate, a green note flavour compound, is widely used in the food industry. The ability of immobilised lipase (Lipozyme IM-77) from Rhizomucor miehei to catalyse the transesterification of hexanol and tributyrin was investigated in this study. Response surface methodology (RSM) and five-level-five-factor central composite rotatable design (CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time (2 to 10 h), temperature (25 to 65 °C), enzyme amount (10 to 50 %), substrate amount (in mol) ratio of tributyrin to hexanol (1:1 to 3:1), and added water content (0 to 20 %), on percentage amount (in mol) conversion of hexyl butyrate by transesterification. Reaction time and enzyme amount were the most important variables and substrate amount (in mol) ratio had less effect on the percentage of amount (in mol) conversion. Based on canonical analysis, the optimum synthesis conditions were: reaction time 8.3 h, temperature 50 °C, enzyme amount 42.7 %, substrate amount (in mol) ratio 1.8:1, and added water 12.6 %. The predicted value was 96.2 % and actual experimental value 95.3 % of the amount (in mol) conversion

Ediacaran Macro Body Fossils

This paper, Ediacaran Macro Body Fossils, reports a new discovery of well preserved three dimensional macro body fossils of the Ediacaran Period in central YunNan province in the People's Republic of China. These body fossils will enable more detailed and in-depth exploration of the evolution of multi-cellular macro organisms on this planet, whereas in the past, researches could only rely on cast or imprint fossils

Microfluidic assisted synthesis of silver nanoparticle–chitosan composite microparticles for antibacterial applications

AbstractSilver nanoparticle (Ag NP)-loaded chitosan composites have numerous biomedical applications; however, fabricating uniform composite microparticles remains challenging. This paper presents a novel microfluidic approach for single-step and in situ synthesis of Ag NP-loaded chitosan microparticles. This proposed approach enables obtaining uniform and monodisperse Ag NP-loaded chitosan microparticles measuring several hundred micrometers. In addition, the diameter of the composites can be tuned by adjusting the flow on the microfluidic chip. The composite particles containing Ag NPs were characterized using UV–vis spectra and scanning electron microscopy-energy dispersive X-ray spectrometry data. The characteristic peaks of Ag NPs in the UV–vis spectra and the element mapping or pattern revealed the formation of nanosized silver particles. The results of antibacterial tests indicated that both chitosan and composite particles showed antibacterial ability, and Ag NPs could enhance the inhibition rate and exhibited dose-dependent antibacterial ability. Because of the properties of Ag NPs and chitosan, the synthesized composite microparticles can be used in several future potential applications, such as bactericidal agents for water disinfection, antipathogens, and surface plasma resonance enhancers

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Integrated process for the purification and immobilization of recombinant trehalose synthase for trehalose production

In this study an integrated process for the concomitant purification and immobilization of recombinant Picrophilus torridus trehalose synthase for the synthesis of trehalose was reported. A highly porous crosslinked polystyrene divinylbezene-based metal chelator was used for the purification and immobilization of the poly(His)-tagged enzyme. While the Cu(II)-loaded adsorbent showed the highest protein adsorption capacity, 5.39 0.03 mg protein/g, the Co(II)-loaded adsorbent exhibited the highest specificity for the adsorption of the poly(His)-tagged trehalose synthase, giving a specific activity of 3.98 0.50 U/mg protein, more than fourfold higher than that of the Cu(II)-loaded adsorbent. No significant differences in optimal operation pH, temperature, and thermostability were observed upon immobilization. Under optimal reaction conditions, a trehalose conversion yield of 64.1% was obtained within 6 h. A residual activity of approximately 80% was maintained after 24 cycles in a repeated-batch operation. The decline in residual activity was primarily due to the desorption of the recombinant trehalose synthase. The proposed integrated approach for enzyme purification and immobilization with the metal chelator is promising for the development of industrial processes for trehalose production