| 1. |
- Gil-Ramírez, Alicia, et al.
(författare)
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Purification of Natural Products by Selective Precipitation Using Supercritical/Gas Antisolvent Techniques (SAS/GAS)
- 2021
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Ingår i: Separation and Purification Reviews. - : Informa UK Limited. - 1542-2119 .- 1542-2127. ; 50:1, s. 32-52
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Forskningsöversikt (refereegranskat)abstract
- Supercritical fluids offer considerable advantages for the isolation of natural products. Supercritical fluids can be used as antisolvents to precipitate selectively target compounds from a mixture and to remove impurities by the Supercritical Antisolvent technique (SAS). The present decade has experienced a considerable increase in the number of publications that apply this technique to natural extracts, especially for the isolation of polyphenols and carotenoids from plants and microalgae. However, the lack of a clear terminology and purpose adds confusion to the topic. The proposed review aims at defining a research field that consists in applying SAS to natural extracts for the purification of target compounds. To do so, we trace back the origin of the field, discuss the different terminology used to refer to such processes, and suggest appropriate terms for the process and for reported results. This work explores the scope of the topic by compiling all works published to date from a scattered literature, using all possible process terminologies for the search. The information given aims to highlight the most promising applications explored so far and possibly inspire further research.
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| 2. |
- Metsämuuronen, Sari, et al.
(författare)
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Natural organic matter removal from drinking water by membrane technology
- 2014
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Ingår i: Separation and Purification Reviews. - : Informa UK Limited. - 1542-2119 .- 1542-2127. ; 43:1, s. 1-61
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Tidskriftsartikel (refereegranskat)abstract
- Aquatic natural organic matter (NOM) is a heterogeneous mixture of biopolymers and their degradation products that cause harmful by-products during drinking water production. The great variability in NOM composition makes it difficult to completely remove from drinking water by any single technique. The current paper reviews the NOM removal by micro-, ultra- and nanofiltration and by hybrid processes combining membrane techniques with other unit processes: coagulation, adsorption, and oxidation, and by membrane bioreactors.
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| 3. |
- Xie, Shao-Hua, et al.
(författare)
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Association between levels of sex hormones and risk of esophageal adenocarcinoma and Barrett’s esophagus
- 2019
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Ingår i: Clinical Gastroenterology and Hepatology. - Stockholm : Karolinska Institutet, Dept of Molecular Medicine and Surgery. - 1542-3565. ; 18:12, s. 2701-
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Esophageal adenocarcinoma (EAC) occurs most frequently in men. We performed a Mendelian randomization analysis to investigate whether genetic factors that regulate levels of sex hormones associated with risk of EAC or Barrett’s esophagus (BE). Methods: We conducted a Mendelian randomization analysis using data from patients with EAC (n=2488) or BE (n=3247) and control participants (n=2127), included in international consortia of genome-wide association studies in Australia, Europe, and North America. Genetic risk scores or single nucleotide variants were used as instrumental variables for 9 specific sex hormones. Logistic regression provided odds ratios (ORs) with 95% CIs. Results: Higher genetically predicted levels of follicle stimulating hormones were associated with increased risks of EAC and/or BE in men (OR, 1.14 per allele increase; 95% CI, 1.01- 1.27) and in women (OR, 1.28; 95% CI, 1.03-1.59). Higher predicted levels of luteinizing hormone were associated with a decreased risk of EAC in men (OR, 0.92 per standard deviation increase; 95% CI, 0.87-0.99) and in women (OR, 0.93; 95% CI, 0.79-1.09), and decreased risks of BE (OR, 0.88; 95% CI, 0.77-0.99) and EAC and/or BE (OR, 0.89; 95% CI, 0.79-1.00) in women. We found no clear associations for other hormones studied, including sex hormone-binding globulin, dehydroepiandrosterone sulphate, testosterone, dihydrotestosterone, estradiol, progesterone, or free androgen index. Conclusions: In a Mendelian randomization analysis of data from patients with EAC or BE, we found an association between genetically predicted levels of follicle stimulating and luteinizing hormones and risk of BE and EAC.
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| 4. |
- Xiarchos, I, et al.
(författare)
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Polymeric ultrafiltration membranes and surfactants.
- 2003
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Ingår i: Separation and Purification Reviews. - 1542-2127. ; 32:2, s. 215-278
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Forskningsöversikt (refereegranskat)abstract
- Surfactants have been extensively used in ultrafiltration processes such as membrane cleaning,removal of surfactants or other organic toxic compounds and metal ions from solutions and estimation of interactions at surfactant and membrane interface. The aim of this review is to present the possibilities that arise from the data reported in the literature on the field of ultrafiltration (UF) membranes and surfactants. This data is classified into five groups and a brief description of each article is given. Pretreatment of membranes with surfactant solutions can lead to performance increase of UF process. By Micellar-Enhanced Ultrafiltration the separation of low molecular weight toxic substances and heavy metals is possible, extending the applications of conventional UF (e.g. separation of proteins). Through estimation of the type of interactions on membrane surface with surfactants the prediction of retention and removal of small size substances, the prevention of fouling, the modification of surfactant-membrane system, the design of new surfactant-membrane system could be achieved. Finally economical aspects of UF-surfactant processes are given.
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| 5. |
- Wang, Haijuan, et al.
(författare)
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Modelling of Physico-Chemical Phenomena between Gas inside a Bubble and Liquid Metal during Injection of Oxidant Gas
- 2010
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Ingår i: International Journal of Chemical Reactor Engineering. - : Walter de Gruyter GmbH. - 1542-6580. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Gas liquid reactors are extensively used in many metallurgical processes involving the refining of liquid metals. In these processes, reactions leading to the oxidation of various solutes in liquid metal often compete with each other, which ultimately determine the liquid metal composition. In the present paper, a model has been proposed to simulate the evolution of solute contents in a metallic melt considering mass transfer of solutes in the melt in the vicinity of the bubble, equilibrium at the gas-metal interface and gas composition evolution in the bubble during its ascent through the melt. The composition of solutes at the metal-gas interface in principle can be altered by changing the injected gas composition.The model was applied to the case of oxygen injection through a lance into liquid steel-containing C and Cr, aiming sufficient decarburization without much oxidation of Cr to the slag. The Cr loss to the slag by oxidation is generally much more than that expected based on equilibrium thermodynamics applied to the bulk metal and gas. The actual Cr loss, as shown by the present model, is determined by the composition of solutes at the metal-gas interface rather than in the bulk. The effect of change of the partial pressure of oxygen in the bubble by replacing oxygen by carbon dioxide in the injected gas and the corresponding evolution of C and Cr contents in the melt was simulated. Some preliminary experiments were conducted to validate the model predictions. The frame work of the model is generic and can be extended to many gas-liquid metal reactors in liquid metal processing.
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