scholarly journals Physiological Microenvironmental Conditions in Different Scalable Culture Systems for Pluripotent Stem Cell Expansion and Differentiation

2019 ◽  
Vol 13 (1) ◽  
pp. 41-54
Author(s):  
Fuad G. Torizal ◽  
Ikki Horiguchi ◽  
Yasuyuki Sakai
Keyword(s):  
Culture System ◽  
Large Scale ◽  
Culture Conditions ◽  
High Yield ◽  
Culture Systems ◽  
Physiological Conditions ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Recent Developments ◽  
Cell Propagation

Human Pluripotent Stem Cells (PSCs) are a valuable cell type that has a wide range of biomedical applications because they can differentiate into many types of adult somatic cell. Numerous studies have examined the clinical applications of PSCs. However, several factors such as bioreactor design, mechanical stress, and the physiological environment have not been optimized. These factors can significantly alter the pluripotency and proliferation properties of the cells, which are important for the mass production of PSCs. Nutritional mass transfer and oxygen transfer must be effectively maintained to obtain a high yield. Various culture systems are currently available for optimum cell propagation by maintaining the physiological conditions necessary for cell cultivation. Each type of culture system using a different configuration with various advantages and disadvantages affecting the mechanical conditions in the bioreactor, such as shear stress. These factors make it difficult to preserve the cellular viability and pluripotency of PSCs. Additional limitations of the culture system for PSCs must also be identified and overcome to maintain the culture conditions and enable large-scale expansion and differentiation of PSCs. This review describes the different physiological conditions in the various culture systems and recent developments in culture technology for PSC expansion and differentiation.

scholarly journals Electrooxidation enables highly regioselective dearomative annulation of indole and benzofuran derivatives

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kun Liu ◽  
Wenxu Song ◽  
Yuqi Deng ◽  
Huiyue Yang ◽  
Chunlan Song ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Thermal Conditions ◽  
Kinetic Studies ◽  
Added Value ◽  
High Yield ◽  
Paramagnetic Resonance ◽  
Good Efficiency ◽  
Rate Determining Step ◽  
Wide Range

AbstractThe dearomatization of arenes represents a powerful synthetic methodology to provide three-dimensional chemicals of high added value. Here we report a general and practical protocol for regioselective dearomative annulation of indole and benzofuran derivatives in an electrochemical way. Under undivided electrolytic conditions, a series of highly functionalized five to eight-membered heterocycle-2,3-fused indolines and dihydrobenzofurans, which are typically unattainable under thermal conditions, can be successfully accessed in high yield with excellent regio- and stereo-selectivity. This transformation can also tolerate a wide range of functional groups and achieve good efficiency in large-scale synthesis under oxidant-free conditions. In addition, cyclic voltammetry, electron paramagnetic resonance (EPR) and kinetic studies indicate that the dehydrogenative dearomatization annulations arise from the anodic oxidation of indole into indole radical cation, and this process is the rate-determining step.

scholarly journals Biosolar cells: global artificial photosynthesis needs responsive matrices with quantum coherent kinetic control for high yield

2015 ◽  
Vol 5 (3) ◽  
pp. 20150014 ◽  
Author(s):  
R. L. Purchase ◽  
H. J. M. de Groot
Keyword(s):  
The Netherlands ◽  
Large Scale ◽  
Artificial Photosynthesis ◽  
High Efficiency ◽  
Raw Material ◽  
High Yield ◽  
Photosynthesis Research ◽  
Advantages And Disadvantages ◽  
Artificial Photosynthetic ◽  
Carbon Based

This contribution discusses why we should consider developing artificial photosynthesis with the tandem approach followed by the Dutch BioSolar Cells consortium, a current operational paradigm for a global artificial photosynthesis project. We weigh the advantages and disadvantages of a tandem converter against other approaches, including biomass. Owing to the low density of solar energy per unit area, artificial photosynthetic systems must operate at high efficiency to minimize the land (or sea) area required. In particular, tandem converters are a much better option than biomass for densely populated countries and use two photons per electron extracted from water as the raw material into chemical conversion to hydrogen, or carbon-based fuel when CO 2 is also used. For the average total light sum of 40 mol m −2 d −1 for The Netherlands, the upper limits are many tons of hydrogen or carbon-based fuel per hectare per year. A principal challenge is to forge materials for quantitative conversion of photons to chemical products within the physical limitation of an internal potential of ca 2.9 V. When going from electric charge in the tandem to hydrogen and back to electricity, only the energy equivalent to 1.23 V can be stored in the fuel and regained. A critical step is then to learn from nature how to use the remaining difference of ca 1.7 V effectively by triple use of one overpotential for preventing recombination, kinetic stabilization of catalytic intermediates and finally generating targeted heat for the release of oxygen. Probably the only way to achieve this is by using bioinspired responsive matrices that have quantum–classical pathways for a coherent conversion of photons to fuels, similar to what has been achieved by natural selection in evolution. In appendix A for the expert, we derive a propagator that describes how catalytic reactions can proceed coherently by a convergence of time scales of quantum electron dynamics and classical nuclear dynamics. We propose that synergy gains by such processes form a basis for further progress towards high efficiency and yield for a global project on artificial photosynthesis. Finally, we look at artificial photosynthesis research in The Netherlands and use this as an example of how an interdisciplinary approach is beneficial to artificial photosynthesis research. We conclude with some of the potential societal consequences of a large-scale roll out of artificial photosynthesis.

scholarly journals Composite Enclaves: Towards Disaggregated Trusted Execution

2021 ◽  
pp. 630-656
Author(s):  
Moritz Schneider ◽  
Aritra Dhar ◽  
Ivan Puddu ◽  
Kari Kostiainen ◽  
Srdjan Čapkun
Keyword(s):  
Case Studies ◽  
Large Scale ◽  
Trusted Computing ◽  
Design Time ◽  
Wide Range ◽  
Trusted Computing Base ◽  
Recent Developments ◽  
Configurable Hardware ◽  
Low Performance ◽  
Specialized Hardware

The ever-rising computation demand is forcing the move from the CPU to heterogeneous specialized hardware, which is readily available across modern datacenters through disaggregated infrastructure. On the other hand, trusted execution environments (TEEs), one of the most promising recent developments in hardware security, can only protect code confined in the CPU, limiting TEEs’ potential and applicability to a handful of applications. We observe that the TEEs’ hardware trusted computing base (TCB) is fixed at design time, which in practice leads to using untrusted software to employ peripherals in TEEs. Based on this observation, we propose composite enclaves with a configurable hardware and software TCB, allowing enclaves access to multiple computing and IO resources. Finally, we present two case studies of composite enclaves: i) an FPGA platform based on RISC-V Keystone connected to emulated peripherals and sensors, and ii) a large-scale accelerator. These case studies showcase a flexible but small TCB (2.5 KLoC for IO peripherals and drivers), with a low-performance overhead (only around 220 additional cycles for a context switch), thus demonstrating the feasibility of our approach and showing that it can work with a wide range of specialized hardware.

scholarly journals Impact of culture condition modulation on the high-yield, high-specificity and cost-effective production of terpenoids from microbial sources: A review

2020 ◽  
Author(s):  
Vibha Shukla ◽  
Suresh Chandra Phulara
Keyword(s):  
Physicochemical Parameters ◽  
High Specificity ◽  
Cost Effective ◽  
Fermentation Medium ◽  
Culture Conditions ◽  
High Yield ◽  
Native Form ◽  
Yield Production ◽  
Wide Range ◽  
The Impact

Recent years have seen a remarkable increase in the non-natural production of terpenoids from microbial route. This is due to the advancements in synthetic biology tools and techniques, which have overcome the challenges associated with the non-native production of terpenoids from microbial hosts. Although, microbes in their native form have ability to grow in wide range of physicochemical parameters such as, pH, temperature, agitation, aeration etc; however, after genetic modifications, culture conditions need to be optimized in order to achieve improved titers of desired terpenoids from engineered microbes. The physicochemical parameters together with medium supplements, such as, inducer, carbon and nitrogen source, and cofactor supply not only play an important role in high-yield production of target terpenoids from engineered host, but also reduce the accumulation of undesired metabolites in fermentation medium, thus facilitate product recovery. Further, for the economic production of terpenoids, the biomass derived sugars can be utilized together with the optimized culture conditions. In the present mini-review, we have highlighted the impact of culture conditions modulation on the high-yield and high-specificity production of terpenoids from engineered microbes. Lastly, utilization of economic feedstock has also been discussed for the cost-effective and sustainable production of terpenoids.

scholarly journals BNC Biosynthesis with Increased Productivity in a Newly Designed Surface Air-Flow Bioreactor

2020 ◽  
Vol 10 (11) ◽  
pp. 3850
Author(s):  
Izabela Cielecka ◽  
Małgorzata Ryngajłło ◽  
Stanisław Bielecki
Keyword(s):  
Mechanical Properties ◽  
Air Flow ◽  
Culture Conditions ◽  
Production Costs ◽  
High Yield ◽  
Flow Ratio ◽  
Culture Time ◽  
Wide Range ◽  
Burman Design ◽  
Plackett Burman Design

The application of bacterial cellulose (BNC) could be widely expanded if the production costs were reduced. This study aims to determine factors simultaneously affecting the yield and tensile strength of BNC in a newly designed surface air-flow bioreactor (SAF). For this purpose, a two-stage study was done. Firstly, the most important factors for high yield were determined based on the Plackett–Burman Design. Secondly, impact of the chosen variables on both responses was assessed in a wide range of factor values. The greatest influence on the yield and mechanical strength was proved for such factors as air-flow ratio, glucose concentration, and culture time. The productivity in a SAF bioreactor with controlled air-flow ratio was enhanced by 65%. In terms of mechanical properties, the stress of BNC membranes varied from 0.8 to 6.39 MPa depending on the culture conditions. The results of the performed tests make a useful basis for future optimizations.

scholarly journals Governance models for robotic process automation: The case of Nordea Bank

2020 ◽  
pp. 204388692093702
Author(s):  
Damian Kedziora ◽  
Esko Penttinen
Keyword(s):  
Large Scale ◽  
Business Processes ◽  
Process Automation ◽  
General Data Protection Regulation ◽  
Robotic Process Automation ◽  
Advantages And Disadvantages ◽  
Decision Points ◽  
Wide Range ◽  
External Reporting ◽  
Key Issues

The teaching case addresses the governance of robotic process automation at Nordea, a large banking group operating primarily in the Nordic region. Nordea has deployed numerous software robots, for a wide range of business processes, from transaction-processing work and both internal and external reporting all the way to interaction with end users in handling of General Data Protection Regulation (GDPR)-related queries. The scene is set with a meeting where three people discuss the current state of robotic process automation implementation at Nordea: Group Head of Robotics Agnieszka Belowska Gosławska, Head of Robotic Process Automation Operations Piotr Stolarczyk and Acting Head of Robotics Execution Jaroslaw Motylewski. The presentation outlines several governance-related issues and decision points that must be addressed in connection with any deployment of robotic process automation at somewhat large scale within a company. The key issues are related to the software’s development and maintenance, robotic process automation governance and IT infrastructure. Students who have worked through the case should be able to (1) describe archetypal and hybrid governance modes for robotic process automation and (2) evaluate their advantages and disadvantages for solid infrastructure and effective software development and maintenance.

Massive and Selective Ex Vivo Generation of Matured and Functional Human Red Blood Cells (RBC) from Hematopoietic Stem Cells of Diverse Origins: Towards the New Concept of “Cultured RBC”.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 379-379
Author(s):  
Luc Douay ◽  
Ladan Kobari ◽  
Helene Lapillonne ◽  
David Chalmers ◽  
Laurent Kiger ◽  
...  
Keyword(s):  
Large Scale ◽  
Ex Vivo ◽  
Erythroid Differentiation ◽  
Culture Conditions ◽  
Hematopoietic Stem ◽  
Human Red Blood Cells ◽  
Wide Range ◽  
Stromal Cell Line ◽  
A Cell ◽  
Free Media

Abstract We report a technological approach permitting, for the first time, the massive (up to 2x106-fold cell expansion) and selective (100%) ex vivo production of mature RBCs (cRBCs) starting from CD 34+ cells from peripheral blood (PB), bone marrow (BM) or cord blood (CB) into mature red cells in three steps: firstly, cell proliferation and erythroid differentiation were induced in serum free media supplemented with SCF, IL-3 and Epo for 8 days. Secondly, cells were co-cultured with additional Epo alone on either the murine MS-5 stromal cell line or human mesenchymal cells for 3 days. In the third step, all exogenous factors were withdrawn and cells were incubated on a simple stroma for 4 to 10 days. These cultured erythroid cells (reticulocytes and mature RBCs) displayed characteristics identical to those of native cells, in terms of MCV, MCH, MCHC, enzyme content (G6PD and PK) and deformability. The nature of the Hb produced depended on both the origin of the CD34+ cells and the culture conditions. cRBCs derived from PB or adult BM contained adult Hb (95±1%) whereas cRBCs derived from CB contained essentially HbF (64±13%). As for native RBCs, Hb was able to fix and release oxygen. CFSE-labelled-reticulocytes ex vivo generated from leukapheresis were injected into NOD-SCID mice. The transfused reticulocytes were found in the circulation to the same extent as native RBCs and fully matured into RBCs. This methodology is applicable for fundamental analysis of the mechanisms of terminal erythropoiesis and hemoglobin synthesis. Moreover, large scale cRBCs production could be possible with such a protocol. It can therefore be extrapolated to a wide range of clinical applications in the field of gene therapy, infectious diseases and particularly transfusion medicine with a pointed interest for the generation of a cell population homogeneous in age, thus achieving the new concept of cultured RBCs transfusion.

scholarly journals Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

2011 ◽  
Vol 7 ◽  
pp. 59-74 ◽  
Author(s):  
Carolin Fischer ◽  
Burkhard Koenig
Keyword(s):  
Large Scale ◽  
Standard Procedure ◽  
Bond Formation ◽  
Reaction Times ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
High Yield ◽  
Active Compounds ◽  
Advantages And Disadvantages ◽  
Ring Structures

N-Arylated aliphatic and aromatic amines are important substituents in many biologically active compounds. In the last few years, transition-metal-mediated N-aryl bond formation has become a standard procedure for the introduction of amines into aromatic systems. While N-arylation of simple aromatic halides by simple amines works with many of the described methods in high yield, the reactions may require detailed optimization if applied to the synthesis of complex molecules with additional functional groups, such as natural products or drugs. We discuss and compare in this review the three main N-arylation methods in their application to the synthesis of biologically active compounds: Palladium-catalysed Buchwald–Hartwig-type reactions, copper-mediated Ullmann-type and Chan–Lam-type N-arylation reactions. The discussed examples show that palladium-catalysed reactions are favoured for large-scale applications and tolerate sterically demanding substituents on the coupling partners better than Chan–Lam reactions. Chan–Lam N-arylations are particularly mild and do not require additional ligands, which facilitates the work-up. However, reaction times can be very long. Ullmann- and Buchwald–Hartwig-type methods have been used in intramolecular reactions, giving access to complex ring structures. All three N-arylation methods have specific advantages and disadvantages that should be considered when selecting the reaction conditions for a desired C–N bond formation in the course of a total synthesis or drug synthesis.

scholarly journals Optimized culture systems for the preimplantation ICR mouse embryos with wide range of EDTA concentrations

2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Seema Thapa ◽  
Seung Hee Kang ◽  
Yun Seok Heo
Keyword(s):  
Large Volume ◽  
Culture System ◽  
Ethylenediaminetetraacetic Acid ◽  
Culture Media ◽  
Mouse Embryos ◽  
Blastocyst Development ◽  
Culture Systems ◽  
Development Rates ◽  
Icr Mouse ◽  
Wide Range

In this study, in vitro preimplantation embryo culture media especially for outbred stock mice (Institute of Cancer Research (ICR)) were optimized with different concentrations of ethylenediaminetetraacetic acid (EDTA). A plot with embryo development rates against EDTA concentrations ranging from 0 to 500 µM showed a unique pattern with two characteristic peaks. Two hundred micromolar was adopted as an optimal concentration of EDTA. The optimized media were also evaluated with two culture systems: conventional large volume culture system (1 ml) and micro-droplet culture system. In the conventional large volume culture system, the blastocyst development rates were compared among three different media (F-10, KSOM and KSOM with the optimized 200 µM EDTA). The rates were 0.4%, 16.7% and 57.6%, respectively. The development rates for the micro-droplet (10 µl) culture system were 73.9%. In conclusion, 200 µM EDTA concentration in 10 µl droplets in the KSOM medium was found as the most suitable culture conditions for ICR mouse embryos, as the blastocyst development rate was higher in the micro-droplet culture system than in the traditional conventional large volume culture system.

Review of vadose zone soil solution sampling techniques

2009 ◽  
Vol 17 (NA) ◽  
pp. 215-234 ◽  
Author(s):  
Ali Fares ◽  
Sanjit K. Deb ◽  
Samira Fares
Keyword(s):  
Soil Solution ◽  
Vadose Zone ◽  
Nutrient Management ◽  
Health Impact ◽  
Soil Conditions ◽  
Sampling Techniques ◽  
In Situ Techniques ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Recent Developments

Understanding the composition and fluxes of vadose zone soil water is extremely important to many environmental studies, and hence the monitoring of soil solution is of basic interest for different scientific and practical fields, including pedologic studies, water-use management, fate and transport of environmentally consequential pollutants, monitoring of disposal from mining and industries, nutrient management of agricultural and forest ecosystems, ecology, and environmental protection. Soil solution sampling techniques for effectively monitoring the quality and quantity of vadose zone soil pore water have been used to assess the persistence and transport of potential groundwater pollutants, assess the ecological and human health impact of such pollutants, and develope appropriate remediation strategies. However, there is still no consensus as to best techniques for soil solution collection at most field or laboratory soil conditions. The purpose of this review is to evaluate different laboratory and in-situ techniques of vadose zone soil solution sampling. This comprehensive review presents and discusses advantages and disadvantages of these techniques, problems and limitations of some of these techniques, proper installation, operation and pretreatment of samplers, interaction of pollutants with sampler materials, and proper selection of samplers under a wide range of potential pollutants measurements to provide a background and guidelines for the evaluation of recent developments.

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