scholarly journals Viral Filtration: A Review of Current and Future Practices in Bioprocessing

2021 ◽  
Author(s):  
Sarah Johnson ◽  
Shuang Chen ◽  
Glen Bolton ◽  
Qi Chen ◽  
Scott Lute ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Test Methods ◽  
Retention Mechanism ◽  
Integrity Test ◽  
Drug Products ◽  
Safety Assurance ◽  
Recombinant Therapeutic Protein ◽  
History Of ◽  
Filtration Step ◽  
Biotechnology Products

For drug products manufactured in mammalian cells, safety assurance practices are needed during production to assure that the final medicinal product is safe from the potential risk of viral contamination. Virus filters provide viral retention for a range of viruses through robust, size-based retention mechanism. Therefore, a viral filtration step is commonly utilized in a well-designed recombinant therapeutic protein purification process and is a key component in an overall strategy to minimize the risks of adventitious and endogenous viral particles during the manufacturing of biotechnology products. This review summarizes the history of viral filtration, currently available viral filters and prefilters, and viral filtration integrity test methods and study models. There is also discussion of current understanding and gaps with an eye toward future trends and emerging filtration technologies.

scholarly journals Characterization of Subtype H6 Avian Influenza A Viruses Isolated From Wild Birds in Poyang Lake, China

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhimin Wan ◽  
Qiuqi Kan ◽  
Zhehong Zhao ◽  
Hongxia Shao ◽  
Thomas J. Deliberto ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Avian Influenza ◽  
Mammalian Cells ◽  
Influenza A ◽  
Poyang Lake ◽  
Wild Birds ◽  
Mouse Lung ◽  
Influenza A Viruses ◽  
Domestic Poultry ◽  
History Of

Subtype H6 avian influenza A viruses (IAVs) are enzootic and genetically diverse in both domestic poultry and wild waterfowl and may cause spillovers in both pigs and humans. Thus, it is important to understand the genetic diversity of H6 IAVs in birds and their zoonotic potential. Compared with that in domestic poultry, the genetic diversity of H6 viruses in wild birds in China has not been well-understood. In this study, five H6 viruses were isolated from wild birds in Poyang Lake, China, and genetic analyses showed that these isolates are clustered into four genotypes associated with reassortments among avian IAVs from domestic poultry and wild birds in China and those from Eurasia and North America and that these viruses exhibited distinct phenotypes in growth kinetics analyses with avian and mammalian cells lines and in mouse challenge experiments. Of interest is that two H6 isolates from the Eurasian teal replicated effectively in the mouse lung without prior adaptation, whereas the other three did not. Our study suggested that there are variations in the mammalian viral replication efficiency phenotypic among genetically diverse H6 IAVs in wild birds and that both intra- and inter-continental movements of IAVs through wild bird migration may facilitate the emergence of novel H6 IAV reassortants with the potential for replicating in mammals, including humans. Continued surveillance to monitor the diversity of H6 IAVs in wild birds is necessary to increase our understanding of the natural history of IAVs.

scholarly journals Conserved function of the lysine-based KXD/E motif in Golgi retention for endomembrane proteins among different organisms

2015 ◽  
Vol 26 (23) ◽  
pp. 4280-4293 ◽  
Author(s):  
Cheuk Hang Woo ◽  
Caiji Gao ◽  
Ping Yu ◽  
Linna Tu ◽  
Zhaoyue Meng ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Transgenic Arabidopsis ◽  
Morphological Changes ◽  
Retention Mechanism ◽  
Loss Of Function ◽  
Expression Systems ◽  
Conserved Motif ◽  
Ultrastructural Studies ◽  
Golgi Retention

We recently identified a new COPI-interacting KXD/E motif in the C-terminal cytosolic tail (CT) of Arabidopsis endomembrane protein 12 (AtEMP12) as being a crucial Golgi retention mechanism for AtEMP12. This KXD/E motif is conserved in CTs of all EMPs found in plants, yeast, and humans and is also present in hundreds of other membrane proteins. Here, by cloning selective EMP isoforms from plants, yeast, and mammals, we study the localizations of EMPs in different expression systems, since there are contradictory reports on the localizations of EMPs. We show that the N-terminal and C-terminal GFP-tagged EMP fusions are localized to Golgi and post-Golgi compartments, respectively, in plant, yeast, and mammalian cells. In vitro pull-down assay further proves the interaction of the KXD/E motif with COPI coatomer in yeast. COPI loss of function in yeast and plants causes mislocalization of EMPs or KXD/E motif–containing proteins to vacuole. Ultrastructural studies further show that RNA interference (RNAi) knockdown of coatomer expression in transgenic Arabidopsis plants causes severe morphological changes in the Golgi. Taken together, our results demonstrate that N-terminal GFP fusions reflect the real localization of EMPs, and KXD/E is a conserved motif in COPI interaction and Golgi retention in eukaryotes.

scholarly journals NON-MEDICAL MASKS: OPPORTUNITIES FOR STANDARDS EDUCATION AND ONLINE DESIGN PROJECTS

2021 ◽  
Author(s):  
David Torvi
Keyword(s):  
Engineering Students ◽  
Water Resistance ◽  
Test Methods ◽  
Standard Test ◽  
Online Course ◽  
History Of ◽  
Design Projects ◽  
Online Design ◽  
Standard Development

While engineering students gain some experience in the use of codes and standards, some may not be exposed to the process used to develop standards, or the history of individual standards. A number of resources on standard development are available to instructors, and knowing the history of a standard will aid in understanding its potential limitations when used in design. This paper will outline how the process of developing standard test methods for non-medical masks during the COVID-19 pandemic can be used as a case study in design courses.  Potential online projects and assignments related to testing of these masks are described, including considerations of material performance, comfort and functional fit, along with examples of analysis that students could perform.  Sample fabric tests that use readily-available supplies to measure water resistance are described to illustrate how assignments and projects could be completed by studentsremotely in an online course.

scholarly journals A Portable System for the Evaluation of the Degree of Pollution of Transmission Line Insulators

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6625
Author(s):  
Lucas de Paula Santos Petri ◽  
Emanuel Antonio Moutinho ◽  
Rondinele Pinheiro Silva ◽  
Renato Massoni Capelini ◽  
Rogério Salustiano ◽  
...  
Keyword(s):  
Fuzzy Inference ◽  
Electric Utility ◽  
Test Methods ◽  
Raspberry Pi ◽  
Pollution Level ◽  
Convolutional Network ◽  
Inference System ◽  
History Of ◽  
Portable System ◽  
Severity Degree

Surface pollution is a major cause of partial discharges in high voltage insulators in coastal cities, leading to degradation of their surface and accelerating their aging process, which may cause visible arcing, flashovers and system faults. Thus, this work provides a methodology for the assessment of the condition of insulators based on an instrument which generates a severity degree to help the electric utility team schedule maintenance routines for the structures that really need it. The instrument uses a Raspberry Pi board as the processing core, a PicoScope oscilloscope for the data acquisition and an antenna as a partial discharge sensor. The algorithms are implemented in Python, and use artificial intelligence tools, such as a convolutional network and a fuzzy inference system. Laboratory test methods for the simulation of the field pollution conditions were successfully used for the validation of the instrument, which showed a good correlation between the pollution level and the severity degree generated. In addition to that, field collected data were also used for the evaluation of the proposed severity degree, which is demonstrated to be consistent when compared with the utility’s reports and the history of the selected areas from where data were collected.

scholarly journals Characterization of Historic Binders and Stones of a Ruined Medieval Church (Hungary)

2020 ◽  
Author(s):  
Zsuzsanna Kósa ◽  
Ákos Török
Keyword(s):  
Moisture Content ◽  
Construction Materials ◽  
Selective Dissolution ◽  
Test Methods ◽  
Schmidt Hammer ◽  
Fine Grained ◽  
Medieval Church ◽  
History Of ◽  
Non Destructive

Construction materials of a partly ruined Medieval church of Central Hungary were studied in details to assess its conditions and to obtain information on the phases of construction. At first, digital images were taken to create a 3D model of the remaining walls. The material properties were measured in situ using non-destructive test methods. Strength parameters of stone and render were assessed by Schmidt hammer, while moisture content was measured by a portable moisture meter. According to lithological descriptions and thin-section analyses limestone prevail in the monument. The most common Miocene limestone is represented by various lithologies, such as cemented macro porous limestone, fine-grained porous limestone, oolitic limestone and bioclastic limestone. Mesozoic micritic well cemented limestone and Tertiary limonitic sandstone were also identified at the ruins. The most common weathering forms are selective dissolution, multiple flaking and biological colonisation. Renders used in the structure represents the long history of the structure from Medieval lime-based mortars to Portland cement containing latest applications. The former one is composed of quartz send in lime binder. According to Schmidt hammer tests, the rebound values of the replacement stone is higher than that of the original porous limestone. There is a distinct difference in the moisture content of the stone and render. Orientation/exposure of the wall also influences the moisture content. The gathered information allows for designing better repair methods and helps in the planning of the maintenance of the medieval stone heritage.

A Bio-Inspired Phenomena in Cementitious Materials

2016 ◽  
pp. 220-246
Author(s):  
Onur Üzüm ◽  
Özge Andiç Çakır
Keyword(s):  
Cementitious Materials ◽  
Test Methods ◽  
Measurement Methods ◽  
Full Detail ◽  
Self Healing ◽  
History Of ◽  
Definition Of

In this chapter, a deep analyse of a bio-inspired phenomenon starting with broad definitions of included mechanisms is provided. Since establishing an understanding starts with drawing the boundaries of a concept, foremost the definition of related terms are discussed in detail. Afterwards, the importance and history of self-healing phenomenon including the relevant concepts are presented. In order to facilitate the classification, the relevant sub-chapters present two main classes namely autogenic and autonomic healing. Nevertheless, the concepts and mechanisms under these two main topics are also discussed in detail. Finally, evaluation of self-healing mechanisms, tests conducted to determine whether self-healing took place, the indicators of measurement methods, using materials and test methods are given in full detail.

scholarly journals Emergence of Mammalian Cell-Adapted Vesicular Stomatitis Virus from Persistent Infections of Insect Vector Cells

2007 ◽  
Vol 81 (12) ◽  
pp. 6664-6668 ◽  
Author(s):  
Isabel S. Novella ◽  
Bonnie E. Ebendick-Corpus ◽  
Selene Zárate ◽  
Eric L. Miller
Keyword(s):  
Mammalian Cell ◽  
Vesicular Stomatitis Virus ◽  
Mammalian Cells ◽  
Sand Fly ◽  
Insect Vector ◽  
Low Frequencies ◽  
Persistent Infections ◽  
Unrelated Sequence ◽  
History Of ◽  
Vesicular Stomatitis

ABSTRACT Arboviruses (arthropod-borne viruses) represent quintessential generalists, with the ability to infect and perform well in multiple hosts. However, antagonistic pleiotropy imposed a cost during the adaptation to persistent replication of vesicular stomatitis virus in sand fly cells and resulted in strains that initially replicated poorly in hamster cells, even when the virus was allowed to replicate periodically in the latter. Once a debilitated strain started replicating continuously in mammalian cells, fitness increased significantly. Fitness recovery did not entail back mutations or compensatory mutations, but instead, we observed the replacement of persistence-adapted genomes by mammalian cell-adapted strains with a full set of new, unrelated sequence changes. These mammalian cell-adapted genomes were present at low frequencies in the populations with a history of persistence for up to a year and quickly became dominant during mammalian infection, but coexistence was not stable in the long term. Periodic acute replication in mammalian cells likely contributed to extending the survival of minority genomes, but these genomes were also found in strictly persistent populations.

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