Configuring a fuel cell based residential combined heat and power system

Science.gov (United States)

Ahmed, Shabbir; Papadias, Dionissios D.; Ahluwalia, Rajesh K.

2013-11-01

The design and performance of a fuel cell based residential combined heat and power (CHP) system operating on natural gas has been analyzed. The natural gas is first converted to a hydrogen-rich reformate in a steam reformer based fuel processor, and the hydrogen is then electrochemically oxidized in a low temperature polymer electrolyte fuel cell to generate electric power. The heat generated in the fuel cell and the available heat in the exhaust gas is recovered to meet residential needs for hot water and space heating. Two fuel processor configurations have been studied. One of the configurations was explored to quantify the effects of design and operating parameters, which include pressure, temperature, and steam-to-carbon ratio in the fuel processor, and fuel utilization in the fuel cell. The second configuration applied the lessons from the study of the first configuration to increase the CHP efficiency. Results from the two configurations allow a quantitative comparison of the design alternatives. The analyses showed that these systems can operate at electrical efficiencies of ∼46% and combined heat and power efficiencies of ∼90%.

Computer based system for measuring the minority carrier lifetime in the solar cells

International Nuclear Information System (INIS)

Morales A, A.; Casados C, G.

1994-01-01

We show the development of a computer based system for measuring the minority carrier lifetime in the base of silicon solar cells. The system allows using two different techniques for such kind of measurements:the open circuit voltage decay (OCVD) and the surface voltage decay SVD. The equipment is based on internal cards for IBM-Pc or compatible computers that work as an oscilloscope and as a function generator, in addition to a synchronization and signal conditioning circuit. The system is fully controlled by a 'c' language program that optimizes the used of the instrument built in this way, and makes the analysis of the measurement data by curve fitting techniques. We show typical results obtained with silicon solar cells made in our laboratories. (Author)

Recent advances and challenges of fuel cell based power system architectures and control – A review

DEFF Research Database (Denmark)

Das, Vipin; Sanjeevikumar, Padmanaban; Venkitusamy, Karthikeyan

2017-01-01

by bit with expansion in current because of losses associated with fuel cell. It is difficult in handling large rated fuel cell based power system without regulating mechanism. The issue connected with fuel based structural planning and the arrangements are widely investigated for all sorts......Renewable energy generation is rapidly growing in the power sector industry and widely used for two categories: grid connected and standalone system. This paper gives the insights about fuel cell operation and application of various power electronics systems. The fuel cell voltage decreases bit...

Photoelectrochemical cells based on photosynthetic systems: a review

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Roman A. Voloshin

2015-06-01

Full Text Available Photosynthesis is a process which converts light energy into energy contained in the chemical bonds of organic compounds by photosynthetic pigments such as chlorophyll (Chl a, b, c, d, f or bacteriochlorophyll. It occurs in phototrophic organisms, which include higher plants and many types of photosynthetic bacteria, including cyanobacteria. In the case of the oxygenic photosynthesis, water is a donor of both electrons and protons, and solar radiation serves as inexhaustible source of energy. Efficiency of energy conversion in the primary processes of photosynthesis is close to 100%. Therefore, for many years photosynthesis has attracted the attention of researchers and designers looking for alternative energy systems as one of the most efficient and eco-friendly pathways of energy conversion. The latest advances in the design of optimal solar cells include the creation of converters based on thylakoid membranes, photosystems, and whole cells of cyanobacteria immobilized on nanostructured electrode (gold nanoparticles, carbon nanotubes, nanoparticles of ZnO and TiO2. The mode of solar energy conversion in photosynthesis has a great potential as a source of renewable energy while it is sustainable and environmentally safety as well. Application of pigments such as Chl f and Chl d (unlike Chl a and Chl b, by absorbing the far red and near infrared region of the spectrum (in the range 700-750 nm, will allow to increase the efficiency of such light transforming systems. This review article presents the last achievements in the field of energy photoconverters based on photosynthetic systems.

Creation of a Cell-Based Digital Cadastral Mapping System (Digital ...

African Journals Online (AJOL)

Digital cadastre enhances land transaction activities to be conducted in a business manner. Similarly, land subdivision or boundary redefinition, land registration and land marketing are achieved with better accuracy. This paper discusses the need to introduce a national Cell-Based Digital Cadastral Mapping System model ...

Novel electrical energy storage system based on reversible solid oxide cells: System design and operating conditions

Science.gov (United States)

Wendel, C. H.; Kazempoor, P.; Braun, R. J.

2015-02-01

Electrical energy storage (EES) is an important component of the future electric grid. Given that no other widely available technology meets all the EES requirements, reversible (or regenerative) solid oxide cells (ReSOCs) working in both fuel cell (power producing) and electrolysis (fuel producing) modes are envisioned as a technology capable of providing highly efficient and cost-effective EES. However, there are still many challenges and questions from cell materials development to system level operation of ReSOCs that should be addressed before widespread application. This paper presents a novel system based on ReSOCs that employ a thermal management strategy of promoting exothermic methanation within the ReSOC cell-stack to provide thermal energy for the endothermic steam/CO2 electrolysis reactions during charging mode (fuel producing). This approach also serves to enhance the energy density of the stored gases. Modeling and parametric analysis of an energy storage concept is performed using a physically based ReSOC stack model coupled with thermodynamic system component models. Results indicate that roundtrip efficiencies greater than 70% can be achieved at intermediate stack temperature (680 °C) and elevated stack pressure (20 bar). The optimal operating condition arises from a tradeoff between stack efficiency and auxiliary power requirements from balance of plant hardware.

Cell Monitoring and Manipulation Systems (CMMSs based on Glass Cell-Culture Chips (GC3s

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Sebastian M. Buehler

2016-06-01

Full Text Available We developed different types of glass cell-culture chips (GC3s for culturing cells for microscopic observation in open media-containing troughs or in microfluidic structures. Platinum sensor and manipulation structures were used to monitor physiological parameters and to allocate and permeabilize cells. Electro-thermal micro pumps distributed chemical compounds in the microfluidic systems. The integrated temperature sensors showed a linear, Pt1000-like behavior. Cell adhesion and proliferation were monitored using interdigitated electrode structures (IDESs. The cell-doubling times of primary murine embryonic neuronal cells (PNCs were determined based on the IDES capacitance-peak shifts. The electrical activity of PNC networks was detected using multi-electrode arrays (MEAs. During seeding, the cells were dielectrophoretically allocated to individual MEAs to improve network structures. MEA pads with diameters of 15, 20, 25, and 35 µm were tested. After 3 weeks, the magnitudes of the determined action potentials were highest for pads of 25 µm in diameter and did not differ when the inter-pad distances were 100 or 170 µm. Using 25-µm diameter circular oxygen electrodes, the signal currents in the cell-culture media were found to range from approximately −0.08 nA (0% O2 to −2.35 nA (21% O2. It was observed that 60-nm thick silicon nitride-sensor layers were stable potentiometric pH sensors under cell-culture conditions for periods of days. Their sensitivity between pH 5 and 9 was as high as 45 mV per pH step. We concluded that sensorized GC3s are potential animal replacement systems for purposes such as toxicity pre-screening. For example, the effect of mefloquine, a medication used to treat malaria, on the electrical activity of neuronal cells was determined in this study using a GC3 system.

Single-cell-based system to monitor carrier driven cellular auxin homeostasis

Science.gov (United States)

2013-01-01

Background Abundance and distribution of the plant hormone auxin play important roles in plant development. Besides other metabolic processes, various auxin carriers control the cellular level of active auxin and, hence, are major regulators of cellular auxin homeostasis. Despite the developmental importance of auxin transporters, a simple medium-to-high throughput approach to assess carrier activities is still missing. Here we show that carrier driven depletion of cellular auxin correlates with reduced nuclear auxin signaling in tobacco Bright Yellow-2 (BY-2) cell cultures. Results We developed an easy to use transient single-cell-based system to detect carrier activity. We use the relative changes in signaling output of the auxin responsive promoter element DR5 to indirectly visualize auxin carrier activity. The feasibility of the transient approach was demonstrated by pharmacological and genetic interference with auxin signaling and transport. As a proof of concept, we provide visual evidence that the prominent auxin transport proteins PIN-FORMED (PIN)2 and PIN5 regulate cellular auxin homeostasis at the plasma membrane and endoplasmic reticulum (ER), respectively. Our data suggest that PIN2 and PIN5 have different sensitivities to the auxin transport inhibitor 1-naphthylphthalamic acid (NPA). Also the putative PIN-LIKES (PILS) auxin carrier activity at the ER is insensitive to NPA in our system, indicating that NPA blocks intercellular, but not intracellular auxin transport. Conclusions This single-cell-based system is a useful tool by which the activity of putative auxin carriers, such as PINs, PILS and WALLS ARE THIN1 (WAT1), can be indirectly visualized in a medium-to-high throughput manner. Moreover, our single cell system might be useful to investigate also other hormonal signaling pathways, such as cytokinin. PMID:23379388

White blood cells identification system based on convolutional deep neural learning networks.

Science.gov (United States)

Shahin, A I; Guo, Yanhui; Amin, K M; Sharawi, Amr A

2017-11-16

White blood cells (WBCs) differential counting yields valued information about human health and disease. The current developed automated cell morphology equipments perform differential count which is based on blood smear image analysis. Previous identification systems for WBCs consist of successive dependent stages; pre-processing, segmentation, feature extraction, feature selection, and classification. There is a real need to employ deep learning methodologies so that the performance of previous WBCs identification systems can be increased. Classifying small limited datasets through deep learning systems is a major challenge and should be investigated. In this paper, we propose a novel identification system for WBCs based on deep convolutional neural networks. Two methodologies based on transfer learning are followed: transfer learning based on deep activation features and fine-tuning of existed deep networks. Deep acrivation featues are extracted from several pre-trained networks and employed in a traditional identification system. Moreover, a novel end-to-end convolutional deep architecture called "WBCsNet" is proposed and built from scratch. Finally, a limited balanced WBCs dataset classification is performed through the WBCsNet as a pre-trained network. During our experiments, three different public WBCs datasets (2551 images) have been used which contain 5 healthy WBCs types. The overall system accuracy achieved by the proposed WBCsNet is (96.1%) which is more than different transfer learning approaches or even the previous traditional identification system. We also present features visualization for the WBCsNet activation which reflects higher response than the pre-trained activated one. a novel WBCs identification system based on deep learning theory is proposed and a high performance WBCsNet can be employed as a pre-trained network. Copyright © 2017. Published by Elsevier B.V.

Unit cell-based computer-aided manufacturing system for tissue engineering

International Nuclear Information System (INIS)

Kang, Hyun-Wook; Park, Jeong Hun; Kang, Tae-Yun; Seol, Young-Joon; Cho, Dong-Woo

2012-01-01

Scaffolds play an important role in the regeneration of artificial tissues or organs. A scaffold is a porous structure with a micro-scale inner architecture in the range of several to several hundreds of micrometers. Therefore, computer-aided construction of scaffolds should provide sophisticated functionality for porous structure design and a tool path generation strategy that can achieve micro-scale architecture. In this study, a new unit cell-based computer-aided manufacturing (CAM) system was developed for the automated design and fabrication of a porous structure with micro-scale inner architecture that can be applied to composite tissue regeneration. The CAM system was developed by first defining a data structure for the computing process of a unit cell representing a single pore structure. Next, an algorithm and software were developed and applied to construct porous structures with a single or multiple pore design using solid freeform fabrication technology and a 3D tooth/spine computer-aided design model. We showed that this system is quite feasible for the design and fabrication of a scaffold for tissue engineering. (paper)

Unit cell-based computer-aided manufacturing system for tissue engineering.

Science.gov (United States)

Kang, Hyun-Wook; Park, Jeong Hun; Kang, Tae-Yun; Seol, Young-Joon; Cho, Dong-Woo

2012-03-01

Scaffolds play an important role in the regeneration of artificial tissues or organs. A scaffold is a porous structure with a micro-scale inner architecture in the range of several to several hundreds of micrometers. Therefore, computer-aided construction of scaffolds should provide sophisticated functionality for porous structure design and a tool path generation strategy that can achieve micro-scale architecture. In this study, a new unit cell-based computer-aided manufacturing (CAM) system was developed for the automated design and fabrication of a porous structure with micro-scale inner architecture that can be applied to composite tissue regeneration. The CAM system was developed by first defining a data structure for the computing process of a unit cell representing a single pore structure. Next, an algorithm and software were developed and applied to construct porous structures with a single or multiple pore design using solid freeform fabrication technology and a 3D tooth/spine computer-aided design model. We showed that this system is quite feasible for the design and fabrication of a scaffold for tissue engineering.

An All-Recombinant Protein-Based Culture System Specifically Identifies Hematopoietic Stem Cell Maintenance Factors

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Aki Ieyasu

2017-03-01

Full Text Available Hematopoietic stem cells (HSCs are considered one of the most promising therapeutic targets for the treatment of various blood disorders. However, due to difficulties in establishing stable maintenance and expansion of HSCs in vitro, their insufficient supply is a major constraint to transplantation studies. To solve these problems we have developed a fully defined, all-recombinant protein-based culture system. Through this system, we have identified hemopexin (HPX and interleukin-1α as responsible for HSC maintenance in vitro. Subsequent molecular analysis revealed that HPX reduces intracellular reactive oxygen species levels within cultured HSCs. Furthermore, bone marrow immunostaining and 3D immunohistochemistry revealed that HPX is expressed in non-myelinating Schwann cells, known HSC niche constituents. These results highlight the utility of this fully defined all-recombinant protein-based culture system for reproducible in vitro HSC culture and its potential to contribute to the identification of factors responsible for in vitro maintenance, expansion, and differentiation of stem cell populations.

Hydrogen storage systems based on magnesium hydride: from laboratory tests to fuel cell integration

Science.gov (United States)

de Rango, P.; Marty, P.; Fruchart, D.

2016-02-01

The paper reviews the state of the art of hydrogen storage systems based on magnesium hydride, emphasizing the role of thermal management, whose effectiveness depends on the effective thermal conductivity of the hydride, but also depends of other limiting factors such as wall contact resistance and convective exchanges with the heat transfer fluid. For daily cycles, the use of phase change material to store the heat of reaction appears to be the most effective solution. The integration with fuel cells (1 kWe proton exchange membrane fuel cell and solid oxide fuel cell) highlights the dynamic behaviour of these systems, which is related to the thermodynamic properties of MgH2. This allows for "self-adaptive" systems that do not require control of the hydrogen flow rate at the inlet of the fuel cell.

Fuel cell-based cogeneration system covering data centers’ energy needs

International Nuclear Information System (INIS)

Guizzi, Giuseppe Leo; Manno, Michele

2012-01-01

The Information and Communication Technology industry has gone in the recent years through a dramatic expansion, driven by many new online (local and remote) applications and services. Such growth has obviously triggered an equally remarkable growth in energy consumption by data centers, which require huge amounts of power not only for IT devices, but also for power distribution units and for air-conditioning systems needed to cool the IT equipment. This paper is dedicated to the economic and energy performance assessment of a cogeneration system based on a natural gas membrane steam reformer producing a pure hydrogen flow for electric power generation in a polymer electrolyte membrane fuel cell. Heat is recovered from both the reforming unit and the fuel cell in order to supply the needs of an office building located near the data center. In this case, the cooling energy needs of the data center are covered by means of a vapor-compression chiller equipped with a free-cooling unit. Since the fuel cell’s output is direct current rather than alternate current, the possibility of further improving data centers’ energy efficiency adopting DC-powered data center equipment is also discussed. -- Highlights: ► Data centers' energy needs are discussed and possible savings from advanced energy management techniques are estimated. ► The thermal energy requirements of an office building close to the data center are added to the energy scenario. ► Significant energy and cost savings can be obtained by means of free-cooling, high-voltage direct current, and a cogeneration facility. ► The cogeneration system is based on a natural gas membrane reformer and a PEM fuel cell. ► Energy flows in the membrane reformer are analyzed and an optimal value of steam-to-carbon ratio is found in order to minimize the required membrane area.

Cell Phone-Based System (Chaak) for Surveillance of Immatures of Dengue Virus Mosquito Vectors

Science.gov (United States)

LOZANO–FUENTES, SAUL; WEDYAN, FADI; HERNANDEZ–GARCIA, EDGAR; SADHU, DEVADATTA; GHOSH, SUDIPTO; BIEMAN, JAMES M.; TEP-CHEL, DIANA; GARCÍA–REJÓN, JULIÁN E.; EISEN, LARS

2014-01-01

Capture of surveillance data on mobile devices and rapid transfer of such data from these devices into an electronic database or data management and decision support systems promote timely data analyses and public health response during disease outbreaks. Mobile data capture is used increasingly for malaria surveillance and holds great promise for surveillance of other neglected tropical diseases. We focused on mosquito-borne dengue, with the primary aims of: 1) developing and field-testing a cell phone-based system (called Chaak) for capture of data relating to the surveillance of the mosquito immature stages, and 2) assessing, in the dengue endemic setting of Mérida, México, the cost-effectiveness of this new technology versus paper-based data collection. Chaak includes a desktop component, where a manager selects premises to be surveyed for mosquito immatures, and a cell phone component, where the surveyor receives the assigned tasks and captures the data. Data collected on the cell phone can be transferred to a central database through different modes of transmission, including near-real time where data are transferred immediately (e.g., over the Internet) or by first storing data on the cell phone for future transmission. Spatial data are handled in a novel, semantically driven, geographic information system. Compared with a pen-and-paper-based method, use of Chaak improved the accuracy and increased the speed of data transcription into an electronic database. The cost-effectiveness of using the Chaak system will depend largely on the up-front cost of purchasing cell phones and the recurring cost of data transfer over a cellular network. PMID:23926788

A Fluorescent Cell-Based System for Imaging Zika Virus Infection in Real-Time

Directory of Open Access Journals (Sweden)

Michael J. McFadden

2018-02-01

Full Text Available Zika virus (ZIKV is a re-emerging flavivirus that is transmitted to humans through the bite of an infected mosquito or through sexual contact with an infected partner. ZIKV infection during pregnancy has been associated with numerous fetal abnormalities, including prenatal lethality and microcephaly. However, until recent outbreaks in the Americas, ZIKV has been relatively understudied, and therefore the biology and pathogenesis of ZIKV infection remain incompletely understood. Better methods to study ZIKV infection in live cells could enhance our understanding of the biology of ZIKV and the mechanisms by which ZIKV contributes to fetal abnormalities. To this end, we developed a fluorescent cell-based reporter system allowing for live imaging of ZIKV-infected cells. This system utilizes the protease activity of the ZIKV non-structural proteins 2B and 3 (NS2B-NS3 to specifically mark virus-infected cells. Here, we demonstrate the utility of this fluorescent reporter for identifying cells infected by ZIKV strains of two lineages. Further, we use this system to determine that apoptosis is induced in cells directly infected with ZIKV in a cell-autonomous manner. Ultimately, approaches that can directly track ZIKV-infected cells at the single cell-level have the potential to yield new insights into the host-pathogen interactions that regulate ZIKV infection and pathogenesis.

Portable load-cell based system for weighing UF6 cylinders

International Nuclear Information System (INIS)

Fainberg, A.; Gordon, D.; Dermendjiev, E.; Terrey, D.; Mitchell, R.

1982-01-01

A load-cell-based portable weighing system which is capable of verifying the weights of 2.2 tonne 30-inch UF 6 cylinders has been developed by the US National Bureau of Standards (NBS). This system weighs about 13 kg and has an attainable accuracy of about 1 kg. After an initial calibration at NBS, the system is ready for use in the field. Approximately 5 to 10 minutes are needed for assembly, and, if an overhead crane has access to all cylinders to be weighed, from 10 to 15 weighings may be performed in one hour. During the past year the system has been tested at several facilities around the world with satisfactory results and with favorable comments from the facility operators. Results of several tests are presented in this paper

Cell-Free Systems Based on CHO Cell Lysates: Optimization Strategies, Synthesis of "Difficult-to-Express" Proteins and Future Perspectives.

Directory of Open Access Journals (Sweden)

Lena Thoring

Full Text Available Nowadays, biotechnological processes play a pivotal role in target protein production. In this context, Chinese Hamster Ovary (CHO cells are one of the most prominent cell lines for the expression of recombinant proteins and revealed as a safe host for nearly 40 years. Nevertheless, the major bottleneck of common in vivo protein expression platforms becomes obvious when looking at the production of so called "difficult-to-express" proteins. This class of proteins comprises in particular several ion channels and multipass membrane proteins as well as cytotoxic proteins. To enhance the production of "difficult-to-express" proteins, alternative technologies were developed, mainly based on translationally active cell lysates. These so called "cell-free" protein synthesis systems enable an efficient production of different classes of proteins. Eukaryotic cell-free systems harboring endogenous microsomal structures for the synthesis of functional membrane proteins and posttranslationally modified proteins are of particular interest for future applications. Therefore, we present current developments in cell-free protein synthesis based on translationally active CHO cell extracts, underlining the high potential of this platform. We present novel results highlighting the optimization of protein yields, the synthesis of various "difficult-to-express" proteins and the cotranslational incorporation of non-standard amino acids, which was exemplarily demonstrated by residue specific labeling of the glycoprotein Erythropoietin and the multimeric membrane protein KCSA.

An energetic-exergetic analysis of a residential CHP system based on PEM fuel cell

International Nuclear Information System (INIS)

Barelli, L.; Bidini, G.; Gallorini, F.; Ottaviano, A.

2011-01-01

Highlights: → A zero-dimensional of a micro cogenerative (CHP) energy system based on a Proton Exchange Membrane fuel cell (PEMFC) has been developed. → The electrochemical model has been validated with experimental data. → The performances of this CHP system have been evaluated through a series of simulations. → An energy/exergy analysis of the simulation results has allowed to define the PEMFC optimal operating conditions. → The PEMFC optimal operating conditions detected are: 1 atm, 353.15 K and 100% RH. -- Abstract: The use of fuel cell systems for distributed residential power generation represents an interesting alternative to traditional thermoelectric plants due to their high efficiency and the potential recovering of the heat generated by the internal electrochemical reactions. In this paper the study of a micro cogenerative (CHP) energy system based on a Proton Exchange Membrane fuel cell (PEMFC) is reported. With the aim to evaluate the performance and then the feasibility of this non-conventional energy system, in consideration of thermal and electrical basic demand of a multifamily apartment blocks, a zero-dimensional PEMFC model in Aspen Plus environment has been developed. A simulations sequence has been carried out at different operating conditions of the fuel cell (varying temperature, pressure and relative humidity). Subsequently, on the basis of the obtained results, an energy/exergy analysis has been conducted to define the optimal operating conditions of the PEMFC that ensures the most efficient use of the energy and exergy inputs.

Novel Fuel Cells for Coal Based Systems

Energy Technology Data Exchange (ETDEWEB)

Thomas Tao

2011-12-31

The goal of this project was to acquire experimental data required to assess the feasibility of a Direct Coal power plant based upon an Electrochemical Looping (ECL) of Liquid Tin Anode Solid Oxide Fuel Cell (LTA-SOFC). The objective of Phase 1 was to experimentally characterize the interaction between the tin anode, coal fuel and cell component electrolyte, the fate of coal contaminants in a molten tin reactor (via chemistry) and their impact upon the YSZ electrolyte (via electrochemistry). The results of this work will provided the basis for further study in Phase 2. The objective of Phase 2 was to extend the study of coal impurities impact on fuel cell components other than electrolyte, more specifically to the anode current collector which is made of an electrically conducting ceramic jacket and broad based coal tin reduction. This work provided a basic proof-of-concept feasibility demonstration of the direct coal concept.

Performance study of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal system

International Nuclear Information System (INIS)

Li, Ming; Ji, Xu; Li, Guoliang; Wei, Shengxian; Li, YingFeng; Shi, Feng

2011-01-01

Highlights: → The performances of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal (TCPV/T) system have been studied. → The optimum concentration ratios for the single crystalline silicon cell, the Super cells and the GaAs cells were studied by experiments. → The influences between the solar cell's performance and the series resistances, the working temperature, solar irradiation intensity were explored. - Abstract: The performances of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal (TCPV/T) system have been studied via both experiment and theoretical calculation. The I-V characteristics of the solar cell arrays and the output performances of the TCPV/T system demonstrated that among the investigated four types of solar cell arrays, the triple junction GaAs cells possessed good performance characteristics and the polysilicon cells exhibited poor performance characteristics under concentrating conditions. The optimum concentration ratios for the single crystalline silicon cell, the Super cells and the GaAs cells were also studied by experiments. The optimum concentration ratios for the single crystalline silicon cells and Super cells were 4.23 and 8.46 respectively, and the triple junction GaAs cells could work well at higher concentration ratio. Besides, some theoretical calculations and experiments were performed to explore the influences of the series resistances and the working temperature. When the series resistances R s changed from 0 Ω to 1 Ω, the maximum power P m of the single crystalline silicon, the polycrystalline silicon, the Super cell and the GaAs cell arrays decreased by 67.78%, 74.93%, 77.30% and 58.07% respectively. When the cell temperature increased by 1 K, the short circuit current of the four types of solar cell arrays decreased by 0.11818 A, 0.05364 A, 0.01387 A and 0.00215 A respectively. The research results demonstrated that the output performance of the solar cell arrays with lower

A versatile coupled cell-free transcription-translation system based on tobacco BY-2 cell lysates.

Science.gov (United States)

Buntru, Matthias; Vogel, Simon; Stoff, Katrin; Spiegel, Holger; Schillberg, Stefan

2015-05-01

Cell-free protein synthesis is a powerful method for the high-throughput production of recombinant proteins, especially proteins that are difficult to express in living cells. Here we describe a coupled cell-free transcription-translation system based on tobacco BY-2 cell lysates (BYLs). Using a combination of fractional factorial designs and response surface models, we developed a cap-independent system that produces more than 250 μg/mL of functional enhanced yellow fluorescent protein (eYFP) and about 270 μg/mL of firefly luciferase using plasmid templates, and up to 180 μg/mL eYFP using linear templates (PCR products) in 18 h batch reactions. The BYL contains actively-translocating microsomal vesicles derived from the endoplasmic reticulum, promoting the formation of disulfide bonds, glycosylation and the cotranslational integration of membrane proteins. This was demonstrated by expressing a functional full-size antibody (∼ 150 μg/mL), the model enzyme glucose oxidase (GOx) (∼ 7.3 U/mL), and a transmembrane growth factor (∼ 25 μg/mL). Subsequent in vitro treatment of GOx with peptide-N-glycosidase F confirmed the presence of N-glycans. Our results show that the BYL can be used as a high-throughput expression and screening platform that is particularly suitable for complex and cytotoxic proteins. © 2014 Wiley Periodicals, Inc.

Microfluidic cell culture systems for drug research.

Science.gov (United States)

Wu, Min-Hsien; Huang, Song-Bin; Lee, Gwo-Bin

2010-04-21

In pharmaceutical research, an adequate cell-based assay scheme to efficiently screen and to validate potential drug candidates in the initial stage of drug discovery is crucial. In order to better predict the clinical response to drug compounds, a cell culture model that is faithful to in vivo behavior is required. With the recent advances in microfluidic technology, the utilization of a microfluidic-based cell culture has several advantages, making it a promising alternative to the conventional cell culture methods. This review starts with a comprehensive discussion on the general process for drug discovery and development, the role of cell culture in drug research, and the characteristics of the cell culture formats commonly used in current microfluidic-based, cell-culture practices. Due to the significant differences in several physical phenomena between microscale and macroscale devices, microfluidic technology provides unique functionality, which is not previously possible by using traditional techniques. In a subsequent section, the niches for using microfluidic-based cell culture systems for drug research are discussed. Moreover, some critical issues such as cell immobilization, medium pumping or gradient generation in microfluidic-based, cell-culture systems are also reviewed. Finally, some practical applications of microfluidic-based, cell-culture systems in drug research particularly those pertaining to drug toxicity testing and those with a high-throughput capability are highlighted.

Advanced control approach for hybrid systems based on solid oxide fuel cells

International Nuclear Information System (INIS)

Ferrari, Mario L.

2015-01-01

Highlights: • Advanced new control system for SOFC based hybrid plants. • Proportional–Integral approach with feed-forward technology. • Good control of fuel cell temperature. • All critical properties maintained inside safe conditions. - Abstract: This paper shows a new advanced control approach for operations in hybrid systems equipped with solid oxide fuel cell technology. This new tool, which combines feed-forward and standard proportional–integral techniques, controls the system during load changes avoiding failures and stress conditions detrimental to component life. This approach was selected to combine simplicity and good control performance. Moreover, the new approach presented in this paper eliminates the need for mass flow rate meters and other expensive probes, as usually required for a commercial plant. Compared to previous works, better performance is achieved in controlling fuel cell temperature (maximum gradient significantly lower than 3 K/min), reducing the pressure gap between cathode and anode sides (at least a 30% decrease during transient operations), and generating a higher safe margin (at least a 10% increase) for the Steam-to-Carbon Ratio. This new control system was developed and optimized using a hybrid system transient model implemented, validated and tested within previous works. The plant, comprising the coupling of a tubular solid oxide fuel cell stack with a microturbine, is equipped with a bypass valve able to connect the compressor outlet with the turbine inlet duct for rotational speed control. Following model development and tuning activities, several operative conditions were considered to show the new control system increased performance compared to previous tools (the same hybrid system model was used with the new control approach). Special attention was devoted to electrical load steps and ramps considering significant changes in ambient conditions

A Fluid Membrane-Based Soluble Ligand Display System for Live CellAssays

Energy Technology Data Exchange (ETDEWEB)

Nam, Jwa-Min; Nair, Pradeep N.; Neve, Richard M.; Gray, Joe W.; Groves, Jay T.

2005-10-14

Cell communication modulates numerous biological processes including proliferation, apoptosis, motility, invasion and differentiation. Correspondingly, there has been significant interest in the development of surface display strategies for the presentation of signaling molecules to living cells. This effort has primarily focused on naturally surface-bound ligands, such as extracellular matrix components and cell membranes. Soluble ligands (e.g. growth factors and cytokines) play an important role in intercellular communications, and their display in a surface-bound format would be of great utility in the design of array-based live cell assays. Recently, several cell microarray systems that display cDNA, RNAi, or small molecules in a surface array format were proven to be useful in accelerating high-throughput functional genetic studies and screening therapeutic agents. These surface display methods provide a flexible platform for the systematic, combinatorial investigation of genes and small molecules affecting cellular processes and phenotypes of interest. In an analogous sense, it would be an important advance if one could display soluble signaling ligands in a surface assay format that allows for systematic, patterned presentation of soluble ligands to live cells. Such a technique would make it possible to examine cellular phenotypes of interest in a parallel format with soluble signaling ligands as one of the display parameters. Herein we report a ligand-modified fluid supported lipid bilayer (SLB) assay system that can be used to functionally display soluble ligands to cells in situ (Figure 1A). By displaying soluble ligands on a SLB surface, both solution behavior (the ability to become locally enriched by reaction-diffusion processes) and solid behavior (the ability to control the spatial location of the ligands in an open system) could be combined. The method reported herein benefits from the naturally fluid state of the supported membrane, which allows

Microfluidic-Based Synthesis of Hydrogel Particles for Cell Microencapsulation and Cell-Based Drug Delivery

Directory of Open Access Journals (Sweden)

Jiandi Wan

2012-04-01

Full Text Available Encapsulation of cells in hydrogel particles has been demonstrated as an effective approach to deliver therapeutic agents. The properties of hydrogel particles, such as the chemical composition, size, porosity, and number of cells per particle, affect cellular functions and consequently play important roles for the cell-based drug delivery. Microfluidics has shown unparalleled advantages for the synthesis of polymer particles and been utilized to produce hydrogel particles with a well-defined size, shape and morphology. Most importantly, during the encapsulation process, microfluidics can control the number of cells per particle and the overall encapsulation efficiency. Therefore, microfluidics is becoming the powerful approach for cell microencapsulation and construction of cell-based drug delivery systems. In this article, I summarize and discuss microfluidic approaches that have been developed recently for the synthesis of hydrogel particles and encapsulation of cells. I will start by classifying different types of hydrogel material, including natural biopolymers and synthetic polymers that are used for cell encapsulation, and then focus on the current status and challenges of microfluidic-based approaches. Finally, applications of cell-containing hydrogel particles for cell-based drug delivery, particularly for cancer therapy, are discussed.

Fuel Cell Power Model Version 2: Startup Guide, System Designs, and Case Studies. Modeling Electricity, Heat, and Hydrogen Generation from Fuel Cell-Based Distributed Energy Systems

Energy Technology Data Exchange (ETDEWEB)

Steward, D.; Penev, M.; Saur, G.; Becker, W.; Zuboy, J.

2013-06-01

This guide helps users get started with the U.S. Department of Energy/National Renewable Energy Laboratory Fuel Cell Power (FCPower) Model Version 2, which is a Microsoft Excel workbook that analyzes the technical and economic aspects of high-temperature fuel cell-based distributed energy systems with the aim of providing consistent, transparent, comparable results. This type of energy system would provide onsite-generated heat and electricity to large end users such as hospitals and office complexes. The hydrogen produced could be used for fueling vehicles or stored for later conversion to electricity.

ISABELLE half-cell control system

International Nuclear Information System (INIS)

Buxton, W.; Frankel, R.; Humphrey, J.W.

1977-01-01

The primary function of the ISABELLE half-cell control system is to monitor and control the magnet power supplies of the half-cell. In addition, the control system must be flexible enough that it can be expanded to become involved in additional areas such as vacuum and magnetic measurements. A control system based upon AGS control standards, but modified into a development tool for research and electrical engineering support was constructed. Special attention was given to the inherent differences between controlling an ISABELLE and a conventional fast cycling accelerator. The use of FORTRAN and BASIC networks, and microprocessors is reviewed insofar as they pertain to this system. Some general opinions on model control systems, based upon experience, are presented

Robust Allocation of Reserve Policies for a Multiple-Cell Based Power System

DEFF Research Database (Denmark)

Hu, Junjie; Lan, Tian; Heussen, Kai

2018-01-01

modifications. The LDR method can effectively adapt the participation factors of reserve providers to respond to system imbalance signals. The policies considered the covariance of historic system imbalance signals to reduce the overall reserve cost. When applying this method to the cell-based power system...... for a certain horizon, the influence of different time resolutions on policy-making is also investigated, which presents guidance for its practical application. The main results illustrate that: (a) the LDR-based method shows better performance, by producing smaller reserve costs compared to the costs given...... by a reference method; and (b) the cost index decreases with increased time intervals, however, longer intervals might result in insufficient reserves, due to low time resolution. On the other hand, shorter time intervals require heavy computational time. Thus, it is important to choose a proper time interval...

Cell fiber-based three-dimensional culture system for highly efficient expansion of human induced pluripotent stem cells.

Science.gov (United States)

Ikeda, Kazuhiro; Nagata, Shogo; Okitsu, Teru; Takeuchi, Shoji

2017-06-06

Human pluripotent stem cells are a potentially powerful cellular resource for application in regenerative medicine. Because such applications require large numbers of human pluripotent stem cell-derived cells, a scalable culture system of human pluripotent stem cell needs to be developed. Several suspension culture systems for human pluripotent stem cell expansion exist; however, it is difficult to control the thickness of cell aggregations in these systems, leading to increased cell death likely caused by limited diffusion of gases and nutrients into the aggregations. Here, we describe a scalable culture system using the cell fiber technology for the expansion of human induced pluripotent stem (iPS) cells. The cells were encapsulated and cultured within the core region of core-shell hydrogel microfibers, resulting in the formation of rod-shaped or fiber-shaped cell aggregations with sustained thickness and high viability. By encapsulating the cells with type I collagen, we demonstrated a long-term culture of the cells by serial passaging at a high expansion rate (14-fold in four days) while retaining its pluripotency. Therefore, our culture system could be used for large-scale expansion of human pluripotent stem cells for use in regenerative medicine.

Development of a novel cell-based assay system EPISSAY for screening epigenetic drugs and liposome formulated decitabine

International Nuclear Information System (INIS)

Lim, Sue Ping; Callen, David F; Kumar, Raman; Akkamsetty, Yamini; Wang, Wen; Ho, Kristen; Neilsen, Paul M; Walther, Diego J; Suetani, Rachel J; Prestidge, Clive

2013-01-01

Despite the potential of improving the delivery of epigenetic drugs, the subsequent assessment of changes in their epigenetic activity is largely dependent on the availability of a suitable and rapid screening bioassay. Here, we describe a cell-based assay system for screening gene reactivation. A cell-based assay system (EPISSAY) was designed based on a silenced triple-mutated bacterial nitroreductase TMnfsB fused with Red-Fluorescent Protein (RFP) expressed in the non-malignant human breast cell line MCF10A. EPISSAY was validated using the target gene TXNIP, which has previously been shown to respond to epigenetic drugs. The potency of a epigenetic drug model, decitabine, formulated with PEGylated liposomes was also validated using this assay system. Following treatment with DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors such as decitabine and vorinostat, increases in RFP expression were observed, indicating expression of RFP-TMnfsB. The EPISSAY system was then used to test the potency of decitabine, before and after PEGylated liposomal encapsulation. We observed a 50% higher potency of decitabine when encapsulated in PEGylated liposomes, which is likely to be due to its protection from rapid degradation. The EPISSAY bioassay system provides a novel and rapid system to compare the efficiencies of existing and newly formulated drugs that reactivate gene expression

Microemulsion-based synergistic dual-drug codelivery system for enhanced apoptosis of tumor cells.

Science.gov (United States)

Qu, Ding; Ma, Yihua; Sun, Wenjie; Chen, Yan; Zhou, Jing; Liu, Congyan; Huang, Mengmeng

2015-01-01

A microemulsion-based synergistic dual-drug codelivery system was developed for enhanced cell apoptosis by transporting coix seed oil and etoposide into A549 (human lung carcinoma) cells simultaneously. Results obtained by dynamic light scattering showed that an etoposide (VP16)-loaded coix seed oil microemulsion (EC-ME) delivery system had a small size around 35 nm, a narrow polydispersity index, and a slightly negative surface charge. The encapsulating efficiency and total drug loading rate were 97.01% and 45.48%, respectively, by high-performance liquid chromatography. The release profiles at various pH values showed an obvious pH-responsive difference, with the accumulated amount of VP16 released at pH 4.5 (and pH 5.5) being 2.7-fold higher relative to that at pH 7.4. Morphologic alteration (particle swelling) associated with a mildly acidic pH environment was found on transmission electron microscopy. In the cell study, the EC-ME system showed a significantly greater antiproliferative effect toward A549 cells in comparison with free VP16 and the mixture of VP16 and coix seed oil. The half-maximal inhibitory concentration of the EC-ME system was 3.9-fold and 10.4-fold lower relative to that of free VP16 and a mixture of VP16 and coix seed oil, respectively. Moreover, fluorescein isothiocyanate and VP16 (the green fluorescent probe and entrapped drug, respectively) were efficiently internalized into the cells by means of coix seed oil microemulsion through intuitive observation and quantitative measurement. Importantly, an EC-ME system containing 20 μg/mL of VP16 showed a 3.3-fold and 3.5-fold improvement in induction of cell apoptosis compared with the VP-16-loaded microemulsion and free VP16, respectively. The EC-ME combination strategy holds promise as an efficient drug delivery system for induction of apoptosis and treatment of lung cancer.

A tri-generation system based on polymer electrolyte fuel cell and desiccant wheel – Part A: Fuel cell system modelling and partial load analysis

International Nuclear Information System (INIS)

Najafi, Behzad; De Antonellis, Stefano; Intini, Manuel; Zago, Matteo; Rinaldi, Fabio; Casalegno, Andrea

2015-01-01

Highlights: • A mathematical model for a PEMFC based cogeneration system is developed. • Developed model is validated using the available experimental data. • Performance of the plant at full load conditions is investigated. • Performance indices while applying two different modifications are determined. • System’s performance with and without modifications at partial loads is investigated. - Abstract: Polymer Electrolyte Membrane Fuel Cell (PEMFC) based systems have recently received increasing attention as a viable alternative for meeting the residential electrical and thermal demands. However, as the intermittent demand profiles of a building can only be addressed by a tri-generative unit which can operate at partial loads, the variation of performance of the system at partial loads might affect its corresponding potential benefits significantly. Nonetheless, no previous study has been carried out on assessing the performance of this type of tri-generative systems in such conditions. The present paper is the first of a two part study dedicated to the investigation of the performance of a tri-generative system in which a PEMFC based system is coupled with a desiccant wheel unit. This study is focused on evaluating the performance of the PEMFC subsystem while operating at partial loads. Accordingly, a detailed mathematical model of the fuel cell subsystem is first developed and validated using the experimental data obtained from the plant’s and the fuel cell stack’s manufacturer. Next, in order to increase the performance of the plant, two modifications have been proposed and the resulting performance at partial load have been determined. The obtained results demonstrate that applying both modifications results in increasing the electrical efficiency of the plant by 5.5%. It is also shown that, while operating at partial loads, the electrical efficiency of the plant does not significantly change; the fact which corresponds to the trade-off between

A system for the rapid detection of bacterial contamination in cell-based therapeutica

Science.gov (United States)

Bolwien, Carsten; Erhardt, Christian; Sulz, Gerd; Thielecke, Hagen; Johann, Robert; Pudlas, Marieke; Mertsching, Heike; Koch, Steffen

2010-02-01

Monitoring the sterility of cell or tissue cultures is of major concern, particularly in the fields of regenerative medicine and tissue engineering when implanting cells into the human body. Our sterility-control system is based on a Raman micro-spectrometer and is able to perform fast sterility testing on microliters of liquid samples. In conventional sterility control, samples are incubated for weeks to proliferate the contaminants to concentrations above the detection limit of conventional analysis. By contrast, our system filters particles from the liquid sample. The filter chip fabricated in microsystem technology comprises a silicon nitride membrane with millions of sub-micrometer holes to retain particles of critical sizes and is embedded in a microfluidic cell specially suited for concomitant microscopic observation. After filtration, identification is carried out on the single particle level: image processing detects possible contaminants and prepares them for Raman spectroscopic analysis. A custom-built Raman-spectrometer-attachment coupled to the commercial microscope uses 532nm or 785nm Raman excitation and records spectra up to 3400cm-1. In the final step, the recorded spectrum of a single particle is compared to an extensive library of GMP-relevant organisms, and classification is carried out based on a support vector machine.

Load-cell-based weighing system for weighing 9.1- and 12.7-tonne UF6 cylinders

International Nuclear Information System (INIS)

McAuley, W.A.; Kane, W.R.

1986-01-01

For the independent verification of UF 6 cylinder masses by the International Atomic Energy Agency (IAEA) at uranium enrichment facilities, an 18-tonne capacity Load-Cell-Based Weighing System (LCBWS) has been developed. The system was developed at Brookhaven National Laboratory and the Oak Ridge Gaseous Diffusion Plant and calibrated at the US National Bureau of Standards. The principal components of the LCBWS are two load cells, with readout and ancillary equipment, and a lifting fixture that couples the load cells to a cylinder. Initial experience with the system demonstrates that it has the advantages of transportability, ease of application, stability, and an attainable accuracy of 2 kg or better for a full cylinder

Monte Carlo dose calculation using a cell processor based PlayStation 3 system

International Nuclear Information System (INIS)

Chow, James C L; Lam, Phil; Jaffray, David A

2012-01-01

This study investigates the performance of the EGSnrc computer code coupled with a Cell-based hardware in Monte Carlo simulation of radiation dose in radiotherapy. Performance evaluations of two processor-intensive functions namely, HOWNEAR and RANMAR G ET in the EGSnrc code were carried out basing on the 20-80 rule (Pareto principle). The execution speeds of the two functions were measured by the profiler gprof specifying the number of executions and total time spent on the functions. A testing architecture designed for Cell processor was implemented in the evaluation using a PlayStation3 (PS3) system. The evaluation results show that the algorithms examined are readily parallelizable on the Cell platform, provided that an architectural change of the EGSnrc was made. However, as the EGSnrc performance was limited by the PowerPC Processing Element in the PS3, PC coupled with graphics processing units or GPCPU may provide a more viable avenue for acceleration.

Monte Carlo dose calculation using a cell processor based PlayStation 3 system

Science.gov (United States)

Chow, James C. L.; Lam, Phil; Jaffray, David A.

2012-02-01

This study investigates the performance of the EGSnrc computer code coupled with a Cell-based hardware in Monte Carlo simulation of radiation dose in radiotherapy. Performance evaluations of two processor-intensive functions namely, HOWNEAR and RANMAR_GET in the EGSnrc code were carried out basing on the 20-80 rule (Pareto principle). The execution speeds of the two functions were measured by the profiler gprof specifying the number of executions and total time spent on the functions. A testing architecture designed for Cell processor was implemented in the evaluation using a PlayStation3 (PS3) system. The evaluation results show that the algorithms examined are readily parallelizable on the Cell platform, provided that an architectural change of the EGSnrc was made. However, as the EGSnrc performance was limited by the PowerPC Processing Element in the PS3, PC coupled with graphics processing units or GPCPU may provide a more viable avenue for acceleration.

Monte Carlo dose calculation using a cell processor based PlayStation 3 system

Energy Technology Data Exchange (ETDEWEB)

Chow, James C L; Lam, Phil; Jaffray, David A, E-mail: james.chow@rmp.uhn.on.ca [Department of Radiation Oncology, University of Toronto and Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, Ontario M5G 2M9 (Canada)

2012-02-09

This study investigates the performance of the EGSnrc computer code coupled with a Cell-based hardware in Monte Carlo simulation of radiation dose in radiotherapy. Performance evaluations of two processor-intensive functions namely, HOWNEAR and RANMAR{sub G}ET in the EGSnrc code were carried out basing on the 20-80 rule (Pareto principle). The execution speeds of the two functions were measured by the profiler gprof specifying the number of executions and total time spent on the functions. A testing architecture designed for Cell processor was implemented in the evaluation using a PlayStation3 (PS3) system. The evaluation results show that the algorithms examined are readily parallelizable on the Cell platform, provided that an architectural change of the EGSnrc was made. However, as the EGSnrc performance was limited by the PowerPC Processing Element in the PS3, PC coupled with graphics processing units or GPCPU may provide a more viable avenue for acceleration.

UPS Project for GSM base stations with a fuel cell (PEM fuel cell back-up system) - Final report; Projekt USV fuer GSM-Basisstationen mit BZ (PEM fuel cell back-up system) - Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Trachte, U.

2007-07-01

The University of applied sciences HTA Lucerne designed a prototype of an uninterruptible power supply (UPS) with Fuel Cell technology instead of lead-acid batteries and put it into operation. The delayed start-up of the Fuel Cell was bridged with ultra capacitor technology. In a first project stage the system was designed, assembled and tested in laboratory. In a second stage the installation was connected to a real base station of a telecommunication antenna and put to field tests for one year. The field test included monthly simulations of power failure with antenna load of about 2.4 kW as well as tests with external load up to 8.5 kW to establish the characteristic diagram. Hydrogen was provided by two 50 l pressure tanks. The full quantity of hydrogen secured a stand-alone operation of the Fuel Cell system for about 6 hours under antenna load. The results of the 101 grid-failure simulations demonstrate a very reliable start-up behaviour of the Fuel Cell System. Also during a real power failure due to a thunderstorm the installation provided the demanded power without any problem. The total duration of operation of the Fuel Cell during the field tests was 39 hours. No degradation could be noticed. The project takes place in collaboration with the industrial partners APC Industrial Systems, as a producer and market leader of UPS-Systems, and Swisscom Mobile AG, as a user of UPS-systems in telecommunications. Following the good results and in order to get more experience in long-term operation of the Fuel Cell system the tests will go on for two more years. (author)

Jet Fuel Based High Pressure Solid Oxide Fuel Cell System

Science.gov (United States)

Gummalla, Mallika (Inventor); Yamanis, Jean (Inventor); Olsommer, Benoit (Inventor); Dardas, Zissis (Inventor); Bayt, Robert (Inventor); Srinivasan, Hari (Inventor); Dasgupta, Arindam (Inventor); Hardin, Larry (Inventor)

2015-01-01

A power system for an aircraft includes a solid oxide fuel cell system which generates electric power for the aircraft and an exhaust stream; and a heat exchanger for transferring heat from the exhaust stream of the solid oxide fuel cell to a heat requiring system or component of the aircraft. The heat can be transferred to fuel for the primary engine of the aircraft. Further, the same fuel can be used to power both the primary engine and the SOFC. A heat exchanger is positioned to cool reformate before feeding to the fuel cell. SOFC exhaust is treated and used as inerting gas. Finally, oxidant to the SOFC can be obtained from the aircraft cabin, or exterior, or both.

Micro-electro-mechanical systems (MEMS)-based micro-scale direct methanol fuel cell development

International Nuclear Information System (INIS)

Yao, S.-C.; Tang Xudong; Hsieh, C.-C.; Alyousef, Yousef; Vladimer, Michael; Fedder, Gary K.; Amon, Cristina H.

2006-01-01

This paper describes a high-power density, silicon-based micro-scale direct methanol fuel cell (DMFC), under development at Carnegie Mellon. Major issues in the DMFC design include the water management and energy-efficient micro fluidic sub-systems. The air flow and the methanol circulation are both at a natural draft, while a passive liquid-gas separator removes CO 2 from the methanol chamber. An effective approach for maximizing the DMFC energy density, pumping the excess water back to the anode, is illustrated. The proposed DMFC contains several unique features: a silicon wafer with arrays of etched holes selectively coated with a non-wetting agent for collecting water at the cathode; a silicon membrane micro pump for pumping the collected water back to the anode; and a passive liquid-gas separator for CO 2 removal. All of these silicon-based components are fabricated using micro-electro-mechanical systems (MEMS)-based processes on the same silicon wafer, so that interconnections are eliminated, and integration efforts as well as post-fabrication costs are both minimized. The resulting fuel cell has an overall size of one cubic inch, produces a net output of 10 mW, and has an energy density three to five times higher than that of current lithium-ion batteries

Trigeneration System Based on Municipal Waste Gasification, Fuel Cell and an Absorption Chiller

DEFF Research Database (Denmark)

Katsaros, Giannis; Nguyen, Tuong-Van; Rokni, Masoud

2016-01-01

of a specific building is also investigated and the system can fully meet the electricity and cooling demands, whereas the heat needs can be satisfied only up to 55%. Moreover, assuming 20 years of operation, the payback period is 4.3 years and the net present value exceeds 5 MEUR.......The present work focuses on the design of a novel tri-generation system based on municipal solid wastes gasification, solid oxide fuel cell and an ammonia-water absorption chiller. Trigeneration systems can be implemented in buildings such as hospitals, where there is a continuous and large demand...

Quantitative Assessment of Pap Smear Cells by PC-Based Cytopathologic Image Analysis System and Support Vector Machine

Science.gov (United States)

Huang, Po-Chi; Chan, Yung-Kuan; Chan, Po-Chou; Chen, Yung-Fu; Chen, Rung-Ching; Huang, Yu-Ruei

Cytologic screening has been widely used for controlling the prevalence of cervical cancer. Errors from sampling, screening and interpretation, still concealed some unpleasant results. This study aims at designing a cellular image analysis system based on feasible and available software and hardware for a routine cytologic laboratory. Totally 1814 cellular images from the liquid-based cervical smears with Papanicolaou stain in 100x, 200x, and 400x magnification were captured by a digital camera. Cell images were reviewed by pathologic experts with peer agreement and only 503 images were selected for further study. The images were divided into 4 diagnostic categories. A PC-based cellular image analysis system (PCCIA) was developed for computing morphometric parameters. Then support vector machine (SVM) was used to classify signature patterns. The results show that the selected 13 morphometric parameters can be used to correctly differentiate the dysplastic cells from the normal cells (pgynecologic cytologic specimens.

Dynamic Control Based Photovoltaic Illuminating System

Directory of Open Access Journals (Sweden)

Zhang Chengkai

2016-01-01

Full Text Available Smart LED illumination system can use the power from whether the photovoltaic cell or the power grid automatically based on the SOC (State Of Charge of the photovoltaic cell. This paper proposes a feedback control of the photovoltaic cells and a dynamic control strategy for the Energy system. The dynamic control strategy is used to determine the switching state of the photovoltaic cell based on the illumination load in the past one hour and the battery capacity. These controls are manifested by experimental prototype that the control scheme is correct and effective.

Microfabricated Electrochemical Cell-Based Biosensors for Analysis of Living Cells In Vitro

Directory of Open Access Journals (Sweden)

Jun Wang

2012-04-01

Full Text Available Cellular biochemical parameters can be used to reveal the physiological and functional information of various cells. Due to demonstrated high accuracy and non-invasiveness, electrochemical detection methods have been used for cell-based investigation. When combined with improved biosensor design and advanced measurement systems, the on-line biochemical analysis of living cells in vitro has been applied for biological mechanism study, drug screening and even environmental monitoring. In recent decades, new types of miniaturized electrochemical biosensor are emerging with the development of microfabrication technology. This review aims to give an overview of the microfabricated electrochemical cell-based biosensors, such as microelectrode arrays (MEA, the electric cell-substrate impedance sensing (ECIS technique, and the light addressable potentiometric sensor (LAPS. The details in their working principles, measurement systems, and applications in cell monitoring are covered. Driven by the need for high throughput and multi-parameter detection proposed by biomedicine, the development trends of electrochemical cell-based biosensors are also introduced, including newly developed integrated biosensors, and the application of nanotechnology and microfluidic technology.

Cell-based therapeutic strategies for multiple sclerosis.

Science.gov (United States)

Scolding, Neil J; Pasquini, Marcelo; Reingold, Stephen C; Cohen, Jeffrey A

2017-11-01

The availability of multiple disease-modifying medications with regulatory approval to treat multiple sclerosis illustrates the substantial progress made in therapy of the disease. However, all are only partially effective in preventing inflammatory tissue damage in the central nervous system and none directly promotes repair. Cell-based therapies, including immunoablation followed by autologous haematopoietic stem cell transplantation, mesenchymal and related stem cell transplantation, pharmacologic manipulation of endogenous stem cells to enhance their reparative capabilities, and transplantation of oligodendrocyte progenitor cells, have generated substantial interest as novel therapeutic strategies for immune modulation, neuroprotection, or repair of the damaged central nervous system in multiple sclerosis. Each approach has potential advantages but also safety concerns and unresolved questions. Moreover, clinical trials of cell-based therapies present several unique methodological and ethical issues. We summarize here the status of cell-based therapies to treat multiple sclerosis and make consensus recommendations for future research and clinical trials. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain.

Cell-Based Sensor System Using L6 Cells for Broad Band Continuous Pollutant Monitoring in Aquatic Environments

Directory of Open Access Journals (Sweden)

Evamaria Stütz

2012-03-01

Full Text Available Pollution of drinking water sources represents a continuously emerging problem in global environmental protection. Novel techniques for real-time monitoring of water quality, capable of the detection of unanticipated toxic and bioactive substances, are urgently needed. In this study, the applicability of a cell-based sensor system using selected eukaryotic cell lines for the detection of aquatic pollutants is shown. Readout parameters of the cells were the acidification (metabolism, oxygen consumption (respiration and impedance (morphology of the cells. A variety of potential cytotoxic classes of substances (heavy metals, pharmaceuticals, neurotoxins, waste water was tested with monolayers of L6 cells (rat myoblasts. The cytotoxicity or cellular effects induced by inorganic ions (Ni2+ and Cu2+ can be detected with the metabolic parameters acidification and respiration down to 0.5 mg/L, whereas the detection limit for other substances like nicotine and acetaminophen are rather high, in the range of 0.1 mg/L and 100 mg/L. In a close to application model a real waste water sample shows detectable signals, indicating the existence of cytotoxic substances. The results support the paradigm change from single substance detection to the monitoring of overall toxicity.

Non-genetic engineering of cells for drug delivery and cell-based therapy.

Science.gov (United States)

Wang, Qun; Cheng, Hao; Peng, Haisheng; Zhou, Hao; Li, Peter Y; Langer, Robert

2015-08-30

Cell-based therapy is a promising modality to address many unmet medical needs. In addition to genetic engineering, material-based, biochemical, and physical science-based approaches have emerged as novel approaches to modify cells. Non-genetic engineering of cells has been applied in delivering therapeutics to tissues, homing of cells to the bone marrow or inflammatory tissues, cancer imaging, immunotherapy, and remotely controlling cellular functions. This new strategy has unique advantages in disease therapy and is complementary to existing gene-based cell engineering approaches. A better understanding of cellular systems and different engineering methods will allow us to better exploit engineered cells in biomedicine. Here, we review non-genetic cell engineering techniques and applications of engineered cells, discuss the pros and cons of different methods, and provide our perspectives on future research directions. Copyright © 2014 Elsevier B.V. All rights reserved.

A versatile system for USER cloning-based assembly of expression vectors for mammalian cell engineering.

Directory of Open Access Journals (Sweden)

Anne Mathilde Lund

Full Text Available A new versatile mammalian vector system for protein production, cell biology analyses, and cell factory engineering was developed. The vector system applies the ligation-free uracil-excision based technique--USER cloning--to rapidly construct mammalian expression vectors of multiple DNA fragments and with maximum flexibility, both for choice of vector backbone and cargo. The vector system includes a set of basic vectors and a toolbox containing a multitude of DNA building blocks including promoters, terminators, selectable marker- and reporter genes, and sequences encoding an internal ribosome entry site, cellular localization signals and epitope- and purification tags. Building blocks in the toolbox can be easily combined as they contain defined and tested Flexible Assembly Sequence Tags, FASTs. USER cloning with FASTs allows rapid swaps of gene, promoter or selection marker in existing plasmids and simple construction of vectors encoding proteins, which are fused to fluorescence-, purification-, localization-, or epitope tags. The mammalian expression vector assembly platform currently allows for the assembly of up to seven fragments in a single cloning step with correct directionality and with a cloning efficiency above 90%. The functionality of basic vectors for FAST assembly was tested and validated by transient expression of fluorescent model proteins in CHO, U-2-OS and HEK293 cell lines. In this test, we included many of the most common vector elements for heterologous gene expression in mammalian cells, in addition the system is fully extendable by other users. The vector system is designed to facilitate high-throughput genome-scale studies of mammalian cells, such as the newly sequenced CHO cell lines, through the ability to rapidly generate high-fidelity assembly of customizable gene expression vectors.

Establishing a high yielding streptomyces-based cell-free protein synthesis system.

Science.gov (United States)

Li, Jian; Wang, He; Kwon, Yong-Chan; Jewett, Michael C

2017-06-01

Cell-free protein synthesis (CFPS) has emerged as a powerful platform for applied biotechnology and synthetic biology, with a range of applications in synthesizing proteins, evolving proteins, and prototyping genetic circuits. To expand the current CFPS repertoire, we report here the development and optimization of a Streptomyces-based CFPS system for the expression of GC-rich genes. By developing a streamlined crude extract preparation protocol and optimizing reaction conditions, we were able to achieve active enhanced green fluorescent protein (EGFP) yields of greater than 50 μg/mL with batch reactions lasting up to 3 h. By adopting a semi-continuous reaction format, the EGFP yield could be increased to 282 ± 8 μg/mL and the reaction time was extended to 48 h. Notably, our extract preparation procedures were robust to multiple Streptomyces lividans and Streptomyces coelicolor strains, although expression yields varied. We show that our optimized Streptomyces lividans system provides benefits when compared to an Escherichia coli-based CFPS system for increasing percent soluble protein expression for four Streptomyces-originated high GC-content genes that are involved in biosynthesis of the nonribosomal peptides tambromycin and valinomycin. Looking forward, we believe that our Streptomyces-based CFPS system will contribute significantly towards efforts to express complex natural product gene clusters (e.g., nonribosomal peptides and polyketides), providing a new avenue for obtaining and studying natural product biosynthesis pathways. Biotechnol. Bioeng. 2017;114: 1343-1353. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Environmental tests of metallization systems for terrestrial photovoltaic cells

Science.gov (United States)

Alexander, P., Jr.

1985-01-01

Seven different solar cell metallization systems were subjected to temperature cycling tests and humidity tests. Temperature cycling excursions were -50 deg C to 150 deg C per cycle. Humidity conditions were 70 deg C at 98% relative humidity. The seven metallization systems were: Ti/Ag, Ti/Pd/Ag, Ti/Pd/Cu, Ni/Cu, Pd/Ni/Solder, Cr/Pd/Ag, and thick film Ag. All metallization systems showed a slight to moderate decrease in cell efficiencies after subjection to 1000 temperature cycles. Six of the seven metallization systems also evidenced slight increases in cell efficiencies after moderate numbers of cycles, generally less than 100 cycles. The copper based systems showed the largest decrease in cell efficiencies after temperature cycling. All metallization systems showed moderate to large decreases in cell efficiencies after 123 days of humidity exposure. The copper based systems again showed the largest decrease in cell efficiencies after humidity exposure. Graphs of the environmental exposures versus cell efficiencies are presented for each metallization system, as well as environmental exposures versus fill factors or series resistance.

Min-max control of fuel-cell-car-based smart energy systems

OpenAIRE

Alavi, F.; van de Wouw, N.; De Schutter, B.H.K.; Rantzer, Anders; Bagterp Jørgensen, John; Stoustrup, Jakob

2016-01-01

Recently, the idea of using fuel cell vehicles as the future way of producing electricity has emerged. A fuel cell car has all the necessary devices on board to convert the chemical energy of hydrogen into electricity. This paper considers a scenario where a parking lot for fuel cell cars acts as a virtual power plant. In order to describe the system behavior from the energy point of view, a hybrid (mixed logical dynamical) model is constructed. With this model, a control system is designed t...

Analysis of DC/DC Converter Efficiency for Energy Storage System Based on Bidirectional Fuel Cells

DEFF Research Database (Denmark)

Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

2013-01-01

interface to the grid. In power electronics, the converter efficiency is characterized at fixed operating voltage for various output power. This type of characterization is not suitable for fuel cells, since as the power from the fuel cell increases, the cell voltage decreases. This paper analyses how......Renewable energy sources are fluctuating depending on the availability of the energy source. For this reason, energy storage is becoming more important and bidirectional fuel cells represent an attractive technology. Fuel cells require highcurrent low-voltage dc-dc or dc-ac converters as power...... the fuel cell I-V characteristics influences the power electronics converter efficiency and their consequence on the overall system. A loaddependent efficiency curve is presented based on experimental results from a 6 kW dc-dc converter prototype including the most suitable control strategy which maximizes...

System-level modeling and simulation of the cell culture microfluidic biochip ProCell

DEFF Research Database (Denmark)

Minhass, Wajid Hassan; Pop, Paul; Madsen, Jan

2010-01-01

Microfluidic biochips offer a promising alternative to a conventional biochemical laboratory. There are two technologies for the microfluidic biochips: droplet-based and flow-based. In this paper we are interested in flow-based microfluidic biochips, where the liquid flows continuously through pre......-defined micro-channels using valves and pumps. We present an approach to the system-level modeling and simulation of a cell culture microfluidic biochip called ProCell, Programmable Cell Culture Chip. ProCell contains a cell culture chamber, which is envisioned to run 256 simultaneous experiments (viewed...

Speech recognition systems on the Cell Broadband Engine

Energy Technology Data Exchange (ETDEWEB)

Liu, Y; Jones, H; Vaidya, S; Perrone, M; Tydlitat, B; Nanda, A

2007-04-20

In this paper we describe our design, implementation, and first results of a prototype connected-phoneme-based speech recognition system on the Cell Broadband Engine{trademark} (Cell/B.E.). Automatic speech recognition decodes speech samples into plain text (other representations are possible) and must process samples at real-time rates. Fortunately, the computational tasks involved in this pipeline are highly data-parallel and can receive significant hardware acceleration from vector-streaming architectures such as the Cell/B.E. Identifying and exploiting these parallelism opportunities is challenging, but also critical to improving system performance. We observed, from our initial performance timings, that a single Cell/B.E. processor can recognize speech from thousands of simultaneous voice channels in real time--a channel density that is orders-of-magnitude greater than the capacity of existing software speech recognizers based on CPUs (central processing units). This result emphasizes the potential for Cell/B.E.-based speech recognition and will likely lead to the future development of production speech systems using Cell/B.E. clusters.

Thermocouple-based Temperature Sensing System for Chemical Cell Inside Micro UAV Device

Science.gov (United States)

Han, Yanhui; Feng, Yue; Lou, Haozhe; Zhang, Xinzhao

2018-03-01

Environmental temperature of UAV system is crucial for chemical cell component inside. Once the temperature of this chemical cell is over 259 °C and keeps more than 20 min, the high thermal accumulation would result in an explosion, which seriously damage the whole UAV system. Therefore, we develop a micro temperature sensing system for monitoring the temperature of chemical cell thermally influenced by UAV device deployed in a 300 °C temperature environment, which is quite useful for insensitive munitions and UAV safety enhancement technologies.

Systems Biology and Stem Cell Pluripotency

DEFF Research Database (Denmark)

Mashayekhi, Kaveh; Hall, Vanessa Jane; Freude, Kristine

2016-01-01

Recent breakthroughs in stem cell biology have accelerated research in the area of regenerative medicine. Over the past years, it has become possible to derive patient-specific stem cells which can be used to generate different cell populations for potential cell therapy. Systems biological...... modeling of stem cell pluripotency and differentiation have largely been based on prior knowledge of signaling pathways, gene regulatory networks, and epigenetic factors. However, there is a great need to extend the complexity of the modeling and to integrate different types of data, which would further...... improve systems biology and its uses in the field. In this chapter, we first give a general background on stem cell biology and regenerative medicine. Stem cell potency is introduced together with the hierarchy of stem cells ranging from pluripotent embryonic stem cells (ESCs) and induced pluripotent stem...

Fuel Cells: Power System Option for Space Research

Science.gov (United States)

Shaneeth, M.; Mohanty, Surajeet

2012-07-01

Fuel Cells are direct energy conversion devices and, thereby, they deliver electrical energy at very high efficiency levels. Hydrogen and Oxygen gases are electrochemically processed, producing clean electric power with water as the only by product. A typical, Fuel Cell based power system involve a Electrochemical power converter, gas storage and management systems, thermal management systems and relevant control units. While there exists different types of Fuel cells, Proton Exchange Membrane (PEM) Fuel Cells are considered as the most suitable one for portable applications. Generally, Fuel Cells are considered as the primary power system option in space missions requiring high power ( > 5kW) and long durations and also where water is a consumable, such as manned missions. This is primarily due to the advantage that fuel cell based power systems offer, in terms of specific energy. Fuel cells have the potential to attain specific energy > 500Wh/kg, specific power >500W/kg, energy density > 400Whr/L and also power density > 200 W/L. This apart, a fuel cell system operate totally independent of sun light, whereas as battery based system is fully dependent on the same. This uniqueness provides added flexibility and capabilities to the missions and modularity for power system. High power requiring missions involving reusable launch vehicles, manned missions etc are expected to be richly benefited from this. Another potential application of Fuel Cell would be interplanetary exploration. Unpredictable and dusty atmospheres of heavenly bodies limits sun light significantly and there fuel cells of different types, eg, Bio-Fuel Cells, PEMFC, DMFCs would be able to work effectively. Manned or unmanned lunar out post would require continuous power even during extra long lunar nights and high power levels are expected. Regenerative Fuel Cells, a combination of Fuel Cells and Electrolysers, are identified as strong candidate. While application of Fuel Cells in high power

Performance analysis of a potassium-base AMTEC cell

International Nuclear Information System (INIS)

Huang, C.; Hendricks, T.J.; Hunt, T.K.

1998-01-01

Sodium-BASE Alkali-Metal-Thermal-to-Electric-Conversion (AMTEC) cells have been receiving increased attention and funding from the Department of Energy, NASA and the United States Air Force. Recently, sodium-BASE (Na-BASE) AMTEC cells were selected for the Advanced Radioisotope Power System (ARPS) program for the next generation of deep-space missions and spacecraft. Potassium-BASE (K-BASE) AMTEC cells have not received as much attention to date, even though the vapor pressure of potassium is higher than that of sodium at the same temperature. So that, K-BASE AMTEC cells with potentially higher open circuit voltage and higher power output than Na-BASE AMTEC cells are possible. Because the surface tension of potassium is about half of the surface tension of sodium at the same temperature, the artery and evaporator design in a potassium AMTEC cell has much more challenging pore size requirements than designs using sodium. This paper uses a flexible thermal/fluid/electrical model to predict the performance of a K-BASE AMTEC cell. Pore sizes in the artery of K-BASE AMTEC cells must be smaller by an order of magnitude than in Na-BASE AMTEC cells. The performance of a K-BASE AMTEC cell was higher than a Na-BASE AMTEC cell at low voltages/high currents. K-BASE AMTEC cells also have the potential of much better electrode performance, thereby creating another avenue for potentially better performance in K-BASE AMTEC cells

Improved Academic Performance and Student Perceptions of Learning through Use of a Cell Phone-Based Personal Response System

Science.gov (United States)

Ma, Sihui; Steger, Daniel G.; Doolittle, Peter E.; Stewart, Amanda C.

2018-01-01

Personal response systems, such as clickers, have been widely used to improve the effectiveness of teaching in various classroom settings. Although hand-held clicker response systems have been the subject of multiple prior studies, few studies have focused on the use of cell phone-based personal response system (CPPRS) specifically. This study…

A new procedure for estimating the cell temperature of a high concentrator photovoltaic grid connected system based on atmospheric parameters

International Nuclear Information System (INIS)

Fernández, Eduardo F.; Almonacid, Florencia

2015-01-01

Highlights: • Concentrating grid-connected systems are working at maximum power point. • The operating cell temperature is inherently lower than at open circuit. • Two novel methods for estimating the cell temperature are proposed. • Both predict the operating cell temperature from atmospheric parameters. • Experimental results show that both methods perform effectively. - Abstract: The working cell temperature of high concentrator photovoltaic systems is a crucial parameter when analysing their performance and reliability. At the same time, due to the special features of this technology, the direct measurement of the cell temperature is very complex and is usually obtained by using different indirect methods. High concentrator photovoltaic modules in a system are operating at maximum power since they are connected to an inverter. So that, their cell temperature is lower than the cell temperature of a module at open-circuit voltage since an important part of the light power density is converted into electricity. In this paper, a procedure for indirectly estimating the cell temperature of a high concentrator photovoltaic system from atmospheric parameters is addressed. Therefore, this new procedure has the advantage that is valid for estimating the cell temperature of a system at any location of interest if the atmospheric parameters are available. To achieve this goal, two different methods are proposed: one based on simple mathematical relationships and another based on artificial intelligent techniques. Results show that both methods predicts the cell temperature of a module connected to an inverter with a low margin of error with a normalised root mean square error lower or equal than 3.3%, an absolute root mean square error lower or equal than 2 °C, a mean absolute error lower or equal then 1.5 °C, and a mean bias error and a mean relative error almost equal to 0%

First experience with particle-in-cell plasma physics code on ARM-based HPC systems

Science.gov (United States)

Sáez, Xavier; Soba, Alejandro; Sánchez, Edilberto; Mantsinen, Mervi; Mateo, Sergi; Cela, José M.; Castejón, Francisco

2015-09-01

In this work, we will explore the feasibility of porting a Particle-in-cell code (EUTERPE) to an ARM multi-core platform from the Mont-Blanc project. The used prototype is based on a system-on-chip Samsung Exynos 5 with an integrated GPU. It is the first prototype that could be used for High-Performance Computing (HPC), since it supports double precision and parallel programming languages.

A gas circulation and purification system for gas-cell-based low-energy RI-beam production

Energy Technology Data Exchange (ETDEWEB)

Sonoda, T.; Wada, M.; Katayama, I.; Kojima, T. M.; Reponen, M. [RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tsubota, T. [Tokyo KOATSU Co., Ltd., 1-9-8 Shibuya, Shibuyaku, Tokyo 150-0002 (Japan)

2016-06-15

A gas circulation and purification system was developed at the RIKEN Radioactive Isotope Beam Factory that can be used for gas-cell-based low-energy RI-beam production. A high-flow-rate gas cell filled with one atmosphere of buffer gas (argon or helium) is used for the deceleration and thermalization of high-energy RI-beams. The exhausted buffer gas is efficiently collected using a compact dry pump and returned to the gas cell with a recovery efficiency of >97%. The buffer gas is efficiently purified using two gas purifiers as well as collision cleaning, which eliminates impurities in the gas. An impurity level of one part per billion is achieved with this method.

Cell-Phone Tower Power System Prototype Testing for Verizon Wireless |

Science.gov (United States)

Advanced Manufacturing Research | NREL Cell-Phone Tower Power System Prototype Testing for Verizon Wireless Cell-Phone Tower Power System Prototype Testing for Verizon Wireless For Verizon Wireless , NREL tested a new cell-phone tower power system prototype based on DC interconnection and photovoltaics

Fuel cell system economics: comparing the costs of generating power with stationary and motor vehicle PEM fuel cell systems

International Nuclear Information System (INIS)

Lipman, Timothy E.; Edwards, Jennifer L.; Kammen, Daniel M.

2004-01-01

This investigation examines the economics of producing electricity from proton-exchange membrane (PEM) fuel cell systems under various conditions, including the possibility of using fuel cell vehicles (FCVs) to produce power when they are parked at office buildings and residences. The analysis shows that the economics of both stationary fuel cell and FCV-based power vary significantly with variations in key input variables such as the price of natural gas, electricity prices, fuel cell and reformer system costs, and fuel cell system durability levels. The 'central case' results show that stationary PEM fuel cell systems can supply electricity for offices and homes in California at a net savings when fuel cell system costs reach about $6000 for a 5 kW home system ($1200/kW) and $175,000 for a 250 kW commercial system ($700/kW) and assuming somewhat favorable natural gas costs of $6/GJ at residences and $4/GJ at commercial buildings. Grid-connected FCVs in commercial settings can also potentially supply electricity at competitive rates, in some cases producing significant annual benefits. Particularly attractive is the combination of net metering along with time-of-use electricity rates that allow power to be supplied to the utility grid at the avoided cost of central power plant generation. FCV-based power at individual residences does not appear to be as attractive, at least where FCV power can only be used directly or banked with the utility for net metering and not sold in greater quantity, due to the low load levels at these locations that provide a poor match to automotive fuel cell operation, higher natural gas prices than are available at commercial settings, and other factors

Analysis and performance assessment of a new solar-based multigeneration system integrated with ammonia fuel cell and solid oxide fuel cell-gas turbine combined cycle

Science.gov (United States)

Siddiqui, Osamah; Dincer, Ibrahim

2017-12-01

In the present study, a new solar-based multigeneration system integrated with an ammonia fuel cell and solid oxide fuel cell-gas turbine combined cycle to produce electricity, hydrogen, cooling and hot water is developed for analysis and performance assessment. In this regard, thermodynamic analyses and modeling through both energy and exergy approaches are employed to assess and evaluate the overall system performance. Various parametric studies are conducted to study the effects of varying system parameters and operating conditions on the energy and exergy efficiencies. The results of this study show that the overall multigeneration system energy efficiency is obtained as 39.1% while the overall system exergy efficiency is calculated as 38.7%, respectively. The performance of this multigeneration system results in an increase of 19.3% in energy efficiency as compared to single generation system. Furthermore, the exergy efficiency of the multigeneration system is 17.8% higher than the single generation system. Moreover, both energy and exergy efficiencies of the solid oxide fuel cell-gas turbine combined cycle are determined as 68.5% and 55.9% respectively.

Generation of Human Induced Pluripotent Stem Cells Using RNA-Based Sendai Virus System and Pluripotency Validation of the Resulting Cell Population.

Science.gov (United States)

Chichagova, Valeria; Sanchez-Vera, Irene; Armstrong, Lyle; Steel, David; Lako, Majlinda

2016-01-01

Human induced pluripotent stem cells (hiPSCs) provide a platform for studying human disease in vitro, increase our understanding of human embryonic development, and provide clinically relevant cell types for transplantation, drug testing, and toxicology studies. Since their discovery, numerous advances have been made in order to eliminate issues such as vector integration into the host genome, low reprogramming efficiency, incomplete reprogramming and acquisition of genomic instabilities. One of the ways to achieve integration-free reprogramming is by using RNA-based Sendai virus. Here we describe a method to generate hiPSCs with Sendai virus in both feeder-free and feeder-dependent culture systems. Additionally, we illustrate methods by which to validate pluripotency of the resulting stem cell population.

Cell-based therapeutic strategies for multiple sclerosis

DEFF Research Database (Denmark)

Scolding, Neil J; Pasquini, Marcelo; Reingold, Stephen C

2017-01-01

and none directly promotes repair. Cell-based therapies, including immunoablation followed by autologous haematopoietic stem cell transplantation, mesenchymal and related stem cell transplantation, pharmacologic manipulation of endogenous stem cells to enhance their reparative capabilities......, and transplantation of oligodendrocyte progenitor cells, have generated substantial interest as novel therapeutic strategies for immune modulation, neuroprotection, or repair of the damaged central nervous system in multiple sclerosis. Each approach has potential advantages but also safety concerns and unresolved...

Modeling and optimization for proton exchange membrane fuel cell stack using aging and challenging P systems based optimization algorithm

International Nuclear Information System (INIS)

Yang, Shipin; Chellali, Ryad; Lu, Xiaohua; Li, Lijuan; Bo, Cuimei

2016-01-01

Accurate models of PEM (proton exchange membrane) fuel cells are of great significance for the analysis and the control for power generation. We present a new semi-empirical model to predict the voltage outputs of PEM fuel cell stacks. We also introduce a new estimation method, called AC-POA (aging and challenging P systems based optimization algorithm) allowing deriving the parameters of the semi-empirical model. In our model, the cathode inlet pressure is selected as an additional factor to modify the expression of concentration over-voltage V con for traditional Amphlett's PEM fuel cell model. In AC-POA, the aging-mechanism inspired object updating rule is merged in existing P system. We validate through experiments the effectiveness of AC-POA and the fitting accuracy of our model. Modeling comparison results show that the predictions of our model are the best in terms of fitting to actual sample data. - Highlights: • Presented a p c -based modificatory semi-empirical model for PEMFC stack. • Introduced a new aging inspired improved parameter estimation algorithm, AC-POA. • Validated the effectiveness of the AC-POA and the new model. • Remodeled the practical PEM fuel cell system.

Systemic Administration of Interleukin 2 Enhances the Therapeutic Efficacy of Dendritic Cell-Based Tumor Vaccines

Science.gov (United States)

Shimizu, K.; Fields, R. C.; Giedlin, M.; Mule, J. J.

1999-03-01

We have reported previously that murine bone marrow-derived dendritic cells (DC) pulsed with whole tumor lysates can mediate potent antitumor immune responses both in vitro and in vivo. Because successful therapy was dependent on host immune T cells, we have now evaluated whether the systemic administration of the T cell stimulatory/growth promoting cytokine interleukin-2 (IL-2) could enhance tumor lysate-pulsed DC-based immunizations to further promote protective immunity toward, and therapeutic rejection of, syngeneic murine tumors. In three separate approaches using a weakly immunogenic sarcoma (MCA-207), the systemic administration of non-toxic doses of recombinant IL-2 (20,000 and 40,000 IU/dose) was capable of mediating significant increases in the potency of DC-based immunizations. IL-2 could augment the efficacy of tumor lysate-pulsed DC to induce protective immunity to lethal tumor challenge as well as enhance splenic cytotoxic T lymphocyte activity and interferon-γ production in these treated mice. Moreover, treatment with the combination of tumor lysate-pulsed DC and IL-2 could also mediate regressions of established pulmonary 3-day micrometastases and 7-day macrometastases as well as established 14- and 28-day s.c. tumors, leading to either significant cure rates or prolongation in overall survival. Collectively, these findings show that nontoxic doses of recombinant IL-2 can potentiate the antitumor effects of tumor lysate-pulsed DC in vivo and provide preclinical rationale for the use of IL-2 in DC-based vaccine strategies in patients with advanced cancer.

Rescue the failed half-ZFN by a sensitive mammalian cell-based luciferase reporter system.

Directory of Open Access Journals (Sweden)

Weifeng Zhang

Full Text Available ZFN technology is a powerful research tool and has been used for genome editing in cells lines, animals and plants. The generation of functional ZFNs for particular targets in mammalian genome is still challenging for an average research group. The modular-assembly method is relatively fast, easy-to-practice but has a high failure rate. Some recent studies suggested that a ZFP with low binding activity might be able to form a working ZFN pair with another binding active half-ZFP. In order to unveil the potential ZFP candidates among those with low binding activities, this paper established a highly sensitive mammalian cell-based transcriptional reporter system to assess the DNA binding activities of ZFPs by inserting multiple copies of ZFN target sequence fragment (TSF of an interested gene (e. g., hPGRN or hVEGF. Our results showed that this system increased the screening sensitivity up to 50-fold and markedly amplified the differences in the binding activities between different ZFPs. We also found that the targeted chromosomal gene repair efficiency of each hPGRN or hVEGF ZFN pair was in proportion with the combination of the binding activities of the ZFL (Left zinc finger and ZFR (Right zinc finger. A hPGRN ZFR with low binding ability was able to form a biological active ZFN if combined with a hPGRN ZFL with relatively high binding ability. Lastly, site-specific genome editing by hPGRN ZFNs generated by this system was confirmed by sequencing, and the PGRN knock-out cell line showed significantly decreased cell growth compared with the control. Our system will provide a valuable tool for further optimizing the nucleases with regard to specificity and cytotoxicity.

A new method using insert-based systems (IBS) to improve cell behavior study on flexible and rigid biomaterials

OpenAIRE

Grenade, Charlotte; Moniotte, Nicolas; Rompen, Eric; Vanheusden, Alain; Mainjot, Amélie; De Pauw-Gillet, Marie-Claire

2016-01-01

In vitro studies about biomaterials biological properties are essential screening tests. Yet cell cultures encounter difficulties related to cell retention on material surface or to the observation of both faces of permeable materials. The objective of the present study was to develop a reliable in vitro method to study cell behavior on rigid and flexible/permeable biomaterials elaborating two specific insert-based systems (IBS-R and IBS-F respectively). IBS-R was designed as a specific cylin...

A reversible electrolyzer-fuel cell system based on PEM technology

International Nuclear Information System (INIS)

Grigoriev, S.A.; Millet, P.; Fateev, V.N.

2009-01-01

'Full text': A reversible electrolyzer-fuel cell is an electrochemical system which can be alternatively operated in water electrolysis or H 2 /O 2 (air) fuel cell modes. Whereas proton-exchange membrane (PEM) water electrolysis and PEM fuel cell technologies are individually well-established, it is still a very challenging task to develop efficient reversible systems which can maintain interesting electrochemical performances during a significant number of cycles. Results reported in this communication are related to R and D on bi-functional catalysts, electrocatalytic layers, gas diffusion layers/current collectors and reversible PEM stack design. Electrodes which do not change their redox status when the operation mode of the cell is switched from electrolysis to fuel cell are more specifically considered. In particular, it is shown that, when the anode is composed of Pt-Ir layers (ca. 0.5/0.5 wt. ratio), best electrochemical performances are obtained (for both for water and hydrogen oxidation reactions) when an Ir layer is placed face-to-face with the membrane. Cathodic electrocatalytic layers made of Pt/C were prepared and optimized by adding PTFE to obtain the required hydrophobic-hydrophilic properties for effective oxygen and protons electro-reduction. Gas diffusion electrodes made of porous carbon materials and bi-porous titanium sheets with appropriate water management properties have also been developed. A two-cell stack with 250 cm 2 active area electrodes has been assembled using the optimized components and successfully tested. Results are rather close to those obtained for individual water electrolysis and H 2 /O 2 fuel cells with the same noble metal loadings and similar operating conditions. For instance, at a current density of 0.2 A/cm 2 , typical cell voltages of ca. 1.55 and 0.70 V were respectively obtained during water electrolysis and H 2 /O 2 fuel cell operation, using Nafion-1135 as solid polymer electrolyte and noble metal loadings 2

[CRISPR/Cas system for genome editing in pluripotent stem cells].

Science.gov (United States)

Vasil'eva, E A; Melino, D; Barlev, N A

2015-01-01

Genome editing systems based on site-specific nucleases became very popular for genome editing in modern bioengineering. Human pluripotent stem cells provide a unique platform for genes function study, disease modeling, and drugs testing. Consequently, technology for fast, accurate and well controlled genome manipulation is required. CRISPR/Cas (clustered regularly interspaced short palindromic repeat/CRISPR-associated) system could be employed for these purposes. This system is based on site-specific programmable nuclease Cas9. Numerous advantages of the CRISPR/Cas system and its successful application to human stem cells provide wide opportunities for genome therapy and regeneration medicine. In this publication, we describe and compare the main genome editing systems based on site-specific programmable nucleases and discuss opportunities and perspectives of the CRISPR/Cas system for application to pluripotent stem cells.

Virtual reality based support system for layout planning and programming of an industrial robotic work cell.

Directory of Open Access Journals (Sweden)

Hwa Jen Yap

Full Text Available Traditional robotic work cell design and programming are considered inefficient and outdated in current industrial and market demands. In this research, virtual reality (VR technology is used to improve human-robot interface, whereby complicated commands or programming knowledge is not required. The proposed solution, known as VR-based Programming of a Robotic Work Cell (VR-Rocell, consists of two sub-programmes, which are VR-Robotic Work Cell Layout (VR-RoWL and VR-based Robot Teaching System (VR-RoT. VR-RoWL is developed to assign the layout design for an industrial robotic work cell, whereby VR-RoT is developed to overcome safety issues and lack of trained personnel in robot programming. Simple and user-friendly interfaces are designed for inexperienced users to generate robot commands without damaging the robot or interrupting the production line. The user is able to attempt numerous times to attain an optimum solution. A case study is conducted in the Robotics Laboratory to assemble an electronics casing and it is found that the output models are compatible with commercial software without loss of information. Furthermore, the generated KUKA commands are workable when loaded into a commercial simulator. The operation of the actual robotic work cell shows that the errors may be due to the dynamics of the KUKA robot rather than the accuracy of the generated programme. Therefore, it is concluded that the virtual reality based solution approach can be implemented in an industrial robotic work cell.

Virtual reality based support system for layout planning and programming of an industrial robotic work cell.

Science.gov (United States)

Yap, Hwa Jen; Taha, Zahari; Dawal, Siti Zawiah Md; Chang, Siow-Wee

2014-01-01

Traditional robotic work cell design and programming are considered inefficient and outdated in current industrial and market demands. In this research, virtual reality (VR) technology is used to improve human-robot interface, whereby complicated commands or programming knowledge is not required. The proposed solution, known as VR-based Programming of a Robotic Work Cell (VR-Rocell), consists of two sub-programmes, which are VR-Robotic Work Cell Layout (VR-RoWL) and VR-based Robot Teaching System (VR-RoT). VR-RoWL is developed to assign the layout design for an industrial robotic work cell, whereby VR-RoT is developed to overcome safety issues and lack of trained personnel in robot programming. Simple and user-friendly interfaces are designed for inexperienced users to generate robot commands without damaging the robot or interrupting the production line. The user is able to attempt numerous times to attain an optimum solution. A case study is conducted in the Robotics Laboratory to assemble an electronics casing and it is found that the output models are compatible with commercial software without loss of information. Furthermore, the generated KUKA commands are workable when loaded into a commercial simulator. The operation of the actual robotic work cell shows that the errors may be due to the dynamics of the KUKA robot rather than the accuracy of the generated programme. Therefore, it is concluded that the virtual reality based solution approach can be implemented in an industrial robotic work cell.

Virtual Reality Based Support System for Layout Planning and Programming of an Industrial Robotic Work Cell

Science.gov (United States)

Yap, Hwa Jen; Taha, Zahari; Md Dawal, Siti Zawiah; Chang, Siow-Wee

2014-01-01

Traditional robotic work cell design and programming are considered inefficient and outdated in current industrial and market demands. In this research, virtual reality (VR) technology is used to improve human-robot interface, whereby complicated commands or programming knowledge is not required. The proposed solution, known as VR-based Programming of a Robotic Work Cell (VR-Rocell), consists of two sub-programmes, which are VR-Robotic Work Cell Layout (VR-RoWL) and VR-based Robot Teaching System (VR-RoT). VR-RoWL is developed to assign the layout design for an industrial robotic work cell, whereby VR-RoT is developed to overcome safety issues and lack of trained personnel in robot programming. Simple and user-friendly interfaces are designed for inexperienced users to generate robot commands without damaging the robot or interrupting the production line. The user is able to attempt numerous times to attain an optimum solution. A case study is conducted in the Robotics Laboratory to assemble an electronics casing and it is found that the output models are compatible with commercial software without loss of information. Furthermore, the generated KUKA commands are workable when loaded into a commercial simulator. The operation of the actual robotic work cell shows that the errors may be due to the dynamics of the KUKA robot rather than the accuracy of the generated programme. Therefore, it is concluded that the virtual reality based solution approach can be implemented in an industrial robotic work cell. PMID:25360663

Upgrading versus reforming: an energy and exergy analysis of two Solid Oxide Fuel Cell-based systems for a convenient biogas-to-electricity conversion

International Nuclear Information System (INIS)

Baldinelli, A.; Barelli, L.; Bidini, G.

2017-01-01

Highlights: • Biogas-to-electricity conversion through Solid Oxide Fuel Cell is investigated. • Two solutions are compared for biogas-to-electricity conversion. • Direct feeding by partially upgraded biogas meets with fuel cell long operation. • Best energy and exergy performances are obtained with an innovative system-design. • A sensitivity analysis on the process parameters determines its convenience margin. - Abstract: Aiming at designing biogas-to-electricity advanced systems, Solid Oxide Fuel Cells are promising candidates. They benefit from scalability on plant sizes that suit anaerobic digesters potentialities. For biogas-Solid Oxide Fuel Cells applications, the implementation of an external pre-reformer is usually considered. However, the possibility to perform direct fuel feeding to the Solid Oxide Fuel Cell offers new opportunities towards the realization of lean systems, which are competitive especially on small-scale installations (i.e. on-farm biogas-to-electricity conversion). In this frame, scientific literature is rather poor and, to cover this gap, system simulations are called for two reasons: first, to demonstrate the potential efficiency gain of new concepts; second, to provide a meaningful support for long-term experimental investigation on Solid Oxide Fuel Cells operated upon direct feeding of unreformed biogas. For that, the current study compares two system designs for biogas utilization into Solid Oxide Fuel Cells. The conventional one realizes biogas steam reforming prior the fuel cell, while the novel concept is based on direct feeding of partially upgraded biogas by means of carbon dioxide-separation membranes. As main outcome of the study, the system equipped with carbon dioxide-separation membranes achieves better performances than its conventional competitor does, scoring 51.1% energy efficiency and 52.3% exergy efficiency (compared to 37.2% and 38.6% respectively exhibited by the reformer-based system). Because of the lack

Potential of stem cell based therapy and tissue engineering in the regeneration of the central nervous system

International Nuclear Information System (INIS)

An Yihua; Tsang, Kent K S; Zhang Han

2006-01-01

The insufficiency of self-repair and regeneration of the central nervous system (CNS) leads to difficulty of rehabilitation of the injured brain. In the past few decades, the significant progress in cell therapy and tissue engineering has contributed to the functional recovery of the CNS to a great extent. The present review focuses on the potential role of stem cell based therapy and tissue engineering in the regeneration of the CNS. (topical review)

Portable 25W hybrid fuel cell system

International Nuclear Information System (INIS)

Green, K.; Slee, R.; Tilley, J.

2003-01-01

Increased operating periods for portable electrical equipment are driving the development of battery and fuel cell technologies. Fuel cell systems promise greater endurance than battery based systems, and this paper describes the research into, and design of, a hybrid lithium-ion battery / fuel cell power source. The device is primarily aimed at military applications such as powering army radio sets and the UK MoD's Integrated Soldier Technology (IST) programme, but would be equally suitable as a power source for civilian applications such as camcorders, battery chargers etc. The air-breathing fuel cell comprises low cost, robust components, and a single cell is capable of developing >0.5W cm -2 . This power rating, however, is reduced in a stack where heat rejection becomes a critical issue. The stack design lends itself to facile manufacture, and the stack can be assembled in minutes by simply stacking the components into place. The remainder of the system includes two lithium-ion battery packs which provide start-up and shutdown power, and enable a silent-operating mode, during which the fuel cell is powered down, to be selected. The intelligent, electronic control, based upon an embedded RISC microprocessor, ensures safe operation and the recharge of the batteries. The overall system is capable of delivering 25W continuous power at an operating voltage of 12V dc. Preliminary testing results are reported. Advantages of this system include a relatively high gravimetric power density, load-following operation and the confidence of a high performance battery as an emergency backup. (author)

Systems biology approach to developing S2RM-based ＂systemstherapeutics＂ and naturally induced pluripotent stem cells

Institute of Scientific and Technical Information of China (English)

2015-01-01

The degree to, and the mechanisms through, whichstem cells are able to build, maintain, and heal the bodyhave only recently begun to be understood. Much of thestem cell＇s power resides in the release of a multitudeof molecules, called stem cell released molecules （SRM）.A fundamentally new type of therapeutic, namely＂systems therapeutic＂, can be realized by reverseengineering the mechanisms of the SRM processes.Recent data demonstrates that the composition of theSRM is different for each type of stem cell, as well asfor different states of each cell type. Although systemsbiology has been successfully used to analyze multiplepathways, the approach is often used to develop a smallmolecule interacting at only one pathway in the system.A new model is emerging in biology where systemsbiology is used to develop a new technology actingat multiple pathways called ＂systems therapeutics＂. Anatural set of healing pathways in the human that usesSRM is instructive and of practical use in developingsystems therapeutics. Endogenous SRM processes inthe human body use a combination of SRM from twoor more stem cell types, designated as S2RM, doing sounder various state dependent conditions for each celltype. Here we describe our approach in using statedependentSRM from two or more stem cell types,S2RM technology, to develop a new class of therapeuticscalled ＂systems therapeutics.＂ Given the ubiquitous andpowerful nature of innate S2RM-based healing in thehuman body, this ＂systems therapeutic＂ approach usingS2RM technology will be important for the developmentof anti-cancer therapeutics, antimicrobials, woundcare products and procedures, and a number of othertherapeutics for many indications.

Stem and Progenitor Cell-Based Therapy of the Central Nervous System

DEFF Research Database (Denmark)

Goldman, Steven A.

2016-01-01

A variety of neurological disorders are attractive targets for stem and progenitor cell-based therapy. Yet many conditions are not, whether by virtue of an inhospitable disease environment, poorly understood pathophysiology, or poor alignment of donor cell capabilities with patient needs. Moreove...

Fuel cell-based CHP system modelling using Artificial Neural Networks aimed at developing techno-economic efficiency maximization control systems

International Nuclear Information System (INIS)

Asensio, F.J.; San Martín, J.I.; Zamora, I.; Garcia-Villalobos, J.

2017-01-01

This paper focuses on the modelling of the performance of a Polymer Electrolyte Membrane Fuel Cell (PEMFC)-based cogeneration system to integrate it in hybrid and/or connected to grid systems and enable the optimization of the techno-economic efficiency of the system in which it is integrated. To this end, experimental tests on a PEMFC-based cogeneration system of 600 W of electrical power have been performed to train an Artificial Neural Network (ANN). Once the learning of the ANN, it has been able to emulate real operating conditions, such as the cooling water out temperature and the hydrogen consumption of the PEMFC depending on several variables, such as the electric power demanded, temperature of the inlet water flow to the cooling circuit, cooling water flow and the heat demanded to the CHP system. After analysing the results, it is concluded that the presented model reproduces with enough accuracy and precision the performance of the experimented PEMFC, thus enabling the use of the model and the ANN learning methodology to model other PEMFC-based cogeneration systems and integrate them in techno-economic efficiency optimization control systems. - Highlights: • The effect of the energy demand variation on the PEMFC's efficiency is predicted. • The model relies on experimental data obtained from a 600 W PEMFC. • It provides the temperature and the hydrogen consumption with good accuracy. • The range in which the global energy efficiency could be improved is provided.

Towards a defined ECM and small molecule based monolayer culture system for the expansion of mouse and human intestinal stem cells.

Science.gov (United States)

Tong, Zhixiang; Martyn, Keir; Yang, Andy; Yin, Xiaolei; Mead, Benjamin E; Joshi, Nitin; Sherman, Nicholas E; Langer, Robert S; Karp, Jeffrey M

2018-02-01

Current ISC culture systems face significant challenges such as animal-derived or undefined matrix compositions, batch-to-batch variability (e.g. Matrigel-based organoid culture), and complexity of assaying cell aggregates such as organoids which renders the research and clinical translation of ISCs challenging. Here, through screening for suitable ECM components, we report a defined, collagen based monolayer culture system that supports the growth of mouse and human intestinal epithelial cells (IECs) enriched for an Lgr5 + population comparable or higher to the levels found in a standard Matrigel-based organoid culture. The system, referred to as the Bolstering Lgr5 Transformational (BLT) Sandwich culture, comprises a collagen IV-coated porous substrate and a collagen I gel overlay which sandwich an IEC monolayer in between. The distinct collagen cues synergistically regulate IEC attachment, proliferation, and Lgr5 expression through maximizing the engagement of distinct cell surface adhesion receptors (i.e. integrin α2β1, integrin β4) and cell polarity. Further, we apply our BLT Sandwich system to identify that the addition of a bone morphogenetic protein (BMP) receptor inhibitor (LDN-193189) improves the expansion of Lgr5-GFP + cells from mouse small intestinal crypts by nearly 2.5-fold. Notably, the BLT Sandwich culture is capable of expanding human-derived IECs with higher LGR5 mRNA levels than conventional Matrigel culture, providing superior expansion of human LGR5 + ISCs. Considering the key roles Lgr5 + ISCs play in intestinal epithelial homeostasis and regeneration, we envision that our BLT Sandwich culture system holds great potential for understanding and manipulating ISC biology in vitro (e.g. for modeling ISC-mediated gut diseases) or for expanding a large number of ISCs for clinical utility (e.g. for stem cell therapy). Copyright © 2017 Elsevier Ltd. All rights reserved.

Rule-based modeling: a computational approach for studying biomolecular site dynamics in cell signaling systems

Science.gov (United States)

Chylek, Lily A.; Harris, Leonard A.; Tung, Chang-Shung; Faeder, James R.; Lopez, Carlos F.

2013-01-01

Rule-based modeling was developed to address the limitations of traditional approaches for modeling chemical kinetics in cell signaling systems. These systems consist of multiple interacting biomolecules (e.g., proteins), which themselves consist of multiple parts (e.g., domains, linear motifs, and sites of phosphorylation). Consequently, biomolecules that mediate information processing generally have the potential to interact in multiple ways, with the number of possible complexes and post-translational modification states tending to grow exponentially with the number of binary interactions considered. As a result, only large reaction networks capture all possible consequences of the molecular interactions that occur in a cell signaling system, which is problematic because traditional modeling approaches for chemical kinetics (e.g., ordinary differential equations) require explicit network specification. This problem is circumvented through representation of interactions in terms of local rules. With this approach, network specification is implicit and model specification is concise. Concise representation results in a coarse graining of chemical kinetics, which is introduced because all reactions implied by a rule inherit the rate law associated with that rule. Coarse graining can be appropriate if interactions are modular, and the coarseness of a model can be adjusted as needed. Rules can be specified using specialized model-specification languages, and recently developed tools designed for specification of rule-based models allow one to leverage powerful software engineering capabilities. A rule-based model comprises a set of rules, which can be processed by general-purpose simulation and analysis tools to achieve different objectives (e.g., to perform either a deterministic or stochastic simulation). PMID:24123887

Rule-based modeling: a computational approach for studying biomolecular site dynamics in cell signaling systems.

Science.gov (United States)

Chylek, Lily A; Harris, Leonard A; Tung, Chang-Shung; Faeder, James R; Lopez, Carlos F; Hlavacek, William S

2014-01-01

Rule-based modeling was developed to address the limitations of traditional approaches for modeling chemical kinetics in cell signaling systems. These systems consist of multiple interacting biomolecules (e.g., proteins), which themselves consist of multiple parts (e.g., domains, linear motifs, and sites of phosphorylation). Consequently, biomolecules that mediate information processing generally have the potential to interact in multiple ways, with the number of possible complexes and posttranslational modification states tending to grow exponentially with the number of binary interactions considered. As a result, only large reaction networks capture all possible consequences of the molecular interactions that occur in a cell signaling system, which is problematic because traditional modeling approaches for chemical kinetics (e.g., ordinary differential equations) require explicit network specification. This problem is circumvented through representation of interactions in terms of local rules. With this approach, network specification is implicit and model specification is concise. Concise representation results in a coarse graining of chemical kinetics, which is introduced because all reactions implied by a rule inherit the rate law associated with that rule. Coarse graining can be appropriate if interactions are modular, and the coarseness of a model can be adjusted as needed. Rules can be specified using specialized model-specification languages, and recently developed tools designed for specification of rule-based models allow one to leverage powerful software engineering capabilities. A rule-based model comprises a set of rules, which can be processed by general-purpose simulation and analysis tools to achieve different objectives (e.g., to perform either a deterministic or stochastic simulation). © 2013 Wiley Periodicals, Inc.

Interference Alignment-based Precoding and User Selection with Limited Feedback in Two-cell Downlink Multi-user MIMO Systems

Directory of Open Access Journals (Sweden)

Yin Zhu

2016-05-01

Full Text Available Interference alignment (IA is a new approach to address interference in modern multiple-input multiple-out (MIMO cellular networks in which interference is an important factor that limits the system throughput. System throughput in most IA implementation schemes is significantly improved only with perfect channel state information and in a high signal-to-noise ratio (SNR region. Designing a simple IA scheme for the system with limited feedback and investigating system performance at a low-to-medium SNR region is important and practical. This paper proposed a precoding and user selection scheme based on partial interference alignment in two-cell downlink multi-user MIMO systems under limited feedback. This scheme aligned inter-cell interference to a predefined direction by designing user’s receive antenna combining vectors. A modified singular value decomposition (SVD-based beamforming method and a corresponding user-selection algorithm were proposed for the system with low rate limited feedback to improve sum rate performance. Simulation results show that the proposed scheme achieves a higher sum rate than traditional schemes without IA. The modified SVD-based beamforming scheme is also superior to the traditional zero-forcing beamforming scheme in low-rate limited feedback systems. The proposed partial IA scheme does not need to collaborate between transmitters and joint design between the transmitter and the users. The scheme can be implemented with low feedback overhead in current MIMO cellular networks.

Classification of cancerous cells based on the one-class problem approach

Science.gov (United States)

Murshed, Nabeel A.; Bortolozzi, Flavio; Sabourin, Robert

1996-03-01

One of the most important factors in reducing the effect of cancerous diseases is the early diagnosis, which requires a good and a robust method. With the advancement of computer technologies and digital image processing, the development of a computer-based system has become feasible. In this paper, we introduce a new approach for the detection of cancerous cells. This approach is based on the one-class problem approach, through which the classification system need only be trained with patterns of cancerous cells. This reduces the burden of the training task by about 50%. Based on this approach, a computer-based classification system is developed, based on the Fuzzy ARTMAP neural networks. Experimental results were performed using a set of 542 patterns taken from a sample of breast cancer. Results of the experiment show 98% correct identification of cancerous cells and 95% correct identification of non-cancerous cells.

Thermal System Modeling for Lunar and Martian Surface Regenerative Fuel Cell Systems

Science.gov (United States)

Gilligan, Ryan Patrick; Smith, Phillip James; Jakupca, Ian Joseph; Bennett, William Raymond; Guzik, Monica Christine; Fincannon, Homer J.

2017-01-01

The Advanced Exploration Systems (AES) Advanced Modular Power Systems (AMPS) Project is investigating different power systems for various lunar and Martian mission concepts. The AMPS Fuel Cell (FC) team has created two system-level models to evaluate the performance of regenerative fuel cell (RFC) systems employing different fuel cell chemistries. Proton Exchange Membrane fuel cells PEMFCs contain a polymer electrolyte membrane that separates the hydrogen and oxygen cavities and conducts hydrogen cations (protons) across the cell. Solid Oxide fuel cells (SOFCs) operate at high temperatures, using a zirconia-based solid ceramic electrolyte to conduct oxygen anions across the cell. The purpose of the modeling effort is to down select one fuel cell chemistry for a more detailed design effort. Figures of merit include the system mass, volume, round trip efficiency, and electrolyzer charge power required. PEMFCs operate at around 60 degrees Celsius versus SOFCs which operate at temperatures greater than 700 degrees Celsius. Due to the drastically different operating temperatures of the two chemistries the thermal control systems (TCS) differ. The PEM TCS is less complex and is characterized by a single pump cooling loop that uses deionized water coolant and rejects heat generated by the system to the environment via a radiator. The solid oxide TCS has its own unique challenges including the requirement to reject high quality heat and to condense the steam produced in the reaction. This paper discusses the modeling of thermal control systems for an extraterrestrial RFC that utilizes either a PEM or solid oxide fuel cell.

Nanoscale Relationship Between CD4 and CD25 of T Cells Visualized with NSOM/QD-Based Dual-Color Imaging System

Science.gov (United States)

Fan, Jinping; Lu, Xiaoxu; Liu, Shengde; Zhong, Liyun

2015-10-01

In this study, by using of near-field scanning optical microscopy (NSOM)/immune-labeling quantum dot (QD)-based dual-color imaging system, we achieved the direct visualization of nanoscale profiles for distribution and organization of CD4 and CD25 molecules in T cells. A novel and interesting finding was that though CD25 clustering as nanodomains were observed on the surface of CD4+CD25high regulatory T cells, these CD25 nanodomains were not co-localized with CD4 nanodomains. This result presented that the formation of these CD25 nanodomains on the surface of CD4+CD25high T cells were not associated with the response of T cell receptor (TCR)/CD3-dependent signal transduction. In contrast, on the surface of CD4+CD25low T cells, CD25 molecules distributed randomly without forming nanodomains while CD4 clustering as nanodomains can be observed; on the surface of CD8+CD25+ T cells, CD25 clustering as nanodomains and co-localization with CD8 nanodomains were observed. Collectively, above these results exhibited that TCR/CD3-based microdomains were indeed required for TCR/CD3-mediated T cells activation and enhanced the immune activity of CD4+CD25low T cells or CD8+CD25+ T cells. In particular, it was found that the formation of CD25 nanodomains and their segregation from TCR/CD3 microdomains were the intrinsic capability of CD4+CD25high T cells, suggesting this specific imaging feature of CD25 should be greatly associated with the regulatory activity of CD4+CD25high T cells. Importantly, this novel NSOM/QD-based dual-color imaging system will provide a useful tool for the research of distribution-function relationship of cell-surface molecules.

Implementing oxygen control in chip-based cell and tissue culture systems.

Science.gov (United States)

Oomen, Pieter E; Skolimowski, Maciej D; Verpoorte, Elisabeth

2016-09-21

Oxygen is essential in the energy metabolism of cells, as well as being an important regulatory parameter influencing cell differentiation and function. Interest in precise oxygen control for in vitro cultures of tissues and cells continues to grow, especially with the emergence of the organ-on-a-chip and the desire to emulate in vivo conditions. This was recently discussed in this journal in a Critical Review by Brennan et al. (Lab Chip (2014). DOI: ). Microfluidics can be used to introduce flow to facilitate nutrient supply to and waste removal from in vitro culture systems. Well-defined oxygen gradients can also be established. However, cells can quickly alter the oxygen balance in their vicinity. In this Tutorial Review, we expand on the Brennan paper to focus on the implementation of oxygen analysis in these systems to achieve continuous monitoring. Both electrochemical and optical approaches for the integration of oxygen monitoring in microfluidic tissue and cell culture systems will be discussed. Differences in oxygen requirements from one organ to the next are a challenging problem, as oxygen delivery is limited by its uptake into medium. Hence, we discuss the factors determining oxygen concentrations in solutions and consider the possible use of artificial oxygen carriers to increase dissolved oxygen concentrations. The selection of device material for applications requiring precise oxygen control is discussed in detail, focusing on oxygen permeability. Lastly, a variety of devices is presented, showing the diversity of approaches that can be employed to control and monitor oxygen concentrations in in vitro experiments.

Review on the Recent Developments of Photovoltaic Thermal (PV/T and Proton Exchange Membrane Fuel Cell (PEMFC Based Hybrid System

Directory of Open Access Journals (Sweden)

Zulkepli Afzam

2016-01-01

Full Text Available Photovoltaic Thermal (PV/T system emerged as one of the convenient type of renewable energy system acquire the ability to generate power and thermal energy in the absence of moving parts. However, the power output of PV/T is intermittent due to dependency on solar irradiation condition. Furthermore, its efficiency decreases because of cells instability at high temperature. On the other hand, fuel cell co-generation system (CGS is another technology that can generate power and heat simultaneously. Integration of PV/T and fuel cell CGS could enhance the reliability and sustainability of both systems as well as increasing the overall system performance. Hence, this paper intended to present the parameters that affect performance of PV/T and Proton Exchange Membrane Fuel Cell (PEMFC CGS. Moreover, recent developments on PV/T-fuel cell hybrid system are also presented. Based on literates, mass flow rate of moving fluid in PV/T was found to affect the system efficiency. For the PEMFC, when the heat is utilized, the system performance can be increased where the heat efficiency is similar to electrical efficiency which is about 50%. Recent developments of hybrid PV/T and fuel cell show that most of the studies only focus on the power generation of the system. There are less study on the both power and heat utilization which is indeed necessary in future development in term of operation strategy, optimization of size, and operation algorithm.

Microengineering methods for cell-based microarrays and high-throughput drug-screening applications

International Nuclear Information System (INIS)

Xu Feng; Wu Jinhui; Wang Shuqi; Gurkan, Umut Atakan; Demirci, Utkan; Durmus, Naside Gozde

2011-01-01

Screening for effective therapeutic agents from millions of drug candidates is costly, time consuming, and often faces concerns due to the extensive use of animals. To improve cost effectiveness, and to minimize animal testing in pharmaceutical research, in vitro monolayer cell microarrays with multiwell plate assays have been developed. Integration of cell microarrays with microfluidic systems has facilitated automated and controlled component loading, significantly reducing the consumption of the candidate compounds and the target cells. Even though these methods significantly increased the throughput compared to conventional in vitro testing systems and in vivo animal models, the cost associated with these platforms remains prohibitively high. Besides, there is a need for three-dimensional (3D) cell-based drug-screening models which can mimic the in vivo microenvironment and the functionality of the native tissues. Here, we present the state-of-the-art microengineering approaches that can be used to develop 3D cell-based drug-screening assays. We highlight the 3D in vitro cell culture systems with live cell-based arrays, microfluidic cell culture systems, and their application to high-throughput drug screening. We conclude that among the emerging microengineering approaches, bioprinting holds great potential to provide repeatable 3D cell-based constructs with high temporal, spatial control and versatility.

Microengineering methods for cell-based microarrays and high-throughput drug-screening applications

Energy Technology Data Exchange (ETDEWEB)

Xu Feng; Wu Jinhui; Wang Shuqi; Gurkan, Umut Atakan; Demirci, Utkan [Department of Medicine, Demirci Bio-Acoustic-MEMS in Medicine (BAMM) Laboratory, Center for Biomedical Engineering, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Durmus, Naside Gozde, E-mail: udemirci@rics.bwh.harvard.edu [School of Engineering and Division of Biology and Medicine, Brown University, Providence, RI (United States)

2011-09-15

Screening for effective therapeutic agents from millions of drug candidates is costly, time consuming, and often faces concerns due to the extensive use of animals. To improve cost effectiveness, and to minimize animal testing in pharmaceutical research, in vitro monolayer cell microarrays with multiwell plate assays have been developed. Integration of cell microarrays with microfluidic systems has facilitated automated and controlled component loading, significantly reducing the consumption of the candidate compounds and the target cells. Even though these methods significantly increased the throughput compared to conventional in vitro testing systems and in vivo animal models, the cost associated with these platforms remains prohibitively high. Besides, there is a need for three-dimensional (3D) cell-based drug-screening models which can mimic the in vivo microenvironment and the functionality of the native tissues. Here, we present the state-of-the-art microengineering approaches that can be used to develop 3D cell-based drug-screening assays. We highlight the 3D in vitro cell culture systems with live cell-based arrays, microfluidic cell culture systems, and their application to high-throughput drug screening. We conclude that among the emerging microengineering approaches, bioprinting holds great potential to provide repeatable 3D cell-based constructs with high temporal, spatial control and versatility.

Modelling of robotic work cells using agent based-approach

Science.gov (United States)

Sękala, A.; Banaś, W.; Gwiazda, A.; Monica, Z.; Kost, G.; Hryniewicz, P.

2016-08-01

In the case of modern manufacturing systems the requirements, both according the scope and according characteristics of technical procedures are dynamically changing. This results in production system organization inability to keep up with changes in a market demand. Accordingly, there is a need for new design methods, characterized, on the one hand with a high efficiency and on the other with the adequate level of the generated organizational solutions. One of the tools that could be used for this purpose is the concept of agent systems. These systems are the tools of artificial intelligence. They allow assigning to agents the proper domains of procedures and knowledge so that they represent in a self-organizing system of an agent environment, components of a real system. The agent-based system for modelling robotic work cell should be designed taking into consideration many limitations considered with the characteristic of this production unit. It is possible to distinguish some grouped of structural components that constitute such a system. This confirms the structural complexity of a work cell as a specific production system. So it is necessary to develop agents depicting various aspects of the work cell structure. The main groups of agents that are used to model a robotic work cell should at least include next pattern representatives: machine tool agents, auxiliary equipment agents, robots agents, transport equipment agents, organizational agents as well as data and knowledge bases agents. In this way it is possible to create the holarchy of the agent-based system.

Precise mass determination of single cell with cantilever-based microbiosensor system.

Directory of Open Access Journals (Sweden)

Bogdan Łabędź

Full Text Available Having determined the mass of a single cell of brewer yeast Saccharomyces cerevisiae by means of a microcantilever-based biosensor Cantisens CSR-801 (Concentris, Basel, Switzerland, it was found that its dry mass is 47,65 ± 1,05 pg. Found to be crucial in this mass determination was the cell position along the length of the cantilever. Moreover, calculations including cells positions on the cantilever provide a threefold better degree of accuracy than those which assume uniform mass distribution. We have also examined the influence of storage time on the single cell mass. Our results show that after 6 months there is an increase in the average mass of a single yeast cell.

Precise mass determination of single cell with cantilever-based microbiosensor system.

Science.gov (United States)

Łabędź, Bogdan; Wańczyk, Aleksandra; Rajfur, Zenon

2017-01-01

Having determined the mass of a single cell of brewer yeast Saccharomyces cerevisiae by means of a microcantilever-based biosensor Cantisens CSR-801 (Concentris, Basel, Switzerland), it was found that its dry mass is 47,65 ± 1,05 pg. Found to be crucial in this mass determination was the cell position along the length of the cantilever. Moreover, calculations including cells positions on the cantilever provide a threefold better degree of accuracy than those which assume uniform mass distribution. We have also examined the influence of storage time on the single cell mass. Our results show that after 6 months there is an increase in the average mass of a single yeast cell.

First experience with particle-in-cell plasma physics code on ARM-based HPC systems

OpenAIRE

Sáez, Xavier; Soba, Alejandro; Sánchez, Edilberto; Mantsinen, Mervi; Mateo, Sergio; Cela, José M.; Castejón, Francisco

2015-01-01

In this work, we will explore the feasibility of porting a Particle-in-cell code (EUTERPE) to an ARM multi-core platform from the Mont-Blanc project. The used prototype is based on a system-on-chip Samsung Exynos 5 with an integrated GPU. It is the first prototype that could be used for High-Performance Computing (HPC), since it supports double precision and parallel programming languages. The research leading to these results has received funding from the European Com- munity's Seventh...

The modeling and simulation of thermal based modified solid oxide fuel cell (SOFC for grid-connected systems

Directory of Open Access Journals (Sweden)

Ayetül Gelen

2015-05-01

Full Text Available This paper presents a thermal based modified dynamic model of a Solid Oxide Fuel Cell (SOFC for grid-connected systems. The proposed fuel cell model involves ohmic, activation and concentration voltage losses, thermal dynamics, methanol reformer, fuel utilization factor and power limiting module. A power conditioning unit (PCU, which consists of a DC-DC boost converter and a DC-AC voltage-source inverter (VSI, their controller, transformer and filter, is designed for grid-connected systems. The voltage-source inverter with six Insulated Gate Bipolar Transistor (IGBT switches inverts the DC voltage that comes from the converter into a sinusoidal voltage synchronized with the grid. The simulations and modeling of the system are developed on Matlab/Simulink environment. The performance of SOFC with converter is examined under step and random load conditions. The simulation results show that the designed boost converter for the proposed thermal based modified SOFC model has fairly followed different DC load variations. Finally, the AC bus of 400 Volt and 50 Hz is connected to a single-machine infinite bus (SMIB through a transmission line. The real and reactive power managements of the inverter are analyzed by an infinite bus system. Thus, the desired nominal values are properly obtained by means of the inverter controller.

Glucose-based Biofuel Cells: Nanotechnology as a Vital Science in Biofuel Cells Performance

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Hamideh Aghahosseini

2016-07-01

Full Text Available Nanotechnology has opened up new opportunities for the design of nanoscale electronic devices suitable for developing high-performance biofuel cells. Glucose-based biofuel cells as green energy sources can be a powerful tool in the service of small-scale power source technology as it provides a latent potential to supply power for various implantable medical electronic devices. By using physiologically produced glucose as a fuel, the living battery can recharge for continuous production of electricity. This review article presents how nanoscience, engineering and medicine are combined to assist in the development of renewable glucose-based biofuel cell systems. Here, we review recent advances and applications in both abiotic and enzymatic glucose biofuel cells with emphasis on their “implantable” and “implanted” types. Also the challenges facing the design and application of glucose-based biofuel cells to convert them to promising replacement candidates for non-rechargeable lithium-ion batteries are discussed. Nanotechnology could make glucose-based biofuel cells cheaper, lighter and more efficient and hence it can be a part of the solutions to these challenges.

Culture expansion of adipose derived stromal cells. A closed automated Quantum Cell Expansion System compared with manual flask-based culture

Directory of Open Access Journals (Sweden)

Mandana Haack-Sørensen

2016-11-01

Full Text Available Abstract Background Adipose derived stromal cells (ASCs are a rich and convenient source of cells for clinical regenerative therapeutic approaches. However, applications of ASCs often require cell expansion to reach the needed dose. In this study, cultivation of ASCs from stromal vascular fraction (SVF over two passages in the automated and functionally closed Quantum Cell Expansion System (Quantum system is compared with traditional manual cultivation. Methods Stromal vascular fraction was isolated from abdominal fat, suspended in α-MEM supplemented with 10% Fetal Bovine Serum and seeded into either T75 flasks or a Quantum system that had been coated with cryoprecipitate. The cultivation of ASCs from SVF was performed in 3 ways: flask to flask; flask to Quantum system; and Quantum system to Quantum system. In all cases, quality controls were conducted for sterility, mycoplasmas, and endotoxins, in addition to the assessment of cell counts, viability, immunophenotype, and differentiation potential. Results The viability of ASCs passage 0 (P0 and P1 was above 96%, regardless of cultivation in flasks or Quantum system. Expression of surface markers and differentiation potential was consistent with ISCT/IFATS standards for the ASC phenotype. Sterility, mycoplasma, and endotoxin tests were consistently negative. An average of 8.0 × 107 SVF cells loaded into a Quantum system yielded 8.96 × 107 ASCs P0, while 4.5 × 106 SVF cells seeded per T75 flask yielded an average of 2.37 × 106 ASCs—less than the number of SVF cells seeded. ASCs P1 expanded in the Quantum system demonstrated a population doubling (PD around 2.2 regardless of whether P0 was previously cultured in flasks or Quantum, while ASCs P1 in flasks only reached a PD of 1.0. Conclusion: Manufacturing of ASCs in a Quantum system enhances ASC expansion rate and yield significantly relative to manual processing in T-flasks, while maintaining the purity and quality essential to

Culture expansion of adipose derived stromal cells. A closed automated Quantum Cell Expansion System compared with manual flask-based culture.

Science.gov (United States)

Haack-Sørensen, Mandana; Follin, Bjarke; Juhl, Morten; Brorsen, Sonja K; Søndergaard, Rebekka H; Kastrup, Jens; Ekblond, Annette

2016-11-16

Adipose derived stromal cells (ASCs) are a rich and convenient source of cells for clinical regenerative therapeutic approaches. However, applications of ASCs often require cell expansion to reach the needed dose. In this study, cultivation of ASCs from stromal vascular fraction (SVF) over two passages in the automated and functionally closed Quantum Cell Expansion System (Quantum system) is compared with traditional manual cultivation. Stromal vascular fraction was isolated from abdominal fat, suspended in α-MEM supplemented with 10% Fetal Bovine Serum and seeded into either T75 flasks or a Quantum system that had been coated with cryoprecipitate. The cultivation of ASCs from SVF was performed in 3 ways: flask to flask; flask to Quantum system; and Quantum system to Quantum system. In all cases, quality controls were conducted for sterility, mycoplasmas, and endotoxins, in addition to the assessment of cell counts, viability, immunophenotype, and differentiation potential. The viability of ASCs passage 0 (P0) and P1 was above 96%, regardless of cultivation in flasks or Quantum system. Expression of surface markers and differentiation potential was consistent with ISCT/IFATS standards for the ASC phenotype. Sterility, mycoplasma, and endotoxin tests were consistently negative. An average of 8.0 × 10 7 SVF cells loaded into a Quantum system yielded 8.96 × 10 7 ASCs P0, while 4.5 × 10 6 SVF cells seeded per T75 flask yielded an average of 2.37 × 10 6 ASCs-less than the number of SVF cells seeded. ASCs P1 expanded in the Quantum system demonstrated a population doubling (PD) around 2.2 regardless of whether P0 was previously cultured in flasks or Quantum, while ASCs P1 in flasks only reached a PD of 1.0. Manufacturing of ASCs in a Quantum system enhances ASC expansion rate and yield significantly relative to manual processing in T-flasks, while maintaining the purity and quality essential to safe and robust cell production. Notably, the use of the Quantum

Machine Learning Based Single-Frame Super-Resolution Processing for Lensless Blood Cell Counting

Directory of Open Access Journals (Sweden)

Xiwei Huang

2016-11-01

Full Text Available A lensless blood cell counting system integrating microfluidic channel and a complementary metal oxide semiconductor (CMOS image sensor is a promising technique to miniaturize the conventional optical lens based imaging system for point-of-care testing (POCT. However, such a system has limited resolution, making it imperative to improve resolution from the system-level using super-resolution (SR processing. Yet, how to improve resolution towards better cell detection and recognition with low cost of processing resources and without degrading system throughput is still a challenge. In this article, two machine learning based single-frame SR processing types are proposed and compared for lensless blood cell counting, namely the Extreme Learning Machine based SR (ELMSR and Convolutional Neural Network based SR (CNNSR. Moreover, lensless blood cell counting prototypes using commercial CMOS image sensors and custom designed backside-illuminated CMOS image sensors are demonstrated with ELMSR and CNNSR. When one captured low-resolution lensless cell image is input, an improved high-resolution cell image will be output. The experimental results show that the cell resolution is improved by 4×, and CNNSR has 9.5% improvement over the ELMSR on resolution enhancing performance. The cell counting results also match well with a commercial flow cytometer. Such ELMSR and CNNSR therefore have the potential for efficient resolution improvement in lensless blood cell counting systems towards POCT applications.

Estimating cell capacity for multi-cell electrical energy system

Science.gov (United States)

Hashemi, Iman Ahari

A Multi-Cell Electrical Energy System is a set of batteries that are connected in series. The series batteries provide the required voltage necessary for the contraption. After using the energy that is provided by the batteries, some cells within the system tend to have a lower voltage than the other cells. Also, other factors, such as the number of times a battery has been charged or discharged, how long it has been within the system and many other factors, result in some cells having a lesser capacity compared to the other cells within the system. The outcome is that it lowers the required capacity that the electrical energy system is required to provide. By having an unknown cell capacity within the system, it is unknown how much of a charge can be provided to the system so that the cells are not overcharged or undercharged. Therefore, it is necessary to know the cells capacity within the system. Hence, if we were dealing with a single cell, the capacity could be obtained by a full charge and discharge of the cell. In a series system that contains multiple cells a full charging or discharging cannot happen as it might result in deteriorating the structure of some cells within the system. Hence, to find the capacity of a single cell within an electrical energy system it is required to obtain a method that can estimate the value of each cell within the electrical energy system. To approach this method an electrical energy system is required. The electrical energy system consists of rechargeable non-equal capacity batteries to provide the required energy to the system, a battery management system (BMS) board to monitor the cells voltages, an Arduino board that provides the required communication to BMS board, and the PC, and a software that is able to deliver the required data obtained from the Arduino board to the PC. The outcome, estimating the capacity of a cell within a multi-cell system, can be used in many battery related technologies to obtain unknown

Stem cell homing-based tissue engineering using bioactive materials

Science.gov (United States)

Yu, Yinxian; Sun, Binbin; Yi, Chengqing; Mo, Xiumei

2017-06-01

Tissue engineering focuses on repairing tissue and restoring tissue functions by employing three elements: scaffolds, cells and biochemical signals. In tissue engineering, bioactive material scaffolds have been used to cure tissue and organ defects with stem cell-based therapies being one of the best documented approaches. In the review, different biomaterials which are used in several methods to fabricate tissue engineering scaffolds were explained and show good properties (biocompatibility, biodegradability, and mechanical properties etc.) for cell migration and infiltration. Stem cell homing is a recruitment process for inducing the migration of the systemically transplanted cells, or host cells, to defect sites. The mechanisms and modes of stem cell homing-based tissue engineering can be divided into two types depending on the source of the stem cells: endogenous and exogenous. Exogenous stem cell-based bioactive scaffolds have the challenge of long-term culturing in vitro and for endogenous stem cells the biochemical signal homing recruitment mechanism is not clear yet. Although the stem cell homing-based bioactive scaffolds are attractive candidates for tissue defect therapies, based on in vitro studies and animal tests, there is still a long way before clinical application.

On the intrinsic transient capability and limitations of solid oxide fuel cell systems

OpenAIRE

Mueller, F; Jabbari, F; Brouwer, J

2009-01-01

The intrinsic transient performance capability and limitation of integrated solid oxide fuel cell (SOFC) systems is evaluated based on the system balance-of-plant response and fuel cell operating requirements (i.e., allowable deviation from nominal operation). Specifically, non-dimensional relations are derived from conservation principles that quantify the maximum instantaneous current increase that a solid oxide fuel cell system can safely manage based on (1) the desired fuel cell operating...

Universal low-temperature MWCNT-COOH-based counter electrode and a new thiolate/disulfide electrolyte system for dye-sensitized solar cells.

Science.gov (United States)

Hilmi, Abdulla; Shoker, Tharallah A; Ghaddar, Tarek H

2014-06-11

A new thiolate/disulfide organic-based electrolyte system composed of the tetrabutylammonium salt of 2-methyl-5-trifluoromethyl-2H-[1,2,4]triazole-3-thiol (S(-)) and its oxidized form 3,3'-dithiobis(2-methyl-5-trifluoromethyl-2H-[1,2,4]triazole) (DS) has been formulated and used in dye-sensitized solar cells (DSSCs). The electrocatalytic activity of different counter electrodes (CEs) has been evaluated by means of measuring J-V curves, cyclic voltammetry, Tafel plots, and electrochemical impedance spectroscopy. A stable and low-temperature CE based on acid-functionalized multiwalled carbon nanotubes (MWCNT-COOH) was investigated with our S(-)/DS, I(-)/I3(-), T(-)/T2, and Co(II/III)-based electrolyte systems. The proposed CE showed superb electrocatalytic activity toward the regeneration of the different electrolytes. In addition, good stability of solar cell devices based on the reported electrolyte and CE was shown.

Temperature dependent estimator for load cells using an adaptive neuro-fuzzy inference system

Energy Technology Data Exchange (ETDEWEB)

Lee, K-C [Department of Automation Engineering, National Formosa University, Huwei, Yunlin 63208, Taiwan (China)

2005-01-01

Accurate weighting of pieces in various temperature environments for load cells is a key feature in many industrial applications. This paper proposes a method to achieve high-precision {+-}0.56/3000 grams for a load-cell-based weighting system by using ANFIS. ANFIS is used to model the relationship between the reading of load cells and the actual weight of samples considering temperature-varying effect and nonlinearity of the load cells. The model of the load-cell-based weighting system can accurately estimate the weight of test samples from the load cell reading. The proposed ANFIS-based method is convenient for use and can improve the precision of digital load cell measurement systems. Experiments demonstrate the validity and effectiveness of fuzzy neural networks for modeling of load cells and the results show that the proposed ANFIS-based method outperforms some existing methods in terms of modeling and prediction accuracy.

Temperature dependent estimator for load cells using an adaptive neuro-fuzzy inference system

International Nuclear Information System (INIS)

Lee, K-C

2005-01-01

Accurate weighting of pieces in various temperature environments for load cells is a key feature in many industrial applications. This paper proposes a method to achieve high-precision ±0.56/3000 grams for a load-cell-based weighting system by using ANFIS. ANFIS is used to model the relationship between the reading of load cells and the actual weight of samples considering temperature-varying effect and nonlinearity of the load cells. The model of the load-cell-based weighting system can accurately estimate the weight of test samples from the load cell reading. The proposed ANFIS-based method is convenient for use and can improve the precision of digital load cell measurement systems. Experiments demonstrate the validity and effectiveness of fuzzy neural networks for modeling of load cells and the results show that the proposed ANFIS-based method outperforms some existing methods in terms of modeling and prediction accuracy

Fuzzy-based failure mode and effect analysis (FMEA) of a hybrid molten carbonate fuel cell (MCFC) and gas turbine system for marine propulsion

Science.gov (United States)

Ahn, Junkeon; Noh, Yeelyong; Park, Sung Ho; Choi, Byung Il; Chang, Daejun

2017-10-01

This study proposes a fuzzy-based FMEA (failure mode and effect analysis) for a hybrid molten carbonate fuel cell and gas turbine system for liquefied hydrogen tankers. An FMEA-based regulatory framework is adopted to analyze the non-conventional propulsion system and to understand the risk picture of the system. Since the participants of the FMEA rely on their subjective and qualitative experiences, the conventional FMEA used for identifying failures that affect system performance inevitably involves inherent uncertainties. A fuzzy-based FMEA is introduced to express such uncertainties appropriately and to provide flexible access to a risk picture for a new system using fuzzy modeling. The hybrid system has 35 components and has 70 potential failure modes, respectively. Significant failure modes occur in the fuel cell stack and rotary machine. The fuzzy risk priority number is used to validate the crisp risk priority number in the FMEA.

A CYP21A2 based whole-cell system in Escherichia coli for the biotechnological production of premedrol.

Science.gov (United States)

Brixius-Anderko, Simone; Schiffer, Lina; Hannemann, Frank; Janocha, Bernd; Bernhardt, Rita

2015-09-15

Synthetic glucocorticoids like methylprednisolone (medrol) are of high pharmaceutical interest and represent powerful drugs due to their anti-inflammatory and immunosuppressive effects. Since the chemical hydroxylation of carbon atom 21, a crucial step in the synthesis of the medrol precursor premedrol, exhibits a low overall yield because of a poor stereo- and regioselectivity, there is high interest in a more sustainable and efficient biocatalytic process. One promising candidate is the mammalian cytochrome P450 CYP21A2 which is involved in steroid hormone biosynthesis and performs a selective oxyfunctionalization of C21 to provide the precursors of aldosterone, the main mineralocorticoid, and cortisol, the most important glucocorticoid. In this work, we demonstrate the high potential of CYP21A2 for a biotechnological production of premedrol, an important precursor of medrol. We successfully developed a CYP21A2-based whole-cell system in Escherichia coli by coexpressing the cDNAs of bovine CYP21A2 and its redox partner, the NADPH-dependent cytochrome P450 reductase (CPR), via a bicistronic vector. The synthetic substrate medrane was selectively 21-hydroxylated to premedrol with a max. yield of 90 mg L(-1) d(-1). To further improve the biocatalytic activity of the system by a more effective electron supply, we exchanged the CPR with constructs containing five alternative redox systems. A comparison of the constructs revealed that the redox system with the highest endpoint yield converted 70 % of the substrate within the first 2 h showing a doubled initial reaction rate compared with the other constructs. Using the best system we could increase the overall yield of premedrol to a maximum of 320 mg L(-1) d(-1) in shaking flasks. Optimization of the biotransformation in a bioreactor could further improve the premedrol gain to a maximum of 0.65 g L(-1) d(-1). We successfully established a CYP21-based whole-cell system for the biotechnological production of premedrol

Improved biosensor-based detection system

DEFF Research Database (Denmark)

2015-01-01

Described is a new biosensor-based detection system for effector compounds, useful for in vivo applications in e.g. screening and selecting of cells which produce a small molecule effector compound or which take up a small molecule effector compound from its environment. The detection system...... comprises a protein or RNA-based biosensor for the effector compound which indirectly regulates the expression of a reporter gene via two hybrid proteins, providing for fewer false signals or less 'noise', tuning of sensitivity or other advantages over conventional systems where the biosensor directly...

Impute DC link (IDCL) cell based power converters and control thereof

Science.gov (United States)

Divan, Deepakraj M.; Prasai, Anish; Hernendez, Jorge; Moghe, Rohit; Iyer, Amrit; Kandula, Rajendra Prasad

2016-04-26

Power flow controllers based on Imputed DC Link (IDCL) cells are provided. The IDCL cell is a self-contained power electronic building block (PEBB). The IDCL cell may be stacked in series and parallel to achieve power flow control at higher voltage and current levels. Each IDCL cell may comprise a gate drive, a voltage sharing module, and a thermal management component in order to facilitate easy integration of the cell into a variety of applications. By providing direct AC conversion, the IDCL cell based AC/AC converters reduce device count, eliminate the use of electrolytic capacitors that have life and reliability issues, and improve system efficiency compared with similarly rated back-to-back inverter system.

Fluorogenic Cell-Based Biosensors for Monitoring Microbes

Science.gov (United States)

Curtis, Theresa; Salazar, Noe; Tabb, Joel; Chase, Chris

2010-01-01

Fluorogenic cell-based sensor systems for detecting microbes (especially pathogenic ones) and some toxins and allergens are undergoing development. These systems harness the natural signaltransduction and amplification cascades that occur in mast cells upon activation with antigens. These systems include (1) fluidic biochips for automated containment of samples, reagents, and wastes and (2) sensitive, compact fluorometers for monitoring the fluorescent responses of mast cells engineered to contain fluorescent dyes. It should be possible to observe responses within minutes of adding immune complexes. The systems have been shown to work when utilizing either immunoglobulin E (IgE) antibodies or traditionally generated rat antibodies - a promising result in that it indicates that the systems could be developed to detect many target microbes. Chimeric IgE antibodies and rat immunoglobulin G (IgG) antibodies could be genetically engineered for recognizing biological and chemical warfare agents and airborne and food-borne allergens. Genetic engineering efforts thus far have yielded (1) CD14 chimeric antibodies that recognize both Grampositive and Gram-negative bacteria and bind to the surfaces of mast cells, eliciting a degranulation response and (2) rat IgG2a antibodies that act similarly in response to low levels of canine parvovirus.

Voltage controlled nano-injection system for single-cell surgery

Science.gov (United States)

Seger, R. Adam; Actis, Paolo; Penfold, Catherine; Maalouf, Michelle; Vilozny, Boaz; Pourmand, Nader

2015-01-01

Manipulation and analysis of single cells is the next frontier in understanding processes that control the function and fate of cells. Herein we describe a single-cell injection platform based on nanopipettes. The system uses scanning microscopy techniques to detect cell surfaces, and voltage pulses to deliver molecules into individual cells. As a proof of concept, we injected adherent mammalian cells with fluorescent dyes. PMID:22899383

Characterisation of a fuel cell based uninteruptable power supply

Energy Technology Data Exchange (ETDEWEB)

Aklil, D.; Gazey, R.; McGrath, D.

2004-07-01

This report presents the findings of tests carried out to determine if a fuel cell (FC) could be used instead of external batteries in UPS systems. Details are given of the configuration of the 1kW fuel cell based test UPS system (FC-UPS), fuel cell suitability for UPS, the start-up conditions, the on-load dynamic response, comparative weight/space savings of FC-UPS, lifetime costs compared to battery installations, and market readiness of FC systems for UPS deployment. The importance of the collaboration between the FC manufacturers and system integrator for the implementation of the project and of the testing and characterisation of FC products is stressed.

Increasing cell-device adherence using cultured insect cells for receptor-based biosensors

Science.gov (United States)

Terutsuki, Daigo; Mitsuno, Hidefumi; Sakurai, Takeshi; Okamoto, Yuki; Tixier-Mita, Agnès; Toshiyoshi, Hiroshi; Mita, Yoshio; Kanzaki, Ryohei

2018-03-01

Field-effect transistor (FET)-based biosensors have a wide range of applications, and a bio-FET odorant sensor, based on insect (Sf21) cells expressing insect odorant receptors (ORs) with sensitivity and selectivity, has emerged. To fully realize the practical application of bio-FET odorant sensors, knowledge of the cell-device interface for efficient signal transfer, and a reliable and low-cost measurement system using the commercial complementary metal-oxide semiconductor (CMOS) foundry process, will be indispensable. However, the interfaces between Sf21 cells and sensor devices are largely unknown, and electrode materials used in the commercial CMOS foundry process are generally limited to aluminium, which is reportedly toxic to cells. In this study, we investigated Sf21 cell-device interfaces by developing cross-sectional specimens. Calcium imaging of Sf21 cells expressing insect ORs was used to verify the functions of Sf21 cells as odorant sensor elements on the electrode materials. We found that the cell-device interface was approximately 10 nm wide on average, suggesting that the adhesion mechanism of Sf21 cells may differ from that of other cells. These results will help to construct accurate signal detection from expressed insect ORs using FETs.

An insert-based enzymatic cell culture system to rapidly and reversibly induce hypoxia: investigations of hypoxia-induced cell damage, protein expression and phosphorylation in neuronal IMR-32 cells

Directory of Open Access Journals (Sweden)

Ying Huang

2013-11-01

Ischemia-reperfusion injury and tissue hypoxia are of high clinical relevance because they are associated with various pathophysiological conditions such as myocardial infarction and stroke. Nevertheless, the underlying mechanisms causing cell damage are still not fully understood, which is at least partially due to the lack of cell culture systems for the induction of rapid and transient hypoxic conditions. The aim of the study was to establish a model that is suitable for the investigation of cellular and molecular effects associated with transient and long-term hypoxia and to gain insights into hypoxia-mediated mechanisms employing a neuronal culture system. A semipermeable membrane insert system in combination with the hypoxia-inducing enzymes glucose oxidase and catalase was employed to rapidly and reversibly generate hypoxic conditions in the culture medium. Hydrogen peroxide assays, glucose measurements and western blotting were performed to validate the system and to evaluate the effects of the generated hypoxia on neuronal IMR-32 cells. Using the insert-based two-enzyme model, hypoxic conditions were rapidly induced in the culture medium. Glucose concentrations gradually decreased, whereas levels of hydrogen peroxide were not altered. Moreover, a rapid and reversible (onoff generation of hypoxia could be performed by the addition and subsequent removal of the enzyme-containing inserts. Employing neuronal IMR-32 cells, we showed that 3 hours of hypoxia led to morphological signs of cellular damage and significantly increased levels of lactate dehydrogenase (a biochemical marker of cell damage. Hypoxic conditions also increased the amounts of cellular procaspase-3 and catalase as well as phosphorylation of the pro-survival kinase Akt, but not Erk1/2 or STAT5. In summary, we present a novel framework for investigating hypoxia-mediated mechanisms at the cellular level. We claim that the model, the first of its kind, enables researchers to rapidly and

Machine learning-based methods for prediction of linear B-cell epitopes.

Science.gov (United States)

Wang, Hsin-Wei; Pai, Tun-Wen

2014-01-01

B-cell epitope prediction facilitates immunologists in designing peptide-based vaccine, diagnostic test, disease prevention, treatment, and antibody production. In comparison with T-cell epitope prediction, the performance of variable length B-cell epitope prediction is still yet to be satisfied. Fortunately, due to increasingly available verified epitope databases, bioinformaticians could adopt machine learning-based algorithms on all curated data to design an improved prediction tool for biomedical researchers. Here, we have reviewed related epitope prediction papers, especially those for linear B-cell epitope prediction. It should be noticed that a combination of selected propensity scales and statistics of epitope residues with machine learning-based tools formulated a general way for constructing linear B-cell epitope prediction systems. It is also observed from most of the comparison results that the kernel method of support vector machine (SVM) classifier outperformed other machine learning-based approaches. Hence, in this chapter, except reviewing recently published papers, we have introduced the fundamentals of B-cell epitope and SVM techniques. In addition, an example of linear B-cell prediction system based on physicochemical features and amino acid combinations is illustrated in details.

Process Intensification in Fuel Cell CHP Systems, the ReforCELL Project

Directory of Open Access Journals (Sweden)

José Luis Viviente

2016-10-01

Full Text Available This paper reports the findings of a FP7/FCH JU project (ReforCELL that developed materials (catalysts and membranes and an advance autothermal membrane reformer for a micro Combined Heat and Power (CHP system of 5 kWel based on a polymer electrolyte membrane fuel cell (PEMFC. In this project, an active, stable and selective catalyst was developed for the reactions of interest and its production was scaled up to kg scale (TRL5 (TRL: Technology Readiness Level. Simultaneously, new membranes for gas separation were developed. In particular, dense supported thin palladium-based membranes were developed for hydrogen separation from reactive mixtures. These membranes were successfully scaled up to TRL4 and used in lab-scale reactors for fluidized bed steam methane reforming (SMR and autothermal reforming (ATR and in a prototype reactor for ATR. Suitable sealing techniques able to integrate the different membranes in lab-scale and prototype reactors were also developed. The project also addressed the design and optimization of the subcomponents (BoP for the integration of the membrane reformer to the fuel cell system.

Stem Cell-Based Cell Carrier for Targeted Oncolytic Virotherapy: Translational Opportunity and Open Questions

Directory of Open Access Journals (Sweden)

Janice Kim

2015-11-01

Full Text Available Oncolytic virotherapy for cancer is an innovative therapeutic option where the ability of a virus to promote cell lysis is harnessed and reprogrammed to selectively destroy cancer cells. Such treatment modalities exhibited antitumor activity in preclinical and clinical settings and appear to be well tolerated when tested in clinical trials. However, the clinical success of oncolytic virotherapy has been significantly hampered due to the inability to target systematic metastasis. This is partly due to the inability of the therapeutic virus to survive in the patient circulation, in order to target tumors at distant sites. An early study from various laboratories demonstrated that cells infected with oncolytic virus can protect the therapeutic payload form the host immune system as well as function as factories for virus production and enhance the therapeutic efficacy of oncolytic virus. While a variety of cell lineages possessed potential as cell carriers, copious investigation has established stem cells as a very attractive cell carrier system in oncolytic virotherapy. The ideal cell carrier desire to be susceptible to viral infection as well as support viral infection, maintain immunosuppressive properties to shield the loaded viruses from the host immune system, and most importantly possess an intrinsic tumor homing ability to deliver loaded viruses directly to the site of the metastasis—all qualities stem cells exhibit. In this review, we summarize the recent work in the development of stem cell-based carrier for oncolytic virotherapy, discuss the advantages and disadvantages of a variety of cell carriers, especially focusing on why stem cells have emerged as the leading candidate, and finally propose a future direction for stem cell-based targeted oncolytic virotherapy that involves its establishment as a viable treatment option for cancer patients in the clinical setting.

A new method using insert-based systems (IBS) to improve cell behavior study on flexible and rigid biomaterials.

Science.gov (United States)

Grenade, Charlotte; Moniotte, Nicolas; Rompen, Eric; Vanheusden, Alain; Mainjot, Amélie; De Pauw-Gillet, Marie-Claire

2016-12-01

In vitro studies about biomaterials biological properties are essential screening tests. Yet cell cultures encounter difficulties related to cell retention on material surface or to the observation of both faces of permeable materials. The objective of the present study was to develop a reliable in vitro method to study cell behavior on rigid and flexible/permeable biomaterials elaborating two specific insert-based systems (IBS-R and IBS-F respectively). IBS-R was designed as a specific cylindrical polytetrafluoroethylene (PTFE) system to evaluate attachment, proliferation and morphology of human gingival fibroblasts (HGFs) on grade V titanium and lithium disilicate glass-ceramic discs characteristics of dental prostheses. The number of cells, their covering on discs and their morphology were determined from MTS assays and microscopic fluorescent images after 24, 48 and 72 h. IBS-F was developed as a two components system to study HGFs behavior on guided bone regeneration polyester membranes. The viability and the membrane barrier effect were evaluated by metabolic MTS assays and by scanning electron microscopy. IBS-R and IBS-F were shown to promote (1) easy and rapid handling; (2) cell retention on biomaterial surface; (3) accurate evaluation of the cellular proliferation, spreading and viability; (4) use of non-toxic material. Moreover IBS-F allowed the study of the cell migration through degradable membranes, with an access to both faces of the biomaterial and to the bottom of culture wells for medium changing.

Mass spectrometry-based proteomic exploration of the human immune system: focus on the inflammasome, global protein secretion, and T cells.

Science.gov (United States)

Nyman, Tuula A; Lorey, Martina B; Cypryk, Wojciech; Matikainen, Sampsa

2017-05-01

The immune system is our defense system against microbial infections and tissue injury, and understanding how it works in detail is essential for developing drugs for different diseases. Mass spectrometry-based proteomics can provide in-depth information on the molecular mechanisms involved in immune responses. Areas covered: Summarized are the key immunology findings obtained with MS-based proteomics in the past five years, with a focus on inflammasome activation, global protein secretion, mucosal immunology, immunopeptidome and T cells. Special focus is on extracellular vesicle-mediated protein secretion and its role in immune responses. Expert commentary: Proteomics is an essential part of modern omics-scale immunology research. To date, MS-based proteomics has been used in immunology to study protein expression levels, their subcellular localization, secretion, post-translational modifications, and interactions in immune cells upon activation by different stimuli. These studies have made major contributions to understanding the molecular mechanisms involved in innate and adaptive immune responses. New developments in proteomics offer constantly novel possibilities for exploring the immune system. Examples of these techniques include mass cytometry and different MS-based imaging approaches which can be widely used in immunology.

System Identification of a Non-Uniformly Sampled Multi-Rate System in Aluminium Electrolysis Cells

Directory of Open Access Journals (Sweden)

Håkon Viumdal

2014-07-01

Full Text Available Standard system identification algorithms are usually designed to generate mathematical models with equidistant sampling instants, that are equal for both input variables and output variables. Unfortunately, real industrial data sets are often disrupted by missing samples, variations of sampling rates in the different variables (also known as multi-rate systems, and intermittent measurements. In industries with varying events based maintenance or manual operational measures, intermittent measurements are performed leading to uneven sampling rates. Such is the case with aluminium smelters, where in addition the materials fed into the cell create even more irregularity in sampling. Both measurements and feeding are mostly manually controlled. A simplified simulation of the metal level in an aluminium electrolysis cell is performed based on mass balance considerations. System identification methods based on Prediction Error Methods (PEM such as Ordinary Least Squares (OLS, and the sub-space method combined Deterministic and Stochastic system identification and Realization (DSR, and its variants are applied to the model of a single electrolysis cell as found in the aluminium smelters. Aliasing phenomena due to large sampling intervals can be crucial in avoiding unsuitable models, but with knowledge about the system dynamics, it is easier to optimize the sampling performance, and hence achieve successful models. The results based on the simulation studies of molten aluminium height in the cells using the various algorithms give results which tally well with the synthetic data sets used. System identification on a smaller data set from a real plant is also implemented in this work. Finally, some concrete suggestions are made for using these models in the smelters.

In-cell protease assay systems based on trans-localizing molecular beacon proteins using HCV protease as a model system.

Directory of Open Access Journals (Sweden)

Jeong Hee Kim

Full Text Available This study describes a sensitive in-cell protease detection system that enables direct fluorescence detection of a target protease and its inhibition inside living cells. This live-cell imaging system provides a fluorescent molecular beacon protein comprised of an intracellular translocation signal sequence, a protease-specific cleavage sequence, and a fluorescent tag sequence(s. The molecular beacon protein is designed to change its intracellular localization upon cleavage by a target protease, i.e., from the cytosol to a subcellular organelle or from a subcellular organelle to the cytosol. Protease activity can be monitored at the single cell level, and accordingly the entire cell population expressing the protease can be accurately enumerated. The clear cellular change in fluorescence pattern makes this system an ideal tool for various life science and drug discovery research, including high throughput and high content screening applications.

Theoretical Analysis of Two Novel Hybrid Thermoelectric-Photovoltaic Systems Based on Cu₂ZnSnS₄ Solar Cells.

Science.gov (United States)

Lorenzi, Bruno; Contento, Gaetano; Sabatelli, Vincenzo; Rizzo, Antonella; Narducci, Dario

2017-03-01

The development and commercialization of Photovoltaic (PV) cells with good cost-efficiency trade-off not using critical raw materials (CRMs) is one of the strategies chosen by the European Community (EC) to address the Energy Roadmap 2050. In this context Cu2ZnSnS4 (CZTS) solar cells are attracting a major interest since they have the potential to combine low price with relatively high conversion efficiencies. Although a ≈9% lab scale efficiency has already been reported for CZTS this technology is still far from being competitive in terms of cost per peak-power (€/Wp) with other common materials. One possible near-future solution to increase the CZTS competiveness comes from thermoelectrics. Actually it has already been shown that Hybrid Thermoelectric-Photovoltaic Systems (HTEPVs) based on CIGS, another kesterite very similar to CZTS, can lead to a significant efficiency improvement. However it has been also clarified how the optimal hybridization strategy cannot come from the simple coupling of solar cells with commercial TEGs, but special layouts have to be implemented. Furthermore, since solar cell performances are well known to decrease with temperature, thermal decoupling strategies of the PV and TEG sections have to be taken. To address these issues, we developed a model for two different HTEPV solutions, both coupled with CZTS solar cells. In the first case we considered a Thermally-Coupled HTEPV device (TC-HTEPV) in which the TEG is placed underneath the solar cell and in thermal contact with it. The second system consists instead of an Optically-Coupled but thermally decoupled device (OC-HTEPV) in which part of the solar spectrum is focused by a non-imaging optical concentrator on the TEG hot side. For both solutions the model returns conversion efficiencies higher than that of the CZTS solar cell alone. Specifically, increases of ≈30% are predicted for both kind of systems considered.

Direct methanol feed fuel cell and system

Science.gov (United States)

Surampudi, Subbarao (Inventor); Frank, Harvey A. (Inventor); Narayanan, Sekharipuram R. (Inventor); Chun, William (Inventor); Jeffries-Nakamura, Barbara (Inventor); Kindler, Andrew (Inventor); Halpert, Gerald (Inventor)

2009-01-01

Improvements to non acid methanol fuel cells include new formulations for materials. The platinum and ruthenium are more exactly mixed together. Different materials are substituted for these materials. The backing material for the fuel cell electrode is specially treated to improve its characteristics. A special sputtered electrode is formed which is extremely porous. The fuel cell system also comprises a fuel supplying part including a meter which meters an amount of fuel which is used by the fuel cell, and controls the supply of fuel based on said metering.

Hybrid fuel cell/diesel generation total energy system, part 2

Science.gov (United States)

Blazek, C. F.

1982-11-01

Meeting the Goldstone Deep Space Communications Complex (DGSCC) electrical and thermal requirements with the existing system was compared with using fuel cells. Fuel cell technology selection was based on a 1985 time frame for installation. The most cost-effective fuel feedstock for fuel cell application was identified. Fuels considered included diesel oil, natural gas, methanol and coal. These fuel feedstocks were considered not only on the cost and efficiency of the fuel conversion process, but also on complexity and integration of the fuel processor on system operation and thermal energy availability. After a review of fuel processor technology, catalytic steam reformer technology was selected based on the ease of integration and the economics of hydrogen production. The phosphoric acid fuel cell was selected for application at the GDSCC due to its commercial readiness for near term application. Fuel cell systems were analyzed for both natural gas and methanol feedstock. The subsequent economic analysis indicated that a natural gas fueled system was the most cost effective of the cases analyzed.

Reserve, thin form-factor, hypochlorite-based cells for powering portable systems: Manufacture (including MEMS processes), performance and characterization

Energy Technology Data Exchange (ETDEWEB)

Cardenas-Valencia, Andres M.; Langebrake, Larry [Center for Ocean Technology, University of South Florida, 140 Seventh Ave. S., St. Petersburg, FL (United States); Biver, Carl J. [Center for Ocean Technology, University of South Florida, 140 Seventh Ave. S., St. Petersburg, FL (United States); Department of Chemical Engineering, University of South Florida, 4202 E. Fowler Ave. Tampa, FL (United States)

2007-03-30

This work focuses on fabrication routes and performance evaluation of thin form-factors, reserve cells, as a powering alternative for expendable and/or remotely operated systems. The catalytic decomposition of sodium hypochlorite solutions is revisited herein with two cost-effective anodes: zinc and aluminum. Aluminum, even though the most expensive of the utilized anodes, constituted cells with double the energy content (up to 55 Wh kg{sup -1}) than those fabricated with zinc. Even though the hypochlorite concentration in the solution limits the cells' operational life, attractive performances (1.0 V with a current of 10 mA) for the manufactured cells are obtained. It is shown that micro fabrication processes, allowing for close electrodes interspacing, provided high faradic and columbic efficiencies of up to 70 and 100%, respectively. Obtained specific energies (50-120 Wh kg{sup -1}) are in the same order of magnitude than batteries currently used for powering deployable systems. Experimental results show that a simple model that linearly relates over potentials and the electrical load, adequately describe all the cell designs. A mathematical model based on a kinetic-mechanistic scheme that relates the current output as a function of time agrees fairly well with results obtained activating cells with various concentrations of NaOCl solutions. (author)

Solid Oxide Fuel Cell Systems PVL Line

International Nuclear Information System (INIS)

Shearer, Susan; Rush, Gregory

2012-01-01

In July 2010, Stark State College (SSC), received Grant DE-EE0003229 from the U.S. Department of Energy (DOE), Golden Field Office, for the development of the electrical and control systems, and mechanical commissioning of a unique 20kW scale high-pressure, high temperature, natural gas fueled Stack Block Test System (SBTS). SSC worked closely with subcontractor, Rolls-Royce Fuel Cell Systems (US) Inc. (RRFCS) over a 13 month period to successfully complete the project activities. This system will be utilized by RRFCS for pre-commercial technology development and training of SSC student interns. In the longer term, when RRFCS is producing commercial products, SSC will utilize the equipment for workforce training. In addition to DOE Hydrogen, Fuel Cells, and Infrastructure Technologies program funding, RRFCS internal funds, funds from the state of Ohio, and funding from the DOE Solid State Energy Conversion Alliance (SECA) program have been utilized to design, develop and commission this equipment. Construction of the SBTS (mechanical components) was performed under a Grant from the State of Ohio through Ohio's Third Frontier program (Grant TECH 08-053). This Ohio program supported development of a system that uses natural gas as a fuel. Funding was provided under the Department of Energy (DOE) Solid-state Energy Conversion Alliance (SECA) program for modifications required to test on coal synthesis gas. The subject DOE program provided funding for the electrical build, control system development and mechanical commissioning. Performance testing, which includes electrical commissioning, was subsequently performed under the DOE SECA program. Rolls-Royce Fuel Cell Systems is developing a megawatt-scale solid oxide fuel cell (SOFC) stationary power generation system. This system, based on RRFCS proprietary technology, is fueled with natural gas, and operates at elevated pressure. A critical success factor for development of the full scale system is the capability to

Fuzzy Logic Based Control of Power of PEM Fuel Cell System for Residential Application

Directory of Open Access Journals (Sweden)

Khaled MAMMAR

2009-07-01

Full Text Available This paper presents a dynamic model of Fuel cell system for residential power generation. The models proposed include a fuel cell stack model, reformer model and DC/AC inverter model. Furthermore a fuzzy logic (FLC controller is used to control active power of PEM fuel cell system. The controller modifies the hydrogen flow feedback from the terminal load. Simulation results confirmed the high performance capability of the fuzzy logic controller to control power generation.

A novel proton exchange membrane fuel cell based power conversion system for telecom supply with genetic algorithm assisted intelligent interfacing converter

International Nuclear Information System (INIS)

Kaur, Rajvir; Krishnasamy, Vijayakumar; Muthusamy, Kaleeswari; Chinnamuthan, Periasamy

2017-01-01

Highlights: • Proton exchange membrane fuel cell based telecom tower supply is proposed. • The use of diesel generator is eliminated and battery size is reduced. • Boost converter based intelligent interfacing unit is implemented. • The genetic algorithm assisted controller is proposed for effective interfacing. • The controller is robust against input and output disturbance rejection. - Abstract: This paper presents the fuel cell based simple electric energy conversion system for supplying the telecommunication towers to reduce the operation and maintenance cost of telecom companies. The telecom industry is at the boom and is penetrating deep into remote rural areas having unreliable or no grid supply. The telecom industry is getting heavily dependent on a diesel generator set and battery bank as a backup for continuously supplying a base transceiver station of telecom towers. This excessive usage of backup supply resulted in increased operational expenditure, the unreliability of power supply and had become a threat to the environment. A significant development and concern of clean energy sources, proton exchange membrane fuel cell based supply for base transceiver station is proposed with intelligent interfacing unit. The necessity of the battery bank capacity is significantly reduced as compared with the earlier solutions. Further, a simple closed loop and genetic algorithm assisted controller is proposed for intelligent interfacing unit which consists of power electronic boost converter for power conditioning. The proposed genetic algorithm assisted controller would ensure the tight voltage regulation at the DC distribution bus of the base transceiver station. Also, it will provide the robust performance of the base transceiver station under telecom load variation and proton exchange membrane fuel cell output voltage fluctuations. The complete electric energy conversion system along with telecom loads is simulated in MATLAB/Simulink platform and

A cell-based model system links chromothripsis with hyperploidy

DEFF Research Database (Denmark)

Mardin, Balca R; Drainas, Alexandros P; Waszak, Sebastian M

2015-01-01

A remarkable observation emerging from recent cancer genome analyses is the identification of chromothripsis as a one-off genomic catastrophe, resulting in massive somatic DNA structural rearrangements (SRs). Largely due to lack of suitable model systems, the mechanistic basis of chromothripsis h...... in hyperploid cells. Analysis of primary medulloblastoma cancer genomes verified the link between hyperploidy and chromothripsis in vivo. CAST provides the foundation for mechanistic dissection of complex DNA rearrangement processes....

Organic electrochemical transistors for cell-based impedance sensing

International Nuclear Information System (INIS)

Rivnay, Jonathan; Ramuz, Marc; Hama, Adel; Huerta, Miriam; Owens, Roisin M.; Leleux, Pierre

2015-01-01

Electrical impedance sensing of biological systems, especially cultured epithelial cell layers, is now a common technique to monitor cell motion, morphology, and cell layer/tissue integrity for high throughput toxicology screening. Existing methods to measure electrical impedance most often rely on a two electrode configuration, where low frequency signals are challenging to obtain for small devices and for tissues with high resistance, due to low current. Organic electrochemical transistors (OECTs) are conducting polymer-based devices, which have been shown to efficiently transduce and amplify low-level ionic fluxes in biological systems into electronic output signals. In this work, we combine OECT-based drain current measurements with simultaneous measurement of more traditional impedance sensing using the gate current to produce complex impedance traces, which show low error at both low and high frequencies. We apply this technique in vitro to a model epithelial tissue layer and show that the data can be fit to an equivalent circuit model yielding trans-epithelial resistance and cell layer capacitance values in agreement with literature. Importantly, the combined measurement allows for low biases across the cell layer, while still maintaining good broadband signal

MEMS-based platforms for mechanical manipulation and characterization of cells

Science.gov (United States)

Pan, Peng; Wang, Wenhui; Ru, Changhai; Sun, Yu; Liu, Xinyu

2017-12-01

Mechanical manipulation and characterization of single cells are important experimental techniques in biological and medical research. Because of the microscale sizes and highly fragile structures of cells, conventional cell manipulation and characterization techniques are not accurate and/or efficient enough or even cannot meet the more and more demanding needs in different types of cell-based studies. To this end, novel microelectromechanical systems (MEMS)-based technologies have been developed to improve the accuracy, efficiency, and consistency of various cell manipulation and characterization tasks, and enable new types of cell research. This article summarizes existing MEMS-based platforms developed for cell mechanical manipulation and characterization, highlights their specific design considerations making them suitable for their designated tasks, and discuss their advantages and limitations. In closing, an outlook into future trends is also provided.

Integrating fuel cell power systems into building physical plants

Energy Technology Data Exchange (ETDEWEB)

Carson, J. [KCI Technologies, Inc., Hunt Valley, MD (United States)

1996-12-31

This paper discusses the integration of fuel cell power plants and absorption chillers to cogenerate chilled water or hot water/steam for all weather air conditioning as one possible approach to building system applications. Absorption chillers utilize thermal energy in an absorption based cycle to chill water. It is feasible to use waste heat from fuel cells to provide hydronic heating and cooling. Performance regimes will vary as a function of the supply and quality of waste heat. Respective performance characteristics of fuel cells, absorption chillers and air conditioning systems will define relationships between thermal and electrical load capacities for the combined systems. Specifically, this paper develops thermodynamic relationships between bulk electrical power and cooling/heating capacities for combined fuel cell and absorption chiller system in building applications.

Atomic Force Microscopy Based Cell Shape Index

Science.gov (United States)

Adia-Nimuwa, Usienemfon; Mujdat Tiryaki, Volkan; Hartz, Steven; Xie, Kan; Ayres, Virginia

2013-03-01

Stellation is a measure of cell physiology and pathology for several cell groups including neural, liver and pancreatic cells. In the present work, we compare the results of a conventional two-dimensional shape index study of both atomic force microscopy (AFM) and fluorescent microscopy images with the results obtained using a new three-dimensional AFM-based shape index similar to sphericity index. The stellation of astrocytes is investigated on nanofibrillar scaffolds composed of electrospun polyamide nanofibers that has demonstrated promise for central nervous system (CNS) repair. Recent work by our group has given us the ability to clearly segment the cells from nanofibrillar scaffolds in AFM images. The clear-featured AFM images indicated that the astrocyte processes were longer than previously identified at 24h. It was furthermore shown that cell spreading could vary significantly as a function of environmental parameters, and that AFM images could record these variations. The new three-dimensional AFM-based shape index incorporates the new information: longer stellate processes and cell spreading. The support of NSF PHY-095776 is acknowledged.

Tri-generation System based on Municipal Waste Gasification, Fuel Cell and an Absorption Chiller

Directory of Open Access Journals (Sweden)

Giannis Katsaros

2018-03-01

Full Text Available The present work focuses on the design of a novel tri-generation system based on gasification of municipal solid wastes, a solid oxide fuel cell and an ammonia-water absorption chiller. Tri-generation systems can be implemented in buildings such as hospitals and hotels, where there is a continuous and large demand for electricity, heating and cooling. The system is modelled in Aspen Plus and the influence of different operating parameters on the system performance was studied. The findings suggest that low air equivalent ratios and high gasification temperatures enhance the overall system performance. Syngas cleaning with metal sorbents zinc oxide and sodium bicarbonate for the removal of hydrogen sulfide and hydrogen chloride concentrations proved to be very effective, reducing the concentration of contaminants to < 1 ppm (part per million levels. The possibility of covering the demand profiles of a specific building was also investigated: the system could fully meet the electricity and cooling demands, whereas the heat requirements could be satisfied only up to 55%. Moreover, assuming 20 years of operation, the payback period was 4.5 years and the net present value exceeded 5 million euros.

A hybrid agent-based approach for modeling microbiological systems.

Science.gov (United States)

Guo, Zaiyi; Sloot, Peter M A; Tay, Joc Cing

2008-11-21

Models for systems biology commonly adopt Differential Equations or Agent-Based modeling approaches for simulating the processes as a whole. Models based on differential equations presuppose phenomenological intracellular behavioral mechanisms, while models based on Multi-Agent approach often use directly translated, and quantitatively less precise if-then logical rule constructs. We propose an extendible systems model based on a hybrid agent-based approach where biological cells are modeled as individuals (agents) while molecules are represented by quantities. This hybridization in entity representation entails a combined modeling strategy with agent-based behavioral rules and differential equations, thereby balancing the requirements of extendible model granularity with computational tractability. We demonstrate the efficacy of this approach with models of chemotaxis involving an assay of 10(3) cells and 1.2x10(6) molecules. The model produces cell migration patterns that are comparable to laboratory observations.

Thermal Design for Extra-Terrestrial Regenerative Fuel Cell System

Science.gov (United States)

Gilligan, R.; Guzik, M.; Jakupca, I.; Bennett, W.; Smith, P.; Fincannon, J.

2017-01-01

The Advanced Exploration Systems (AES) Advanced Modular Power Systems (AMPS) Project is investigating different power systems for various lunar and Martian mission concepts. The AMPS Fuel Cell (FC) team has created two system-level models to evaluate the performance of regenerative fuel cell (RFC) systems employing different fuel cell chemistries. Proton Exchange Membrane fuel cells PEMFCs contain a polymer electrolyte membrane that separates the hydrogen and oxygen cavities and conducts hydrogen cations (protons) across the cell. Solid Oxide fuel cells (SOFCs) operate at high temperatures, using a zirconia-based solid ceramic electrolyte to conduct oxygen anions across the cell. The purpose of the modeling effort is to down select one fuel cell chemistry for a more detailed design effort. Figures of merit include the system mass, volume, round trip efficiency, and electrolyzer charge power required. PEMFCs operate at around 60 C versus SOFCs which operate at temperatures greater than 700 C. Due to the drastically different operating temperatures of the two chemistries the thermal control systems (TCS) differ. The PEM TCS is less complex and is characterized by a single pump cooling loop that uses deionized water coolant and rejects heat generated by the system to the environment via a radiator. The solid oxide TCS has its own unique challenges including the requirement to reject high quality heat and to condense the steam produced in the reaction. This paper discusses the modeling of thermal control systems for an extraterrestrial RFC that utilizes either a PEM or solid oxide fuel cell.

Phenotype-Based Screening of Small Molecules to Modify Plant Cell Walls Using BY-2 Cells.

Science.gov (United States)

Okubo-Kurihara, Emiko; Matsui, Minami

2018-01-01

The plant cell wall is an important and abundant biomass with great potential for use as a modern recyclable resource. For effective utilization of this cellulosic biomass, its ability to degrade efficiently is key point. With the aim of modifying the cell wall to allow easy decomposition, we used chemical biological technology to alter its structure. As a first step toward evaluating the chemicals in the cell wall we employed a phenotype-based approach using high-throughput screening. As the plant cell wall is essential in determining cell morphology, phenotype-based screening is particularly effective in identifying compounds that bring about alterations in the cell wall. For rapid and reproducible screening, tobacco BY-2 cell is an excellent system in which to observe cell morphology. In this chapter, we provide a detailed chemical biological methodology for studying cell morphology using tobacco BY-2 cells.

Baicalein induces cell death in murine T cell lymphoma via inhibition of thioredoxin system.

Science.gov (United States)

Patwardhan, Raghavendra S; Pal, Debojyoti; Checker, Rahul; Sharma, Deepak; Sandur, Santosh K

2017-10-01

We have earlier demonstrated the radioprotective potential of baicalein using murine splenic lymphocytes. Here, we have studied the effect of baicalein on murine T cell lymphoma EL4 cells and investigated the underlying mechanism of action. We observed that baicalein induced a dose dependent cell death in EL4 cells in vitro and significantly reduced the frequency of cancer stem cells. Previously, we have reported that murine and human T cell lymphoma cells have increased oxidative stress tolerance capacity due to active thioredoxin system. Hence, we monitored the effect of baicalein on thioredoxin system in EL4 cells. Docking studies revealed that baicalein could bind to the active site of thioredoxin reductase. Baicalein treatment led to significant reduction in the activity of thioredoxin reductase and nuclear levels of thioredoxin-1 thereby increasing ASK1 levels and caspase-3 activity. Interestingly, CRISPR-Cas9 based knock-out of ASK1 or over-expression of thioredoxin-1 abolished anti-tumor effects of baicalein in EL4 cells. Further, baicalein administration significantly reduced intra-peritoneal tumor burden of EL4 cells in C57BL/6 mice. Thus, our study describes anti-tumor effects of baicalein in EL4 cells via inhibition of thioredoxin system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Natural killer (NK) cells inhibit systemic metastasis of glioblastoma cells and have therapeutic effects against glioblastomas in the brain.

Science.gov (United States)

Lee, Se Jeong; Kang, Won Young; Yoon, Yeup; Jin, Ju Youn; Song, Hye Jin; Her, Jung Hyun; Kang, Sang Mi; Hwang, Yu Kyeong; Kang, Kyeong Jin; Joo, Kyeung Min; Nam, Do-Hyun

2015-12-24

Glioblastoma multiforme (GBM) is characterized by extensive local invasion, which is in contrast with extremely rare systemic metastasis of GBM. Molecular mechanisms inhibiting systemic metastasis of GBM would be a novel therapeutic candidate for GBM in the brain. Patient-derived GBM cells were primarily cultured from surgical samples of GBM patients and were inoculated into the brains of immune deficient BALB/c-nude or NOD-SCID IL2Rgamma(null) (NSG) mice. Human NK cells were isolated from peripheral blood mononucleated cells and expanded in vitro. Patient-derived GBM cells in the brains of NSG mice unexpectedly induced spontaneous lung metastasis although no metastasis was detected in BALB/c-nude mice. Based on the difference of the innate immunity between two mouse strains, NK cell activities of orthotopic GBM xenograft models based on BALB/c-nude mice were inhibited. NK cell inactivation induced spontaneous lung metastasis of GBM cells, which indicated that NK cells inhibit the systemic metastasis. In vitro cytotoxic activities of human NK cells against GBM cells indicated that cytotoxic activity of NK cells against GBM cells prevents systemic metastasis of GBM and that NK cells could be effective cell therapeutics against GBM. Accordingly, NK cells transplanted into orthotopic GBM xenograft models intravenously or intratumorally induced apoptosis of GBM cells in the brain and showed significant therapeutic effects. Our results suggest that innate NK immunity is responsible for rare systemic metastasis of GBM and that sufficient supplementation of NK cells could be a promising immunotherapeutic strategy for GBM in the brain.

Evaluation of an alkaline fuel cell system as a micro-CHP

International Nuclear Information System (INIS)

Verhaert, Ivan; Mulder, Grietus; De Paepe, Michel

2016-01-01

Highlights: • Sensitivity analysis on system configuration of the AFC as a micro-CHP. • Flow rate in the secondary heating circuit can be used to control water management. • Part load behavior of fuel cells is compared to other micro-CHP technologies. • For future energy demand in buildings fuel cells have the best performance. - Abstract: Micro-cogeneration is an emerging technology to reduce the non-renewable energy demand in buildings and reduce peak load in the grid. Fuel cell based cogeneration (CHP) has interesting prospects for building applications, even at relatively low heat demand. This is due to their partial load behavior which is completely different, compared to other micro-CHP technologies. Within the fuel cell technologies suitable for small scale CHP or micro-CHP, the existing configuration of an alkaline fuel cell system is analyzed. This analysis is based on validated models and offers a control strategy to optimize both water management and energy performance of the alkaline fuel cell system. Finally, the model of the alkaline fuel cell system with optimized control strategy is used to compare its part load behavior to other micro-CHP technologies.

Gas composition modeling in a reformed Methanol Fuel Cell system using adaptive Neuro-Fuzzy Inference Systems

DEFF Research Database (Denmark)

Justesen, Kristian Kjær; Andreasen, Søren Juhl; Shaker, Hamid Reza

2013-01-01

This work presents a method for modeling the gas composition in a Reformed Methanol Fuel Cell system. The method is based on Adaptive Neuro-Fuzzy-Inference-Systems which are trained on experimental data. The developed models are of the H2, CO2, CO and CH3OH mass flows of the reformed gas. The ANFIS......, or fuel cell diagnostics systems....

Well-Controlled Cell-Trapping Systems for Investigating Heterogeneous Cell-Cell Interactions.

Science.gov (United States)

Kamiya, Koki; Abe, Yuta; Inoue, Kosuke; Osaki, Toshihisa; Kawano, Ryuji; Miki, Norihisa; Takeuchi, Shoji

2018-03-01

Microfluidic systems have been developed for patterning single cells to study cell-cell interactions. However, patterning multiple types of cells to understand heterogeneous cell-cell interactions remains difficult. Here, it is aimed to develop a cell-trapping device to assemble multiple types of cells in the well-controlled order and morphology. This device mainly comprises a parylene sheet for assembling cells and a microcomb for controlling the cell-trapping area. The cell-trapping area is controlled by moving the parylene sheet on an SU-8 microcomb using tweezers. Gentle downward flow is used as a driving force for the cell-trapping. The assembly of cells on a parylene sheet with round and line-shaped apertures is demonstrated. The cell-cell contacts of the trapped cells are then investigated by direct cell-cell transfer of calcein via connexin nanopores. Finally, using the device with a system for controlling the cell-trapping area, three different types of cells in the well-controlled order are assembled. The correct cell order rate obtained using the device is 27.9%, which is higher than that obtained without the sliding parylene system (0.74%). Furthermore, the occurrence of cell-cell contact between the three cell types assembled is verified. This cell-patterning device will be a useful tool for investigating heterogeneous cell-cell interactions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Neural-Network-Based Approach to White Blood Cell Classification

Directory of Open Access Journals (Sweden)

Mu-Chun Su

2014-01-01

Full Text Available This paper presents a new white blood cell classification system for the recognition of five types of white blood cells. We propose a new segmentation algorithm for the segmentation of white blood cells from smear images. The core idea of the proposed segmentation algorithm is to find a discriminating region of white blood cells on the HSI color space. Pixels with color lying in the discriminating region described by an ellipsoidal region will be regarded as the nucleus and granule of cytoplasm of a white blood cell. Then, through a further morphological process, we can segment a white blood cell from a smear image. Three kinds of features (i.e., geometrical features, color features, and LDP-based texture features are extracted from the segmented cell. These features are fed into three different kinds of neural networks to recognize the types of the white blood cells. To test the effectiveness of the proposed white blood cell classification system, a total of 450 white blood cells images were used. The highest overall correct recognition rate could reach 99.11% correct. Simulation results showed that the proposed white blood cell classification system was very competitive to some existing systems.

Polybenzimidazoles based on high temperature polymer electrolyte fuel cells

Energy Technology Data Exchange (ETDEWEB)

Linares Leon, Jose Joaquin; Camargo, Ana Paula M.; Ashino, Natalia M.; Morgado, Daniella L.; Frollini, Elisabeth; Paganin, Valdecir A.; Gonzalez, Ernesto Rafael [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil); Bajo, Justo Lobato [University of Castilla-La Mancha, Ciudad Real (Spain). Dept. of Chemical Engineering

2010-07-01

This work presents an interesting approach in order to enhance the performance of Polymer Electrolyte Membrane Fuel Cells (PEMFC) by means of an increase in the operational temperature. For this, two polymeric materials, Poly(2,5-bibenzimidazole) (ABPBI) and Poly[2,2'-(m-phenyl en)-5,5' bib enzimidazol] (PBI), impregnated with phosphoric acid have been utilized. These have shown excellent properties, such as thermal stability above 500 deg C, reasonably high conductivity when impregnated with H{sub 3}PO{sub 4} and a low permeability to alcohols compared to Nafion. Preliminary fuel cells measurements on hydrogen based Polymer Electrolyte Membrane Fuel Cell (PEMFC) displayed an interestingly reasonable good fuel cell performance, a quite reduced loss when the hydrogen stream was polluted with carbon monoxide, and finally, when the system was tested with an ethanol/water (E/W) fuel, it displayed quite promising results that allows placing this system as an attractive option in order to increase the cell performance and deal with the typical limitations of low temperature Nafion-based PEMFC. (author)

Evolution of taste and solitary chemoreceptor cell systems.

Science.gov (United States)

Finger, T E

1997-01-01

Vertebrates possess four distinct chemosensory systems distinguishable on the basis of structure, innervation and utilization: olfaction, taste, solitary chemoreceptor cells (SCC) and the common chemical sense (free nerve endings). Of these, taste and the SCC sense rely on secondary receptor cells situated in the epidermis and synapsing on sensory nerve fibers innervating them near their base. The SCC sense occurs in anamniote aquatic craniates, including hagfish, and may be used for feeding or predator avoidance. The sense of taste occurs only in vertebrates and is always utilized for feeding. The SCC system achieves a high degree of specialization in two teleosts: sea robins (Prionotus) and rocklings (Ciliata). In sea robins, SCCs are abundant on the three anterior fin rays of the pectoral fin which are free of fin webbing and are used in active exploration of the substrate. Behavioral and physiological studies show that this SCC system responds to feeding cues and drives feeding behavior. It is connected centrally like a somatosensory system. In contrast, the specialized SCC system of rocklings occurs on the anterior dorsal fin which actively samples the surrounding water. This system responds to mucus substances and may serve as a predator detector. The SCC system in rocklings is connected centrally like a gustatory system. Taste buds contain multiple receptor cell types, including a serotonergic Merkel-like cell. Taste receptor cells respond to nutritionally relevant substances. Due to similarities between SCCs and one type of taste receptor cell, the suggestion is made that taste buds may be compound sensory organs that include some cells related to SCCs and others related to cutaneous Merkel cells. The lack of taste buds in hagfish and their presence in all vertebrates may indicate that the phylogenetic development of taste buds coincided with the elaboration of head structures at the craniate-vertebrate transition.

Models and methods for design and implementation of computer based control and monitoring systems for production cells

DEFF Research Database (Denmark)

Lynggaard, Hans Jørgen Birk

This dissertation is concerned with the engineering, i.e. the designing and making, of industrial cell control systems. The focus is on automated robot welding cells in the shipbuilding industry. The industrial research project defines models and methods for design and implementation of computer...... through the implementation of two cell control systems for robot welding cells in production at Odense Steel Shipyard.It is concluded that cell control technology provides for increased performance in production systems, and that the Cell Control Engineering concept reduces the effort for providing high...... quality and high functionality cell control solutions for the industry....

A cell-phone-based brain-computer interface for communication in daily life

Science.gov (United States)

Wang, Yu-Te; Wang, Yijun; Jung, Tzyy-Ping

2011-04-01

Moving a brain-computer interface (BCI) system from a laboratory demonstration to real-life applications still poses severe challenges to the BCI community. This study aims to integrate a mobile and wireless electroencephalogram (EEG) system and a signal-processing platform based on a cell phone into a truly wearable and wireless online BCI. Its practicality and implications in a routine BCI are demonstrated through the realization and testing of a steady-state visual evoked potential (SSVEP)-based BCI. This study implemented and tested online signal processing methods in both time and frequency domains for detecting SSVEPs. The results of this study showed that the performance of the proposed cell-phone-based platform was comparable, in terms of the information transfer rate, with other BCI systems using bulky commercial EEG systems and personal computers. To the best of our knowledge, this study is the first to demonstrate a truly portable, cost-effective and miniature cell-phone-based platform for online BCIs.

In vitro protein expression: an emerging alternative to cell-based approaches.

Science.gov (United States)

He, Mingyue

2011-04-30

Protein expression remains a bottleneck in the production of proteins. Owing to several advantages, cell-free translation is emerging as an alternative to cell-based methods for the generation of proteins. Recent advances have led to many novel applications of cell-free systems in biotechnology, proteomics and fundamental biological research. This special issue of New Biotechnology describes recent advances in cell-free protein expression systems and their applications. Copyright © 2010 Elsevier B.V. All rights reserved.

Electric terminal performance and characterization of solid oxide fuel cells and systems

Science.gov (United States)

Lindahl, Peter Allan

Solid Oxide Fuel Cells (SOFCs) are electrochemical devices which can effect efficient, clean, and quiet conversion of chemical to electrical energy. In contrast to conventional electricity generation systems which feature multiple discrete energy conversion processes, SOFCs are direct energy conversion devices. That is, they feature a fully integrated chemical to electrical energy conversion process where the electric load demanded of the cell intrinsically drives the electrochemical reactions and associated processes internal to the cell. As a result, the cell's electric terminals provide a path for interaction between load side electric demand and the conversion side processes. The implication of this is twofold. First, the magnitude and dynamic characteristics of the electric load demanded of the cell can directly impact the long-term efficacy of the cell's chemical to electrical energy conversion. Second, the electric terminal response to dynamic loads can be exploited for monitoring the cell's conversion side processes and used in diagnostic analysis and degradation-mitigating control schemes. This dissertation presents a multi-tier investigation into this electric terminal based performance characterization of SOFCs through the development of novel test systems, analysis techniques and control schemes. First, a reference-based simulation system is introduced. This system scales up the electric terminal performance of a prototype SOFC system, e.g. a single fuel cell, to that of a full power-level stack. This allows realistic stack/load interaction studies while maintaining explicit ability for post-test analysis of the prototype system. Next, a time-domain least squares fitting method for electrochemical impedance spectroscopy (EIS) is developed for reduced-time monitoring of the electrochemical and physicochemical mechanics of the fuel cell through its electric terminals. The utility of the reference-based simulator and the EIS technique are demonstrated

Design of robotic cells based on relative handling modules with use of SolidWorks system

Science.gov (United States)

Gaponenko, E. V.; Anciferov, S. I.

2018-05-01

The article presents a diagramed engineering solution for a robotic cell with six degrees of freedom for machining of complex details, consisting of the base with a tool installation module and a detail machining module made as parallel structure mechanisms. The output links of the detail machining module and the tool installation module can move along X-Y-Z coordinate axes each. A 3D-model of the complex is designed in the SolidWorks system. It will be used further for carrying out engineering calculations and mathematical analysis and obtaining all required documentation.

Single cell adhesion force measurement for cell viability identification using an AFM cantilever-based micro putter

Science.gov (United States)

Shen, Yajing; Nakajima, Masahiro; Kojima, Seiji; Homma, Michio; Kojima, Masaru; Fukuda, Toshio

2011-11-01

Fast and sensitive cell viability identification is a key point for single cell analysis. To address this issue, this paper reports a novel single cell viability identification method based on the measurement of single cell shear adhesion force using an atomic force microscopy (AFM) cantilever-based micro putter. Viable and nonviable yeast cells are prepared and put onto three kinds of substrate surfaces, i.e. tungsten probe, gold and ITO substrate surfaces. A micro putter is fabricated from the AFM cantilever by focused ion beam etching technique. The spring constant of the micro putter is calibrated using the nanomanipulation approach. The shear adhesion force between the single viable or nonviable cell and each substrate is measured using the micro putter based on the nanorobotic manipulation system inside an environmental scanning electron microscope. The adhesion force is calculated based on the deflection of the micro putter beam. The results show that the adhesion force of the viable cell to the substrate is much larger than that of the nonviable cell. This identification method is label free, fast, sensitive and can give quantitative results at the single cell level.

Reproducible fashion of the HSP70B' promoter-induced cytotoxic response on a live cell-based biosensor by cell cycle synchronization.

Science.gov (United States)

Migita, Satoshi; Wada, Ken-Ichi; Taniguchi, Akiyoshi

2010-10-15

Live cell-based sensors potentially provide functional information about the cytotoxic effect of reagents on various signaling cascades. Cells transfected with a reporter vector derived from a cytotoxic response promoter can be used as intelligent cytotoxicity sensors (i.e., sensor cells). We have combined sensor cells and a microfluidic cell culture system that can achieve several laminar flows, resulting in a reliable high-throughput cytotoxicity detection system. These sensor cells can also be applied to single cell arrays. However, it is difficult to detect a cellular response in a single cell array, due to the heterogeneous response of sensor cells. The objective of this study was cell homogenization with cell cycle synchronization to enhance the response of cell-based biosensors. Our previously established stable sensor cells were brought into cell cycle synchronization under serum-starved conditions and we then investigated the cadmium chloride-induced cytotoxic response at the single cell level. The GFP positive rate of synchronized cells was approximately twice as high as that of the control cells, suggesting that cell homogenization is an important step when using cell-based biosensors with microdevices, such as a single cell array. Copyright 2010 Wiley Periodicals, Inc.

Hydrogen peroxide oxidant fuel cell systems for ultra-portable applications

Science.gov (United States)

Valdez, T. I.; Narayanan, S. R.

2001-01-01

This paper will address the issues of using hydrogen peroxide as an oxidant fuel in a miniature DMFC system. Cell performance for DMFC based fuel cells operating on hydrogen peroxide will be presented and discussed.

A New Cogeneration Residential System Based on Solid Oxide Fuel Cells for a Northern European Climate

DEFF Research Database (Denmark)

Vialetto, Giulio; Rokni, Masoud

2015-01-01

of them received subsidies to increase installation and reduce cost. This article presents an innovative cogeneration system based on a solid oxide fuel cell (SOFC) system and heat pump for household applications with a focus on primary energy and economic savings using electric equivalent load parameter...... which is a function of the electricity and heat demand of the user, and allows different operation strategies to be considered. The proposal is to maximize the efficiency of the system and to make it profitable, even though technologies with a high purchase cost are considered. Simulations of the system...... are performed under different strategies at a resort located in a northern European climate (Denmark) to cover electricity, space heating and domestic hot water (DHW) demands. The results of these simulations are analyzed with thermodynamic and techno-economic benchmarks, considering different economic...

Genetically Modified T-Cell-Based Adoptive Immunotherapy in Hematological Malignancies

Directory of Open Access Journals (Sweden)

Baixin Ye

2017-01-01

Full Text Available A significant proportion of hematological malignancies remain limited in treatment options. Immune system modulation serves as a promising therapeutic approach to eliminate malignant cells. Cytotoxic T lymphocytes (CTLs play a central role in antitumor immunity; unfortunately, nonspecific approaches for targeted recognition of tumor cells by CTLs to mediate tumor immune evasion in hematological malignancies imply multiple mechanisms, which may or may not be clinically relevant. Recently, genetically modified T-cell-based adoptive immunotherapy approaches, including chimeric antigen receptor (CAR T-cell therapy and engineered T-cell receptor (TCR T-cell therapy, promise to overcome immune evasion by redirecting the specificity of CTLs to tumor cells. In clinic trials, CAR-T-cell- and TCR-T-cell-based adoptive immunotherapy have produced encouraging clinical outcomes, thereby demonstrating their therapeutic potential in mitigating tumor development. The purpose of the present review is to (1 provide a detailed overview of the multiple mechanisms for immune evasion related with T-cell-based therapies; (2 provide a current summary of the applications of CAR-T-cell- as well as neoantigen-specific TCR-T-cell-based adoptive immunotherapy and routes taken to overcome immune evasion; and (3 evaluate alternative approaches targeting immune evasion via optimization of CAR-T and TCR-T-cell immunotherapies.

Thermoeconomic analysis of a fuel cell hybrid power system from the fuel cell experimental data

Energy Technology Data Exchange (ETDEWEB)

Alvarez, Tomas [Endesa Generacion, Ribera del Loira, 60, 28042 Madrid (Spain)]. E-mail: talvarez@endesa.es; Valero, Antonio [Fundacion CIRCE, Centro Politecnico Superior, Maria de Luna, 3, 50018 Zaragoza (Spain); Montes, Jose M. [ETSIMM-Universidad Politecnica de.Madrid, Rios Rosas, 21, 28003 Madrid (Spain)

2006-08-15

An innovative configuration of fuel cell technology is proposed based on a hybrid fuel cell system that integrates a turbogenerator to overcome the intrinsic limitations of fuel cells in conventional operation. An analysis is done of the application of molten carbonate fuel cell technology at the Guadalix Fuel Cell Test Facility, for the assessment of the performance of the fuel cell prototype to be integrated in the Hybrid Fuel Cell System. This is completed with a thermoeconomic analysis of the 100 kW cogeneration fuel cell power plant which was subsequently built. The operational results and design limitations are evaluated, together with the operational limits and thermodynamic inefficiencies (exergy destruction and losses) of the 100 kW fuel cell. This leads to the design of a hybrid system in order to demonstrate the possibilities and benefits of the new hybrid configuration. The results are quantified through a thermoeconomic analysis in order to get the most cost-effective plant configuration. One promising configuration is the MCFC topper where the fuel cell in the power plant behaves as a combustor for the turbogenerator. The latter behaves as the balance of plant for the fuel cell. The combined efficiency increased to 57% and NOx emissions are essentially eliminated. The synergy of the fuel cell/turbine hybrids lies mainly in the use of the rejected thermal energy and residual fuel from the fuel cell to drive the turbogenerator in a 500 kW hybrid system.

Model-based fault detection for proton exchange membrane fuel cell ...

African Journals Online (AJOL)

In this paper, an intelligent model-based fault detection (FD) is developed for proton exchange membrane fuel cell (PEMFC) dynamic systems using an independent radial basis function (RBF) networks. The novelty is that this RBF networks is used to model the PEMFC dynamic systems and residuals are generated based ...

Seca Coal-Based Systems Program

International Nuclear Information System (INIS)

Alinger, Matthew

2008-01-01

This report summarizes the progress made during the August 1, 2006 - May 31, 2008 award period under Cooperative Agreement DE-FC26-05NT42614 for the U. S. Department of Energy/National Energy Technology Laboratory (USDOE/NETL) entitled 'SECA Coal Based Systems'. The initial overall objective of this program was to design, develop, and demonstrate multi-MW integrated gasification fuel cell (IGFC) power plants with >50% overall efficiency from coal (HHV) to AC power. The focus of the program was to develop low-cost, high performance, modular solid oxide fuel cell (SOFC) technology to support coal gas IGFC power systems. After a detailed GE internal review of the SOFC technology, the program was de-scoped at GE's request. The primary objective of this program was then focused on developing a performance degradation mitigation path for high performing, cost-effective solid oxide fuel cells (SOFCs). There were two initial major objectives in this program. These were: (1) Develop and optimize a design of a >100 MWe integrated gasification fuel cell (IGFC) power plant; (2) Resolve identified barrier issues concerning the long-term economic performance of SOFC. The program focused on designing and cost estimating the IGFC system and resolving technical and economic barrier issues relating to SOFC. In doing so, manufacturing options for SOFC cells were evaluated, options for constructing stacks based upon various cell configurations identified, and key performance characteristics were identified. Key factors affecting SOFC performance degradation for cells in contact with metallic interconnects were be studied and a fundamental understanding of associated mechanisms was developed using a fixed materials set. Experiments and modeling were carried out to identify key processes/steps affecting cell performance degradation under SOFC operating conditions. Interfacial microstructural and elemental changes were characterized, and their relationships to observed degradation

Synthetic biology in cell-based cancer immunotherapy.

Science.gov (United States)

Chakravarti, Deboki; Wong, Wilson W

2015-08-01

The adoptive transfer of genetically engineered T cells with cancer-targeting receptors has shown tremendous promise for eradicating tumors in clinical trials. This form of cellular immunotherapy presents a unique opportunity to incorporate advanced systems and synthetic biology approaches to create cancer therapeutics with novel functions. We first review the development of synthetic receptors, switches, and circuits to control the location, duration, and strength of T cell activity against tumors. In addition, we discuss the cellular engineering and genome editing of host cells (or the chassis) to improve the efficacy of cell-based cancer therapeutics, and to reduce the time and cost of manufacturing. Copyright © 2015 Elsevier Ltd. All rights reserved.

SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION

Energy Technology Data Exchange (ETDEWEB)

Faress Rahman; Nguyen Minh

2003-07-01

This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the January 2003 to June 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. This report summarizes the results obtained to date on: System performance analysis and model optimization; Reliability and cost model development; System control including dynamic model development; Heat exchanger material tests and life analysis; Pressurized SOFC evaluation; and Pre-baseline system definition for coal gasification fuel cell system concept.

Bringing fuel cells to reality and reality to fuel cells: A systems perspective on the use of fuel cells

International Nuclear Information System (INIS)

Saxe, Maria

2008-10-01

The hopes and expectations on fuel cells are high and sometimes unrealistically positive. However, as an emerging technology, much remains to be proven and the proper use of the technology in terms of suitable applications, integration with society and extent of use is still under debate. This thesis is a contribution to the debate, presenting results from two fuel cell demonstration projects, looking into the introduction of fuel cells on the market, discussing the prospects and concerns for the near-term future and commenting on the potential use in a future sustainable energy system. Bringing fuel cells to reality implies finding near-term niche applications and markets where fuel cell systems may be competitive. In a sense fuel cells are already a reality as they have been demonstrated in various applications world-wide. However, in many of the envisioned applications fuel cells are far from being competitive and sometimes also the environmental benefit of using fuel cells in a given application may be questioned. Bringing reality to fuel cells implies emphasising the need for realistic expectations and pointing out that the first markets have to be based on the currently available technology and not the visions of what fuel cells could be in the future. The results from the demonstration projects show that further development and research on especially the durability for fuel cell systems is crucial and a general recommendation is to design the systems for high reliability and durability rather than striving towards higher energy efficiencies. When sufficient reliability and durability are achieved, fuel cell systems may be introduced in niche markets where the added values presented by the technology compensate for the initial high cost

A Versatile System for USER Cloning-Based Assembly of Expression Vectors for Mammalian Cell Engineering

DEFF Research Database (Denmark)

Lund, Anne Mathilde; Kildegaard, Helene Faustrup; Petersen, Maja Borup Kjær

2014-01-01

, in addition the system is fully extendable by other users. The vector system is designed to facilitate high-throughput genome-scale studies of mammalian cells, such as the newly sequenced CHO cell lines, through the ability to rapidly generate high-fidelity assembly of customizable gene expression vectors....

Description and modelling of the solar-hydrogen-biogas-fuel cell system in GlashusEtt

Science.gov (United States)

Hedström, L.; Wallmark, C.; Alvfors, P.; Rissanen, M.; Stridh, B.; Ekman, J.

The need to reduce pollutant emissions and utilise the world's available energy resources more efficiently has led to increased attention towards e.g. fuel cells, but also to other alternative energy solutions. In order to further understand and evaluate the prerequisites for sustainable and energy-saving systems, ABB and Fortum have equipped an environmental information centre, located in Hammarby Sjöstad, Stockholm, Sweden, with an alternative energy system. The system is being used to demonstrate and evaluate how a system based on fuel cells and solar cells can function as a complement to existing electricity and heat production. The stationary energy system is situated on the top level of a three-floor glass building and is open to the public. The alternative energy system consists of a fuel cell system, a photovoltaic (PV) cell array, an electrolyser, hydrogen storage tanks, a biogas burner, dc/ac inverters, heat exchangers and an accumulator tank. The fuel cell system includes a reformer and a polymer electrolyte fuel cell (PEFC) with a maximum rated electrical output of 4 kW el and a maximum thermal output of 6.5 kW th. The fuel cell stack can be operated with reformed biogas, or directly using hydrogen produced by the electrolyser. The cell stack in the electrolyser consists of proton exchange membrane (PEM) cells. To evaluate different automatic control strategies for the system, a simplified dynamic model has been developed in MATLAB Simulink. The model based on measurement data taken from the actual system. The evaluation is based on demand curves, investment costs, electricity prices and irradiation. Evaluation criteria included in the model are electrical and total efficiencies as well as economic parameters.

Application of an improved operational strategy for a high temperature-proton exchange membrane fuel cell-based micro-combined heat and power system for Danish single-family households

DEFF Research Database (Denmark)

Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

2013-01-01

be justified as compared to other micro-CHP system technologies. The most important findings of this research study indicate that in comparison to non-fuel cell-based micro-CHP systems, such as Stirling Engine-based systems, the proposed system has significantly higher efficiencies. Moreover, the lower heat...

Tobacco BY-2 cell-free lysate: an alternative and highly-productive plant-based in vitro translation system.

Science.gov (United States)

Buntru, Matthias; Vogel, Simon; Spiegel, Holger; Schillberg, Stefan

2014-05-03

Cell-free protein synthesis is a rapid and efficient method for the production of recombinant proteins. Usage of prokaryotic cell-free extracts often leads to non-functional proteins. Eukaryotic counterparts such as wheat germ extract (WGE) and rabbit reticulocyte lysate (RLL) may improve solubility and promote the correct folding of eukaryotic multi-domain proteins that are difficult to express in bacteria. However, the preparation of WGEs is complex and time-consuming, whereas RLLs suffer from low yields. Here we report the development of a novel cell-free system based on tobacco Bright Yellow 2 (BY-2) cells harvested in the exponential growth phase. The highly-productive BY-2 lysate (BYL) can be prepared quickly within 4-5 h, compared to 4-5 d for WGE. The efficiency of the BYL was tested using three model proteins: enhanced yellow fluorescent protein (eYFP) and two versions of luciferase. The added mRNA was optimized by testing different 5' and 3' untranslated regions (UTRs). The protein yield in batch and dialysis reactions using BYL was much higher than that of a commercial Promega WGE preparation, achieving a maximum yield of 80 μg/mL of eYFP and 100 μg/mL of luciferase, compared to only 45 μg/mL of eYFP and 35 μg/mL of luciferase in WGEs. In dialysis reactions, the BYL yielded about 400 μg/mL eYFP, representing up to 50% more of the target protein than the Promega WGE, and equivalent to the amount using 5Prime WGE system. Due to the high yield and the short preparation time the BYL represents a remarkable improvement over current eukaryotic cell-free systems.

Design of durability test protocol for vehicular fuel cell systems operated in power-follow mode based on statistical results of on-road data

Science.gov (United States)

Xu, Liangfei; Reimer, Uwe; Li, Jianqiu; Huang, Haiyan; Hu, Zunyan; Jiang, Hongliang; Janßen, Holger; Ouyang, Minggao; Lehnert, Werner

2018-02-01

City buses using polymer electrolyte membrane (PEM) fuel cells are considered to be the most likely fuel cell vehicles to be commercialized in China. The technical specifications of the fuel cell systems (FCSs) these buses are equipped with will differ based on the powertrain configurations and vehicle control strategies, but can generally be classified into the power-follow and soft-run modes. Each mode imposes different levels of electrochemical stress on the fuel cells. Evaluating the aging behavior of fuel cell stacks under the conditions encountered in fuel cell buses requires new durability test protocols based on statistical results obtained during actual driving tests. In this study, we propose a systematic design method for fuel cell durability test protocols that correspond to the power-follow mode based on three parameters for different fuel cell load ranges. The powertrain configurations and control strategy are described herein, followed by a presentation of the statistical data for the duty cycles of FCSs in one city bus in the demonstration project. Assessment protocols are presented based on the statistical results using mathematical optimization methods, and are compared to existing protocols with respect to common factors, such as time at open circuit voltage and root-mean-square power.

Simulation of SOFCs based power generation system using Aspen

Directory of Open Access Journals (Sweden)

Pianko-Oprych Paulina

2017-12-01

Full Text Available This study presents a thermodynamic Aspen simulation model for Solid Oxide Fuel Cells, SOFCs, based power generation system. In the first step, a steady-state SOFCs system model was developed. The model includes the electrochemistry and the diffusion phenomena. The electrochemical model gives good agreement with experimental data in a wide operating range. Then, a parametric study has been conducted to estimate effects of the oxygen to carbon ratio, O/C, on reformer temperature, fuel cell temperature, fuel utilization, overall fuel cell performance, and the results are discussed in this paper. In the second step, a dynamic analysis of SOFCs characteristic has been developed. The aim of dynamic modelling was to find the response of the system against the fuel utilization and the O/C ratio variations. From the simulations, it was concluded that both developed models in the steady and dynamic state were reasonably accurate and can be used for system level optimization studies of the SOFC based power generation system.

Fuel quality issues in stationary fuel cell systems.

Energy Technology Data Exchange (ETDEWEB)

Papadias, D.; Ahmed, S.; Kumar, R. (Chemical Sciences and Engineering Division)

2012-02-07

Fuel cell systems are being deployed in stationary applications for the generation of electricity, heat, and hydrogen. These systems use a variety of fuel cell types, ranging from the low temperature polymer electrolyte fuel cell (PEFC) to the high temperature solid oxide fuel cell (SOFC). Depending on the application and location, these systems are being designed to operate on reformate or syngas produced from various fuels that include natural gas, biogas, coal gas, etc. All of these fuels contain species that can potentially damage the fuel cell anode or other unit operations and processes that precede the fuel cell stack. These detrimental effects include loss in performance or durability, and attenuating these effects requires additional components to reduce the impurity concentrations to tolerable levels, if not eliminate the impurity entirely. These impurity management components increase the complexity of the fuel cell system, and they add to the system's capital and operating costs (such as regeneration, replacement and disposal of spent material and maintenance). This project reviewed the public domain information available on the impurities encountered in stationary fuel cell systems, and the effects of the impurities on the fuel cells. A database has been set up that classifies the impurities, especially in renewable fuels, such as landfill gas and anaerobic digester gas. It documents the known deleterious effects on fuel cells, and the maximum allowable concentrations of select impurities suggested by manufacturers and researchers. The literature review helped to identify the impurity removal strategies that are available, and their effectiveness, capacity, and cost. A generic model of a stationary fuel-cell based power plant operating on digester and landfill gas has been developed; it includes a gas processing unit, followed by a fuel cell system. The model includes the key impurity removal steps to enable predictions of impurity breakthrough

Systems biomechanics of the cell

CERN Document Server

Maly, Ivan V

2013-01-01

Systems Biomechanics of the Cell attempts to outline systems biomechanics of the cell as an emergent and promising discipline. The new field owes conceptually to cell mechanics, organism-level systems biomechanics, and biology of biochemical systems. Its distinct methodology is to elucidate the structure and behavior of the cell by analyzing the unintuitive collective effects of elementary physical forces that interact within the heritable cellular framework. The problematics amenable to this approach includes the variety of cellular activities that involve the form and movement of the cell body and boundary (nucleus, centrosome, microtubules, cortex, and membrane). Among the elementary system effects in the biomechanics of the cell, instability of symmetry, emergent irreversibility, and multiperiodic dissipative motion can be noted. Research results from recent journal articles are placed in this unifying framework. It is suggested that the emergent discipline has the potential to expand the spectrum of ques...

Preliminary analysis of compound systems based on high temperature fuel cell, gas turbine and Organic Rankine Cycle

Science.gov (United States)

Sánchez, D.; Muñoz de Escalona, J. M.; Monje, B.; Chacartegui, R.; Sánchez, T.

This article presents a novel proposal for complex hybrid systems comprising high temperature fuel cells and thermal engines. In this case, the system is composed by a molten carbonate fuel cell with cascaded hot air turbine and Organic Rankine Cycle (ORC), a layout that is based on subsequent waste heat recovery for additional power production. The work will credit that it is possible to achieve 60% efficiency even if the fuel cell operates at atmospheric pressure. The first part of the analysis focuses on selecting the working fluid of the Organic Rankine Cycle. After a thermodynamic optimisation, toluene turns out to be the most efficient fluid in terms of cycle performance. However, it is also detected that the performance of the heat recovery vapour generator is equally important, what makes R245fa be the most interesting fluid due to its balanced thermal and HRVG efficiencies that yield the highest global bottoming cycle efficiency. When this fluid is employed in the compound system, conservative operating conditions permit achieving 60% global system efficiency, therefore accomplishing the initial objective set up in the work. A simultaneous optimisation of gas turbine (pressure ratio) and ORC (live vapour pressure) is then presented, to check if the previous results are improved or if the fluid of choice must be replaced. Eventually, even if system performance improves for some fluids, it is concluded that (i) R245fa is the most efficient fluid and (ii) the operating conditions considered in the previous analysis are still valid. The work concludes with an assessment about safety-related aspects of using hydrocarbons in the system. Flammability is studied, showing that R245fa is the most interesting fluid also in this regard due to its inert behaviour, as opposed to the other fluids under consideration all of which are highly flammable.

On Orbit Immuno-Based, Label-Free, White Blood Cell Counting System with MicroElectroMechanical Sensor (MEMS) Technology (OILWBCS-MEMS), Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Aurora Flight Sciences Corporation and partner, Draper Laboratory, propose to develop an on-orbit immuno-based label-free white blood cell counting system using MEMS...

On Orbit Immuno-Based, Label-Free, White Blood Cell Counting System with MicroElectroMechanical Sensor (MEMS) Technology (OILWBCS-MEMS), Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Aurora Flight Sciences Corporation and our partner, Draper Laboratory, propose to develop an on orbit immuno-based, label-free, white blood cell counting system for...

An inflammation-based cumulative prognostic score system in patients with diffuse large B cell lymphoma in rituximab era.

Science.gov (United States)

Sun, Feifei; Zhu, Jia; Lu, Suying; Zhen, Zijun; Wang, Juan; Huang, Junting; Ding, Zonghui; Zeng, Musheng; Sun, Xiaofei

2018-01-02

Systemic inflammatory parameters are associated with poor outcomes in malignant patients. Several inflammation-based cumulative prognostic score systems were established for various solid tumors. However, there is few inflammation based cumulative prognostic score system for patients with diffuse large B cell lymphoma (DLBCL). We retrospectively reviewed 564 adult DLBCL patients who had received rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP) therapy between Nov 1 2006 and Dec 30 2013 and assessed the prognostic significance of six systemic inflammatory parameters evaluated in previous studies by univariate and multivariate analysis:C-reactive protein(CRP), albumin levels, the lymphocyte-monocyte ratio (LMR), the neutrophil-lymphocyte ratio(NLR), the platelet-lymphocyte ratio(PLR)and fibrinogen levels. Multivariate analysis identified CRP, albumin levels and the LMR are three independent prognostic parameters for overall survival (OS). Based on these three factors, we constructed a novel inflammation-based cumulative prognostic score (ICPS) system. Four risk groups were formed: group ICPS = 0, ICPS = 1, ICPS = 2 and ICPS = 3. Advanced multivariate analysis indicated that the ICPS model is a prognostic score system independent of International Prognostic Index (IPI) for both progression-free survival (PFS) (p systemic inflammatory status was associated with clinical outcomes of patients with DLBCL in rituximab era. The ICPS model was shown to classify risk groups more accurately than any single inflammatory prognostic parameters. These findings may be useful for identifying candidates for further inflammation-related mechanism research or novel anti-inflammation target therapies.

Full and part load exergetic analysis of a hybrid micro gas turbine fuel cell system based on existing components

International Nuclear Information System (INIS)

Bakalis, Diamantis P.; Stamatis, Anastassios G.

2012-01-01

Highlights: ► Hybrid SOFC/GT system based on existing components. ► Exergy analysis using AspenPlus™ software. ► Greenhouse gases emission is significantly affected by SOFC stack temperature. ► Comparison with a conventional GT of similar power. ► SOFC/GT is almost twice efficient in terms of second low efficiency and CO 2 emission. - Abstract: The paper deals with the examination of a hybrid system consisting of a pre-commercially available high temperature solid oxide fuel cell and an existing recuperated microturbine. The irreversibilities and thermodynamic inefficiencies of the system are evaluated after examining the full and partial load exergetic performance and estimating the amount of exergy destruction and the efficiency of each hybrid system component. At full load operation the system achieves an exergetic efficiency of 59.8%, which increases during the partial load operation, as a variable speed control method is utilized. Furthermore, the effects of the various performance parameters such as fuel cell stack temperature and fuel utilization factor are assessed. The results showed that the components in which chemical reactions occur have the higher exergy destruction rates. The exergetic performance of the system is affected significantly by the stack temperature. Based on the exergetic analysis, suggestions are given for reducing the overall system irreversibility. Finally, the environmental impact of the operation of the hybrid system is evaluated and compared with a similarly rated conventional gas turbine plant. From the comparison it is apparent that the hybrid system obtains nearly double exergetic efficiency and about half the amount of greenhouse gas emissions compared with the conventional plant.

Drug and bioactive molecule screening based on a bioelectrical impedance cell culture platform

Directory of Open Access Journals (Sweden)

Ramasamy S

2014-12-01

Full Text Available Sakthivel Ramasamy,1 Devasier Bennet,1 Sanghyo Kim1,2 1Department of Bionanotechnology, Gachon University, Gyeonggi-Do, Republic of Korea; 2Graduate Gachon Medical Research Institute, Gil Medical Center, Incheon, Republic of Korea Abstract: This review will present a brief discussion on the recent advancements of bioelectrical impedance cell-based biosensors, especially the electric cell-substrate impedance sensing (ECIS system for screening of various bioactive molecules. The different technical integrations of various chip types, working principles, measurement systems, and applications for drug targeting of molecules in cells are highlighted in this paper. Screening of bioactive molecules based on electric cell-substrate impedance sensing is a trial-and-error process toward the development of therapeutically active agents for drug discovery and therapeutics. In general, bioactive molecule screening can be used to identify active molecular targets for various diseases and toxicity at the cellular level with nanoscale resolution. In the innovation and screening of new drugs or bioactive molecules, the activeness, the efficacy of the compound, and safety in biological systems are the main concerns on which determination of drug candidates is based. Further, drug discovery and screening of compounds are often performed in cell-based test systems in order to reduce costs and save time. Moreover, this system can provide more relevant results in in vivo studies, as well as high-throughput drug screening for various diseases during the early stages of drug discovery. Recently, MEMS technologies and integration with image detection techniques have been employed successfully. These new technologies and their possible ongoing transformations are addressed. Select reports are outlined, and not all the work that has been performed in the field of drug screening and development is covered. Keywords: screening of bioactive agents, impedance-based cell

Advanced chemical hydride-based hydrogen generation/storage system for fuel cell vehicles

Energy Technology Data Exchange (ETDEWEB)

Breault, R.W.; Rolfe, J. [Thermo Power Corp., Waltham, MA (United States)

1998-08-01

Because of the inherent advantages of high efficiency, environmental acceptability, and high modularity, fuel cells are potentially attractive power supplies. Worldwide concerns over clean environments have revitalized research efforts on developing fuel cell vehicles (FCV). As a result of intensive research efforts, most of the subsystem technology for FCV`s are currently well established. These include: high power density PEM fuel cells, control systems, thermal management technology, and secondary power sources for hybrid operation. For mobile applications, however, supply of hydrogen or fuel for fuel cell operation poses a significant logistic problem. To supply high purity hydrogen for FCV operation, Thermo Power`s Advanced Technology Group is developing an advanced hydrogen storage technology. In this approach, a metal hydride/organic slurry is used as the hydrogen carrier and storage media. At the point of use, high purity hydrogen will be produced by reacting the metal hydride/organic slurry with water. In addition, Thermo Power has conceived the paths for recovery and regeneration of the spent hydride (practically metal hydroxide). The fluid-like nature of the spent hydride/organic slurry will provide a unique opportunity for pumping, transporting, and storing these materials. The final product of the program will be a user-friendly and relatively high energy storage density hydrogen supply system for fuel cell operation. In addition, the spent hydride can relatively easily be collected at the pumping station and regenerated utilizing renewable sources, such as biomass, natural, or coal, at the central processing plants. Therefore, the entire process will be economically favorable and environmentally friendly.

Fuzzy energy management for hybrid fuel cell/battery systems for more electric aircraft

Science.gov (United States)

Corcau, Jenica-Ileana; Dinca, Liviu; Grigorie, Teodor Lucian; Tudosie, Alexandru-Nicolae

2017-06-01

In this paper is presented the simulation and analysis of a Fuzzy Energy Management for Hybrid Fuel cell/Battery Systems used for More Electric Aircraft. The fuel cell hybrid system contains of fuel cell, lithium-ion batteries along with associated dc to dc boost converters. In this configuration the battery has a dc to dc converter, because it is an active in the system. The energy management scheme includes the rule based fuzzy logic strategy. This scheme has a faster response to load change and is more robust to measurement imprecisions. Simulation will be provided using Matlab/Simulink based models. Simulation results are given to show the overall system performance.

A fully automated cell segmentation and morphometric parameter system for quantifying corneal endothelial cell morphology.

Science.gov (United States)

Al-Fahdawi, Shumoos; Qahwaji, Rami; Al-Waisy, Alaa S; Ipson, Stanley; Ferdousi, Maryam; Malik, Rayaz A; Brahma, Arun

2018-07-01

Corneal endothelial cell abnormalities may be associated with a number of corneal and systemic diseases. Damage to the endothelial cells can significantly affect corneal transparency by altering hydration of the corneal stroma, which can lead to irreversible endothelial cell pathology requiring corneal transplantation. To date, quantitative analysis of endothelial cell abnormalities has been manually performed by ophthalmologists using time consuming and highly subjective semi-automatic tools, which require an operator interaction. We developed and applied a fully-automated and real-time system, termed the Corneal Endothelium Analysis System (CEAS) for the segmentation and computation of endothelial cells in images of the human cornea obtained by in vivo corneal confocal microscopy. First, a Fast Fourier Transform (FFT) Band-pass filter is applied to reduce noise and enhance the image quality to make the cells more visible. Secondly, endothelial cell boundaries are detected using watershed transformations and Voronoi tessellations to accurately quantify the morphological parameters of the human corneal endothelial cells. The performance of the automated segmentation system was tested against manually traced ground-truth images based on a database consisting of 40 corneal confocal endothelial cell images in terms of segmentation accuracy and obtained clinical features. In addition, the robustness and efficiency of the proposed CEAS system were compared with manually obtained cell densities using a separate database of 40 images from controls (n = 11), obese subjects (n = 16) and patients with diabetes (n = 13). The Pearson correlation coefficient between automated and manual endothelial cell densities is 0.9 (p system, and the possibility of utilizing it in a real world clinical setting to enable rapid diagnosis and for patient follow-up, with an execution time of only 6 seconds per image. Copyright © 2018 Elsevier B.V. All rights reserved.

Microfluidic 3D cell culture: potential application for tissue-based bioassays

Science.gov (United States)

Li, XiuJun (James); Valadez, Alejandra V.; Zuo, Peng; Nie, Zhihong

2014-01-01

Current fundamental investigations of human biology and the development of therapeutic drugs, commonly rely on two-dimensional (2D) monolayer cell culture systems. However, 2D cell culture systems do not accurately recapitulate the structure, function, physiology of living tissues, as well as highly complex and dynamic three-dimensional (3D) environments in vivo. The microfluidic technology can provide micro-scale complex structures and well-controlled parameters to mimic the in vivo environment of cells. The combination of microfluidic technology with 3D cell culture offers great potential for in vivo-like tissue-based applications, such as the emerging organ-on-a-chip system. This article will review recent advances in microfluidic technology for 3D cell culture and their biological applications. PMID:22793034

Self-sustained cabinet based on fuel cell technology and solar energy

Energy Technology Data Exchange (ETDEWEB)

Correa, Rafael Augusto de Oliveira; Valentim, Rafael Bertier; Glir, Joao Raphael Zanlorensi; Stall, Alexandre; Sommer, Elise Meister; Sanches, Luciana Schimidilin; Dias, Fernando Gallego; Korndorfer, Heitor Medeiros de Albuquerque; Vargas, Jose Viriato Coelho [Universidade Federal do Parana (DEMEC/UFPR), Curitiba, PR (Brazil). Dept. de Engenharia Mecanica], Email: rafaelcorrea123@hotmail.com; Ordonez, Juan Carlos [Florida State University, Tallahasse, Florida (United States). Dept. of Mechanical Engineering. Center for Advanced Power Systems

2010-07-01

Along the past few years, there has been intensive research on clean and renewable energy production. Two main reasons have been pointed out: pollution caused by oil based fuels consumption and their availability diminution, which increases their production costs. Fuel Cells have shown to be a clean and renewable energy source, which reveals them as a promising solution, although their technology needs further development. Fuel Cells produce electricity, water and heat consuming hydrogen and oxygen, this provided pure or from a natural air source. Present research has combined different equipment to compose a self-sustaining fuel cells technology based cabinet for energy production, which is a Regenerative Fuel Cell System (RFC). This system contains: fuel cells stack, electrolyzer, photovoltaic panel, batteries, current inverter and a charge controller. Photovoltaic panel charges the batteries, while charge controller controls the batteries loading. Batteries are connected to an inverter which converts direct current into alternating current. Inverter is connected to an electrolyzer (Hogen GC 600) which splits the water molecule into hydrogen and oxygen molecules. Produced hydrogen supplies the fuel cell stack and the oxygen is released directly to the atmosphere. Fuel cell stacks power production is transformed into mechanical energy by a fan. Electrical power generated by Ballard stack is 5.124 W, with a voltage of 36.6 V and current of 0.14 A. The system proved to have a great efficiency and to be capable to assemble two renewable energy sources (solar and fuel cell technology) in a self-sustainable cabinet. It has also been shown that equipment such as Electrolyzer, Fuel Cell Stack and Photovoltaic panel can be fit together in the order to produce energy. Therefore, research on Fuel Cells Regenerative System reveals great importance for developing a new, clean, renewable and regenerative energy production system. (author)

Closed-channel culture system for efficient and reproducible differentiation of human pluripotent stem cells into islet cells

International Nuclear Information System (INIS)

Hirano, Kunio; Konagaya, Shuhei; Turner, Alexander; Noda, Yuichiro; Kitamura, Shigeru; Kotera, Hidetoshi; Iwata, Hiroo

2017-01-01

Human pluripotent stem cells (hPSCs) are thought to be a promising cell-source solution for regenerative medicine due to their indefinite proliferative potential and ability to differentiate to functional somatic cells. However, issues remain with regard to achieving reproducible differentiation of cells with the required functionality for realizing human transplantation therapies and with regard to reducing the potential for bacterial or fungal contamination. To meet these needs, we have developed a closed-channel culture device and corresponding control system. Uniformly-sized spheroidal hPSCs aggregates were formed inside wells within a closed-channel and maintained continuously throughout the culture process. Functional islet-like endocrine cell aggregates were reproducibly induced following a 30-day differentiation protocol. Our system shows an easily scalable, novel method for inducing PSC differentiation with both purity and functionality. - Highlights: • A simple, closed-channel-based, semi-automatic culture system is proposed. • Uniform cell aggregate formation and culture is realized in microwell structure. • Functional islet cells are successfully induced following 30-plus-day protocol. • System requires no daily medium replacement and reduces contamination risk.

Dynamic analysis of PEMFC-based CHP systems for domestic application

International Nuclear Information System (INIS)

Barelli, L.; Bidini, G.; Gallorini, F.; Ottaviano, A.

2012-01-01

Highlights: ► Dynamic model of a CHP energy system based on a PEM fuel cell was developed. ► The CHP system behavior at variable electrical and thermal load was investigated. ► The optimal RH value was assessed maximizing PEMFC performance through simulations. ► The system best operating conditions are characterized by a RH value equal to 50%. -- Abstract: Fuel cell-based CHP systems for distributed residential power generation represent an interesting alternative to traditional thermoelectric plants. This is mainly due to the high efficiency obtainable in the production of electricity and heat in a decentralised, quiet and environmental friendly way. The current paper focuses on the development, in Matlab®Simulink environment, of a complete dynamic model of a residential cogenerative (CHP) energy system consisting of the Proton Exchange Membrane fuel cell (PEMFC), fuel processor, heat exchangers, humidifier and auxiliary hot water boiler. The target of the study is the investigation through such a model of the behavior of CHP systems based on fuel cell (FC) at variable electrical and thermal load, in reference to typical load curves of residential users. With the aim to evaluate the system performance (efficiency, fuel consumption, hot water production, response time) and then to characterize its better operating conditions with particular attention to air relative humidity, suitable simulations were carried out. They are characterized by the following of a typical electrical load trend and in relation to two different thermal load profiles. The dynamic model presented in this paper has allowed to observe the fully functioning of the FC based system under variable loads and it has permitted to design appropriate control logics for this system.

Cell membrane-based nanoparticles: a new biomimetic platform for tumor diagnosis and treatment

Directory of Open Access Journals (Sweden)

Ruixiang Li

2018-01-01

Full Text Available Taking inspiration from nature, the biomimetic concept has been integrated into drug delivery systems in cancer therapy. Disguised with cell membranes, the nanoparticles can acquire various functions of natural cells. The cell membrane-coating technology has pushed the limits of common nano-systems (fast elimination in circulation to more effectively navigate within the body. Moreover, because of the various functional molecules on the surface, cell membrane-based nanoparticles (CMBNPs are capable of interacting with the complex biological microenvironment of the tumor. Various sources of cell membranes have been explored to camouflage CMBNPs and different tumor-targeting strategies have been developed to enhance the anti-tumor drug delivery therapy. In this review article we highlight the most recent advances in CMBNP-based cancer targeting systems and address the challenges and opportunities in this field.

Texosome-based drug delivery system for cancer therapy: from past to present

International Nuclear Information System (INIS)

Mahmoodzadeh Hosseini, Hamideh; Halabian, Raheleh; Amin, Mohsen; Imani Fooladi, Abbas Ali

2015-01-01

Rising worldwide cancer incidence and resistance to current anti-cancer drugs necessitate the need for new pharmaceutical compounds and drug delivery system. Malfunction of the immune system, particularly in the tumor microenvironment, causes tumor growth and enhances tumor progression. Thus, cancer immunotherapy can be an appropriate approach to provoke the systemic immune system to combat tumor expansion. Texosomes, which are endogenous nanovesicles released by all tumor cells, contribute to cell-cell communication and modify the phenotypic features of recipient cells due to the texosomes’ ability to transport biological components. For this reason, texosome-based delivery system can be a valuable strategy for therapeutic purposes. To improve the pharmaceutical behavior of this system and to facilitate its use in medical applications, biotechnology approaches and mimetic techniques have been utilized. In this review, we present the development history of texosome-based delivery systems and discuss the advantages and disadvantages of each system

Culture expansion of adipose derived stromal cells. A closed automated Quantum Cell Expansion System compared with manual flask-based culture

DEFF Research Database (Denmark)

Haack-Sørensen, Mandana; Follin, Bjarke; Juhl, Morten

2016-01-01

) over two passages in the automated and functionally closed Quantum Cell Expansion System (Quantum system) is compared with traditional manual cultivation. Methods: Stromal vascular fraction was isolated from abdominal fat, suspended in α-MEM supplemented with 10% Fetal Bovine Serum and seeded...... into either T75 flasks or a Quantum system that had been coated with cryoprecipitate. The cultivation of ASCs from SVF was performed in 3 ways: flask to flask; flask to Quantum system; and Quantum system to Quantum system. In all cases, quality controls were conducted for sterility, mycoplasmas......, and endotoxins, in addition to the assessment of cell counts, viability, immunophenotype, and differentiation potential. Results: The viability of ASCs passage 0 (P0) and P1 was above 96%, regardless of cultivation in flasks or Quantum system. Expression of surface markers and differentiation potential...

Materials system for intermediate temperature solid oxide fuel cells based on doped lanthanum-gallate electrolyte

Science.gov (United States)

Gong, Wenquan

2005-07-01

The objective of this work was to identify a materials system for intermediate temperature solid oxide fuel cells (IT-SOFCs). Towards this goal, alternating current complex impedance spectroscopy was employed as a tool to study electrode polarization effects in symmetrical cells employing strontium and magnesium doped lanthanum gallate (LSGM) electrolyte. Several cathode materials were investigated including strontium doped lanthanum manganite (LSM), Strontium and iron doped lanthanum cobaltate (LSCF), LSM-LSGM, and LSCF-LSGM composites. Investigated Anode materials included nickel-gadolinium or lanthanum doped cerium oxide (Ni-GDC, or Ni-LDC) composites. The ohmic and the polarization resistances of the symmetrical cells were obtained as a function of temperature, time, thickness, and the composition of the electrodes. Based on these studies, the single phase LSM electrode had the highest polarization resistance among the cathode materials. The mixed-conducting LSCF electrode had polarization resistance orders of magnitude lower than that of the LSM-LSGM composite electrodes. Although incorporating LSGM in the LSCF electrode did not reduce the cell polarization resistance significantly, it could reduce the thermal expansion coefficient mismatch between the LSCF electrodes and LSGM electrolyte. Moreover, the polarization resistance of the LSCF electrode decreased asymptotically as the electrode thickness was increased thus suggesting that the electrode thickness needed not be thicker than this asymptotic limit. On the anode side of the IT-SOFC, Ni reacted with LSGM electrolyte, and lanthanum diffusion occurred from the LSGM electrolyte to the GDC barrier layer, which was between the LSGM electrolyte and the Ni-composite anode. However, LDC served as an effective barrier layer. Ni-LDC (70 v% Ni) anode had the largest polarization resistance, while all other anode materials, i.e. Ni-LDC (50 v% Ni), Ni-GDC (70 v% NO, and Ni-GDC (50 v% Ni), had similar polarization

QSpec: online control and data analysis system for single-cell Raman spectroscopy

Directory of Open Access Journals (Sweden)

Lihui Ren

2014-06-01

Full Text Available Single-cell phenotyping is critical to the success of biological reductionism. Raman-activated cell sorting (RACS has shown promise in resolving the dynamics of living cells at the individual level and to uncover population heterogeneities in comparison to established approaches such as fluorescence-activated cell sorting (FACS. Given that the number of single-cells would be massive in any experiment, the power of Raman profiling technique for single-cell analysis would be fully utilized only when coupled with a high-throughput and intelligent process control and data analysis system. In this work, we established QSpec, an automatic system that supports high-throughput Raman-based single-cell phenotyping. Additionally, a single-cell Raman profile database has been established upon which data-mining could be applied to discover the heterogeneity among single-cells under different conditions. To test the effectiveness of this control and data analysis system, a sub-system was also developed to simulate the phenotypes of single-cells as well as the device features.

A trigeneration system based on polymer electrolyte fuel cell and desiccant wheel – Part B: Overall system design and energy performance analysis

International Nuclear Information System (INIS)

Intini, M.; De Antonellis, S.; Joppolo, C.M.; Casalegno, A.

2015-01-01

Highlights: • Seasonal simulation of a trigeneration system for building air-conditioning. • Effects of technical constraints on trigeneration system power consumption. • Optimal PEMFC unit size for maximizing trigeneration primary energy savings. - Abstract: This paper represents the second part of a major work focusing on a trigeneration system integrating a low temperature polymer electrolyte fuel cell (PEMFC) and a desiccant wheel-based air handling unit. Low temperature PEMFC systems have a significant potential in combined heating, cooling and power applications. However cogenerated heat temperature is relatively low (up to 65–70 °C), resulting in low efficiency of the cooling process, and the fuel processor is far from being flexible, hindering the operation of the system at low load conditions. Therefore a trigeneration system based on PEMFC should be carefully designed through accurate simulation tools. In the current paper a detailed analysis of the energy performance of the trigenerative system is provided, taking into account constraints of real applications, such as PEMFC part load behavior, desiccant wheel effectiveness, heat storage losses and air handling unit electrical consumptions. The methodology adopted to model system components is deeply described. Energy simulations are performed on yearly basis with variable building air conditioning loads and climate conditions, in order to investigate the optimal trigenerative unit size. A sensitivity analysis on crucial design parameters is provided. It is shown that constrains of actual applications have relevant effects on system energy consumption, which is significantly far from expected values based on a simplified analysis. Primary energy savings can be positive in winter time if the ratio of PEMFC heating capacity to air conditioning peak heating load is close to 0.15. Instead on yearly basis primary energy savings cannot be achieved with present components performance. Positive savings

Seca Coal-Based Systems Program

Energy Technology Data Exchange (ETDEWEB)

Matthew Alinger

2008-05-31

This report summarizes the progress made during the August 1, 2006 - May 31, 2008 award period under Cooperative Agreement DE-FC26-05NT42614 for the U. S. Department of Energy/National Energy Technology Laboratory (USDOE/NETL) entitled 'SECA Coal Based Systems'. The initial overall objective of this program was to design, develop, and demonstrate multi-MW integrated gasification fuel cell (IGFC) power plants with >50% overall efficiency from coal (HHV) to AC power. The focus of the program was to develop low-cost, high performance, modular solid oxide fuel cell (SOFC) technology to support coal gas IGFC power systems. After a detailed GE internal review of the SOFC technology, the program was de-scoped at GE's request. The primary objective of this program was then focused on developing a performance degradation mitigation path for high performing, cost-effective solid oxide fuel cells (SOFCs). There were two initial major objectives in this program. These were: (1) Develop and optimize a design of a >100 MWe integrated gasification fuel cell (IGFC) power plant; (2) Resolve identified barrier issues concerning the long-term economic performance of SOFC. The program focused on designing and cost estimating the IGFC system and resolving technical and economic barrier issues relating to SOFC. In doing so, manufacturing options for SOFC cells were evaluated, options for constructing stacks based upon various cell configurations identified, and key performance characteristics were identified. Key factors affecting SOFC performance degradation for cells in contact with metallic interconnects were be studied and a fundamental understanding of associated mechanisms was developed using a fixed materials set. Experiments and modeling were carried out to identify key processes/steps affecting cell performance degradation under SOFC operating conditions. Interfacial microstructural and elemental changes were characterized, and their relationships to observed

Exosome-Based Cell-Cell Communication in the Tumor Microenvironment

Directory of Open Access Journals (Sweden)

Joana Maia

2018-02-01

Full Text Available Tumors are not isolated entities, but complex systemic networks involving cell-cell communication between transformed and non-transformed cells. The milieu created by tumor-associated cells may either support or halt tumor progression. In addition to cell-cell contact, cells communicate through secreted factors via a highly complex system involving characteristics such as ligand concentration, receptor expression and integration of diverse signaling pathways. Of these, extracellular vesicles, such as exosomes, are emerging as novel cell-cell communication mediators in physiological and pathological scenarios. Exosomes, membrane vesicles of endocytic origin released by all cells (both healthy and diseased, ranging in size from 30 to 150 nm, transport all the main biomolecules, including lipids, proteins, DNAs, messenger RNAs and microRNA, and perform intercellular transfer of components, locally and systemically. By acting not only in tumor cells, but also in tumor-associated cells such as fibroblasts, endothelium, leukocytes and progenitor cells, tumor- and non-tumor cells-derived exosomes have emerged as new players in tumor growth and invasion, tumor-associated angiogenesis, tissue inflammation and immunologic remodeling. In addition, due to their property of carrying molecules from their cell of origin to the peripheral circulation, exosomes have been increasingly studied as sources of tumor biomarkers in liquid biopsies. Here we review the current literature on the participation of exosomes in the communication between tumor and tumor-associated cells, highlighting the role of this process in the setup of tumor microenvironments that modulate tumor initiation and metastasis.

Targeting Rapamycin to Podocytes Using a Vascular Cell Adhesion Molecule-1 (VCAM-1-Harnessed SAINT-Based Lipid Carrier System.

Directory of Open Access Journals (Sweden)

Ganesh Ram R Visweswaran

Full Text Available Together with mesangial cells, glomerular endothelial cells and the basement membrane, podocytes constitute the glomerular filtration barrier (GFB of the kidney. Podocytes play a pivotal role in the progression of various kidney-related diseases such as glomerular sclerosis and glomerulonephritis that finally lead to chronic end-stage renal disease. During podocytopathies, the slit-diaphragm connecting the adjacent podocytes are detached leading to severe loss of proteins in the urine. The pathophysiology of podocytopathies makes podocytes a potential and challenging target for nanomedicine development, though there is a lack of known molecular targets for cell selective drug delivery. To identify VCAM-1 as a cell-surface receptor that is suitable for binding and internalization of nanomedicine carrier systems by podocytes, we investigated its expression in the immortalized podocyte cell lines AB8/13 and MPC-5, and in primary podocytes. Gene and protein expression analyses revealed that VCAM-1 expression is increased by podocytes upon TNFα-activation for up to 24 h. This was paralleled by anti-VCAM-1 antibody binding to the TNFα-activated cells, which can be employed as a ligand to facilitate the uptake of nanocarriers under inflammatory conditions. Hence, we next explored the possibilities of using VCAM-1 as a cell-surface receptor to deliver the potent immunosuppressant rapamycin to TNFα-activated podocytes using the lipid-based nanocarrier system Saint-O-Somes. Anti-VCAM-1-rapamycin-SAINT-O-Somes more effectively inhibited the cell migration of AB8/13 cells than free rapamycin and non-targeted rapamycin-SAINT-O-Somes indicating the potential of VCAM-1 targeted drug delivery to podocytes.

Onion root tip cell system for biodosimetry?

International Nuclear Information System (INIS)

Paradiz, J; Druskovic, B.; Lovka, M.; Skrk, J.

1996-01-01

Methodology for radiation dose assessment based on chromosomal damage to plant cells has no yet been established, although root meristems have been the pioneer cytogenetic materials and profound analyses of irradiated meristematic cells of horse bean (Viciafaba L.) had been performed. Onion (Allium cepa L.) root tips frequently used for radiation cytogenetic studies, are recently considered to be one of the most promising plant test system for the detection of genotoxic environmental pollutants. We studied the possibility of using cytogenetic analyses of irradiated onion cells to determine the effective biological dose of ionizing radiation. The dose-effect relationships for chromosomal damages to onion meristematic cells were established after plants had been irradiated and subsequently grown in both laboratory and field conditions

Hardware in the loop simulation test platform of fuel cell backup system

Directory of Open Access Journals (Sweden)

Ma Tiancai

2015-01-01

Full Text Available Based on an analysis of voltage mechanistic model, a real-time simulation model of the proton exchange membrane (PEM fuel cell backup system is developed, and verified by the measurable experiment data. The method of online parameters identification for the model is also improved. Based on the software LabVIEW/VeriStand real-time environment and the PXI Express hardware system, the PEM fuel cell system controller hardware in the loop (HIL simulation plat-form is established. Controller simulation test results showed the accuracy of HIL simulation platform.

Chip based single cell analysis for nanotoxicity assessment.

Science.gov (United States)

Shah, Pratikkumar; Kaushik, Ajeet; Zhu, Xuena; Zhang, Chengxiao; Li, Chen-Zhong

2014-05-07

Nanomaterials, because of their tunable properties and performances, have been utilized extensively in everyday life related consumable products and technology. On exposure, beyond the physiological range, nanomaterials cause health risks via affecting the function of organisms, genomic systems, and even the central nervous system. Thus, new analytical approaches for nanotoxicity assessment to verify the feasibility of nanomaterials for future use are in demand. The conventional analytical techniques, such as spectrophotometric assay-based techniques, usually require a lengthy and time-consuming process and often produce false positives, and often cannot be implemented at a single cell level measurement for studying cell behavior without interference from its surrounding environment. Hence, there is a demand for a precise, accurate, sensitive assessment for toxicity using single cells. Recently, due to the advantages of automation of fluids and minimization of human errors, the integration of a cell-on-a-chip (CoC) with a microfluidic system is in practice for nanotoxicity assessments. This review explains nanotoxicity and its assessment approaches with advantages/limitations and new approaches to overcome the confines of traditional techniques. Recent advances in nanotoxicity assessment using a CoC integrated with a microfluidic system are also discussed in this review, which may be of use for nanotoxicity assessment and diagnostics.

Immune cells: more than simple carriers for systemic delivery of oncolytic viruses

Directory of Open Access Journals (Sweden)

Eisenstein S

2014-11-01

Full Text Available Samuel Eisenstein,1 Shu-Hsia Chen,2 Ping-Ying Pan21Department of Surgery, 2Department of Oncological Sciences and Tisch Cancer Institute, The Icahn School of Medicine at Mount Sinai, New York, NY, USAAbstract: Oncolytic virotherapy on its own has numerous drawbacks, including an inability of the virus to actively target tumor cells and systemic toxicities at the high doses necessary to effectively treat tumors. Addition of immune cell-based carriers of oncolytic viruses holds promise as a technique in which oncolytic virus can be delivered directly to tumors in smaller and less toxic doses. Interestingly, the cell carriers themselves have also demonstrated antitumor effects, which can be augmented further by tailoring the appropriate oncolytic virus to the appropriate cell type. This review discusses the multiple factors that go into devising an effective, cell-based delivery system for oncolytic viruses.Keywords: oncolytic virus, cell carrier, immune cells, cancer therapy, myeloid-derived suppressor cells

Fuel Cell System for Transportation -- 2005 Cost Estimate

Energy Technology Data Exchange (ETDEWEB)

Wheeler, D.

2006-10-01

Independent review report of the methodology used by TIAX to estimate the cost of producing PEM fuel cells using 2005 cell stack technology. The U.S. Department of Energy (DOE) Hydrogen, Fuel Cells and Infrastructure Technologies Program Manager asked the National Renewable Energy Laboratory (NREL) to commission an independent review of the 2005 TIAX cost analysis for fuel cell production. The NREL Systems Integrator is responsible for conducting independent reviews of progress toward meeting the DOE Hydrogen Program (the Program) technical targets. An important technical target of the Program is the proton exchange membrane (PEM) fuel cell cost in terms of dollars per kilowatt ($/kW). The Program's Multi-Year Program Research, Development, and Demonstration Plan established $125/kW as the 2005 technical target. Over the last several years, the Program has contracted with TIAX, LLC (TIAX) to produce estimates of the high volume cost of PEM fuel cell production for transportation use. Since no manufacturer is yet producing PEM fuel cells in the quantities needed for an initial hydrogen-based transportation economy, these estimates are necessary for DOE to gauge progress toward meeting its targets. For a PEM fuel cell system configuration developed by Argonne National Laboratory, TIAX estimated the total cost to be $108/kW, based on assumptions of 500,000 units per year produced with 2005 cell stack technology, vertical integration of cell stack manufacturing, and balance-of-plant (BOP) components purchased from a supplier network. Furthermore, TIAX conducted a Monte Carlo analysis by varying ten key parameters over a wide range of values and estimated with 98% certainty that the mean PEM fuel cell system cost would be below DOE's 2005 target of $125/kW. NREL commissioned DJW TECHNOLOGY, LLC to form an Independent Review Team (the Team) of industry fuel cell experts and to evaluate the cost estimation process and the results reported by TIAX. The results of

Fuel cell-gas turbine hybrid system design part II: Dynamics and control

Science.gov (United States)

McLarty, Dustin; Brouwer, Jack; Samuelsen, Scott

2014-05-01

Fuel cell gas turbine hybrid systems have achieved ultra-high efficiency and ultra-low emissions at small scales, but have yet to demonstrate effective dynamic responsiveness or base-load cost savings. Fuel cell systems and hybrid prototypes have not utilized controls to address thermal cycling during load following operation, and have thus been relegated to the less valuable base-load and peak shaving power market. Additionally, pressurized hybrid topping cycles have exhibited increased stall/surge characteristics particularly during off-design operation. This paper evaluates additional control actuators with simple control methods capable of mitigating spatial temperature variation and stall/surge risk during load following operation of hybrid fuel cell systems. The novel use of detailed, spatially resolved, physical fuel cell and turbine models in an integrated system simulation enables the development and evaluation of these additional control methods. It is shown that the hybrid system can achieve greater dynamic response over a larger operating envelope than either individual sub-system; the fuel cell or gas turbine. Results indicate that a combined feed-forward, P-I and cascade control strategy is capable of handling moderate perturbations and achieving a 2:1 (MCFC) or 4:1 (SOFC) turndown ratio while retaining >65% fuel-to-electricity efficiency, while maintaining an acceptable stack temperature profile and stall/surge margin.

Impedance sensor technology for cell-based assays in the framework of a high-content screening system

International Nuclear Information System (INIS)

Schwarzenberger, T; Wolf, P; Brischwein, M; Kleinhans, R; Demmel, F; Becker, B; Wolf, B; Lechner, A

2011-01-01

Living cultured cells react to external influences, such as pharmaceutical agents, in an intricate manner due to their complex internal signal processing. Impedance sensing of cells on microelectrodes is a favored label-free technology to indicate cellular events, usually ascribed to morphologic alteration or changes in cellular adhesion, which is usually found in stand-alone systems that do not incorporate life support or additional sensor systems. However, only in symbiosis with metabolic activity sensing and picture documentation may a complete insight into cellular vitality be provided. This complement was created within the framework of an automated high-content screening system previously developed by our group, monitoring 24 cell culture chambers in parallel. The objective of this paper is the development of miniaturized electronics for impedance measurements and its system integration as a modular unit. In addition, it is shown how sensor electrodes were optimized by impedance matching such that spectroscopy and raw data analysis become feasible for every culture well. Undesired mechanical stress on cultured cells may arise from the medium and agent support system of the autonomous screening apparatus. This paper demonstrates how this hazard is treated with the simulation of microfluidics and impedance measurements. Physiological data are subsequently derived from the exemplary tumor cell line MCF-7 both during treatment with the agent doxorubicin and through the impact of natural killer cells. This correlates the information content of complex impedance spectra with cellular respiration as well as data from microscopy

Multifunctional, chitosan-based nano therapeutics: design and application for two- and three-dimensional cell culture systems

Science.gov (United States)

Suarato, Giulia

There is a constant demand for sensitive and effective anti-cancer drug delivery systems, capable of detecting early-stage pathological conditions and increasing patient survival. Recently, chitosan-based drug delivery nanocomplexes have shown to smartly respond to the distinctive features of the tumor microenvironment, a complex network of extracellular molecules, stromal and endothelial cells, which supports the tumor formation and its metastatic invasion. Due to biocompatibility, easy chemical tailorability, and pH-responsiveness, chitosan has emerged as a promising candidate for the formulation of supramolecular multifunctional materials. The present study focuses on the design, fabrication and characterization of fluorescently labelled, hydrophobically modified glycol chitosan nano-micelles (HGC NPs), suitably tailored for the delivery of anti-neoplastic compounds to various tumor models. Doxorubicin-loaded HGC NPs have been delivered to a bone cancer model, both in monolayer and in 3D spheroid configuration, to assess for differences in the delivery profiles and in the therapeutic efficacy. Compared to the free drug, nanocomplexes showed rapid uptake and a more homogeneous distribution in 3D spheroids, a powerful cellular tool which recapitulates some of the in vivo tumor microenvironment features. In a second part of this thesis work, with the purpose of designing an active targeting tumor-homing nano-therapeutic system, HGC NPs have been linked, via avidin-biotin interaction, with a IVS4 peptide, a small molecule with inhibitory activity on MMP-14-mediated functions. An extensive study conducted on triple negative breast cancer cells in monolayer revealed the MMP-14-IVS4-HGC association at the cancer cell membrane, the preferential uptake, and the consequent impairment of protease-associated migratory ability. As an additional application of our engineered construct, HGC micelles have been decorated with a liver kinase B1 (LKB1), a critical kinase involved

Fabrication and Characterization of Copper System Compound Semiconductor Solar Cells

Directory of Open Access Journals (Sweden)

Ryosuke Motoyoshi

2010-01-01

Full Text Available Copper system compound semiconductor solar cells were produced by a spin-coating method, and their cell performance and structures were investigated. Copper indium disulfide- (CIS- based solar cells with titanium dioxide (TiO2 were produced on F-doped SnO2 (FTO. A device based on an FTO/CIS/TiO2 structure provided better cell performance compared to that based on FTO/TiO2/CIS structure. Cupric oxide- (CuO- and cuprous oxide- (Cu2O- based solar cells with fullerene (C60 were also fabricated on FTO and indium tin oxide (ITO. The microstructure and cell performance of the CuO/C60 heterojunction and the Cu2O:C60 bulk heterojunction structure were investigated. The photovoltaic devices based on FTO/CuO/C60 and ITO/Cu2O:C60 structures provided short-circuit current density of 0.015 mAcm−2 and 0.11 mAcm−2, and open-circuit voltage of 0.045 V and 0.17 V under an Air Mass 1.5 illumination, respectively. The microstructures of the active layers were examined by X-ray diffraction and transmission electron microscopy.

Optimization of Fuel Cell System Operating Conditions for Fuel Cell Vehicles

OpenAIRE

Zhao, Hengbing; Burke, Andy

2008-01-01

Proton Exchange Membrane fuel cell (PEMFC) technology for use in fuel cell vehicles and other applications has been intensively developed in recent decades. Besides the fuel cell stack, air and fuel control and thermal and water management are major challenges in the development of the fuel cell for vehicle applications. The air supply system can have a major impact on overall system efficiency. In this paper a fuel cell system model for optimizing system operating conditions was developed wh...

Efficient expansion of mesenchymal stromal cells in a disposable fixed bed culture system.

Science.gov (United States)

Mizukami, Amanda; Orellana, Maristela D; Caruso, Sâmia R; de Lima Prata, Karen; Covas, Dimas T; Swiech, Kamilla

2013-01-01

The need for efficient and reliable technologies for clinical-scale expansion of mesenchymal stromal cells (MSC) has led to the use of disposable bioreactors and culture systems. Here, we evaluate the expansion of cord blood-derived MSC in a disposable fixed bed culture system. Starting from an initial cell density of 6.0 × 10(7) cells, after 7 days of culture, it was possible to produce of 4.2(±0.8) × 10(8) cells, which represents a fold increase of 7.0 (±1.4). After enzymatic retrieval from Fibra-Cell disks, the cells were able to maintain their potential for differentiation into adipocytes and osteocytes and were positive for many markers common to MSC (CD73, CD90, and CD105). The results obtained in this study demonstrate that MSC can be efficiently expanded in the culture system. This novel approach presents several advantages over the current expansion systems, based on culture flasks or microcarrier-based spinner flasks and represents a key element for MSC cellular therapy according to GMP compliant clinical-scale production system. Copyright © 2013 American Institute of Chemical Engineers.

Culture media-based selection of endothelial cells, pericytes, and perivascular-resident macrophage-like melanocytes from the young mouse vestibular system.

Science.gov (United States)

Zhang, Jinhui; Chen, Songlin; Cai, Jing; Hou, Zhiqiang; Wang, Xiaohan; Kachelmeier, Allan; Shi, Xiaorui

2017-03-01

The vestibular blood-labyrinth barrier (BLB) is comprised of perivascular-resident macrophage-like melanocytes (PVM/Ms) and pericytes (PCs), in addition to endothelial cells (ECs) and basement membrane (BM), and bears strong resemblance to the cochlear BLB in the stria vascularis. Over the past few decades, in vitro cell-based models have been widely used in blood-brain barrier (BBB) and blood-retina barrier (BRB) research, and have proved to be powerful tools for studying cell-cell interactions in their respective organs. Study of both the vestibular and strial BLB has been limited by the unavailability of primary culture cells from these barriers. To better understand how barrier component cells interact in the vestibular system to control BLB function, we developed a novel culture medium-based method for obtaining EC, PC, and PVM/M primary cells from tiny explants of the semicircular canal, sacculus, utriculus, and ampullae tissue of young mouse ears at post-natal age 8-12 d. Each phenotype is grown in a specific culture medium which selectively supports the phenotype in a mixed population of vestibular cell types. The unwanted phenotypes do not survive passaging. The protocol does not require additional equipment or special enzyme treatment. The harvesting process takes less than 2 h. Primary cell types are generated within 7-10 d. The primary culture ECs, PCs, and PVM/M shave consistent phenotypes more than 90% pure after two passages (∼ 3 weeks). The highly purified primary cell lines can be used for studying cell-cell interactions, barrier permeability, and angiogenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

Increasing the sensitivity for stem cell monitoring in system-function based magnetic particle imaging

International Nuclear Information System (INIS)

Them, Kolja; Szwargulski, P; Knopp, Tobias; Salamon, J; Kaul, M G; Ittrich, H; Sequeira, S; Lange, C

2016-01-01

The use of superparamagnetic iron oxide nanoparticles (SPIONs) has provided new possibilities in biophysics and biomedical imaging technologies. The magnetization dynamics of SPIONs, which can be influenced by the environment, are of central interest. In this work, different biological SPION environments are used to investigate three different calibration methods for stem cell monitoring in magnetic particle imaging. It is shown that calibrating using SPIONs immobilized via agarose gel or intracellular uptake results in superior stem cell image quality compared to mobile SPIONs in saline. This superior image quality enables more sensitive localization and identification of a significantly smaller number of magnetically labeled stem cells. The results are important for cell tracking and monitoring of future SPION based therapies such as hyperthermia based cancer therapies, targeted drug delivery, or tissue regeneration approaches where it is crucial to image a sufficiently small number of SPIONs interacting with biological matter. (paper)

Arrangement of fuel cell system for TNRF

International Nuclear Information System (INIS)

Nojima, Takehiro; Yasuda, Ryo; Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito; Takenaka, Nobuyuki; Hayashida, Hirotoshi

2012-02-01

Polymer electrolyte fuel cells (fuel cells) can be potentially employed as sources of clean energy because they discharge only water as by-products. Fuel cells generate electricity with supply of oxygen and hydrogen gases. However, the water produced by the fuel cells blocks the gas supply, thereby degrading their performances. Therefore, it is important to understand the behavior of the water produced by the fuel cells in order to facilitate their development. Neutron radiography is a useful tool for visualizing the distribution of water in fuel cells. We have designed fuel cell operation system for TNRF (Thermal Neutron Radiography Facility) at JRR-3. The fuel cell operation system consists of various components such as gas flow and humidification systems, hydrogen-diluting system, purge system, and safety system for hydrogen gas. We tested this system using a Japan Automobile Research Institute (JARI) standard cell. The system performed stably and efficiently. In addition, neutron radiography tests were carried out to visualize the water distribution. The water produced by the fuel cell was observed during the fuel cell operation. (author)

Optimal/flatness based-control of stand-alone power systems using fuel cells, batteries and supercapacitors

Directory of Open Access Journals (Sweden)

Mahdi Benaouadj

2017-03-01

Full Text Available In this work, an optimal control (under constraints based on the Pontryagin’s maximum principle is used to optimally manage energy flows in a basic PEM (Proton Exchange Membrane fuel cells system associated to lithium-ion batteries and supercapacitors through a common DC bus having a voltage to stabilize using the differential flatness approach. The adaptation of voltage levels between different sources and load is ensured by use of three DCDC converters, one boost connected to the PEM fuel cells, while the two others are buck/boost and connected to the lithium-ion batteries and supercapacitors. The aim of this paper is to develop an energy management strategy that is able to satisfy the following objectives: - Impose the power requested by a habitat (representing the load according to a proposed daily consumption profile, - Keep fuel cells working at optimal power delivery conditions, - Maintain constant voltage across the common DC bus, - Stabilize the batteries voltage and stored quantity of charge at desired values given by the optimal control. Results obtained under MATLAB/Simulink environment prove that the cited objectives are satisfied, validating then, effectiveness and complementarity between the optimal and flatness concepts proposed for energy management. Note that this study is currently in experimentally validation within MSE Laboratory.

Validation of shortened 2-day sterility testing of mesenchymal stem cell-based therapeutic preparation on an automated culture system.

Science.gov (United States)

Lysák, Daniel; Holubová, Monika; Bergerová, Tamara; Vávrová, Monika; Cangemi, Giuseppina Cristina; Ciccocioppo, Rachele; Kruzliak, Peter; Jindra, Pavel

2016-03-01

Cell therapy products represent a new trend of treatment in the field of immunotherapy and regenerative medicine. Their biological nature and multistep preparation procedure require the application of complex release criteria and quality control. Microbial contamination of cell therapy products is a potential source of morbidity in recipients. The automated blood culture systems are widely used for the detection of microorganisms in cell therapy products. However the standard 2-week cultivation period is too long for some cell-based treatments and alternative methods have to be devised. We tried to verify whether a shortened cultivation of the supernatant from the mesenchymal stem cell (MSC) culture obtained 2 days before the cell harvest could sufficiently detect microbial growth and allow the release of MSC for clinical application. We compared the standard Ph. Eur. cultivation method and the automated blood culture system BACTEC (Becton Dickinson). The time to detection (TTD) and the detection limit were analyzed for three bacterial and two fungal strains. The Staphylococcus aureus and Pseudomonas aeruginosa were recognized within 24 h with both methods (detection limit ~10 CFU). The time required for the detection of Bacillus subtilis was shorter with the automated method (TTD 10.3 vs. 60 h for 10-100 CFU). The BACTEC system reached significantly shorter times to the detection of Candida albicans and Aspergillus brasiliensis growth compared to the classical method (15.5 vs. 48 and 31.5 vs. 48 h, respectively; 10-100 CFU). The positivity was demonstrated within 48 h in all bottles, regardless of the size of the inoculum. This study validated the automated cultivation system as a method able to detect all tested microorganisms within a 48-h period with a detection limit of ~10 CFU. Only in case of B. subtilis, the lowest inoculum (~10 CFU) was not recognized. The 2-day cultivation technique is then capable of confirming the microbiological safety of MSC and

Systematic reconstruction of TRANSPATH data into cell system markup language.

Science.gov (United States)

Nagasaki, Masao; Saito, Ayumu; Li, Chen; Jeong, Euna; Miyano, Satoru

2008-06-23

Many biological repositories store information based on experimental study of the biological processes within a cell, such as protein-protein interactions, metabolic pathways, signal transduction pathways, or regulations of transcription factors and miRNA. Unfortunately, it is difficult to directly use such information when generating simulation-based models. Thus, modeling rules for encoding biological knowledge into system-dynamics-oriented standardized formats would be very useful for fully understanding cellular dynamics at the system level. We selected the TRANSPATH database, a manually curated high-quality pathway database, which provides a plentiful source of cellular events in humans, mice, and rats, collected from over 31,500 publications. In this work, we have developed 16 modeling rules based on hybrid functional Petri net with extension (HFPNe), which is suitable for graphical representing and simulating biological processes. In the modeling rules, each Petri net element is incorporated with Cell System Ontology to enable semantic interoperability of models. As a formal ontology for biological pathway modeling with dynamics, CSO also defines biological terminology and corresponding icons. By combining HFPNe with the CSO features, it is possible to make TRANSPATH data to simulation-based and semantically valid models. The results are encoded into a biological pathway format, Cell System Markup Language (CSML), which eases the exchange and integration of biological data and models. By using the 16 modeling rules, 97% of the reactions in TRANSPATH are converted into simulation-based models represented in CSML. This reconstruction demonstrates that it is possible to use our rules to generate quantitative models from static pathway descriptions.

A Small-Molecule Screen for Enhanced Homing of Systemically Infused Cells

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Oren Levy

2015-03-01

Full Text Available Poor homing of systemically infused cells to disease sites may limit the success of exogenous cell-based therapy. In this study, we screened 9,000 signal-transduction modulators to identify hits that increase mesenchymal stromal cell (MSC surface expression of homing ligands that bind to intercellular adhesion molecule 1 (ICAM-1, such as CD11a. Pretreatment of MSCs with Ro-31-8425, an identified hit from this screen, increased MSC firm adhesion to an ICAM-1-coated substrate in vitro and enabled targeted delivery of systemically administered MSCs to inflamed sites in vivo in a CD11a- (and other ICAM-1-binding domains-dependent manner. This resulted in a heightened anti-inflammatory response. This represents a new strategy for engineering cell homing to enhance therapeutic efficacy and validates CD11a and ICAM-1 as potential targets. Altogether, this multi-step screening process may significantly improve clinical outcomes of cell-based therapies.

Performance evaluation and parametric optimum design of a molten carbonate fuel cell-thermophotovoltaic cell hybrid system

International Nuclear Information System (INIS)

Yang, Zhimin; Liao, Tianjun; Zhou, Yinghui; Lin, Guoxing; Chen, Jincan

2016-01-01

Highlights: • A molten carbonate fuel cell-thermophotovoltaic cell hybrid system is established. • The performance characteristics of the hybrid system are systematically evaluated. • The optimal regions of the power output density and efficiency are determined. • The values of key parameters at the maximum power output density are calculated. • The proposed system is proved to have advantages over other hybrid systems. - Abstract: A new model of the hybrid system composed of a molten carbonate fuel cell (MCFC) and a thermophotovoltaic cell (TPVC) is proposed to recovery the waste heat produced by the MCFC. Expressions for the power output and the efficiency of the hybrid system are analytically derived. The performance characteristics of the hybrid system are evaluated. It is found that when the current density of the MCFC, voltage output of the TPVC, electrode area ratio of the MCFC to the TPVC, and energy gap of the material in the photovoltaic cell are optimally chosen, the maximum power output density of the hybrid system is obviously larger than that of the single MCFC. Moreover, the improved percentages of the maximum power output density of the proposed model relative to that of the single MCFC are calculated for differently operating temperatures of the MCFC and are compared with those of some MCFC-based hybrid systems reported in the literature, and consequently, the advantages of the MCFC-TPVC hybrid system are revealed.

Automotive Fuel Processor Development and Demonstration with Fuel Cell Systems

Energy Technology Data Exchange (ETDEWEB)

Nuvera Fuel Cells

2005-04-15

processor subsystems (fuel reformer, CO cleanup, and exhaust cleanup) that were small enough to integrate on a vehicle and (2) evaluating the fuel processor system performance for hydrogen production, efficiency, thermal integration, startup, durability and ability to integrate with fuel cells. Nuvera carried out a three-part development program that created multi-fuel (gasoline, ethanol, natural gas) fuel processing systems and investigated integration of fuel cell / fuel processor systems. The targets for the various stages of development were initially based on the goals of the DOE's Partnership for New Generation Vehicles (PNGV) initiative and later on the Freedom Car goals. The three parts are summarized below with the names based on the topic numbers from the original Solicitation for Financial Assistance Award (SFAA).

Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

Energy Technology Data Exchange (ETDEWEB)

Faress Rahman; Nguyen Minh

2004-01-04

This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the July 2003 to December 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. Also, another activity included in this program focuses on the development of SOFC scale up strategies.

Aircraft Fuel Cell Power Systems

Science.gov (United States)

Needham, Robert

2004-01-01

In recent years, fuel cells have been explored for use in aircraft. While the weight and size of fuel cells allows only the smallest of aircraft to use fuel cells for their primary engines, fuel cells have showed promise for use as auxiliary power units (APUs), which power aircraft accessories and serve as an electrical backup in case of an engine failure. Fuel cell MUS are both more efficient and emit fewer pollutants. However, sea-level fuel cells need modifications to be properly used in aircraft applications. At high altitudes, the ambient air has a much lower pressure than at sea level, which makes it much more difficult to get air into the fuel cell to react and produce electricity. Compressors can be used to pressurize the air, but this leads to added weight, volume, and power usage, all of which are undesirable things. Another problem is that fuel cells require hydrogen to create electricity, and ever since the Hindenburg burst into flames, aircraft carrying large quantities of hydrogen have not been in high demand. However, jet fuel is a hydrocarbon, so it is possible to reform it into hydrogen. Since jet fuel is already used to power conventional APUs, it is very convenient to use this to generate the hydrogen for fuel-cell-based APUs. Fuel cells also tend to get large and heavy when used for applications that require a large amount of power. Reducing the size and weight becomes especially beneficial when it comes to fuel cells for aircraft. My goal this summer is to work on several aspects of Aircraft Fuel Cell Power System project. My first goal is to perform checks on a newly built injector rig designed to test different catalysts to determine the best setup for reforming Jet-A fuel into hydrogen. These checks include testing various thermocouples, transmitters, and transducers, as well making sure that the rig was actually built to the design specifications. These checks will help to ensure that the rig will operate properly and give correct results

On-line experimental validation of a model-based diagnostic algorithm dedicated to a solid oxide fuel cell system

Science.gov (United States)

Polverino, Pierpaolo; Esposito, Angelo; Pianese, Cesare; Ludwig, Bastian; Iwanschitz, Boris; Mai, Andreas

2016-02-01

In the current energetic scenario, Solid Oxide Fuel Cells (SOFCs) exhibit appealing features which make them suitable for environmental-friendly power production, especially for stationary applications. An example is represented by micro-combined heat and power (μ-CHP) generation units based on SOFC stacks, which are able to produce electric and thermal power with high efficiency and low pollutant and greenhouse gases emissions. However, the main limitations to their diffusion into the mass market consist in high maintenance and production costs and short lifetime. To improve these aspects, the current research activity focuses on the development of robust and generalizable diagnostic techniques, aimed at detecting and isolating faults within the entire system (i.e. SOFC stack and balance of plant). Coupled with appropriate recovery strategies, diagnosis can prevent undesired system shutdowns during faulty conditions, with consequent lifetime increase and maintenance costs reduction. This paper deals with the on-line experimental validation of a model-based diagnostic algorithm applied to a pre-commercial SOFC system. The proposed algorithm exploits a Fault Signature Matrix based on a Fault Tree Analysis and improved through fault simulations. The algorithm is characterized on the considered system and it is validated by means of experimental induction of faulty states in controlled conditions.

An episomal vector-based CRISPR/Cas9 system for highly efficient gene knockout in human pluripotent stem cells.

Science.gov (United States)

Xie, Yifang; Wang, Daqi; Lan, Feng; Wei, Gang; Ni, Ting; Chai, Renjie; Liu, Dong; Hu, Shijun; Li, Mingqing; Li, Dajin; Wang, Hongyan; Wang, Yongming

2017-05-24

Human pluripotent stem cells (hPSCs) represent a unique opportunity for understanding the molecular mechanisms underlying complex traits and diseases. CRISPR/Cas9 is a powerful tool to introduce genetic mutations into the hPSCs for loss-of-function studies. Here, we developed an episomal vector-based CRISPR/Cas9 system, which we called epiCRISPR, for highly efficient gene knockout in hPSCs. The epiCRISPR system enables generation of up to 100% Insertion/Deletion (indel) rates. In addition, the epiCRISPR system enables efficient double-gene knockout and genomic deletion. To minimize off-target cleavage, we combined the episomal vector technology with double-nicking strategy and recent developed high fidelity Cas9. Thus the epiCRISPR system offers a highly efficient platform for genetic analysis in hPSCs.

Coal Integrated Gasification Fuel Cell System Study

Energy Technology Data Exchange (ETDEWEB)

Chellappa Balan; Debashis Dey; Sukru-Alper Eker; Max Peter; Pavel Sokolov; Greg Wotzak

2004-01-31

This study analyzes the performance and economics of power generation systems based on Solid Oxide Fuel Cell (SOFC) technology and fueled by gasified coal. System concepts that integrate a coal gasifier with a SOFC, a gas turbine, and a steam turbine were developed and analyzed for plant sizes in excess of 200 MW. Two alternative integration configurations were selected with projected system efficiency of over 53% on a HHV basis, or about 10 percentage points higher than that of the state-of-the-art Integrated Gasification Combined Cycle (IGCC) systems. The initial cost of both selected configurations was found to be comparable with the IGCC system costs at approximately $1700/kW. An absorption-based CO2 isolation scheme was developed, and its penalty on the system performance and cost was estimated to be less approximately 2.7% and $370/kW. Technology gaps and required engineering development efforts were identified and evaluated.

System level modeling and component level control of fuel cells

Science.gov (United States)

Xue, Xingjian

This dissertation investigates the fuel cell systems and the related technologies in three aspects: (1) system-level dynamic modeling of both PEM fuel cell (PEMFC) and solid oxide fuel cell (SOFC); (2) condition monitoring scheme development of PEM fuel cell system using model-based statistical method; and (3) strategy and algorithm development of precision control with potential application in energy systems. The dissertation first presents a system level dynamic modeling strategy for PEM fuel cells. It is well known that water plays a critical role in PEM fuel cell operations. It makes the membrane function appropriately and improves the durability. The low temperature operating conditions, however, impose modeling difficulties in characterizing the liquid-vapor two phase change phenomenon, which becomes even more complex under dynamic operating conditions. This dissertation proposes an innovative method to characterize this phenomenon, and builds a comprehensive model for PEM fuel cell at the system level. The model features the complete characterization of multi-physics dynamic coupling effects with the inclusion of dynamic phase change. The model is validated using Ballard stack experimental result from open literature. The system behavior and the internal coupling effects are also investigated using this model under various operating conditions. Anode-supported tubular SOFC is also investigated in the dissertation. While the Nernst potential plays a central role in characterizing the electrochemical performance, the traditional Nernst equation may lead to incorrect analysis results under dynamic operating conditions due to the current reverse flow phenomenon. This dissertation presents a systematic study in this regard to incorporate a modified Nernst potential expression and the heat/mass transfer into the analysis. The model is used to investigate the limitations and optimal results of various operating conditions; it can also be utilized to perform the

Standard cell-based implementation of a digital optoelectronic neural-network hardware.

Science.gov (United States)

Maier, K D; Beckstein, C; Blickhan, R; Erhard, W

2001-03-10

A standard cell-based implementation of a digital optoelectronic neural-network architecture is presented. The overall structure of the multilayer perceptron network that was used, the optoelectronic interconnection system between the layers, and all components required in each layer are defined. The design process from VHDL-based modeling from synthesis and partly automatic placing and routing to the final editing of one layer of the circuit of the multilayer perceptrons are described. A suitable approach for the standard cell-based design of optoelectronic systems is presented, and shortcomings of the design tool that was used are pointed out. The layout for the microelectronic circuit of one layer in a multilayer perceptron neural network with a performance potential 1 magnitude higher than neural networks that are purely electronic based has been successfully designed.

Aquaporin-4 autoantibodies in neuromyelitis optica spectrum disorders: comparison between tissue-based and cell-based indirect immunofluorescence assays

Directory of Open Access Journals (Sweden)

Chan Koon H

2010-09-01

Full Text Available Abstract Background Neuromyelitis optica spectrum disorders (NMOSD are severe central nervous system inflammatory demyelinating disorders (CNS IDD characterized by monophasic or relapsing, longitudinally extensive transverse myelitis (LETM and/or optic neuritis (ON. A significant proportion of NMOSD patients are seropositive for aquaporin-4 (AQP4 autoantibodies. We compared the AQP4 autoantibody detection rates of tissue-based indirect immunofluorescence assay (IIFA and cell-based IIFA. Methods Serum of Chinese CNS IDD patients were assayed for AQP4 autoantibodies by tissue-based IIFA using monkey cerebellum and cell-based IIFA using transfected HEK293 cells which express human AQP4 on their cell membranes. Results In total, 128 CNS IDD patients were studied. We found that 78% of NMO patients were seropositive for AQP4 autoantibodies by cell-based IIFA versus 61% by tissue-based IFA (p = 0.250, 75% of patients having relapsing myelitis (RM with LETM were seropositive by cell-based IIFA versus 50% by tissue-based IIFA (p = 0.250, and 33% of relapsing ON patients were seropositive by cell-based IIFA versus 22% by tissue-based IIFA (p = 1.000; however the differences were not statistically significant. All patients seropositive by tissue-based IIFA were also seropositive for AQP4 autoantibodies by cell-based IIFA. Among 29 NMOSD patients seropositive for AQP4 autoantibodies by cell-based IIFA, 20 (69% were seropositive by tissue-based IIFA. The 9 patients seropositive by cell-based IIFA while seronegative by tissue-based IIFA had NMO (3, RM with LETM (3, a single attack of LETM (1, relapsing ON (1 and a single ON attack (1. Among 23 NMO or RM patients seropositive for AQP4 autoantibodies by cell-based IIFA, comparison between those seropositive (n = 17 and seronegative (n = 6 by tissue-based IIFA revealed no differences in clinical and neuroradiological characteristics between the two groups. Conclusion Cell-based IIFA is slightly more sensitive

Bioanalytical system for detection of cancer cells with photoluminescent ZnO nanorods

Science.gov (United States)

Viter, R.; Jekabsons, K.; Kalnina, Z.; Poletaev, N.; Hsu, S. H.; Riekstina, U.

2016-11-01

Using photoluminescent ZnO nanorods and carbohydrate marker SSEA-4, a novel cancer cell recognition system was developed. Immobilization of SSEA-4 antibodies (αSSEA-4) on ZnO nanorods was performed in buffer solution (pH = 7.1) over 2 h. The cancer cell line probes were fixed on the glass slide. One hundred microliters of ZnO-αSSEA-4 conjugates were deposited on the cell probe and exposed for 30 min. After washing photoluminescence spectra were recorded. Based on the developed methodology, ZnO-αSSEA-4 probes were tested on patient-derived breast and colorectal carcinoma cells. Our data clearly show that the carbohydrate SSEA-4 molecule is expressed on cancer cell lines and patient-derived cancer cells. Moreover, SSEA-4 targeted ZnO nanorods bind to the patient-derived cancer cells with high selectivity and the photoluminescence signal increased tremendously compared to the signal from the control samples. Furthermore, the photoluminescence intensity increase correlated with the extent of malignancy in the target cell population. A novel portable bioanalytical system, based on optical ZnO nanorods and fiber optic detection system was developed. We propose that carbohydrate SSEA-4 specific ZnO nanorods could be used for the development of cancer diagnostic biosensors and for targeted therapy.

Stem cells engineering for cell-based therapy.

Science.gov (United States)

Taupin, Philippe

2007-09-01

Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

A quasi-direct methanol fuel cell system based on blend polymer membrane electrolytes

DEFF Research Database (Denmark)

Li, Qingfeng; Hjuler, Hans Aage; Hasiotis, C.

2002-01-01

, compared to less than 100 ppm CO for the Nafion-based technology at 80degrees C. The high CO tolerance makes it possible to use the reformed hydrogen directly from a simple methanol reformer without further CO removal. That both the fuel cell and the methanol reformer operate at temperatures around 200......On the basis of blend polymer electrolytes of polybenzimidazole and sulfonated polysulfone, a polymer electrolyte membrane fuel cell was developed with an operational temperature up to 200degrees C. Due to the high operational temperature, the fuel cell can tolerate 1.0-3.0 vol % CO in the fuel...

Gravisensing in single-celled systems

Science.gov (United States)

Braun, M.; Limbach, C.

Single-celled systems are favourable cell types for studying several aspects of gravisensing and gravitropic responses. Whether and how actin is involved in both processes in higher plant statocytes is still a matter of intensive debate. In single-celled and tip-growing characean rhizoids and protonemata, however, there is clear evidence that actin is a central keyplayer controlling polarized growth and the mechanisms of gravity sensing and growth reorientation. Both cell types exhibit a unique actin polymerization in the extending tip, strictly colocalized with the prominent ER-aggregate in the center of the Spitzenkoerper. The local accumulation of ADF and profilin in this central array suggest that actin polymerization is controlled by these actin-binding proteins, which can be regulated by calcium, pH and a variety of other parameters. Distinct actin filaments extend even into the outermost tip and form a dense meshwork in the apical and subapical region, before they become bundled by villin to form two populations of thick actin cables that generate rotational cytoplasmic streaming in the basal region. Actomyosin not only mediates the delivery of secretory vesicles to the growing tip and controls the incorporation pattern of cell wall material, but also coordinates the tip-focused distribution pattern of calcium channels in the apical membrane. They establish the tip-high calcium gradient, a prerequisite for exocytosis. Microgravity experiments have added much to our understanding that both cell types use an efficient actomyosin-based system to control and correct the position of their statoliths and to direct sedimenting statoliths to confined graviperception sites at the plasma membrane. Actin's involvement in the graviresponses is more indirect. The upward growth of negatively gravitropic protonemata was shown to be preceded by a statolith-induced relocalization the Ca2+-calcium gradient to the upper flank that does not occur in positively gravitropic

Establishment of a rabbit Oct4 promoter-based EGFP reporter system.

Directory of Open Access Journals (Sweden)

Longquan Quan

Full Text Available Rabbits are commonly used as laboratory animal models to investigate human diseases and phylogenetic development. However, pluripotent stem cells that contribute to germline transmission have yet to be established in rabbits. The transcription factor Oct4, also known as Pou5f1, is considered essential for the maintenance of the pluripotency of stem cells. Hence, pluripotent cells can be identified by monitoring Oct4 expression using a well-established Oct4 promoter-based reporter system. This study developed a rabbit Oct4 promoter-based enhanced green fluorescent protein (EGFP reporter system by transfecting pROP2-EGFP into rabbit fetal fibroblasts (RFFs. The transgenic RFFs were used as donor cells for somatic cell nuclear transfer (SCNT. The EGFP expression was detected in the blastocysts and genital ridges of SCNT fetuses. Fibroblasts and neural stem cells (NSCs were derived from the SCNT fetuses. EGFP was also reactivated in blastocysts after the second SCNT, and induced pluripotent stem cells (iPSCs were obtained after reprogramming using Yamanaka's factors. The results above indicated that a rabbit reporter system used to monitor the differentiating status of cells was successfully developed.

Peptide Logic Circuits Based on Chemoenzymatic Ligation for Programmable Cell Apoptosis.

Science.gov (United States)

Li, Yong; Sun, Sujuan; Fan, Lin; Hu, Shanfang; Huang, Yan; Zhang, Ke; Nie, Zhou; Yao, Shouzhou

2017-11-20

A novel and versatile peptide-based bio-logic system capable of regulating cell function is developed using sortase A (SrtA), a peptide ligation enzyme, as a generic processor. By modular peptide design, we demonstrate that mammalian cells apoptosis can be programmed by peptide-based logic operations, including binary and combination gates (AND, INHIBIT, OR, and AND-INHIBIT), and a complex sequential logic circuit (multi-input keypad lock). Moreover, a proof-of-concept peptide regulatory circuit was developed to analyze the expression profile of cell-secreted protein biomarkers and trigger cancer-cell-specific apoptosis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Software-Based Student Response Systems: An Interdisciplinary Initiative

Science.gov (United States)

Fischer, Carol M.; Hoffman, Michael S.; Casey, Nancy C.; Cox, Maureen P.

2015-01-01

Colleagues from information technology and three academic departments collaborated on an instructional technology initiative to employ student response systems in classes in mathematics, accounting and education. The instructors assessed the viability of using software-based systems to enable students to use their own devices (cell phones,…

Fluorescent multiplex cell flow systems and methods

KAUST Repository

Merzaban, Jasmeen

2017-06-01

Systems and methods are provided for simultaneously assaying cell adhesion or cell rolling for multiple cell specimens. One embodiment provides a system for assaying adhesion or cell rolling of multiple cell specimens that includes a confocal imaging system containing a parallel plate flow chamber, a pump in fluid communication with the parallel plate flow chamber via a flow chamber inlet line and a cell suspension in fluid communication with the parallel plate flow chamber via a flow chamber outlet line. The system also includes a laser scanning system in electronic communication with the confocal imaging system, and a computer in communication with the confocal imaging system and laser scanning system. In certain embodiments, the laser scanning system emits multiple electromagnetic wavelengths simultaneously it cause multiple fluorescent labels having different excitation wavelength maximums to fluoresce. The system can simultaneously capture real-time fluorescence images from at least seven cell specimens in the parallel plate flow chamber.

Lithium-thionyl chloride cell system safety hazard analysis

Science.gov (United States)

Dampier, F. W.

1985-03-01

This system safety analysis for the lithium thionyl chloride cell is a critical review of the technical literature pertaining to cell safety and draws conclusions and makes recommendations based on this data. The thermodynamics and kinetics of the electrochemical reactions occurring during discharge are discussed with particular attention given to unstable SOCl2 reduction intermediates. Potentially hazardous reactions between the various cell components and discharge products or impurities that could occur during electrical or thermal abuse are described and the most hazardous conditions and reactions identified. Design factors influencing the safety of Li/SOCl2 cells, shipping and disposal methods and the toxicity of Li/SOCl2 battery components are additional safety issues that are also addressed.

Tensegrity I. Cell structure and hierarchical systems biology

Science.gov (United States)

Ingber, Donald E.

2003-01-01

In 1993, a Commentary in this journal described how a simple mechanical model of cell structure based on tensegrity architecture can help to explain how cell shape, movement and cytoskeletal mechanics are controlled, as well as how cells sense and respond to mechanical forces (J. Cell Sci. 104, 613-627). The cellular tensegrity model can now be revisited and placed in context of new advances in our understanding of cell structure, biological networks and mechanoregulation that have been made over the past decade. Recent work provides strong evidence to support the use of tensegrity by cells, and mathematical formulations of the model predict many aspects of cell behavior. In addition, development of the tensegrity theory and its translation into mathematical terms are beginning to allow us to define the relationship between mechanics and biochemistry at the molecular level and to attack the larger problem of biological complexity. Part I of this two-part article covers the evidence for cellular tensegrity at the molecular level and describes how this building system may provide a structural basis for the hierarchical organization of living systems--from molecule to organism. Part II, which focuses on how these structural networks influence information processing networks, appears in the next issue.

Development and characterization of a green fluorescent protein-based rat cell bioassay system for detection of AH receptor ligands

Energy Technology Data Exchange (ETDEWEB)

Zhao Bin; Denison, M. [California Univ., Davis, CA (United States). Dept. of Environmental Toxicology

2004-09-15

Proper epidemiological, risk assessment and exposure analysis of TCDD and related HAHs requires accurate measurements of these chemicals both in the species of interest and in various exposure matrices (i.e. biological, environmental, food and feed). While high-resolution instrumental analysis techniques are established for these chemicals, these procedures are very costly, time-consuming and are impractical for large scale sampling studies. Accordingly, numerous bioanalytical methods have been developed for the detection of these chemicals in extracts from a variety of matrices, the majority of which take the advantage of the ability of these chemicals to activate one or more aspects of the AhR-dependent mechanism of action. One of the most sensitive bioassay systems developed to date is the so-called CALUX (Chemically Activated Luciferase Expression) assay, which is based on novel recombinant cell lines that contain a stably transfected dioxin (AhR)-responsive firefly luciferase gene. Treatment of these cells with TCDD and related HAHs and polycyclic aromatic hydrocarbons (PAHs), as well as other AhR ligands, results in induction of reporter gene expression in a time-, dose-, AhR-, and chemical-specific manner. The level of reporter gene expression correlates with the total concentration of the TCDD-like AhR inducers (agonists) present in the sample. Although the firefly luciferase reporter gene contributes to the high degree of sensitivity of the assay, it also has limitations with respect to our need for a rapid and inexpensive bioassay for high-throughput screening analysis. Accordingly, we previously developed a stably transfected murine cell line containing an AhRresponsive enhanced green fluorescent protein (EGFP) reporter gene. This cell line provided us with a high-throughput cell bioassay system for identification and characterization of AhR agonists and antagonists. Here we have extended these studies and describe the development, optimization, and

Modeling cell adhesion and proliferation: a cellular-automata based approach.

Science.gov (United States)

Vivas, J; Garzón-Alvarado, D; Cerrolaza, M

Cell adhesion is a process that involves the interaction between the cell membrane and another surface, either a cell or a substrate. Unlike experimental tests, computer models can simulate processes and study the result of experiments in a shorter time and lower costs. One of the tools used to simulate biological processes is the cellular automata, which is a dynamic system that is discrete both in space and time. This work describes a computer model based on cellular automata for the adhesion process and cell proliferation to predict the behavior of a cell population in suspension and adhered to a substrate. The values of the simulated system were obtained through experimental tests on fibroblast monolayer cultures. The results allow us to estimate the cells settling time in culture as well as the adhesion and proliferation time. The change in the cells morphology as the adhesion over the contact surface progress was also observed. The formation of the initial link between cell and the substrate of the adhesion was observed after 100 min where the cell on the substrate retains its spherical morphology during the simulation. The cellular automata model developed is, however, a simplified representation of the steps in the adhesion process and the subsequent proliferation. A combined framework of experimental and computational simulation based on cellular automata was proposed to represent the fibroblast adhesion on substrates and changes in a macro-scale observed in the cell during the adhesion process. The approach showed to be simple and efficient.

Solid-state, polymer-based fiber solar cells with carbon nanotube electrodes.

Science.gov (United States)

Liu, Dianyi; Zhao, Mingyan; Li, Yan; Bian, Zuqiang; Zhang, Luhui; Shang, Yuanyuan; Xia, Xinyuan; Zhang, Sen; Yun, Daqin; Liu, Zhiwei; Cao, Anyuan; Huang, Chunhui

2012-12-21

Most previous fiber-shaped solar cells were based on photoelectrochemical systems involving liquid electrolytes, which had issues such as device encapsulation and stability. Here, we deposited classical semiconducting polymer-based bulk heterojunction layers onto stainless steel wires to form primary electrodes and adopted carbon nanotube thin films or densified yarns to replace conventional metal counter electrodes. The polymer-based fiber cells with nanotube film or yarn electrodes showed power conversion efficiencies in the range 1.4% to 2.3%, with stable performance upon rotation and large-angle bending and during long-time storage without further encapsulation. Our fiber solar cells consisting of a polymeric active layer sandwiched between steel and carbon electrodes have potential in the manufacturing of low-cost, liquid-free, and flexible fiber-based photovoltaics.

Investigations on an advanced power system based on a high temperature polymer electrolyte membrane fuel cell and an organic Rankine cycle for heating and power production

International Nuclear Information System (INIS)

Perna, Alessandra; Minutillo, Mariagiovanna; Jannelli, Elio

2015-01-01

Energy systems based on fuel cells technology can have a strategic role in the range of small-size power generation for the sustainable energy development. In order to enhance their performance, it is possible to recover the “waste heat” from the fuel cells, for producing or thermal power (cogeneration systems) or further electric power by means of a bottoming power cycle (combined systems). In this work an advanced system based on the integration between a HT-PEMFC (high temperature polymer electrolyte membrane fuel cell) power unit and an ORC (organic Rankine cycle) plant, has been proposed and analysed as suitable energy power plant for supplying electric and thermal energies to a stand-alone residential utility. The system can operate both as cogeneration system, in which the electric and thermal loads are satisfied by the HT-PEMFC power unit and as electric generation system, in which the low temperature heat recovered from the fuel cells is used as energy source in the ORC plant for increasing the electric power production. A numerical model, able to characterize the behavior and to predict the performance of the HT-PEMFC/ORC system under different working conditions, has been developed by using the AspenPlus™ code. - Highlights: • The advanced plant can operate both as CHP system and as electric generation system. • The performance prediction of the integrated system is carried out by numerical modeling. • ORC thermodynamic optimization is carried out by a sensitivity analysis. • Thermal coupling between the HT-PEMC system and the ORC plant is analyzed. • Results are very promising in the field of the distributed generation

Incubator embedded cell culture imaging system (EmSight) based on Fourier ptychographic microscopy.

Science.gov (United States)

Kim, Jinho; Henley, Beverley M; Kim, Charlene H; Lester, Henry A; Yang, Changhuei

2016-08-01

Multi-day tracking of cells in culture systems can provide valuable information in bioscience experiments. We report the development of a cell culture imaging system, named EmSight, which incorporates multiple compact Fourier ptychographic microscopes with a standard multiwell imaging plate. The system is housed in an incubator and presently incorporates six microscopes. By using the same low magnification objective lenses as the objective and the tube lens, the EmSight is configured as a 1:1 imaging system that, providing large field-of-view (FOV) imaging onto a low-cost CMOS imaging sensor. The EmSight improves the image resolution by capturing a series of images of the sample at varying illumination angles; the instrument reconstructs a higher-resolution image by using the iterative Fourier ptychographic algorithm. In addition to providing high-resolution brightfield and phase imaging, the EmSight is also capable of fluorescence imaging at the native resolution of the objectives. We characterized the system using a phase Siemens star target, and show four-fold improved coherent resolution (synthetic NA of 0.42) and a depth of field of 0.2 mm. To conduct live, long-term dopaminergic neuron imaging, we cultured ventral midbrain from mice driving eGFP from the tyrosine hydroxylase promoter. The EmSight system tracks movements of dopaminergic neurons over a 21 day period.

Hybrid electric system based on fuel cell and battery and integrating a single dc/dc converter for a tramway

International Nuclear Information System (INIS)

Fernandez, Luis M.; Garcia, Pablo; Garcia, Carlos Andres; Jurado, Francisco

2011-01-01

Research highlights: → Hybrid electric power system for a real surface tramway. → Hybrid system based on PEM fuel cell with dc/dc converter and Ni-MH battery. → New control strategy for the energy management of the tramway. → Hybrid system demonstrated to meet appropriate driving cycle of the tramway. -- Abstract: This paper presents a hybrid electric power system for a real surface tramway. The hybrid system consists of two electrical energy sources integrating a single dc/dc converter to provide the power demanded by the tramway loads (four electric traction motors and auxiliary services): (1) a Polymer Electrolyte Membrane (PEM) fuel cell (FC) as the primary and (2) a rechargeable Ni-MH battery as electrical energy storage to supplement the FC over the driving cycle. According to the requirements of the real driving cycle of the tramway, it was considered a 200 kW PEM FC system with two FCs connected in parallel and a 34 Ah Ni-MH battery. The PEM FC and Ni-MH battery models were designed from commercially available components. The power conditioning system provides the appropriate power for the tramway. It is composed of: (1) a unique dc/dc boot converter which adapts the FC output voltage to the 750 V traction standard dc bus; (2) three phase inverters to drive properly each electric motors; and (3) a braking chopper to dissipate excess of regenerative braking energy. Suitable state machine control architecture is presented for the hybrid system, its objective being to provide demanded power by the driving cycle, optimizing the energy generated. Following this objective, a new state machine control strategy based on eight states decides the operating point of each component of the system and a cascade control structure allows achieving the operating points determined by the strategy. Simulation results of the real driving cycle of the tramway check the adequacy of the hybrid electric power system.

Hybrid electric system based on fuel cell and battery and integrating a single dc/dc converter for a tramway

Energy Technology Data Exchange (ETDEWEB)

Fernandez, Luis M., E-mail: luis.fernandez@uca.e [Department of Electrical Engineering, EPS Algeciras, University of Cadiz, Avda. Ramon Puyol, s/n. 11202 Algeciras (Cadiz) (Spain); Garcia, Pablo, E-mail: pablo.garcia@uca.e [Department of Electrical Engineering, EPS Algeciras, University of Cadiz, Avda. Ramon Puyol, s/n. 11202 Algeciras (Cadiz) (Spain); Garcia, Carlos Andres, E-mail: carlosandres.garcia@uca.e [Department of Electrical Engineering, EPS Algeciras, University of Cadiz, Avda. Ramon Puyol, s/n. 11202 Algeciras (Cadiz) (Spain); Jurado, Francisco, E-mail: fjurado@ujaen.e [Department of Electrical Engineering, EPS Linares, University of Jaen, C/Alfonso X, No. 28. 23700 Linares (Jaen) (Spain)

2011-05-15

Research highlights: {yields} Hybrid electric power system for a real surface tramway. {yields} Hybrid system based on PEM fuel cell with dc/dc converter and Ni-MH battery. {yields} New control strategy for the energy management of the tramway. {yields} Hybrid system demonstrated to meet appropriate driving cycle of the tramway. -- Abstract: This paper presents a hybrid electric power system for a real surface tramway. The hybrid system consists of two electrical energy sources integrating a single dc/dc converter to provide the power demanded by the tramway loads (four electric traction motors and auxiliary services): (1) a Polymer Electrolyte Membrane (PEM) fuel cell (FC) as the primary and (2) a rechargeable Ni-MH battery as electrical energy storage to supplement the FC over the driving cycle. According to the requirements of the real driving cycle of the tramway, it was considered a 200 kW PEM FC system with two FCs connected in parallel and a 34 Ah Ni-MH battery. The PEM FC and Ni-MH battery models were designed from commercially available components. The power conditioning system provides the appropriate power for the tramway. It is composed of: (1) a unique dc/dc boot converter which adapts the FC output voltage to the 750 V traction standard dc bus; (2) three phase inverters to drive properly each electric motors; and (3) a braking chopper to dissipate excess of regenerative braking energy. Suitable state machine control architecture is presented for the hybrid system, its objective being to provide demanded power by the driving cycle, optimizing the energy generated. Following this objective, a new state machine control strategy based on eight states decides the operating point of each component of the system and a cascade control structure allows achieving the operating points determined by the strategy. Simulation results of the real driving cycle of the tramway check the adequacy of the hybrid electric power system.

Fuel cell system with interconnect

Science.gov (United States)

Goettler, Richard; Liu, Zhien

2017-12-12

The present invention includes a fuel cell system having a plurality of adjacent electrochemical cells formed of an anode layer, a cathode layer spaced apart from the anode layer, and an electrolyte layer disposed between the anode layer and the cathode layer. The fuel cell system also includes at least one interconnect, the interconnect being structured to conduct free electrons between adjacent electrochemical cells. Each interconnect includes a primary conductor embedded within the electrolyte layer and structured to conduct the free electrons.

CCR6+ Th cell distribution differentiates systemic lupus erythematosus patients based on anti-dsDNA antibody status.

Science.gov (United States)

Zhong, Wei; Jiang, Zhenyu; Wu, Jiang; Jiang, Yanfang; Zhao, Ling

2018-01-01

Systemic lupus erythematosus (SLE) disease has been shown to be associated with the generation of multiple auto-antibodies. Among these, anti-dsDNA antibodies (anti-DNAs) are specific and play a pathogenic role in SLE. Indeed, anti-DNA + SLE patients display a worse disease course. The generation of these pathogenic anti-DNAs has been attributed to the interaction between aberrant T helper (Th) cells and autoimmune B cells. Thus, in this study we have investigated whether CCR6 + Th cells have the ability to differentiate SLE patients based on anti-DNA status, and if their distribution has any correlation with disease activity. We recruited 25 anti-DNA + and 25 anti-DNA - treatment-naive onset SLE patients, matched for various clinical characteristics in our nested matched case-control study. CCR6 + Th cells and their additional subsets were analyzed in each patient by flow cytometry. Anti-DNA + SLE patients specifically had a higher percentage of Th cells expressing CCR6 and CXCR3. Further analysis of CCR6 + Th cell subsets showed that anti-DNA + SLE patients had elevated proportions of Th9, Th17, Th17.1 and CCR4/CXCR3 double-negative (DN) cells. However, the proportions of CCR6 - Th subsets, including Th1 and Th2 cells, did not show any association with anti-DNA status. Finally, we identified a correlation between CCR6 + Th subsets and clinical indicators, specifically in anti-DNA + SLE patients. Our data indicated that CCR6 + Th cells and their subsets were elevated and correlated with disease activity in anti-DNA + SLE patients. We speculated that CCR6 + Th cells may contribute to distinct disease severity in anti-DNA + SLE patients.

A comprehensive review of PBI-based high temperature PEM fuel cells

DEFF Research Database (Denmark)

Simon Araya, Samuel; Zhou, Fan; Liso, Vincenzo

2016-01-01

of their design and characterization techniques at single cell, stack and system levels is given. The state-of-the-art concepts of different degradation mechanisms and methods of their mitigation are also discussed. Moreover, accelerated stress testing (AST) procedures for HT-PEMFCs available in literature...... fuel cell faults for targeted interventions based on the observed conditions to prevent sudden failures and to prolong the fuel cell's lifetime. However, the technology is still under development and robust on-line diagnostics tools are hardly available. Currently, mitigation is mainly done based......The current status on the understanding of the various operational aspects of high temperature proton exchange membrane fuel cells (HT-PEMFC) has been summarized. The paper focuses on phosphoric acid-doped polybenzimidazole (PBI)-based HT-PEMFCs and an overview of the common practices...

Glial Cells: The Other Cells of the Nervous System

Indian Academy of Sciences (India)

nervous system. The present .... In the vertebrate nervous system, special types of cells called radial glia .... As men- tioned earlier, astrocytes extend a 'foot process' (Figure 3) that ... capillaries that for a long time it was thought that these cells.

Hydrogen Research for Spaceport and Space-Based Applications: Fuel Cell Projects

Science.gov (United States)

Anderson, Tim; Balaban, Canan

2008-01-01

The activities presented are a broad based approach to advancing key hydrogen related technologies in areas such as fuel cells, hydrogen production, and distributed sensors for hydrogen-leak detection, laser instrumentation for hydrogen-leak detection, and cryogenic transport and storage. Presented are the results from research projects, education and outreach activities, system and trade studies. The work will aid in advancing the state-of-the-art for several critical technologies related to the implementation of a hydrogen infrastructure. Activities conducted are relevant to a number of propulsion and power systems for terrestrial, aeronautics and aerospace applications. Fuel cell research focused on proton exchange membranes (PEM), solid oxide fuel cells (SOFC). Specific technologies included aircraft fuel cell reformers, new and improved electrodes, electrolytes, interconnect, and seals, modeling of fuel cells including CFD coupled with impedance spectroscopy. Research was conducted on new materials and designs for fuel cells, along with using embedded sensors with power management electronics to improve the power density delivered by fuel cells. Fuel cell applications considered were in-space operations, aviation, and ground-based fuel cells such as; powering auxiliary power units (APUs) in aircraft; high power density, long duration power supplies for interplanetary missions (space science probes and planetary rovers); regenerative capabilities for high altitude aircraft; and power supplies for reusable launch vehicles.

Biomek Cell Workstation: A Variable System for Automated Cell Cultivation.

Science.gov (United States)

Lehmann, R; Severitt, J C; Roddelkopf, T; Junginger, S; Thurow, K

2016-06-01

Automated cell cultivation is an important tool for simplifying routine laboratory work. Automated methods are independent of skill levels and daily constitution of laboratory staff in combination with a constant quality and performance of the methods. The Biomek Cell Workstation was configured as a flexible and compatible system. The modified Biomek Cell Workstation enables the cultivation of adherent and suspension cells. Until now, no commercially available systems enabled the automated handling of both types of cells in one system. In particular, the automated cultivation of suspension cells in this form has not been published. The cell counts and viabilities were nonsignificantly decreased for cells cultivated in AutoFlasks in automated handling. The proliferation of manual and automated bioscreening by the WST-1 assay showed a nonsignificant lower proliferation of automatically disseminated cells associated with a mostly lower standard error. The disseminated suspension cell lines showed different pronounced proliferations in descending order, starting with Jurkat cells followed by SEM, Molt4, and RS4 cells having the lowest proliferation. In this respect, we successfully disseminated and screened suspension cells in an automated way. The automated cultivation and dissemination of a variety of suspension cells can replace the manual method. © 2015 Society for Laboratory Automation and Screening.

Ion, X-ray, UV and Neutron Microbeam Systems for Cell Irradiation.

Science.gov (United States)

Bigelow, A W; Randers-Pehrson, G; Garty, G; Geard, C R; Xu, Y; Harken, A D; Johnson, G W; Brenner, D J

2010-08-08

The array of microbeam cell-irradiation systems, available to users at the Radiological Research Accelerator Facility (RARAF), Center for Radiological Research, Columbia University, is expanding. The HVE 5MV Singletron particle accelerator at the facility provides particles to two focused ion microbeam lines: the sub-micron microbeam II and the permanent magnetic microbeam (PMM). Both the electrostatic quadrupole lenses on the microbeam II system and the magnetic quadrupole lenses on the PMM system are arranged as compound lenses consisting of two quadrupole triplets with "Russian" symmetry. Also, the RARAF accelerator is a source for a proton-induced x-ray microbeam (undergoing testing) and is projected to supply protons to a neutron microbeam based on the (7)Li(p, n)(7)Be nuclear reaction (under development). Leveraging from the multiphoton microscope technology integrated within the microbeam II endstation, a UV microspot irradiator - based on multiphoton excitation - is available for facility users. Highlights from radiation-biology demonstrations on single living mammalian cells are included in this review of microbeam systems for cell irradiation at RARAF.

Hybrid energy fuel cell based system for household applications in a Mediterranean climate

International Nuclear Information System (INIS)

Nižetić, S.; Tolj, I.; Papadopoulos, A.M.

2015-01-01

Highlights: • A hybrid energy system was proposed, combining a HT-PEM fuel cell system and a standard split heat pump system with heat recovery for household applications. • The hybrid energy system is able to produce both high and low temperature heat, electricity and cooling capacity. • The system showed high overall energy efficiency and a favorable environmental aspect. • The calculated cost of overall produced energy proved to be competitive in comparison with the average cost of electricity for households. - Abstract: In this paper, a specific hybrid energy system was proposed for household applications. The hybrid energy system was assembled from a HT-PEM fuel cell stack supplied by hydrogen via a steam reformer, where finally the majority of produced electricity is used to drive a modified split heat pump system with heat recovery (that is enabled via standard modified accumulation boilers). The system is able to produce both high and low temperature heat output (in the form of hot water), cooling thermal output and electricity. Performance analysis was conducted and the specific hybrid energy system showed high value for overall energy efficiency, for the specific case examined it reached 250%. Levelized Cost of Energy (LCOE) analysis was also carried out and the proposed hybrid energy system’s cost is expected to be between 0.09 €/kW h and 0.16 €/kW h, which is certainly competitive with the current retail electricity price for households on the EU market. Additionally, the system also has environmental benefits in relation to reduced CO 2 emissions, as estimated CO 2 emissions from the proposed hybrid energy system are expected to be at around 9.0 gCO 2 /kW h or 2.6 times less than the emissions released from the utilization of grid electricity.

Elementary kinetic modelling applied to solid oxide fuel cell pattern anodes and a direct flame fuel cell system

Energy Technology Data Exchange (ETDEWEB)

Vogler, Marcel

2009-05-27

In the course of this thesis a model for the prediction of polarisation characteristics of solid oxide fuel cells (SOFC) was developed. The model is based on an elementary kinetic description of electrochemical reactions and the fundamental conservation principles of mass and energy. The model allows to predict the current-voltage relation of an SOFC and offers ideal possibilities for model validation. The aim of this thesis is the identification of rate-limiting processes and the determination of the elementary pathway during charge transfer. The numerical simulation of experiments with model anodes allowed to identify a hydrogen transfer to be the most probable charge-transfer reaction and revealed the influence of diffusive transport. Applying the hydrogen oxidation kinetics to the direct flame fuel cell system (DFFC) showed that electrochemical oxidation of CO is possible based on the same mechanism. Based on the quantification of loss processes in the DFFC system, improvements on cell design, predicting 80% increase of efficiency, were proposed. (orig.)

A solid oxide fuel cell system for buildings

International Nuclear Information System (INIS)

Zink, Florian; Lu, Yixin; Schaefer, Laura

2007-01-01

This paper examines an integrated solid oxide fuel cell (SOFC) absorption heating and cooling system used for buildings. The integrated system can provide heating/cooling and/or hot water for buildings while consuming natural gas. The aim of this study is to give an overall description of the system. The possibility of such an integrated system is discussed and the configuration of the system is described. A system model is presented, and a specific case study of the system, which consists of a pre-commercial SOFC system and a commercial LiBr absorption system, is performed. In the case study, the detailed configuration of an integrated system is given, and the heat and mass balance and system performance are obtained through numerical calculation. Based on the case study, some considerations with respect to system component selection, system configuration and design are discussed. Additionally, the economic and environmental issues of this specific system are evaluated briefly. The results show that the combined system demonstrates great advantages in both technical and environmental aspects. With the present development trends in solid oxide fuel cells and the commercial status of absorption heating and cooling systems, it is very likely that such a combined system will become increasingly feasible within the following decade

Reduced cells based on extremal principles

International Nuclear Information System (INIS)

Gruber, B.

1989-01-01

It is known that the Buerger cell, a+b+c=abs min, is ambiguous. Uniqueness is usually achieved by an additional system of inequalities which leads to the generally accepted Niggli cell. However, this system is rather unusual and does not suggest any geometrical meaning for the Niggli cell. In this paper four types of unique cells originating from the Buerger cell are introduced by means of simple conditions which have an extremal character. Any of these cells may stand for a reduced cell and has an express geometrical property. One of the four types coincides with the Niggli cell, which is thus given a geometrical interpretation. Systems of inequalities are shown that allow recognition of the cell of any type and algorithms are presented for achieving it. An algorithm for obtaining all Buerger cells of a lattice is included. The use of the reciprocal lattice enables the definition of four further unique cells which, however, need not be Buerger cells and are not discussed in detail. The mathematics must deal with a number of inequalities which often contain square roots, and sometimes rather intricate technical tricks are required. (orig.)

Cell phone based balance trainer

Directory of Open Access Journals (Sweden)

Lee Beom-Chan

2012-02-01

Full Text Available Abstract Background In their current laboratory-based form, existing vibrotactile sensory augmentation technologies that provide cues of body motion are impractical for home-based rehabilitation use due to their size, weight, complexity, calibration procedures, cost, and fragility. Methods We have designed and developed a cell phone based vibrotactile feedback system for potential use in balance rehabilitation training in clinical and home environments. It comprises an iPhone with an embedded tri-axial linear accelerometer, custom software to estimate body tilt, a "tactor bud" accessory that plugs into the headphone jack to provide vibrotactile cues of body tilt, and a battery. Five young healthy subjects (24 ± 2.8 yrs, 3 females and 2 males and four subjects with vestibular deficits (42.25 ± 13.5 yrs, 2 females and 2 males participated in a proof-of-concept study to evaluate the effectiveness of the system. Healthy subjects used the system with eyes closed during Romberg, semi-tandem Romberg, and tandem Romberg stances. Subjects with vestibular deficits used the system with both eyes-open and eyes-closed conditions during semi-tandem Romberg stance. Vibrotactile feedback was provided when the subject exceeded either an anterior-posterior (A/P or a medial-lateral (M/L body tilt threshold. Subjects were instructed to move away from the vibration. Results The system was capable of providing real-time vibrotactile cues that informed corrective postural responses. When feedback was available, both healthy subjects and those with vestibular deficits significantly reduced their A/P or M/L RMS sway (depending on the direction of feedback, had significantly smaller elliptical area fits to their sway trajectory, spent a significantly greater mean percentage time within the no feedback zone, and showed a significantly greater A/P or M/L mean power frequency. Conclusion The results suggest that the real-time feedback provided by this system can be used

Cell phone based balance trainer

Science.gov (United States)

2012-01-01

Background In their current laboratory-based form, existing vibrotactile sensory augmentation technologies that provide cues of body motion are impractical for home-based rehabilitation use due to their size, weight, complexity, calibration procedures, cost, and fragility. Methods We have designed and developed a cell phone based vibrotactile feedback system for potential use in balance rehabilitation training in clinical and home environments. It comprises an iPhone with an embedded tri-axial linear accelerometer, custom software to estimate body tilt, a "tactor bud" accessory that plugs into the headphone jack to provide vibrotactile cues of body tilt, and a battery. Five young healthy subjects (24 ± 2.8 yrs, 3 females and 2 males) and four subjects with vestibular deficits (42.25 ± 13.5 yrs, 2 females and 2 males) participated in a proof-of-concept study to evaluate the effectiveness of the system. Healthy subjects used the system with eyes closed during Romberg, semi-tandem Romberg, and tandem Romberg stances. Subjects with vestibular deficits used the system with both eyes-open and eyes-closed conditions during semi-tandem Romberg stance. Vibrotactile feedback was provided when the subject exceeded either an anterior-posterior (A/P) or a medial-lateral (M/L) body tilt threshold. Subjects were instructed to move away from the vibration. Results The system was capable of providing real-time vibrotactile cues that informed corrective postural responses. When feedback was available, both healthy subjects and those with vestibular deficits significantly reduced their A/P or M/L RMS sway (depending on the direction of feedback), had significantly smaller elliptical area fits to their sway trajectory, spent a significantly greater mean percentage time within the no feedback zone, and showed a significantly greater A/P or M/L mean power frequency. Conclusion The results suggest that the real-time feedback provided by this system can be used to reduce body sway. Its

A portable cell-based impedance sensor for toxicity testing of drinking water.

Science.gov (United States)

Curtis, Theresa M; Widder, Mark W; Brennan, Linda M; Schwager, Steven J; van der Schalie, William H; Fey, Julien; Salazar, Noe

2009-08-07

A major limitation to using mammalian cell-based biosensors for field testing of drinking water samples is the difficulty of maintaining cell viability and sterility without an on-site cell culture facility. This paper describes a portable automated bench-top mammalian cell-based toxicity sensor that incorporates enclosed fluidic biochips containing endothelial cells monitored by Electric Cell-substrate Impedance Sensing (ECIS) technology. Long-term maintenance of cells on the biochips is made possible by using a compact, self-contained disposable media delivery system. The toxicity sensor monitors changes in impedance of cell monolayers on the biochips after the introduction of water samples. The fluidic biochip includes an ECIS electronic layer and a polycarbonate channel layer, which together reduce initial impedance disturbances seen in commercially available open well ECIS chips caused by the mechanics of pipetting while maintaining the ability of the cells to respond to toxicants. A curve discrimination program was developed that compares impedance values over time between the control and treatment channels on the fluidic biochip and determines if they are significantly different. Toxicant responses of bovine pulmonary artery endothelial cells grown on fluidic biochips are similar to cells on commercially-available open well chips, and these cells can be maintained in the toxicity sensor device for at least nine days using an automated media delivery system. Longer-term cell storage is possible; bovine lung microvessel endothelial cells survive for up to four months on the fluidic biochips and remain responsive to a model toxicant. This is the first demonstration of a portable bench top system capable of both supporting cell health over extended periods of time and obtaining impedance measurements from endothelial cell monolayers after toxicant exposure.

Bioreactors to influence stem cell fate: augmentation of mesenchymal stem cell signaling pathways via dynamic culture systems.

Science.gov (United States)

Yeatts, Andrew B; Choquette, Daniel T; Fisher, John P

2013-02-01

Mesenchymal stem cells (MSCs) are a promising cell source for bone and cartilage tissue engineering as they can be easily isolated from the body and differentiated into osteoblasts and chondrocytes. A cell based tissue engineering strategy using MSCs often involves the culture of these cells on three-dimensional scaffolds; however the size of these scaffolds and the cell population they can support can be restricted in traditional static culture. Thus dynamic culture in bioreactor systems provides a promising means to culture and differentiate MSCs in vitro. This review seeks to characterize key MSC differentiation signaling pathways and provides evidence as to how dynamic culture is augmenting these pathways. Following an overview of dynamic culture systems, discussion will be provided on how these systems can effectively modify and maintain important culture parameters including oxygen content and shear stress. Literature is reviewed for both a highlight of key signaling pathways and evidence for regulation of these signaling pathways via dynamic culture systems. The ability to understand how these culture systems are affecting MSC signaling pathways could lead to a shear or oxygen regime to direct stem cell differentiation. In this way the efficacy of in vitro culture and differentiation of MSCs on three-dimensional scaffolds could be greatly increased. Bioreactor systems have the ability to control many key differentiation stimuli including mechanical stress and oxygen content. The further integration of cell signaling investigations within dynamic culture systems will lead to a quicker realization of the promise of tissue engineering and regenerative medicine. This article is part of a Special Issue entitled Biochemistry of Stem Cells. Copyright © 2012 Elsevier B.V. All rights reserved.

The Celution® System: Automated Processing of Adipose-Derived Regenerative Cells in a Functionally Closed System.

Science.gov (United States)

Fraser, John K; Hicok, Kevin C; Shanahan, Rob; Zhu, Min; Miller, Scott; Arm, Douglas M

2014-01-01

Objective: To develop a closed, automated system that standardizes the processing of human adipose tissue to obtain and concentrate regenerative cells suitable for clinical treatment of thermal and radioactive burn wounds. Approach: A medical device was designed to automate processing of adipose tissue to obtain a clinical-grade cell output of stromal vascular cells that may be used immediately as a therapy for a number of conditions, including nonhealing wounds resulting from radiation damage. Results: The Celution ® System reliably and reproducibly generated adipose-derived regenerative cells (ADRCs) from tissue collected manually and from three commercial power-assisted liposuction devices. The entire process of introducing tissue into the system, tissue washing and proteolytic digestion, isolation and concentration of the nonadipocyte nucleated cell fraction, and return to the patient as a wound therapeutic, can be achieved in approximately 1.5 h. An alternative approach that applies ultrasound energy in place of enzymatic digestion demonstrates extremely poor efficiency cell extraction. Innovation: The Celution System is the first medical device validated and approved by multiple international regulatory authorities to generate autologous stromal vascular cells from adipose tissue that can be used in a real-time bedside manner. Conclusion: Initial preclinical and clinical studies using ADRCs obtained using the automated tissue processing Celution device described herein validate a safe and effective manner to obtain a promising novel cell-based treatment for wound healing.

An estimation of the water balance in a reformer/fuel-cells system

Energy Technology Data Exchange (ETDEWEB)

Jovan, Vladimir [Jo-ef Stefan Institute and Centre of Excellence Low-Carbon Technologies (Slovenia); Cufar, Alja [University of Ljubljana, Faculty of Mathematics and Physics (Slovenia)], e-mail: vladimir.jovan@ijs.si

2011-07-01

PEM fuel cells use hydrogen as fuel. Since it is a very light element, its energy density is small despite its high caloric value. Thus hydrogen storage requires a lot of space. One possible solution is simultaneous production of hydrogen from higher-density materials, such as methanol. The object of this paper is to determine what is the total water balance in a system consisting of a methanol reformer and a fuel-cells-based generator set, and to determine if water should be supplied to, or removed from, the system. Based on relatively little information obtained from technical sources and on some simple assumptions, this paper presents a model which helps to determine the actual water balance in the system. In conclusion, commercially available fuel-cell systems with realistic water production can be used for fuel reforming purposes in the methanol reformer. It is also shown that under normal operating conditions, and using commercially available devices, there is always an excess of water produced.

Perfusion based cell culture chips

DEFF Research Database (Denmark)

Heiskanen, Arto; Emnéus, Jenny; Dufva, Martin

2010-01-01

Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures...... and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers....

A quantitative system for discriminating induced pluripotent stem cells, embryonic stem cells and somatic cells.

Directory of Open Access Journals (Sweden)

Anyou Wang

Full Text Available Induced pluripotent stem cells (iPSCs derived from somatic cells (SCs and embryonic stem cells (ESCs provide promising resources for regenerative medicine and medical research, leading to a daily identification of new cell lines. However, an efficient system to discriminate the different types of cell lines is lacking. Here, we develop a quantitative system to discriminate the three cell types, iPSCs, ESCs, and SCs. The system consists of DNA-methylation biomarkers and mathematical models, including an artificial neural network and support vector machines. All biomarkers were unbiasedly selected by calculating an eigengene score derived from analysis of genome-wide DNA methylations. With 30 biomarkers, or even with as few as 3 top biomarkers, this system can discriminate SCs from pluripotent cells (PCs, including ESCs and iPSCs with almost 100% accuracy. With approximately 100 biomarkers, the system can distinguish ESCs from iPSCs with an accuracy of 95%. This robust system performs precisely with raw data without normalization as well as with converted data in which the continuous methylation levels are accounted. Strikingly, this system can even accurately predict new samples generated from different microarray platforms and the next-generation sequencing. The subtypes of cells, such as female and male iPSCs and fetal and adult SCs, can also be discriminated with this method. Thus, this novel quantitative system works as an accurate framework for discriminating the three cell types, iPSCs, ESCs, and SCs. This strategy also supports the notion that DNA-methylation generally varies among the three cell types.

The Characterisation of a PEM Fuel-Cell System with a Focus on UAS Applications

Science.gov (United States)

2014-01-01

low specific power (W/kg) [3-6]. This has stimulated the development of hybrid systems that utilise a combination of battery and fuel - cell ...battery-powered systems (i.e., electric motors and batteries). However, the great advantage of fuel - cell -based powerplants is their specific energy...alkaline-electrolyte, direct- methanol , and sulphur-oxide fuel cells ) are also required so that a broad assessment of fuel - cell types and their likely

Automated Cell Enrichment of Cytomegalovirus-specific T cells for Clinical Applications using the Cytokine-capture System.

Science.gov (United States)

Kumaresan, Pappanaicken; Figliola, Mathew; Moyes, Judy S; Huls, M Helen; Tewari, Priti; Shpall, Elizabeth J; Champlin, Richard; Cooper, Laurence J N

2015-10-05

The adoptive transfer of pathogen-specific T cells can be used to prevent and treat opportunistic infections such as cytomegalovirus (CMV) infection occurring after allogeneic hematopoietic stem-cell transplantation. Viral-specific T cells from allogeneic donors, including third party donors, can be propagated ex vivo in compliance with current good manufacturing practice (cGMP), employing repeated rounds of antigen-driven stimulation to selectively propagate desired T cells. The identification and isolation of antigen-specific T cells can also be undertaken based upon the cytokine capture system of T cells that have been activated to secrete gamma-interferon (IFN-γ). However, widespread human application of the cytokine capture system (CCS) to help restore immunity has been limited as the production process is time-consuming and requires a skilled operator. The development of a second-generation cell enrichment device such as CliniMACS Prodigy now enables investigators to generate viral-specific T cells using an automated, less labor-intensive system. This device separates magnetically labeled cells from unlabeled cells using magnetic activated cell sorting technology to generate clinical-grade products, is engineered as a closed system and can be accessed and operated on the benchtop. We demonstrate the operation of this new automated cell enrichment device to manufacture CMV pp65-specific T cells obtained from a steady-state apheresis product obtained from a CMV seropositive donor. These isolated T cells can then be directly infused into a patient under institutional and federal regulatory supervision. All the bio-processing steps including removal of red blood cells, stimulation of T cells, separation of antigen-specific T cells, purification, and washing are fully automated. Devices such as this raise the possibility that T cells for human application can be manufactured outside of dedicated good manufacturing practice (GMP) facilities and instead be produced

Improvement of Bioactive Compound Classification through Integration of Orthogonal Cell-Based Biosensing Methods

Directory of Open Access Journals (Sweden)

Goran N. Jovanovic

2007-01-01

Full Text Available Lack of specificity for different classes of chemical and biological agents, and false positives and negatives, can limit the range of applications for cell-based biosensors. This study suggests that the integration of results from algal cells (Mesotaenium caldariorum and fish chromatophores (Betta splendens improves classification efficiency and detection reliability. Cells were challenged with paraquat, mercuric chloride, sodium arsenite and clonidine. The two detection systems were independently investigated for classification of the toxin set by performing discriminant analysis. The algal system correctly classified 72% of the bioactive compounds, whereas the fish chromatophore system correctly classified 68%. The combined classification efficiency was 95%. The algal sensor readout is based on fluorescence measurements of changes in the energy producing pathways of photosynthetic cells, whereas the response from fish chromatophores was quantified using optical density. Change in optical density reflects interference with the functioning of cellular signal transduction networks. Thus, algal cells and fish chromatophores respond to the challenge agents through sufficiently different mechanisms of action to be considered orthogonal.

Optimization of mass of plastic scintillator film for flow-cell based tritium monitoring: a Monte Carlo study

International Nuclear Information System (INIS)

Roy, Arup Singha; Palani Selvam, T.; Raman, Anand; Raja, V.; Chaudhury, Probal

2014-01-01

Over the years, various types of tritium-in-air monitors have been designed and developed based on different principles. Ionization chamber, proportional counter and scintillation detector systems are few among them. A plastic scintillator based, flow-cell type online tritium-in-air monitoring system was developed for online monitoring of tritium in air. The value of the scintillator mass inside the cell-volume, which maximizes the response of the detector system, should be obtained to get maximum efficiency. The present study is aimed to optimize the amount of mass of the plastic scintillator film for the flow-cell based tritium monitoring instrument so that maximum efficiency is achieved. The Monte Carlo based EGSnrc code system has been used for this purpose

Possible configurations for an air independent propulsion (AIP) system for submarines based on fuel cells

International Nuclear Information System (INIS)

Bordallo, C.R.; Moreno, E.; Brey, J.J.; Garcia, C.; Sarmiento, B.; Castro, A.

2004-01-01

'Full text:' Conventional submarines employ an electric propulsion system, based on energy storage in batteries which are recharged using diesel motors connected to generator alternators. This limits their autonomy underwater given that it will be depend on the amount of energy that can be stored in the batteries; currently, a normal value is to have energy to navigate for three days at low speed. As of from the WWII, several shipyards began to carry out research on propulsion systems for submarines that would be capable of operating under anaerobic conditions, independent of the air (AIP Systems). Since then, several proposals have been considered, but there is one option that several navies are currently putting their trust in: fuel cells. The objective of this Project is to stress the different configurations that can be considered to this end, as regards the transportation of hydrogen and oxygen. From the hydrogen point of view, the possibilities of transporting it in metal hydrides or its on-board production through the reforming of different fuels (gas-oil, ethanol, methanol), are analyzed. This study also compares auxiliary systems (including CO2 removers), and proposes solutions, some of which are under development, indicating which are currently being considered to a greater extent. (author)

Possible configurations for an air independent propulsion (AIP) system for submarines based on fuel cells

Energy Technology Data Exchange (ETDEWEB)

Bordallo, C.R.; Moreno, E.; Brey, J.J.; Garcia, C.; Sarmiento, B.; Castro, A. [Hynergreen Technologies, S.A., Seville (Spain)

2004-07-01

'Full text:' Conventional submarines employ an electric propulsion system, based on energy storage in batteries which are recharged using diesel motors connected to generator alternators. This limits their autonomy underwater given that it will be depend on the amount of energy that can be stored in the batteries; currently, a normal value is to have energy to navigate for three days at low speed. As of from the WWII, several shipyards began to carry out research on propulsion systems for submarines that would be capable of operating under anaerobic conditions, independent of the air (AIP Systems). Since then, several proposals have been considered, but there is one option that several navies are currently putting their trust in: fuel cells. The objective of this Project is to stress the different configurations that can be considered to this end, as regards the transportation of hydrogen and oxygen. From the hydrogen point of view, the possibilities of transporting it in metal hydrides or its on-board production through the reforming of different fuels (gas-oil, ethanol, methanol), are analyzed. This study also compares auxiliary systems (including CO2 removers), and proposes solutions, some of which are under development, indicating which are currently being considered to a greater extent. (author)

An assessment of the energetic flows in a commercial PEM fuel-cell system

International Nuclear Information System (INIS)

Jovan, Vladimir; Perne, Matija; Petrovcic, Janko

2010-01-01

Some primary issues have not yet been fully investigated on the way towards the commercialization of fuel-cell-based systems (FCS), e.g., their actual efficiency, reliability, safety, degradation, maintainability, etc. This article deals with an estimation of the real energetic flows and the corresponding electrical efficiency of a commercial proton-exchange-membrane fuel-cell hydrogen-fed generator set (PEMFCS). The fuel-cell power system considered here is planned to be the source of both electrical and thermal energy in a mobile dwelling container unit with in-built fuel-cell-based cogeneration system, and for the design of a cogeneration unit the actual amount of disposable energy from the PEMFC unit should be estimated. The assessment of the actual energetic flows, the disposable energy and the consequent electrical efficiency of the case-study PEMFCS is carried out using commercial technical data for the PEMFCS.

Hybrid systems with lead-acid battery and proton-exchange membrane fuel cell

Science.gov (United States)

Jossen, Andreas; Garche, Juergen; Doering, Harry; Goetz, Markus; Knaupp, Werner; Joerissen, Ludwig

Hybrid systems, based on a lead-acid battery and a proton-exchange membrane fuel cell (PEMFC) give the possibility to combine the advantages of both technologies. The benefits for different applications are discussed and the practical realisation of such systems is shown. Furthermore a numerical model for such a hybrid system is described and results are shown and discussed. The results show that the combination of lead-acid batteries and PEMFC shows advantages in case of applications with high peak power requirements (i.e. electric scooter) and applications where the fuel cell is used as auxiliary power supply to recharge the battery. The high efficiency of fuel cells at partial load operation results in a good fuel economy for recharging of lead-acid batteries with a fuel cell system.

Graphene-Based Systems for Energy Storage

Science.gov (United States)

Calle, Carlos I.; Mackey, Paul J.; Johansen, Michael R.; Phillips, James, III; Hogue, Michael; Kaner, Richard B.; El-Kady, Maher

2016-01-01

Development of graphene-based energy storage devices based on the Laser Scribe system developed by the University of California Los Angeles. These devices These graphene-based devices store charge on graphene sheets and take advantage of the large accessible surface area of graphene (2,600 m2g) to increase the electrical energy that can be stored. The proposed devices should have the electrical storage capacity of thin-film-ion batteries but with much shorter charge discharge cycle times as well as longer lives The proposed devices will be carbon-based and so will not have the same issues with flammability or toxicity as the standard lithium-based storage cells.

A Web-Based Integration Procedure for the Development of Reconfigurable Robotic Work-Cells

Directory of Open Access Journals (Sweden)

Paulo Ferreira

2013-07-01

Full Text Available Concepts related to the development of reconfigurable manufacturing systems (RMS and methodologies to provide the best practices in the processing industry and factory automation, such as system integration and web-based technology, are major issues in designing next-generation manufacturing systems (NGMS. Adaptable and integrable devices are crucial for the success of NGMS. In robotic cells the integration of manufacturing components is essential to accelerate system adaptability. Sensors, control architectures and communication technologies have contributed to achieving further agility in reconfigurable factories. In this work a web-based robotic cell integration procedure is proposed to aid the identification of reconfigurable issues and requirements. This methodology is applied to an industrial robot manipulator to enhance system flexibility towards the development of a reconfigurable robotic platform.

Fuel cell systems

International Nuclear Information System (INIS)

Kotevski, Darko

2003-01-01

Fuel cell systems are an entirely different approach to the production of electricity than traditional technologies. They are similar to the batteries in that both produce direct current through electrochemical process. There are six types of fuel cells each with a different type of electrolyte, but they all share certain important characteristics: high electrical efficiency, low environmental impact and fuel flexibility. Fuel cells serve a variety of applications: stationary power plants, transport vehicles and portable power. That is why world wide efforts are addressed to improvement of this technology. (Original)

Passive hybridization of a photovoltaic module with lithium-ion battery cells: A model-based analysis

Science.gov (United States)

Joos, Stella; Weißhar, Björn; Bessler, Wolfgang G.

2017-04-01

Standard photovoltaic battery systems based on AC or DC architectures require power electronics and controllers, including inverters, MPP tracker, and battery charger. Here we investigate an alternative system design based on the parallel connection of a photovoltaic module with battery cells without any intermediate voltage conversion. This approach, for which we use the term passive hybridization, is based on matching the solar cell's and battery cell's respective current/voltage behavior. A battery with flat discharge characteristics can allow to pin the solar cell to its maximum power point (MPP) independently of the external power consumption. At the same time, upon battery full charge, voltage increase will drive the solar cell towards zero current and therefore self-prevent battery overcharge. We present a modeling and simulation analysis of passively hybridizing a 5 kWp PV system with a 5 kWh LFP/graphite lithium-ion battery. Dynamic simulations with 1-min time resolution are carried out for three exemplary summer and winter days using historic weather data and a synthetic single-family household consumer profile. The results demonstrate the feasibility of the system. The passive hybrid allows for high self-sufficiencies of 84.6% in summer and 25.3% in winter, which are only slightly lower than those of a standard system.

Detection of pollutants in aquatic media using a cell-based sensor

OpenAIRE

Guijarro Řezníček, Christian

2016-01-01

Water is a precious good which in good quality we need essentially to survive. In this work a novel method for the detection of bioactive pollutants in aqueous media will be presented. It is based on a sensor system, which uses mammalian cells, RLC-18 (rat liver cells) or MCF-7 (breast cancer cell line) as the detection layer for harmful substances. With these mammalian cells as the sensing layer a metabolically active sensor interface will become available reflecting the physiology of living...

Electrokinetic gated injection-based microfluidic system for quantitative analysis of hydrogen peroxide in individual HepG2 cells.

Science.gov (United States)

Zhang, Xinyuan; Li, Qingling; Chen, Zhenzhen; Li, Hongmin; Xu, Kehua; Zhang, Lisheng; Tang, Bo

2011-03-21

A microfluidic system to determine hydrogen peroxide (H(2)O(2)) in individual HepG2 cells based on the electrokinetic gated injection was developed for the first time. A home-synthesized fluorescent probe, bis(p-methylbenzenesulfonate)dichlorofluorescein (FS), was employed to label intracellular H(2)O(2) in the intact cells. On a simple cross microchip, multiple single-cell operations, including single cell injection, cytolysis, electrophoresis separation and detection of H(2)O(2), were automatically carried out within 60 s using the electrokinetic gated injection and laser-induced fluorescence detection (LIFD). The performance of the method was evaluated under the optimal conditions. The linear calibration curve was over a range of 4.39-610 amol (R(2)=0.9994). The detection limit was 0.55 amol or 9.0×10(-10) M (S/N=3). The relative standard deviations (RSDs, n=6) of migration time and peak area were 1.4% and 4.8%, respectively. With the use of this method, the average content of H(2)O(2) in single HepG2 cells was found to be 16.09±9.84 amol (n=15). Separation efficiencies in excess of 17,000 theoretical plates for the cells were achieved. These results demonstrated that the efficient integration and automation of these single-cell operations enabled the sensitive, reproducible, and quantitative examination of intracellular H(2)O(2) at single-cell level. Owing to the advantages of simple microchip structure, controllable single-cell manipulation and ease in building, this platform provides a universal way to automatically determine other intracellular constituents within single cells. This journal is © The Royal Society of Chemistry 2011

Expression of variable viruses as herpes simplex glycoprotein D and varicella zoster gE glycoprotein using a novel plasmid based expression system in insect cell

Directory of Open Access Journals (Sweden)

A.M. Al-Sulaiman

2017-11-01

Full Text Available Several prokaryotic and eukaryotic expression systems have been used for in vitro production of viruses’ proteins. However eukaryotic expression system was always the first choice for production of proteins that undergo post-translational modification such as glycosylation. Recombinant baculoviruses have been widely used as safe vectors to express heterologous genes in the culture of insect cells, but the manipulation involved in creating, titrating, and amplifying viral stocks make it time consuming and laborious. Therefore, to facilitate rapid expression in insect cell, a plasmid based expression system was used to express herpes simplex type 1 glycoprotein D (HSV-1 gD and varicella zoster glycoprotein E (VZV gE. Recombinant plasmids were generated, transfected into insect cells (SF9, and both glycoproteins were expressed 48 h post-infection. A protein with approximately molecular weight of 64-kDa and 98-kDa for HSV-1 gD and VZV gE respectively was expressed and confirmed by SDS. Proteins were detected in insect cells cytoplasm and outer membrane by immunofluorescence. The antigenicity and immunoreactivity of each protein were confirmed by immunoblot and ELISA. Results suggest that this system can be an alternative to the traditional baculovirus expression for small scale expression system in insect cells.

Radiobiology of Cell Renewal Systems

Energy Technology Data Exchange (ETDEWEB)

Patt, H. M. [Laboratory of Radiobiology, University of California Medical Center, San Francisco, CA (United States)

1968-08-15

In recent years, considerable attention has been given to quantitative aspects of radiation effects on cell renewal systems. The behaviour of stem-type cells has been a focal point of interest, and it has been assumed by many that the fraction of surviving stem cells is the principal determinant of the probability of survival of the irradiated system or organism. The apparent close similarity in dose requirements for impairment of reproductive capacity, and the similarity in early repair and in stage sensitivity in vitro and in vivo.clearly indicate that purely cellular phenomena are reflected in the organized population. It does not necessarily follow, however, that there is a straightforward relationship between radiation effects on stem cells and the response of systems or organisms. Indeed, this is not so. It is abundantly clear that differential radiosensitivity is anchored in a number of variables that are associated with the organizational framework of the system and its environment. Many, but not all, effects can be understood in terms of the normal kinetics of the developmental pathway. Yet, deviations from normal kinetics that are minor in the steady state can have profound significance in the perturbed state. To understand the radiobiology of cell renewal systems and to place the many possible variables in reasonable perspective, we need to know a good deal more about the interplay of the component parts than we do at present. When we view the totality of an organized cell population, it seems necessary to postulate mechanisms external to any given cell in the regulation of the balanced sequence of proliferation and differentiation. At present, we have only a vague idea about this. Most attention has been directed to the proliferative process and it is encouraging to note the growing interest in the more developmental facets of cell renewal. (author)

Development of droplets‐based microfluidic systems for single­‐cell high‐throughput screening

DEFF Research Database (Denmark)

Chen, Jun; Jensen, Thomas Glasdam; Godina, Alexei

2014-01-01

High-throughput screening (HTS) plays an important role in the development of microbial cell factories. One of the most popular approaches is to use microplates combined with the application of robotics, liquid handling and sophisticated detection methods. However, these workstations require large...... investment, and a logarithmic increase to screen large combinatorial libraries over the decades also makes it gradually out of depth. Here, we are trying to develop a feasible high‐throughput system that uses microfluidics to compartmentalize a single cell for propagation and analysis in monodisperse...... picoliter aqueous droplets surround by an immiscible fluorinated oil phase. Our aim is to use this system to facilitate the screening process for both the biotechnology and food industry....

Fuel cells, batteries and super-capacitors stand-alone power systems management using optimal/flatness based-control

Energy Technology Data Exchange (ETDEWEB)

Benaouadj, M.; Aboubou, A.; Bahri, M.; Boucetta, A. [MSE Laboratory, Mohamed khiderBiskra University (Algeria); Ayad, M. Y., E-mail: ayadmy@gmail.com [R& D, Industrial Hybrid Vehicle Applications (France)

2016-07-25

In this work, an optimal control (under constraints) based on the Pontryagin’s maximum principle is used to optimally manage energy flows in a basic PEM (Proton Exchange Membrane) fuel cells system associated to lithium-ion batteries and supercapacitors through a common DC bus having a voltage to stabilize using the differential flatness approach. The adaptation of voltage levels between different sources and load is ensured by use of three DC-DC converters, one boost connected to the PEM fuel cells, while the two others are buck/boost and connected to the lithiumion batteries and supercapacitors. The aim of this paper is to develop an energy management strategy that is able to satisfy the following objectives: Impose the power requested by a habitat (representing the load) according to a proposed daily consumption profile, Keep fuel cells working at optimal power delivery conditions, Maintain constant voltage across the common DC bus, Stabilize the batteries voltage and stored quantity of charge at desired values given by the optimal control. Results obtained under MATLAB/Simulink environment prove that the cited objectives are satisfied, validating then, effectiveness and complementarity between the optimal and flatness concepts proposed for energy management. Note that this study is currently in experimentally validation within MSE Laboratory.

A new MATLAB/Simulink model of triple-junction solar cell and MPPT based on artificial neural networks for photovoltaic energy systems

Directory of Open Access Journals (Sweden)

Hegazy Rezk

2015-09-01

Full Text Available This paper presents a new Matlab/Simulink model of a PV module and a maximum power point tracking (MPPT system for high efficiency InGaP/InGaAs/Ge triple-junction solar cell. The proposed technique is based on Artificial Neural Network. The equivalent circuit model of the triple-junction solar cell includes the parameters of each sub-cell. It is also include the effect of the temperature variations on the energy gap of each sub-cell as well as the diode reverse saturation currents. The implementation of a PV model is based on the triple-junction solar cell in the form of masked block in Matlab/Simulink software package that has a user-friendly icon and dialog. It is fast and accurate technique to follow the maximum power point. The simulation results of the proposed MPPT technique are compared with Perturb and Observe MPPT technique. The output power and energy of the proposed technique are higher than that of the Perturb and Observe MPPT technique. The proposed technique increases the output energy per day for a one PV module from 3.37 kW h to 3.75 kW h, i.e. a percentage of 11.28%.

Proton exchange membrane fuel cell systems engineering at Vickers Shipbuilding and Engineering Limited (VSEL)

Science.gov (United States)

Seymour, C. M.

1992-01-01

A project, jointly funded by VSEL and CJB Developments Limited, is aimed at the development of complete power generation systems based on PEM fuel cell technology. Potential markets for such systems are seen as being very broadly based, ranging from military land and marine systems through to commercial on-site power generation and transport. From the outset the project was applications driven, the intent being to identify market requirements, in terms of system specifications and to use these to produce development targets. The two companies have based their work on the Ballard PEM stack and have focused their efforts on the development of supporting systems. This benefits all three companies as it allows Ballard to obtain applications information on which to base future research and VSEL/CJBD are able to capitalise on the advanced development of the Ballard stack. Current work is focused on the production of a 20 kW, methanol fuelled, power generation system demonstrator, although work is also in hand to address a wider range of fuels including natural gas. The demonstrator, when complete, will be used to indicate the potential benefits of such systems and to act as a design aid for the applications phase of the project. Preliminary work on this next phase is already in hand, with studies to assess both systems and fuel cell stack design requirements for specific applications and to generate concept designs. Work to date has concentrated on the development of a methanol reformer, suitable for integration into a fuel cell system and on extensive testing and evaluation of the Ballard fuel cell stacks. This testing has covered a wide range of operating parameters, including different fuel and oxidant combinations. The effect of contaminants on the performance and life of the fuel cells is also under evaluation. PEM fuel cells still require a great deal of further development if they are to gain widespread commercial acceptance. A recent study conducted by VSEL in

Design considerations for a 10-KW integrated hydrogen-oxygen regenerative fuel cell system

International Nuclear Information System (INIS)

Hoberecht, M.A.; Gonzalez-Sanabria, O.D.; Miller, T.B.; Rieker, L.L.

1984-01-01

Integration of an alkaline fuel cell subsystem with an alkaline electrolysis subsystem to form a regenerative fuel cell (RFC) system for low-earth-orbit (LEO) applications characterized by relatively high overall round-trip electrical efficiency, long life, and high reliability is possible with present state-of-the-art technology. A hypothetical 10-kW system is being computer modeled and studied based on data from ongoing contractual efforts in both the alkaline fuel cell and alkaline water electrolysis areas. The alkaline fuel cell technology is being developed under an NASA-LeRC program with United Technologies Corporation (UTC), utilizing advanced cell components and standard Shuttle-Orbiter system hardware. The alkaline electrolysis technology is that of Life Systems, Inc. (LSI), which uses a static water vapor feed technique and scaled-up cell hardware being developed under an NASA-LeRC program. This paper addresses the computeraided study of the performance, operating, and design parameters of the hypothetical system

Dynamic cultivation of human mesenchymal stem cells in a rotating bed bioreactor system based on the Z RP platform.

Science.gov (United States)

Diederichs, Solvig; Röker, Stefanie; Marten, Dana; Peterbauer, Anja; Scheper, Thomas; van Griensven, Martijn; Kasper, Cornelia

2009-01-01

Because the regeneration of large bone defects is limited by quantitative restrictions and risks of infections, the development of bioartificial bone substitutes is of great importance. To obtain a three-dimensional functional tissue-like graft, static cultivation is inexpedient due to limitations in cell density, nutrition and oxygen support. Dynamic cultivation in a bioreactor system can overcome these restrictions and furthermore provide the possibility to control the environment with regard to pH, oxygen content, and temperature. In this study, a three-dimensional bone construct was engineered by the use of dynamic bioreactor technology. Human adipose tissue derived mesenchymal stem cells were cultivated on a macroporous zirconium dioxide based ceramic disc called Sponceram. Furthermore, hydroxyapatite coated Sponceram was used. The cells were cultivated under dynamic conditions and compared with statically cultivated cells. The differentiation into osteoblasts was initiated by osteogenic supplements. Cellular proliferation during static and dynamic cultivation was compared measuring glucose and lactate concentration. The differentiation process was analysed determining AP-expression and using different specific staining methods. Our results demonstrate much higher proliferation rates during dynamic conditions in the bioreactor system compared to static cultivation measured by glucose consumption and lactate production. Cell densities on the scaffolds indicated higher proliferation on native Sponceram compared to hydroxyapatite coated Sponceram. With this study, we present an excellent method to enhance cellular proliferation and bone lineage specific growth of tissue like structures comprising fibrous (collagen) and globular (mineral) extracellular components. (c) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009.

Bioreactor process monitoring using an automated microfluidic platform for cell-based assays

DEFF Research Database (Denmark)

Rodrigues de Sousa Nunes, Pedro André; Kjaerulff, S.; Dufva, Martin

2015-01-01

We report on a novel microfluidic system designed to monitor in real-time the concentration of live and dead cells in industrial cell production. Custom-made stepper motor actuated peristaltic pumps and valves, fluidic interconnections, sample-to-waste liquid management and image cytometry-based ...

Paper-based membraneless hydrogen peroxide fuel cell prepared by micro-fabrication

Science.gov (United States)

Mousavi Ehteshami, Seyyed Mohsen; Asadnia, Mohsen; Tan, Swee Ngin; Chan, Siew Hwa

2016-01-01

A paper-based membraneless single-compartment hydrogen peroxide power source prepared by micro-electromechanical systems (MEMS) technology is reported. The cell utilizes hydrogen peroxide as both fuel and oxidant in a low volume cell fabricated on paper. The fabrication method used is a simple method where precise, small-sized patterns are produced which include the hydrophilic paper bounded by hydrophobic resin. Open circuit potentials of 0.61 V and 0.32 V are achieved for the cells fabricated with Prussian Blue as the cathode and aluminium/nickel as the anode materials, respectively. The power produced by the cells is 0.81 mW cm-2 at 0.26 V and 0.38 mW cm-2 at 0.14 V, respectively, even after the cell is bent or distorted. Such a fuel cell provides an easily fabricated, environmentally friendly, flexible and cost saving power source. The cell may be integrated within a self-sustained diagnostic system to provide the on-demand power for future bio-sensing applications.

A Novel Cell-Based Hybrid Acoustic Wave Biosensor with Impedimetric Sensing Capabilities

Science.gov (United States)

Liu, Fei; Li, Fang; Nordin, Anis Nurashikin; Voiculescu, Ioana

2013-01-01

A novel multiparametric biosensor system based on living cells will be presented. The biosensor system includes two biosensing techniques on a single device: resonant frequency measurements and electric cell-substrate impedance sensing (ECIS). The multiparametric sensor system is based on the innovative use of the upper electrode of a quartz crystal microbalance (QCM) resonator as working electrode for the ECIS technique. The QCM acoustic wave sensor consists of a thin AT-cut quartz substrate with two gold electrodes on opposite sides. For integration of the QCM with the ECIS technique a semicircular counter electrode was fabricated near the upper electrode on the same side of the quartz crystal. Bovine aortic endothelial live cells (BAECs) were successfully cultured on this hybrid biosensor. Finite element modeling of the bulk acoustic wave resonator using COMSOL simulations was performed. Simultaneous gravimetric and impedimetric measurements performed over a period of time on the same cell culture were conducted to validate the device's sensitivity. The time necessary for the BAEC cells to attach and form a compact monolayer on the biosensor was 35∼45 minutes for 1.5 × 104 cells/cm2 BAECs; 60 minutes for 2.0 × 104 cells/cm2 BAECs; 70 minutes for 3.0 × 104 cells/cm2 BAECs; and 100 minutes for 5.0 × 104 cells/cm2 BAECs. It was demonstrated that this time is the same for both gravimetric and impedimetric measurements. This hybrid biosensor will be employed in the future for water toxicity detection. PMID:23459387

A Novel Cell-Based Hybrid Acoustic Wave Biosensor with Impedimetric Sensing Capabilities

Directory of Open Access Journals (Sweden)

Ioana Voiculescu

2013-03-01

Full Text Available A novel multiparametric biosensor system based on living cells will be presented. The biosensor system includes two biosensing techniques on a single device: resonant frequency measurements and electric cell-substrate impedance sensing (ECIS. The multiparametric sensor system is based on the innovative use of the upper electrode of a quartz crystal microbalance (QCM resonator as working electrode for the ECIS technique. The QCM acoustic wave sensor consists of a thin AT-cut quartz substrate with two gold electrodes on opposite sides. For integration of the QCM with the ECIS technique a semicircular counter electrode was fabricated near the upper electrode on the same side of the quartz crystal. Bovine aortic endothelial live cells (BAECs were successfully cultured on this hybrid biosensor. Finite element modeling of the bulk acoustic wave resonator using COMSOL simulations was performed. Simultaneous gravimetric and impedimetric measurements performed over a period of time on the same cell culture were conducted to validate the device’s sensitivity. The time necessary for the BAEC cells to attach and form a compact monolayer on the biosensor was 35~45 minutes for 1.5 × 104 cells/cm2 BAECs; 60 minutes for 2.0 × 104 cells/cm2 BAECs; 70 minutes for 3.0 × 104 cells/cm2 BAECs; and 100 minutes for 5.0 × 104 cells/cm2 BAECs. It was demonstrated that this time is the same for both gravimetric and impedimetric measurements. This hybrid biosensor will be employed in the future for water toxicity detection.

Cellular bases of radiation-induced residual insufficiency in the haematopoietic system

International Nuclear Information System (INIS)

Wangenheim, K.H. v.; Peterson, H.P.; Feinendegen, L.E.

1984-01-01

Following radiation exposure, man's survival and further well-being largely depends on the degree of damage to his heamatopietic system. Stem cells are particualarly sensitive to radiation. Over and beyond acute radiation damge, residual radiation damage is of significance since it reduces the performance of the haematopietic system and enhances the risk of leukaemia. Knowledge concerning cellular bases may be important for preventive and therapeutic measures. The measurement method presented is based on the fact that stem cells from transfused bone marrow will settle in the spleen of highly irradiated mice and be able to reconstruct the haematopietic system. Initally individual colonies can be observed which originate from a single stem cell and the proliferation of its descendants. Counting these colonies will give the number of stem cells. The reduction of the proliferation factor measured in the stem-cell quality test apparently is not due to a shift in the age structure of the stem cell compartment but to a damage which is located within a more or less substantial proportion of the stem cells themselves. This damage is the cause of stem cell descendant growth retarded on an average. It is probable that recovery observed after irradiation is brought about by less-damaged or undamaged stem cells replacing damaged ones. Initial results point to the fact that this replacement can be influenced by treatment after irradiation. (orig./MG) [de

Bacterial spread from cell to cell: beyond actin-based motility.

Science.gov (United States)

Kuehl, Carole J; Dragoi, Ana-Maria; Talman, Arthur; Agaisse, Hervé

2015-09-01

Several intracellular pathogens display the ability to propagate within host tissues by displaying actin-based motility in the cytosol of infected cells. As motile bacteria reach cell-cell contacts they form plasma membrane protrusions that project into adjacent cells and resolve into vacuoles from which the pathogen escapes, thereby achieving spread from cell to cell. Seminal studies have defined the bacterial and cellular factors that support actin-based motility. By contrast, the mechanisms supporting the formation of protrusions and their resolution into vacuoles have remained elusive. Here, we review recent advances in the field showing that Listeria monocytogenes and Shigella flexneri have evolved pathogen-specific mechanisms of bacterial spread from cell to cell. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nonlinear observer designs for fuel cell power systems

Science.gov (United States)

Gorgun, Haluk

A fuel cell is an electrochemical device that combines hydrogen and oxygen, with the aid of electro-catalysts, to produce electricity. A fuel cell consists of a negatively charged anode, a positively charged cathode and an electrolyte, which transports protons or ions. A low temperature fuel cell has an electrical potential of about 0.7 Volt when generating a current density of 300--500 mA/cm2. Practical fuel cell power systems will require a combination of several cells in series (a stack) to satisfy the voltage requirements of specific applications. Fuel cells are suitable for a potentially wide variety of applications, from stationary power generation in the range of hundreds of megawatts to portable electronics in the range of a couple of watts. Efficient operation of a fuel cell system requires advanced feedback control designs. Reliable measurements from the system are necessary to implement such designs. However, most of the commercially available sensors do not operate properly in the reformate and humidified gas streams in fuel cell systems. Sensors working varying degrees of success are too big and costly, and sensors that are potentially low cost are not reliable or do not have the required life time [28]. Observer designs would eliminate sensor needs for measurements, and make feedback control implementable. Since the fuel cell system dynamics are highly nonlinear, observer design is not an easy task. In this study we aim to develop nonlinear observer design methods applicable to fuel cell systems. In part I of the thesis we design an observer to estimate the hydrogen partial pressure in the anode channel. We treat inlet partial pressure as an unknown slowly varying parameter and develop an adaptive observer that employs a nonlinear voltage injection term. However in this design Fuel Processing System (FPS) dynamics are not modelled, and their effect on the anode dynamics are treated as plant uncertainty. In part II of the thesis we study the FPS

Lipid-Based Nanovectors for Targeting of CD44-Overexpressing Tumor Cells

Directory of Open Access Journals (Sweden)

Silvia Arpicco

2013-01-01

Full Text Available Hyaluronic acid (HA is a naturally occurring glycosaminoglycan that exists in living systems, and it is a major component of the extracellular matrix. The hyaluronic acid receptor CD44 is found at low levels on the surface of epithelial, haematopoietic, and neuronal cells and is overexpressed in many cancer cells particularly in tumour initiating cells. HA has been therefore used as ligand attached to HA-lipid-based nanovectors for the active targeting of small or large active molecules for the treatment of cancer. This paper describes the different approaches employed for the preparation, characterization, and evaluation of these potent delivery systems.

Artificial neural network-aided image analysis system for cell counting.

Science.gov (United States)

Sjöström, P J; Frydel, B R; Wahlberg, L U

1999-05-01

In histological preparations containing debris and synthetic materials, it is difficult to automate cell counting using standard image analysis tools, i.e., systems that rely on boundary contours, histogram thresholding, etc. In an attempt to mimic manual cell recognition, an automated cell counter was constructed using a combination of artificial intelligence and standard image analysis methods. Artificial neural network (ANN) methods were applied on digitized microscopy fields without pre-ANN feature extraction. A three-layer feed-forward network with extensive weight sharing in the first hidden layer was employed and trained on 1,830 examples using the error back-propagation algorithm on a Power Macintosh 7300/180 desktop computer. The optimal number of hidden neurons was determined and the trained system was validated by comparison with blinded human counts. System performance at 50x and lO0x magnification was evaluated. The correlation index at 100x magnification neared person-to-person variability, while 50x magnification was not useful. The system was approximately six times faster than an experienced human. ANN-based automated cell counting in noisy histological preparations is feasible. Consistent histology and computer power are crucial for system performance. The system provides several benefits, such as speed of analysis and consistency, and frees up personnel for other tasks.

Embedded system based on PWM control of hydrogen generator with SEPIC converter

Science.gov (United States)

Fall, Cheikh; Setiawan, Eko; Habibi, Muhammad Afnan; Hodaka, Ichijo

2017-09-01

The objective of this paper is to design and to produce a micro electrical plant system based on fuel cell for teaching material-embedded systems in technical vocational training center. Based on this, the student can experience generating hydrogen by fuel cells, controlling the rate of hydrogen generation by the duty ration of single-ended primary-inductor converter(SEPIC), drawing the curve rate of hydrogen to duty ratio, generating electrical power by using hydrogen, and calculating the fuel cell efficiency when it is used as electrical energy generator. This project is of great importance insofar as students will need to acquire several skills to be able to realize it such as continuous DC DC conversion and the scientific concept behind the converter, the regulation of systems with integral proportional controllers, the installation of photovoltaic cells, the use of high-tech sensors, microcontroller programming, object-oriented programming, mastery of the fuel cell syste

Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads.

Science.gov (United States)

Wang, Lin; Acosta, Miguel A; Leach, Jennie B; Carrier, Rebecca L

2013-04-21

Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems.

Acid base activity of live bacteria: Implications for quantifying cell wall charge

Science.gov (United States)

Claessens, Jacqueline; van Lith, Yvonne; Laverman, Anniet M.; Van Cappellen, Philippe

2006-01-01

To distinguish the buffering capacity associated with functional groups in the cell wall from that resulting from metabolic processes, base or acid consumption by live and dead cells of the Gram-negative bacterium Shewanella putrefaciens was measured in a pH stat system. Live cells exhibited fast consumption of acid (pH 4) or base (pH 7, 8, 9, and 10) during the first few minutes of the experiments. At pH 5.5, no acid or base was required to maintain the initial pH constant. The initial amounts of acid or base consumed by the live cells at pH 4, 8, and 10 were of comparable magnitudes as those neutralized at the same pHs by intact cells killed by exposure to gamma radiation or ethanol. Cells disrupted in a French press required higher amounts of acid or base, due to additional buffering by intracellular constituents. At pH 4, acid neutralization by suspensions of live cells stopped after 50 min, because of loss of viability. In contrast, under neutral and alkaline conditions, base consumption continued for the entire duration of the experiments (5 h). This long-term base neutralization was, at least partly, due to active respiration by the cells, as indicated by the build-up of succinate in solution. Qualitatively, the acid-base activity of live cells of the Gram-positive bacterium Bacillus subtilis resembled that of S. putrefaciens. The pH-dependent charging of ionizable functional groups in the cell walls of the live bacteria was estimated from the initial amounts of acid or base consumed in the pH stat experiments. From pH 4 to 10, the cell wall charge increased from near-zero values to about -4 × 10 -16 mol cell -1 and -6.5 × 10 -16 mol cell -1 for S. putrefaciens and B. subtilis, respectively. The similar cell wall charging of the two bacterial strains is consistent with the inferred low contribution of lipopolysaccharides to the buffering capacity of the Gram-negative cell wall (of the order of 10%).

Stem Cell-Based Neuroprotective and Neurorestorative Strategies

Directory of Open Access Journals (Sweden)

Chia-Wei Hung

2010-05-01

Full Text Available Stem cells, a special subset of cells derived from embryo or adult tissues, are known to present the characteristics of self-renewal, multiple lineages of differentiation, high plastic capability, and long-term maintenance. Recent reports have further suggested that neural stem cells (NSCs derived from the adult hippocampal and subventricular regions possess the utilizing potential to develop the transplantation strategies and to screen the candidate agents for neurogenesis, neuroprotection, and neuroplasticity in neurodegenerative diseases. In this article, we review the roles of NSCs and other stem cells in neuroprotective and neurorestorative therapies for neurological and psychiatric diseases. We show the evidences that NSCs play the key roles involved in the pathogenesis of several neurodegenerative disorders, including depression, stroke and Parkinson’s disease. Moreover, the potential and possible utilities of induced pluripotent stem cells (iPS, reprogramming from adult fibroblasts with ectopic expression of four embryonic genes, are also reviewed and further discussed. An understanding of the biophysiology of stem cells could help us elucidate the pathogenicity and develop new treatments for neurodegenerative disorders. In contrast to cell transplantation therapies, the application of stem cells can further provide a platform for drug discovery and small molecular testing, including Chinese herbal medicines. In addition, the high-throughput stem cell-based systems can be used to elucidate the mechanisms of neuroprotective candidates in translation medical research for neurodegenerative diseases.

Development, analysis and assessment of a fuel cell and solar photovoltaic system powered vehicle

International Nuclear Information System (INIS)

Ezzat, M.F.; Dincer, I.

2016-01-01

Highlights: • A new integrated fuel cell-photovoltaic system for vehicle application is proposed. • Comprehensive energy and exergy analyses are conducted. • Detailed parametric study is performed. • Overall energy and exergy efficiencies are determined. • Photovoltaic utilization can save 561 g of hydrogen during 3 h drive. - Abstract: This paper deals with a new hybridly powered photovoltaic-fuel cell - Li-ion battery integrated system and is compared to a base system, consisting of PEM fuel cell and Li-ion battery. It investigates the effects of adding photovoltaic arrays to the base system and further effects on the overall energy and exergy efficiencies and hence hydrogen consumption. These two systems are analyzed and assessed both energetically and exergetically. The study results show that the overall energy and exergy efficiencies become 39.46% and 56.3%, respectively at a current density of 1150 mA/cm"2 for system 1 (fuel cell-battery). Moreover, energy and exergy efficiencies are found to be 39.86% and 56.63% at current density of 1150 mA/cm"2 for system 2 (fuel cell-battery-photovoltaics). Utilizing photovoltaic arrays in system 2 would recover 561 g of hydrogen through 3 h of continuous driving at max power of 98.32 kW, which is approximately 11.2% of the hydrogen storage tank used in the proposed systems. The effects of changing various system parameters on energy and exergy efficiencies of the overall system are also examined.

The design of in-cell crane handling systems for nuclear plants

International Nuclear Information System (INIS)

Hansford, S.M.; Scott, R.

1992-01-01

The reprocessing and waste management facilities at (BNFL's) British Nuclear Fuels Limited's Sellafield site make extensive use of crane handling systems. These range from conventional mechanical handling operations as used generally in industry to high integrity applications through to remote robotic handling operations in radiation environments. This paper describes the design methodologies developed for the design of crane systems for remote handling operations - in-cell crane systems. In most applications the in-cell crane systems are an integral part of the plant process equipment and reliable and safe operations are a key design parameter. Outlined are the techniques developed to achieve high levels of crane system availability for operations in hazardous radiation environments. These techniques are now well established and proven through many years of successful plant operation. A recent application of in-cell crane handling systems design for process duty application is described. The benefits of a systematic design approach and a functionally-based engineering organization are also highlighted. (author)

Design considerations for a 10-kW integrated hydrogen-oxygen regenerative fuel cell system

Science.gov (United States)

Hoberecht, M. A.; Miller, T. B.; Rieker, L. L.; Gonzalez-Sanabria, O. D.

1984-01-01

Integration of an alkaline fuel cell subsystem with an alkaline electrolysis subsystem to form a regenerative fuel cell (RFC) system for low earth orbit (LEO) applications characterized by relatively high overall round trip electrical efficiency, long life, and high reliability is possible with present state of the art technology. A hypothetical 10 kW system computer modeled and studied based on data from ongoing contractual efforts in both the alkaline fuel cell and alkaline water electrolysis areas. The alkaline fuel cell technology is under development utilizing advanced cell components and standard Shuttle Orbiter system hardware. The alkaline electrolysis technology uses a static water vapor feed technique and scaled up cell hardware is developed. The computer aided study of the performance, operating, and design parameters of the hypothetical system is addressed.

Real cell overlay measurement through design based metrology

Science.gov (United States)

Yoo, Gyun; Kim, Jungchan; Park, Chanha; Lee, Taehyeong; Ji, Sunkeun; Jo, Gyoyeon; Yang, Hyunjo; Yim, Donggyu; Yamamoto, Masahiro; Maruyama, Kotaro; Park, Byungjun

2014-04-01

Until recent device nodes, lithography has been struggling to improve its resolution limit. Even though next generation lithography technology is now facing various difficulties, several innovative resolution enhancement technologies, based on 193nm wavelength, were introduced and implemented to keep the trend of device scaling. Scanner makers keep developing state-of-the-art exposure system which guarantees higher productivity and meets a more aggressive overlay specification. "The scaling reduction of the overlay error has been a simple matter of the capability of exposure tools. However, it is clear that the scanner contributions may no longer be the majority component in total overlay performance. The ability to control correctable overlay components is paramount to achieve the desired performance.(2)" In a manufacturing fab, the overlay error, determined by a conventional overlay measurement: by using an overlay mark based on IBO and DBO, often does not represent the physical placement error in the cell area of a memory device. The mismatch may arise from the size or pitch difference between the overlay mark and the cell pattern. Pattern distortion, caused by etching or CMP, also can be a source of the mismatch. Therefore, the requirement of a direct overlay measurement in the cell pattern gradually increases in the manufacturing field, and also in the development level. In order to overcome the mismatch between conventional overlay measurement and the real placement error of layer to layer in the cell area of a memory device, we suggest an alternative overlay measurement method utilizing by design, based metrology tool. A basic concept of this method is shown in figure1. A CD-SEM measurement of the overlay error between layer 1 and 2 could be the ideal method but it takes too long time to extract a lot of data from wafer level. An E-beam based DBM tool provides high speed to cover the whole wafer with high repeatability. It is enabled by using the design as a

Quantifying the mechanical micro-environment during three-dimensional cell expansion on microbeads by means of individual cell-based modelling.

Science.gov (United States)

Smeets, Bart; Odenthal, Tim; Tijskens, Engelbert; Ramon, Herman; Van Oosterwyck, Hans

2013-10-01

Controlled in vitro three-dimensional cell expansion requires culture conditions that optimise the biophysical micro-environment of the cells during proliferation. In this study, we propose an individual cell-based modelling platform for simulating the mechanics of cell expansion on microcarriers. The lattice-free, particle-based method considers cells as individual interacting particles that deform and move over time. The model quantifies how the mechanical micro-environment of individual cells changes during the time of confluency. A sensitivity analysis is performed, which shows that changes in the cell-specific properties of cell-cell adhesion and cell stiffness cause the strongest change in the mechanical micro-environment of the cells. Furthermore, the influence of the mechanical properties of cells and microbead is characterised. The mechanical micro-environment is strongly influenced by the adhesive properties and the size of the microbead. Simulations show that even in the absence of strong biological heterogeneity, a large heterogeneity in mechanical stresses can be expected purely due to geometric properties of the culture system.

Glial Cells: The Other Cells of the Nervous System

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 1. Glial Cells: The Other Cells of the Nervous System - An Introduction to Glial Cells. Medha S Rajadhyaksha Yasmin Khan. Series Article Volume 7 Issue 1 January 2002 pp 4-10 ...

Economic competitiveness of fuel cell onsite integrated energy systems

Science.gov (United States)

Bollenbacher, G.

1983-01-01

The economic competitiveness of fuel cell onsite integrated energy systems (OS/IES) in residential and commercial buildings is examined. The analysis is carried out for three different buildings with each building assumed to be at three geographic locations spanning a range of climatic conditions. Numerous design options and operating strategies are evaluated and two economic criteria are used to measure economic performance. In general the results show that fuel cell OS/IES's are competitive in most regions of the country if the OS/IES is properly designed. The preferred design is grid connected, makes effective use of the fuel cell's thermal output, and has a fuel cell powerplant sized for the building's base electrical load.

Bioreactors for high cell density and continuous multi-stage cultivations: options for process intensification in cell culture-based viral vaccine production.

Science.gov (United States)

Tapia, Felipe; Vázquez-Ramírez, Daniel; Genzel, Yvonne; Reichl, Udo

2016-03-01

With an increasing demand for efficacious, safe, and affordable vaccines for human and animal use, process intensification in cell culture-based viral vaccine production demands advanced process strategies to overcome the limitations of conventional batch cultivations. However, the use of fed-batch, perfusion, or continuous modes to drive processes at high cell density (HCD) and overextended operating times has so far been little explored in large-scale viral vaccine manufacturing. Also, possible reductions in cell-specific virus yields for HCD cultivations have been reported frequently. Taking into account that vaccine production is one of the most heavily regulated industries in the pharmaceutical sector with tough margins to meet, it is understandable that process intensification is being considered by both academia and industry as a next step toward more efficient viral vaccine production processes only recently. Compared to conventional batch processes, fed-batch and perfusion strategies could result in ten to a hundred times higher product yields. Both cultivation strategies can be implemented to achieve cell concentrations exceeding 10(7) cells/mL or even 10(8) cells/mL, while keeping low levels of metabolites that potentially inhibit cell growth and virus replication. The trend towards HCD processes is supported by development of GMP-compliant cultivation platforms, i.e., acoustic settlers, hollow fiber bioreactors, and hollow fiber-based perfusion systems including tangential flow filtration (TFF) or alternating tangential flow (ATF) technologies. In this review, these process modes are discussed in detail and compared with conventional batch processes based on productivity indicators such as space-time yield, cell concentration, and product titers. In addition, options for the production of viral vaccines in continuous multi-stage bioreactors such as two- and three-stage systems are addressed. While such systems have shown similar virus titers compared to

MR-based imaging of neural stem cells

Energy Technology Data Exchange (ETDEWEB)

Politi, Letterio S. [San Raffaele Scientific Institute, Neuroradiology Department, Milano (Italy)

2007-06-15

The efficacy of therapies based on neural stem cells (NSC) has been demonstrated in preclinical models of several central nervous system (CNS) diseases. Before any potential human application of such promising therapies can be envisaged, there are some important issues that need to be solved. The most relevant one is the requirement for a noninvasive technique capable of monitoring NSC delivery, homing to target sites and trafficking. Knowledge of the location and temporospatial migration of either transplanted or genetically modified NSC is of the utmost importance in analyzing mechanisms of correction and cell distribution. Further, such a technique may represent a crucial step toward clinical application of NSC-based approaches in humans, for both designing successful protocols and monitoring their outcome. Among the diverse imaging approaches available for noninvasive cell tracking, such as nuclear medicine techniques, fluorescence and bioluminescence, magnetic resonance imaging (MRI) has unique advantages. Its high temporospatial resolution, high sensitivity and specificity render MRI one of the most promising imaging modalities available, since it allows dynamic visualization of migration of transplanted cells in animal models and patients during clinically useful time periods. Different cellular and molecular labeling approaches for MRI depiction of NSC are described and discussed in this review, as well as the most relevant issues to be considered in optimizing molecular imaging techniques for clinical application. (orig.)

MR-based imaging of neural stem cells

International Nuclear Information System (INIS)

Politi, Letterio S.

2007-01-01

The efficacy of therapies based on neural stem cells (NSC) has been demonstrated in preclinical models of several central nervous system (CNS) diseases. Before any potential human application of such promising therapies can be envisaged, there are some important issues that need to be solved. The most relevant one is the requirement for a noninvasive technique capable of monitoring NSC delivery, homing to target sites and trafficking. Knowledge of the location and temporospatial migration of either transplanted or genetically modified NSC is of the utmost importance in analyzing mechanisms of correction and cell distribution. Further, such a technique may represent a crucial step toward clinical application of NSC-based approaches in humans, for both designing successful protocols and monitoring their outcome. Among the diverse imaging approaches available for noninvasive cell tracking, such as nuclear medicine techniques, fluorescence and bioluminescence, magnetic resonance imaging (MRI) has unique advantages. Its high temporospatial resolution, high sensitivity and specificity render MRI one of the most promising imaging modalities available, since it allows dynamic visualization of migration of transplanted cells in animal models and patients during clinically useful time periods. Different cellular and molecular labeling approaches for MRI depiction of NSC are described and discussed in this review, as well as the most relevant issues to be considered in optimizing molecular imaging techniques for clinical application. (orig.)

GEM System: automatic prototyping of cell-wide metabolic pathway models from genomes

Directory of Open Access Journals (Sweden)

Nakayama Yoichi

2006-03-01

Full Text Available Abstract Background Successful realization of a "systems biology" approach to analyzing cells is a grand challenge for our understanding of life. However, current modeling approaches to cell simulation are labor-intensive, manual affairs, and therefore constitute a major bottleneck in the evolution of computational cell biology. Results We developed the Genome-based Modeling (GEM System for the purpose of automatically prototyping simulation models of cell-wide metabolic pathways from genome sequences and other public biological information. Models generated by the GEM System include an entire Escherichia coli metabolism model comprising 968 reactions of 1195 metabolites, achieving 100% coverage when compared with the KEGG database, 92.38% with the EcoCyc database, and 95.06% with iJR904 genome-scale model. Conclusion The GEM System prototypes qualitative models to reduce the labor-intensive tasks required for systems biology research. Models of over 90 bacterial genomes are available at our web site.

Numerical investigation of heat pipe-based photovoltaic–thermoelectric generator (HP-PV/TEG) hybrid system

International Nuclear Information System (INIS)

Makki, Adham; Omer, Siddig; Su, Yuehong; Sabir, Hisham

2016-01-01

Highlights: • Integration of TE generators with a heat pipe-based PV module as a hybrid system is proposed. • Numerical transient modeling based on the energy balance equations of the system was performed. • Integration of TE generators with PV module aid operating the solar cells at a steady level in harsh conditions. - Abstract: Photovoltaic (PV) cells are able to absorb about 80% of the solar spectral irradiance, however, certain percentage accounts for electricity conversion depending on the cell technology employed. The remainder energy however, can elevate the silicon junction temperature in the PV encapsulation perilously, resulting in deteriorated performance. Temperature rise at the PV cell level is addressed as one of the most critical issues that can seriously degrade and shortens the life-time of the PV cells, hence thermal management of the PV module during operation is considered essential. Hybrid PV designs which are able to simultaneously generate electrical energy and utilize the waste heat have been proven to be the most promising solution. In this study, theoretical investigation of a hybrid system comprising of thermoelectric generator integration with a heat pipe-based Photovoltaic/Thermal (PV/T) absorber is proposed and evaluated. The system presented incorporates a PV panel for direct electricity generation, a heat pipe for excessive heat absorption from the PV cells and a thermoelectric generator (TEG) performing direct heat-to-electricity conversion. A mathematical model based on the energy balance within the system is developed to evaluate the performance of the hybrid integration and the improvements associated with the thermal management of PV cells. Results are presented in terms of the overall system efficiency compared to a conventional PV panel under identical operating conditions. The integration of TEG modules with PV cells in such way aid improving the performance of the PV cells in addition to utilizing the waste

A novel poly(propylene-co-imidazole) based biofuel cell: System optimization and operation for energy generation

Energy Technology Data Exchange (ETDEWEB)

Kilic, Muhammet Samet [Department of Chemistry, Bulent Ecevit University, 67100 Zonguldak (Turkey); Korkut, Seyda, E-mail: s.korkut@beun.edu.tr [Department of Environmental Engineering, Bulent Ecevit University, 67100 Zonguldak (Turkey); Hazer, Baki [Department of Chemistry, Bulent Ecevit University, 67100 Zonguldak (Turkey)

2015-02-01

This study describes the construction of an enzymatic fuel cell comprised of novel gold nanoparticles embedded poly(propylene-co-imidazole) coated anode and cathode. Working electrode fabrication steps and operational conditions for the fuel cell have been optimized to get enhanced power output. Electrical generation capacity of the optimized cell was tested by using the municipal wastewater sample. The enzymatic fuel cell system reached to maximum power density with 1 μg and 8 μg of polymer quantity and bilirubin oxidase on electrode surface, respectively. The maximum power output was calculated to be 5 μW cm{sup −2} at + 0.56 V (vs. Ag/AgCl) in phosphate buffer (pH 7.4, 100 mM, 20 °C) by the addition of 15 mM of glucose as a fuel source. The optimized enzymatic fuel cell generated a power density of 0.46 μW cm{sup −2} for the municipal wastewater sample. Poly(propylene-co-imidazole) was easily used for a fuel cell system owing to its metallic nanoparticle content. The developed fuel cell will play a significant role for energy conversion by using glucose readily found in wastewater and in vivo mediums. - Highlights: • Gold nanoparticles provided faster electron transfer in the circuit. • The maximum power density of 5 μW cm{sup −2} was generated at + 0.56 V cell potential. • The cell can be easily operated for in vivo mediums.

A methodology for thermo-economic modeling and optimization of solid oxide fuel cell systems

International Nuclear Information System (INIS)

Palazzi, Francesca; Autissier, Nordahl; Marechal, Francois M.A.; Favrat, Daniel

2007-01-01

In the context of stationary power generation, fuel cell-based systems are being foreseen as a valuable alternative to thermodynamic cycle-based power plants, especially in small scale applications. As the technology is not yet established, many aspects of fuel cell development are currently investigated worldwide. Part of the research focuses on integrating the fuel cell in a system that is both efficient and economically attractive. To address this problem, we present in this paper a thermo-economic optimization method that systematically generates the most attractive configurations of an integrated system. In the developed methodology, the energy flows are computed using conventional process simulation software. The system is integrated using the pinch based methods that rely on optimization techniques. This defines the minimum of energy required and sets the basis to design the ideal heat exchanger network. A thermo-economic method is then used to compute the integrated system performances, sizes and costs. This allows performing the optimization of the system with regard to two objectives: minimize the specific cost and maximize the efficiency. A solid oxide fuel cell (SOFC) system of 50 kW integrating a planar SOFC is modeled and optimized leading to designs with efficiencies ranging from 34% to 44%. The multi-objective optimization strategy identifies interesting system configurations and their performance for the developed SOFC system model. The methods proves to be an attractive tool to be used both as an advanced analysis tool and as support to decision makers when designing new systems