A critical review in recent progress of hollow fiber membrane contactors for efficient CO2 separations

Among wide range of membrane-based operations, membrane contactors, as they reify comparatively modern membrane-based mechanism are gaining quite an attention in both pilot and industrial scales. In recent literature, carbon capture is one of the most researched applications of membrane contactors. Membrane contactors have the potential to minimize the energy consumption and capital cost of traditional CO₂ absorptions columns. In a membrane contactor, CO₂ regeneration can take place below the solvent boiling point, resulting into lower consumption of energy. Various polymeric as well as ceramic membrane materials have been employed in gas liquid membrane contactors along with several solvents including amino acids, ammonia, amines etc. This review article provides detailed introduction of membrane contactors in terms of CO₂ removal. It also discusses that the main challenge that is faced by membrane contactors is membrane pore wetting caused by solvent that in turn can reduce the mass transfer coefficient. Other potential challenges such as selection of suitable solvent and membrane pair as well as fouling are also discussed in this review and are followed by potential ways to reduce them. Furthermore, both membrane gas separation and membrane contactor technologies are analysed and compared in this study on the basis of their characteristics, CO₂ separation performances and techno economical transvaluation. Consequently, this review provides an opportunity to thoroughly understand the working principle of membrane contactors along its comparison with membrane-based gas separation technology. It also provides a clear understanding of latest innovations in membrane contactor module designs as well as challenges encountered by membrane contactors along with possible solutions to overcome these challenges. Finally, semi commercial and commercial implementation of membrane contactors has been highlighted.

Oilfield-produced water treatment using conventional and membrane-based technologies for beneficial reuse: A critical review

Oilfield produced water (OPW) is one of the most important by-products, resulting from oil and gas exploration. The water contains a complex mixture of organic and inorganic compounds such as grease, dissolved salt, heavy metals as well as dissolved and dispersed oils, which can be toxic to the environment and public health. This article critically reviews the complex properties of OPW and various technologies for its treatment. They include the physico-chemical treatment process, biological treatment process, and physical treatment process. Their technological strengths and bottlenecks as well as strategies to mitigate their bottlenecks are elaborated. A particular focus is placed on membrane technologies. Finally, further research direction, challenges, and perspectives of treatment technologies for OPW are discussed. It is conclusively evident from 262 published studies (1965-2021) that no single treatment method is highly effective for OPW treatment as a stand-alone process however, conventional membrane-based technologies are frequently used for the treatment of OPW with the ultrafiltration (UF) process being the most used for oil rejection form OPW and oily waste water. After membrane treatment, treated effluents of the OPW could be reused for irrigation, habitant and wildlife watering, microalgae production, and livestock watering. Overall, this implies that target pollutants in the OPW samples could be removed efficiently for subsequent use, despite its complex properties. In general, it is however important to note that feed quality, desired quality of effluent, cost-effectiveness, simplicity of process are key determinants in choosing the most suitable treatment process for OPW treatment.

Participation of two fusion peptides in measles virus-induced membrane fusion: emerging similarity with other paramyxoviruses

Paramyxoviruses penetrate into their host cells by fusing their membranes with the plasma membrane. The hydrophobic N terminus of their F1 protein, termed the 'fusion peptide', is thought to be responsible for this process. Recently, an additional internal fusion peptide, homologous in sequence to the N-terminal fusion peptide of HIV-1, was identified in the Sendai virus F1 protein. Here, we investigated whether the presence of an additional internal fusion peptide is a general feature of paramyxoviridae. To this end, we synthesized and structurally and functionally characterized three peptides: (i) MV-197, which corresponds to an internal segment of the F1 protein of the measles virus (amino acids 197-225), homologous in location but not in sequence to the internal fusion peptide of the Sendai virus, (ii) Mu-MV-197, a randomized version of MV-197, and (iii) the 33 amino acid N-terminal fusion peptide of the measles virus. Remarkably, only MV-197 was highly fusogenic toward large unilamellar vesicles composed of either zwitterionic (phosphatidylcholine or phosphatidylcholine/sphingomyelin/cholesterol, a composition similar to that of human cell membranes) or negatively charged phospholipids. Binding experiments, circular dichroism spectroscopy in phospholipid membranes, and homo energy-transfer studies with fluorescently labeled peptides revealed that MV-197 adopts a predominant alpha-helical structure and shares properties similar to those reported for known fusion peptides. These results suggest that the presence of two fusion peptides in the F1 protein is a general feature of paramyxoviruses.

Levels of cadmium in kidney and liver tissues among a Canadian population (province of Québec)

In an exploratory study, levels of cadmium in whole-kidney and liver tissues of 314 subjects from the general population of the province of Quebec (Canada) were measured postmortem. Frequency distributions of cadmium concentrations were lognormal. As reported in similar studies, age and especially smoking habits were the main variables affecting cadmium concentrations. The geometric mean of whole kidney concentrations (wet weight) was 17.62 microg/g, with a minimum concentration of 2.25 microg/g and a maximum of 100.61 microg/g. Mean concentrations of cadmium in kidneys increased with age, reaching a plateau in the group 50 to 59 yr (29.49 microg/g), and falling slowly thereafter.

[Toward a demo-anthropological perspective on nuptiality and its relationship with new reproductive patterns: consideration of a study carried out in the area surrounding Zacatepec, Morelos]

"The research is based on a study carried out between 1989 and 1991 in the three rural communities in the state of Morelos [Mexico] that included a socio-demographic survey and interviews. The methodological goal of the authors is to view nuptiality from demographic and anthropological standpoints.... The authors seek to pinpoint the elements that account for changes that have taken place in nuptiality, as well as to identify the impact of these changes on [descendants]." (SUMMARY IN ENG)

[A comparative socio-demographic study of nuptiality in two states: Aguascalientes and Veracruz]

"In this article, nuptiality is studied as a demographic and social phenomenon.... The study focuses on two states of [Mexico]: Aguascalientes and Veracruz, where the author analyzes the formation of couples, the social norms which determine marriage behavior patterns, and the interaction between marriage and reproductive behavior patterns....[The study] includes a description of the characteristics and patterns of unions in the two regions based on data from the 1982 'Encuesta Nacional Demografica' (National Demographic Survey) and on published studies on the subject." (SUMMARY IN ENG)

How doctors learn in a Balint group

The discussions are led by a psychoanalyst, or someone in touch with the approach fostered by psychoanalysis, and the group is helped to develop an atmosphere of tolerance and safety. Participants are thus able to discuss cases that represent the personal difficulties they are currently experiencing in their daily work. This report is about one group whose members agreed to allow the process of their work to be studied. It describes how they went about learning from their daily experience with patients by using the group to work through their difficulties. It also describes methods used to assess the quality of learning and the changes in personal attitudes. A Balint group has a safe and defined mode of working but no specific agenda, save that provided by the personal cases presented by those who come regularly to its sessions. This study aims to describe the kind of experience such a group can offer to intending participants.