Sökresultat

Filtyp

Din sökning på "*" gav 542639 sökträffar

Processing of high entropy alloys with exceptionally good high temperature oxidation properties

The invention relates to High Entropy Alloys for high hardness and high temperature oxidation resistant applications. A new processing method has been developed to prepare the said alloys containing equiatomic ratios of Al, Co, Cr, Fe and Ni to obtain a nanocrystalline phases directly after high energy ball milling. Cr7C3 precipitates having size less than 15 nm are formed through an in-situ react

Effects of absorbent treatment on the purification of paclitaxel from cell cultures of Taxus chinensis and yew tree

A new synthetic absorbent, sylopute was applied for the purification of paclitaxel from plant cell cultures and yew tree. There was selective absorption of impurities in the treatment of sylopute. Therefore, higher purity paclitaxel could be obtained simply in the following process with a higher yield than with active clay or activated carbon. The purity of crude paclitaxel after sylopute treatmen

Why review papers get rejected : common pitfalls and how to avoid them

PurposeIn this paper, we discuss common pitfalls in producing review articles for publication in academic journals, offering guidance to minimize rejection rates. We highlight the dual core features of systematicity (i.e. rigor and transparency) and generativity (i.e. advancing knowledge) in review papers. Thereby, we aim to help researchers deal with the abundance of guidelines and create publish

Expression and purification of a recombinant buforin derivative from Escherichia coli

An Escherichia coli expression system was constructed for production of a recombinant antimicrobial peptide buforin derivative named buforin IIb and a large-scale process of cultivation and purification was also developed. Inclusion bodies of fusion proteins containing recombinant buforin IIb were released from high-density-cultured cells by high-pressure homogenization. The inclusion bodies

Efficient purification and morphology characterization of paclitaxel from cell cultures of Taxus chinensis

Paclitaxel was purified from cell cultures of Taxus chinensis by a combination of extraction, low-pressure chromatography, precipitation and HPLC. A crude extract (purity 6.9%) was obtained by methanol extraction of plant cell cultures, followed by liquid–liquid extraction using dichloromethane. The extract was purified to greater than 32% with a 97% step yield by low-pressure chromatography. A

Desorption of fructose from a packed column to an oleic acid/fructose oleate mixture for employment in a bioreactor system

Adsorption isotherms for a packed column consisting of fructose and silica gel in contact with a liquid phase consisting of oleic acid and fructose mono- and di-oleate at 65 °C were determined to assist the column’s utilization in a bioreactor system for the solvent-free lipase-catalyzed synthesis of saccharide ester biosurfactants. The liquid-phase fructose content was very low, ranging from 0.00

Designs of bioreactor systems for solvent-free lipase-catalyzed synthesis of fructose–oleic acid esters

Fructose–oleic acid esters, biodegradable, biocompatible and biobased surfactants and value-added products were synthesized under solvent-free conditions at 65 °C in stirred-batch mode and using several different bioreactor systems. For a stirred-tank bioreactor (STBR) using fed-batch fructose addition and 5.0 wt.% immobilized Rhizomucor miehei lipase (Lipozyme® IM, Novozymes, Franklinton, NC), th

Femtosecond energy transfer within the LH2 peripheral antenna of the photosynthetic purple bacteria Rhodobacter sphaeroides and Rhodopseudomonas palustris LL

The ultrafast energy transfer among the pigments of the B800-850 membrane antenna pigment-protein complex of the photosynthetic purple bacteria Rhodobacter sphaeroides and Rhodopseudomonas palustris LL has been studied with ≈ 100 fs tunable infrared pulses at room temperature and 77 K. It is shown that the B800→B850 transfer time is similar in both species and occurs with a characteristic time con

Effect of Cr and Al on phase constitution and high temperature oxidation behavior of Al-Co-Cr-Fe-Ni high entropy alloys

In this thesis, the inherent oxidation resistance of Al-Co-Cr-Fe-Ni based high entropy alloys have been remarkably enhanced by increasing the grain boundary area and recognizing the influence of the in situ Al2O3 nano-dispersoids. Isothermal continuous oxidation test based on thermogravimetric analysis (TGA) as well as extensive furnace oxidation, were conducted in the elevated temperature range o

The role of βArg-10 in the B800 bacteriochlorophyll and carotenoid pigment environment within the light-harvesting LH2 complex of Rhodobacter sphaeroides

Previous work has suggested that the βArg-10 residue forms part of the binding site for the B800 bacteriochlorophyll in the LH2 complex of Rhodobacter sphaeroides [Crielaard, W., Visschers, R. W., Fowler, G. J. S., van Grondelle, R., Hellingwerf, K. J., Hunter, C. N. (1994) Biochim. Biophys. Acta 1183, 473−482], and this is consistent with the X-ray crystallographic data that have been subsequent

Our journey toward implementation of digital breast tomosynthesis in breast cancer screening : the Malmö Breast Tomosynthesis Screening Project

Purpose: The purpose is to describe the Malmö Breast Tomosynthesis Screening Project from the beginning to where we are now, and thoughts for the future. Approach: In two acts, we describe the efforts made by our research group to improve breast cancer screening by introducing digital breast tomosynthesis (DBT), all the way from initial studies to a large prospective population-based screening tri

Megavoltage photon FLASH for preclinical experiments

Background: FLASH radiotherapy using megavoltage (MV) photon beams should enable greater therapeutic efficacy, target deep seated tumors, and provide insights into mechanisms within FLASH. Purpose: In this study, we aim to show how to facilitate ultra-high dose rates (FLASH) with MV photons over a field size of 12–15 mm, using a 6 MeV (nominal) preclinical electron linear accelerator (linac). Our

From farm to table : uncovering narratives of agency and responsibility for change among actors along agri-food value chains in Germany

Given the complex nature of agri-food value chains and related sustainability challenges, the question arises who has the agency and responsibility to address these challenges and facilitate systemic change. We address this question through a mixed method approach and examine experiences with agriculture among different actors along the agricultural value chains in Germany. Based on this, we explo

Anti-HSP90α IgG may protect against antiphospholipid syndrome in systemic lupus erythematosus by reducing platelet activation

Natural autoantibodies (NAAbs) are immunoglobulins generated in the absence of antigen provocation, with no inherent pathogenic effect, but instead involved in maintaining immune homeostasis. We aimed to evaluate the implication of immunoglobulin G (IgG) antibodies against heat shock protein 90α (HSP90α) in systemic lupus erythematosus (SLE) patients, focusing on how those NAAbs may interfere with

Artificial intelligence, hiring and employment : job postings evidence from Sweden

This paper investigates the impact of artificial intelligence (AI) on hiring and employment, using the universe of job postings published by the Swedish Public Employment Service from 2014 to 2022 and full-population administrative data for Sweden. We exploit a detailed measure of AI exposure according to occupational content and find that establishments exposed to AI are more likely to hire AI wo

Persistence of Ce3+ species on the surface of ceria during redox cycling : a modulated chemical excitation investigation

Operando resonant photoelectron spectroscopy (RPES) combined with modulated chemical excitation revealed the dynamic evolution of Ce3+/Ce4+ redox states at the surface of CeO2 during the CO oxidation reaction. Using alternating CO and O2 pulses as chemically modulated signals, we monitored the surface states in the valence band region, unveiling the evolution of electronic structure during the cat

Excited states of carotenoid in LH2 : An ab initio study

In order to understand the origin of ultrafast carotenoid bandshifts upon photoexcitation of bacteriochlorophyll (BChl) molecules in antenna complexes of photosynthetic purple bacteria, we have performed sa-CASSCF(8,7)/6-31G (and 6-31G*) calculations for the low-lying excited states of the carotenoid rhodopin glucoside (RG). The LH2 environment was simulated via atomic point charges to represent t

Weed–crop competition under improved nutrient management reveals trade-off between yields and weed diversity in organic farming

In the pursuit of more sustainable agriculture, weeds play a dual role by threatening crop production and simultaneously contributing to farmland biodiversity. Management actions such as the use of fertilisers (fertilisation) may change weed abundance and community composition with consequences for both weed–crop competition and biodiversity. Alleviating the balance between yield and biodiversity

Dynamics of energy transfer in the LH2 antenna complex of the purple bacterium Rhodobacter sphaeroides

Transient absorption spectra and kinetics are used for detailed studies of energy transfer dynamics within the B850 ring of the LH2 antenna of the purple bacterium Rb. sphaeroides. The initial exciton relaxation was found to occur within the first 100 fs and no temperature dependence of this process was observed. Trnsient abcorption spectra of the LH2 antenna complex at 6 K revealed a new spectral