Systematic design of broadband path-coiling acoustic metamaterials

NASA Astrophysics Data System (ADS)

Jia, Zhetao; Li, Junfei; Shen, Chen; Xie, Yangbo; Cummer, Steven A.

2018-01-01

A design approach for acoustic metamaterial unit cells based on a coiled path with impedance matching layers (IMLs) is proposed in this paper. A theoretical approach is developed to calculate the transmission of the labyrinthine unit cells with different effective refractive indices. The IML is introduced to broaden the transmission bandwidth and produce a lower envelope boundary of transmission for unit cells of different effective refractive indices. According to the theory, cells of all effective refractive indices can be built to achieve unitary transmission at center working frequencies. The working frequency can be tuned by adjusting the length of the IML. Numerical simulations based on finite element analysis are used to validate the theoretical predictions. The high transmission and low dispersive index nature of our designs are further verified by experiments within a broad frequency band of over 1.4 kHz centered at 2.86 kHz. Our design approach can be useful in various wavefront engineering applications.

Silicon Nanowire/Polymer Hybrid Solar Cell-Supercapacitor: A Self-Charging Power Unit with a Total Efficiency of 10.5.

PubMed

Liu, Ruiyuan; Wang, Jie; Sun, Teng; Wang, Mingjun; Wu, Changsheng; Zou, Haiyang; Song, Tao; Zhang, Xiaohong; Lee, Shuit-Tong; Wang, Zhong Lin; Sun, Baoquan

2017-07-12

An integrated self-charging power unit, combining a hybrid silicon nanowire/polymer heterojunction solar cell with a polypyrrole-based supercapacitor, has been demonstrated to simultaneously harvest solar energy and store it. By efficiency enhancement of the hybrid nanowire solar cells and a dual-functional titanium film serving as conjunct electrode of the solar cell and supercapacitor, the integrated system is able to yield a total photoelectric conversion to storage efficiency of 10.5%, which is the record value in all the integrated solar energy conversion and storage system. This system may not only serve as a buffer that diminishes the solar power fluctuations from light intensity, but also pave its way toward cost-effective high efficiency self-charging power unit. Finally, an integrated device based on ultrathin Si substrate is demonstrated to expand its feasibility and potential application in flexible energy conversion and storage devices.

Realisation of all 16 Boolean logic functions in a single magnetoresistance memory cell

NASA Astrophysics Data System (ADS)

Gao, Shuang; Yang, Guang; Cui, Bin; Wang, Shouguo; Zeng, Fei; Song, Cheng; Pan, Feng

2016-06-01

Stateful logic circuits based on next-generation nonvolatile memories, such as magnetoresistance random access memory (MRAM), promise to break the long-standing von Neumann bottleneck in state-of-the-art data processing devices. For the successful commercialisation of stateful logic circuits, a critical step is realizing the best use of a single memory cell to perform logic functions. In this work, we propose a method for implementing all 16 Boolean logic functions in a single MRAM cell, namely a magnetoresistance (MR) unit. Based on our experimental results, we conclude that this method is applicable to any MR unit with a double-hump-like hysteresis loop, especially pseudo-spin-valve magnetic tunnel junctions with a high MR ratio. Moreover, after simply reversing the correspondence between voltage signals and output logic values, this method could also be applicable to any MR unit with a double-pit-like hysteresis loop. These results may provide a helpful solution for the final commercialisation of MRAM-based stateful logic circuits in the near future.Stateful logic circuits based on next-generation nonvolatile memories, such as magnetoresistance random access memory (MRAM), promise to break the long-standing von Neumann bottleneck in state-of-the-art data processing devices. For the successful commercialisation of stateful logic circuits, a critical step is realizing the best use of a single memory cell to perform logic functions. In this work, we propose a method for implementing all 16 Boolean logic functions in a single MRAM cell, namely a magnetoresistance (MR) unit. Based on our experimental results, we conclude that this method is applicable to any MR unit with a double-hump-like hysteresis loop, especially pseudo-spin-valve magnetic tunnel junctions with a high MR ratio. Moreover, after simply reversing the correspondence between voltage signals and output logic values, this method could also be applicable to any MR unit with a double-pit-like hysteresis loop. These results may provide a helpful solution for the final commercialisation of MRAM-based stateful logic circuits in the near future. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03169b

Tuning the electronic and optical properties of NDT-based conjugated polymers by adopting fused heterocycles as acceptor units: a theoretical study.

PubMed

Cheng, Na; Zhang, Changqiao; Liu, Yongjun

2017-08-01

Donor-acceptor conjugated polymers have been successfully applied in bulk heterojunction solar cell devices. Tuning their donor and acceptor units allows the design of new polymers with desired electronic and optical properties. Here, to screen new candidate polymers based on a newly synthesized donor unit, dithieo[2,3-d:2',3'-d']naphtho[1,2-b:3,4-b']dithiophene (NDT), a series of model polymers with different acceptor units were designed and denoted NDT-A 0 to NDT-A 12 , and the structures and optical properties of those polymers were investigated using DFT and TDDFT calculations. The results of the calculations revealed that the electronic and optical properties of these polymers depend on the acceptor unit present; specifically, their HOMO energies ranged from -4.89 to -5.38 eV, their HOMO-LUMO gaps ranged from 1.30 to 2.80 eV, and their wavelengths of maximum absorption ranged from 538 to 1212 nm. The absorption spectra of NDT-A 1 to NDT-A 6 , NDT-A 8 , NDT-A 9 , and NDT-A 12 occur within the visible region (<900 nm), indicating that these polymers are potential candidates for use in solar cells. On the other hand, the absorption spectra of NDT-A 7 , NDT-A 10 , and NDT-A 11 extend much further into the near-infrared region, implying that they absorb near-infrared light. These polymers could meet the requirements of donor units for use in tandem and ternary solar cells. Graphical abstract Theoretical calculations by TD-DFT reveal that the optical properties of NDT-based conjugated polymers can be well tuned by adopting different acceptor units, and these ploymers are potential donor materials for tandem and ternary solar cells.

Analytical relationships for prediction of the mechanical properties of additively manufactured porous biomaterials.

PubMed

Zadpoor, Amir Abbas; Hedayati, Reza

2016-12-01

Recent developments in additive manufacturing techniques have motivated an increasing number of researchers to study regular porous biomaterials that are based on repeating unit cells. The physical and mechanical properties of such porous biomaterials have therefore received increasing attention during recent years. One of the areas that have revived is analytical study of the mechanical behavior of regular porous biomaterials with the aim of deriving analytical relationships that could predict the relative density and mechanical properties of porous biomaterials, given the design and dimensions of their repeating unit cells. In this article, we review the analytical relationships that have been presented in the literature for predicting the relative density, elastic modulus, Poisson's ratio, yield stress, and buckling limit of regular porous structures based on various types of unit cells. The reviewed analytical relationships are used to compare the mechanical properties of porous biomaterials based on different types of unit cells. The major areas where the analytical relationships have improved during the recent years are discussed and suggestions are made for future research directions. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 3164-3174, 2016. © 2016 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc.

A review of high-temperature polymer electrolyte membrane fuel-cell (HT-PEMFC)-based auxiliary power units for diesel-powered road vehicles

NASA Astrophysics Data System (ADS)

Liu, Yongfeng; Lehnert, Werner; Janßen, Holger; Samsun, Remzi Can; Stolten, Detlef

2016-04-01

This paper presents an extensive review of research on the development of auxiliary power units with enhanced reformate tolerance for high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Developments in diesel reforming for fuel cells as auxiliary power units (APUs), single fuel cells and stacks and systems are outlined in detail and key findings are presented. Summaries of HT-PEMFC APU applications and start-up times for HT-PEMFC systems are then given. A summary of cooling HT-PEMFC stacks using a classic schematic diagram of a 24-cell HT-PEMFC stack, with a cooling plate for every third cell, is also presented as part of a stack analysis. Finally, a summary of CO tolerances for fuel cells is given, along with the effects of different CO volume fractions on polarization curves, the fraction of CO coverage, hydrogen coverage, anode overpotential and cell potential.

Integration of red cell genotyping into the blood supply chain: a population-based study.

PubMed

Flegel, Willy A; Gottschall, Jerome L; Denomme, Gregory A

2015-07-01

When problems with compatibility arise, transfusion services often use time-consuming serological tests to identify antigen-negative red cell units for safe transfusion. New methods have made red cell genotyping possible for all clinically relevant blood group antigens. We did mass-scale genotyping of donor blood and provided hospitals with access to a large red cell database to meet the demand for antigen-negative red cell units beyond ABO and Rh blood typing. We established a red cell genotype database at the BloodCenter of Wisconsin on July 17, 2010. All self-declared African American, Asian, Hispanic, and Native American blood donors were eligible irrespective of their ABO and Rh type or history of donation. Additionally, blood donors who were groups O, A, and B, irrespective of their Rh phenotype, were eligible for inclusion only if they had a history of at least three donations in the previous 3 years, with one donation in the previous 12 months at the BloodCenter of Wisconsin. We did red cell genotyping with a nanofluidic microarray system, using 32 single nucleotide polymorphisms to predict 42 blood group antigens. An additional 14 antigens were identified via serological phenotype. We monitored the ability of the red cell genotype database to meet demand for compatible blood during 3 years. In addition to the central database at the BloodCenter of Wisconsin, we gave seven hospitals online access to a web-based antigen query portal on May 1, 2013, to help them to locate antigen-negative red cell units in their own inventories. We analysed genotype data for 43,066 blood donors. Requests were filled for 5661 (99.8%) of 5672 patient encounters in which antigen-negative red cell units were needed. Red cell genotyping met the demand for antigen-negative blood in 5339 (94.1%) of 5672 patient encounters, and the remaining 333 (5.9%) requests were filled by use of serological data. Using the 42 antigens represented in our red cell genotype database, we were able to fill 14,357 (94.8%) of 15,140 requests for antigen-negative red cell units from hospitals served by the BloodCenter of Wisconsin. In the pilot phase, the seven hospitals identified 71 units from 52 antigen-negative red cell unit requests. Red cell genotyping has the potential to transform the way antigen-negative red cell units are provided. An antigen query portal could reduce the need for transportation of blood and serological screening. If this wealth of genotype data can be made easily accessible online, it will help with the supply of affordable antigen-negative red cell units to ensure patient safety. BloodCenter of Wisconsin Diagnostic Laboratories Strategic Initiative and the NIH Clinical Center Intramural Research Program. Copyright © 2015 Elsevier Ltd. All rights reserved.

Low-reflection beam refractions by ultrathin Huygens metasurface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, Sheng Li; State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096; Synergetic Innovation Center of Wireless Communication Technology, Southeast University, Nanjing 210096

2015-06-15

We propose a Huygens source unit cell to develop an ultrathin low-reflection metasurface, which could provide extreme controls of phases of the transmitted waves. Both electric and magnetic currents are supported by the proposed unit cell, thus leading to highly efficient and full controls of phases. The coupling between electric and magnetic responses is negligible, which will significantly reduce the difficulty of design. Since the unit cell of metasurface is printed on two bonded boards, the fabrication process is simplified and the thickness of metasurface is reduced. Based on the proposed unit cell, a beam-refracting metasurface with low-reflection is designedmore » and manufactured. Both near-field and far-field characteristics of the beam-refracting metasurface are investigated by simulations and measurements, which indicate that the proposed Huygens metasurface performs well in controlling electromagnetic waves.« less

Realisation of all 16 Boolean logic functions in a single magnetoresistance memory cell.

PubMed

Gao, Shuang; Yang, Guang; Cui, Bin; Wang, Shouguo; Zeng, Fei; Song, Cheng; Pan, Feng

2016-07-07

Stateful logic circuits based on next-generation nonvolatile memories, such as magnetoresistance random access memory (MRAM), promise to break the long-standing von Neumann bottleneck in state-of-the-art data processing devices. For the successful commercialisation of stateful logic circuits, a critical step is realizing the best use of a single memory cell to perform logic functions. In this work, we propose a method for implementing all 16 Boolean logic functions in a single MRAM cell, namely a magnetoresistance (MR) unit. Based on our experimental results, we conclude that this method is applicable to any MR unit with a double-hump-like hysteresis loop, especially pseudo-spin-valve magnetic tunnel junctions with a high MR ratio. Moreover, after simply reversing the correspondence between voltage signals and output logic values, this method could also be applicable to any MR unit with a double-pit-like hysteresis loop. These results may provide a helpful solution for the final commercialisation of MRAM-based stateful logic circuits in the near future.

Location Dependency and Antenna/Body/Sensor-Lead Interaction Effects in a Cell-Phone Based GSM 1800 Telemedicine Link

DTIC Science & Technology

2001-10-25

The error-free requirement of today’s cell - phone based telemedicine systems demands investigations into the potential causes of service degradation...to the handset’s antenna can have on system performance Changes in lead orientation in the near field of the radiating unit ( cell - phone & antenna

Cord Blood Banking and Transplantation in China: A Ten Years Experience of a Single Public Bank.

PubMed

Liu, Jinhui; He, Ji; Chen, Shu; Qin, Fei; Wang, Fang; Xu, Gang; Zhu, Faming; Lv, Hangjun; Yan, Lixing

2012-02-01

BACKGROUND: Umbilical cord blood (UCB) has successfully used for transplantation to treat hematologic malignancies and genetic diseases. Herein, we describe the experience generated in a single public UCB bank at Zhejiang Province in China. METHODS: Good manufacturing practice and standard operating procedures were used to address donor selection as well as UCB collection, processing, and cryopreservation. Total nucleated cells (TNCs), cellular viability, CD34+ cells, and colony-forming units were determined, and infectious diseases screening test, sterility test, and HLA typing for UCB units were done. RESULTS: Only 18.51% of all collected UCB units met storage criteria, and 7,056 UCB units were cryopreserved in 10 years. The volume of UCB units was 95.0 ± 22.0 ml. The number of TNCs before and after processing was 13.32 ± 3.63 × 10(8) and 10.63 ± 2.80 × 10(8), respectively, and the recovery rate was 80.71 ± 11.26%. 0.4344 ± 0.1874% of the TNCs were CD34+ cells. The CFU-GM was 32.1 ± 28.0 colonies per 1 × 10(5) nucleated cells. Based mainly on HLA and nucleated cell content, 26 UCB units were released for transplantation. CONCLUSIONS: A public UCB bank was successfully established in China; collection and processing of UCB units should be optimized in order to gain maximum volume and cell count.

A neural network based computational model to predict the output power of different types of photovoltaic cells.

PubMed

Xiao, WenBo; Nazario, Gina; Wu, HuaMing; Zhang, HuaMing; Cheng, Feng

2017-01-01

In this article, we introduced an artificial neural network (ANN) based computational model to predict the output power of three types of photovoltaic cells, mono-crystalline (mono-), multi-crystalline (multi-), and amorphous (amor-) crystalline. The prediction results are very close to the experimental data, and were also influenced by numbers of hidden neurons. The order of the solar generation power output influenced by the external conditions from smallest to biggest is: multi-, mono-, and amor- crystalline silicon cells. In addition, the dependences of power prediction on the number of hidden neurons were studied. For multi- and amorphous crystalline cell, three or four hidden layer units resulted in the high correlation coefficient and low MSEs. For mono-crystalline cell, the best results were achieved at the hidden layer unit of 8.

Phononic Band Gaps in 2D Quadratic and 3D Cubic Cellular Structures

PubMed Central

Warmuth, Franziska; Körner, Carolin

2015-01-01

The static and dynamic mechanical behaviour of cellular materials can be designed by the architecture of the underlying unit cell. In this paper, the phononic band structure of 2D and 3D cellular structures is investigated. It is shown how the geometry of the unit cell influences the band structure and eventually leads to full band gaps. The mechanism leading to full band gaps is elucidated. Based on this knowledge, a 3D cellular structure with a broad full band gap is identified. Furthermore, the dependence of the width of the gap on the geometry parameters of the unit cell is presented. PMID:28793713

Phononic Band Gaps in 2D Quadratic and 3D Cubic Cellular Structures.

PubMed

Warmuth, Franziska; Körner, Carolin

2015-12-02

The static and dynamic mechanical behaviour of cellular materials can be designed by the architecture of the underlying unit cell. In this paper, the phononic band structure of 2D and 3D cellular structures is investigated. It is shown how the geometry of the unit cell influences the band structure and eventually leads to full band gaps. The mechanism leading to full band gaps is elucidated. Based on this knowledge, a 3D cellular structure with a broad full band gap is identified. Furthermore, the dependence of the width of the gap on the geometry parameters of the unit cell is presented.

Impact of the irregular microgeometry of polyurethane foam on the macroscopic acoustic behavior predicted by a unit-cell model.

PubMed

Doutres, O; Ouisse, M; Atalla, N; Ichchou, M

2014-10-01

This paper deals with the prediction of the macroscopic sound absorption behavior of highly porous polyurethane foams using two unit-cell microstructure-based models recently developed by Doutres, Atalla, and Dong [J. Appl. Phys. 110, 064901 (2011); J. Appl. Phys. 113, 054901 (2013)]. In these models, the porous material is idealized as a packing of a tetrakaidecahedra unit-cell representative of the disordered network that constitutes the porous frame. The non-acoustic parameters involved in the classical Johnson-Champoux-Allard model (i.e., porosity, airflow resistivity, tortuosity, etc.) are derived from characteristic properties of the unit-cell and semi-empirical relationships. A global sensitivity analysis is performed on these two models in order to investigate how the variability associated with the measured unit-cell characteristics affects the models outputs. This allows identification of the possible limitations of a unit-cell micro-macro approach due to microstructure irregularity. The sensitivity analysis mainly shows that for moderately and highly reticulated polyurethane foams, the strut length parameter is the key parameter since it greatly impacts three important non-acoustic parameters and causes large uncertainty on the sound absorption coefficient even if its measurement variability is moderate. For foams with a slight inhomogeneity and anisotropy, a micro-macro model associated to cell size measurements should be preferred.

An Electron-Deficient Building Block Based on the B←N Unit: An Electron Acceptor for All-Polymer Solar Cells.

PubMed

Dou, Chuandong; Long, Xiaojing; Ding, Zicheng; Xie, Zhiyuan; Liu, Jun; Wang, Lixiang

2016-01-22

A double B←N bridged bipyridyl (BNBP) is a novel electron-deficient building block for polymer electron acceptors in all-polymer solar cells. The B←N bridging units endow BNBP with fixed planar configuration and low-lying LUMO/HOMO energy levels. As a result, the polymer based on BNBP units (P-BNBP-T) exhibits high electron mobility, low-lying LUMO/HOMO energy levels, and strong absorbance in the visible region, which is desirable for polymer electron acceptors. Preliminary all-polymer solar cell (all-PSC) devices with P-BNBP-T as the electron acceptor and PTB7 as the electron donor exhibit a power conversion efficiency (PCE) of 3.38%, which is among the highest values of all-PSCs with PTB7 as the electron donor. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A portable liquid crystal-based polarized light system for the detection of organophosphorus nerve gas.

PubMed

He, Feng Jie; Liu, Hui Long; Chen, Long Cong; Xiong, Xing Liang

2018-03-01

Liquid crystal (LC)-based sensors have the advantageous properties of being fast, sensitive, and label-free, the results of which can be accessed directly only through the naked eye. However, the inherent disadvantages possessed by LC sensors, such as relying heavily on polarizing microscopes and the difficulty to quantify, have limited the possibility of field applications. Herein, we have addressed these issues by constructing a portable polarized detection system with constant temperature control. This system is mainly composed of four parts: the LC cell, the optics unit, the automatic temperature control unit, and the image processing unit. The LC cell was based on the ordering transitions of LCs in the presence of analytes. The optics unit based on the imaging principle of LCs was designed to substitute the polarizing microscope for the real-time observation. The image processing unit is expected to quantify the concentration of analytes. The results have shown that the presented system can detect dimethyl methyl phosphonate (a stimulant for organophosphorus nerve gas) within 25 s, and the limit of detection is about 10 ppb. In all, our portable system has potential in field applications.

A portable liquid crystal-based polarized light system for the detection of organophosphorus nerve gas

NASA Astrophysics Data System (ADS)

He, Feng Jie; Liu, Hui Long; Chen, Long Cong; Xiong, Xing Liang

2018-03-01

Liquid crystal (LC)-based sensors have the advantageous properties of being fast, sensitive, and label-free, the results of which can be accessed directly only through the naked eye. However, the inherent disadvantages possessed by LC sensors, such as relying heavily on polarizing microscopes and the difficulty to quantify, have limited the possibility of field applications. Herein, we have addressed these issues by constructing a portable polarized detection system with constant temperature control. This system is mainly composed of four parts: the LC cell, the optics unit, the automatic temperature control unit, and the image processing unit. The LC cell was based on the ordering transitions of LCs in the presence of analytes. The optics unit based on the imaging principle of LCs was designed to substitute the polarizing microscope for the real-time observation. The image processing unit is expected to quantify the concentration of analytes. The results have shown that the presented system can detect dimethyl methyl phosphonate (a stimulant for organophosphorus nerve gas) within 25 s, and the limit of detection is about 10 ppb. In all, our portable system has potential in field applications.

A new metamaterial-based wideband rectangular invisibility cloak

NASA Astrophysics Data System (ADS)

Islam, S. S.; Hasan, M. M.; Faruque, M. R. I.

2018-02-01

A new metamaterial-based wideband electromagnetic rectangular cloak is being introduced in this study. The metamaterial unit cell shows sharp transmittances in the C- and X-bands and displays wideband negative effective permittivity region there. The metamaterial unit cell was then applied in designing a rectangular-shaped electromagnetic cloak. The scattering reduction technique was adopted for the cloaking operation. The cloak operates in the certain portion of C-and X-bands that covers more than 4 GHz bandwidth region. The experimental results were provided as well for the metamaterial and the cloak.

Auxiliary power unit based on a solid oxide fuel cell and fuelled with diesel

NASA Astrophysics Data System (ADS)

Lawrence, Jeremy; Boltze, Matthias

An auxiliary power unit (APU) is presented that is fuelled with diesel, thermally self-sustaining, and based on a solid oxide fuel cell (SOFC). The APU is rated at 1 kW electrical, and can generate electrical power after a 3 h warm-up phase. System features include a "dry" catalytic partial oxidation (CPOX) diesel reformer, a 30 cell SOFC stack with an open cathode, and a porous-media afterburner. The APU does not require a supply of external water. The SOFC stack is an outcome of a development partnership with H.C. Starck GmbH and Fraunhofer IKTS, and is discussed in detail in an accompanying paper.

Lightweight Solar Photovoltaic Blankets

NASA Technical Reports Server (NTRS)

Ceragioli, R.; Himmler, R.; Nath, P.; Vogeli, C.; Guha, S.

1995-01-01

Lightweight, flexible sheets containing arrays of stacked solar photovoltaic cells developed to supply electric power aboard spacecraft. Solar batteries satisfying stringent requirements for operation in outer space also adaptable to terrestrial environment. Attractive for use as long-lived, portable photovoltaic power sources. Cells based on amorphous silicon which offers potential for order-of-magnitude increases in power per unit weight, power per unit volume, and endurance in presence of ionizing radiation.

Novel web-based real-time dashboard to optimize recycling and use of red cell units at a large multi-site transfusion service.

PubMed

Sharpe, Christopher; Quinn, Jason G; Watson, Stephanie; Doiron, Donald; Crocker, Bryan; Cheng, Calvino

2014-01-01

Effective blood inventory management reduces outdates of blood products. Multiple strategies have been employed to reduce the rate of red blood cell (RBC) unit outdate. We designed an automated real-time web-based dashboard interfaced with our laboratory information system to effectively recycle red cell units. The objective of our approach is to decrease RBC outdate rates within our transfusion service. The dashboard was deployed in August 2011 and is accessed by a shortcut that was placed on the desktops of all blood transfusion services computers in the Capital District Health Authority region. It was designed to refresh automatically every 10 min. The dashboard provides all vital information on RBC units, and implemented a color coding scheme to indicate an RBC unit's proximity to expiration. The overall RBC unit outdate rate in the 7 months period following implementation of the dashboard (September 2011-March 2012) was 1.24% (123 units outdated/9763 units received), compared to similar periods in 2010-2011 and 2009-2010: 2.03% (188/9395) and 2.81% (261/9220), respectively. The odds ratio of a RBC unit outdate postdashboard (2011-2012) compared with 2010-2011 was 0.625 (95% confidence interval: 0.497-0.786; P < 0.0001). Our dashboard system is an inexpensive and novel blood inventory management system which was associated with a significant reduction in RBC unit outdate rates at our institution over a period of 7 months. This system, or components of it, could be a useful addition to existing RBC management systems at other institutions.

Theoretical characterization and design of small molecule donor material containing naphthodithiophene central unit for efficient organic solar cells.

PubMed

Duan, Yu-Ai; Geng, Yun; Li, Hai-Bin; Jin, Jun-Ling; Wu, Yong; Su, Zhong-Min

2013-07-15

To seek for high-performance small molecule donor materials used in heterojunction solar cell, six acceptor-donor-acceptor small molecules based on naphtho[2,3-b:6,7-b']dithiophene (NDT) units with different acceptor units were designed and characterized using density functional theory and time-dependent density functional theory. Their geometries, electronic structures, photophysical, and charge transport properties have been scrutinized comparing with the reported donor material NDT(TDPP)2 (TDPP  =  thiophene-capped diketopyrrolopyrrole). The open circuit voltage (V(oc)), energetic driving force(ΔE(L-L)), and exciton binding energy (E(b)) were also provided to give an elementary understanding on their cell performance. The results reveal that the frontier molecular orbitals of 3-7 match well with the acceptor material PC61 BM, and compounds 3-5 were found to exhibit the comparable performances to 1 and show promising potential in organic solar cells. In particular, comparing with 1, system 7 with naphthobisthiadiazole acceptor unit displays broader absorption spectrum, higher V(oc), lower E(b), and similar carrier mobility. An in-depth insight into the nature of the involved excited states based on transition density matrix and charge density difference indicates that all S1 states are mainly intramolecular charge transfer states with the charge transfer from central NDT unit to bilateral acceptor units, and also imply that the exciton of 7 can be dissociated easily due to its large extent of the charge transfer. In a word, 7 maybe superior to 1 and may act as a promising donor candidate for organic solar cell. Copyright © 2013 Wiley Periodicals, Inc.

A crypto-lymphatic unit at the uvula of the monkey Macaca fascicularis. A light- and electron-microscopic study.

PubMed

Nair, P N

1983-01-01

A crypto-lymphatic unit was observed at the left lateral aspect of the uvula of a mature female monkey, Macaca fascicularis. A light- and transmission electron-microscopic investigation revealed that the lumen of the crypt was filled with bacteria, desquamated epithelial cells, lymphocytes and neutrophils. The non-keratinized stratified squamous epithelium of the crypt was fragmented and showed heavy mononuclear cell infiltration and surface discontinuities, exposing lymphoid cells to foreign material. The lymphatic parenchyma consisted of organized lymphatic tissue including germinal centres. The resident cell population included lymphocytes of varying size, blastforming B- and T-lymphocytes and two types of reticular cells resembling the fibroblastic reticulum cell and the follicular dendritic cell, respectively. Occasionally granulocytes were encountered. At its base and laterally the crypto-lymphatic unit was ensheathed by a thin connective tissue capsule. Three other monkeys of the same species failed to reveal similar structures at the same site.

Modelling and simulation of a robotic work cell

NASA Astrophysics Data System (ADS)

Sękala, A.; Gwiazda, A.; Kost, G.; Banaś, W.

2017-08-01

The subject of considerations presented in this work concerns the designing and simulation of a robotic work cell. The designing of robotic cells is the process of synergistic combining the components in the group, combining this groups into specific, larger work units or dividing the large work units into small ones. Combinations or divisions are carried out in the terms of the needs of realization the assumed objectives to be performed in these unit. The designing process bases on the integrated approach what lets to take into consideration all needed elements of this process. Each of the elements of a design process could be an independent design agent which could tend to obtain its objectives.

Feed-forward control of a solid oxide fuel cell system with anode offgas recycle

NASA Astrophysics Data System (ADS)

Carré, Maxime; Brandenburger, Ralf; Friede, Wolfgang; Lapicque, François; Limbeck, Uwe; da Silva, Pedro

2015-05-01

In this work a combined heat and power unit (CHP unit) based on the solid oxide fuel cell (SOFC) technology is analysed. This unit has a special feature: the anode offgas is partially recycled to the anode inlet. Thus it is possible to increase the electrical efficiency and the system can be operated without external water feeding. A feed-forward control concept which allows secure operating conditions of the CHP unit as well as a maximization of its electrical efficiency is introduced and validated experimentally. The control algorithm requires a limited number of measurement values and few deterministic relations for its description.

Design and optimization of membrane-type acoustic metamaterials

NASA Astrophysics Data System (ADS)

Blevins, Matthew Grant

One of the most common problems in noise control is the attenuation of low frequency noise. Typical solutions require barriers with high density and/or thickness. Membrane-type acoustic metamaterials are a novel type of engineered material capable of high low-frequency transmission loss despite their small thickness and light weight. These materials are ideally suited to applications with strict size and weight limitations such as aircraft, automobiles, and buildings. The transmission loss profile can be manipulated by changing the micro-level substructure, stacking multiple unit cells, or by creating multi-celled arrays. To date, analysis has focused primarily on experimental studies in plane-wave tubes and numerical modeling using finite element methods. These methods are inefficient when used for applications that require iterative changes to the structure of the material. To facilitate design and optimization of membrane-type acoustic metamaterials, computationally efficient dynamic models based on the impedance-mobility approach are proposed. Models of a single unit cell in a waveguide and in a baffle, a double layer of unit cells in a waveguide, and an array of unit cells in a baffle are studied. The accuracy of the models and the validity of assumptions used are verified using a finite element method. The remarkable computational efficiency of the impedance-mobility models compared to finite element methods enables implementation in design tools based on a graphical user interface and in optimization schemes. Genetic algorithms are used to optimize the unit cell design for a variety of noise reduction goals, including maximizing transmission loss for broadband, narrow-band, and tonal noise sources. The tools for design and optimization created in this work will enable rapid implementation of membrane-type acoustic metamaterials to solve real-world noise control problems.

Long-range, full-duplex, modulated-reflector cell phone for voice/data transmission

DOEpatents

Neagley, Daniel L.; Briles, Scott D.; Coates, Don M.; Freund, Samuel M.

2002-01-01

A long-range communications apparatus utilizing modulated-reflector technology is described. The apparatus includes an energy-transmitting base station and remote units that do not emit radiation in order to communicate with the base station since modulated-reflector technology is used whereby information is attached to an RF carrier wave originating from the base station which is reflected by the remote unit back to the base station. Since the remote unit does not emit radiation, only a low-power power source is required for its operation. Information from the base station is transmitted to the remote unit using a transmitter and receiver, respectively. The range of such a communications system is determined by the properties of a modulated-reflector half-duplex link.

Backscattered EM-wave manipulation using low cost 1-bit reflective surface at W-band

NASA Astrophysics Data System (ADS)

Taher Al-Nuaimi, Mustafa K.; Hong, Wei; He, Yejun

2018-04-01

The design of low cost 1-bit reflective (non-absorptive) surfaces for manipulation of backscattered EM-waves and radar cross section (RCS) reduction at W-band is presented in this article. The presented surface is designed based on the reflection phase cancellation principle. The unit cell used to compose the proposed surface has an obelus (division symbol of short wire and two disks above and below) like shape printed on a grounded dielectric material. Using this unit cell, surfaces that can efficiently manipulate the backscattered RCS pattern by using the proposed obelus-shaped unit cell (as ‘0’ element) and its mirrored unit cell (as ‘1’ element) in one surface with a 180°  ±  35° reflection phase difference between their reflection phases are designed. The proposed surfaces can generate various kinds of backscattered RCS patterns, such as single, three, or four lobes or even a low-level (reduced RCS) diffused reflection pattern when those two unit cells are distributed randomly across the surface aperture. For experimental characterization purposes, a 50  ×  50 mm2 surface is fabricated and measured.

Thermoviscoplastic analysis of fibrous periodic composites using triangular subvolumes

NASA Technical Reports Server (NTRS)

Walker, Kevin P.; Freed, Alan D.; Jordan, Eric H.

1993-01-01

The nonlinear viscoplastic behavior of fibrous periodic composites is analyzed by discretizing the unit cell into triangular subvolumes. A set of these subvolumes can be configured by the analyst to construct a representation for the unit cell of a periodic composite. In each step of the loading history, the total strain increment at any point is governed by an integral equation which applies to the entire composite. A Fourier series approximation allows the incremental stresses and strains to be determined within a unit cell of the periodic lattice. The nonlinearity arising from the viscoplastic behavior of the constituent materials comprising the composite is treated as fictitious body force in the governing integral equation. Specific numerical examples showing the stress distributions in the unit cell of a fibrous tungsten/copper metal matrix composite under viscoplastic loading conditions are given. The stress distribution resulting in the unit cell when the composite material is subjected to an overall transverse stress loading history perpendicular to the fibers is found to be highly heterogeneous, and typical homogenization techniques based on treating the stress and strain distributions within the constituent phases as homogeneous result in large errors under inelastic loading conditions.

Thermoviscoplastic analysis of fibrous periodic composites by the use of triangular subvolumes

NASA Technical Reports Server (NTRS)

Walker, Kevin P.; Freed, Alan D.; Jordan, Eric H.

1994-01-01

The non-linear viscoplastic behavior of fibrous periodic composites is analyzed by discretizing the unit cell into triangular subvolumes. A set of these subvolumes can be configured by the analyst to construct a representation for the unit cell of a periodic composite. In each step of the loading history the total strain increment at any point is governed by an integral equation which applies to the entire composite. A Fourier series approximation allows the incremental stresses and strains to be determined within a unit cell of the periodic lattice. The non-linearity arising from the viscoplastic behavior of the constituent materials comprising the composite is treated as a fictitious body force in the governing integral equation. Specific numerical examples showing the stress distributions in the unit cell of a fibrous tungsten/copper metal-matrix composite under viscoplastic loading conditions are given. The stress distribution resulting in the unit cell when the composite material is subjected to an overall transverse stress loading history perpendicular to the fibers is found to be highly heterogeneous, and typical homogenization techniques based on treating the stress and strain distributions within the constituent phases as homogeneous result in large errors under inelastic loading conditions.

Mechanisms of efferent-mediated responses in the turtle posterior crista.

PubMed

Holt, Joseph C; Lysakowski, Anna; Goldberg, Jay M

2006-12-20

To study the cellular mechanisms of efferent actions, we recorded from vestibular-nerve afferents close to the turtle posterior crista while efferent fibers were electrically stimulated. Efferent-mediated responses were obtained from calyx-bearing (CD, calyx and dimorphic) afferents and from bouton (B) afferents distinguished by their neuroepithelial locations into BT units near the torus and BM units at intermediate sites. The spike discharge of CD units is strongly excited by efferent stimulation, whereas BT and BM units are inhibited, with BM units also showing a postinhibitory excitation. Synaptic activity was recorded intracellularly after spikes were blocked. Responses of BT/BM units to single efferent shocks consist of a brief depolarization followed by a prolonged hyperpolarization. Both components reflect variations in hair-cell quantal release rates and are eliminated by pharmacological antagonists of alpha9/alpha10 nicotinic receptors. Blocking calcium-dependent SK potassium channels converts the biphasic response into a prolonged depolarization. Results can be explained, as in other hair-cell systems, by the sequential activation of alpha9/alpha10 and SK channels. In BM units, the postinhibitory excitation is based on an increased rate of hair-cell quanta and depends on the preceding inhibition. There is, in addition, an efferent-mediated, direct depolarization of BT/BM and CD fibers. In CD units, it is the exclusive efferent response. Nicotinic antagonists have different effects on hair-cell efferent actions and on the direct depolarization of CD and BT/BM units. Ultrastructural studies, besides confirming the efferent innervation of type II hair cells and calyx endings, show that turtle efferents commonly contact afferent boutons terminating on type II hair cells.

Assembly of hydrogel units for 3D microenvironment in a poly(dimethylsiloxane) channel

NASA Astrophysics Data System (ADS)

Cho, Chang Hyun; Kwon, Seyong; Park, Je-Kyun

2017-12-01

Construction of three-dimensional (3D) microenvironment become an important issue in recent biological studies due to their biological relevance compared to conventional two-dimensional (2D) microenvironment. Various fabrication techniques have been employed to construct a 3D microenvironment, however, it is difficult to fully satisfy the biological and mechanical properties required for the 3D cell culture system, such as heterogeneous tissue structures generated from the functional differences or diseases. We propose here an assembly method for facile construction of 3D microenvironment in a poly(dimethylsiloxane) (PDMS) channel using hydrogel units. The high-aspect-ratio of hydrogel units was achieved by fabricating these units using a 2D mold. With this approach, 3D heterogeneous hydrogel units were produced and assembled in a PDMS channel by structural hookup. In vivo-like 3D heterogeneous microenvironment in a precisely controllable fluidic system was also demonstrated using a controlled assembly of different types of hydrogel units, which was difficult to obtain from previous methods. By regulating the flow condition, the mechanical stability of the assembled hydrogel units was verified by the flow-induced deformation of hydrogel units. In addition, in vivo-like cell culture environment was demonstrated using an assembly of cell-coated hydrogel units in the fluidic channel. Based on these features, our method expects to provide a beneficial tool for the 3D cell culture module and biomimetic engineering.

Methodology for the Determination of the Photon Detection Efficiency of Large-Area Multi-Pixel Photon Counters

NASA Astrophysics Data System (ADS)

Beattie, T.; Lolos, G. J.; Papandreou, Z.; Semenov, A. Yu.; Teigrob, L. A.

2015-08-01

Large-area, multi-pixel photon counters will be used for the electromagnetic Barrel Calorimeter of the GlueX experiment at Jefferson Lab. These photo sensors are based on a 3 ×3 mm2 cell populated by 50 μm pixels, with 16 such cells tiled in a 4 ×4 arrangement in the array. The 16 cells are summed electronically and the signals are amplified. The photon detection efficiency of a group of first-article units at room temperature under conditions similar to those of the experiment was extracted to be (28 ±2(stat) ±2(syst))%, by employing an analysis methodology based on Poisson statistics carried out on the summed energy signals from the units.

The Applicability of the Generalized Method of Cells for Analyzing Discontinuously Reinforced Composites

NASA Technical Reports Server (NTRS)

Pahr, D. H.; Arnold, S. M.

2001-01-01

The paper begins with a short overview of the recent work done in the field of discontinuous reinforced composites, focusing on the different parameters which influence the material behavior of discontinuous reinforced composites, as well as the various analysis approaches undertaken. Based on this overview it became evident, that in order to investigate the enumerated effects in an efficient and comprehensive manner, an alternative approach to the computationally intensive finite-element based micromechanics approach is required. Therefore, an investigation is conducted to demonstrate the utility of utilizing the generalized method of cells (GMC), a semi-analytical micromechanics-based approach, to simulate the elastic and elastoplastic material behavior of aligned short fiber composites. The results are compared with (1) simulations using other micromechanical based mean field models and finite element (FE) unit cell models found in the literature given elastic material behavior, as well as (2) finite element unit cell and a new semianalytical elastoplastic shear lag model in the inelastic range. GMC is shown to definitely have a window of applicability when simulating discontinuously reinforced composite material behavior.

The Applicability of the Generalized Method of Cells for Analyzing Discontinuously Reinforced Composites

NASA Technical Reports Server (NTRS)

Pahr, D. H.; Arnold, S. M.

2001-01-01

The paper begins with a short overview of the recent work done in the field of discontinuous reinforced composites, focusing on the different parameters which influence the material behavior of discontinuous reinforced composites, as well as the various analysis approaches undertaken. Based on this overview it became evident that in order to investigate the enumerated effects in an efficient and comprehensive manner, an alternative approach to the computationally intensive finite-element based micromechanics approach is required. Therefore, an investigation is conducted to demonstrate the utility of utilizing the generalized method of cells (GMC), a semi-analytical micromechanics-based approach, to simulate the elastic and elastoplastic material behavior of aligned short fiber composites. The results are compared with simulations using other micromechanical based mean field models and finite element (FE) unit cell models found in the literature given elastic material behavior, as well as finite element unit cell and a new semianalytical elastoplastic shear lag model in the inelastic range. GMC is shown to definitely have a window of applicability when simulating discontinuously reinforced composite material behavior.

Modeling potential Emerald Ash Borer spread through GIS/cell-based/gravity models with data bolstered by web-based inputs

Treesearch

Louis R. Iverson; Anantha M. Prasad; Davis Sydnor; Jonathan Bossenbroek; Mark W. Schwartz; Mark W. Schwartz

2006-01-01

We model the susceptibility and potential spread of the organism across the eastern United States and especially through Michigan and Ohio using Forest Inventory and Analysis (FIA) data. We are also developing a cell-based model for the potential spread of the organism. We have developed a web-based tool for public agencies and private individuals to enter the...

A Micromechanics Finite Element Model for Studying the Mechanical Behavior of Spray-On Foam Insulation (SOFI)

NASA Technical Reports Server (NTRS)

Ghosn, Louis J.; Sullivan, Roy M.; Lerch, Bradley A.

2006-01-01

A micromechanics model has been constructed to study the mechanical behavior of spray-on foam insulation (SOFI) for the external tank. The model was constructed using finite elements representing the fundamental repeating unit of the SOFI microstructure. The details of the micromechanics model were based on cell observations and measured average cell dimensions discerned from photomicrographs. The unit cell model is an elongated Kelvin model (fourteen-sided polyhedron with 8 hexagonal and six quadrilateral faces), which will pack to a 100% density. The cell faces and cell edges are modeled using three-dimensional 20-node brick elements. Only one-eighth of the cell is modeled due to symmetry. By exercising the model and correlating the results with the macro-mechanical foam behavior obtained through material characterization testing, the intrinsic stiffness and Poisson s Ratio of the polymeric cell walls and edges are determined as a function of temperature. The model is then exercised to study the unique and complex temperature-dependent mechanical behavior as well as the fracture initiation and propagation at the microscopic unit cell level.

Production, purification and preliminary X-ray crystallographic studies of adeno-associated virus serotype 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Edward B.; Gurda-Whitaker, Brittney; Govindasamy, Lakshmanan

2006-12-01

Crystals of baculovirus-expressed adeno-associated virus serotype 1 (AAV1) capsids have been grown in the rhombohedral space group R32 (unit-cell parameters a = 254.7 Å, α = 62.3°) and shown to diffract X-rays to at least 2.5 Å resolution. Crystals of baculovirus-expressed adeno-associated virus serotype 1 (AAV1) capsids have been grown in the rhombohedral space group R32 (unit-cell parameters a = 254.7 Å, α = 62.3°) and shown to diffract X-rays to at least 2.5 Å resolution. The diffraction data were subsequently processed and reduced with an overall R{sub sym} of 12.3% and a completeness of 89.0%. Based on the unit-cellmore » volume, rotation-function and translation-function results and packing considerations, there is one virus capsid (60 viral proteins) per unit cell and there are ten viral proteins per crystallographic asymmetric unit. The AAV1 capsid shares both the twofold and threefold crystallographic symmetry operators. The AAV1 data have been initially phased using a polyalanine model (based on the crystal structure of AAV4) to 4.0 Å resolution and the structure determination and refinement is in progress using tenfold noncrystallographic symmetry electron-density averaging.« less

Preparation and analysis of fetal liver extracts.

PubMed

Zwicky, C; Gerber, S; Gasparini, D; Forestier, F; Hohlfeld, P; Tissot, J D; Schneider, P

2000-09-01

The aim of this work is to describe the techniques that have been used for preparation and analysis of whole fetal liver extracts destined for in utero transplantation. Nine fetal livers between 12 and 17 weeks of gestation were prepared: cell counts and assessment of the hematopoietic cell viability were performed on cell suspensions. Hepatocytes represented 40 to 80% of the whole cell population. The remaining cells were constituted by hematopoietic cells (mainly erythroblasts), as well as by endothelial cells. The latter expressed CD34 on their surface, interfering with the assessment of CD34+ hematopoietic cells by flow cytometry. Direct visual morphologic control using alkaline phosphatase anti-alkaline phosphatase techniques was needed to differentiate hematopoietic from extra-hematopoietic CD34+ cells. Between 3.0 and 34.6 x 10(6) CD34+ viable hematopoietic cells were collected per fetal liver. Adequate differentiation of these cells into burst-forming units erythroid (BFU-E), colony-forming units granulocyte-macrophage (CFU-GM), and colony-forming units granulocyte erythroid macrophage megakaryocyte (CFU-GEMM) has been shown for each sample in clonogeneic cultures. In conclusion, fetal liver is a potential source of hematopoietic stem cells. Their numeration, based on the presence of CD34, is hampered by the expression of this antigen on other cells contained in the liver cell extract, in particular endothelial cells.

On the Finite Element Implementation of the Generalized Method of Cells Micromechanics Constitutive Model

NASA Technical Reports Server (NTRS)

Wilt, T. E.

1995-01-01

The Generalized Method of Cells (GMC), a micromechanics based constitutive model, is implemented into the finite element code MARC using the user subroutine HYPELA. Comparisons in terms of transverse deformation response, micro stress and strain distributions, and required CPU time are presented for GMC and finite element models of fiber/matrix unit cell. GMC is shown to provide comparable predictions of the composite behavior and requires significantly less CPU time as compared to a finite element analysis of the unit cell. Details as to the organization of the HYPELA code are provided with the actual HYPELA code included in the appendix.

Droplet Array-Based 3D Coculture System for High-Throughput Tumor Angiogenesis Assay.

PubMed

Du, Xiaohui; Li, Wanming; Du, Guansheng; Cho, Hansang; Yu, Min; Fang, Qun; Lee, Luke P; Fang, Jin

2018-03-06

Angiogenesis is critical for tumor progression and metastasis, and it progresses through orchestral multicellular interactions. Thus, there is urgent demand for high-throughput tumor angiogenesis assays for concurrent examination of multiple factors. For investigating tumor angiogenesis, we developed a microfluidic droplet array-based cell-coculture system comprising a two-layer polydimethylsiloxane chip featuring 6 × 9 paired-well arrays and an automated droplet-manipulation device. In each droplet-pair unit, tumor cells were cultured in 3D in one droplet by mixing cell suspensions with Matrigel, and in the other droplet, human umbilical vein endothelial cells (HUVECs) were cultured in 2D. Droplets were fused by a newly developed fusion method, and tumor angiogenesis was assayed by coculturing tumor cells and HUVECs in the fused droplet units. The 3D-cultured tumor cells formed aggregates harboring a hypoxic center-as observed in vivo-and secreted more vascular endothelial growth factor (VEGF) and more strongly induced HUVEC tubule formation than did 2D-cultured tumor cells. Our single array supported 54 assays in parallel. The angiogenic potentials of distinct tumor cells and their differential responses to antiangiogenesis agent, Fingolimod, could be investigated without mutual interference in a single array. Our droplet-based assay is convenient to evaluate multicellular interaction in high throughput in the context of tumor sprouting angiogenesis, and we envision that the assay can be extensively implementable for studying other cell-cell interactions.

Influence of yield surface curvature on the macroscopic yielding and ductile failure of isotropic porous plastic materials

NASA Astrophysics Data System (ADS)

Dæhli, Lars Edvard Bryhni; Morin, David; Børvik, Tore; Hopperstad, Odd Sture

2017-10-01

Numerical unit cell models of an approximative representative volume element for a porous ductile solid are utilized to investigate differences in the mechanical response between a quadratic and a non-quadratic matrix yield surface. A Hershey equivalent stress measure with two distinct values of the yield surface exponent is employed as the matrix description. Results from the unit cell calculations are further used to calibrate a heuristic extension of the Gurson model which incorporates effects of the third deviatoric stress invariant. An assessment of the porous plasticity model reveals its ability to describe the unit cell response to some extent, however underestimating the effect of the Lode parameter for the lower triaxiality ratios imposed in this study when compared to unit cell simulations. Ductile failure predictions by means of finite element simulations using a unit cell model that resembles an imperfection band are then conducted to examine how the non-quadratic matrix yield surface influences the failure strain as compared to the quadratic matrix yield surface. Further, strain localization predictions based on bifurcation analyses and imperfection band analyses are undertaken using the calibrated porous plasticity model. These simulations are then compared to the unit cell calculations in order to elucidate the differences between the various modelling strategies. The current study reveals that strain localization analyses using an imperfection band model and a spatially discretized unit cell are in reasonable agreement, while the bifurcation analyses predict higher strain levels at localization. Imperfection band analyses are finally used to calculate failure loci for the quadratic and the non-quadratic matrix yield surface under a wide range of loading conditions. The underlying matrix yield surface is demonstrated to have a pronounced influence on the onset of strain localization.

Family cord blood banking for sickle cell disease: a twenty-year experience in two dedicated public cord blood banks

PubMed Central

Rafii, Hanadi; Bernaudin, Françoise; Rouard, Helene; Vanneaux, Valérie; Ruggeri, Annalisa; Cavazzana, Marina; Gauthereau, Valerie; Stanislas, Aurélie; Benkerrou, Malika; De Montalembert, Mariane; Ferry, Christele; Girot, Robert; Arnaud, Cecile; Kamdem, Annie; Gour, Joelle; Touboul, Claudine; Cras, Audrey; Kuentz, Mathieu; Rieux, Claire; Volt, Fernanda; Cappelli, Barbara; Maio, Karina T.; Paviglianiti, Annalisa; Kenzey, Chantal; Larghero, Jerome; Gluckman, Eliane

2017-01-01

Efforts to implement family cord blood banking have been developed in the past decades for siblings requiring stem cell transplantation for conditions such as sickle cell disease. However, public banks are faced with challenging decisions about the units to be stored, discarded, or used for other endeavors. We report here 20 years of experience in family cord blood banking for sickle cell disease in two dedicated public banks. Participants were pregnant women who had a previous child diagnosed with homozygous sickle cell disease. Participation was voluntary and free of charge. All mothers underwent mandatory serological screening. Cord blood units were collected in different hospitals, but processed and stored in two public banks. A total of 338 units were stored for 302 families. Median recipient age was six years (11 months-15 years). Median collected volume and total nucleated cell count were 91 mL (range 23–230) and 8.6×108 (range 0.7–75×108), respectively. Microbial contamination was observed in 3.5% (n=12), positive hepatitis B serology in 25% (n=84), and homozygous sickle cell disease in 11% (n=37) of the collections. Forty-four units were HLA-identical to the intended recipient, and 28 units were released for transplantation either alone (n=23) or in combination with the bone marrow from the same donor (n=5), reflecting a utilization rate of 8%. Engraftment rate was 96% with 100% survival. Family cord blood banking yields good quality units for sibling transplantation. More comprehensive banking based on close collaboration among banks, clinical and transplant teams is recommended to optimize the use of these units. PMID:28302713

Family cord blood banking for sickle cell disease: a twenty-year experience in two dedicated public cord blood banks.

PubMed

Rafii, Hanadi; Bernaudin, Françoise; Rouard, Helene; Vanneaux, Valérie; Ruggeri, Annalisa; Cavazzana, Marina; Gauthereau, Valerie; Stanislas, Aurélie; Benkerrou, Malika; De Montalembert, Mariane; Ferry, Christele; Girot, Robert; Arnaud, Cecile; Kamdem, Annie; Gour, Joelle; Touboul, Claudine; Cras, Audrey; Kuentz, Mathieu; Rieux, Claire; Volt, Fernanda; Cappelli, Barbara; Maio, Karina T; Paviglianiti, Annalisa; Kenzey, Chantal; Larghero, Jerome; Gluckman, Eliane

2017-06-01

Efforts to implement family cord blood banking have been developed in the past decades for siblings requiring stem cell transplantation for conditions such as sickle cell disease. However, public banks are faced with challenging decisions about the units to be stored, discarded, or used for other endeavors. We report here 20 years of experience in family cord blood banking for sickle cell disease in two dedicated public banks. Participants were pregnant women who had a previous child diagnosed with homozygous sickle cell disease. Participation was voluntary and free of charge. All mothers underwent mandatory serological screening. Cord blood units were collected in different hospitals, but processed and stored in two public banks. A total of 338 units were stored for 302 families. Median recipient age was six years (11 months-15 years). Median collected volume and total nucleated cell count were 91 mL (range 23-230) and 8.6×10 8 (range 0.7-75×10 8 ), respectively. Microbial contamination was observed in 3.5% (n=12), positive hepatitis B serology in 25% (n=84), and homozygous sickle cell disease in 11% (n=37) of the collections. Forty-four units were HLA-identical to the intended recipient, and 28 units were released for transplantation either alone (n=23) or in combination with the bone marrow from the same donor (n=5), reflecting a utilization rate of 8%. Engraftment rate was 96% with 100% survival. Family cord blood banking yields good quality units for sibling transplantation. More comprehensive banking based on close collaboration among banks, clinical and transplant teams is recommended to optimize the use of these units. Copyright© Ferrata Storti Foundation.

Basolateral membrane Na/base cotransport is dependent on CO2/HCO3 in the proximal convoluted tubule

PubMed Central

1987-01-01

The mechanism of basolateral membrane base transport was examined in the in vitro microperfused rabbit proximal convoluted tubule (PCT) in the absence and presence of ambient CO2/HCO3- by means of the microfluorometric measurement of cell pH. The buffer capacity of the cells measured using rapid NH3 washout was 42.8 +/- 5.6 mmol.liter-1.pH unit-1 in the absence and 84.6 +/- 7.3 mmol.liter-1.pH unit-1 in the presence of CO2/HCO3-. In the presence of CO2/HCO3-, lowering peritubular pH from 7.4 to 6.8 acidified the cell by 0.30 pH units and lowering peritubular Na from 147 to 0 mM acidified the cell by 0.25 pH units. Both effects were inhibited by peritubular 4-acetamido-4'- isothiocyanostilbene-2,2'-disulfonate (SITS). In the absence of exogenous CO2/HCO3-, lowering peritubular pH from 7.4 to 6.8 acidified the cell by 0.25 pH units and lowering peritubular Na from 147 to 0 mM decreased cell pH by 0.20 pH units. Lowering bath pH from 7.4 to 6.8 induced a proton flux of 643 +/- 51 pmol.mm-1.min-1 in the presence of exogenous CO2/HCO3- and 223 +/- 27 pmol.mm-1.min-1 in its absence. Lowering bath Na from 147 to 0 mM induced proton fluxes of 596 +/- 77 pmol.mm-1.min-1 in its absence. The cell acidification induced by lowering bath pH or bath Na in the absence of CO2/HCO3- was inhibited by peritubular SITS or by acetazolamide, whereas peritubular amiloride had no effect. In the absence of exogenous CO2/HCO3-, cyanide blocked the cell acidification induced by bath Na removal, but was without effect in the presence of exogenous CO2/HCO3-. We reached the following conclusions. (a) The basolateral Na/base n greater than 1 cotransporter in the rabbit PCT has an absolute requirement for CO2/HCO3-. (b) In spite of this CO2 dependence, in the absence of exogenous CO2/HCO3-, metabolically produced CO2/HCO3- is sufficient to keep the transporter running at 30% of its control rate in the presence of ambient CO2/HCO3- . (c) There is no apparent amiloride-sensitive Na/H antiporter on the basolateral membrane of the rabbit PCT. PMID:2831294

High-Performance Polymer Solar Cells Based on a Wide-Bandgap Polymer Containing Pyrrolo[3,4-f]benzotriazole-5,7-dione with a Power Conversion Efficiency of 8.63.

PubMed

Lan, Liuyuan; Chen, Zhiming; Hu, Qin; Ying, Lei; Zhu, Rui; Liu, Feng; Russell, Thomas P; Huang, Fei; Cao, Yong

2016-09-01

A novel donor-acceptor type conjugated polymer based on a building block of 4,8-di(thien-2-yl) - 6-octyl-2-octyl-5 H- pyrrolo[3,4- f ]benzotriazole-5,7(6 H )-dione (TZBI) as the acceptor unit and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo-[1,2- b :4,5- b' ]dithiophene as the donor unit, named as PTZBIBDT, is developed and used as an electron-donating material in bulk-heterojunction polymer solar cells. The resulting copolymer exhibits a wide bandgap of 1.81 eV along with relatively deep highest occupied molecular orbital energy level of -5.34 eV. Based on the optimized processing conditions, including thermal annealing, and the use of a water/alcohol cathode interlayer, the single-junction polymer solar cell based on PTZBIBDT:PC 71 BM ([6,6]-phenyl-C 71 -butyric acid methyl ester) blend film affords a power conversion efficiency of 8.63% with an open-circuit voltage of 0.87 V, a short circuit current of 13.50 mA cm -2 , and a fill factor of 73.95%, which is among the highest values reported for wide-bandgap polymers-based single-junction organic solar cells. The morphology studies on the PTZBIBDT:PC 71 BM blend film indicate that a fibrillar network can be formed and the extent of phase separation can be mani-pulated by thermal annealing. These results indicate that the TZBI unit is a very promising building block for the synthesis of wide-bandgap polymers for high-performance single-junction and tandem (or multijunction) organic solar cells.

Impact of Selection of Cord Blood Units from the United States and Swiss Registries on the Cost of Banking Operations

PubMed Central

Bart, Thomas; Boo, Michael; Balabanova, Snejana; Fischer, Yvonne; Nicoloso, Grazia; Foeken, Lydia; Oudshoorn, Machteld; Passweg, Jakob; Tichelli, Andre; Kindler, Vincent; Kurtzberg, Joanne; Price, Thomas; Regan, Donna; Shpall, Elizabeth J.; Schwabe, Rudolf

2013-01-01

Background Over the last 2 decades, cord blood (CB) has become an important source of blood stem cells. Clinical experience has shown that CB is a viable source for blood stem cells in the field of unrelated hematopoietic blood stem cell transplantation. Methods Studies of CB units (CBUs) stored and ordered from the US (National Marrow Donor Program (NMDP) and Swiss (Swiss Blood Stem Cells (SBSQ)) CB registries were conducted to assess whether these CBUs met the needs of transplantation patients, as evidenced by units being selected for transplantation. These data were compared to international banking and selection data (Bone Marrow Donors Worldwide (BMDW), World Marrow Donor Association (WMDA)). Further analysis was conducted on whether current CB banking practices were economically viable given the units being selected from the registries for transplant. It should be mentioned that our analysis focused on usage, deliberately omitting any information about clinical outcomes of CB transplantation. Results A disproportionate number of units with high total nucleated cell (TNC) counts are selected, compared to the distribution of units by TNC available. Therefore, the decision to use a low threshold for banking purposes cannot be supported by economic analysis and may limit the economic viability of future public CB banking. Conclusions We suggest significantly raising the TNC level used to determine a bankable unit. A level of 125 × 107 TNCs, maybe even 150 × 107 TNCs, might be a viable banking threshold. This would improve the return on inventory investments while meeting transplantation needs based on current selection criteria. PMID:23637645

A Near Zero Refractive Index Metamaterial for Electromagnetic Invisibility Cloaking Operation

PubMed Central

Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2015-01-01

The paper reveals the design of a unit cell of a metamaterial that shows more than 2 GHz wideband near zero refractive index (NZRI) property in the C-band region of microwave spectra. The two arms of the unit cell were splitted in such a way that forms a near-pi-shape structure on epoxy resin fiber (FR-4) substrate material. The reflection and transmission characteristics of the unit cell were achieved by utilizing finite integration technique based simulation software. Measured results were presented, which complied well with simulated results. The unit cell was then applied to build a single layer rectangular-shaped cloak that operates in the C-band region where a metal cylinder was perfectly hidden electromagnetically by reducing the scattering width below zero. Moreover, the unit cell shows NZRI property there. The experimental result for the cloak operation was presented in terms of S-parameters as well. In addition, the same metamaterial shell was also adopted for designing an eye-shaped and triangular-shaped cloak structure to cloak the same object, and cloaking operation is achieved in the C-band, as well with slightly better cloaking performance. The novel design, NZRI property, and single layer C-band cloaking operation has made the design a promising one in the electromagnetic paradigm. PMID:28793472

A Near Zero Refractive Index Metamaterial for Electromagnetic Invisibility Cloaking Operation.

PubMed

Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2015-07-29

The paper reveals the design of a unit cell of a metamaterial that shows more than 2 GHz wideband near zero refractive index (NZRI) property in the C-band region of microwave spectra. The two arms of the unit cell were splitted in such a way that forms a near-pi-shape structure on epoxy resin fiber (FR-4) substrate material. The reflection and transmission characteristics of the unit cell were achieved by utilizing finite integration technique based simulation software. Measured results were presented, which complied well with simulated results. The unit cell was then applied to build a single layer rectangular-shaped cloak that operates in the C-band region where a metal cylinder was perfectly hidden electromagnetically by reducing the scattering width below zero. Moreover, the unit cell shows NZRI property there. The experimental result for the cloak operation was presented in terms of S-parameters as well. In addition, the same metamaterial shell was also adopted for designing an eye-shaped and triangular-shaped cloak structure to cloak the same object, and cloaking operation is achieved in the C-band, as well with slightly better cloaking performance. The novel design, NZRI property, and single layer C-band cloaking operation has made the design a promising one in the electromagnetic paradigm.

An isolation-enhanced quad-element antenna using suspended solid wires for LTE small-cell base stations

NASA Astrophysics Data System (ADS)

Chen, Yen-Sheng; Zhou, Huang-Cheng

2017-05-01

This paper presents a multiple-input-multiple-output (MIMO) antenna that has four-unit elements enabled by an isolation technique for long-term evolution (LTE) small-cell base stations. While earlier studies on MIMO base-station antennas cope with either a lower LTE band (698-960 MHz) or an upper LTE band (1710-2690 MHz), the proposed antenna meets the full LTE specification, yet it uses the maximum number of unit elements to increase channel capacity. The antenna configuration is optimized for good impedance matching and high radiation efficiency. In particular, as the spacing between unit elements is so small that severe mutual coupling occurs, we propose a simple structure with extremely low costs to enhance the isolation. By using suspended solid wires interconnecting the position having strong coupled current of two adjacent elements, an isolation enhancement of 37 dB is achieved. Although solid wires inherently aim at direct-current applications, this work successfully employs such a low-cost technique to microwave antenna development. Experimental results have validated the design guidelines and the proposed configuration, showing that antenna performances including impedance matching, isolation, radiation features, signal correlation, and channel capacity gain are highly desired for LTE small-cell base stations.

Sensitivity of cell-based biosensors to environmental variables.

PubMed

Gilchrist, Kristin H; Giovangrandi, Laurent; Whittington, R Hollis; Kovacs, Gregory T A

2005-01-15

Electrically active living cells cultured on extracellular electrode arrays are utilized to detect biologically active agents. Because cells are highly sensitive to environmental conditions, environmental fluctuations can elicit cellular responses that contribute to the noise in a cell-based biosensor system. Therefore, the characterization and control of environmental factors such as temperature, pH, and osmolarity is critical in such a system. The cell-based biosensor platform described here utilizes the measurement of action potentials from cardiac cells cultured on electrode arrays. A recirculating fluid flow system is presented for use in dose-response experiments that regulates temperature within +/-0.2 degrees C, pH to within +/-0.05 units, and allows no significant change in osmolarity. Using this system, the relationship between the sensor output parameters and environmental variation was quantified. Under typical experimental conditions, beat rate varied approximately 10% per degree change in temperature or per 0.1 unit change in pH. Similar relationships were measured for action potential amplitude, duration, and conduction velocity. For the specific flow system used in this work, the measured environmental sensitivity resulted in an overall beat rate variation of +/-4.7% and an overall amplitude variation of +/-3.3%. The magnitude of the noise due to environmental sensitivity has a large impact on the detection capability of the cell-based system. The significant responses to temperature, pH, and osmolarity have important implications for the use of living cells in detection systems and should be considered in the design and evaluation of such systems.

Polymer electrolyte fuel cell mini power unit for portable application

NASA Astrophysics Data System (ADS)

Urbani, F.; Squadrito, G.; Barbera, O.; Giacoppo, G.; Passalacqua, E.; Zerbinati, O.

This paper describes the design, realisation and test of a power unit based on a polymer electrolyte fuel cell, operating at room temperature, for portable application. The device is composed of an home made air breathing fuel cell stack, a metal hydride tank for H 2 supply, a dc-dc converter for power output control and a fan for stack cooling. The stack is composed by 10 cells with an active surface of 25 cm 2 and produces a rated power of 15 W at 6 V and 2 A. The stack successfully runs with end-off fed hydrogen without appreciable performance degradation during the time. The final assembled system is able to generate 12 W at 9.5 V, and power a portable DVD player for 3 h in continuous. The power unit has collected about 100 h of operation without maintenance.

Primary CNS germ cell tumors in Japan and the United States: an analysis of 4 tumor registries

PubMed Central

McCarthy, Bridget J.; Shibui, Soichiro; Kayama, Takamasa; Miyaoka, Etsuo; Narita, Yoshitaka; Murakami, Michiko; Matsuda, Ayako; Matsuda, Tomohiro; Sobue, Tomotaka; Palis, Bryan E.; Dolecek, Therese A.; Kruchko, Carol; Engelhard, Herbert H.; Villano, J. Lee

2012-01-01

Intracranial germ cell tumors (GCTs) are relatively rare. Their incidence has been considered to be higher in East Asia than in the United States. This study estimates the incidence of CNS GCTs in Japan and the United States, investigates gender discrepancies in each country, and describes treatment outcomes. Data on primary CNS GCTs from 4 databases were utilized: population-based malignant incidence data from (1) the Japan Cancer Surveillance Research Group (2004–2006; 14 registries), malignant and nonmalignant incidence data from (2) the Surveillance, Epidemiology, and End Results Program (2004–2008; 17 registries), and hospital-based observed survival data from (3) the Brain Tumor Registry of Japan (1984–2000) and (4) the US National Cancer Data Base (1990–2003). Incidence rates per 100 000 for malignant GCTs were not statistically significantly different between Japan (males = 0.143, females = 0.046) and the United States (males = 0.118, females = 0.030). The malignant incidence-rate ratio was higher for pineal GCTs versus nonpineal (ie, the rest of the brain) GCTs in Japan (11.5:1 vs 1.9:1, respectively) and the United States (16.0:1 vs 1.7:1, respectively). In general, 5-year survival estimates were high: over 75% for all GCTs, and over 81% for germinomas, regardless of the type of treatment in either Japan or the United States. The incidence of primary GCTs is similar between Japan and the United States and has the same gender-based patterns by location. High rates of survival were observed in both countries. PMID:22869621

TADs are 3D structural units of higher-order chromosome organization in Drosophila

PubMed Central

Szabo, Quentin; Jost, Daniel; Chang, Jia-Ming; Cattoni, Diego I.; Papadopoulos, Giorgio L.; Bonev, Boyan; Sexton, Tom; Gurgo, Julian; Jacquier, Caroline; Nollmann, Marcelo; Bantignies, Frédéric; Cavalli, Giacomo

2018-01-01

Deciphering the rules of genome folding in the cell nucleus is essential to understand its functions. Recent chromosome conformation capture (Hi-C) studies have revealed that the genome is partitioned into topologically associating domains (TADs), which demarcate functional epigenetic domains defined by combinations of specific chromatin marks. However, whether TADs are true physical units in each cell nucleus or whether they reflect statistical frequencies of measured interactions within cell populations is unclear. Using a combination of Hi-C, three-dimensional (3D) fluorescent in situ hybridization, super-resolution microscopy, and polymer modeling, we provide an integrative view of chromatin folding in Drosophila. We observed that repressed TADs form a succession of discrete nanocompartments, interspersed by less condensed active regions. Single-cell analysis revealed a consistent TAD-based physical compartmentalization of the chromatin fiber, with some degree of heterogeneity in intra-TAD conformations and in cis and trans inter-TAD contact events. These results indicate that TADs are fundamental 3D genome units that engage in dynamic higher-order inter-TAD connections. This domain-based architecture is likely to play a major role in regulatory transactions during DNA-dependent processes. PMID:29503869

The TMI regenerable solid oxide fuel cell

NASA Technical Reports Server (NTRS)

Cable, Thomas L.

1995-01-01

Energy storage and production in space requires rugged, reliable hardware which minimizes weight, volume, and maintenance while maximizing power output and usable energy storage. These systems generally consist of photovoltaic solar arrays which operate during sunlight cycles to provide system power and regenerate fuel (hydrogen) via water electrolysis; during dark cycles, hydrogen is converted by the fuel cell into system. The currently preferred configuration uses two separate systems (fuel cell and electrolyzer) in conjunction with photovoltaic cells. Fuel cell/electrolyzer system simplicity, reliability, and power-to-weight and power-to-volume ratios could be greatly improved if both power production (fuel cell) and power storage (electrolysis) functions can be integrated into a single unit. The Technology Management, Inc. (TMI), solid oxide fuel cell-based system offers the opportunity to both integrate fuel cell and electrolyzer functions into one unit and potentially simplify system requirements. Based an the TMI solid oxide fuel cell (SOPC) technology, the TMI integrated fuel cell/electrolyzer utilizes innovative gas storage and operational concepts and operates like a rechargeable 'hydrogen-oxygen battery'. Preliminary research has been completed on improved H2/H2O electrode (SOFC anode/electrolyzer cathode) materials for solid oxide, regenerative fuel cells. Improved H2/H2O electrode materials showed improved cell performance in both fuel cell and electrolysis modes in reversible cell tests. ln reversible fuel cell/electrolyzer mode, regenerative fuel cell efficiencies (ratio of power out (fuel cell mode) to power in (electrolyzer model)) improved from 50 percent (using conventional electrode materials) to over 80 percent. The new materials will allow the TMI SOFC system to operate as both the electrolyzer and fuel cell in a single unit. Preliminary system designs have also been developed which indicate the technical feasibility of using the TMI SOFC technology for space applications with high energy storage efficiencies and high specific energy. Development of small space systems would also have potential dual-use, terrestrial applications.

The TMI regenerable solid oxide fuel cell

NASA Astrophysics Data System (ADS)

Cable, Thomas L.

1995-04-01

Energy storage and production in space requires rugged, reliable hardware which minimizes weight, volume, and maintenance while maximizing power output and usable energy storage. These systems generally consist of photovoltaic solar arrays which operate during sunlight cycles to provide system power and regenerate fuel (hydrogen) via water electrolysis; during dark cycles, hydrogen is converted by the fuel cell into system. The currently preferred configuration uses two separate systems (fuel cell and electrolyzer) in conjunction with photovoltaic cells. Fuel cell/electrolyzer system simplicity, reliability, and power-to-weight and power-to-volume ratios could be greatly improved if both power production (fuel cell) and power storage (electrolysis) functions can be integrated into a single unit. The Technology Management, Inc. (TMI), solid oxide fuel cell-based system offers the opportunity to both integrate fuel cell and electrolyzer functions into one unit and potentially simplify system requirements. Based an the TMI solid oxide fuel cell (SOPC) technology, the TMI integrated fuel cell/electrolyzer utilizes innovative gas storage and operational concepts and operates like a rechargeable 'hydrogen-oxygen battery'. Preliminary research has been completed on improved H2/H2O electrode (SOFC anode/electrolyzer cathode) materials for solid oxide, regenerative fuel cells. Improved H2/H2O electrode materials showed improved cell performance in both fuel cell and electrolysis modes in reversible cell tests. ln reversible fuel cell/electrolyzer mode, regenerative fuel cell efficiencies (ratio of power out (fuel cell mode) to power in (electrolyzer model)) improved from 50 percent (using conventional electrode materials) to over 80 percent. The new materials will allow the TMI SOFC system to operate as both the electrolyzer and fuel cell in a single unit. Preliminary system designs have also been developed which indicate the technical feasibility of using the TMI SOFC technology for space applications with high energy storage efficiencies and high specific energy. Development of small space systems would also have potential dual-use, terrestrial applications.

Simulation of Zr content in TiZrCuNi brazing filler metal for Ti6Al4V alloy

NASA Astrophysics Data System (ADS)

Yue, Xishan; Xie, Zonghong; Jing, Yongjuan

2017-07-01

To optimize the Zr content in Ti-based filler metal, the covalent electron on the nearest atoms bond in unit cell ( n A u-v ) with Ti-based BCC structure was calculated, in which the brazing temperature was considered due to its influence on the lattice parameter. Based on EET theory (The Empirical Electron Theory for solid and molecules), n_{{A}}^{{u - v}} represents the strength of the unit cell with defined element composition and structure, which reflects the effect from solid solution strengthening on the strength of the unit cell. For Ti-Zr-15Cu-10Ni wt% filler metal, it kept constant as 0.3476 with Zr as 37.5˜45 wt% and decreased to 0.333 with Zr decreasing from 37.5 to 25 wt%. Finally, it increased up to 0.3406 with Zr as 2˜10 wt%. Thus, Ti-based filler metal with Zr content being 2˜10 wt% is suggested based on the simulation results. Moreover, the calculated covalent electron of n A u-v showed good agreement with the hardness of the joint by filler 37.5Zr and 10Zr. The composition of Ti-10Zr-15Cu-10Ni wt% was verified in this study with higher tensile strength of the brazing joint and uniform microstructure of the interface.

The Design and Analysis of a Novel Split-H-Shaped Metamaterial for Multi-Band Microwave Applications

PubMed Central

Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2014-01-01

This paper presents the design and analysis of a novel split-H-shaped metamaterial unit cell structure that is applicable in a multi-band frequency range and that exhibits negative permeability and permittivity in those frequency bands. In the basic design, the separate split-square resonators are joined by a metal link to form an H-shaped unit structure. Moreover, an analysis and a comparison of the 1 × 1 array and 2 × 2 array structures and the 1 × 1 and 2 × 2 unit cell configurations were performed. All of these configurations demonstrate multi-band operating frequencies (S-band, C-band, X-band and Ku-band) with double-negative characteristics. The equivalent circuit model and measured result for each unit cell are presented to validate the resonant behavior. The commercially available finite-difference time-domain (FDTD)-based simulation software, Computer Simulation Technology (CST) Microwave Studio, was used to obtain the reflection and transmission parameters of each unit cell. This is a novel and promising design in the electromagnetic paradigm for its simplicity, scalability, double-negative characteristics and multi-band operation. PMID:28788116

The Design and Analysis of a Novel Split-H-Shaped Metamaterial for Multi-Band Microwave Applications.

PubMed

Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2014-07-02

This paper presents the design and analysis of a novel split-H-shaped metamaterial unit cell structure that is applicable in a multi-band frequency range and that exhibits negative permeability and permittivity in those frequency bands. In the basic design, the separate split-square resonators are joined by a metal link to form an H-shaped unit structure. Moreover, an analysis and a comparison of the 1 × 1 array and 2 × 2 array structures and the 1 × 1 and 2 × 2 unit cell configurations were performed. All of these configurations demonstrate multi-band operating frequencies (S-band, C-band, X-band and K u -band) with double-negative characteristics. The equivalent circuit model and measured result for each unit cell are presented to validate the resonant behavior. The commercially available finite-difference time-domain (FDTD)-based simulation software, Computer Simulation Technology (CST) Microwave Studio, was used to obtain the reflection and transmission parameters of each unit cell. This is a novel and promising design in the electromagnetic paradigm for its simplicity, scalability, double-negative characteristics and multi-band operation.

Cadmium Telluride Solar Cells | Photovoltaic Research | NREL

Science.gov Websites

Cadmium Telluride Solar Cells Cadmium Telluride Solar Cells Photovoltaic (PV) solar cells based on leadership. The United States is the leader in CdTe PV manufacturing, and NREL has been at the forefront of research and development (R&D) in this area. PV Research Other Materials & Devices pages: High

Cord blood serum-based eye drops: the impact of donor haematological and obstetric factors on the variability of epidermal growth factor levels

PubMed Central

Versura, Piera; Buzzi, Marina; Giannaccare, Giuseppe; Grillini, Marco; Terzi, Adriana; Pagliaro, Pasqualepaolo; Campos, Emilio C.

2014-01-01

Background Cord blood serum (CBS)-based eye drops are successfully used in corneal epithelial wound healing and are prepared to supply a known amount of epidermal growth factor (EGF). Product standardisation includes expensive EGF dosage in all cord blood (CB) units. The influence of donor obstetric and haematological characteristics on EGF content was evaluated, to exclude unsuitable CBS and pre-select those CB units able to provide the correct EGF supply for healing corneal wounds. Materials and methods Data were retrospectively collected from 135 donors included in the Emilia Romagna Cord Blood Bank records. Obstetric characteristics, parity and gestational age of the mother, sex, birth weight and Apgar score of the neonate, placental weight, duration of labour and mode of delivery were considered. Haematological characteristics, CD34+ cell number, and total nucleated cell, white blood cell and platelet counts were recorded. EGF content in CB units was estimated by enzyme-linked immunosorbent assay. Statistical evaluation was performed by Mann-Whitney unpaired and Student’s t tests. Correlations between variables were evaluated by using Pearson’s (r) or Spearman’s (ρ) correlation coefficients. Results EGF content was significantly higher in CBS from donors aged <30 years and after vaginal deliveries as compared with scheduled Caesarean sections (1,386±580 vs 1,106±391 pg/mL; P=0.002). EGF content was significantly correlated with duration of labour (r=0.45; P=0.0001), number of CD34+ cells/mL (r=0.3; P=0.002) particularly in vaginal deliveries (r=0.36; P=0.003), mother’s age (−0.25; P=0.005), neonate’s birth weight (r=0.27; P=0.005), and total nucleated cell (r=0.25; P=0.006), white cell (r=0.29; P=0.001) and platelet (r=0.24; P=0.009) counts. No significant correlations were found between EGF content and parity, gestational age, placental weight, neonate’s sex or Apgar scores. Discussion EGF levels are higher in CB units from younger mothers (<30 years), with longer labour duration (>6 hours), and higher CD34+ cell content (>0.05×106/mL). In order to optimise the preparation and costs of CBS–based eye drops, pre-selection of CB units is recommended. PMID:24120597

Design, Synthesis, and Biological Evaluations of Asymmetric Bow-Tie PAMAM Dendrimer-Based Conjugates for Tumor-Targeted Drug Delivery.

PubMed

Wang, Tao; Zhang, Yaozhong; Wei, Longfei; Teng, Yuhan G; Honda, Tadashi; Ojima, Iwao

2018-04-30

A unique asymmetric bow-tie poly(amidoamine) (PAMAM) dendrimer (ABTD) scaffold was designed and developed as a well-defined macromolecular carrier for tumor-targeted drug delivery. The ABTD scaffold in this study consists of a G3-half-dendron (G3-HD) unit and a G1-half-dendron (G1-HD) unit, bearing thiol moiety in each unit and a bis(maleimide) linker unit, which undergo sequential thiol-maleimide coupling to assemble the scaffold. This assembly methodology is applicable to all other combinations of different generations of PAMAM dendrimers. In the prototype ABTD in this study, 16 biotin moieties were tethered to the G3-HD unit and 4 payloads (new-generation taxoid) to the G1-HD via a self-immolative linker to form an ABTD-tumor-targeting conjugate (ABTD-TTC-1). Two other ABTD-TTCs were synthesized, wherein the G1-HD unit was tethered to a fluorescence-labeled taxoid or to a fluorescent probe. These three ABTD-TTCs were constructed by using a common key ABTD 6 bearing a terminal acetylene group in the G1-HD unit, which was fully characterized as a single molecule by high-resolution mass spectrometry and NMR despite its high molecular weight ( M w : 12 876). Then, the click reaction was employed to couple ABTD 6 with a small-molecule payload or fluorescence probe unit bearing a terminal azide moiety. ABTD-TTC-3, as a surrogate of ABTD-TTC-2, showed substantially enhanced internalization into two cancer cell lines via receptor-mediated endocytosis, attributed to multibinding effect. ABTD-TTC-1 exhibited a remarkable selectivity to cancer cells (1400-7500 times) compared to human normal cells, which demonstrates the salient feature and bright prospect of the ABTD-based tumor-targeted drug-delivery system.

Research of the impact of coupling between unit cells on performance of linear-to-circular polarization conversion metamaterial with half transmission and half reflection

NASA Astrophysics Data System (ADS)

Guo, Mengchao; Zhou, Kan; Wang, Xiaokun; Zhuang, Haiyan; Tang, Dongming; Zhang, Baoshan; Yang, Yi

2018-04-01

In this paper, the impact of coupling between unit cells on the performance of linear-to-circular polarization conversion metamaterial with half transmission and half reflection is analyzed by changing the distance between the unit cells. An equivalent electrical circuit model is then built to explain it based on the analysis. The simulated results show that, when the distance between the unit cells is 23 mm, this metamaterial converts half of the incident linearly-polarized wave into reflected left-hand circularly-polarized wave and converts the other half of it into transmitted left-hand circularly-polarized wave at 4.4 GHz; when the distance is 28 mm, this metamaterial reflects all of the incident linearly-polarized wave at 4.4 GHz; and when the distance is 32 mm, this metamaterial converts half of the incident linearly-polarized wave into reflected right-hand circularly-polarized wave and converts the other half of it into transmitted right-hand circularly-polarized wave at 4.4 GHz. The tunability is realized successfully. The analysis shows that the changes of coupling between unit cells lead to the changes of performance of this metamaterial. The coupling between the unit cells is then considered when building the equivalent electrical circuit model. The built equivalent electrical circuit model can be used to perfectly explain the simulated results, which confirms the validity of it. It can also give help to the design of tunable polarization conversion metamaterials.

Geometric modeling of space-optimal unit-cell-based tissue engineering scaffolds

NASA Astrophysics Data System (ADS)

Rajagopalan, Srinivasan; Lu, Lichun; Yaszemski, Michael J.; Robb, Richard A.

2005-04-01

Tissue engineering involves regenerating damaged or malfunctioning organs using cells, biomolecules, and synthetic or natural scaffolds. Based on their intended roles, scaffolds can be injected as space-fillers or be preformed and implanted to provide mechanical support. Preformed scaffolds are biomimetic "trellis-like" structures which, on implantation and integration, act as tissue/organ surrogates. Customized, computer controlled, and reproducible preformed scaffolds can be fabricated using Computer Aided Design (CAD) techniques and rapid prototyping devices. A curved, monolithic construct with minimal surface area constitutes an efficient substrate geometry that promotes cell attachment, migration and proliferation. However, current CAD approaches do not provide such a biomorphic construct. We address this critical issue by presenting one of the very first physical realizations of minimal surfaces towards the construction of efficient unit-cell based tissue engineering scaffolds. Mask programmability, and optimal packing density of triply periodic minimal surfaces are used to construct the optimal pore geometry. Budgeted polygonization, and progressive minimal surface refinement facilitate the machinability of these surfaces. The efficient stress distributions, as deduced from the Finite Element simulations, favor the use of these scaffolds for orthopedic applications.

Global Distribution of Businesses Marketing Stem Cell-Based Interventions.

PubMed

Berger, Israel; Ahmad, Amina; Bansal, Akhil; Kapoor, Tanvir; Sipp, Douglas; Rasko, John E J

2016-08-04

A structured search reveals that online marketing of stem-cell-based interventions is skewed toward developed economies including the United States, Ireland, Australia, and Germany. Websites made broad, imprecise therapeutic claims and frequently failed to detail procedures. Widespread marketing poses challenges to regulators, bioethicists, and those seeking realistic hope from therapies. Copyright © 2016 Elsevier Inc. All rights reserved.

Microbial fuel cells as pollutant treatment units: Research updates.

PubMed

Zhang, Quanguo; Hu, Jianjun; Lee, Duu-Jong

2016-10-01

Microbial fuel cells (MFC) are a device that can convert chemical energy in influent substances to electricity via biological pathways. Based on the consent that MFC technology should be applied as a waste/wastewater treatment unit rather than a renewable energy source, this mini-review discussed recent R&D efforts on MFC technologies for pollutant treatments and highlighted the challenges and research and development needs. Owing to the low power density levels achievable by larger-scale MFC, the MFC should be used as a device other than energy source such as being a pollutant treatment unit. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of the Appropriateness of the Use of Peltier Cells as Energy Sources.

PubMed

Hájovský, Radovan; Pieš, Martin; Richtár, Lukáš

2016-05-25

The article describes the possibilities of using Peltier cells as an energy source to power the telemetry units, which are used in large-scale monitoring systems as central units, ensuring the collection of data from sensors, processing, and sending to the database server. The article describes the various experiments that were carried out, their progress and results. Based on experiments evaluated, the paper also discusses the possibilities of using various types depending on the temperature difference of the cold and hot sides.

Analysis and optimization of solid oxide fuel cell-based auxiliary power units using a generic zero-dimensional fuel cell model

NASA Astrophysics Data System (ADS)

Göll, S.; Samsun, R. C.; Peters, R.

Fuel-cell-based auxiliary power units can help to reduce fuel consumption and emissions in transportation. For this application, the combination of solid oxide fuel cells (SOFCs) with upstream fuel processing by autothermal reforming (ATR) is seen as a highly favorable configuration. Notwithstanding the necessity to improve each single component, an optimized architecture of the fuel cell system as a whole must be achieved. To enable model-based analyses, a system-level approach is proposed in which the fuel cell system is modeled as a multi-stage thermo-chemical process using the "flowsheeting" environment PRO/II™. Therein, the SOFC stack and the ATR are characterized entirely by corresponding thermodynamic processes together with global performance parameters. The developed model is then used to achieve an optimal system layout by comparing different system architectures. A system with anode and cathode off-gas recycling was identified to have the highest electric system efficiency. Taking this system as a basis, the potential for further performance enhancement was evaluated by varying four parameters characterizing different system components. Using methods from the design and analysis of experiments, the effects of these parameters and of their interactions were quantified, leading to an overall optimized system with encouraging performance data.

Spin-1/2 kagome XXZ model in a field: Competition between lattice nematic and solid orders

NASA Astrophysics Data System (ADS)

Kshetrimayum, Augustine; Picot, Thibaut; Orús, Román; Poilblanc, Didier

2016-12-01

We study numerically the spin-1/2 XXZ model in a field on an infinite kagome lattice. We use different algorithms based on infinite projected entangled pair states (iPEPSs) for this, namely, (i) an approach with simplex tensors and a 9-site unit cell, and (ii) an approach based on coarse-graining three spins in the kagome lattice and mapping it to a square-lattice model with local and nearest-neighbor interactions, with the usual PEPS tensors, 6- and 12-site unit cells. Similarly to our previous calculation at the SU(2)-symmetric point (Heisenberg Hamiltonian), for any anisotropy from the Ising limit to the XY limit, we also observe the emergence of magnetization plateaus as a function of the magnetic field, at mz=1/3 using 6-, 9-, and 12-site PEPS unit cells, and at mz=1/9 ,5/9 , and 7/9 using a 9-site PEPS unit cell, the latter setup being able to accommodate √{3 }×√{3 } solid order. We also find that, at mz=1/3 , (lattice) nematic and √{3 }×√{3 } VBC-order states are degenerate within the accuracy of the nine-site simplex method, for all anisotropy. The 6- and 12-site coarse-grained PEPS methods produce almost-degenerate nematic and 1 ×2 VBC-solid orders. We also find that, within our accuracy, the six-site coarse-grained PEPS method gives slightly lower energies, which can be explained by the larger amount of entanglement this approach can handle, even in cases where the PEPS unit cell is not commensurate with the expected ground-state unit cell. Furthermore, we do not observe chiral spin liquid behaviors at and close to the XY point, as has been recently proposed. Our results are the first tensor network investigations of the XXZ model in a field and reveal the subtle competition between nearby magnetic orders in numerical simulations of frustrated quantum antiferromagnets, as well as the delicate interplay between energy optimization and symmetry in tensor network numerical simulations.

A self-assembling luminescent lanthanide molecular nanoparticle with potential for live cell imaging.

PubMed

Yang, Xiaoping; Wang, Shiqing; Zhang, Yali; Liang, Guang; Zhu, Ting; Zhang, Lijie; Huang, Shaoming; Schipper, Desmond; Jones, Richard A

2018-05-28

Four luminescent 32-metal Cd-Tb nanoclusters, [Tb 8 Cd 24 (L 1 ) 12 (OAc) 48 ] ( 1 ), [Tb 8 Cd 24 (L 2 ) 12 (OAc) 48 ] ( 2 ), [Tb 8 Cd 24 (L 3 ) 12 (OAc) 48 ] ( 3 ) and [Tb 8 Cd 24 (L 2 ) 12 (1,4-BDC) 4 (OAc) 38 (OH) 2 ] ( 4 ), were constructed from three specially designed chain-like Schiff base ligands H 2 L 1-3 with flexible carbon-carbon backbones containing 5, 6 and 10 methylene units, respectively. The clusters exhibit drum-like structures and can be imaged using transmission electron microscopy (TEM). In addition to the Schiff base ligands (the primary energy transfer donors), four 1,4-BDC bridging units were successfully introduced into the structure of 4 . In addition to providing increased structural stability, the 1,4-BDC units act as secondary energy transfer donors providing extra energy for lanthanide luminescence, which results in improved luminescence properties when compared to those of the related Cd-Ln nanoclusters without 1,4-BDC units. In vitro investigations on 4 with SGC and PANC cancer cells revealed an accumulation of the molecular nanoparticles in the cells, as confirmed by confocal microscopy. The cytotoxicity of 4 toward the SGC and PANC cells is moderate (IC 50 values of 4 lie in the range of 15-60 μM). ICP-MS analysis reveals that cellular uptakes of 4 in 1000 SGC and PANC cells after treatment for 3 hours are 0.0094 pmol and 0.015 pmol, respectively.

Tin and germanium based two-dimensional Ruddlesden-Popper hybrid perovskites for potential lead-free photovoltaic and photoelectronic applications.

PubMed

Ma, Liang; Ju, Ming-Gang; Dai, Jun; Zeng, Xiao Cheng

2018-06-21

Despite their high power conversion efficiency, the commercial applications of hybrid organic-inorganic lead (Pb) halide perovskite based solar cells are still hampered by concerns about the toxicity of Pb and the structural stability in open air. Herein, based on density-functional theory computation, we show that lead-free tin (Sn) and germanium (Ge) based two-dimensional (2D) Ruddlesden-Popper hybrid organic-inorganic perovskites with a thickness of a few unit-cells, BA2MAn-1MnI3n+1 (M = Sn or Ge, n = 2-4), possess desirable electronic, excitonic and light absorption properties, thereby showing promise for photovoltaic and/or photoelectronic applications. In particular, we show that by increasing the layer thickness of the Sn-based 2D perovskites, the bandgap can be lowered towards the optimal range (0.9-1.6 eV) for solar cells. Meanwhile, the exciton binding energy is reduced to a more optimal value. In addition, theoretical assessment indicates that the thermodynamic stability of Sn-/Ge-based 2D perovskites is notably enhanced compared to that of their 3D analogues. These features render the Sn-/Ge-based 2D hybrid perovskites with a thickness of a few tens of unit cells promising lead-free perovskites with much improved structural stabilities for photovoltaic and/or photoelectronic applications.

Regulatory requirements in the good manufacturing practice production of an epithelial cell graft for ocular surface reconstruction.

PubMed

Sheth-Shah, Radhika; Vernon, Amanda J; Seetharaman, Shankar; Neale, Michael H; Daniels, Julie T

2016-04-01

In the past decade, stem cell therapy has been increasingly employed for the treatment of various diseases. Subsequently, there has been a great interest in the manufacture of stem cells under good manufacturing practice, which is required by law for their use in humans. The cells for sight Stem Cell Therapy Research Unit, based at UCL Institute of Ophthalmology, delivers somatic cell-based and tissue-engineered therapies to patients suffering from blinding eye diseases at Moorfields Eye Hospital (London, UK). The following article is based on our experience in the conception, design, construction, validation and manufacturing within a good manufacturing practice manufacturing facility based in the UK. As such the regulations can be extrapolated to the 28 members stated within the EU. However, the principles may have a broad relevance outside the EU.

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

PubMed

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.

New paradigms in internal architecture design and freeform fabrication of tissue engineering porous scaffolds.

PubMed

Yoo, Dongjin

2012-07-01

Advanced additive manufacture (AM) techniques are now being developed to fabricate scaffolds with controlled internal pore architectures in the field of tissue engineering. In general, these techniques use a hybrid method which combines computer-aided design (CAD) with computer-aided manufacturing (CAM) tools to design and fabricate complicated three-dimensional (3D) scaffold models. The mathematical descriptions of micro-architectures along with the macro-structures of the 3D scaffold models are limited by current CAD technologies as well as by the difficulty of transferring the designed digital models to standard formats for fabrication. To overcome these difficulties, we have developed an efficient internal pore architecture design system based on triply periodic minimal surface (TPMS) unit cell libraries and associated computational methods to assemble TPMS unit cells into an entire scaffold model. In addition, we have developed a process planning technique based on TPMS internal architecture pattern of unit cells to generate tool paths for freeform fabrication of tissue engineering porous scaffolds. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

Performance analysis of a potassium-base AMTEC cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

1998-07-01

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 surfacemore » 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.« less

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: UTC FUEL CELLS' PC25C POWER PLANT - GAS PROCESSING UNIT PERFORMANCE FOR ANAEROBIC DIGESTER GAS

EPA Science Inventory

Under EPA’s Environmental Technology Verification program, which provides objective and scientific third party analysis of new technology that can benefit the environment, a combined heat and power system based on the UTC Fuel Cell's PC25C Fuel Cell Power Plant was evaluated. The...

2D-3D switchable display based on a passive polymeric lenticular lens array and electrically suppressed ferroelectric liquid crystal.

PubMed

Shi, Liangyu; Srivastava, Abhishek Kumar; Wai Tam, Alwin Ming; Chigrinov, Vladimir Grigorievich; Kwok, Hoi Sing

2017-09-01

We reveal a 2D-3D switchable lens unit that is based on a polarization-sensitive microlens array and a polarization selector unit made of an electrically suppressed helix ferroelectric liquid crystal (ESHFLC) cell. The ESHFLCs offer a high contrast ratio (∼10k∶1) between the crossed polarizers at a low applied electric field (∼1.7  V/μm) with a small switching time (<50  μs). A special driving scheme, to switch between a 2D and 3D mode, has been developed to avoid unwanted issues related to DC accumulation in the ferroelectric liquid crystal without affecting its optical quality. The proposed lens unit is characterized by low power consumption, ultrafast response, and 3D crosstalk <5%, and can therefore find application in TVs, cell phones, etc.

Metalenses based on the non-parallel double-slit arrays

NASA Astrophysics Data System (ADS)

Shao, Hongyan; Chen, Chen; Wang, Jicheng; Pan, Liang; Sang, Tian

2017-09-01

Metalenses based on surface plasmon polaritons have played an indispensable role in ultra-thin devices designing. The amplitude, phase and polarization of electromagnetic waves all can be controlled easily by modifying the metasurface structures. Here we propose and investigate a new type of structure with Babinet-inverted nano-antennas which can provide a series of unit-cells with phase-shifts covering 2π and ensure almost same transmittance simultaneously. As a result, the wavefront can be manipulated by arraying the units in course. Metalenses with the linear asymmetrical double slit unit-cell arrays are designed and the simulative results exhibit their perfect focusing characteristics, including single-focus lenses and multi-focus lenses. The small focus size and high numerical aperture make them stand out from the traditional counterparts in application of precision sensing devices. We expect our designs will provide new insights in the practical applications for metasurfaces in data storages, optical information processing and optical holography.

Reporting unit size and measurement uncertainty: current Australian practice in clinical chemistry and haematology.

PubMed

Hawkins, Robert C; Badrick, Tony

2015-08-01

In this study we aimed to compare the reporting unit size used by Australian laboratories for routine chemistry and haematology tests to the unit size used by learned authorities and in standard laboratory textbooks and to the justified unit size based on measurement uncertainty (MU) estimates from quality assurance program data. MU was determined from Royal College of Pathologists of Australasia (RCPA) - Australasian Association of Clinical Biochemists (AACB) and RCPA Haematology Quality Assurance Program survey reports. The reporting unit size implicitly suggested in authoritative textbooks, the RCPA Manual, and the General Serum Chemistry program itself was noted. We also used published data on Australian laboratory practices.The best performing laboratories could justify their chemistry unit size for 55% of analytes while comparable figures for the 50% and 90% laboratories were 14% and 8%, respectively. Reporting unit size was justifiable for all laboratories for red cell count, >50% for haemoglobin but only the top 10% for haematocrit. Few, if any, could justify their mean cell volume (MCV) and mean cell haemoglobin concentration (MCHC) reporting unit sizes.The reporting unit size used by many laboratories is not justified by present analytical performance. Using MU estimates to determine the reporting interval for quantitative laboratory results ensures reporting practices match local analytical performance and recognises the inherent error of the measurement process.

Achieving high performance polymer tandem solar cells via novel materials design

NASA Astrophysics Data System (ADS)

Dou, Letian

Organic photovoltaic (OPV) devices show great promise in low-cost, flexible, lightweight, and large-area energy-generation applications. Nonetheless, most of the materials designed today always suffer from the inherent disadvantage of not having a broad absorption range, and relatively low mobility, which limit the utilization of the full solar spectrum. Tandem solar cells provide an effective way to harvest a broader spectrum of solar radiation by combining two or more solar cells with different absorption bands. However, for polymer solar cells, the performance of tandem devices lags behind single-layer solar cells mainly due to the lack of suitable low-bandgap polymers (near-IR absorbing polymers). In this dissertation, in order to achieve high performance, we focus on design and synthesis of novel low bandgap polymers specifically for tandem solar cells. In Chapter 3, I demonstrate highly efficient single junction and tandem polymer solar cells featuring a spectrally matched low-bandgap conjugated polymer (PBDTT-DPP: bandgap, ˜1.44 eV). The polymer has a backbone based on alternating benzodithiophene and diketopyrrolopyrrole units. A single-layer device based on the polymer provides a power conversion efficiency of ˜6%. When the polymer is applied to tandem solar cells, a power conversion efficiency of 8.62% is achieved, which was the highest certified efficiency for a polymer solar cell. To further improve this material system, in Chapter 4, I show that the reduction of the bandgap and the enhancement of the charge transport properties of the low bandgap polymer PBDTT-DPP can be accomplished simultaneously by substituting the sulfur atoms on the DPP unit with selenium atoms. The newly designed polymer PBDTT-SeDPP (Eg = 1.38 eV) shows excellent photovoltaic performance in single junction devices with PCEs over 7% and photo-response up to 900 nm. Tandem polymer solar cells based on PBDTT-SeDPP are also demonstrated with a 9.5% PCE, which are more than 10% enhancement over those based on PBDTT-DPP. Finally, in Chapter 5, I demonstrate a new polymer system based on alternating dithienopyran and benzothiadiazole units with a bandgap of 1.38 eV, high mobility, deep highest occupied molecular orbital. As a result, a single-junction device shows high external quantum efficiency of >60% and spectral response that extends to 900 nm, with a power conversion efficiency of 7.9%. The polymer enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions, which is the first certified polymer solar cell efficiency over 10%.

Manipulation of acoustic wavefront by gradient metasurface based on Helmholtz Resonators.

PubMed

Lan, Jun; Li, Yifeng; Xu, Yue; Liu, Xiaozhou

2017-09-06

We designed a gradient acoustic metasurface to manipulate acoustic wavefront freely. The broad bandwidth and high efficiency transmission are achieved by the acoustic metasurface which is constructed with a series of unit cells to provide desired discrete acoustic velocity distribution. Each unit cell is composed of a decorated metal plate with four periodically arrayed Helmholtz resonators (HRs) and a single slit. The design employs a gradient velocity to redirect refracted wave and the impedance matching between the metasurface and the background medium can be realized by adjusting the slit width of unit cell. The theoretical and numerical results show that some excellent wavefront manipulations are demonstrated by anomalous refraction, non-diffracting Bessel beam, sub-wavelength flat focusing, and effective tunable acoustic negative refraction. Our designed structure may offer potential applications for the imaging system, beam steering and acoustic lens.

Selling Stem Cells in the USA: Assessing the Direct-to-Consumer Industry.

PubMed

Turner, Leigh; Knoepfler, Paul

2016-08-04

Direct-to-consumer marketing of unapproved stem cell interventions is a well-known phenomenon in countries with lax medical regulations. However, an examination of Internet-based marketing claims revealed widespread promotion of such interventions by businesses based in the United States. Such commercial activity suggests that regulatory agencies must better oversee this marketplace. Copyright © 2016 Elsevier Inc. All rights reserved.

Full-wave simulation of a three-dimensional metamaterial prism

DOE PAGES

Basilio, Lorena I.; Langston, William L.; Warne, Larry K.; ...

2015-01-23

In our article, a negative-index metamaterial prism based on a composite unit cell containing a split-ring resonator and a z-dipole is designed and simulated. The design approach combines simulations of a single unit cell to identify the appropriate cell design (yielding the desired negative-index behavior) together with subcell modeling (which simplifies the mesh representation of the resonator geometry and allows for a larger number of resonator cells to be handled). Furthermore, to describe the methodology used in designing a n = -1 refractive index prism, our results include the effective-medium parameters, the far-field scattered patterns, and the near-zone field distributionsmore » corresponding to a normally incident plane-wave excitation of the prism.« less

Magnetic ground state and electronic structure of CeRu(2)Al(10).

PubMed

Goraus, Jerzy; Ślebarski, Andrzej

2012-03-07

We present a combined theoretical and experimental study of the electronic structure for CeRu(2)Al(10) based on ab initio band structure calculations and x-ray photoemission spectroscopy (XPS) data. Our calculations were performed for the base unit cell and for the hypothetical unit cell which enables antiferromagnetic ordering. The stability of the magnetic phase was investigated within fixed spin moment calculations. When additional 4f correlations are not included in the LSDA C U approach, CeRu(2)Al(10) exhibits an unstable magnetic configuration with the difference in total energy per unit cell between the weakly magnetic state and the non-magnetic one of the order ~0.3 meV. We found that Coulomb correlations among 4f electrons, when they are included in the LSDA C U approach, stabilize the magnetic structure. In the weakly correlated system (small U) an antiferromagnetic (AFM) ground state with the lowest total energy is preferred. The situation is, however, the opposite when the 4f correlations are strong. In this case the ferromagnetic (FM) ground state is preferred. By comparing our calculations with the experimental data we conclude that the 4f correlations in CeRu(2)Al(10) are weak. We also carried out a structural relaxation of atomic positions within the Cmcm unit cell and we found that the Al atoms exhibit noticeable displacement from their positions known from x-ray diffraction (XRD) analysis.

Consistency of the initial cell acquisition procedure is critical to the standardization of CD34+ cell enumeration by flow cytometry: results of a pairwise analysis of umbilical cord blood units and cryopreserved aliquots.

PubMed

Flores, Ana I; McKenna, David H; Montalbán, M Angeles; De la Cruz, Javier; Wagner, John E; Bornstein, Rafael

2009-04-01

The CD34+ cell content is a predictive factor for engraftment and survival after umbilical cord blood (UCB) transplantation. The high variability in the CD34 assay results in different recommended cell doses for infusion across transplant centers and also limits the clinical utility of the CD34+ cell counts provided by cord blood banks (CBBs). This bi-institutional study was intended to understand the sources of this variability. The level of CD34 agreement between the University of Minnesota (UM) and the Madrid CBB (MCBB) was evaluated on 50 UCB units before and after cryopreservation. Two cryopreserved vials per unit were thawed and processed at both laboratories. Dual-platform ISHAGE-based flow cytometry was used for CD34 enumeration. Postthaw nucleated cell recoveries were similar. However, whereas CD34+ cell enumeration before freezing was 0.35 +/- 0.22 percent, the results after thawing were 0.98 +/- 0.65 and 0.57 +/- 0.39 percent at UM and MCBB, respectively. Bland-Altman plots analysis ruled out the interchangeability of MCBB and UM CD34 values. Differences in the initial cell acquisition settings accounted for most of the CD34 discrepancy, which was no longer present after normalization of the forward scatter threshold for cell acquisition. The standardization of CD34+ cell enumeration by flow cytometry is strongly reliant on a consistent initial cell acquisition procedure. The interlaboratory variation can be minimized by using frozen cell aliquots as reference samples. Both requisites should be considered for CD34 testing and UCB unit selection by regulatory institutions involved with cord blood banking and transplantation.

Competition between magnetism and superconductivity in Eu-based intermetallic compounds

NASA Astrophysics Data System (ADS)

Stavinoha, Macy; Green, Lance; Chan, Julia; Morosan, Emilia

Eu-based intermetallic compounds present a path to discover new correlated electronic behavior in quantum materials. Reports of superconductivity, intermediate valence behavior, and heavy fermions indicate that Eu-based compounds are promising routes to study the relationship between crystallography and electronic properties. The present work is focused on EuGa4, an antiferromagnet with TN = 16 K isostructural with the tetragonal RT2M2 (R = rare earth, T = transition metal, M = metal or metalloid) family that exhibits heavy fermion behavior and unconventional superconductivity. Single crystals of the doped series (Eu1-xLax)Ga4, (Eu1-xCax)Ga4, and Eu(Ga1-xAlx)4 have been grown using the self-flux method and tested for change in unit cell volume and magnetic susceptibility. Results show that doping with Ca (isoelectronic doping) and La (hole doping) reduce TN to 12.4 K and 2.3 K, respectively, for Ca doping up to x = 0.11 and La doping up to x = 0.74 without an associated change in unit cell volume. The series Eu(Ga1-xAlx)4 has shown incommensurate-to-commensurate magnetic transitions. Future studies will aim to further decrease TN and the unit cell volume using physical pressure and chemical pressure through doping. ICAM, Gordon and Betty Moore Foundation.

Parsing Stem Cell Lineage Development Using High Content Image Analysis of Epigenetic Spatial Markers.

PubMed

Kim, Joseph J; Moghe, Prabhas V

2018-06-14

This unit describes a protocol for acquiring and analyzing high-content super-resolution images of human stem cell nuclei for the characterization and classification of the cell differentiation paths based on distinct patterns of epigenetic mark organization. Here, we describe the cell culture, immunocytochemical labeling, super-resolution imaging parameters, and MATLAB-based quantitative image analysis approaches for monitoring human mesenchymal stem cells (hMSCs) and human induced pluripotent stem cells (hiPSCs) as the cells differentiate towards various lineages. Although this protocol uses specific cell types as examples, this approach could be easily extended to a variety of cell types and nuclear epigenetic and mechanosensitive biomarkers that are relevant to specific cell developmental scenarios. © 2018 by John Wiley & Sons, Inc. Copyright © 2018 John Wiley & Sons, Inc.

Mechanics of additively manufactured porous biomaterials based on the rhombicuboctahedron unit cell.

PubMed

Hedayati, R; Sadighi, M; Mohammadi-Aghdam, M; Zadpoor, A A

2016-01-01

Thanks to recent developments in additive manufacturing techniques, it is now possible to fabricate porous biomaterials with arbitrarily complex micro-architectures. Micro-architectures of such biomaterials determine their physical and biological properties, meaning that one could potentially improve the performance of such biomaterials through rational design of micro-architecture. The relationship between the micro-architecture of porous biomaterials and their physical and biological properties has therefore received increasing attention recently. In this paper, we studied the mechanical properties of porous biomaterials made from a relatively unexplored unit cell, namely rhombicuboctahedron. We derived analytical relationships that relate the micro-architecture of such porous biomaterials, i.e. the dimensions of the rhombicuboctahedron unit cell, to their elastic modulus, Poisson's ratio, and yield stress. Finite element models were also developed to validate the analytical solutions. Analytical and numerical results were compared with experimental data from one of our recent studies. It was found that analytical solutions and numerical results show a very good agreement particularly for smaller values of apparent density. The elastic moduli predicted by analytical and numerical models were in very good agreement with experimental observations too. While in excellent agreement with each other, analytical and numerical models somewhat over-predicted the yield stress of the porous structures as compared to experimental data. As the ratio of the vertical struts to the inclined struts, α, approaches zero and infinity, the rhombicuboctahedron unit cell respectively approaches the octahedron (or truncated cube) and cube unit cells. For those limits, the analytical solutions presented here were found to approach the analytic solutions obtained for the octahedron, truncated cube, and cube unit cells, meaning that the presented solutions are generalizations of the analytical solutions obtained for several other types of porous biomaterials. Copyright © 2015 Elsevier Ltd. All rights reserved.

3D printing facilitated scaffold-free tissue unit fabrication.

PubMed

Tan, Yu; Richards, Dylan J; Trusk, Thomas C; Visconti, Richard P; Yost, Michael J; Kindy, Mark S; Drake, Christopher J; Argraves, William Scott; Markwald, Roger R; Mei, Ying

2014-06-01

Tissue spheroids hold great potential in tissue engineering as building blocks to assemble into functional tissues. To date, agarose molds have been extensively used to facilitate fusion process of tissue spheroids. As a molding material, agarose typically requires low temperature plates for gelation and/or heated dispenser units. Here, we proposed and developed an alginate-based, direct 3D mold-printing technology: 3D printing microdroplets of alginate solution into biocompatible, bio-inert alginate hydrogel molds for the fabrication of scaffold-free tissue engineering constructs. Specifically, we developed a 3D printing technology to deposit microdroplets of alginate solution on calcium containing substrates in a layer-by-layer fashion to prepare ring-shaped 3D hydrogel molds. Tissue spheroids composed of 50% endothelial cells and 50% smooth muscle cells were robotically placed into the 3D printed alginate molds using a 3D printer, and were found to rapidly fuse into toroid-shaped tissue units. Histological and immunofluorescence analysis indicated that the cells secreted collagen type I playing a critical role in promoting cell-cell adhesion, tissue formation and maturation.

Three-dimensional Myoblast Aggregates--Effects of Modeled Microgravity

NASA Technical Reports Server (NTRS)

Byerly, Diane; Sognier, M. A.; Marquette, M. L.

2006-01-01

The overall objective of these studies is to elucidate the molecular and cellular alterations that contribute to muscle atrophy in astronauts caused by exposure to microgravity conditions in space. To accomplish this, a three-dimensional model test system was developed using mouse myoblast cells (C2C12). Myoblast cells were grown as three-dimensional aggregates (without scaffolding or other solid support structures) in both modeled microgravity (Rotary Cell Culture System, Synthecon, Inc.) and at unit gravity in coated Petri dishes. Evaluation of H&E stained thin sections of the aggregates revealed the absence of any necrosis. Confocal microscopy evaluations of cells stained with the Live/Dead assay (Molecular Probes) confirmed that viable cells were present throughout the aggregates with an average of only three dead cells observed per aggregate. Preliminary results from gene array analysis (Affymetrix chip U74Av2) showed that approximately 14% of the genes were down regulated (decreased more than 3 fold) and 4% were upregulated in cells exposed to modeled microgravity for 12 hours compared to unit gravity controls. Additional studies using fluorescent phallacidin revealed a decrease in F-actin in the cells exposed to modeled microgravity compared to unit gravity. Myoblast cells grown as aggregates in modeled microgravity exhibited spontaneous differentiation into syncitia while no differentiation was seen in the unit gravity controls. These studies show that 1)the model test system developed is suitable for assessing cellular and molecular alterations in myoblasts; 2) gene expression alterations occur rapidly (within 12 hours) following exposure to modeled microgravity; and 3) modeled microgravity conditions stimulated myoblast cell differentiation. Achieving a greater understanding of the molecular alterations leading to muscle atrophy will eventually enable the development of cell-based countermeasures, which may be valuable for treatment of muscle diseases on Earth and future space explorations.

The effective way

NASA Astrophysics Data System (ADS)

Fruchart, Michel; Vitelli, Vincenzo

2018-03-01

A theoretical framework for the design of so-called perturbative metamaterials, based on weakly interacting unit cells, has led to the experimental demonstration of a quadrupole topological insulator.

A Multi-Functional Microelectrode Array Featuring 59760 Electrodes, 2048 Electrophysiology Channels, Stimulation, Impedance Measurement and Neurotransmitter Detection Channels.

PubMed

Dragas, Jelena; Viswam, Vijay; Shadmani, Amir; Chen, Yihui; Bounik, Raziyeh; Stettler, Alexander; Radivojevic, Milos; Geissler, Sydney; Obien, Marie; Müller, Jan; Hierlemann, Andreas

2017-06-01

Biological cells are characterized by highly complex phenomena and processes that are, to a great extent, interdependent. To gain detailed insights, devices designed to study cellular phenomena need to enable tracking and manipulation of multiple cell parameters in parallel; they have to provide high signal quality and high spatiotemporal resolution. To this end, we have developed a CMOS-based microelectrode array system that integrates six measurement and stimulation functions, the largest number to date. Moreover, the system features the largest active electrode array area to date (4.48×2.43 mm 2 ) to accommodate 59,760 electrodes, while its power consumption, noise characteristics, and spatial resolution (13.5 μm electrode pitch) are comparable to the best state-of-the-art devices. The system includes: 2,048 action-potential (AP, bandwidth: 300 Hz to 10 kHz) recording units, 32 local-field-potential (LFP, bandwidth: 1 Hz to 300 Hz) recording units, 32 current recording units, 32 impedance measurement units, and 28 neurotransmitter detection units, in addition to the 16 dual-mode voltage-only or current/voltage-controlled stimulation units. The electrode array architecture is based on a switch matrix, which allows for connecting any measurement/stimulation unit to any electrode in the array and for performing different measurement/stimulation functions in parallel.

Analysis of the Appropriateness of the Use of Peltier Cells as Energy Sources

PubMed Central

Hájovský, Radovan; Pieš, Martin; Richtár, Lukáš

2016-01-01

The article describes the possibilities of using Peltier cells as an energy source to power the telemetry units, which are used in large-scale monitoring systems as central units, ensuring the collection of data from sensors, processing, and sending to the database server. The article describes the various experiments that were carried out, their progress and results. Based on experiments evaluated, the paper also discusses the possibilities of using various types depending on the temperature difference of the cold and hot sides. PMID:27231913

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nayak, Vikas; Verma, U. P.

Quantum mechanical based first principle calculations have been employed to obtain the unit cell lattice parameters of mercury thiogallate (HgGa{sub 2}S{sub 4}) in defect stannite structure for the first time. For this, we treated HgGa{sub 2}S{sub 4} in two different types of site symmetries in the same space group. In both the cases obtained unit cell parameters are same, which shows the accuracy of present approach. The electronic band structures show the semiconducting behavior in both the cases. The density of states plot are also studied and discussed.

Influence of organic buffers on bacteriocin production by Streptococcus thermophilus ST110.

PubMed

Somkuti, George A; Gilbreth, Stefanie E

2007-08-01

The effect of the organic buffer salts MES, MOPS, and PIPES on the growth of S. thermophilus ST110, medium pH, and accumulation of the antipediococcal bacteriocin thermophilin 110 were evaluated in whey permeate media over a period of 24 h. In nonbuffered medium, thermophilin 110 production at 37 degrees C paralleled the growth of S. thermophilus ST110 and reached a maximum after 8-10 h. Addition of organic buffer salts decreased the drop in medium pH and resulted in increased biomass (dry cells; microg/mL) and higher yields of thermophilin 110 (units/microg cells). The best results were obtained by the addition of 1% (w/v) MES to the medium, which reduced the pH drop to 1.8 units after 10 h of growth (compared to 2.3 pH units in the control) and resulted in a 1.5-fold increase in cell mass (495 microg/mL) and a 7-fold increase in thermophilin 110 yield (77 units/microg dry cells) over the control. The results showed that whey permeate-based media may be suitable for producing large amounts of thermophilin 110 needed for controlling spoilage pediococci in industrial wine and beer fermentations.

The Mastocytosis Society survey on mast cell disorders: patient experiences and perceptions.

PubMed

Jennings, Susan; Russell, Nancy; Jennings, Blair; Slee, Valerie; Sterling, Lisa; Castells, Mariana; Valent, Peter; Akin, Cem

2014-01-01

Mast cell diseases include mastocytosis and mast cell activation syndromes, some of which have been shown to involve clonal defects in mast cells that result in abnormal cellular proliferation or activation. Numerous clinical studies of mastocytosis have been published, but no population-based comprehensive surveys of patients in the United States have been identified. Few mast cell disease specialty centers exist in the United States, and awareness of these mast cell disorders is limited among nonspecialists. Accordingly, information concerning the experiences of the overall estimated population of these patients has been lacking. To identify the experiences and perceptions of patients with mastocytosis, mast cell activation syndromes, and related disorders, The Mastocytosis Society (TMS), a US based patient advocacy, research, and education organization, conducted a survey of its members and other people known or suspected to be part of this patient population. A Web-based survey was publicized through clinics that treat these patients and through TMS's newsletter, Web site, and online blogs. Both online and paper copies of the questionnaire were provided, together with required statements of consent. The first results are presented for 420 patients. These results include demographics, diagnoses, symptoms, allergies, provoking factors of mast cell symptoms, and disease impact. Patients with mastocytosis and mast cell activation syndromes have provided clinical specialists, collaborators, and other patients with information to enable them to explore and deepen their understanding of the experiences and perceptions of people coping with these disorders. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

Wideband Scattering Diffusion by using Diffraction of Periodic Surfaces and Optimized Unit Cell Geometries

PubMed Central

Costa, Filippo; Monorchio, Agostino; Manara, Giuliano

2016-01-01

A methodology to obtain wideband scattering diffusion based on periodic artificial surfaces is presented. The proposed surfaces provide scattering towards multiple propagation directions across an extremely wide frequency band. They comprise unit cells with an optimized geometry and arranged in a periodic lattice characterized by a repetition period larger than one wavelength which induces the excitation of multiple Floquet harmonics. The geometry of the elementary unit cell is optimized in order to minimize the reflection coefficient of the fundamental Floquet harmonic over a wide frequency band. The optimization of FSS geometry is performed through a genetic algorithm in conjunction with periodic Method of Moments. The design method is verified through full-wave simulations and measurements. The proposed solution guarantees very good performance in terms of bandwidth-thickness ratio and removes the need of a high-resolution printing process. PMID:27181841

Peripheral Hole Acceptor Moieties on an Organic Dye Improve Dye‐Sensitized Solar Cell Performance

PubMed Central

Hao, Yan; Gabrielsson, Erik; Lohse, Peter William; Yang, Wenxing; Johansson, Erik M. J.; Hagfeldt, Anders

2015-01-01

Investigation of charge transfer dynamics in dye‐sensitized solar cells is of fundamental interest and the control of these dynamics is a key factor for developing more efficient solar cell devices. One possibility for attenuating losses through recombination between injected electrons and oxidized dye molecules is to move the positive charge further away from the metal oxide surface. For this purpose, a metal‐free dye named E6 is developed, in which the chromophore core is tethered to two external triphenylamine (TPA) units. After photoinduced electron injection into TiO2, the remaining hole is rapidly transferred to a peripheral TPA unit. Electron–hole recombination is slowed down by 30% compared to a reference dye without peripheral TPA units. Furthermore, it is found that the added TPA moieties improve the electron blocking effect of the dye, retarding recombination of electrons from TiO2 to the cobalt‐based electrolyte. PMID:27722076

Micromechanical models for textile structural composites

NASA Technical Reports Server (NTRS)

Marrey, Ramesh V.; Sankar, Bhavani V.

1995-01-01

The objective is to develop micromechanical models for predicting the stiffness and strength properties of textile composite materials. Two models are presented to predict the homogeneous elastic constants and coefficients of thermal expansion of a textile composite. The first model is based on rigorous finite element analysis of the textile composite unit-cell. Periodic boundary conditions are enforced between opposite faces of the unit-cell to simulate deformations accurately. The second model implements the selective averaging method (SAM), which is based on a judicious combination of stiffness and compliance averaging. For thin textile composites, both models can predict the plate stiffness coefficients and plate thermal coefficients. The finite element procedure is extended to compute the thermal residual microstresses, and to estimate the initial failure envelope for textile composites.

A Circular Polarizer with Beamforming Feature Based on Frequency Selective Surfaces

NASA Astrophysics Data System (ADS)

Yin, Jia Yuan; Wan, Xiang; Ren, Jian; Cui, Tie Jun

2017-01-01

We propose a circular polarizer with beamforming features based on frequency selective surface (FSS), in which a modified anchor-shaped unit cell is used to reach the circular polarizer function. The beamforming characteristic is realized by a particular design of the unit-phase distribution, which is obtained by varying the scale of the unit cell. Instead of using plane waves, a horn antenna is designed to feed the phase-variant FSS. The proposed two-layer FSS is fabricated and measured to verify the design. The measured results show that the proposed structure can convert the linearly polarized waves to circularly polarized waves. Compared with the feeding horn antenna, the transmitted beam of the FSS-added horn is 14.43° broader in one direction, while 3.77° narrower in the orthogonal direction. To our best knowledge, this is the first time to realize circular polarizer with beamforming as the extra function based on FSS, which is promising in satellite and communication systems for potential applications due to its simple design and good performance.

Solid Polymer Electrolyte (SPE) fuel cell technology program

NASA Technical Reports Server (NTRS)

1979-01-01

The overall objectives of the Phase IV Solid Polymer Electrolyte Fuel Cell Technology Program were to: (1) establish fuel cell life and performance at temperatures, pressures and current densities significantly higher than those previously demonstrated; (2) provide the ground work for a space energy storage system based on the solid polymer electrolyte technology (i.e., regenerative H2/O2 fuel cell); (3) design, fabricate and test evaluate a full-scale single cell unit. During this phase, significant progress was made toward the accomplishment of these objectives.

Meso-Scale Finite Element Analysis of Mechanical Behavior of 3D Braided Composites Subjected to Biaxial Tension Loadings

NASA Astrophysics Data System (ADS)

Zhang, Chao; Curiel-Sosa, Jose L.; Bui, Tinh Quoc

2018-04-01

In many engineering applications, 3D braided composites are designed for primary loading-bearing structures, and they are frequently subjected to multi-axial loading conditions during service. In this paper, a unit-cell based finite element model is developed for assessment of mechanical behavior of 3D braided composites under different biaxial tension loadings. To predict the damage initiation and evolution of braiding yarns and matrix in the unit-cell, we thus propose an anisotropic damage model based on Murakami damage theory in conjunction with Hashin failure criteria and maximum stress criteria. To attain exact stress ratio, force loading mode of periodic boundary conditions which never been attempted before is first executed to the unit-cell model to apply the biaxial tension loadings. The biaxial mechanical behaviors, such as the stress distribution, tensile modulus and tensile strength are analyzed and discussed. The damage development of 3D braided composites under typical biaxial tension loadings is simulated and the damage mechanisms are revealed in the simulation process. The present study generally provides a new reference to the meso-scale finite element analysis (FEA) of multi-axial mechanical behavior of other textile composites.

The high throughput biomedicine unit at the institute for molecular medicine Finland: high throughput screening meets precision medicine.

PubMed

Pietiainen, Vilja; Saarela, Jani; von Schantz, Carina; Turunen, Laura; Ostling, Paivi; Wennerberg, Krister

2014-05-01

The High Throughput Biomedicine (HTB) unit at the Institute for Molecular Medicine Finland FIMM was established in 2010 to serve as a national and international academic screening unit providing access to state of the art instrumentation for chemical and RNAi-based high throughput screening. The initial focus of the unit was multiwell plate based chemical screening and high content microarray-based siRNA screening. However, over the first four years of operation, the unit has moved to a more flexible service platform where both chemical and siRNA screening is performed at different scales primarily in multiwell plate-based assays with a wide range of readout possibilities with a focus on ultraminiaturization to allow for affordable screening for the academic users. In addition to high throughput screening, the equipment of the unit is also used to support miniaturized, multiplexed and high throughput applications for other types of research such as genomics, sequencing and biobanking operations. Importantly, with the translational research goals at FIMM, an increasing part of the operations at the HTB unit is being focused on high throughput systems biological platforms for functional profiling of patient cells in personalized and precision medicine projects.

Effect of Cord Blood Processing on Transplant Outcomes after Single Myeloablative Umbilical Cord Blood Transplantation

PubMed Central

Ballen, Karen K.; Logan, Brent R.; Laughlin, Mary J.; He, Wensheng; Ambruso, Daniel R.; Armitage, Susan E.; Beddard, Rachel L.; Bhatla, Deepika; Hwang, William Y.K.; Kiss, Joseph E.; Koegler, Gesine; Kurtzberg, Joanne; Nagler, Arnon; Oh, David; Petz, Lawrence D.; Price, Thomas H.; Quinones, Ralph R.; Ratanatharathorn, Voravit; Rizzo, J. Douglas; Sazama, Kathleen; Scaradavou, Andromachi; Schuster, Michael W.; Sender, Leonard S.; Shpall, Elizabeth J.; Spellman, Stephen R.; Sutton, Millicent; Weitekamp, Lee Ann; Wingard, John R.; Eapen, Mary

2015-01-01

Variations in cord blood manufacturing and administration are common, and the optimal practice, not known. We compared processing and banking practices at 16 public cord blood banks (CBB) in the United States, and assessed transplant outcomes on 530 single umbilical cord blood (UCB) myeloablative transplantations for hematologic malignancies, facilitated by these banks. UCB banking practices were separated into three mutually exclusive groups based on whether processing was automated or manual; units were plasma and red blood cell reduced or buffy coat production method or plasma reduced. Compared to the automated processing system for units, the day-28 neutrophil recovery was significantly lower after transplantation of units that were manually processed and plasma reduced (red cell replete) (odds ratio [OR] 0.19 p=0.001) or plasma and red cell reduced (OR 0.54, p=0.05). Day-100 survival did not differ by CBB. However, day-100 survival was better with units that were thawed with the dextran-albumin wash method compared to the “no wash” or “dilution only” techniques (OR 1.82, p=0.04). In conclusion, CBB processing has no significant effect on early (day 100) survival despite differences in kinetics of neutrophil recovery. PMID:25543094

Three-dimensional finite element modeling of pericellular matrix and cell mechanics in the nucleus pulposus of the intervertebral disk based on in situ morphology.

PubMed

Cao, Li; Guilak, Farshid; Setton, Lori A

2011-02-01

Nucleus pulposus (NP) cells of the intervertebral disk (IVD) have unique morphological characteristics and biologic responses to mechanical stimuli that may regulate maintenance and health of the IVD. NP cells reside as single cell, paired or multiple cells in a contiguous pericellular matrix (PCM), whose structure and properties may significantly influence cell and extracellular matrix mechanics. In this study, a computational model was developed to predict the stress-strain, fluid pressure and flow fields for cells and their surrounding PCM in the NP using three-dimensional (3D) finite element models based on the in situ morphology of cell-PCM regions of the mature rat NP, measured using confocal microscopy. Three-dimensional geometries of the extracellular matrix and representative cell-matrix units were used to construct 3D finite element models of the structures as isotropic and biphasic materials. In response to compressive strain of the extracellular matrix, NP cells and PCM regions were predicted to experience volumetric strains that were 1.9-3.7 and 1.4-2.1 times greater than the extracellular matrix, respectively. Volumetric and deviatoric strain concentrations were generally found at the cell/PCM interface, while von Mises stress concentrations were associated with the PCM/extracellular matrix interface. Cell-matrix units containing greater cell numbers were associated with higher peak cell strains and lower rates of fluid pressurization upon loading. These studies provide new model predictions for micromechanics of NP cells that can contribute to an understanding of mechanotransduction in the IVD and its changes with aging and degeneration.

Computational Homogenization of Mechanical Properties for Laminate Composites Reinforced with Thin Film Made of Carbon Nanotubes

NASA Astrophysics Data System (ADS)

El Moumen, A.; Tarfaoui, M.; Lafdi, K.

2018-06-01

Elastic properties of laminate composites based Carbone Nanotubes (CNTs), used in military applications, were estimated using homogenization techniques and compared to the experimental data. The composite consists of three phases: T300 6k carbon fibers fabric with 5HS (satin) weave, baseline pure Epoxy matrix and CNTs added with 0.5%, 1%, 2% and 4%. Two step homogenization methods based RVE model were employed. The objective of this paper is to determine the elastic properties of structure starting from the knowledge of those of constituents (CNTs, Epoxy and carbon fibers fabric). It is assumed that the composites have a geometric periodicity and the homogenization model can be represented by a representative volume element (RVE). For multi-scale analysis, finite element modeling of unit cell based two step homogenization method is used. The first step gives the properties of thin film made of epoxy and CNTs and the second is used for homogenization of laminate composite. The fabric unit cell is chosen using a set of microscopic observation and then identified by its ability to enclose the characteristic periodic repeat in the fabric weave. The unit cell model of 5-Harness satin weave fabric textile composite is identified for numerical approach and their dimensions are chosen based on some microstructural measurements. Finally, a good comparison was obtained between the predicted elastic properties using numerical homogenization approach and the obtained experimental data with experimental tests.

Computational Homogenization of Mechanical Properties for Laminate Composites Reinforced with Thin Film Made of Carbon Nanotubes

NASA Astrophysics Data System (ADS)

El Moumen, A.; Tarfaoui, M.; Lafdi, K.

2017-08-01

Elastic properties of laminate composites based Carbone Nanotubes (CNTs), used in military applications, were estimated using homogenization techniques and compared to the experimental data. The composite consists of three phases: T300 6k carbon fibers fabric with 5HS (satin) weave, baseline pure Epoxy matrix and CNTs added with 0.5%, 1%, 2% and 4%. Two step homogenization methods based RVE model were employed. The objective of this paper is to determine the elastic properties of structure starting from the knowledge of those of constituents (CNTs, Epoxy and carbon fibers fabric). It is assumed that the composites have a geometric periodicity and the homogenization model can be represented by a representative volume element (RVE). For multi-scale analysis, finite element modeling of unit cell based two step homogenization method is used. The first step gives the properties of thin film made of epoxy and CNTs and the second is used for homogenization of laminate composite. The fabric unit cell is chosen using a set of microscopic observation and then identified by its ability to enclose the characteristic periodic repeat in the fabric weave. The unit cell model of 5-Harness satin weave fabric textile composite is identified for numerical approach and their dimensions are chosen based on some microstructural measurements. Finally, a good comparison was obtained between the predicted elastic properties using numerical homogenization approach and the obtained experimental data with experimental tests.

Prediction of novel stable Fe-V-Si ternary phase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Manh Cuong; Chen, Chong; Zhao, Xin

Genetic algorithm searches based on a cluster expansion model are performed to search for stable phases of Fe-V-Si ternary. Here, we identify a new thermodynamically, dynamically and mechanically stable ternary phase of Fe 5V 2Si with 2 formula units in a tetragonal unit cell. The formation energy of this new ternary phase is -36.9 meV/atom below the current ternary convex hull. The magnetic moment of Fe in the new structure varies from -0.30-2.52 μ B depending strongly on the number of Fe nearest neighbors. The total magnetic moment is 10.44 μ B/unit cell for new Fe 5V 2Si structure andmore » the system is ordinarily metallic.« less

Prediction of novel stable Fe-V-Si ternary phase

DOE PAGES

Nguyen, Manh Cuong; Chen, Chong; Zhao, Xin; ...

2018-10-28

Genetic algorithm searches based on a cluster expansion model are performed to search for stable phases of Fe-V-Si ternary. Here, we identify a new thermodynamically, dynamically and mechanically stable ternary phase of Fe 5V 2Si with 2 formula units in a tetragonal unit cell. The formation energy of this new ternary phase is -36.9 meV/atom below the current ternary convex hull. The magnetic moment of Fe in the new structure varies from -0.30-2.52 μ B depending strongly on the number of Fe nearest neighbors. The total magnetic moment is 10.44 μ B/unit cell for new Fe 5V 2Si structure andmore » the system is ordinarily metallic.« less

Handedness in shearing auxetics creates rigid and compliant structures

NASA Astrophysics Data System (ADS)

Lipton, Jeffrey Ian; MacCurdy, Robert; Manchester, Zachary; Chin, Lillian; Cellucci, Daniel; Rus, Daniela

2018-05-01

In nature, repeated base units produce handed structures that selectively bond to make rigid or compliant materials. Auxetic tilings are scale-independent frameworks made from repeated unit cells that expand under tension. We discovered how to produce handedness in auxetic unit cells that shear as they expand by changing the symmetries and alignments of auxetic tilings. Using the symmetry and alignment rules that we developed, we made handed shearing auxetics that tile planes, cylinders, and spheres. By compositing the handed shearing auxetics in a manner inspired by keratin and collagen, we produce both compliant structures that expand while twisting and deployable structures that can rigidly lock. This work opens up new possibilities in designing chemical frameworks, medical devices like stents, robotic systems, and deployable engineering structures.

Traction patterns of tumor cells.

PubMed

Ambrosi, D; Duperray, A; Peschetola, V; Verdier, C

2009-01-01

The traction exerted by a cell on a planar deformable substrate can be indirectly obtained on the basis of the displacement field of the underlying layer. The usual methodology used to address this inverse problem is based on the exploitation of the Green tensor of the linear elasticity problem in a half space (Boussinesq problem), coupled with a minimization algorithm under force penalization. A possible alternative strategy is to exploit an adjoint equation, obtained on the basis of a suitable minimization requirement. The resulting system of coupled elliptic partial differential equations is applied here to determine the force field per unit surface generated by T24 tumor cells on a polyacrylamide substrate. The shear stress obtained by numerical integration provides quantitative insight of the traction field and is a promising tool to investigate the spatial pattern of force per unit surface generated in cell motion, particularly in the case of such cancer cells.

Improvements in and actual performance of the Plant Experiment Unit onboard Kibo, the Japanese experiment module on the international space station

NASA Astrophysics Data System (ADS)

Yano, Sachiko; Kasahara, Haruo; Masuda, Daisuke; Tanigaki, Fumiaki; Shimazu, Toru; Suzuki, Hiromi; Karahara, Ichirou; Soga, Kouichi; Hoson, Takayuki; Tayama, Ichiro; Tsuchiya, Yoshikazu; Kamisaka, Seiichiro

2013-03-01

In 2004, Japan Aerospace Exploration Agency developed the engineered model of the Plant Experiment Unit and the Cell Biology Experiment Facility. The Plant Experiment Unit was designed to be installed in the Cell Biology Experiment Facility and to support the seed-to-seed life cycle experiment of Arabidopsis plants in space in the project named Space Seed. Ground-based experiments to test the Plant Experiment Unit showed that the unit needed further improvement of a system to control the water content of a seedbed using an infrared moisture analyzer and that it was difficult to keep the relative humidity inside the Plant Experiment Unit between 70 and 80% because the Cell Biology Experiment Facility had neither a ventilation system nor a dehumidifying system. Therefore, excess moisture inside the Cell Biology Experiment Facility was removed with desiccant bags containing calcium chloride. Eight flight models of the Plant Experiment Unit in which dry Arabidopsis seeds were fixed to the seedbed with gum arabic were launched to the International Space Station in the space shuttle STS-128 (17A) on August 28, 2009. Plant Experiment Unit were installed in the Cell Biology Experiment Facility with desiccant boxes, and then the Space Seed experiment was started in the Japanese Experiment Module, named Kibo, which was part of the International Space Station, on September 10, 2009 by watering the seedbed and terminated 2 months later on November 11, 2009. On April 19, 2010, the Arabidopsis plants harvested in Kibo were retrieved and brought back to Earth by the space shuttle mission STS-131 (19A). The present paper describes the Space Seed experiment with particular reference to the development of the Plant Experiment Unit and its actual performance in Kibo onboard the International Space Station. Downlinked images from Kibo showed that the seeds had started germinating 3 days after the initial watering. The plants continued growing, producing rosette leaves, inflorescence stems, flowers, and fruits in the Plant Experiment Unit. In addition, the senescence of rosette leaves was found to be delayed in microgravity.

A Compact Energy Harvesting System for Outdoor Wireless Sensor Nodes Based on a Low-Cost In Situ Photovoltaic Panel Characterization-Modelling Unit.

PubMed

Antolín, Diego; Medrano, Nicolás; Calvo, Belén; Martínez, Pedro A

2017-08-04

This paper presents a low-cost high-efficiency solar energy harvesting system to power outdoor wireless sensor nodes. It is based on a Voltage Open Circuit (VOC) algorithm that estimates the open-circuit voltage by means of a multilayer perceptron neural network model trained using local experimental characterization data, which are acquired through a novel low cost characterization system incorporated into the deployed node. Both units-characterization and modelling-are controlled by the same low-cost microcontroller, providing a complete solution which can be understood as a virtual pilot cell, with identical characteristics to those of the specific small solar cell installed on the sensor node, that besides allows an easy adaptation to changes in the actual environmental conditions, panel aging, etc. Experimental comparison to a classical pilot panel based VOC algorithm show better efficiency under the same tested conditions.

Purification of rat megakaryocyte colony-forming cells using a monoclonal antibody against rat platelet glycoprotein IIb/IIIa.

PubMed

Miyazaki, H; Inoue, H; Yanagida, M; Horie, K; Mikayama, T; Ohashi, H; Nishikawa, M; Suzuki, T; Sudo, T

1992-08-01

We recently reported the production and characterization of four monoclonal antibodies (MoAbs) against rat platelet glycoprotein IIb/IIIa (GPIIb/IIIa). In this study we developed a simple and efficient three-step procedure, based on positive selection by immunoadsorption (panning) using one MoAb, P55, to purify rat megakaryocyte colony-forming cells (megakaryocyte colony-forming units, CFU-MK) from normal bone marrow. Cells obtained after each step were assayed for their ability to form megakaryocyte colonies in the presence of Concanavalin A (Con A)-stimulated rat spleen cell-conditioned medium in soft agar cultures. Marrow cells were first separated on discontinuous Percoll gradients. Cells sedimented at densities between 1.063 and 1.082 g/ml were depleted of cells adherent to plastic tissue culture dishes. The nonadherent cells were further incubated on dishes coated with P55 MoAb. CFU-MK were enriched about 50-fold in the adsorbed cell fraction. This sequential fractionation procedure resulted in a 345-fold (range 276 to 412-fold) enrichment of rat CFU-MK over whole bone marrow cells. The average cloning efficiency of CFU-MK in the final fraction was about 7% (range 5%-9.2%) of the nucleated cells. The overall recovery of CFU-MK averaged 20% (range 9%-29%). The panning step provided a 46-fold enrichment of megakaryocyte burst-forming cells (megakaryocyte burst-forming units, BFU-MK), whose average cloning efficiency in the post-panning fraction was 0.14% (range 0.07%-0.2%). In addition, erythroid burst-forming cells (erythroid burst-forming units, BFU-E) were also significantly enriched by panning, but to a lesser degree than BFU-MK and CFU-MK. By contrast, granulocyte-macrophage colony-forming cells (granulocyte-macrophage colony-forming units, CFU-GM) and erythroid colony-forming cells (erythroid colony-forming units, CFU-E) were not enriched by panning. CFU-MK obtained after panning formed megakaryocyte colonies in the presence of recombinant rat interleukin 3 (rIL-3), mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF), or human erythropoietin (hEPO), as has been reported for murine CFU-MK in whole marrow cells. The highly enriched populations of rat CFU-MK should thus provide a basis for the further study of the regulation of megakaryocytopoiesis.

Tuning of quantum entanglement in molecular quantum cellular automata based on mixed-valence tetrameric units.

PubMed

Palii, Andrew; Tsukerblat, Boris

2016-10-25

In this article we consider two coupled tetrameric mixed-valence (MV) units accommodating electron pairs, which play the role of cells in molecular quantum cellular automata. It is supposed that the Coulombic interaction between instantly localized electrons within the cell markedly inhibits the transfer processes between the redox centers. Under this condition, as well as due to the vibronic localization of the electron pair, the cell can encode binary information, which is controlled by neighboring cells. We show that under certain conditions the two low-lying vibronic spin levels of the cell (ground and first excited states) can be regarded as originating from an effective spin-spin interaction. This is shown to depend on the internal parameters of the cell as well as on the induced polarization. Within this simplified two-level picture we evaluate the quantum entanglement in the system represented by the two electrons in the cell and show how the entanglement within the cell and concurrence can be controlled via polarization of the neighboring cells and temperature.

SSH2S: Hydrogen storage in complex hydrides for an auxiliary power unit based on high temperature proton exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Baricco, Marcello; Bang, Mads; Fichtner, Maximilian; Hauback, Bjorn; Linder, Marc; Luetto, Carlo; Moretto, Pietro; Sgroi, Mauro

2017-02-01

The main objective of the SSH2S (Fuel Cell Coupled Solid State Hydrogen Storage Tank) project was to develop a solid state hydrogen storage tank based on complex hydrides and to fully integrate it with a High Temperature Proton Exchange Membrane (HT-PEM) fuel cell stack. A mixed lithium amide/magnesium hydride system was used as the main storage material for the tank, due to its high gravimetric storage capacity and relatively low hydrogen desorption temperature. The mixed lithium amide/magnesium hydride system was coupled with a standard intermetallic compound to take advantage of its capability to release hydrogen at ambient temperature and to ensure a fast start-up of the system. The hydrogen storage tank was designed to feed a 1 kW HT-PEM stack for 2 h to be used for an Auxiliary Power Unit (APU). A full thermal integration was possible thanks to the high operation temperature of the fuel cell and to the relative low temperature (170 °C) for hydrogen release from the mixed lithium amide/magnesium hydride system.

From Empiricism to Total Quality Management in Greek Education

NASA Astrophysics Data System (ADS)

Karavasilis, Ioannis; Samoladas, Ioannis; Nedos, Apostolos

Nowadays the education system in Greece moves towards democratization and decentralization. School unit is the cell and the base of the education system. Principal's role is highly demanding, multi-dimensional, and a critical determinant of school performance and effectiveness. The paper proposes an effective organizational plan of school units in Primary Education based on basic administration processes and Total Quality Management. Using theory of emotional intelligence and Blake-Mouton's grid it emphasizes the impact of Principal's leadership on democratizing the school unit, on creating a safe and secure environment and positive school climate and motivating teachers committee to participate in the decision making process.

Device for monitoring cell voltage

DOEpatents

Doepke, Matthias [Garbsen, DE; Eisermann, Henning [Edermissen, DE

2012-08-21

A device for monitoring a rechargeable battery having a number of electrically connected cells includes at least one current interruption switch for interrupting current flowing through at least one associated cell and a plurality of monitoring units for detecting cell voltage. Each monitoring unit is associated with a single cell and includes a reference voltage unit for producing a defined reference threshold voltage and a voltage comparison unit for comparing the reference threshold voltage with a partial cell voltage of the associated cell. The reference voltage unit is electrically supplied from the cell voltage of the associated cell. The voltage comparison unit is coupled to the at least one current interruption switch for interrupting the current of at least the current flowing through the associated cell, with a defined minimum difference between the reference threshold voltage and the partial cell voltage.

Modeling and control of fuel cell based distributed generation systems

NASA Astrophysics Data System (ADS)

Jung, Jin Woo

This dissertation presents circuit models and control algorithms of fuel cell based distributed generation systems (DGS) for two DGS topologies. In the first topology, each DGS unit utilizes a battery in parallel to the fuel cell in a standalone AC power plant and a grid-interconnection. In the second topology, a Z-source converter, which employs both the L and C passive components and shoot-through zero vectors instead of the conventional DC/DC boost power converter in order to step up the DC-link voltage, is adopted for a standalone AC power supply. In Topology 1, two applications are studied: a standalone power generation (Single DGS Unit and Two DGS Units) and a grid-interconnection. First, dynamic model of the fuel cell is given based on electrochemical process. Second, two full-bridge DC to DC converters are adopted and their controllers are designed: an unidirectional full-bridge DC to DC boost converter for the fuel cell and a bidirectional full-bridge DC to DC buck/boost converter for the battery. Third, for a three-phase DC to AC inverter without or with a Delta/Y transformer, a discrete-time state space circuit model is given and two discrete-time feedback controllers are designed: voltage controller in the outer loop and current controller in the inner loop. And last, for load sharing of two DGS units and power flow control of two DGS units or the DGS connected to the grid, real and reactive power controllers are proposed. Particularly, for the grid-connected DGS application, a synchronization issue between an islanding mode and a paralleling mode to the grid is investigated, and two case studies are performed. To demonstrate the proposed circuit models and control strategies, simulation test-beds using Matlab/Simulink are constructed for each configuration of the fuel cell based DGS with a three-phase AC 120 V (L-N)/60 Hz/50 kVA and various simulation results are presented. In Topology 2, this dissertation presents system modeling, modified space vector PWM implementation (MSVPWM) and design of a closed-loop controller of the Z-source converter which utilizes L and C components and shoot-through zero vectors for the standalone AC power generation. The fuel cell system is modeled by an electrical R-C circuit in order to include slow dynamics of the fuel cells and a voltage-current characteristic of a cell is also considered. A discrete-time state space model is derived to implement digital control and a space vector pulse-width modulation (SVPWM) technique is modified to realize the shoot-through zero vectors that boost the DC-link voltage. Also, three discrete-time feedback controllers are designed: a discrete-time optimal voltage controller, a discrete-time sliding mode current controller, and a discrete-time PI DC-link voltage controller. Furthermore, an asymptotic observer is used to reduce the number of sensors and enhance the reliability of the system. To demonstrate the analyzed circuit model and proposed control strategy, various simulation results using Matlab/Simulink are presented under both light/heavy loads and linear/nonlinear loads for a three-phase AC 208 V (L-L)/60 Hz/10 kVA.

Reprogramming One-Carbon Metabolic Pathways To Decouple l-Serine Catabolism from Cell Growth in Corynebacterium glutamicum.

PubMed

Zhang, Yun; Shang, Xiuling; Lai, Shujuan; Zhang, Yu; Hu, Qitiao; Chai, Xin; Wang, Bo; Liu, Shuwen; Wen, Tingyi

2018-02-16

l-Serine, the principal one-carbon source for DNA biosynthesis, is difficult for microorganisms to accumulate due to the coupling of l-serine catabolism and microbial growth. Here, we reprogrammed the one-carbon unit metabolic pathways in Corynebacterium glutamicum to decouple l-serine catabolism from cell growth. In silico model-based simulation showed a negative influence on glyA-encoding serine hydroxymethyltransferase flux with l-serine productivity. Attenuation of glyA transcription resulted in increased l-serine accumulation, and a decrease in purine pools, poor growth and longer cell shapes. The gcvTHP-encoded glycine cleavage (Gcv) system from Escherichia coli was introduced into C. glutamicum, allowing glycine-derived 13 CH 2 to be assimilated into intracellular purine synthesis, which resulted in an increased amount of one-carbon units. Gcv introduction not only restored cell viability and morphology but also increased l-serine accumulation. Moreover, comparative proteomic analysis indicated that abundance changes of the enzymes involved in one-carbon unit cycles might be responsible for maintaining one-carbon unit homeostasis. Reprogramming of the one-carbon metabolic pathways allowed cells to reach a comparable growth rate to accumulate 13.21 g/L l-serine by fed-batch fermentation in minimal medium. This novel strategy provides new insights into the regulation of cellular properties and essential metabolite accumulation by introducing an extrinsic pathway.

Finite element analysis of the stiffness of fabric reinforced composites

NASA Technical Reports Server (NTRS)

Foye, R. L.

1992-01-01

The objective of this work is the prediction of all three dimensional elastic moduli of textile fabric reinforced composites. The analysis is general enough for use with complex reinforcing geometries and capable of subsequent improvements. It places no restrictions on fabric microgeometry except that the unit cell be determinate and rectangular. The unit cell is divided into rectangular subcells in which the reinforcing geometries are easier to define and analyze. The analysis, based on inhomogeneous finite elements, is applied to a variety of weave, braid, and knit reinforced composites. Some of these predictions are correlated to test data.

A multi-level simulation platform of natural gas internal reforming solid oxide fuel cell-gas turbine hybrid generation system - Part II. Balancing units model library and system simulation

NASA Astrophysics Data System (ADS)

Bao, Cheng; Cai, Ningsheng; Croiset, Eric

2011-10-01

Following our integrated hierarchical modeling framework of natural gas internal reforming solid oxide fuel cell (IRSOFC), this paper firstly introduces the model libraries of main balancing units, including some state-of-the-art achievements and our specific work. Based on gPROMS programming code, flexible configuration and modular design are fully realized by specifying graphically all unit models in each level. Via comparison with the steady-state experimental data of Siemens-Westinghouse demonstration system, the in-house multi-level SOFC-gas turbine (GT) simulation platform is validated to be more accurate than the advanced power system analysis tool (APSAT). Moreover, some units of the demonstration system are designed reversely for analysis of a typically part-load transient process. The framework of distributed and dynamic modeling in most of units is significant for the development of control strategies in the future.

Synthesis and Photovoltaic Properties of a Copolymer based on thieno [2, 3-f] benzofuran and thienopyrroledione

NASA Astrophysics Data System (ADS)

Gao, Yueyue; Yang, Yulin; Zhang, Yong

2017-12-01

A novel donor-acceptor type conjugated polymer PTBFTPD based on two-dimensional (2D) conjugated alkylthienyl substituted thieno[2,3-f]benzofuran (TBF) and thienopyrroledione (TPD) unit, was synthesized and applied as donor material for bulk heterojunction solar cells. The novol polymer possesses a narrow bandgap of 1.83 eV, a deep HOMO energy level (-5.64 eV) and a closer π-π stacking. After conventional devices were fabricated using PTBFTPD as donor blending with PC70BM as acceptor, a power conversion efficiency (PCE) of 4.33% with a high open circuit voltage (Voc) of 1.09 V was obtained. The result indicates the promising potential of thieno [2, 3-f] benzofuran unit for high efficient polymer solar cells with a high voltage.

Learning LM Specificity for Ganglion Cells

NASA Technical Reports Server (NTRS)

Ahumada, Albert J.

2015-01-01

Unsupervised learning models have been proposed based on experience (Ahumada and Mulligan, 1990;Wachtler, Doi, Lee and Sejnowski, 2007) that allow the cortex to develop units with LM specific color opponent receptive fields like the blob cells reported by Hubel and Wiesel on the basis of visual experience. These models used ganglion cells with LM indiscriminate wiring as inputs to the learning mechanism, which was presumed to occur at the cortical level.

Global Population Distribution (1990),Terrestrial Area and Country Name Information on a One by One Degree Grid Cell Basis

DOE Data Explorer

Li, Yi-Fan [Canadian Global Emissions Inventory Centre, Downsview, Ontario (Canada); Brenkert, A. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

1996-01-01

This data base contains gridded (one degree by one degree) information on the world-wide distribution of the population for 1990 and country-specific information on the percentage of the country's population present in each grid cell (Li, 1996a). Secondly, the data base contains the percentage of a country's total area in a grid cell and the country's percentage of the grid cell that is terrestrial (Li, 1996b). Li (1996b) also developed an indicator signifying how many countries are represented in a grid cell and if a grid cell is part of the sea; this indicator is only relevant for the land, countries, and sea-partitioning information of the grid cell. Thirdly, the data base includes the latitude and longitude coordinates of each grid cell; a grid code number, which is a translation of the latitude/longitude value and is used in the Global Emission Inventory Activity (GEIA) data bases; the country or region's name; and the United Nations three-digit country code that represents that name.

Sensitivity of solar-cell performance to atmospheric variables. 2: Dissimilar cells at several locations

NASA Technical Reports Server (NTRS)

Klucher, T. M.; Hart, R. E.

1976-01-01

Several solar cells having dissimilar spectral response curves and cell construction were measured at various locations in the United States to determine sensitivity of cell performance to atmospheric water vapor and turbidity. The locations selected represent a broad range of summer atmospheric conditions, from clear and dry to turbid and humid. Cell short circuit current under direct normal incidence sunlight, the intensity, water vapor and turbidity were measured. Regression equations were developed from the limited data base in order to provide a single method of prediction of cell current sensitivity to the atmospheric variables.

Tumor invasion unit in gastric cancer revealed by QDs-based in situ molecular imaging and multispectral analysis.

PubMed

Hu, Wen-Qing; Fang, Min; Zhao, Hao-Liang; Yan, Shu-Guang; Yuan, Jing-Ping; Peng, Chun-Wei; Yang, Gui-Fang; Li, Yan; Li, Jian-Ding

2014-04-01

In tumor tissues, cancer cells, tumor infiltrating macrophages and tumor neo-vessels in close spatial vicinity with one another form tumor invasion unit, which is a biologically important tumor microenvironment of metastasis to facilitate cancer invasion and metastasis. Establishing an in situ molecular imaging technology to simultaneously reveal these three components is essential for the in-depth investigation of tumor invasion unit. In this report, we have developed a computer-aided algorithm by quantum dots (QDs)-based multiplexed molecular imaging technique for such purpose. A series of studies on gastric cancer tumor tissues demonstrated that the tumor invasion unit was correlated with major unfavorable pathological features and worse clinical outcomes, which illustrated the significantly negative impacts and predictive power of tumor invasion unit on patient overall survival. This study confirmed the technical advantages of QDs-based in situ and simultaneous molecular imaging of key cancer molecules to gain deeper insights into the biology of cancer invasion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Donor polymer design enables efficient non-fullerene organic solar cells

PubMed Central

Li, Zhengke; Jiang, Kui; Yang, Guofang; Lai, Joshua Yuk Lin; Ma, Tingxuan; Zhao, Jingbo; Ma, Wei; Yan, He

2016-01-01

To achieve efficient organic solar cells, the design of suitable donor–acceptor couples is crucially important. State-of-the-art donor polymers used in fullerene cells may not perform well when they are combined with non-fullerene acceptors, thus new donor polymers need to be developed. Here we report non-fullerene organic solar cells with efficiencies up to 10.9%, enabled by a novel donor polymer that exhibits strong temperature-dependent aggregation but with intentionally reduced polymer crystallinity due to the introduction of a less symmetric monomer unit. Our comparative study shows that an analogue polymer with a C2 symmetric monomer unit yields highly crystalline polymer films but less efficient non-fullerene cells. Based on a monomer with a mirror symmetry, our best donor polymer exhibits reduced crystallinity, yet such a polymer matches better with small molecular acceptors. This study provides important insights to the design of donor polymers for non-fullerene organic solar cells. PMID:27782112

Study on Topology Optimization Design, Manufacturability, and Performance Evaluation of Ti-6Al-4V Porous Structures Fabricated by Selective Laser Melting (SLM)

PubMed Central

Xu, Yangli; Zhang, Dongyun; Zhou, Yan; Wang, Weidong; Cao, Xuanyang

2017-01-01

The combination of topology optimization (TOP) and selective laser melting (SLM) provides the possibility of fabricating the complex, lightweight and high performance geometries overcoming the traditional manufacturing “bottleneck”. This paper evaluates the biomechanical properties of porous structures with porosity from 40% to 80% and unit cell size from 2 to 8 mm, which are designed by TOP and manufactured by SLM. During manufacturability exploration, three typical structures including spiral structure, arched bridge structure and structures with thin walls and small holes are abstracted and investigated, analyzing their manufacturing limits and forming reason. The property tests show that dynamic elastic modulus and compressive strength of porous structures decreases with increases of porosity (constant unit cell size) or unit cell size (constant porosity). Based on the Gibson-Ashby model, three failure models are proposed to describe their compressive behavior, and the structural parameter λ is used to evaluate the stability of the porous structure. Finally, a numerical model for the correlation between porous structural parameters (unit cell size and porosity) and elastic modulus is established, which provides a theoretical reference for matching the elastic modulus of human bones from different age, gender and skeletal sites during innovative medical implant design and manufacturing. PMID:28880229

Study on Topology Optimization Design, Manufacturability, and Performance Evaluation of Ti-6Al-4V Porous Structures Fabricated by Selective Laser Melting (SLM).

PubMed

Xu, Yangli; Zhang, Dongyun; Zhou, Yan; Wang, Weidong; Cao, Xuanyang

2017-09-07

The combination of topology optimization (TOP) and selective laser melting (SLM) provides the possibility of fabricating the complex, lightweight and high performance geometries overcoming the traditional manufacturing "bottleneck". This paper evaluates the biomechanical properties of porous structures with porosity from 40% to 80% and unit cell size from 2 to 8 mm, which are designed by TOP and manufactured by SLM. During manufacturability exploration, three typical structures including spiral structure, arched bridge structure and structures with thin walls and small holes are abstracted and investigated, analyzing their manufacturing limits and forming reason. The property tests show that dynamic elastic modulus and compressive strength of porous structures decreases with increases of porosity (constant unit cell size) or unit cell size (constant porosity). Based on the Gibson-Ashby model, three failure models are proposed to describe their compressive behavior, and the structural parameter λ is used to evaluate the stability of the porous structure. Finally, a numerical model for the correlation between porous structural parameters (unit cell size and porosity) and elastic modulus is established, which provides a theoretical reference for matching the elastic modulus of human bones from different age, gender and skeletal sites during innovative medical implant design and manufacturing.

Use of an adaptable cell culture kit for performing lymphocyte and monocyte cell cultures in microgravity

NASA Technical Reports Server (NTRS)

Hatton, J. P.; Lewis, M. L.; Roquefeuil, S. B.; Chaput, D.; Cazenave, J. P.; Schmitt, D. A.

1998-01-01

The results of experiments performed in recent years on board facilities such as the Space Shuttle/Spacelab have demonstrated that many cell systems, ranging from simple bacteria to mammalian cells, are sensitive to the microgravity environment, suggesting gravity affects fundamental cellular processes. However, performing well-controlled experiments aboard spacecraft offers unique challenges to the cell biologist. Although systems such as the European 'Biorack' provide generic experiment facilities including an incubator, on-board 1-g reference centrifuge, and contained area for manipulations, the experimenter must still establish a system for performing cell culture experiments that is compatible with the constraints of spaceflight. Two different cell culture kits developed by the French Space Agency, CNES, were recently used to perform a series of experiments during four flights of the 'Biorack' facility aboard the Space Shuttle. The first unit, Generic Cell Activation Kit 1 (GCAK-1), contains six separate culture units per cassette, each consisting of a culture chamber, activator chamber, filtration system (permitting separation of cells from supernatant in-flight), injection port, and supernatant collection chamber. The second unit (GCAK-2) also contains six separate culture units, including a culture, activator, and fixation chambers. Both hardware units permit relatively complex cell culture manipulations without extensive use of spacecraft resources (crew time, volume, mass, power), or the need for excessive safety measures. Possible operations include stimulation of cultures with activators, separation of cells from supernatant, fixation/lysis, manipulation of radiolabelled reagents, and medium exchange. Investigations performed aboard the Space Shuttle in six different experiments used Jurkat, purified T-cells or U937 cells, the results of which are reported separately. We report here the behaviour of Jurkat and U937 cells in the GCAK hardware in ground-based investigations simulating the conditions expected in the flight experiment. Several parameters including cell concentration, time between cell loading and activation, and storage temperature on cell survival were examined to characterise cell response and optimise the experiments to be flown aboard the Space Shuttle. Results indicate that the objectives of the experiments could be met with delays up to 5 days between cell loading into the hardware and initial in flight experiment activation, without the need for medium exchange. Experiment hardware of this kind, which is adaptable to a wide range of cell types and can be easily interfaced to different spacecraft facilities, offers the possibility for a wide range of experimenters successfully and easily to utilise future flight opportunities.

Autotransporter-based cell surface display in Gram-negative bacteria.

PubMed

Nicolay, Toon; Vanderleyden, Jos; Spaepen, Stijn

2015-02-01

Cell surface display of proteins can be used for several biotechnological applications such as the screening of protein libraries, whole cell biocatalysis and live vaccine development. Amongst all secretion systems and surface appendages of Gram-negative bacteria, the autotransporter secretion pathway holds great potential for surface display because of its modular structure and apparent simplicity. Autotransporters are polypeptides made up of an N-terminal signal peptide, a secreted or surface-displayed passenger domain and a membrane-anchored C-terminal translocation unit. Genetic replacement of the passenger domain allows for the surface display of heterologous passengers. An autotransporter-based surface expression module essentially consists of an application-dependent promoter system, a signal peptide, a passenger domain of interest and the autotransporter translocation unit. The passenger domain needs to be compatible with surface translocation although till now no general rules have been determined to test this compatibility. The autotransporter technology for surface display of heterologous passenger domains is critically discussed for various applications.

Research opportunities in loss of red blood cell mass in space flight

NASA Technical Reports Server (NTRS)

Talbot, J. M.; Fisher, K. D.

1985-01-01

Decreases of red blood cell mass and plasma volume have been observed consistently following manned space flights. Losses of red cell mass by United States astronauts have averaged 10 to 15% (range: 2 to 21%). Based on postflight estimates of total hemoglobin, Soviet cosmonauts engaged in space missions lasting from 1 to 7 months have exhibited somewhat greater losses. Restoration of red cell mass requires from 4 to 6 weeks following return to Earth, regardless of the duration of space flight.

Action Potential Waveform Variability Limits Multi-Unit Separation in Freely Behaving Rats

PubMed Central

Stratton, Peter; Cheung, Allen; Wiles, Janet; Kiyatkin, Eugene; Sah, Pankaj; Windels, François

2012-01-01

Extracellular multi-unit recording is a widely used technique to study spontaneous and evoked neuronal activity in awake behaving animals. These recordings are done using either single-wire or mulitwire electrodes such as tetrodes. In this study we have tested the ability of single-wire electrodes to discriminate activity from multiple neurons under conditions of varying noise and neuronal cell density. Using extracellular single-unit recording, coupled with iontophoresis to drive cell activity across a wide dynamic range, we studied spike waveform variability, and explored systematic differences in single-unit spike waveform within and between brain regions as well as the influence of signal-to-noise ratio (SNR) on the similarity of spike waveforms. We also modelled spike misclassification for a range of cell densities based on neuronal recordings obtained at different SNRs. Modelling predictions were confirmed by classifying spike waveforms from multiple cells with various SNRs using a leading commercial spike-sorting system. Our results show that for single-wire recordings, multiple units can only be reliably distinguished under conditions of high recording SNR (≥4) and low neuronal density (≈20,000/ mm3). Physiological and behavioural changes, as well as technical limitations typical of awake animal preparations, reduce the accuracy of single-channel spike classification, resulting in serious classification errors. For SNR <4, the probability of misclassifying spikes approaches 100% in many cases. Our results suggest that in studies where the SNR is low or neuronal density is high, separation of distinct units needs to be evaluated with great caution. PMID:22719894

Mouse mammary tumor virus-based vector transduces non-dividing cells, enters the nucleus via a TNPO3-independent pathway and integrates in a less biased fashion than other retroviruses.

PubMed

Konstantoulas, Constantine James; Indik, Stanislav

2014-04-30

Mouse mammary tumor virus (MMTV) is a complex, milk-born betaretrovirus, which preferentially infects dendritic cells (DC) in the gastrointestinal tract and then spreads to T and B lymphocytes and finally to the mammary gland. It is not clear how the prototypic betaretrovirus infects mucosal DCs and naïve lymphocytes as these cells are considered to be non-proliferative. Studies of MMTV biology have been hampered by the difficulty of obtaining sufficient virus/vector titers after transfection of a molecular clone in cultured cells. To surmount this barrier we developed a novel MMTV-based vector system with a split genome design containing potent posttranscriptional regulatory functions. Using this system, vector particles were produced to markedly greater titers (>1000-fold) than those obtained previously. The titers (>106 transduction units /ml) were comparable to those achieved with lentiviral or gammaretroviral vectors. Importantly, the vector transduced the enhanced green fluorescence protein gene into the chromosomes of non-dividing cells, such as cells arrested at the G2/M phase of the cell cycle and unstimulated hematopoietic progenitor cells, at an efficiency similar to that obtained with the HIV-1-based vector. In contrast to HIV-1, MMTV transductions were not affected by knocking down the expression of a factor involved in nuclear import of the HIV-1 pre-integration complexes, TNPO3. In contrast to HIV-1, the MMTV-based vector did not preferentially integrate in transcription units. Additionally, no preference for integration near transcription start sites, the regions preferentially targeted by gammaretroviral vectors, was observed. The vector derived from MMTV exhibits a random integration pattern. Overall, the betaretroviral vector system should facilitate molecular virology studies of the prototypic betaretrovirus as well as studies attempting to elucidate fundamental cellular processes such as nuclear import pathways. Random integration in cycling and non-cycling cells may be applicable in unbiased gene delivery.

Experimental muscle pain produces central modulation of proprioceptive signals arising from jaw muscle spindles.

PubMed

Capra, N F; Ro, J Y

2000-05-01

The aim of the present study was to investigate the effects of intramuscular injection with hypertonic saline, a well-established experimental model for muscle pain, on central processing of proprioceptive input from jaw muscle spindle afferents. Fifty-seven cells were recorded from the medial edge of the subnucleus interpolaris (Vi) and the adjacent parvicellular reticular formation from 11 adult cats. These cells were characterized as central units receiving jaw muscle spindle input based on their responses to electrical stimulation of the masseter nerve, muscle palpation and jaw stretch. Forty-five cells, which were successfully tested with 5% hypertonic saline, were categorized as either dynamic-static (DS) (n=25) or static (S) (n=20) neurons based on their responses to different speeds and amplitudes of jaw movement. Seventy-six percent of the cells tested with an ipsilateral injection of hypertonic saline showed a significant modulation of mean firing rates (MFRs) during opening and/or holding phases. The most remarkable saline-induced change was a significant reduction of MFR during the hold phase in S units (100%, 18/18 modulated). Sixty-nine percent of the DS units (11/16 modulated) also showed significant changes in MFRs limited to the hold phase. However, in the DS neurons, the MFRs increased in seven units and decreased in four units. Finally, five DS neurons showed significant changes of MFRs during both opening and holding phases. Injections of isotonic saline into the ipsilateral masseter muscle had little effect, but hypertonic saline injections made into the contralateral masseter muscle produced similar results to ipsilateral injections with hypertonic saline. These results unequivocally demonstrate that intramuscular injection with an algesic substance, sufficient to produce muscle pain, produces significant changes in the proprioceptive properties of the jaw movement-related neurons. Potential mechanisms involved in saline-induced changes in the proprioceptive signals and functional implications of the changes are discussed.

Relation Between the Cell Volume and the Cell Cycle Dynamics in Mammalian cell

NASA Astrophysics Data System (ADS)

Magno, A. C. G.; Oliveira, I. L.; Hauck, J. V. S.

2016-08-01

The main goal of this work is to add and analyze an equation that represents the volume in a dynamical model of the mammalian cell cycle proposed by Gérard and Goldbeter (2011) [1]. The cell division occurs when the cyclinB/Cdkl complex is totally degraded (Tyson and Novak, 2011)[2] and it reaches a minimum value. At this point, the cell is divided into two newborn daughter cells and each one will contain the half of the cytoplasmic content of the mother cell. The equations of our base model are only valid if the cell volume, where the reactions occur, is constant. Whether the cell volume is not constant, that is, the rate of change of its volume with respect to time is explicitly taken into account in the mathematical model, then the equations of the original model are no longer valid. Therefore, every equations were modified from the mass conservation principle for considering a volume that changes with time. Through this approach, the cell volume affects all model variables. Two different dynamic simulation methods were accomplished: deterministic and stochastic. In the stochastic simulation, the volume affects every model's parameters which have molar unit, whereas in the deterministic one, it is incorporated into the differential equations. In deterministic simulation, the biochemical species may be in concentration units, while in stochastic simulation such species must be converted to number of molecules which are directly proportional to the cell volume. In an effort to understand the influence of the new equation a stability analysis was performed. This elucidates how the growth factor impacts the stability of the model's limit cycles. In conclusion, a more precise model, in comparison to the base model, was created for the cell cycle as it now takes into consideration the cell volume variation

Stem Cell Niche is Partially Lost during Follicular Plucking: A Preliminary Pilot Study

PubMed Central

Kumar, Anil; Gupta, Somesh; Mohanty, Sujata; Bhargava, Balram; Airan, Balram

2013-01-01

Background: Clinical hair transplant studies have revealed that follicular unit extraction (FUE) is superior in terms of stable hair growth in comparison to follicular plucking (FP). Various reasons have been cited for this clinical outcome. FUE and FP are employed to obtain the hair follicle units for hair transplant and recently for cell based therapies in vitiligo. However, there is no scientific data available on the comparison of stem cell fraction in the cell suspension obtained by FUE and FP. Therefore, we undertook this study to compare the percentage of stem cells in the hair follicle obtained by FUE and FP. Objective: The purpose of the following study is to evaluate the quantitative stem cell pool in the hair follicle obtained by FUE and FP. Materials and Methods: A total of 3 human subjects were enrolled with age groups of 17-25 years. Both methods of tissue harvest: FUE and FP; were employed on each subject. There was no vitiligo lesion on the scalp in any of the patients. Hair follicles were incubated with trypsin-EDTA solution at 37°C for 90 min to separate outer root sheath cells. The cell suspension was passed through a 70 μm cell strainer; filtrate was centrifuged to obtain the cell pellet. Cells were labeled with cluster of differentiation (CD200) antibody and acquired with flowcytometry. Results: The mean percentage of CD200 positive cells in FUE and FP method come out to be 8.43 and 1.63 respectively (P = 0.0152). Conclusion: FUE is a better method of the hair follicle harvesting for cell based applications as the stem cell fraction is significantly higher in comparison to FP. PMID:24403776

High-Throughput Lectin Microarray-Based Analysis of Live Cell Surface Glycosylation

PubMed Central

Li, Yu; Tao, Sheng-ce; Zhu, Heng; Schneck, Jonathan P.

2011-01-01

Lectins, plant-derived glycan-binding proteins, have long been used to detect glycans on cell surfaces. However, the techniques used to characterize serum or cells have largely been limited to mass spectrometry, blots, flow cytometry, and immunohistochemistry. While these lectin-based approaches are well established and they can discriminate a limited number of sugar isomers by concurrently using a limited number of lectins, they are not amenable for adaptation to a high-throughput platform. Fortunately, given the commercial availability of lectins with a variety of glycan specificities, lectins can be printed on a glass substrate in a microarray format to profile accessible cell-surface glycans. This method is an inviting alternative for analysis of a broad range of glycans in a high-throughput fashion and has been demonstrated to be a feasible method of identifying binding-accessible cell surface glycosylation on living cells. The current unit presents a lectin-based microarray approach for analyzing cell surface glycosylation in a high-throughput fashion. PMID:21400689

Density Functional Study on A-Units Based on Thieno[3,4- c]pyrrole-4,6-dione for Organic Solar Cells

NASA Astrophysics Data System (ADS)

Tang, Xiaoqin; Shen, Wei; Fu, Zhiyong; Liu, Xiaorui; Li, Ming

2017-08-01

The use of polymer donor materials has allowed great progress in organic solar cells. To search for potential donor materials, we have designed a series of donor-acceptor (D-A)-type alternating polymers composed of dithieno[3,2- b:2',3'- d]pyrrole (DTP) electron-rich units and thieno[3,4- c]pyrrole-4,6-dione (TPD) electron-deficient units. Their electronic and optical properties have been investigated using density functional theory and Marcus theory. The calculation results demonstrate that introduction of cyclic compounds (furyl, thienyl, and phenyl) into electron-deficient units of the molecules can result in lower highest occupied molecular orbital (HOMO) levels and reorganization energies compared with the experimental molecule ( X 0 ). To investigate the effects of electron-withdrawing units, three electron-withdrawing substituents (-OCH3, -F, and -CN) were introduced into the thienyl. The results indicated that the polymer X 2-3 will show the best performance among the designed polymers, offering low-lying HOMO energy level (-5.47 eV), narrow energy gap (1.97 eV), and high hole mobility (7.45 × 10-2 cm2 V-1 s-1). This work may provide a guideline for the design of efficient D-A polymers for organic solar cells with enhanced performance.

Evaluation of the impact of banking umbilical cord blood units with high cell dose for ethnically diverse patients.

PubMed

Stritesky, Gretta; Wadsworth, Kimberly; Duffy, Merry; Buck, Kelly; Dehn, Jason

2018-02-01

Umbilical cord blood units provide an important stem cell source for transplantation, particularly for patients of ethnic diversity who may not have suitably matched available, adult-unrelated donors. However, with the cost of cord blood unit acquisition from public banks significantly higher than that for adult-unrelated donors, attention is focused on decreasing cost yet still providing cord blood units to patients in need. Historical practices of banking units with low total nucleated cell counts, including units with approximately 90 × 10 7 total nucleated cells, indicates that most banked cord blood units have much lower total nucleated cell counts than are required for transplant. The objective of this study was to determine the impact on the ability to identify suitable cord blood units for transplantation if the minimum total nucleated cell count for banking were increased from 90 × 10 7 to 124 or 149 × 10 7 . We analyzed ethnically diverse patients (median age, 3 years) who underwent transplantation of a single cord blood unit in 2005 to 2016. A cord blood unit search was evaluated to identify units with equal or greater human leukocyte antigen matching and a greater total nucleated cell count than that of the transplanted cord blood unit (the replacement cord blood unit). If the minimum total nucleated cell count for banking increased to 124 or 149 × 10 7 , then from 75 to 80% of patients would still have at least 1 replacement cord blood unit in the current (2016) cord blood unit inventory. The best replacement cord blood units were often found among cords with the same ethnic background as the patient. The current data suggest that, if the minimum total nucleated cell count were increased for banking, then it would likely lead to an inventory of more desirable cord blood units while having minimal impact on the identification of suitable cord blood units for transplantation. © 2017 AABB.

Optimal Design of Miniaturized Reflecting Metasurfaces for Ultra-Wideband and Angularly Stable Polarization Conversion.

PubMed

Borgese, Michele; Costa, Filippo; Genovesi, Simone; Monorchio, Agostino; Manara, Giuliano

2018-05-16

An ultra-wideband linear polarization converter based on a reflecting metasurface is presented. The polarizer is composed by a periodic arrangement of miniaturized metallic elements printed on a grounded dielectric substrate. In order to achieve broadband polarization converting properties, the metasurface is optimized by employing a genetic algorithm (GA) which imposes the minimization of the amplitude of the co-polar reflection coefficient over a wide frequency band. The enhanced angular stability of the polarization converter is due to the miniaturized unit cell which is obtained by imposing the maximum periodicity of the metasurface in the GA optimization process. The pixelated polarization converter obtained by the GA exhibits a relative bandwidth of 102% working from 8.12 GHz to 25.16 GHz. The analysis of the surface current distribution of the metasurface led to a methodology for refining the optimized GA solution based on the sequential removal of pixels of the unit cell on which surface currents are not excited. The relative bandwidth of the refined polarizer is extended up to 117.8% with a unit cell periodicity of 0.46 mm, corresponding to λ/20 at the maximum operating frequency. The performance of the proposed ultra-wideband polarization metasurface has been confirmed through full-wave simulations and measurements.

Fusing Benzo[c][1,2,5]oxadiazole Unit with Thiophene for Constructing Wide-bandgap High-performance IDT-based Polymer Solar Cell Donor Material.

PubMed

Song, Xin; Fan, Meijie; Zhang, Kaili; Ding, Dakang; Chen, Weiye; Li, Yonghai; Yu, Liangmin; Sun, Mingliang; Yang, Renqiang

2018-04-01

Benzo[c][1,2,5]oxadiazole (BO) moiety is a strong electron-withdrawing unit compared to benzo[c][1,2,5]thiadiazole (BT). It is usually introduced as an acceptor to construct narrow band-gap donor-acceptor (D-A) materials. Herein, the π-extended conjugated moiety dithieno[3',2':3,4″;2,3″:5,6]benzo[1,2-c][1,2,5]oxadiazole (BOT) was adopted as the acceptor moiety to design D-A polymers. Considering the more extended π-conjugated molecular system of BOT compared to the BO unit, a narrower optical band-gap is expected for BOT-based IDT polymer (PIDT-BOT). Unexpectedly, the UV-vis absorption spectra of PIDT-BOT films display a great hypochromatic shift of about 60 nm compared to a BO-based analog (PIDT-BO). The optical band-gaps of the materials are broadened from 1.63 eV (PIDT-BO) to 2.00 eV (PIDT-BOT) accordingly. Although the range of external quantum efficiency (EQE) of PIDT-BOT-based polymer solar cell (PSC) devices is not as wide as for PIDT-BO-based devices, the EQE response intensities of the PIDT-BOT based device are evidently high. As a result, PSC devices based on PIDT-BOT reveal the best power conversion efficiency at 6.08%. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supporting High School Student Accomplishment of Biology Content Using Interactive Computer-Based Curricular Case Studies

NASA Astrophysics Data System (ADS)

Oliver, Joseph Steve; Hodges, Georgia W.; Moore, James N.; Cohen, Allan; Jang, Yoonsun; Brown, Scott A.; Kwon, Kyung A.; Jeong, Sophia; Raven, Sara P.; Jurkiewicz, Melissa; Robertson, Tom P.

2017-11-01

Research into the efficacy of modules featuring dynamic visualizations, case studies, and interactive learning environments is reported here. This quasi-experimental 2-year study examined the implementation of three interactive computer-based instructional modules within a curricular unit covering cellular biology concepts in an introductory high school biology course. The modules featured dynamic visualizations and focused on three processes that underlie much of cellular biology: diffusion, osmosis, and filtration. Pre-tests and post-tests were used to assess knowledge growth across the unit. A mixture Rasch model analysis of the post-test data revealed two groups of students. In both years of the study, a large proportion of the students were classified as low-achieving based on their pre-test scores. The use of the modules in the Cell Unit in year 2 was associated with a much larger proportion of the students having transitioned to the high-achieving group than in year 1. In year 2, the same teachers taught the same concepts as year 1 but incorporated the interactive computer-based modules into the cell biology unit of the curriculum. In year 2, 67% of students initially classified as low-achieving were classified as high-achieving at the end of the unit. Examination of responses to assessments embedded within the modules as well as post-test items linked transition to the high-achieving group with correct responses to items that both referenced the visualization and the contextualization of that visualization within the module. This study points to the importance of dynamic visualization within contextualized case studies as a means to support student knowledge acquisition in biology.

Towards predictive molecular dynamics simulations of DNA: electrostatics and solution/crystal environments

NASA Astrophysics Data System (ADS)

Babin, Volodymr; Baucom, Jason; Darden, Thomas; Sagui, Celeste

2006-03-01

We have investigated to what extend molecular dynamics (MD) simulatons can reproduce DNA sequence-specific features, given different electrostatic descriptions and different cell environments. For this purpose, we have carried out multiple unrestrained MD simulations of the duplex d(CCAACGTTGG)2. With respect to the electrostatic descriptions, two different force fields were studied: a traditional description based on atomic point charges and a polarizable force field. With respect to the cell environment, the difference between crystal and solution environments is emphasized, as well as the structural importance of divalent ions. By imposing the correct experimental unit cell environment, an initial configuration with two ideal B-DNA duplexes in the unit cell is shown to converge to the crystallographic structure. To the best of our knowledge, this provides the first example of a multiple nanosecond MD trajectory that shows and ideal structure converging to an experimental one, with a significant decay of the RMSD.

3D braid scaffolds for regeneration of articular cartilage.

PubMed

Ahn, Hyunchul; Kim, Kyoung Ju; Park, Sook Young; Huh, Jeong Eun; Kim, Hyun Jeong; Yu, Woong-Ryeol

2014-06-01

Regenerating articular cartilage in vivo from cultured chondrocytes requires that the cells be cultured and implanted within a biocompatible, biodegradable scaffold. Such scaffolds must be mechanically stable; otherwise chondrocytes would not be supported and patients would experience severe pain. Here we report a new 3D braid scaffold that matches the anisotropic (gradient) mechanical properties of natural articular cartilage and is permissive to cell cultivation. To design an optimal structure, the scaffold unit cell was mathematically modeled and imported into finite element analysis. Based on this analysis, a 3D braid structure with gradient axial yarn distribution was designed and manufactured using a custom-built braiding machine. The mechanical properties of the 3D braid scaffold were evaluated and compared with simulated results, demonstrating that a multi-scale approach consisting of unit cell modeling and continuum analysis facilitates design of scaffolds that meet the requirements for mechanical compatibility with tissues. Copyright © 2014 Elsevier Ltd. All rights reserved.

A wave-bending structure at Ka-band using 3D-printed metamaterial

NASA Astrophysics Data System (ADS)

Wu, Junqiang; Liang, Min; Xin, Hao

2018-03-01

Three-dimensional printing technologies enable metamaterials of complex structures with arbitrary inhomogeneity. In this work, a 90° wave-bending structure at the Ka-band (26.5-40 GHz) based on 3D-printed metamaterials is designed, fabricated, and measured. The wave-bending effect is realized through a spatial distribution of varied effective dielectric constants. Based on the effective medium theory, different effective dielectric constants are accomplished by special, 3D-printable unit cells, which allow different ratios of dielectric to air at the unit cell level. In contrast to traditional, metallic-structure-included metamaterial designs, the reported wave-bending structure here is all dielectric and implemented by the polymer-jetting technique, which features rapid, low-cost, and convenient prototyping. Both simulation and experiment results demonstrate the effectiveness of the wave-bending structure.

Unusually large unit cell of lipid bicontinuous cubic phase: towards nature's length scales

NASA Astrophysics Data System (ADS)

Kim, Hojun; Leal, Cecilia

Lipid bicontinuous cubic phases are of great interest for drug delivery, protein crystallization, biosensing, and templates for directing hard material assembly. Structural modulations of lipid mesophases regarding phase identity and unit cell size are often necessary to augment loading and gain pore size control. One important example is the need for unit cells large enough to guide the crystallization of bigger proteins without distortion of the templating phase. In nature, bicontinuous cubic constructs achieve unit cell dimensions as high as 300 nm. However, the largest unit cell of lipid mesophases synthesized in the lab is an order of magnitude lower. In fact, it has been predicted theoretically that lipid bicontinuous cubic phases of unit cell dimensions exceeding 30 nm could not exist, as high membrane fluctuations would damp liquid crystalline order. Here we report non-equilibrium assembly methods of synthesizing metastable bicontinuous cubic phases with unit cell dimensions as high as 70 nm. The phases are stable for very long periods and become increasingly ordered as time goes by without changes to unit cell dimensions. We acknowledge the funding source as a NIH.

Diagnosable structured logic array

NASA Technical Reports Server (NTRS)

Whitaker, Sterling (Inventor); Miles, Lowell (Inventor); Gambles, Jody (Inventor); Maki, Gary K. (Inventor)

2009-01-01

A diagnosable structured logic array and associated process is provided. A base cell structure is provided comprising a logic unit comprising a plurality of input nodes, a plurality of selection nodes, and an output node, a plurality of switches coupled to the selection nodes, where the switches comprises a plurality of input lines, a selection line and an output line, a memory cell coupled to the output node, and a test address bus and a program control bus coupled to the plurality of input lines and the selection line of the plurality of switches. A state on each of the plurality of input nodes is verifiably loaded and read from the memory cell. A trusted memory block is provided. The associated process is provided for testing and verifying a plurality of truth table inputs of the logic unit.

Silicon wafer-based tandem cells: The ultimate photovoltaic solution?

NASA Astrophysics Data System (ADS)

Green, Martin A.

2014-03-01

Recent large price reductions with wafer-based cells have increased the difficulty of dislodging silicon solar cell technology from its dominant market position. With market leaders expected to be manufacturing modules above 16% efficiency at 0.36/Watt by 2017, even the cost per unit area (60-70/m2) will be difficult for any thin-film photovoltaic technology to significantly undercut. This may make dislodgement likely only by appreciably higher energy conversion efficiency approaches. A silicon wafer-based cell able to capitalize on on-going cost reductions within the mainstream industry, but with an appreciably higher than present efficiency, might therefore provide the ultimate PV solution. With average selling prices of 156 mm quasi-square monocrystalline Si photovoltaic wafers recently approaching 1 (per wafer), wafers now provide clean, low cost templates for overgrowth of thin, wider bandgap high performance cells, nearly doubling silicon's ultimate efficiency potential. The range of possible Si-based tandem approaches is reviewed together with recent results and ultimate prospects.

Radar cross-section reduction based on an iterative fast Fourier transform optimized metasurface

NASA Astrophysics Data System (ADS)

Song, Yi-Chuan; Ding, Jun; Guo, Chen-Jiang; Ren, Yu-Hui; Zhang, Jia-Kai

2016-07-01

A novel polarization insensitive metasurface with over 25 dB monostatic radar cross-section (RCS) reduction is introduced. The proposed metasurface is comprised of carefully arranged unit cells with spatially varied dimension, which enables approximate uniform diffusion of incoming electromagnetic (EM) energy and reduces the threat from bistatic radar system. An iterative fast Fourier transform (FFT) method for conventional antenna array pattern synthesis is innovatively applied to find the best unit cell geometry parameter arrangement. Finally, a metasurface sample is fabricated and tested to validate RCS reduction behavior predicted by full wave simulation software Ansys HFSSTM and marvelous agreement is observed.

Advances in clinical NK cell studies: Donor selection, manufacturing and quality control

PubMed Central

Koehl, U.; Kalberer, C.; Spanholtz, J.; Lee, D. A.; Miller, J. S.; Cooley, S.; Lowdell, M.; Uharek, L.; Klingemann, H.; Curti, A.; Leung, W.; Alici, E.

2016-01-01

ABSTRACT Natural killer (NK) cells are increasingly used in clinical studies in order to treat patients with various malignancies. The following review summarizes platform lectures and 2013–2015 consortium meetings on manufacturing and clinical use of NK cells in Europe and United States. A broad overview of recent pre-clinical and clinical results in NK cell therapies is provided based on unstimulated, cytokine-activated, as well as genetically engineered NK cells using chimeric antigen receptors (CAR). Differences in donor selection, manufacturing and quality control of NK cells for cancer immunotherapies are described and basic recommendations are outlined for harmonization in future NK cell studies. PMID:27141397

Cell phone recycling experiences in the United States and potential recycling options in Brazil.

PubMed

Silveira, Geraldo T R; Chang, Shoou-Yuh

2010-11-01

This paper presents an overview of cell phone recycling programs currently available in the United States. At the same time, it also provides analyses of the current recycling situation and possible recycling alternatives for Brazil. Although there are several recycling options in the United States, collection rates are still only 10% of all potential devices because customers are not aware of these possibilities. The whole system is financially based on reselling refurbished cell phones and recycled materials to developing countries which represent an effective and strong market. Several recyclers offer funds to collection partners who are either charities or who work with charities while obtaining the materials that they need in order to run their operations. A mobile phone recycling system for Brazil considering the United States experience and the Extended Producer Responsibility (EPR) principle is suggested. A deposit/refund/advance-recycling fee is proposed which might be implemented as a voluntary industrial initiative managed by PRO Brazil, a producer responsibility organization. One widespread public-private agreement will integrate all mobile phone stakeholders, and environmental education actions and promotional events will promote citizen's participation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Formation of rarefaction waves in origami-based metamaterials

NASA Astrophysics Data System (ADS)

Yasuda, H.; Chong, C.; Charalampidis, E. G.; Kevrekidis, P. G.; Yang, J.

2016-04-01

We investigate the nonlinear wave dynamics of origami-based metamaterials composed of Tachi-Miura polyhedron (TMP) unit cells. These cells exhibit strain softening behavior under compression, which can be tuned by modifying their geometrical configurations or initial folded conditions. We assemble these TMP cells into a cluster of origami-based metamaterials, and we theoretically model and numerically analyze their wave transmission mechanism under external impact. Numerical simulations show that origami-based metamaterials can provide a prototypical platform for the formation of nonlinear coherent structures in the form of rarefaction waves, which feature a tensile wavefront upon the application of compression to the system. We also demonstrate the existence of numerically exact traveling rarefaction waves in an effective lumped-mass model. Origami-based metamaterials can be highly useful for mitigating shock waves, potentially enabling a wide variety of engineering applications.

High collimated coherent illumination for reconstruction of digitally calculated holograms: design and experimental realization

NASA Astrophysics Data System (ADS)

Morozov, Alexander; Dubinin, German; Dubynin, Sergey; Yanusik, Igor; Kim, Sun Il; Choi, Chil-Sung; Song, Hoon; Lee, Hong-Seok; Putilin, Andrey; Kopenkin, Sergey; Borodin, Yuriy

2017-06-01

Future commercialization of glasses-free holographic real 3D displays requires not only appropriate image quality but also slim design of backlight unit and whole display device to match market needs. While a lot of research aimed to solve computational issues of forming Computer Generated Holograms for 3D Holographic displays, less focus on development of backlight units suitable for 3D holographic display applications with form-factor of conventional 2D display systems. Thereby, we report coherent backlight unit for 3D holographic display with thickness comparable to commercially available 2D displays (cell phones, tablets, laptops, etc.). Coherent backlight unit forms uniform, high-collimated and effective illumination of spatial light modulator. Realization of such backlight unit is possible due to holographic optical elements, based on volume gratings, constructing coherent collimated beam to illuminate display plane. Design, recording and measurement of 5.5 inch coherent backlight unit based on two holographic optical elements are presented in this paper.

Modulation of π-spacer of carbazole-carbazole based organic dyes toward high efficient dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Chitpakdee, Chirawat; Jungsuttiwong, Siriporn; Sudyoadsuk, Taweesak; Promarak, Vinich; Kungwan, Nawee; Namuangruk, Supawadee

2017-03-01

The effects of type and position of π-linker in carbazole-carbazole based dyes on their performance in dye-sensitized solar cells (DSSCs) were investigated by DFT and TDDFT methods. The calculated electronic energy level, electron density composition, charge injection and charge recombination properties were compared with those of the high performance CCT3A dye synthesized recently. It is found that that mixing a benzothiadizole (B) unit with two thiophene (T) units in the π-spacer can greatly shift absorption wavelength to near infrared region and enhance the light harvesting efficiency (LHE) resulting in increasing of short-circuit current density (Jsc), whereas a thienothiophene unit does not affect those properties. However, a B should be not directly connected to the anchoring group of the dye because it brings electrolyte to the TiO2 surface which may increase charge recombination rate and consequently decrease open circuit voltage (Voc). This work shows how type and position of the π-linker affect the performance of DSSCs, and how to modulate those properties. We predicted that the designed dye derived from insertion of the B unit in between the two T units would have higher performance than CCT3A dye. The insight understanding from this study is useful for further design of higher performance dyes by molecular engineering.

Continuous pH monitoring in a perfused bioreactor system using an optical pH sensor

NASA Technical Reports Server (NTRS)

Jeevarajan, Antony S.; Vani, Sundeep; Taylor, Thomas D.; Anderson, Melody M.

2002-01-01

Monitoring and regulating the pH of the solution in a bioprocess is one of the key steps in the success of bioreactor operation. An in-line optical pH sensor, based on the optical absorption properties of phenol red present in the medium, was developed and tested in this work for use in NASA space bioreactors based on a rotating wall-perfused vessel system supporting a baby hamster kidney (BHK-21) cell culture. The sensor was tested over three 30-day and one 124-day cell runs. The pH sensor initially was calibrated and then used during the entire cell culture interval. The pH reported by the sensor was compared to that measured by a fiber optically coupled Shimadzu spectrophotometer and a blood gas analyzer. The maximum standard error of prediction for all the four cell runs for development pH sensor against BGA was +/-0.06 pH unit and for the fiber optically coupled Shimadzu spectrophotometer against the blood gas analyzer was +/-0.05 pH unit. The pH sensor system performed well without need of recalibration for 124 days. Copyright 2002 Wiley Periodicals, Inc.

High-Performance All-Polymer Solar Cells Achieved by Fused Perylenediimide-Based Conjugated Polymer Acceptors.

PubMed

Yin, Yuli; Yang, Jing; Guo, Fengyun; Zhou, Erjun; Zhao, Liancheng; Zhang, Yong

2018-05-09

We report three n-type polymeric electron acceptors (PFPDI-TT, PFPDI-T, and PFPDI-Se) based on the fused perylene diimide (FPDI) and thieno[3,2- b]thiophene, thiophene, or selenophene units for all-polymer solar cells (all-PSCs). These FPDI-based polymer acceptors exhibit strong absorption between 350 and 650 nm with wide optical bandgap of 1.86-1.91 eV, showing good absorption compensation with the narrow bandgap polymer donor. The lowest unoccupied molecular orbital (LUMO) energy levels were located at around -4.11 eV, which are comparable with those of the fullerene derivatives and other small molecular electron acceptors. The conventional all-PSCs based on the three polymer acceptors and PTB7-Th as polymer donor gave remarkable power conversion efficiencies (PCEs) of >6%, and the PFPDI-Se-based all-PSC achieved the highest PCE of 6.58% with a short-circuit current density ( J sc ) of 13.96 mA/cm 2 , an open-circuit voltage ( V oc ) of 0.76 V, and a fill factor (FF) of 62.0%. More interestingly, our results indicate that the photovoltaic performances of the FPDI-based polymer acceptors are mainly determined by the FPDI unit with a small effect from the comonomers, which is quite different from the others reported rylenediimide-based polymer acceptors. This intriguing phenomenon is speculated as the huge geometry configuration of the FPDI unit, which minimizes the effect of the comonomer. These results highlight a promising future for the application of the FPDI-based polymer acceptors in the highly efficient all-PSCs.

A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications.

PubMed

Islam, Md Moinul; Islam, Mohammad Tariqul; Samsuzzaman, Md; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah; Mansor, Mohd Fais

2015-01-23

A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm³, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4-12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.

Thermal expansion of coesite determined by synchrotron powder X-ray diffraction

NASA Astrophysics Data System (ADS)

Kulik, Eleonora; Murzin, Vadim; Kawaguchi, Shogo; Nishiyama, Norimasa; Katsura, Tomoo

2018-05-01

Thermal expansion of synthetic coesite was studied with synchrotron powder X-ray diffraction in the temperature range of 100-1000 K. We determined the unit cell parameters of monoclinic coesite (a, b, c, and β) every 50 K in this temperature range. We observed that a and b parameters increase with increasing temperature, while c decreases. The β angle also decreases with temperature and approaches 120°. As a result, the unit cell volume expands by only 0.7% in this temperature range. Our measurements provide thermal expansion coefficients of coesite as a function of temperature: it increases from 3.4 × 10-6 K-1 at 100 K to 9.3 × 10-6 K-1 at 600 K and remains nearly constant above this temperature. The Suzuki model based on the zero-pressure Mie-Grüneisen equation of state was implemented to fit the unit cell volume data. The refined parameters are {V_0} = 546.30(2) Å3, Q = 7.20(12) × 106 J/mol and {θ D} = 1018(43) K, where {θ D} is the Debye temperature and {V_0} is the unit cell volume at 0 K with an assumption that {K^' } is equal to 1.8. The obtained Debye temperature is consistent with that determined in a previous study for heat capacity measurements.

Emerging Technologies for Assembly of Microscale Hydrogels

PubMed Central

Kavaz, Doga; Demirel, Melik C.; Demirci, Utkan

2013-01-01

Assembly of cell encapsulating building blocks (i.e., microscale hydrogels) has significant applications in areas including regenerative medicine, tissue engineering, and cell-based in vitro assays for pharmaceutical research and drug discovery. Inspired by the repeating functional units observed in native tissues and biological systems (e.g., the lobule in liver, the nephron in kidney), assembly technologies aim to generate complex tissue structures by organizing microscale building blocks. Novel assembly technologies enable fabrication of engineered tissue constructs with controlled properties including tunable microarchitectural and predefined compositional features. Recent advances in micro- and nano-scale technologies have enabled engineering of microgel based three dimensional (3D) constructs. There is a need for high-throughput and scalable methods to assemble microscale units with a complex 3D micro-architecture. Emerging assembly methods include novel technologies based on microfluidics, acoustic and magnetic fields, nanotextured surfaces, and surface tension. In this review, we survey emerging microscale hydrogel assembly methods offering rapid, scalable microgel assembly in 3D, and provide future perspectives and discuss potential applications. PMID:23184717

Annular feed air breathing fuel cell stack

DOEpatents

Wilson, Mahlon S.

1996-01-01

A stack of polymer electrolyte fuel cells is formed from a plurality of unit cells where each unit cell includes fuel cell components defining a periphery and distributed along a common axis, where the fuel cell components include a polymer electrolyte membrane, an anode and a cathode contacting opposite sides of the membrane, and fuel and oxygen flow fields contacting the anode and the cathode, respectively, wherein the components define an annular region therethrough along the axis. A fuel distribution manifold within the annular region is connected to deliver fuel to the fuel flow field in each of the unit cells. In a particular embodiment, a single bolt through the annular region clamps the unit cells together. In another embodiment, separator plates between individual unit cells have an extended radial dimension to function as cooling fins for maintaining the operating temperature of the fuel cell stack.

Solid oxide fuel cell with multi-unit construction and prismatic design

DOEpatents

McPheeters, Charles C.; Dees, Dennis W.; Myles, Kevin M.

1999-01-01

A single cell unit of a solid oxide fuel cell that is individually fabricated and sintered prior to being connected to adjacent cells to form a solid oxide fuel cell. The single cell unit is comprised of a shaped anode sheet positioned between a flat anode sheet and an anode-electrolyte-cathode (A/E/C) sheet, and a shaped cathode sheet positioned between the A/E/C sheet and a cathode-interconnect-anode (C/I/A) sheet. An alternate embodiment comprises a shaped cathode sheet positioned between an A/E/C sheet and a C/I/A sheet. The shaped sheets form channels for conducting reactant gases. Each single cell unit is individually sintered to form a finished sub-assembly. The finished sub-assemblies are connected in electrical series by interposing connective material between the end surfaces of adjacent cells, whereby individual cells may be inspected for defects and interchanged with non-defective single cell units.

Three dimensional metafilms with dual channel unit cells

DOE PAGES

Burckel, D. Bruce; Campione, Salvatore; Davids, Paul S.; ...

2017-04-04

Three-dimensional (3D) metafilms composed of periodic arrays of silicon unit cells containing single and multiple micrometer-scale vertical split ring resonators (SRRs) per unit cell were fabricated. In contrast to planar and stacked planar structures, these 3D metafilms have a thickness t ~λ d/4, allowing for classical thin film effects in the long wavelength limit. The infrared specular far-field scattering response was measured for metafilms containing one and two resonators per unit cell and compared to numerical simulations. Excellent agreement in the frequency region below the onset of diffractive scattering was obtained. For dense arrays of unit cells containing single SRRs,more » normally incident linearly polarized plane waves which do not excite a resonant response result in thin film interference fringes in the reflected spectra and are virtually indistinguishable from the scattering response of an undecorated array of unit cells. For the resonant linear polarization, the specular reflection for arrays is highly dependent on the SRR orientation on the vertical face for gap-up, gap-down, and gap-right orientations. For dense arrays of unit cells containing two SRRs per unit cell positioned on adjacent faces, the specular reflection spectra are slightly modified due to near-field coupling between the orthogonally oriented SRRs but otherwise exhibit reflection spectra largely representative of the corresponding single-SRR unit cell structures. Lastly, the ability to pack the unit cell with multiple inclusions which can be independently excited by choice of incident polarization suggests the construction of dual-channel films where the scattering response is selected by altering the incident polarization.« less

Lithium-Ion Cell Charge-Control Unit Developed

NASA Technical Reports Server (NTRS)

Reid, Concha M.; Manzo, Michelle A.; Buton, Robert M.; Gemeiner, Russel

2005-01-01

A lithium-ion (Li-ion) cell charge-control unit was developed as part of a Li-ion cell verification program. This unit manages the complex charging scheme that is required when Li-ion cells are charged in series. It enables researchers to test cells together as a pack, while allowing each cell to charge individually. This allows the inherent cell-to-cell variations to be addressed on a series string of cells and reduces test costs substantially in comparison to individual cell testing.

Transfer Function Bounds for Partial-unit-memory Convolutional Codes Based on Reduced State Diagram

NASA Technical Reports Server (NTRS)

Lee, P. J.

1984-01-01

The performance of a coding system consisting of a convolutional encoder and a Viterbi decoder is analytically found by the well-known transfer function bounding technique. For the partial-unit-memory byte-oriented convolutional encoder with m sub 0 binary memory cells and (k sub 0 m sub 0) inputs, a state diagram of 2(K) (sub 0) was for the transfer function bound. A reduced state diagram of (2 (m sub 0) +1) is used for easy evaluation of transfer function bounds for partial-unit-memory codes.

Microfabrication of proangiogenic cell-laden alginate-g-pyrrole hydrogels.

PubMed

DeVolder, Ross J; Zill, Andrew T; Jeong, Jae H; Kong, Hyunjoon

2012-11-01

Cells have been extensively studied for their uses in various therapies because of their capacities to produce therapeutic proteins and recreate new tissues. It has often been suggested that the efficacy of cell therapies can greatly be improved through the ability to localize and regulate cellular activities at a transplantation site; however, the technologies for this control are lacking. Therefore, this study reports a cell-Laden hydrogel patch engineered to support the proliferation and angiogenic growth factor expression of cells adhered to their surfaces, and to further promote neovascularization. Hydrogels consisting of alginate chemically linked with pyrrole units, termed alginate-g-pyrrole, were prepared through an oxidative cross-linking reaction between pyrrole units. Fibroblasts adhered to the alginate-g-pyrrole hydrogels, and exhibited increased proliferation and overall vascular endothelial growth factor (VEGF) expression, compared to those on pyrrole-free hydrogels. Furthermore, the alginate-g-pyrrole hydrogel surfaces were modified to present microposts, subsequently increasing the amount of pyrrole units on their surfaces. Cells adhered to the microfabricated gel surfaces exhibited increased proliferation and overall VEGF expression proportional to the density of the microposts. The resulting micropatterned alginate-g-pyrrole hydrogels exhibited increases in the size and density of mature blood vessels when implanted on chick chorioallantoic membranes (CAMs). The hydrogel system developed in this study will be broadly useful for improving the efficacy of a wide array of cell-based wound healing and tissue regenerative therapies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biophysically based mathematical modeling of interstitial cells of Cajal slow wave activity generated from a discrete unitary potential basis.

PubMed

Faville, R A; Pullan, A J; Sanders, K M; Koh, S D; Lloyd, C M; Smith, N P

2009-06-17

Spontaneously rhythmic pacemaker activity produced by interstitial cells of Cajal (ICC) is the result of the entrainment of unitary potential depolarizations generated at intracellular sites termed pacemaker units. In this study, we present a mathematical modeling framework that quantitatively represents the transmembrane ion flows and intracellular Ca2+ dynamics from a single ICC operating over the physiological membrane potential range. The mathematical model presented here extends our recently developed biophysically based pacemaker unit modeling framework by including mechanisms necessary for coordinating unitary potential events, such as a T-Type Ca2+ current, Vm-dependent K+ currents, and global Ca2+ diffusion. Model simulations produce spontaneously rhythmic slow wave depolarizations with an amplitude of 65 mV at a frequency of 17.4 cpm. Our model predicts that activity at the spatial scale of the pacemaker unit is fundamental for ICC slow wave generation, and Ca2+ influx from activation of the T-Type Ca2+ current is required for unitary potential entrainment. These results suggest that intracellular Ca2+ levels, particularly in the region local to the mitochondria and endoplasmic reticulum, significantly influence pacing frequency and synchronization of pacemaker unit discharge. Moreover, numerical investigations show that our ICC model is capable of qualitatively replicating a wide range of experimental observations.

Synthesis and characterization of donor-acceptor copolymers carrying triphenylamine units for photovoltaic applications

NASA Astrophysics Data System (ADS)

Neumann, Katharina; Thelakkat, Mukundan

2012-09-01

The synthesis and analysis of solution processable polymers for organic solar cells is crucial for innovative solar cell technologies such as printing processes. In the field of donor materials for photovoltaic applications, polymers based on tetraphenylamine (TPA) are well known hole conducting materials. Here, we synthesized two conjugated TPA containing copolymers via Suzuki polycondensation. We investigated the tuning of the energy levels of the TPA based polymers by two different concepts. Firstly, we introduced an acceptor unit in the side chain. The main-chain of this copolymer was built from TPA units. The resulting copolymer 2-(4-((4'-((4-(2-ethylhexyloxy)phenyl)(paratolyl) amino)biphenyl-4-yl)(para-tolyl)amino)benzylidene) malononitrile P1 showed a broader absorption up to 550 nm. Secondly, we used a donor-acceptor concept by synthesizing a copolymer with alternating electron donating TPA and electron withdrawing Thieno[3,4-b]thiophene ester units. Consequently, the absorption maximum in the copolymer octyl-6-(4-((4-(2-ethylhexyloxy)phenyl)(p-tolyl)amino)phenyl)-4-methylthieno[3,4-b]thiophene-2-carboxylate P2 was red shifted to 580 nm. All three polymers showed high thermal stability. By UV-vis and Cyclic voltammetry measurements the optical and electrochemical properties of the polymers were analyzed.

Approximate Boundaries for West Lake Landfill, Missouri, 2014, EPA REG 07

EPA Pesticide Factsheets

This ESRI File Geodatabase Feature Class contains polygons for GIS depicting the approximate boundaries for West Lake Landfill (MOD079900932), Missouri, 2014, EPA REG 07These polygons are for graphically representing the site. The estimated boundary was developed using St. Louis County Parcels (2014). The boundaries of the individual landfill cells and areas within the site are interpolated based on sample results from the Remedial Investigation Report, ??EMSI, 2000, Remedial Investigation Report, West Lake Landfill Operable Unit 1, April 10.??Boundaries for Operational Units derived from CAD drawings provided by Aquaterra Environmental Solutions, Inc based on work provided by Herst & Associates Inc. and published in the Record of Decision, West Lake Landfill Site, Bridgeton, Missouri, Operable Unit 2, July 2008. CERCLIS ID MOD079900932.

The Daniell cell, Ohm's law, and the emergence of the International System of Units

NASA Astrophysics Data System (ADS)

Jayson, Joel S.

2014-01-01

Telegraphy originated in the 1830s and 40 s and flourished in the following decades but with a patchwork of electrical standards. Electromotive force was for the most part measured in units of the predominant Daniell cell, but each telegraphy company had their own resistance standard. In 1862, the British Association for the Advancement of Science formed a committee to address this situation. By 1873, they had given definition to the electromagnetic system of units (emu) and defined the practical units of the ohm as 109 emu units of resistance and the volt as 108 emu units of electromotive force. These recommendations were ratified and expanded upon in a series of international congresses held between 1881 and 1904. A proposal by Giovanni Giorgi in 1901 took advantage of a coincidence between the conversion of the units of energy in the emu system (the erg) and in the practical system (the Joule). As it was, the same conversion factor existed between the cgs based emu system and a theretofore undefined MKS system. By introducing another unit X (where X could be any of the practical electrical units), Giorgi demonstrated that a self-consistent MKSX system was tenable without the need for multiplying factors. Ultimately, the ampere was selected as the fourth unit. It took nearly 60 years, but in 1960, Giorgi's proposal was incorporated as the core of the newly inaugurated International System of Units (SI). This article surveys the physics, physicists, and events that contributed to those developments.

A Micro Fluorescent Activated Cell Sorter for Astrobiology Applications

NASA Technical Reports Server (NTRS)

Platt, Donald W.; Hoover, Richard B.

2009-01-01

A micro-scale Fluorescent Activated Cell Sorter (microFACS) for astrobiology applications is under development. This device is designed to have a footprint of 7 cm x 7 cm x 4 cm and allow live-dead counts and sorting of cells that have fluorescent characteristics from staining. The FACS system takes advantage of microfluidics to create a cell sorter that can fit in the palm of the hand. A micron-scale channel allows cells to pass by a blue diode which causes emission of marker-expressed cells which are detected by a filtered photodetector. A small microcontroller then counts cells and operates high speed valves to select which chamber the cell is collected in (a collection chamber or a waste chamber). Cells with the expressed characteristic will be collected in the collection chamber. This system has been built and is currently being tested. We are also designing a system with integrated MEMS-based pumps and valves for a small and compact unit to fly on small satellite-based biology experiments.

Ultra-Thin Dual-Band Polarization-Insensitive and Wide-Angle Perfect Metamaterial Absorber Based on a Single Circular Sector Resonator Structure

NASA Astrophysics Data System (ADS)

Luo, Hao; Cheng, Yong Zhi

2018-01-01

We present a simple design for an ultra-thin dual-band polarization-insensitive and wide-angle perfect metamaterial absorber (PMMA) based on a single circular sector resonator structure (CSRS). Both simulation and experimental results reveal that two resonance peaks with average absorption above 99% can be achieved. The dual-band PMMA is ultra-thin with total thickness of 0.5 mm, which is

Incidence, management and outcome of women requiring massive transfusion after childbirth in the Netherlands: secondary analysis of a nationwide cohort study between 2004 and 2006.

PubMed

Ramler, Paul I; van den Akker, Thomas; Henriquez, Dacia D C A; Zwart, Joost J; van Roosmalen, Jos

2017-06-19

Postpartum hemorrhage remains the leading cause of maternal morbidity and mortality worldwide. Few population-based studies have examined the epidemiology of massive transfusion for postpartum hemorrhage. The aim of this study was to determine the incidence, management, and outcomes of women with postpartum hemorrhage who required massive transfusion in the Netherlands between 2004 and 2006. Data for all women from a gestational age of 20 weeks onwards who had postpartum hemorrhage requiring eight or more red blood cell concentrates were obtained from a nationwide population-based cohort study including all 98 hospitals with a maternity unit in the Netherlands. Three hundred twenty-seven women who had postpartum hemorrhage requiring massive transfusion were identified (massive transfusion rate 91 per 100,000 deliveries (95% confidence interval: 81-101)). The median blood loss was 4500 mL (interquartile range 3250-6000 mL) and the median number of red blood cell concentrates transfused was 11 units (interquartile range 9-16 units). Among women receiving massive transfusion, the most common cause of hemorrhage was uterine atony. Eighty-three women (25%) underwent hysterectomy, 227 (69%) were admitted to an intensive care unit, and three women died (case fatality rate 0,9%). The number of women in the Netherlands who had postpartum hemorrhage treated with massive transfusion was relatively high compared to other comparable settings. Evidence-based uniform management guidelines are necessary.

Physical Principles of Development of the State Standard of Biological Cell Polarizability

NASA Astrophysics Data System (ADS)

Shuvalov, G. V.; Generalov, K. V.; Generalov, V. M.; Kruchinina, M. V.; Koptev, E. S.; Minin, O. V.; Minin, I. V.

2018-03-01

A new state standard of biological cell polarizability based on micron-size latex particles has been developed. As a standard material, it is suggested to use polystyrene. Values of the polarizability calculated for erythrocytes and values of the polarizability of micron-size spherical latex particles measured with measuring-computing complexes agree within the limits of satisfactory relative error. The Standard allows one the unit of polarizability measurements [m3] to be assigned to cells and erythrocytes for the needs of medicine.

A modular cell-based biosensor using engineered genetic logic circuits to detect and integrate multiple environmental signals

PubMed Central

Wang, Baojun; Barahona, Mauricio; Buck, Martin

2013-01-01

Cells perceive a wide variety of cellular and environmental signals, which are often processed combinatorially to generate particular phenotypic responses. Here, we employ both single and mixed cell type populations, pre-programmed with engineered modular cell signalling and sensing circuits, as processing units to detect and integrate multiple environmental signals. Based on an engineered modular genetic AND logic gate, we report the construction of a set of scalable synthetic microbe-based biosensors comprising exchangeable sensory, signal processing and actuation modules. These cellular biosensors were engineered using distinct signalling sensory modules to precisely identify various chemical signals, and combinations thereof, with a quantitative fluorescent output. The genetic logic gate used can function as a biological filter and an amplifier to enhance the sensing selectivity and sensitivity of cell-based biosensors. In particular, an Escherichia coli consortium-based biosensor has been constructed that can detect and integrate three environmental signals (arsenic, mercury and copper ion levels) via either its native two-component signal transduction pathways or synthetic signalling sensors derived from other bacteria in combination with a cell-cell communication module. We demonstrate how a modular cell-based biosensor can be engineered predictably using exchangeable synthetic gene circuit modules to sense and integrate multiple-input signals. This study illustrates some of the key practical design principles required for the future application of these biosensors in broad environmental and healthcare areas. PMID:22981411

Growing Stem Cells: The Impact of Federal Funding Policy on the U.S. Scientific Frontier

ERIC Educational Resources Information Center

Furman, Jeffrey L.; Murray, Fiona; Stern, Scott

2012-01-01

This paper articulates a citation-based approach to science policy evaluation and employs that approach to investigate the impact of the United States' 2001 policy regarding the federal funding of human embryonic stem cell (hESC) research. We evaluate the impact of the policy on the level of U.S. hESC research, the U.S. position at the knowledge…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yasuda, H.; Chong, C.; Charalampidis, E. G.

Here, we investigate the nonlinear wave dynamics of origami-based metamaterials composed of Tachi-Miura polyhedron (TMP) unit cells. These cells exhibit strain softening behavior under compression, which can be tuned by modifying their geometrical configurations or initial folded conditions. We assemble these TMP cells into a cluster of origami-based metamaterials, and we theoretically model and numerically analyze their wave transmission mechanism under external impact. Numerical simulations show that origami-based metamaterials can provide a prototypical platform for the formation of nonlinear coherent structures in the form of rarefaction waves, which feature a tensile wavefront upon the application of compression to the system.more » We also demonstrate the existence of numerically exact traveling rarefaction waves in an effective lumped-mass model. Origami-based metamaterials can be highly useful for mitigating shock waves, potentially enabling a wide variety of engineering applications.« less

Formation of rarefaction waves in origami-based metamaterials

DOE PAGES

Yasuda, H.; Chong, C.; Charalampidis, E. G.; ...

2016-04-15

Here, we investigate the nonlinear wave dynamics of origami-based metamaterials composed of Tachi-Miura polyhedron (TMP) unit cells. These cells exhibit strain softening behavior under compression, which can be tuned by modifying their geometrical configurations or initial folded conditions. We assemble these TMP cells into a cluster of origami-based metamaterials, and we theoretically model and numerically analyze their wave transmission mechanism under external impact. Numerical simulations show that origami-based metamaterials can provide a prototypical platform for the formation of nonlinear coherent structures in the form of rarefaction waves, which feature a tensile wavefront upon the application of compression to the system.more » We also demonstrate the existence of numerically exact traveling rarefaction waves in an effective lumped-mass model. Origami-based metamaterials can be highly useful for mitigating shock waves, potentially enabling a wide variety of engineering applications.« less

AutoCellSeg: robust automatic colony forming unit (CFU)/cell analysis using adaptive image segmentation and easy-to-use post-editing techniques.

PubMed

Khan, Arif Ul Maula; Torelli, Angelo; Wolf, Ivo; Gretz, Norbert

2018-05-08

In biological assays, automated cell/colony segmentation and counting is imperative owing to huge image sets. Problems occurring due to drifting image acquisition conditions, background noise and high variation in colony features in experiments demand a user-friendly, adaptive and robust image processing/analysis method. We present AutoCellSeg (based on MATLAB) that implements a supervised automatic and robust image segmentation method. AutoCellSeg utilizes multi-thresholding aided by a feedback-based watershed algorithm taking segmentation plausibility criteria into account. It is usable in different operation modes and intuitively enables the user to select object features interactively for supervised image segmentation method. It allows the user to correct results with a graphical interface. This publicly available tool outperforms tools like OpenCFU and CellProfiler in terms of accuracy and provides many additional useful features for end-users.

Differences in reward processing between putative cell types in primate prefrontal cortex

PubMed Central

Fan, Hongwei; Wang, Rubin; Sakagami, Masamichi

2017-01-01

Single-unit studies in monkeys have demonstrated that neurons in the prefrontal cortex predict the reward type, reward amount or reward availability associated with a stimulus. To examine contributions of pyramidal cells and interneurons in reward processing, single-unit activity was extracellularly recorded in prefrontal cortices of four monkeys performing a reward prediction task. Based on their shapes of spike waveforms, prefrontal neurons were classified into broad-spike and narrow-spike units that represented putative pyramidal cells and interneurons, respectively. We mainly observed that narrow-spike neurons showed higher firing rates but less bursty discharges than did broad-spike neurons. Both narrow-spike and broad-spike cells selectively responded to the stimulus, reward and their interaction, and the proportions of each type of selective neurons were similar between the two cell classes. Moreover, the two types of cells displayed equal reliability of reward or stimulus discrimination. Furthermore, we found that broad-spike and narrow-spike cells showed distinct mechanisms for encoding reward or stimulus information. Broad-spike neurons raised their firing rate relative to the baseline rate to represent the preferred reward or stimulus information, whereas narrow-spike neurons inhibited their firing rate lower than the baseline rate to encode the non-preferred reward or stimulus information. Our results suggest that narrow-spike and broad-spike cells were equally involved in reward and stimulus processing in the prefrontal cortex. They utilized a binary strategy to complementarily represent reward or stimulus information, which was consistent with the task structure in which the monkeys were required to remember two reward conditions and two visual stimuli. PMID:29261734

Differences in reward processing between putative cell types in primate prefrontal cortex.

PubMed

Fan, Hongwei; Pan, Xiaochuan; Wang, Rubin; Sakagami, Masamichi

2017-01-01

Single-unit studies in monkeys have demonstrated that neurons in the prefrontal cortex predict the reward type, reward amount or reward availability associated with a stimulus. To examine contributions of pyramidal cells and interneurons in reward processing, single-unit activity was extracellularly recorded in prefrontal cortices of four monkeys performing a reward prediction task. Based on their shapes of spike waveforms, prefrontal neurons were classified into broad-spike and narrow-spike units that represented putative pyramidal cells and interneurons, respectively. We mainly observed that narrow-spike neurons showed higher firing rates but less bursty discharges than did broad-spike neurons. Both narrow-spike and broad-spike cells selectively responded to the stimulus, reward and their interaction, and the proportions of each type of selective neurons were similar between the two cell classes. Moreover, the two types of cells displayed equal reliability of reward or stimulus discrimination. Furthermore, we found that broad-spike and narrow-spike cells showed distinct mechanisms for encoding reward or stimulus information. Broad-spike neurons raised their firing rate relative to the baseline rate to represent the preferred reward or stimulus information, whereas narrow-spike neurons inhibited their firing rate lower than the baseline rate to encode the non-preferred reward or stimulus information. Our results suggest that narrow-spike and broad-spike cells were equally involved in reward and stimulus processing in the prefrontal cortex. They utilized a binary strategy to complementarily represent reward or stimulus information, which was consistent with the task structure in which the monkeys were required to remember two reward conditions and two visual stimuli.

Cell phone use among homeless youth: potential for new health interventions and research.

PubMed

Rice, Eric; Lee, Alex; Taitt, Sean

2011-12-01

Cell phone use has become nearly ubiquitous among adolescents in the United States. Despite the potential for cell phones to facilitate intervention, research, and care for homeless youth, no data exists to date on cell phone use among this population. In 2009, a survey of cell phone use was conducted among a non-probability sample of 169 homeless youth in Los Angeles, CA. Levels of ownership and use, instrumental uses (connecting to case workers, employers) and patterns of connecting to various network types were assessed (family, home-based peers, street-based peers). Differences in socio-demographic characteristics and cell phone ownership were assessed via t test and chi-square statistics. Sixty-two percent of homeless youth own a cell phone; 40% have a working phone. Seventeen percent used their phone to call a case manager, 36% to call either a potential or current employer. Fifty-one percent of youth connected with home-based peers on the phone and 41% connected to parents. Cell phones present new opportunities for intervention research, connecting homeless youth to family and home-based peers who can be sources of social support in times of need. Moreover, cell phones provide researchers and providers with new avenues to maintain connections with these highly transient youth.

Common-path digital holographic microscopy based on a beam displacer unit

NASA Astrophysics Data System (ADS)

Di, Jianglei; Zhang, Jiwei; Song, Yu; Wang, Kaiqiang; Wei, Kun; Zhao, Jianlin

2018-02-01

Digital holographic microscopy (DHM) has become a novel tool with advantages of full field, non-destructive, high-resolution and 3D imaging, which captures the quantitative amplitude and phase information of microscopic specimens. It's a well-established method for digital recording and numerical reconstructing the full complex field of wavefront of the samples with a diffraction-limited lateral resolution down to 0.3 μm depending on the numerical aperture of microscope objective. Meanwhile, its axial resolution through axial direction is less than 10 nm due to the interferometric nature in phase imaging. Compared with the typical optical configurations such as Mach-Zehnder interferometer and Michelson interferometer, the common-path DHM has the advantages of simple and compact configuration, high stability, and so on. Here, a simple, compact, and low-cost common-path DHM based on a beam displacer unit is proposed for quantitative phase imaging of biological cells. The beam displacer unit is completely compatible with commercial microscope and can be easily set up in the output port of the microscope as a compact independent device. This technique can be used to achieve the quantitative phase measurement of biological cells with an excellent temporal stability of 0.51 nm, which makes it having a good prospect in the fields of biological and medical science. Living mouse osteoblastic cells are quantitatively measured with the system to demonstrate its capability and applicability.

Speech recognition systems on the Cell Broadband Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Y; Jones, H; Vaidya, S

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 thousandsmore » 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.« less

Efficient sensitization of dye-sensitized solar cells by novel triazine-bridged porphyrin-porphyrin dyads.

PubMed

Zervaki, Galateia E; Roy, Mahesh S; Panda, Manas K; Angaridis, Panagiotis A; Chrissos, Emmanouel; Sharma, Ganesh D; Coutsolelos, Athanassios G

2013-09-03

Two novel porphyrin-porphyrin dyads, the symmetrical Zn[Porph]-Zn[Porph] (2) and unsymmetrical Zn[Porph]-H2[Porph] (4), where Zn[Porph] and H2[Porph] are the metalated and free-base forms of 5-(4-aminophenyl)-10,15,20-triphenylporphyrin, respectively, in which two porphyrin units are covalently bridged by 1,3,5-triazine, have been synthesized via the stepwise amination of cyanuric chloride. The dyads are also functionalized by a terminal carboxylic acid group of a glycine moiety attached to the triazine group. Photophysical measurements of 2 and 4 showed broaden and strengthened absorptions in their visible spectra, while electrochemistry experiments and density functional theory calculations revealed negligible interaction between the two porphyrin units in their ground states but appropriate frontier orbital energy levels for use in dye-sensitized solar cells (DSSCs). The 2- and 4-based solar cells have been fabricated and found to exhibit power conversion efficiencies (PCEs) of 3.61% and 4.46%, respectively (under an illumination intensity of 100 mW/cm(2) with TiO2 films of 10 μm thickness). The higher PCE value of the 4-based DSSC, as revealed by photovoltaic measurements (J-V curves) and incident photon-to-current conversion efficiency (IPCE) spectra of the two cells, is attributed to its enhanced short-circuit current (J(sc)) under illumination, high open-circuit voltage (V(oc)), and fill factor (FF) values. Electrochemical impedance spectra demonstrated shorter electron-transport time (τd), longer electron lifetime (τe), and high charge recombination resistance for the 4-based cell, as well as larger dye loading onto TiO2.

Advantages and challenges of microfluidic cell culture in polydimethylsiloxane devices.

PubMed

Halldorsson, Skarphedinn; Lucumi, Edinson; Gómez-Sjöberg, Rafael; Fleming, Ronan M T

2015-01-15

Culture of cells using various microfluidic devices is becoming more common within experimental cell biology. At the same time, a technological radiation of microfluidic cell culture device designs is currently in progress. Ultimately, the utility of microfluidic cell culture will be determined by its capacity to permit new insights into cellular function. Especially insights that would otherwise be difficult or impossible to obtain with macroscopic cell culture in traditional polystyrene dishes, flasks or well-plates. Many decades of heuristic optimization have gone into perfecting conventional cell culture devices and protocols. In comparison, even for the most commonly used microfluidic cell culture devices, such as those fabricated from polydimethylsiloxane (PDMS), collective understanding of the differences in cellular behavior between microfluidic and macroscopic culture is still developing. Moving in vitro culture from macroscopic culture to PDMS based devices can come with unforeseen challenges. Changes in device material, surface coating, cell number per unit surface area or per unit media volume may all affect the outcome of otherwise standard protocols. In this review, we outline some of the advantages and challenges that may accompany a transition from macroscopic to microfluidic cell culture. We focus on decisive factors that distinguish macroscopic from microfluidic cell culture to encourage a reconsideration of how macroscopic cell culture principles might apply to microfluidic cell culture. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Power management circuits for self-powered systems based on micro-scale solar energy harvesting

NASA Astrophysics Data System (ADS)

Yoon, Eun-Jung; Yu, Chong-Gun

2016-03-01

In this paper, two types of power management circuits for self-powered systems based on micro-scale solar energy harvesting are proposed. First, if a solar cell outputs a very low voltage, less than 0.5 V, as in miniature solar cells or monolithic integrated solar cells, such that it cannot directly power the load, a voltage booster is employed to step up the solar cell's output voltage, and then a power management unit (PMU) delivers the boosted voltage to the load. Second, if the output voltage of a solar cell is enough to drive the load, the PMU directly supplies the load with solar energy. The proposed power management systems are designed and fabricated in a 0.18-μm complementary metal-oxide-semiconductor process, and their performances are compared and analysed through measurements.

On mechanics and material length scales of failure in heterogeneous interfaces using a finite strain high performance solver

NASA Astrophysics Data System (ADS)

Mosby, Matthew; Matouš, Karel

2015-12-01

Three-dimensional simulations capable of resolving the large range of spatial scales, from the failure-zone thickness up to the size of the representative unit cell, in damage mechanics problems of particle reinforced adhesives are presented. We show that resolving this wide range of scales in complex three-dimensional heterogeneous morphologies is essential in order to apprehend fracture characteristics, such as strength, fracture toughness and shape of the softening profile. Moreover, we show that computations that resolve essential physical length scales capture the particle size-effect in fracture toughness, for example. In the vein of image-based computational materials science, we construct statistically optimal unit cells containing hundreds to thousands of particles. We show that these statistically representative unit cells are capable of capturing the first- and second-order probability functions of a given data-source with better accuracy than traditional inclusion packing techniques. In order to accomplish these large computations, we use a parallel multiscale cohesive formulation and extend it to finite strains including damage mechanics. The high-performance parallel computational framework is executed on up to 1024 processing cores. A mesh convergence and a representative unit cell study are performed. Quantifying the complex damage patterns in simulations consisting of tens of millions of computational cells and millions of highly nonlinear equations requires data-mining the parallel simulations, and we propose two damage metrics to quantify the damage patterns. A detailed study of volume fraction and filler size on the macroscopic traction-separation response of heterogeneous adhesives is presented.

Alkaline Comet Assay for Assessing DNA Damage in Individual Cells.

PubMed

Pu, Xinzhu; Wang, Zemin; Klaunig, James E

2015-08-06

Single-cell gel electrophoresis, commonly called a comet assay, is a simple and sensitive method for assessing DNA damage at the single-cell level. It is an important technique in genetic toxicological studies. The comet assay performed under alkaline conditions (pH >13) is considered the optimal version for identifying agents with genotoxic activity. The alkaline comet assay is capable of detecting DNA double-strand breaks, single-strand breaks, alkali-labile sites, DNA-DNA/DNA-protein cross-linking, and incomplete excision repair sites. The inclusion of digestion of lesion-specific DNA repair enzymes in the procedure allows the detection of various DNA base alterations, such as oxidative base damage. This unit describes alkaline comet assay procedures for assessing DNA strand breaks and oxidative base alterations. These methods can be applied in a variety of cells from in vitro and in vivo experiments, as well as human studies. Copyright © 2015 John Wiley & Sons, Inc.

Charge-Control Unit for Testing Lithium-Ion Cells

NASA Technical Reports Server (NTRS)

Reid, Concha M.; Mazo, Michelle A.; Button, Robert M.

2008-01-01

A charge-control unit was developed as part of a program to validate Li-ion cells packaged together in batteries for aerospace use. The lithium-ion cell charge-control unit will be useful to anyone who performs testing of battery cells for aerospace and non-aerospace uses and to anyone who manufacturers battery test equipment. This technology reduces the quantity of costly power supplies and independent channels that are needed for test programs in which multiple cells are tested. Battery test equipment manufacturers can integrate the technology into their battery test equipment as a method to manage charging of multiple cells in series. The unit manages a complex scheme that is required for charging Li-ion cells electrically connected in series. The unit makes it possible to evaluate cells together as a pack using a single primary test channel, while also making it possible to charge each cell individually. Hence, inherent cell-to-cell variations in a series string of cells can be addressed, and yet the cost of testing is reduced substantially below the cost of testing each cell as a separate entity. The unit consists of electronic circuits and thermal-management devices housed in a common package. It also includes isolated annunciators to signal when the cells are being actively bypassed. These annunciators can be used by external charge managers or can be connected in series to signal that all cells have reached maximum charge. The charge-control circuitry for each cell amounts to regulator circuitry and is powered by that cell, eliminating the need for an external power source or controller. A 110-VAC source of electricity is required to power the thermal-management portion of the unit. A small direct-current source can be used to supply power for an annunciator signal, if desired.

Selective Laser Melting: a regular unit cell approach for the manufacture of porous, titanium, bone in-growth constructs, suitable for orthopedic applications.

PubMed

Mullen, Lewis; Stamp, Robin C; Brooks, Wesley K; Jones, Eric; Sutcliffe, Christopher J

2009-05-01

In this study, a novel porous titanium structure for the purpose of bone in-growth has been designed, manufactured and evaluated. The structure was produced by Selective Laser Melting (SLM); a rapid manufacturing process capable of producing highly intricate, functionally graded parts. The technique described utilizes an approach based on a defined regular unit cell to design and produce structures with a large range of both physical and mechanical properties. These properties can be tailored to suit specific requirements; in particular, functionally graded structures with bone in-growth surfaces exhibiting properties comparable to those of human bone have been manufactured. The structures were manufactured and characterized by unit cell size, strand diameter, porosity, and compression strength. They exhibited a porosity (10-95%) dependant compression strength (0.5-350 Mpa) comparable to the typical naturally occurring range. It is also demonstrated that optimized structures have been produced that possesses ideal qualities for bone in-growth applications and that these structures can be applied in the production of orthopedic devices. (c) 2008 Wiley Periodicals, Inc.

Improving Photovoltaic Performance of a Fused-Ring Azepinedione Copolymer via a D-A-A Design.

PubMed

Zhang, Honghong; Li, Ting; Xiao, Zuo; Lei, Zhongli; Ding, Liming

2018-04-01

Two conjugated copolymer donors, PTTABDT and PBTTABDT, based on a fused-ring azepinedione acceptor unit, 5-(2-octyldodecyl)-4H-thieno[2',3':4,5]thieno[3,2-c]thieno[2',3':4,5]thieno[2,3-e]azepine-4,6(5H)-dione (TTA), are prepared. PTTABDT possesses a conventional donor-acceptor (D-A) structure with one TTA in the repeat unit, while PBTTABDT has a D-A-A structure with two TTAs in the repeat unit. Compared with PTTABDT, PBTTABDT shows a deeper highest occupied molecular orbital (HOMO) level, a narrower bandgap, and a higher hole mobility, and exhibits better performance in bulk heterojunction solar cells. Power conversion efficiencies of 6.18% and 7.81% are achieved from PTTABDT:PC 71 BM and PBTTABDT:PC 71 BM solar cells, respectively. The higher performance of PBTTABDT:PC 71 BM solar cells results from the enhanced open-circuit voltage (V oc ) and short-circuit current density (  J sc ). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Origami-based mechanical metamaterials with tunable frequency band structures (Conference Presentation)

NASA Astrophysics Data System (ADS)

Yasuda, Hiromi; Pratt, Riley; Yang, Jinkyu

2017-04-01

We investigate wave dynamics in origami-based mechanical metamaterials composed of bellows-like origami structures, specifically the Tachi-Miura Polyhedron (TMP). One of the unique features of the TMP is that its structural deformations take place only along the crease lines, therefore the structure can be made of rigid plates and hinges. By utilizing this feature, we introduce linear torsional springs to model the crease lines and derive the force and displacement relationship of the TMP structure along the longitudinal direction. Our analysis shows strain softening/hardening behaviors in compression/tensile regions respectively, and the force-displacement curve can be manipulated by altering the initial configuration of the TMP (e.g., the initial folding angle). We also fabricate physical prototypes and measure the force-displacement behavior to verify our analytical model. Based on this static analysis on the TMP, we simplify the TMP structure into a linkage model, preserving the tunable strain softening/hardening behaviors. Dynamic analysis is also conducted numerically to analyze the frequency response of the simplified TMP unit cell under harmonic excitations. The simplified TMP exhibits a transition between linear and nonlinear behaviors, which depends on the amplitude of the excitation and the initial configuration. In addition, we design a 1D system composed of simplified TMP unit cells and analyze the relationship between frequency and wave number. If two different configurations of the unit cell (e.g., different initial folding angles) are connected in an alternating arrangement, the system develops frequency bandgaps. These unique static/dynamic behaviors can be exploited to design engineering devices which can handle vibrations and impact in an efficient manner.

Calculation of optical parameters for covalent binary alloys used in optical memories/solar cells: a modified approach

NASA Astrophysics Data System (ADS)

Bhatnagar, Promod K.; Gupta, Poonam; Singh, Laxman

2001-06-01

Chalcogenide based alloys find applications in a number of devices like optical memories, IR detectors, optical switches, photovoltaics, compound semiconductor heterosrtuctures etc. We have modified the Gurman's statistical thermodynamic model (STM) of binary covalent alloys. In the Gurman's model, entropy calculations are based on the number of structural units present. The need to modify this model arose due to the fact that it gives equal probability for all the tetrahedra present in the alloy. We have modified the Gurman's model by introducing the concept that the entropy is based on the bond arrangement rather than that on the structural units present. In the present work calculation based on this modification have been presented for optical properties, which find application in optical switching/memories, solar cells and other optical devices. It has been shown that the calculated optical parameters (for a typical case of GaxSe1-x) based on modified model are closer to the available experimental results. These parameters include refractive index, extinction coefficient, dielectric functions, optical band gap etc. GaxSe1-x has been found to be suitable for reversible optical memories also, where phase change (a yields c and vice versa) takes place at specified physical conditions. DTA/DSC studies also suggest the suitability of this material for optical switching/memory applications. We have also suggested possible use of GaxSe1-x (x = 0.4) in place of oxide layer in a Metal - Oxide - Semiconductor type solar cells. The new structure is Metal - Ga2Se3 - GaAs. The I-V characteristics and other parameters calculated for this structure are found to be much better than that for Si based solar cells. Maximum output power is obtained at the intermediate layer thickness approximately 40 angstroms for this typical solar cell.

Annular feed air breathing fuel cell stack

DOEpatents

Wilson, Mahlon S.; Neutzler, Jay K.

1997-01-01

A stack of polymer electrolyte fuel cells is formed from a plurality of unit cells where each unit cell includes fuel cell components defining a periphery and distributed along a common axis, where the fuel cell components include a polymer electrolyte membrane, an anode and a cathode contacting opposite sides of the membrane, and fuel and oxygen flow fields contacting the anode and the cathode, respectively, wherein the components define an annular region therethrough along the axis. A fuel distribution manifold within the annular region is connected to deliver fuel to the fuel flow field in each of the unit cells. The fuel distribution manifold is formed from a hydrophilic-like material to redistribute water produced by fuel and oxygen reacting at the cathode. In a particular embodiment, a single bolt through the annular region clamps the unit cells together. In another embodiment, separator plates between individual unit cells have an extended radial dimension to function as cooling fins for maintaining the operating temperature of the fuel cell stack.

Solid oxide fuel cell with multi-unit construction and prismatic design

DOEpatents

McPheeters, C.C.; Dees, D.W.; Myles, K.M.

1999-03-16

A single cell unit of a solid oxide fuel cell is described that is individually fabricated and sintered prior to being connected to adjacent cells to form a solid oxide fuel cell. The single cell unit is comprised of a shaped anode sheet positioned between a flat anode sheet and an anode-electrolyte-cathode (A/E/C) sheet, and a shaped cathode sheet positioned between the A/E/C sheet and a cathode-interconnect-anode (C/I/A) sheet. An alternate embodiment comprises a shaped cathode sheet positioned between an A/E/C sheet and a C/I/A sheet. The shaped sheets form channels for conducting reactant gases. Each single cell unit is individually sintered to form a finished sub-assembly. The finished sub-assemblies are connected in electrical series by interposing connective material between the end surfaces of adjacent cells, whereby individual cells may be inspected for defects and interchanged with non-defective single cell units. 7 figs.

Fresenius AS.TEC204 blood cell separator.

PubMed

Sugai, Mikiya

2003-02-01

Fresenius AS.TEC204 is a third-generation blood cell separator that incorporates the continuous centrifugal separation method and automatic control of the cell separation process. Continuous centrifugation separates cell components according to their specific gravity, and different cell components are either harvested or eliminated as needed. The interface between the red blood cell and plasma is optically detected, and the Interface Control (IFC) cooperates with different pumps, monitors and detectors to harvest required components automatically. The system is composed of three major sections; the Front Panel Unit; the Pump Unit, and the Centrifuge Unit. This unit can be used for a wide variety of clinical applications including collection of platelets, peripheral blood stem cells, bone marrow stem cells, granulocytes, mononuclear cells, and exchange of plasma or red cells, and for plasma treatment.

Continuous Manufacturing of Recombinant Therapeutic Proteins: Upstream and Downstream Technologies.

PubMed

Patil, Rohan; Walther, Jason

2017-03-07

Continuous biomanufacturing of recombinant therapeutic proteins offers several potential advantages over conventional batch processing, including reduced cost of goods, more flexible and responsive manufacturing facilities, and improved and consistent product quality. Although continuous approaches to various upstream and downstream unit operations have been considered and studied for decades, in recent years interest and application have accelerated. Researchers have achieved increasingly higher levels of process intensification, and have also begun to integrate different continuous unit operations into larger, holistically continuous processes. This review first discusses approaches for continuous cell culture, with a focus on perfusion-enabling cell separation technologies including gravitational, centrifugal, and acoustic settling, as well as filtration-based techniques. We follow with a review of various continuous downstream unit operations, covering categories such as clarification, chromatography, formulation, and viral inactivation and filtration. The review ends by summarizing case studies of integrated and continuous processing as reported in the literature.

Buckling behavior of origami unit cell facets under compressive loads

NASA Astrophysics Data System (ADS)

Kshad, Mohamed Ali Emhmed; Naguib, Hani E.

2018-03-01

Origami structures as cores for sandwich structures are designed to withstand the compressive loads and to dissipate compressive energy. The deformation of the origami panels and the unit cell facets are the primary factors behind the compressive energy dissipation in origami structures. During the loading stage, the origami structures deform through the folding and unfolding process of the unit cell facets, and also through the plastic deformation of the facets. This work presents a numerical study of the buckling behavior of different origami unit cell elements under compressive loading. The studied origami configurations were Miura and Ron-Resch-like origami structures. Finite element package was used to model the origami structures. The study investigated the buckling behavior of the unit cell facets of two types of origami structures Miura origami and Ron-Resch-Like origami structures. The simulation was conducted using ANSYS finite element software, in which the model of the unit cell represented by shell elements, and the eigenvalues buckling solver was used to predict the theoretical buckling of the unit cell elements.

Approximating the stress field within the unit cell of a fabric reinforced composite using replacement elements

NASA Technical Reports Server (NTRS)

Foye, R. L.

1993-01-01

This report concerns the prediction of the elastic moduli and the internal stresses within the unit cell of a fabric reinforced composite. In the proposed analysis no restrictions or assumptions are necessary concerning yarn or tow cross-sectional shapes or paths through the unit cell but the unit cell itself must be a right hexagonal parallelepiped. All the unit cell dimensions are assumed to be small with respect to the thickness of the composite structure that it models. The finite element analysis of a unit cell is usually complicated by the mesh generation problems and the non-standard, adjacent-cell boundary conditions. This analysis avoids these problems through the use of preprogrammed boundary conditions and replacement materials (or elements). With replacement elements it is not necessary to match all the constitutional material interfaces with finite element boundaries. Simple brick-shaped elements can be used to model the unit cell structure. The analysis predicts the elastic constants and the average stresses within each constituent material of each brick element. The application and results of this analysis are demonstrated through several example problems which include a number of composite microstructures.

Techno-economic analysis of fuel cell auxiliary power units as alternative to idling

NASA Astrophysics Data System (ADS)

Jain, Semant; Chen, Hsieh-Yeh; Schwank, Johannes

This paper presents a techno-economic analysis of fuel-cell-based auxiliary power units (APUs), with emphasis on applications in the trucking industry and the military. The APU system is intended to reduce the need for discretionary idling of diesel engines or gas turbines. The analysis considers the options for on-board fuel processing of diesel and compares the two leading fuel cell contenders for automotive APU applications: proton exchange membrane fuel cell and solid oxide fuel cell. As options for on-board diesel reforming, partial oxidation and auto-thermal reforming are considered. Finally, using estimated and projected efficiency data, fuel consumption patterns, capital investment, and operating costs of fuel-cell APUs, an economic evaluation of diesel-based APUs is presented, with emphasis on break-even periods as a function of fuel cost, investment cost, idling time, and idling efficiency. The analysis shows that within the range of parameters studied, there are many conditions where deployment of an SOFC-based APU is economically viable. Our analysis indicates that at an APU system cost of 100 kW -1, the economic break-even period is within 1 year for almost the entire range of conditions. At 500 kW -1 investment cost, a 2-year break-even period is possible except for the lowest end of the fuel consumption range considered. However, if the APU investment cost is 3000 kW -1, break-even would only be possible at the highest fuel consumption scenarios. For Abram tanks, even at typical land delivered fuel costs, a 2-year break-even period is possible for APU investment costs as high as 1100 kW -1.

Drinking-water arsenic exposure modulates gene expression in human lymphocytes from a U.S. population.

PubMed

Andrew, Angeline S; Jewell, David A; Mason, Rebecca A; Whitfield, Michael L; Moore, Jason H; Karagas, Margaret R

2008-04-01

Arsenic exposure impairs development and can lead to cancer, cardiovascular disease, and diabetes. The mechanism underlying these effects remains unknown. Primarily because of geologic sources of contamination, drinking-water arsenic levels are above the current recommended maximum contaminant level of 10 microg/L in the northeastern, western, and north central regions of the United States. We investigated the effects of arsenic exposure, defined by internal biomarkers at levels relevant to the United States and similarly exposed populations, on gene expression. We conducted separate Affymetrix microarray-based genomewide analyses of expression patterns. Peripheral blood lymphocyte samples from 21 controls interviewed (1999-2002) as part of a case-control study in New Hampshire were selected based on high- versus low-level arsenic exposure levels. The biologic functions of the transcripts that showed statistically significant abundance differences between high- and low-arsenic exposure groups included an overrepresentation of genes involved in defense response, immune function, cell growth, apoptosis, regulation of cell cycle, T-cell receptor signaling pathway, and diabetes. Notably, the high-arsenic exposure group exhibited higher levels of several killer cell immunoglobulin-like receptors that inhibit natural killer cell activity. These findings define biologic changes that occur with chronic arsenic exposure in humans and provide leads and potential targets for understanding and monitoring the pathogenesis of arsenic-induced diseases.

CD1c presentation of synthetic glycolipid antigens with foreign alkyl branching motifs

PubMed Central

de Jong, Annemieke; Arce, Eva Casas; Cheng, Tan-Yun; van Summeren, Ruben P.; Feringa, Ben L.; Dudkin, Vadim; Crich, David; Matsunaga, Isamu; Minnaard, Adriaan J.; Moody, D. Branch

2009-01-01

Summary Human CD1c is a protein that activates αβ T cells by presenting self antigens, synthetic mannosyl phosphodolichols and mycobacterial mannosyl phosphopolyketides. To determine which molecular structures of antigens mediate a T cell response, we measured activation by structurally divergent M. tuberculosis mannosyl-β1-phosphomycoketides as well as by synthetic analogs produced by two methods that yield either stereorandom or stereospecific methyl branching patterns. T cell responses required both a phosphate and a β-linked mannose unit, and showed preference for C30–34 lipid units with methyl branches in the S-configuration. Thus, in all cases T cell responses were strongest for synthetic compounds that mimicked the natural branched lipids produced by mycobacterial polyketide synthase 12. Incorporation of methylmalonate to form branched lipids is a common bacterial lipid synthesis pathway that is absent in vertebrates, so the preferential recognition of branched lipids may represent a new type of lipid-based pathogen associated molecular pattern (PAMP). PMID:18022562

Analysis of long-time operation of micro-cogeneration unit with fuel cell

NASA Astrophysics Data System (ADS)

Patsch, Marek; Čaja, Alexander

2015-05-01

Micro-cogeneration is cogeneration with small performance, with maximal electric power up to 50 kWe. On the present, there are available small micro-cogeneration units with small electric performance, about 1 kWe, which are usable also in single family houses or flats. These micro-cogeneration units operate on principle of conventional combustion engine, Stirling engine, steam engine or fuel cell. Micro-cogeneration units with fuel cells are new progressive developing type of units for single family houses. Fuel cell is electrochemical device which by oxidation-reduction reaction turn directly chemical energy of fuel to electric power, secondary products are pure water and thermal energy. The aim of paper is measuring and evaluation of operation parameters of micro-cogeneration unit with fuel cell which uses natural gas as a fuel.

Evaluation of the relationship between the Adenosine Triphosphate (ATP) bioluminescence assay and the presence of Bacillus anthracis spores and vegetative cells.

PubMed

Gibbs, Shawn G; Sayles, Harlan; Colbert, Erica M; Hewlett, Angela; Chaika, Oleg; Smith, Philip W

2014-05-28

The Adenosine triphosphate (ATP) bioluminescence assay was utilized in laboratory evaluations to determine the presence and concentration of vegetative and spore forms of Bacillus anthracis Sterne 34F2. Seventeen surfaces from the healthcare environment were selected for evaluation. Surfaces were inoculated with 50 µL of organism suspensions at three concentrations of 104, 106, 108 colony forming units per surface (CFU/surface) of B. anthracis. Culture-based methods and ATP based methods were utilized to determine concentrations. When all concentrations were evaluated together, a positive correlation between log-adjusted CFU and Relative Light Units (RLU) for endospores and vegetative cells was established. When concentrations were evaluated separately, a significant correlation was not demonstrated. This study demonstrated a positive correlation for ATP and culture-based methods for the vegetative cells of B. anthracis. When evaluating the endospores and combining both metabolic states, the ATP measurements and CFU recovered did not correspond to the initial concentrations on the evaluated surfaces. The results of our study show that the low ATP signal which does not correlate well to the CFU results would not make the ATP measuring devises effective in confirming contamination residual from a bioterrorist event.

Cell-based immunotherapy in gynecologic malignancies.

PubMed

Schaar, Bruce; Krishnan, Venkatesh; Tallapragada, Supreeti; Dorigo, Oliver

2018-02-01

To provide an overview of the principles, safety and efficacy of adoptive cell therapy (ACT) in solid tumors particularly in gynecological cancers. Efforts to target solid tumors using tumor-infiltrating lymphocytes and genetically modified T cells have shown promising efficacy in some patients. Two food and drug administration approvals for the treatment of leukemia are the first gene therapies available for cancer treatment in the United States. Genetic engineering of antitumor immunity using T cells has the potential to target specific tumor-associated antigens and overcome obstacles to successful immunotherapy like immune-suppressive factors in the tumor microenvironment.

Recycled Cell Phones - A Treasure Trove of Valuable Metals

USGS Publications Warehouse

Sullivan, Daniel E.

2006-01-01

This U.S. Geological Survey (USGS) Fact Sheet examines the potential value of recycling the metals found in obsolete cell phones. Cell phones seem ubiquitous in the United States and commonplace throughout most of the world. There were approximately 1 billion cell phones in use worldwide in 2002. In the United States, the number of cell phone subscribers increased from 340,000 in 1985 to 180 million in 2004. Worldwide, cell phone sales have increased from slightly more than 100 million units per year in 1997 to an estimated 779 million units per year in 2005. Cell phone sales are projected to exceed 1 billion units per year in 2009, with an estimated 2.6 billion cell phones in use by the end of that year. The U.S. Environmental Protection Agency estimated that, by 2005, as many as 130 million cell phones would be retired annually in the United States. The nonprofit organization INFORM, Inc., anticipated that, by 2005, a total of 500 million obsolete cell phones would have accumulated in consumers' desk drawers, store rooms, or other storage, awaiting disposal. Typically, cell phones are used for only 1 1/2 years before being replaced. Less than 1 percent of the millions of cell phones retired and discarded annually are recycled. When large numbers of cell phones become obsolete, large quantities of valuable metals end up either in storage or in landfills. The amount of metals potentially recoverable would make a significant addition to total metals recovered from recycling in the United States and would supplement virgin metals derived from mining.

A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications

PubMed Central

Islam, Md. Moinul; Islam, Mohammad Tariqul; Samsuzzaman, Md.; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah; Mansor, Mohd Fais

2015-01-01

A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm3, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4–12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications. PMID:28787945

Fuel Processing System for a 5kW Methanol Fuel Cell Power Unit.

DTIC Science & Technology

1985-11-27

report documents the development and design of a 5kW neat methanol reformer for phosphoric acid fuel cell power plants . The reformer design was based...VAPORIZATION OF METHANOL ........... 4.3 REFORMING/SHIFT CATALYST BED ......... 2 5.0 COMPONENT TESTING............... 5.1 COMBUSTION TUBE...69 36 Catalyst Bed Temperature Profile Before and After Transient ................. 70 37 Assembly -5kw Neat Methanol Reformer. ......... 72 Page No

ICSH guidelines for the verification and performance of automated cell counters for body fluids.

PubMed

Bourner, G; De la Salle, B; George, T; Tabe, Y; Baum, H; Culp, N; Keng, T B

2014-12-01

One of the many challenges facing laboratories is the verification of their automated Complete Blood Count cell counters for the enumeration of body fluids. These analyzers offer improved accuracy, precision, and efficiency in performing the enumeration of cells compared with manual methods. A patterns of practice survey was distributed to laboratories that participate in proficiency testing in Ontario, Canada, the United States, the United Kingdom, and Japan to determine the number of laboratories that are testing body fluids on automated analyzers and the performance specifications that were performed. Based on the results of this questionnaire, an International Working Group for the Verification and Performance of Automated Cell Counters for Body Fluids was formed by the International Council for Standardization in Hematology (ICSH) to prepare a set of guidelines to help laboratories plan and execute the verification of their automated cell counters to provide accurate and reliable results for automated body fluid counts. These guidelines were discussed at the ICSH General Assemblies and reviewed by an international panel of experts to achieve further consensus. © 2014 John Wiley & Sons Ltd.

Modeling and Characterization of Electrical Resistivity of Carbon Composite Laminates

NASA Astrophysics Data System (ADS)

Yasuda, Hiromi

Origami has recently received significant interest from the scientific and engineering communities as a method for designing building blocks of engineered structures to enhance their mechanical properties. However, the primary focus has been placed on their kinematic applications by leveraging the compactness and auxeticity of planar origami platforms. In this thesis, we study two different types of volumetric origami structures, Tachi-Miura Polyhedron (TMP) and Triangulated Cylindrical Origami (TCO), hierarchically from a single unit cell level to an assembly of multi-origami cells. We strategically assemble these origami cells into mechanical metamaterials and demonstrate their unique static/dynamic mechanical responses. In particular, these origami structures exhibit tailorable stiffness and strain softening/hardening behaviors, which leads to rich wave dynamics in origami-based architectures such as tunable frequency bands and new types of nonlinear wave propagations. One of the novel waveforms investigated in this thesis is the rarefaction solitary wave arising from strain-softening nature of origami unit cell. This unique wave dynamic mechanism is analyzed in numerical, analytical, and experimental approaches. By leveraging their tailorable folding mechanisms, the origami-based mechanical metamaterials can be used for designing new types of engineering devices and structures, not only for deployable space and disaster relief applications, but also for vibration filtering, impact mitigation, and energy harvesting.

Hematopoietic stem cell transplantation for non-Hodgkin lymphoma.

PubMed

Bhatt, Vijaya Raj; Vose, Julie M

2014-12-01

Up-front rituximab-based chemotherapy has improved outcomes in non-Hodgkin lymphoma (NHL); refractory or relapsed NHL still accounts for approximately 18,000 deaths in the United States. Autologous hematopoietic stem cell transplantation (SCT) can improve survival in primary refractory or relapsed aggressive NHL and mantle cell lymphoma and in relapsed follicular or peripheral T-cell lymphoma. Autologous SCT as a consolidation therapy after first complete or partial remission in high-risk aggressive NHL, mantle cell lymphoma, and peripheral T-cell lymphoma may improve progression-free survival. Allogeneic SCT offers a lower relapse rate but a higher nonrelapse mortality resulting in overall survival similar to autologous SCT. Copyright © 2014 Elsevier Inc. All rights reserved.

Applying Thienyl Side Chains and Different π-Bridge to Aromatic Side-Chain Substituted Indacenodithiophene-Based Small Molecule Donors for High-Performance Organic Solar Cells.

PubMed

Wang, Jin-Liang; Liu, Kai-Kai; Liu, Sha; Liu, Feng; Wu, Hong-Bin; Cao, Yong; Russell, Thomas P

2017-06-14

A pair of linear tetrafluorinated small molecular donors, named as ThIDTTh4F and ThIDTSe4F, which are with tetrathienyl-substituted IDT as electron-rich central core, electron-deficient difluorobenzothiadiazole as acceptor units, and donor end-capping groups, but having differences in the π-bridge (thiophene and selenophene), were successfully synthesized and evaluated as donor materials in organic solar cells. Such π-bridge and core units in these small molecules play a decisive role in the formation of the nanoscale separation of the blend films, which were systematically investigated through absorption spectra, grazing incidence X-ray diffraction pattern, transmission electron microscopy images, resonant soft X-ray scattering profiles, and charge mobility measurement. The ThIDTSe4F (with selenophene π-bridge)-based device exhibited superior performance than devices based on ThIDTh4F (with thiophene π-bridge) after post annealing treatment owing to optimized film morphology and improved charge transport. Power conversion efficiency of 7.31% and fill factor of ∼0.70 were obtained by using a blend of ThIDTSe4F and PC 71 BM with thermal annealing and solvent vapor annealing treatments, which is the highest PCE from aromatic side-chain substituted IDT-based small molecular solar cells. The scope of this study is to reveal the structure-property relationship of the aromatic side-chain substituted IDT-based donor materials as a function of π-bridge and the post annealing conditions.

Cell Sheet-Based Tissue Engineering for Organizing Anisotropic Tissue Constructs Produced Using Microfabricated Thermoresponsive Substrates.

PubMed

Takahashi, Hironobu; Okano, Teruo

2015-11-18

In some native tissues, appropriate microstructures, including orientation of the cell/extracellular matrix, provide specific mechanical and biological functions. For example, skeletal muscle is made of oriented myofibers that is responsible for the mechanical function. Native artery and myocardial tissues are organized three-dimensionally by stacking sheet-like tissues of aligned cells. Therefore, to construct any kind of complex tissue, the microstructures of cells such as myotubes, smooth muscle cells, and cardiomyocytes also need to be organized three-dimensionally just as in the native tissues of the body. Cell sheet-based tissue engineering allows the production of scaffold-free engineered tissues through a layer-by-layer construction technique. Recently, using microfabricated thermoresponsive substrates, aligned cells are being harvested as single continuous cell sheets. The cell sheets act as anisotropic tissue units to build three-dimensional tissue constructs with the appropriate anisotropy. This cell sheet-based technology is straightforward and has the potential to engineer a wide variety of complex tissues. In addition, due to the scaffold-free cell-dense environment, the physical and biological cell-cell interactions of these cell sheet constructs exhibit unique cell behaviors. These advantages will provide important clues to enable the production of well-organized tissues that closely mimic the structure and function of native tissues, required for the future of tissue engineering. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Units of analysis and kinetic structure of behavioral repertoires

PubMed Central

Thompson, Travis; Lubinski, David

1986-01-01

It is suggested that molar streams of behavior are constructed of various arrangements of three elementary constituents (elicited, evoked, and emitted response classes). An eight-cell taxonomy is elaborated as a framework for analyzing and synthesizing complex behavioral repertoires based on these functional units. It is proposed that the local force binding functional units into a smoothly articulated kinetic sequence arises from temporally arranged relative response probability relationships. Behavioral integration is thought to reflect the joint influence of the organism's hierarchy of relative response probabilities, fluctuating biological states, and the arrangement of environmental and behavioral events in time. PMID:16812461

Chromosomes and plant cell division in space

NASA Technical Reports Server (NTRS)

Krikorian, A. D.

1988-01-01

The objectives were: examination of chromosomal aberrations; development of an experimental system; and engineering design units (EDUs) evaluation. Evaluation criteria are presented. Procedures were developed for shuttle-based investigations which result in the procurement of plant root tips for subsequent cytological examination.

Map of assessed shale gas in the United States, 2012

USGS Publications Warehouse

,; Biewick, Laura R. H.

2013-01-01

The U.S. Geological Survey has compiled a map of shale-gas assessments in the United States that were completed by 2012 as part of the National Assessment of Oil and Gas Project. Using a geology-based assessment methodology, the U.S. Geological Survey quantitatively estimated potential volumes of undiscovered gas within shale-gas assessment units. These shale-gas assessment units are mapped, and square-mile cells are shown to represent proprietary shale-gas wells. The square-mile cells include gas-producing wells from shale intervals. In some cases, shale-gas formations contain gas in deeper parts of a basin and oil at shallower depths (for example, the Woodford Shale and the Eagle Ford Shale). Because a discussion of shale oil is beyond the scope of this report, only shale-gas assessment units and cells are shown. The map can be printed as a hardcopy map or downloaded for interactive analysis in a Geographic Information System data package using the ArcGIS map document (file extension MXD) and published map file (file extension PMF). Also available is a publications access table with hyperlinks to current U.S. Geological Survey shale gas assessment publications and web pages. Assessment results and geologic reports are available as completed at the U.S. Geological Survey Energy Resources Program Web Site, http://energy.usgs.gov/OilGas/AssessmentsData/NationalOilGasAssessment.aspx. A historical perspective of shale gas activity in the United States is documented and presented in a video clip included as a PowerPoint slideshow.

Diesel fuel to dc power: Navy & Marine Corps Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bloomfield, D.P.

1996-12-31

During the past year Analytic Power has tested fuel cell stacks and diesel fuel processors for US Navy and Marine Corps applications. The units are 10 kW demonstration power plants. The USN power plant was built to demonstrate the feasibility of diesel fueled PEM fuel cell power plants for 250 kW and 2.5 MW shipboard power systems. We designed and tested a ten cell, 1 kW USMC substack and fuel processor. The complete 10 kW prototype power plant, which has application to both power and hydrogen generation, is now under construction. The USN and USMC fuel cell stacks have beenmore » tested on both actual and simulated reformate. Analytic Power has accumulated operating experience with autothermal reforming based fuel processors operating on sulfur bearing diesel fuel, jet fuel, propane and natural gas. We have also completed the design and fabrication of an advanced regenerative ATR for the USMC. One of the significant problems with small fuel processors is heat loss which limits its ability to operate with the high steam to carbon ratios required for coke free high efficiency operation. The new USMC unit specifically addresses these heat transfer issues. The advances in the mill programs have been incorporated into Analytic Power`s commercial units which are now under test.« less

The Vertebrate Brain, Evidence of Its Modular Organization and Operating System: Insights into the Brain's Basic Units of Structure, Function, and Operation and How They Influence Neuronal Signaling and Behavior.

PubMed

Baslow, Morris H

2011-01-01

The human brain is a complex organ made up of neurons and several other cell types, and whose role is processing information for use in eliciting behaviors. However, the composition of its repeating cellular units for both structure and function are unresolved. Based on recent descriptions of the brain's physiological "operating system", a function of the tri-cellular metabolism of N-acetylaspartate (NAA) and N-acetylaspartylglutamate (NAAG) for supply of energy, and on the nature of "neuronal words and languages" for intercellular communication, insights into the brain's modular structural and functional units have been gained. In this article, it is proposed that the basic structural unit in brain is defined by its physiological operating system, and that it consists of a single neuron, and one or more astrocytes, oligodendrocytes, and vascular system endothelial cells. It is also proposed that the basic functional unit in the brain is defined by how neurons communicate, and consists of two neurons and their interconnecting dendritic-synaptic-dendritic field. Since a functional unit is composed of two neurons, it requires two structural units to form a functional unit. Thus, the brain can be envisioned as being made up of the three-dimensional stacking and intertwining of myriad structural units which results not only in its gross structure, but also in producing a uniform distribution of binary functional units. Since the physiological NAA-NAAG operating system for supply of energy is repeated in every structural unit, it is positioned to control global brain function.

A portable cell-based optical detection device for rapid detection of Listeria and Bacillus toxins

NASA Astrophysics Data System (ADS)

Banerjee, Pratik; Banada, Padmapriya P.; Rickus, Jenna L.; Morgan, Mark T.; Bhunia, Arun K.

2005-11-01

A mammalian cell-based optical biosensor was built to detect pathogenic Listeria and Bacillus species. This sensor measures the ability of the pathogens to infect and induce cytotoxicity on hybrid lymphocyte cell line (Ped-2E9) resulting in the release of alkaline phosphatase (ALP) that can be detected optically using a portable spectrophotometer. The Ped-2E9 cells were encapsulated in collagen gel matrices and grown in 48-well plates or in specially designed filtration tube units. Toxin preparations or bacterial cells were introduced and ALP release was assayed after 3-5 h. Pathogenic L. monocytogenes strains or the listeriolysin toxins preparation showed cytotoxicity ranging from 55% - 92%. Toxin preparations (~20 μg/ml) from B. cereus strains showed 24 - 98% cytotoxicity. In contrast, a non-pathogenic L. innocua (F4247) and a B. substilis induced only 2% and 8% cytotoxicity, respectively. This cell-based detection device demonstrates its ability to detect the presence of pathogenic Listeria and Bacillus species and can potentially be used onsite for food safety or in biosecurity application.

Heptagraphene: Tunable dirac cones in a graphitic structure

DOE PAGES

Lopez-Bezanilla, Alejandro; Martin, Ivar; Littlewood, Peter B.

2016-09-13

Here, we predict the existence and dynamical stability of heptagraphene, a new graphitic structure formed of rings of 10 carbon atoms bridged by carbene groups yielding seven-membered rings. Despite the rectangular unit cell, the band structure is topologically equivalent to that of strongly distorted graphene. Density-functional-theory calculations demonstrate that heptagraphene has Dirac cones on symmetry lines that are robust against biaxial strain but which open a gap under shear. At high deformation values bond reconstructions lead to different electronic band arrangements in dynamically stable configurations. Within a tight-binding framework this richness of the electronic behavior is identified as a directmore » consequence of the symmetry breaking within the cell which, unlike other graphitic structures, leads to band gap opening. A combined approach of chemical and physical modification of graphene unit cell unfurls the opportunity to design carbon-based systems in which one aims to tune an electronic band gap.« less

Engineering aspects and hardware verification of a volume producable solid oxide fuel cell stack design for diesel auxiliary power units

NASA Astrophysics Data System (ADS)

Stelter, Michael; Reinert, Andreas; Mai, Björn Erik; Kuznecov, Mihail

A solid oxide fuel cell (SOFC) stack module is presented that is designed for operation on diesel reformate in an auxiliary power unit (APU). The stack was designed using a top-down approach, based on a specification of an APU system that is installed on board of vehicles. The stack design is planar, modular and scalable with stamped sheet metal interconnectors. It features thin membrane electrode assemblies (MEAs), such as electrolyte supported cells (ESC) and operates at elevated temperatures around 800 °C. The stack has a low pressure drop in both the anode and the cathode to facilitate a simple system layout. An overview of the technical targets met so far is given. A stack power density of 0.2 kW l -1 has been demonstrated in a fully integrated, thermally self-sustaining APU prototype running with diesel and without an external water supply.

Molecular dynamics simulations of polarizable DNA in crystal environment

NASA Astrophysics Data System (ADS)

Babin, Volodymyr; Baucom, Jason; Darden, Thomas A.; Sagui, Celeste

We have investigated the role of the electrostatic description and cell environment in molecular dynamics (MD) simulations of DNA. Multiple unrestrained MD simulations of the DNA duplex d(CCAACGTTGG)2 have been carried out using two different force fields: a traditional description based on atomic point charges and a polarizable force field. For the time scales probed, and given the ?right? distribution of divalent ions, the latter performs better than the nonpolarizable force field. In particular, by imposing the experimental unit cell environment, an initial configuration with ideal B-DNA duplexes in the unit cell acquires sequence-dependent features that very closely resemble the crystallographic ones. Simultaneously, the all-atom root-mean-square coordinates deviation (RMSD) with respect to the crystallographic structure is seen to decay. At later times, the polarizable force field is able to maintain this lower RMSD, while the nonpolarizable force field starts to drift away.

Designed cell consortia as fragrance-programmable analog-to-digital converters.

PubMed

Müller, Marius; Ausländer, Simon; Spinnler, Andrea; Ausländer, David; Sikorski, Julian; Folcher, Marc; Fussenegger, Martin

2017-03-01

Synthetic biology advances the rational engineering of mammalian cells to achieve cell-based therapy goals. Synthetic gene networks have nearly reached the complexity of digital electronic circuits and enable single cells to perform programmable arithmetic calculations or to provide dynamic remote control of transgenes through electromagnetic waves. We designed a synthetic multilayered gaseous-fragrance-programmable analog-to-digital converter (ADC) allowing for remote control of digital gene expression with 2-bit AND-, OR- and NOR-gate logic in synchronized cell consortia. The ADC consists of multiple sampling-and-quantization modules sensing analog gaseous fragrance inputs; a gas-to-liquid transducer converting fragrance intensity into diffusible cell-to-cell signaling compounds; a digitization unit with a genetic amplifier circuit to improve the signal-to-noise ratio; and recombinase-based digital expression switches enabling 2-bit processing of logic gates. Synthetic ADCs that can remotely control cellular activities with digital precision may enable the development of novel biosensors and may provide bioelectronic interfaces synchronizing analog metabolic pathways with digital electronics.

Unit Cells

ERIC Educational Resources Information Center

Olsen, Robert C.; Tobiason, Fred L.

1975-01-01

Describes the construction of unit cells using clear plastic cubes which can be disassembled, and one inch cork balls of various colors, which can be cut in halves, quarters, or eighths, and glued on the inside face of the cube, thus simulating a unit cell. (MLH)

Monopolar fuel cell stack coupled together without use of top or bottom cover plates or tie rods

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram R. (Inventor); Valdez, Thomas I. (Inventor)

2009-01-01

A monopolar fuel cell stack comprises a plurality of sealed unit cells coupled together. Each unit cell comprises two outer cathodes adjacent to corresponding membrane electrode assemblies and a center anode plate. An inlet and outlet manifold are coupled to the anode plate and communicate with a channel therein. Fuel flows from the inlet manifold through the channel in contact with the anode plate and flows out through the outlet manifold. The inlet and outlet manifolds are arranged to couple to the inlet and outlet manifolds respectively of an adjacent one of the plurality of unit cells to permit fuel flow in common into all of the inlet manifolds of the plurality of the unit cells when coupled together in a stack and out of all of the outlet manifolds of the plurality of unit cells when coupled together in a stack.

Crystallization and preliminary X-ray diffraction studies of Seneca Valley Virus-001, a new member of the Picornaviridae family

DOE Office of Scientific and Technical Information (OSTI.GOV)

Venkataraman, Sangita; Reddy, Seshidhar P.; Loo, Jackie

2008-04-01

Seneca Valley Virus-001 of the Picornavirdae family was crystallized in the space group R3 and X-ray diffraction data was collected to a resolution of 2.3 Å. Rotation-function studies suggested the presence of two distict sets of 20 protomers that belong to two different virus particles in the crystallographic asymmetric unit. Seneca Valley Virus-001 (SVV-001) is a newly found species in the Picornaviridae family. SVV-001 is the first naturally occurring nonpathogenic picorna@@virus observed to mediate selective cytotoxicity towards tumor cells with neuroendocrine cancer features. The nonsegmented (+)ssRNA genome of SVV-001 shares closest sequence similarity to the genomes of the members ofmore » the Cardiovirus genus. However, based on the distinct characteristics of the genome organization and other biochemical properties, it has been suggested that SVV-001 represents a new genus, namely ‘Senecavirus’, in the Picornaviridae family. In order to understand the oncolytic properties of SVV-001, the native virus was crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to space group R3, with unit-cell parameters (in the hexagonal setting) a = b = 311.5, c = 1526.4 Å. Although the SVV crystals diffracted to better than 2.3 Å resolution, the data quality is acceptable [I/σ(I) > 2.0] to 2.6 Å resolution. The unit-cell volume and the locked rotation-function analysis suggest that six particles could be accommodated in the unit cell, with two distinct sets of one third of a particle, each containing 20 protomers, occupying the crystallographic asymmetric unit.« less

Small-Molecule Acceptor Based on the Heptacyclic Benzodi(cyclopentadithiophene) Unit for Highly Efficient Nonfullerene Organic Solar Cells.

PubMed

Kan, Bin; Feng, Huanran; Wan, Xiangjian; Liu, Feng; Ke, Xin; Wang, Yanbo; Wang, Yunchuang; Zhang, Hongtao; Li, Chenxi; Hou, Jianhui; Chen, Yongsheng

2017-04-05

A new nonfullerene small molecule with acceptor-donor-acceptor (A-D-A) structure, namely, NFBDT, based on a heptacyclic benzodi(cyclopentadithiophene) (FBDT) unit using benzo[1,2-b:4,5-b']dithiophene as the core unit, was designed and synthesized. Its absorption ability, energy levels, thermal stability, as well as photovoltaic performances were fully investigated. NFBDT exhibits a low optical bandgap of 1.56 eV resulting in wide and efficient absorption that covered the range from 600 to 800 nm, and suitable energy levels as an electron acceptor. With the widely used and successful wide bandgap polymer PBDB-T selected as the electron donor material, an optimized PCE of 10.42% was obtained for the PBDB-T:NFBDT-based device with an outstanding short-circuit current density of 17.85 mA cm -2 under AM 1.5G irradiation (100 mW cm -2 ), which is so far among the highest performance of NF-OSC devices. These results demonstrate that the BDT unit could also be applied for designing NF-acceptors, and the fused-ring benzodi(cyclopentadithiophene) unit is a prospective block for designing new NF-acceptors with excellent performance.

On-site fuel cell field test support program

NASA Astrophysics Data System (ADS)

Staniunas, J. W.; Merten, G. P.

1982-01-01

In order to assess the impact of grid connection on the potential market for fuel cell service, applications studies were conducted to identify the fuel cell operating modes and corresponding fuel cell sizing criteria which offer the most potential for initial commercial service. The market for grid-connected fuel cell service was quantified using United's market analysis program and computerized building data base. Electric and gas consumption data for 268 buildings was added to our surveyed building data file, bringing the total to 407 buildings. These buildings were analyzed for grid-isolated and grid-connected fuel cell service. The results of the analyses indicated that the nursing home, restaurant and health club building sectors offer significant potential for fuel cell service.

Cytoplasmic connection of sperm cells to the pollen vegetative cell nucleus: potential roles of the male germ unit revisited.

PubMed

McCue, Andrea D; Cresti, Mauro; Feijó, José A; Slotkin, R Keith

2011-03-01

The male germ cells of angiosperm plants are neither free-living nor flagellated and therefore are dependent on the unique structure of the pollen grain for fertilization. During angiosperm male gametogenesis, an asymmetric mitotic division produces the generative cell, which is completely enclosed within the cytoplasm of the larger pollen grain vegetative cell. Mitotic division of the generative cell generates two sperm cells that remain connected by a common extracellular matrix with potential intercellular connections. In addition, one sperm cell has a cytoplasmic projection in contact with the vegetative cell nucleus. The shared extracellular matrix of the two sperm cells and the physical association of one sperm cell to the vegetative cell nucleus forms a linkage of all the genetic material in the pollen grain, termed the male germ unit. Found in species representing both the monocot and eudicot lineages, the cytoplasmic projection is formed by vesicle formation and microtubule elongation shortly after the formation of the generative cell and tethers the male germ unit until just prior to fertilization. The cytoplasmic projection plays a structural role in linking the male germ unit, but potentially plays other important roles. Recently, it has been speculated that the cytoplasmic projection and the male germ unit may facilitate communication between the somatic vegetative cell nucleus and the germinal sperm cells, via RNA and/or protein transport. This review focuses on the nature of the sperm cell cytoplasmic projection and the potential communicative function of the male germ unit.

Biophysically Based Mathematical Modeling of Interstitial Cells of Cajal Slow Wave Activity Generated from a Discrete Unitary Potential Basis

PubMed Central

Faville, R.A.; Pullan, A.J.; Sanders, K.M.; Koh, S.D.; Lloyd, C.M.; Smith, N.P.

2009-01-01

Abstract Spontaneously rhythmic pacemaker activity produced by interstitial cells of Cajal (ICC) is the result of the entrainment of unitary potential depolarizations generated at intracellular sites termed pacemaker units. In this study, we present a mathematical modeling framework that quantitatively represents the transmembrane ion flows and intracellular Ca2+ dynamics from a single ICC operating over the physiological membrane potential range. The mathematical model presented here extends our recently developed biophysically based pacemaker unit modeling framework by including mechanisms necessary for coordinating unitary potential events, such as a T-Type Ca2+ current, Vm-dependent K+ currents, and global Ca2+ diffusion. Model simulations produce spontaneously rhythmic slow wave depolarizations with an amplitude of 65 mV at a frequency of 17.4 cpm. Our model predicts that activity at the spatial scale of the pacemaker unit is fundamental for ICC slow wave generation, and Ca2+ influx from activation of the T-Type Ca2+ current is required for unitary potential entrainment. These results suggest that intracellular Ca2+ levels, particularly in the region local to the mitochondria and endoplasmic reticulum, significantly influence pacing frequency and synchronization of pacemaker unit discharge. Moreover, numerical investigations show that our ICC model is capable of qualitatively replicating a wide range of experimental observations. PMID:19527643

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

NASA Technical Reports Server (NTRS)

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.

An Object-Independent ENZ Metamaterial-Based Wideband Electromagnetic Cloak

PubMed Central

Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2016-01-01

A new, metamaterial-based electromagnetic cloaking operation is proposed in this study. The metamaterial exhibits a sharp transmittance in the C-band of the microwave spectrum with negative effective property of permittivity at that frequency. Two metal arms were placed on an FR-4 substrate to construct a double-split-square shape structure. The size of the resonator was maintained to achieve the effective medium property of the metamaterial. Full wave numerical simulation was performed to extract the reflection and transmission coefficients for the unit cell. Later on, a single layer square-shaped cloak was designed using the proposed metamaterial unit cell. The cloak hides a metal cylinder electromagnetically, where the material exhibits epsilon-near-zero (ENZ) property. Cloaking operation was demonstrated adopting the scattering-reduction technique. The measured result was provided to validate the characteristics of the metamaterial and the cloak. Some object size- and shape-based analyses were performed with the cloak, and a common cloaking region was revealed over more than 900 MHz in the C-band for the different objects. PMID:27634456

An Object-Independent ENZ Metamaterial-Based Wideband Electromagnetic Cloak.

PubMed

Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2016-09-16

A new, metamaterial-based electromagnetic cloaking operation is proposed in this study. The metamaterial exhibits a sharp transmittance in the C-band of the microwave spectrum with negative effective property of permittivity at that frequency. Two metal arms were placed on an FR-4 substrate to construct a double-split-square shape structure. The size of the resonator was maintained to achieve the effective medium property of the metamaterial. Full wave numerical simulation was performed to extract the reflection and transmission coefficients for the unit cell. Later on, a single layer square-shaped cloak was designed using the proposed metamaterial unit cell. The cloak hides a metal cylinder electromagnetically, where the material exhibits epsilon-near-zero (ENZ) property. Cloaking operation was demonstrated adopting the scattering-reduction technique. The measured result was provided to validate the characteristics of the metamaterial and the cloak. Some object size- and shape-based analyses were performed with the cloak, and a common cloaking region was revealed over more than 900 MHz in the C-band for the different objects.

Ceramic matrix composite behavior -- Computational simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chamis, C.C.; Murthy, P.L.N.; Mital, S.K.

Development of analytical modeling and computational capabilities for the prediction of high temperature ceramic matrix composite behavior has been an ongoing research activity at NASA-Lewis Research Center. These research activities have resulted in the development of micromechanics based methodologies to evaluate different aspects of ceramic matrix composite behavior. The basis of the approach is micromechanics together with a unique fiber substructuring concept. In this new concept the conventional unit cell (the smallest representative volume element of the composite) of micromechanics approach has been modified by substructuring the unit cell into several slices and developing the micromechanics based equations at themore » slice level. Main advantage of this technique is that it can provide a much greater detail in the response of composite behavior as compared to a conventional micromechanics based analysis and still maintains a very high computational efficiency. This methodology has recently been extended to model plain weave ceramic composites. The objective of the present paper is to describe the important features of the modeling and simulation and illustrate with select examples of laminated as well as woven composites.« less

Phenothiazine-based small-molecule organic solar cells with power conversion efficiency over 7% and open circuit voltage of about 1.0 V using solvent vapor annealing.

PubMed

Rout, Yogajivan; Misra, Rajneesh; Singhal, Rahul; Biswas, Subhayan; Sharma, Ganesh D

2018-02-28

We have used two unsymmetrical small molecules, named phenothiazine 1 and 2 with a D-A-D-π-D configuration, where phenothiazine is used as a central unit, triphenylamine is used as a terminal unit and TCBD and cyclohexa-2,5-diene-1,4-diylidene-expanded TCBD are used as an acceptor between the phenothiazine and triphenylamine units, as a small molecule donor along with PC 71 BM as an acceptor for solution processed bulk heterojunction solar cells. The variation of acceptors in the phenothiazine derivatives makes an exciting change in the photophysical and electrochemical properties, hole mobility and therefore photovoltaic performance. The optimized device based on phenothiazine 2 exhibited a high power conversion efficiency of 7.35% (J sc = 11.98 mA cm -2 , V oc = 0.99 V and FF = 0.62), while the device based on phenothiazine 1 showed a low PCE of 4.81% (J sc = 8.73 mA cm -2 , V oc = 0.95 V and FF = 0.58) after solvent vapour annealing (SVA) treatment. The higher value of power conversion efficiency of the 2 based devices irrespective of the processing conditions may be related to the broader absorption and lower band gap of 2 as compared to 1. The improvement in the SVA treated active layer may be related to the enhanced crystallinity, molecular ordering and aggregation and shorter π-π stacking distance of the small molecule donors.

Design of all-optical memory cell using EIT and lasing without inversion phenomena in optical micro ring resonators

NASA Astrophysics Data System (ADS)

Pasyar, N.; Yadipour, R.; Baghban, H.

2017-07-01

The proposed design of the optical memory unit cell contains dual micro ring resonators in which the effect of lasing without inversion (LWI) in three-level nano particles doped over the optical resonators or integrators as the gain segment is used for loss compensation. Also, an on/off phase shifter based on electromagnetically induced transparency (EIT) in three-level quantum dots (QDs) has been used for data reading at requested time. Device minimizing for integrated purposes and high speed data storage are the main advantages of the optical integrator based memory.

Hydrogen Fuel Cell Performance as Telecommunications Backup Power in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, Jennifer; Saur, Genevieve; Sprik, Sam

2015-03-01

Working in collaboration with the U.S. Department of Energy (DOE) and industry project partners, the National Renewable Energy Laboratory (NREL) acts as the central data repository for the data collected from real-world operation of fuel cell backup power systems. With American Recovery and Reinvestment Act of 2009 (ARRA) co-funding awarded through DOE's Fuel Cell Technologies Office, more than 1,300 fuel cell units were deployed over a three-plus-year period in stationary, material handling equipment, auxiliary power, and backup power applications. This surpassed a Fuel Cell Technologies Office ARRA objective to spur commercialization of an early market technology by installing 1,000 fuelmore » cell units across several different applications, including backup power. By December 2013, 852 backup power units out of 1,330 fuel cell units deployed were providing backup service, mainly for telecommunications towers. For 136 of the fuel cell backup units, project participants provided detailed operational data to the National Fuel Cell Technology Evaluation Center for analysis by NREL's technology validation team. NREL analyzed operational data collected from these government co-funded demonstration projects to characterize key fuel cell backup power performance metrics, including reliability and operation trends, and to highlight the business case for using fuel cells in these early market applications. NREL's analyses include these critical metrics, along with deployment, U.S. grid outage statistics, and infrastructure operation.« less

Importance of Unit Cells in Accurate Evaluation of the Characteristics of Graphene

NASA Astrophysics Data System (ADS)

Sabzyan, Hassan; Sadeghpour, Narges

2016-04-01

Effects of the size of the unit cell on energy, atomic charges, and phonon frequencies of graphene at the Γ point of the Brillouin zone are studied in the absence and presence of an electric field using density functional theory (DFT) methods (LDA and DFT-PBE functionals with Goedecker-Teter-Hutter (GTH) and Troullier-Martins (TM) norm-conserving pseudopotentials). Two types of unit cells containing nC=4-28 carbon atoms are considered. Results show that stability of graphene increases with increasing size of the unit cell. Energy, atomic charges, and phonon frequencies all converge above nC=24 for all functional-pseudopotentials used. Except for the LDA-GTH calculations, application of an electric field of 0.4 and 0.9 V/nm strengths does not change the trends with the size of the unit cell but instead slightly decreases the binding energy of graphene. Results of this study show that the choice of unit cell size and type is critical for calculation of reliable characteristics of graphene.

Wide bandgap OPV polymers based on pyridinonedithiophene unit with efficiency >5%

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schneider, Alexander M.; Lu, Luyao; Manley, Eric F.

2015-06-04

We report the properties of a new series of wide band gap photovoltaic polymers based on the N-alkyl 2-pyridone dithiophene (PDT) unit. These polymers are effective bulk heterojunction solar cell materials when blended with phenyl-C 71-butyric acid methyl ester (PC 71BM). They achieve power conversion efficiencies (up to 5.33%) high for polymers having such large bandgaps, ca. 2.0 eV (optical) and 2.5 eV (electrochemical). As a result, grazing incidence wide-angle X-ray scattering (GIWAXS) reveals strong correlations between π–π stacking distance and regularity, polymer backbone planarity, optical absorption maximum energy, and photovoltaic efficiency.

Associative list processing unit

DOEpatents

Hemmert, Karl Scott; Underwood, Keith D.

2013-01-29

An associative list processing unit and method comprising employing a plurality of prioritized cell blocks and permitting inserts to occur in a single clock cycle if all of the cell blocks are not full. Also, an associative list processing unit and method comprising employing a plurality of prioritized cell blocks and using a tree of prioritized multiplexers descending from the plurality of cell blocks.

The Royan Public Umbilical Cord Blood Bank: Does It Cover All Ethnic Groups in Iran Based on HLA Diversity?

PubMed

Ebrahimkhani, Saeideh; Farjadian, Shirin; Ebrahimi, Marzieh

2014-04-01

Umbilical cord blood (UCB) stem cells allow the transplantation of partially human leukocyte antigen (HLA)-matched grafts and are a valuable resource for the treatment of hematologic malignancies and heritable hematologic, immunologic and metabolic diseases, especially when a compatible bone marrow donor is unavailable. The aim of this study was to determine how many ethnic groups in Iran are covered by the available UCB units based on HLA diversity. From 2009 until mid-2013, 4,981 (30.3%) of the 16,437 UCB samples collected met the storage criteria and were cryopreserved at a public cord blood bank (CBB) in Tehran, Iran. HLA-A, -B and -DRB1 were typed in 1,793 samples. The mean volume of the cryopreserved samples was 81.25 ± 20.3 ml. The range of total nucleated cells per unit was 51 × 10(7)-107 × 10(7). The most common HLA alleles were HLA-A*2 (17%) and HLA-A*24 (15.6%), HLA-B*35 (16.8%) and HLA-B*51 (13.9%), and HLA-DRB1*11 (20%) and HLA-DRB1*15 (14%). The predominant haplotypes were HLA-A*24-B*35-DRB1*11 (2%), HLA-A*02-B*50-DR*07 (1.8%), and HLA-A*02-B*51-DRB1*11 (1.5%). Based on the HLA-DRB1 profiles, the UCB units available at the Royan public UCB bank are a potentially adequate resource for hematopoietic stem cell transplantation for Iranian recipients belonging to particular ethnic groups. Regular educational programs to improve the public knowledge of UCB for transplantation can enhance the public CBB stocks for all Iranian ethnic groups in the future.

Red blood cell storage time and transfusion: current practice, concerns and future perspectives

PubMed Central

García-Roa, María; del Carmen Vicente-Ayuso, María; Bobes, Alejandro M.; Pedraza, Alexandra C.; González-Fernández, Ataúlfo; Martín, María Paz; Sáez, Isabel; Seghatchian, Jerard; Gutiérrez, Laura

2017-01-01

Red blood cells (RBCs) units are the most requested transfusion product worldwide. Indications for transfusion include symptomatic anaemia, acute sickle cell crisis, and acute blood loss of more than 30% of the blood volume, with the aim of restoring tissue oxygen delivery. However, stored RBCs from donors are not a qualitative equal product, and, in many ways, this is a matter of concern in the transfusion practice. Besides donor-to-donor variation, the storage time influences the RBC unit at the qualitative level, as RBCs age in the storage bag and are exposed to the so-called storage lesion. Several studies have shown that the storage lesion leads to post-transfusion enhanced clearance, plasma transferrin saturation, nitric oxide scavenging and/or immunomodulation with potential unwanted transfusion-related clinical outcomes, such as acute lung injury or higher mortality rate. While, to date, several studies have claimed the risk or deleterious effects of “old” vs “young” RBC transfusion regimes, it is still a matter of debate, and consideration should be taken of the clinical context. Transfusion-dependent patients may benefit from transfusion with “young” RBC units, as it assures longer inter-transfusion periods, while transfusion with “old” RBC units is not itself harmful. Unbiased Omics approaches are being applied to the characterisation of RBC through storage, to better understand the (patho)physiological role of microparticles (MPs) that are found naturally, and also on stored RBC units. Perhaps RBC storage time is not an accurate surrogate for RBC quality and there is a need to establish which parameters do indeed reflect optimal efficacy and safety. A better Omics characterisation of components of “young” and “old” RBC units, including MPs, donor and recipient, might lead to the development of new therapies, including the use of engineered RBCs or MPs as cell-based drug delivering tools, or cost-effective personalised transfusion strategies. PMID:28518049

A Simple BODIPY-Based Viscosity Probe for Imaging of Cellular Viscosity in Live Cells

PubMed Central

Su, Dongdong; Teoh, Chai Lean; Gao, Nengyue; Xu, Qing-Hua; Chang, Young-Tae

2016-01-01

Intracellular viscosity is a fundamental physical parameter that indicates the functioning of cells. In this work, we developed a simple boron-dipyrromethene (BODIPY)-based probe, BTV, for cellular mitochondria viscosity imaging by coupling a simple BODIPY rotor with a mitochondria-targeting unit. The BTV exhibited a significant fluorescence intensity enhancement of more than 100-fold as the solvent viscosity increased. Also, the probe showed a direct linear relationship between the fluorescence lifetime and the media viscosity, which makes it possible to trace the change of the medium viscosity. Furthermore, it was demonstrated that BTV could achieve practical applicability in the monitoring of mitochondrial viscosity changes in live cells through fluorescence lifetime imaging microscopy (FLIM). PMID:27589762

A Simple BODIPY-Based Viscosity Probe for Imaging of Cellular Viscosity in Live Cells.

PubMed

Su, Dongdong; Teoh, Chai Lean; Gao, Nengyue; Xu, Qing-Hua; Chang, Young-Tae

2016-08-31

Intracellular viscosity is a fundamental physical parameter that indicates the functioning of cells. In this work, we developed a simple boron-dipyrromethene (BODIPY)-based probe, BTV, for cellular mitochondria viscosity imaging by coupling a simple BODIPY rotor with a mitochondria-targeting unit. The BTV exhibited a significant fluorescence intensity enhancement of more than 100-fold as the solvent viscosity increased. Also, the probe showed a direct linear relationship between the fluorescence lifetime and the media viscosity, which makes it possible to trace the change of the medium viscosity. Furthermore, it was demonstrated that BTV could achieve practical applicability in the monitoring of mitochondrial viscosity changes in live cells through fluorescence lifetime imaging microscopy (FLIM).

Experimental evaluation of battery cells for space-based radar application

NASA Technical Reports Server (NTRS)

Maskell, Craig A.; Metcalfe, John R.

1994-01-01

A test program was conducted to characterize five space-quality nickel-hydrogen (NiH2) battery cells. A subset of those tests was also done on five commercial nickel-cadmium (NiCd) cells, for correlation to the characteristics of an Energy Storage Unit Simulator. The test program implemented the recommendations of a 1991 study, as reported to IECEC-92. The findings of the tests are summarized, and expected impacts on the performance of the electrical power system (EPS) of a large space-based radar (SBR) surveillance satellite are derived. The main characteristics examined and compared were terminal voltage (average and transient) and capacity through discharge, equivalent series resistance, derived inductance and capacitance, charge return efficiency, and inter-pulse charge effectiveness.

10. Credit USAF, 7 September 1945. Original housed in the ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. Credit USAF, 7 September 1945. Original housed in the Muroc Flight Test Base, Unit History, 1 September 1942 - 30 June 1945. Alfred F. Simpson Historical Research Agency. United States Air Force. Maxwell AFB, Alabama. View looks northwest into jet engine test cell located on aircraft apron southeast of Building 4305. In background of photo can be seen doors of Unicon Portable Hangar on left, and southeast end of Building T-l Bachelor Officers' Quarters ("Desert Rat Hotel"). This view emphasizes the hangar's role as a test facility for developing and testing aircraft and aircraft systems, not simply as a "garage" for aircraft. - Edwards Air Force Base, North Base, Unicon Portable Hangar, First & C Streets, Boron, Kern County, CA

Empirical Derivation of Correction Factors for Human Spiral Ganglion Cell Nucleus and Nucleolus Count Units.

PubMed

Robert, Mark E; Linthicum, Fred H

2016-01-01

Profile count method for estimating cell number in sectioned tissue applies a correction factor for double count (resulting from transection during sectioning) of count units selected to represent the cell. For human spiral ganglion cell counts, we attempted to address apparent confusion between published correction factors for nucleus and nucleolus count units that are identical despite the role of count unit diameter in a commonly used correction factor formula. We examined a portion of human cochlea to empirically derive correction factors for the 2 count units, using 3-dimensional reconstruction software to identify double counts. The Neurotology and House Histological Temporal Bone Laboratory at University of California at Los Angeles. Using a fully sectioned and stained human temporal bone, we identified and generated digital images of sections of the modiolar region of the lower first turn of cochlea, identified count units with a light microscope, labeled them on corresponding digital sections, and used 3-dimensional reconstruction software to identify double-counted count units. For 25 consecutive sections, we determined that double-count correction factors for nucleus count unit (0.91) and nucleolus count unit (0.92) matched the published factors. We discovered that nuclei and, therefore, spiral ganglion cells were undercounted by 6.3% when using nucleolus count units. We determined that correction factors for count units must include an element for undercounting spiral ganglion cells as well as the double-count element. We recommend a correction factor of 0.91 for the nucleus count unit and 0.98 for the nucleolus count unit when using 20-µm sections. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

Comparison of Multiscale Method of Cells-Based Models for Predicting Elastic Properties of Filament Wound C/C-SiC

NASA Technical Reports Server (NTRS)

Pineda, Evan J.; Fassin, Marek; Bednarcyk, Brett A.; Reese, Stefanie; Simon, Jaan-Willem

2017-01-01

Three different multiscale models, based on the method of cells (generalized and high fidelity) micromechanics models were developed and used to predict the elastic properties of C/C-SiC composites. In particular, the following multiscale modeling strategies were employed: Concurrent multiscale modeling of all phases using the generalized method of cells, synergistic (two-way coupling in space) multiscale modeling with the generalized method of cells, and hierarchical (one-way coupling in space) multiscale modeling with the high fidelity generalized method of cells. The three models are validated against data from a hierarchical multiscale finite element model in the literature for a repeating unit cell of C/C-SiC. Furthermore, the multiscale models are used in conjunction with classical lamination theory to predict the stiffness of C/C-SiC plates manufactured via a wet filament winding and liquid silicon infiltration process recently developed by the German Aerospace Institute.

A Unit Cell Laboratory Experiment: Marbles, Magnets, and Stacking Arrangements

ERIC Educational Resources Information Center

Collins, David C.

2011-01-01

An undergraduate first-semester general chemistry laboratory experiment introducing face-centered, body-centered, and simple cubic unit cells is presented. Emphasis is placed on the stacking arrangement of solid spheres used to produce a particular unit cell. Marbles and spherical magnets are employed to prepare each stacking arrangement. Packing…

NMR study of methane + ethane structure I hydrate decomposition.

PubMed

Dec, Steven F; Bowler, Kristen E; Stadterman, Laura L; Koh, Carolyn A; Sloan, E Dendy

2007-05-24

The thermally activated decomposition of methane + ethane structure I hydrate was studied with use of 13C magic-angle spinning (MAS) NMR as a function of composition and temperature. The observed higher decomposition rate of large sI cages initially filled with ethane gas can be described in terms of a model where a distribution of sI unit cells exists such that a particular unit cell contains zero, one, or two methane molecules in the unit cell; this distribution of unit cells is combined to form the observed equilibrium composition. In this model, unit cells with zero methane molecules are the least stable and decompose more rapidly than those populated with one or two methane molecules leading to the observed overall faster decomposition rate of the large cages containing ethane molecules.

Cost-effectiveness of pazopanib versus sunitinib for metastatic renal cell carcinoma in the United Kingdom

PubMed Central

Amdahl, Jordan; Diaz, Jose; Sharma, Arati; Park, Jinhee; Chandiwana, David

2017-01-01

Background Sunitinib and pazopanib are the only two targeted therapies for the first-line treatment of locally advanced or metastatic renal cell carcinoma (mRCC) recommended by the United Kingdom’s National Institute for Health and Care Excellence. Pazopanib demonstrated non-inferior efficacy and a differentiated safety profile versus sunitinib in the phase III COMPARZ trial. The current analysis provides a direct comparison of the cost-effectiveness of pazopanib versus sunitinib from the perspective of the United Kingdom’s National Health Service based on data from COMPARZ and other sources. Methods A partitioned-survival analysis model with three health states (alive with no progression, alive with progression, or dead) was used to estimate the incremental cost per quality-adjusted life-year (QALY) gained for pazopanib versus sunitinib over five years (duration of follow-up for final survival analysis in COMPARZ). The proportion of patients in each health state over time was based on Kaplan–Meier distributions for progression-free and overall survival from COMPARZ. Utility values were based on EQ-5D data from the pivotal study of pazopanib versus placebo. Costs were based on medical resource utilisation data from COMPARZ and unit costs from secondary sources. Probabilistic and deterministic sensitivity analyses were conducted to assess uncertainty of model results. Results In the base case, pazopanib was estimated to provide more QALYs (0.0565, 95% credible interval [CrI]: −0.0920 to 0.2126) at a lower cost (−£1,061, 95% CrI: −£4,328 to £2,067) versus sunitinib. The probability that pazopanib yields more QALYs than sunitinib was estimated to be 76%. For a threshold value of £30,000 per QALY gained, the probability that pazopanib is cost-effective versus sunitinib was estimated to be 95%. Pazopanib was dominant in most scenarios examined in deterministic sensitivity analyses. Conclusions Pazopanib is likely to be a cost-effective treatment option compared with sunitinib as first-line treatment of mRCC in the United Kingdom. PMID:28636648

Endothelial cell colony forming units derived from malignant breast diseases are resistant to tumor necrosis factor-α-induced apoptosis.

PubMed

Chou, Chen-Pin; Jiang, Shih Sheng; Pan, Huay-Ben; Yen, Yi-Chen; Tseng, Hui-Hwa; Hung, Yu-Ting; Wang, Ssu-Han; Chen, Yu-Lin; Chen, Ya-Wen

2016-11-24

Mobilisation of endothelial progenitor cells (EPCs) from the bone marrow is a crucial step in the formation of de novo blood vessels, and levels of peripheral blood EPCs have been shown to be elevated in certain malignant states. Using flow cytometry and a Hill-based colony forming unit (CFU) assay, the present study indicated that higher levels of CD34 and vascular endothelial growth factor receptor 2 (VEGFR2) double-positive EPCs, as well as increased formation of endothelial cell colony-forming units (EC-CFUs) are associated with benign and malignant breast diseases, providing possible indicators for breast disease detection. Gene expression profiles revealed a genetic difference between CD34 + VEGFR2 + EPCs and EC-CFUs. Decreased expression of tumour necrosis factor receptor 2 (TNFR2) signalling-related genes and inhibition of tumour necrosis factor (TNF)-induced signalling were demonstrated in EC-CFUs derived from patients with malignant breast disease in comparison with those from healthy controls. Interestingly, our data provided the first evidence that EC-CFUs derived from patients with malignant breast disease were resistant to TNF-α-induced apoptosis, indicating a plausible target for future therapeutic interventions.

Ternary gradient metal-organic frameworks.

PubMed

Liu, Chong; Rosi, Nathaniel L

2017-09-08

Gradient MOFs contain directional gradients of either structure or functionality. We have successfully prepared two ternary gradient MOFs based on bMOF-100 analogues, namely bMOF-100/102/106 and bMOF-110/100/102, via cascade ligand exchange reactions. The cubic unit cell parameter discrepancy within an individual ternary gradient MOF crystal is as large as ∼1 nm, demonstrating the impressive compatibility and flexibility of the component MOF materials. Because of the presence of a continuum of unit cells, the pore diameters within individual crystals also change in a gradient fashion from ∼2.5 nm to ∼3.0 nm for bMOF-100/102/106, and from ∼2.2 nm to ∼2.7 nm for bMOF-110/100/102, indicating significant porosity gradients. Like previously reported binary gradient MOFs, the composition of the ternary gradient MOFs can be easily controlled by adjusting the reaction conditions. Finally, X-ray diffraction and microspectrophotometry were used to analyse fractured gradient MOF crystals by comparing unit cell parameters and absorbance spectra at different locations, thus revealing the profile of heterogeneity (i.e. gradient distribution of properties) and further confirming the formation of ternary gradient MOFs.

Metasurface base on uneven layered fractal elements for ultra-wideband RCS reduction

NASA Astrophysics Data System (ADS)

Su, Jianxun; Cui, Yueyang; Li, Zengrui; Yang, Yaoqing Lamar; Che, Yongxing; Yin, Hongcheng

2018-03-01

A novel metasurface based on uneven layered fractal elements is designed and fabricated for ultra-wideband radar cross section (RCS) reduction in this paper. The proposed metasurface consists of two fractal subwavelength elements with different layer thickness. The reflection phase difference of 180° (±37°) between two unit cells covers an ultra-wide frequency range. Ultra-wideband RCS reduction results from the phase cancellation between two local waves produced by these two unit cells. The diffuse scattering of electromagnetic (EM) waves is caused by the randomized phase distribution, leading to a low monostatic and bistatic RCS simultaneously. This metasurface can achieve -10dB RCS reduction in an ultra-wide frequency range from 6.6 to 23.9 GHz with a ratio bandwidth (fH/fL) of 3.62:1 under normal incidences for both x- and y-polarized waves. Both the simulation and the measurement results are consistent to verify this excellent RCS reduction performance of the proposed metasurface.

Crosslinked wholly aromatic polyether membranes based on quinoline derivatives and their application in high temperature polymer electrolyte membrane fuel cells

NASA Astrophysics Data System (ADS)

Kallitsis, K. J.; Nannou, R.; Andreopoulou, A. K.; Daletou, M. K.; Papaioannou, D.; Neophytides, S. G.; Kallitsis, J. K.

2018-03-01

An AB type difunctional quinoline based monomer bearing a pentafluorophenyl unit combined with a phenol functionality is being synthesized and homopolymerized to create linear aromatic polyethers as polymer electrolytes for HT-PEM FCs applications. Several conditions are tested for the optimized synthesis of the monomer and homopolymer. Additionally, covalent crosslinking through aromatic polyether bond formation enables the creation of wholly aromatic crosslinked polymeric electrolyte membranes. More specifically, the perfluorophenyl units are crosslinked with other hydroxyl end functionalized moieties, providing membranes with enhanced chemical and mechanical properties that are moreover easily doped with phosphoric acid even at ambient temperatures. All membranes are evaluated for their structural and thermal characteristics and their doping ability with phosphoric acid. Selected crosslinked membranes are further tested in terms of their single cell performance at the temperature range 160 °C-200 °C showing promising performance and high conductivity values even up to 0.2 S cm-1 in some cases.

MSuPDA: A Memory Efficient Algorithm for Sequence Alignment.

PubMed

Khan, Mohammad Ibrahim; Kamal, Md Sarwar; Chowdhury, Linkon

2016-03-01

Space complexity is a million dollar question in DNA sequence alignments. In this regard, memory saving under pushdown automata can help to reduce the occupied spaces in computer memory. Our proposed process is that anchor seed (AS) will be selected from given data set of nucleotide base pairs for local sequence alignment. Quick splitting techniques will separate the AS from all the DNA genome segments. Selected AS will be placed to pushdown automata's (PDA) input unit. Whole DNA genome segments will be placed into PDA's stack. AS from input unit will be matched with the DNA genome segments from stack of PDA. Match, mismatch and indel of nucleotides will be popped from the stack under the control unit of pushdown automata. During the POP operation on stack, it will free the memory cell occupied by the nucleotide base pair.

Molecular design and theoretical characterization of benzodithiophene based organic photovoltaic materials

NASA Astrophysics Data System (ADS)

Bhattacharya, Labanya; Sahu, Sridhar

2018-05-01

Two different oligomers, containing methyl substituted Benzodithiophene (BDT) as donor unit, fluorinated thiophene as the π-bridge unit and two different kinds of acceptors based on fluorinated benzothiadiazole, fluorinated benzoselenadiazole units are designed for bulk heterojunction (BHJ) organic solar cell (OSC). The ground and excited state properties of those donor-π-acceptor-π-donor (D-π-A-π-D) oligomeric configurations are characterized via density functional (DFT) and time dependent density functional theory (TD-DFT). The parameters such as dipole moment (ρ), chemical potential (µ), electronegativity (χ), frontier molecular orbital (FMO) analysis, HOMO-LUMO gap, open circuit voltage (Voc) and driving force (ΔE) are calculated to analyze geometrical, electronic structural, quantum chemical and photovoltaic properties of the compounds. In addition, optical absorption spectra are also presented for the optical characterization of the compounds.

40 CFR Appendix A to Part 76 - Phase I Affected Coal-Fired Utility Units With Group 1 or Cell Burner Boilers

Code of Federal Regulations, 2011 CFR

2011-07-01

... Units With Group 1 or Cell Burner Boilers A Appendix A to Part 76 Protection of Environment... 1 or Cell Burner Boilers Table 1—Phase I Tangentially Fired Units State Plant Unit Operator ALABAMA... TOWER 9 CEN ILLINOIS PUB SER. INDIANA CULLEY 2 STHERN IND GAS & EL. INDIANA CULLEY 3 STHERN IND GAS & EL...

Analysis of Fc(epsilon)RI-mediated mast cell stimulation by surface-carried antigens.

PubMed Central

Schweitzer-Stenner, R; Tamir, I; Pecht, I

1997-01-01

Clustering of the type I receptor for IgE (Fc[epsilon]RI) on mast cells initiates a cascade of biochemical processes that result in secretion of inflammatory mediators. To determine the Fc(epsilon)RI proximity, cluster size, and mobility requirements for initiating the Fc(epsilon)RI cascade, a novel experimental protocol has been developed in which mast cells are reacted with glass surfaces carrying different densities of both antigen and bound IgE, and the cell's secretory response to these stimuli is measured. The results have been analyzed in terms of a model based on the following assumptions: 1) the glass surface antigen distribution and consequently that of the bound IgE are random; 2) Fc(epsilon)RI binding to these surface-bound IgEs immobilizes the former and saturates the latter; 3) the cell surface is formally divided into small elements, which function as a secretory stimulus unit when occupied by two or more immobilized IgE-Fc(epsilon)RI complexes; 4) alternatively, similar stimulatory units can be formed by binding of surface-carried IgE dimers to two Fc(epsilon)RI. This model yielded a satisfactory and self-consistent fitting of all of the different experimental data sets. Hence the present results establish the essential role of Fc(epsilon)RI immobilization for initiating its signaling cascade. Moreover, it provides independent support for the notion that as few as two Fc(epsilon)RIs immobilized at van der Waals contact constitute an "elementary stimulatory unit" leading to mast cell (RBL-2H3 line) secretory response. PMID:9168023

A smart polymeric platform for multistage nucleus-targeted anticancer drug delivery.

PubMed

Zhong, Jiaju; Li, Lian; Zhu, Xi; Guan, Shan; Yang, Qingqing; Zhou, Zhou; Zhang, Zhirong; Huang, Yuan

2015-10-01

Tumor cell nucleus-targeted delivery of antitumor agents is of great interest in cancer therapy, since the nucleus is one of the most frequent targets of drug action. Here we report a smart polymeric conjugate platform, which utilizes stimulus-responsive strategies to achieve multistage nuclear drug delivery upon systemic administration. The conjugates composed of a backbone based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer and detachable nucleus transport sub-units that sensitive to lysosomal enzyme. The sub-units possess a biforked structure with one end conjugated with the model drug, H1 peptide, and the other end conjugated with a novel pH-responsive targeting peptide (R8NLS) that combining the strength of cell penetrating peptide and nuclear localization sequence. The conjugates exhibited prolonged circulation time and excellent tumor homing ability. And the activation of R8NLS in acidic tumor microenvironment facilitated tissue penetration and cellular internalization. Once internalized into the cell, the sub-units were unleashed for nuclear transport through nuclear pore complex. The unique features resulted in 50-fold increase of nuclear drug accumulation relative to the original polymer-drug conjugates in vitro, and excellent in vivo nuclear drug delivery efficiency. Our report provides a strategy in systemic nuclear drug delivery by combining the microenvironment-responsive structure and detachable sub-units. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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.

Microfluidic-based mini-metagenomics enables discovery of novel microbial lineages from complex environmental samples.

PubMed

Yu, Feiqiao Brian; Blainey, Paul C; Schulz, Frederik; Woyke, Tanja; Horowitz, Mark A; Quake, Stephen R

2017-07-05

Metagenomics and single-cell genomics have enabled genome discovery from unknown branches of life. However, extracting novel genomes from complex mixtures of metagenomic data can still be challenging and represents an ill-posed problem which is generally approached with ad hoc methods. Here we present a microfluidic-based mini-metagenomic method which offers a statistically rigorous approach to extract novel microbial genomes while preserving single-cell resolution. We used this approach to analyze two hot spring samples from Yellowstone National Park and extracted 29 new genomes, including three deeply branching lineages. The single-cell resolution enabled accurate quantification of genome function and abundance, down to 1% in relative abundance. Our analyses of genome level SNP distributions also revealed low to moderate environmental selection. The scale, resolution, and statistical power of microfluidic-based mini-metagenomics make it a powerful tool to dissect the genomic structure of microbial communities while effectively preserving the fundamental unit of biology, the single cell.

Tilted cellulose arrangement as a novel mechanism for hygroscopic coiling in the stork's bill awn.

PubMed

Abraham, Yael; Tamburu, Carmen; Klein, Eugenia; Dunlop, John W C; Fratzl, Peter; Raviv, Uri; Elbaum, Rivka

2012-04-07

The sessile nature of plants demands the development of seed-dispersal mechanisms to establish new growing loci. Dispersal strategies of many species involve drying of the dispersal unit, which induces directed contraction and movement based on changing environmental humidity. The majority of researched hygroscopic dispersal mechanisms are based on a bilayered structure. Here, we investigate the motility of the stork's bill (Erodium) seeds that relies on the tightening and loosening of a helical awn to propel itself across the surface into a safe germination place. We show that this movement is based on a specialized single layer consisting of a mechanically uniform tissue. A cell wall structure with cellulose microfibrils arranged in an unusually tilted helix causes each cell to spiral. These cells generate a macroscopic coil by spiralling collectively. A simple model made from a thread embedded in an isotropic foam matrix shows that this cellulose arrangement is indeed sufficient to induce the spiralling of the cells.

Deciphering the Role of Sulfonated Unit in Heparin-Mimicking Polymer to Promote Neural Differentiation of Embryonic Stem Cells.

PubMed

Lei, Jiehua; Yuan, Yuqi; Lyu, Zhonglin; Wang, Mengmeng; Liu, Qi; Wang, Hongwei; Yuan, Lin; Chen, Hong

2017-08-30

Glycosaminoglycans (GAGs), especially heparin and heparan sulfate (HS), hold great potential for inducing the neural differentiation of embryonic stem cells (ESCs) and have brought new hope for the treatment of neurological diseases. However, the disadvantages of natural heparin/HS, such as difficulty in isolating them with a sufficient amount, highly heterogeneous structure, and the risk of immune responses, have limited their further therapeutic applications. Thus, there is a great demand for stable, controllable, and well-defined synthetic alternatives of heparin/HS with more effective biological functions. In this study, based upon a previously proposed unit-recombination strategy, several heparin-mimicking polymers were synthesized by integrating glucosamine-like 2-methacrylamido glucopyranose monomers (MAG) with three sulfonated units in different structural forms, and their effects on cell proliferation, the pluripotency, and the differentiation of ESCs were carefully studied. The results showed that all the copolymers had good cytocompatibility and displayed much better bioactivity in promoting the neural differentiation of ESCs as compared to natural heparin; copolymers with different sulfonated units exhibited different levels of promoting ability; among them, copolymer with 3-sulfopropyl acrylate (SPA) as a sulfonated unit was the most potent in promoting the neural differentiation of ESCs; the promoting effect is dependent on the molecular weight and concentration of P(MAG-co-SPA), with the highest levels occurring at the intermediate molecular weight and concentration. These results clearly demonstrated that the sulfonated unit in the copolymers played an important role in determining the promoting effect on ESCs' neural differentiation; SPA was identified as the most potent sulfonated unit for copolymer with the strongest promoting ability. The possible reason for sulfonated unit structure as a vital factor influencing the ability of the copolymers may be attributed to the difference in electrostatic and steric hindrance effect. The synthetic heparin-mimicking polymers obtained here can offer an effective alternative to heparin/HS and have great therapeutic potential for nervous system diseases.

The Vertebrate Brain, Evidence of Its Modular Organization and Operating System: Insights into the Brain's Basic Units of Structure, Function, and Operation and How They Influence Neuronal Signaling and Behavior

PubMed Central

Baslow, Morris H.

2011-01-01

The human brain is a complex organ made up of neurons and several other cell types, and whose role is processing information for use in eliciting behaviors. However, the composition of its repeating cellular units for both structure and function are unresolved. Based on recent descriptions of the brain's physiological “operating system”, a function of the tri-cellular metabolism of N-acetylaspartate (NAA) and N-acetylaspartylglutamate (NAAG) for supply of energy, and on the nature of “neuronal words and languages” for intercellular communication, insights into the brain's modular structural and functional units have been gained. In this article, it is proposed that the basic structural unit in brain is defined by its physiological operating system, and that it consists of a single neuron, and one or more astrocytes, oligodendrocytes, and vascular system endothelial cells. It is also proposed that the basic functional unit in the brain is defined by how neurons communicate, and consists of two neurons and their interconnecting dendritic–synaptic–dendritic field. Since a functional unit is composed of two neurons, it requires two structural units to form a functional unit. Thus, the brain can be envisioned as being made up of the three-dimensional stacking and intertwining of myriad structural units which results not only in its gross structure, but also in producing a uniform distribution of binary functional units. Since the physiological NAA–NAAG operating system for supply of energy is repeated in every structural unit, it is positioned to control global brain function. PMID:21720525

Modification of D-A-π-A configuration toward a high-performance triphenylamine-based sensitizer for dye-sensitized solar cells: a theoretical investigation.

PubMed

Tarsang, Ruangchai; Promarak, Vinich; Sudyoadsuk, Taweesak; Namuangruk, Supawadee; Kungwan, Nawee; Jungsuttiwong, Siriporn

2014-12-01

In an attempt to shed light on how the addition of a benzothiadiazole (BTD) moiety influences the properties of dyes, a series of newly designed triphenylamine-based sensitizers incorporating a BTD unit as an additional electron-withdrawing group in a specific donor-acceptor-π-acceptor architecture has been investigated. We found that different positions of the BTD unit provided significantly different responses for light absorption. Among these, it was established that the further the BTD unit is away from the donor part, the broader the absorption spectra, which is an observation that can be applied to improve light-harvesting ability. However, when the BTD unit is connected to the anchoring group a faster, unfavorable charge recombination takes place; therefore, a thiophene unit was inserted between these two acceptors, providing redshifted absorption spectra as well as blocking unfavorable charge recombination. The results of our calculations provide valuable information and illustrate the potential benefits of using computation-aided sensitizer design prior to further experimental synthesis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microchannel Distillation of JP-8 Jet Fuel for Sulfur Content Reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Feng; Stenkamp, Victoria S.; TeGrotenhuis, Ward E.

2006-09-16

In microchannel based distillation processes, thin vapor and liquid films are contacted in small channels where mass transfer is diffusion-limited. The microchannel architecture enables improvements in distillation processes. A shorter height equivalent of a theoretical plate (HETP) and therefore a more compact distillation unit can be achieved. A microchannel distillation unit was used to produce a light fraction of JP-8 fuel with reduced sulfur content for use as feed to produce fuel-cell grade hydrogen. The HETP of the microchannel unit is discussed, as well as the effects of process conditions such as feed temperature, flow rate, and reflux ratio.

In vitro fertilization and stem cell harvesting from human embryos: the law and practice in the United States.

PubMed

Hook, C Christopher

2010-07-01

The challenges before science and medicine are these: science must explore the natural world as thoroughly as possible, while still honoring, protecting, serving and preserving the subject of its investigations, and the human beings for whom it is a tool; medicine must confront disease and disability as effectively as possible, while also honoring, protecting, and preserving those beings for whom it serves - all of those beings, not just some, or even most, at the potential expense of others. These goals are challenged by embryo-destructive human embryonic stem cell research. The human embryo is a human being as clearly defined by embryology, and as such should be protected by the codes governing human subject research. However, because of the "potential" benefits offered by pluripotent stem cells, coupled with abortion politics and a very poorly regulated infertility industry, United States governmental advisory commissions and the scientific, medical, and political communities have attempted to define away the humanity of the human embryo, with a few notable exceptions. Because infertility treatments in the United States are poorly regulated, there are large numbers of supernumerary embryos in cryopreservation. However, only a tiny portion of these will ever be potentially available for research, and thus are not a realistic source of the cells necessary to provide treatments to the millions who might benefit from proposed stem cell based therapies. Cloning will not be the answer either, given the millions of women who must be exploited to provide sufficient numbers of eggs to generate the cloned cell lines. Moreover, the disposition decisions parents must make for their extra embryos are often agonizing, and not uncommonly change. The use of supernumerary embryos as a source for human embryonic stem cells is unethical, will never be a sufficient source for the medical treatments expected from stem cell research, and is often a source of great distress for the conceiving parents. The United States experience is not a positive model for other countries to emulate.

Quantum dot nanoprobe-based quantitative analysis for prostate cancer (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kang, Benedict J.; Jang, Gun Hyuk; Park, Sungwook; Lee, Kwan Hyi

2016-09-01

Prostate cancer causes one of the leading cancer-related deaths among the Caucasian adult males in Europe and the United State of America. However, it has a high recovery rate indicating when a proper treatment is delivered to a patient. There are cases of over- or under-treatments which exacerbate the disease states indicating the importance of proper therapeutic approach depending on stage of the disease. Recognition of the unmet needs has raised a need for stratification of the disease. There have been attempts to stratify based on biomarker expression patterns in the course of disease progression. To closely observe the biomarker expression patterns, we propose the use of quantitative imaging method by using fabricated quantum dot-based nanoprobe to quantify biomarker expression on the surface of prostate cancer cells. To characterize the cell line and analyze the biomarker levels, cluster of differentiation 44 (CD 44), prostate specific membrane antigen (PSMA), and epithelial cell adhesion molecule (EpCAM) are used. Each selected biomarker per cell line has been quantified from which we established a signature of biomarkers of a prostate cancer cell line.

Preparation of red blood cell concentrates and plasma units from whole blood held overnight using a hollow-fibre separation system.

PubMed

Johnson, L; Kwok, M; Marks, D C

2015-02-01

The ErySep system represents an alternative to centrifuge-based whole blood (WB) separation, using gravity and filtration through hollow-fibres (0·2 µm pore size) to produce red blood cell (RBC) and plasma components. The aim of this study was to characterise the quality of ErySep RBC and plasma units compared with standard products from WB held overnight. Two ABO-compatible WB units (n = 24) were pooled and split to produce matched products. One of the WB units was separated into components using the ErySep system (ErySep; n = 12), whereas the other units were separated by centrifugation (control; n = 12). RBC units were stored at 2-6 °C and assessed for in vitro quality over 42 days of storage. Plasma was frozen at -30 °C and tested upon thawing. Processing WB with the ErySep system took longer than controls. The ErySep RBC units were of an appropriate volume (307 ± 17 mL) and contained sufficient Hb (50 ± 2 g unit(-1) ). ErySep RBC components contained more microparticles relative to controls at expiry. The plasma volume, total protein, coagulation factor activity (fibrinogen, FV, FVIII) and number of microparticles was lower in the ErySep units compared with controls. Following overnight hold of WB, the ErySep system was capable of producing RBC components that met specifications. However, the ErySep plasma components did not meet quality specifications. © 2015 British Blood Transfusion Society.

Dental unit waterlines disinfection using hypochlorous acid-based disinfectant

PubMed Central

Shajahan, Irfana Fathima; Kandaswamy, D; Srikanth, Padma; Narayana, L Lakshmi; Selvarajan, R

2016-01-01

Objective: The purpose of the study was to investigate the efficacy of a new disinfectant to disinfect the dental unit waterlines. Materials and Methods: New dental unit waterlines were installed in 13 dental chairs, and biofilm was allowed to grow for 10 days. Disinfection treatment procedure was carried out in the 12 units, and one unit was left untreated. The dental unit waterlines were removed and analyzed using the scanning electron microscope (SEM) (TESCAN VEGA3 SBU). Result: On examination, SEM images showed that there was no slime layer or bacterial cells seen in any of the 12 cut sections obtained from the treated dental waterlines which mean that there was no evident of biofilm formation. Untreated dental unit waterlines showed a microbial colonization with continuous filamentous organic matrix. There was significant biofilm formation in the control tube relative to the samples. Conclusion: The tested disinfectant was found to be effective in the removal of biofilm from the dental unit waterlines. PMID:27563184

Zn- and Co-based layered double hydroxides: prediction of the a parameter from the fraction of trivalent cations and vice versa

PubMed Central

Richardson, Ian G.

2013-01-01

A recently proposed method to calculate the a parameter of the unit cell of layered double hydroxides from the fraction of trivalent cations is extended to Zn- and Co-based phases. It is shown to be useful as a sanity test for extant and future structure determinations and computer-simulation studies. PMID:23873067

Combinatorial compatibility as habit-controlling factor in lysozyme crystallization I. Monomeric and tetrameric F faces derived graph-theoretically

NASA Astrophysics Data System (ADS)

Strom, C. S.; Bennema, P.

1997-03-01

A series of two articles discusses possible morphological evidence for oligomerization of growth units in the crystallization of tetragonal lysozyme, based on a rigorous graph-theoretic derivation of the F faces. In the first study (Part I), the growth layers are derived as valid networks satisfying the conditions of F slices in the context of the PBC theory using the graph-theoretic method implemented in program FFACE [C.S. Strom, Z. Krist. 172 (1985) 11]. The analysis is performed in monomeric and alternative tetrameric and octameric formulations of the unit cell, assuming tetramer formation according to the strongest bonds. F (flat) slices with thickness Rdhkl ( {1}/{2} < R ≤ 1 ) are predicted theoretically in the forms 1 1 0, 0 1 1, 1 1 1. The relevant energies are established in the broken bond model. The relation between possible oligomeric specifications of the unit cell and combinatorially feasible F slice compositions in these orientations is explored.

The relationships between deformation mechanisms and mechanical properties of additively manufactured porous biomaterials.

PubMed

Kadkhodapour, J; Montazerian, H; Darabi, A Ch; Zargarian, A; Schmauder, S

2017-06-01

Modulating deformation mechanism through manipulating morphological parameters of scaffold internal pore architecture provides potential to tailor the overall mechanical properties under physiological loadings. Whereas cells sense local strains, cell differentiation is also impressed by the elastic deformations. In this paper, structure-property relations were developed for Ti6-Al-4V scaffolds designed based on triply periodic minimal surfaces. 10mm cubic scaffolds composed of 5×5×5 unit cells formed of F-RD (bending dominated) and I-WP (stretching dominated) architectures were additively manufactured at different volume fractions and subjected to compressive tests. The first stages of deformation for stretching dominated structure, was accompanied by bilateral layer-by-layer failure of unit cells owing to the buckling of micro-struts, while for bending dominated structure, namely F-RD, global shearing bands appeared since the shearing failure of struts in the internal architecture. Promoted mechanical properties were found for stretching dominated structure since the global orientation of struts were parallel to loading direction while inclination of struts diminished specific properties for bending dominated structure. Moreover, elastic-plastic deformation was computationally studied by applying Johnson-Cook damage model to the voxel-based models in FE analysis. Scaling analysis was performed for mechanical properties with respect to the relative density thereby failure mechanism was correlated to the constants of power law describing mechanical properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Utilizing Benzotriazole and Indacenodithiophene Units to Construct both Polymeric Donor and Small Molecular Acceptors to Realize Organic Solar Cells with High Open-Circuit Voltages beyond 1.2 V

NASA Astrophysics Data System (ADS)

Tang, Ailing; Chen, Fan; Xiao, Bo; Yang, Jing; Li, Jianfeng; Wang, Xiaochen; Zhou, Erjun

2018-05-01

Devolopment of organic solar cells with high open-circuit voltage (VOC) and power conversion efficiency (PCE) simutaniously plays a significant role, but there is no guideline how to choose the suitable photovoltaic material combinations. In this study, we adopted a simple and feasible strategy by utilizing the same electron-donating unit and electron-accepting segment to construct both polymeric donor and small molecular acceptors. The p-type polymer of PIDT-DTffBTA is designed by inserting conjugated bridge between indacenodithiophene (IDT) and fluorinated benzotriazole (BTA), while the n-type small molecules of BTAx (x = 1, 2, 3) are obtained by introducing different end-capped groups to BTA-IDT-BTA backbone. PIDT-DTffBTA: BTAx (x = 1-3) based photovolatic devices can realize high VOC of 1.21-1.37 V with the very small voltage loss (0.55-0.60 V), while only the PIDT-DTffBTA: BTA3 based device possesses the enough driving force for efficient hole and electron transfer and yields the optimal PCE of 5.67%, which is among the highest value for organic solar cells with a VOC beyond 1.20 V reported so far. Our results provide a simple and effective method to obtain fullerene-free organic solar cells with a high VOC and PCE.

Field experiment of 800× off-axis XR-Köhler concentrator module on a carousel tracker

NASA Astrophysics Data System (ADS)

Yamada, Noboru; Okamoto, Kazuya; Ijiro, Toshikazu; Suzuki, Takao; Maemura, Toshihiko; Kawaguchi, Takashi; Takahashi, Hiroshi; Sato, Takashi; Hernandez, Maikel; Benitez, Pablo; Chaves, Julio; Cvetkovic, Aleksandra; Vilaplana, Juan; Mohedano, Ruben; Mendes-Lopes, Joao; Miñano, Juan Carlos

2013-09-01

This paper presents the design and preliminary experimental results of a concentrator-type photovoltaic module based on a free-form off-axis 800×XR-Köhler concentrator. The off-axis XR-Köhler concentrator is one of the advanced concentrators that perform high concentration with a large acceptance angle and excellent irradiance uniformity on a solar cell. As a result of on-sun characterization of the unglazed single-cell unit test rig, the temperature-corrected DC module efficiency was 32.2% at 25 °C without an anti-reflective (AR) coating on the secondary optics, and the acceptance angle was more than ±1.0°. In addition, the non-corrected DC efficiency of an individual cell in a glazed 8-cell unit module mounted on a carousel tracking system was measured. The individual efficiency deviated in the range of 24.3-27.4%, owing to the mirror shape and alignment errors. The resultant series-connected efficiency was approximately 25% at direct normal irradiation (DNI) of 770 W/m2.

A hanging drop culture method to study terminal erythroid differentiation.

PubMed

Gutiérrez, Laura; Lindeboom, Fokke; Ferreira, Rita; Drissen, Roy; Grosveld, Frank; Whyatt, David; Philipsen, Sjaak

2005-10-01

To design a culture method allowing the quantitative and qualitative analysis of terminal erythroid differentiation. Primary erythroid progenitors derived either from mouse tissues or from human umbilical cord blood were differentiated using hanging drop cultures and compared to methylcellulose cultures. Cultured cells were analyzed by FACS to assess differentiation. We describe a practical culture method by adapting the previously described hanging drop culture system to conditions allowing terminal differentiation of primary erythroid progenitors. Using minimal volumes of media and small numbers of cells, we obtained quantitative terminal erythroid differentiation within two days of culture in the case of murine cells and 4 days in the case of human cells. The established methods for ex vivo culture of primary erythroid progenitors, such as methylcellulose-based burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) assays, allow the detection of committed erythroid progenitors but are of limited value to study terminal erythroid differentiation. We show that the application of hanging drop cultures is a practical alternative that, in combination with clonogenic assays, enables a comprehensive assessment of the behavior of primary erythroid cells ex vivo in the context of genetic and drug-induced perturbations.

Voc Degradation in TF-VLS Grown InP Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yubo; Sun, Xingshu; Johnston, Steve

2016-11-21

Here we consider two hypotheses to explain the open-circuit voltage (VOC) degradation observed in thin-film vapor-liquid-solid (TF-VLS) grown p-type InP photovoltaic cells: bandgap narrowing and local shunting. First, a bandgap (Eg) narrowing effect is hypothesized, based on the surface inhomogeneity of VLS InP captured by the photoluminescence (PL) image. The PL data was used to estimate a spatially-resolved active VOC across surface of the InP sample. Combining this data with the effective Jsc allowed an assessment of the I-V characteristics of individual unit cells. Next, an H-SPICE diode compact model was utilized to reproduce the I-V characteristics of the wholemore » sample. We find a good fit to the I-V performance of TF-VLS grown InP solar cell. Second, a local shunting effect was also considered as an alternative explanation of the VOC degradation effect. Again, PL image data was used, and small local shunt resistance was added in arbitrary elementary unit cells to represent certain dark spots seen in the PL image and dictate the VOC degradation occurred in the sample.« less

Compact localized states and flat-band generators in one dimension

NASA Astrophysics Data System (ADS)

Maimaiti, Wulayimu; Andreanov, Alexei; Park, Hee Chul; Gendelman, Oleg; Flach, Sergej

2017-03-01

Flat bands (FB) are strictly dispersionless bands in the Bloch spectrum of a periodic lattice Hamiltonian, recently observed in a variety of photonic and dissipative condensate networks. FB Hamiltonians are fine-tuned networks, still lacking a comprehensive generating principle. We introduce a FB generator based on local network properties. We classify FB networks through the properties of compact localized states (CLS) which are exact FB eigenstates and occupy U unit cells. We obtain the complete two-parameter FB family of two-band d =1 networks with nearest unit cell interaction and U =2 . We discover a novel high symmetry sawtooth chain with identical hoppings in a transverse dc field, easily accessible in experiments. Our results pave the way towards a complete description of FBs in networks with more bands and in higher dimensions.

Implementation of Fiber Substructuring Into Strain Rate Dependent Micromechanics Analysis of Polymer Matrix Composites

NASA Technical Reports Server (NTRS)

Goldberg, Robert K.

2001-01-01

A research program is in progress to develop strain rate dependent deformation and failure models for the analysis of polymer matrix composites subject to impact loads. Previously, strain rate dependent inelastic constitutive equations developed to model the polymer matrix were incorporated into a mechanics of materials based micromechanics method. In the current work, the micromechanics method is revised such that the composite unit cell is divided into a number of slices. Micromechanics equations are then developed for each slice, with laminate theory applied to determine the elastic properties, effective stresses and effective inelastic strains for the unit cell. Verification studies are conducted using two representative polymer matrix composites with a nonlinear, strain rate dependent deformation response. The computed results compare well to experimentally obtained values.

The baffling human body and the boundless nanomaterial boon-a trap for cancer crab.

PubMed

Jeelani, S; Asokan, G S; Anuradha, G; Parthiban, J; Sivasankari, T

2014-07-01

Life is a balance of infinite physiochemical balanced harmonies and the basic unit cell is responsible in maintaining it. Cardiovascular diseases and Cancer are the prime causes of death worldwide. Cancerous cells break the harmonious balance and result in uncontrolled growth and spread. Emerging among the existing modalities for management of cancer, as a ray of hope is Nanotechnology based treatment. Dendrimers, Quantum dots and nanobubbles contribute significantly as part of nano based diagnosis and treatment in the management of cancer. Dendrimers are nanoparticles which employ the principle of Trojan horse strategy in that encapsulation and conjugation of anti cancer agents helps in targeting the cancerous cells specifically without affecting the adjacent healthy cells. Quantum dots are cadmium based nanoparticles which when exposed to UV light glow and help in destroying the cancerous cells in the incipient stage. Nanobubbles are generated with short pulses of laser, which helps in identifying the individual cancerous cells and explodes them. Apart from them other technologies such as liposomes, fullerenes, carbon nanotubes, nanoshells, paramagnetic nanoparticles, nanoburrs, respirocytes, microbiovores, nanopores, smart coating and nano bandaid contribute a great lot as boundless nanomaterial boon for the management of cancer, cardiovascular problems and overall systemic health.

Drug Self-Delivery Systems Based on Hyperbranched Polyprodrugs towards Tumor Therapy.

PubMed

Duan, Xiao; Chen, Jianxin; Wu, Yalan; Wu, Si; Shao, Dongyan; Kong, Jie

2018-04-16

Amphiphilic hyperbranched polyprodrugs (DOX-S-S-PEG) with drug repeat units in hydrophobic core linked by disulfide bonds were developed as drug self-delivery systems for cancer therapy. The hydroxyl groups and the amine group in doxorubicin (DOX) were linked by 3,3'-dithiodipropanoic acid as hydrophobic hyperbranched cores, then amino-terminated polyethylene glycol monomethyl ether (mPEG-NH 2 ) as hydrophilic shell was linked to hydrophobic cores to form amphiphilic and glutathione (GSH)-responsive micelle of hyperbranched polyprodrugs. The amphiphilic micelles can be disrupted under GSH (1 mg mL -1 ) circumstance. Cell viability of A549 cells and 293T cells was evaluated by CCK-8 and Muse Annexin V & Dead Cell Kit. The disrupted polyprodrugs maintained drug activity for killing tumor cells. Meanwhile, the undisrupted polyprodrugs possessed low cytotoxicity to normal cells. The cell uptake experiments showed that the micelles of DOX-S-S-PEG were taken up by A549 cells and distributed to cell nuclei. Thus, the drug self-delivery systems with drug repeat units in hydrophobic cores linked by disulfide bonds showed significant special advantages: 1) facile one-pot synthesis; 2) completely without toxic or non-degradable polymers; 3) DOX itself functions as fluorescent labeled molecule and self-delivery carrier; 4) drug with inactive form in hyperbranched cores and low cytotoxicity to normal cells. These advantages make them excellent drug self-delivery systems for potential high efficient cancer therapy. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Promoting effects of serotonin on hematopoiesis: ex vivo expansion of cord blood CD34+ stem/progenitor cells, proliferation of bone marrow stromal cells, and antiapoptosis.

PubMed

Yang, Mo; Li, Karen; Ng, Pak Cheung; Chuen, Carmen Ka Yee; Lau, Tze Kin; Cheng, Yuan Shan; Liu, Yuan Sheng; Li, Chi Kong; Yuen, Patrick Man Pan; James, Anthony Edward; Lee, Shuk Man; Fok, Tai Fai

2007-07-01

Serotonin is a monoamine neurotransmitter that has multiple extraneuronal functions. We previously reported that serotonin exerted mitogenic stimulation on megakaryocytopoiesis mediated by 5-hydroxytryptamine (5-HT)2 receptors. In this study, we investigated effects of serotonin on ex vivo expansion of human cord blood CD34+ cells, bone marrow (BM) stromal cell colony-forming unit-fibroblast (CFU-F) formation, and antiapoptosis of megakaryoblastic M-07e cells. Our results showed that serotonin at 200 nM significantly enhanced the expansion of CD34+ cells to early stem/progenitors (CD34+ cells, colony-forming unit-mixed [CFU-GEMM]) and multilineage committed progenitors (burst-forming unit/colony-forming unit-erythroid [BFU/CFU-E], colony-forming unit-granulocyte macrophage, colony-forming unit-megakaryocyte, CD61+ CD41+ cells). Serotonin also increased nonobese diabetic/severe combined immunodeficient repopulating cells in the expansion culture in terms of human CD45+, CD33+, CD14+ cells, BFU/CFU-E, and CFU-GEMM engraftment in BM of animals 6 weeks post-transplantation. Serotonin alone or in addition to fibroblast growth factor, platelet-derived growth factor, or vascular endothelial growth factor stimulated BM CFU-F formation. In M-07e cells, serotonin exerted antiapoptotic effects (annexin V, caspase-3, and propidium iodide staining) and reduced mitochondria membrane potential damage. The addition of ketanserin, a competitive antagonist of 5-HT2 receptor, nullified the antiapoptotic effects of serotonin. Our data suggest the involvement of serotonin in promoting hematopoietic stem cells and the BM microenvironment. Serotonin could be developed for clinical ex vivo expansion of hematopoietic stem cells for transplantation. Disclosure of potential conflicts of interest is found at the end of this article.

Electrochemically-driven large amplitude pH cycling for acid-base driven DNA denaturation and renaturation.

PubMed

Wang, Yong-Chun; Lin, Cong-Bin; Su, Jian-Jia; Ru, Ying-Ming; Wu, Qiao; Chen, Zhao-Bin; Mao, Bing-Wei; Tian, Zhao-Wu

2011-06-15

In this paper, we present an electrochemically driven large amplitude pH alteration method based on a serial electrolytic cell involving a hydrogen permeable bifacial working electrode such as Pd thin foil. The method allows solution pH to be changed periodically up to ±4~5 units without additional alteration of concentration and/or composition of the system. Application to the acid-base driven cyclic denaturation and renaturation of 290 bp DNA fragments is successfully demonstrated with in situ real-time UV spectroscopic characterization. Electrophoretic analysis confirms that the denaturation and renaturation processes are reversible without degradation of the DNA. The serial electrolytic cell based electrochemical pH alteration method presented in this work would promote investigations of a wide variety of potential-dependent processes and techniques.

Significant reduction in red blood cell transfusions in a general hospital after successful implementation of a restrictive transfusion policy supported by prospective computerized order auditing.

PubMed

Yerrabothala, Swaroopa; Desrosiers, Kevin P; Szczepiorkowski, Zbigniew M; Dunbar, Nancy M

2014-10-01

Our hospital transfusion policy was recently revised to recommend single-unit red blood cell transfusion (RBC TXN) for nonbleeding inpatients when the hemoglobin (Hb) level is not more than 7 g/dL. Our computerized provider order entry system was reconfigured to provide real-time decision support using prospective computerized order auditing based on the most recent Hb level and to remove the single-click ordering option for 2-unit RBC TXNs to enhance compliance. This study was undertaken to assess the impact of these changes on hospital transfusion practice. This study analyzed the total number of transfusion events, proportion of single and 2-unit transfusions and the Hb transfusion trigger in the preimplementation period (October 2011-March 2012) compared to the postimplementation period (October 2012-March 2013). In the postimplementation period the total number of RBC units transfused/1000 patient-days decreased from 60.8 to 44.2 (p < 0.0001). The proportion of 2-unit TXNs decreased from 47% to 15% (p < 0.0001). We also observed significant decreases in pretransfusion Hb triggers. Implementation of restrictive transfusion policy supported by prospective computerized order auditing has resulted in significantly decreased RBC utilization at our institution. © 2014 AABB.

Impact of cell size on inventory and mapping errors in a cellular geographic information system

NASA Technical Reports Server (NTRS)

Wehde, M. E. (Principal Investigator)

1979-01-01

The author has identified the following significant results. The effect of grid position was found insignificant for maps but highly significant for isolated mapping units. A modelable relationship between mapping error and cell size was observed for the map segment analyzed. Map data structure was also analyzed with an interboundary distance distribution approach. Map data structure and the impact of cell size on that structure were observed. The existence of a model allowing prediction of mapping error based on map structure was hypothesized and two generations of models were tested under simplifying assumptions.

Implementation of stimulated Raman scattering microscopy for single cell analysis

NASA Astrophysics Data System (ADS)

D'Arco, Annalisa; Ferrara, Maria Antonietta; Indolfi, Maurizio; Tufano, Vitaliano; Sirleto, Luigi

2017-05-01

In this work, we present successfully realization of a nonlinear microscope, not purchasable in commerce, based on stimulated Raman scattering. It is obtained by the integration of a femtosecond SRS spectroscopic setup with an inverted research microscope equipped with a scanning unit. Taking account of strength of vibrational contrast of SRS, it provides label-free imaging of single cell analysis. Validation tests on images of polystyrene beads are reported to demonstrate the feasibility of the approach. In order to test the microscope on biological structures, we report and discuss the label-free images of lipid droplets inside fixed adipocyte cells.

Polymersomes containing iron sulfide (FeS) as primordial cell model : for the investigation of energy providing redox reactions.

PubMed

Alpermann, Theodor; Rüdel, Kristin; Rüger, Ronny; Steiniger, Frank; Nietzsche, Sandor; Filiz, Volkan; Förster, Stephan; Fahr, Alfred; Weigand, Wolfgang

2011-04-01

According to Wächtershäuser's "Iron-Sulfur-World" one major requirement for the development of life on the prebiotic Earth is compartmentalization. Vesicles spontaneously formed from amphiphilic components containing a specific set of molecules including sulfide minerals may have lead to the first autotrophic prebiotic units. The iron sulfide minerals may have been formed by geological conversions in the environment of deep-sea volcanos (black smokers), which can be observed even today. Wächtershäuser postulated the evolution of chemical pathways as fundamentals of the origin of life on earth. In contrast to the classical Miller-Urey experiment, depending on external energy sources, the "Iron-Sulfur-World" is based on the catalytic and energy reproducing redox system FeS+H2S-->FeS2+H2. The energy release out of this redox reaction (∆RG°=-38 kJ/mol, pH 0) could be the cause for the subsequent synthesis of complex organic molecules and the precondition for the development of more complex units similar to cells known today. Here we show the possibility for precipitating iron sulfide inside vesicles composed of amphiphilic block-copolymers as a model system for a first prebiotic unit. Our findings could be an indication for a chemoautotrophic FeS based origin of life.

A diesel fuel processor for fuel-cell-based auxiliary power unit applications

NASA Astrophysics Data System (ADS)

Samsun, Remzi Can; Krekel, Daniel; Pasel, Joachim; Prawitz, Matthias; Peters, Ralf; Stolten, Detlef

2017-07-01

Producing a hydrogen-rich gas from diesel fuel enables the efficient generation of electricity in a fuel-cell-based auxiliary power unit. In recent years, significant progress has been achieved in diesel reforming. One issue encountered is the stable operation of water-gas shift reactors with real reformates. A new fuel processor is developed using a commercial shift catalyst. The system is operated using optimized start-up and shut-down strategies. Experiments with diesel and kerosene fuels show slight performance drops in the shift reactor during continuous operation for 100 h. CO concentrations much lower than the target value are achieved during system operation in auxiliary power unit mode at partial loads of up to 60%. The regeneration leads to full recovery of the shift activity. Finally, a new operation strategy is developed whereby the gas hourly space velocity of the shift stages is re-designed. This strategy is validated using different diesel and kerosene fuels, showing a maximum CO concentration of 1.5% at the fuel processor outlet under extreme conditions, which can be tolerated by a high-temperature PEFC. The proposed operation strategy solves the issue of strong performance drop in the shift reactor and makes this technology available for reducing emissions in the transportation sector.

Identification of different geologic units using fuzzy constrained resistivity tomography

NASA Astrophysics Data System (ADS)

Singh, Anand; Sharma, S. P.

2018-01-01

Different geophysical inversion strategies are utilized as a component of an interpretation process that tries to separate geologic units based on the resistivity distribution. In the present study, we present the results of separating different geologic units using fuzzy constrained resistivity tomography. This was accomplished using fuzzy c means, a clustering procedure to improve the 2D resistivity image and geologic separation within the iterative minimization through inversion. First, we developed a Matlab-based inversion technique to obtain a reliable resistivity image using different geophysical data sets (electrical resistivity and electromagnetic data). Following this, the recovered resistivity model was converted into a fuzzy constrained resistivity model by assigning the highest probability value of each model cell to the cluster utilizing fuzzy c means clustering procedure during the iterative process. The efficacy of the algorithm is demonstrated using three synthetic plane wave electromagnetic data sets and one electrical resistivity field dataset. The presented approach shows improvement on the conventional inversion approach to differentiate between different geologic units if the correct number of geologic units will be identified. Further, fuzzy constrained resistivity tomography was performed to examine the augmentation of uranium mineralization in the Beldih open cast mine as a case study. We also compared geologic units identified by fuzzy constrained resistivity tomography with geologic units interpreted from the borehole information.

A novel fluorescein-based "turn-on" probe for the detection of hydrazine and its application in living cells

NASA Astrophysics Data System (ADS)

Xu, Wen-Zhi; Liu, Wei-Yan; Zhou, Ting-Ting; Yang, Yu-Tao; Li, Wei

2018-03-01

We constructed a novel probe for hydrazine detection based on ICT and PET mechanism. Phthalimide and acetyl ester groups were used as the recognition units. Addition of hydrazine produced a turn-on fluorescence at 525 nm along with the fluorescent color change from dark to yellow. The probe could selectively detect hydrazine over other related interfering species. The detection limit of the probe for hydrazine was calculated to be 0.057 μM which was lower than the EPA standard (0.320 μM). Furthermore, the probe could also be applied for the imaging of hydrazine in living cells.

Packaging of a large capacity magnetic bubble domain spacecraft recorder

NASA Technical Reports Server (NTRS)

Becker, F. J.; Stermer, R. L.

1977-01-01

A Solid State Spacecraft Data Recorder (SSDR), based on bubble domain technology, having a storage capacity of 10 to the 8th power bits, was designed and is being tested. The recorder consists of two memory modules each having 32 cells, each cell containing sixteen 100 kilobit serial bubble memory chips. The memory modules are interconnected to a Drive and Control Unit (DCU) module containing four microprocessors, 500 integrated circuits, a RAM core memory and two PROM's. The two memory modules and DCU are housed in individual machined aluminum frames, are stacked in brick fashion and through bolted to a base plate assembly which also houses the power supply.

Self-Assembly of a [1+1] Ionic Hexagonal Macrocycle and its Antiproliferative Activity

NASA Astrophysics Data System (ADS)

Singh, Khushwant; Gangrade, Ankit; Bhowmick, Sourav; Jana, Achintya; Mandal, Biman B.; Das, Neeladri

2018-04-01

A unique irregular hexagon was self-assembled using an organic donor clip (bearing terminal pyridyl units) and a complementary organometallic acceptor clip. The resulting metallamacrocycle was characterized by multinuclear NMR, mass spectrometry, and elemental analyses. Molecular modeling confirmed hexagonal shaped cavity for this metallamacrocycle which is a unique example of a discrete hexagonal framework self-assembled from only two building blocks. Cytotoxicity of the Pt-based acceptor tecton and the self-assembled PtII-based macrocycle was evaluated using three cancer cell lines and results were compared with cisplatin. Results confirmed a positive effect of the metallamacrocycle formation on cell growth inhibition.

Unit: Cells, Inspection Set, National Trial Print.

ERIC Educational Resources Information Center

Australian Science Education Project, Toorak, Victoria.

This trial version of a unit is the series being produced by the Australian Science Education Project provides instructions for students to prepare a variety of cell types and examine them with microscopes. It also gives some information about the variety and function of cells. The core of the unit, which all students are expected to complete,…

Fine-tuning of electronic properties in donor-acceptor conjugated polymers based on oligothiophenes

NASA Astrophysics Data System (ADS)

Imae, Ichiro; Sagawa, Hitoshi; Harima, Yutaka

2018-03-01

A novel series of donor-acceptor conjugated polymers having oligothiophenes with well-defined structures were synthesized and their optical, electrochemical, and photovoltaic properties were investigated. It was found that the absorption bands of polymers were red-shifted with increasing number of ethylenedioxy groups added to each oligothiophene unit and that their band edges reached over 1000 nm. The systematical fine-tuning of the electronic properties was achieved using the chemical structures of oligothiophene units. Photovoltaic cells based on polymer/(6,6)-phenyl C61 butyric acid methyl ester (PC61BM) exhibited power conversion efficiencies in the range from 0.004 to 1.10%, reflecting the electronic properties of the polymers.

MaxSynBio - Avenues towards creating cells from the bottom up.

PubMed

Schwille, Petra; Spatz, Joachim; Landfester, Katharina; Bodenschatz, Eberhard; Herminghaus, Stephan; Sourjik, Victor; Erb, Tobias; Bastiaens, Philippe; Lipowsky, Reinhard; Hyman, Anthony; Dabrock, Peter; Baret, Jean-Christophe; Vidakovic-Koch, Tanja; Bieling, Peter; Dimova, Rumiana; Mutschler, Hannes; Robinson, Tom; Tang, Dora; Wegner, Seraphine; Sundmacher, Kai

2018-05-11

A large Max Planck-based German research consortium ('MaxSynBio') was formed to investigate living systems from a fundamental perspective. The research program of MaxSynBio relies solely on the bottom-up approach to Synthetic Biology. MaxSynBio focuses on the detailed analysis and understanding of essential processes of life, via their modular reconstitution in minimal synthetic systems. The ultimate goal is to construct a basic living unit entirely from non-living components. The fundamental insights gained from the activities in MaxSynBio can eventually be utilized for establishing a new generation of biotechnological processes, which would be based on synthetic cell constructs that replace natural cells currently used in conventional biotechnology. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficacy of education followed by computerized provider order entry with clinician decision support to reduce red blood cell utilization.

PubMed

Zuckerberg, Gabriel S; Scott, Andrew V; Wasey, Jack O; Wick, Elizabeth C; Pawlik, Timothy M; Ness, Paul M; Patel, Nishant D; Resar, Linda M S; Frank, Steven M

2015-07-01

Two necessary components of a patient blood management program are education regarding evidence-based transfusion guidelines and computerized provider order entry (CPOE) with clinician decision support (CDS). This study examines changes in red blood cell (RBC) utilization associated with each of these two interventions. We reviewed 5 years of blood utilization data (2009-2013) for 70,118 surgical patients from 10 different specialty services at a tertiary care academic medical center. Three distinct periods were compared: 1) before blood management, 2) education alone, and 3) education plus CPOE. Changes in RBC unit utilization were assessed over the three periods stratified by surgical service. Cost savings were estimated based on RBC acquisition costs. For all surgical services combined, RBC utilization decreased by 16.4% with education alone (p = 0.001) and then changed very little (2.5% increase) after subsequent addition of CPOE (p = 0.64). When we compared the period of education plus CPOE to the pre-blood management period, the overall decrease was 14.3% (p = 0.008; 2102 fewer RBC units/year, or a cost avoidance of $462,440/year). Services with the highest massive transfusion rates (≥10 RBC units) exhibited the least reduction in RBC utilization. Adding CPOE with CDS after a successful education effort to promote evidence-based transfusion practice did not further reduce RBC utilization. These findings suggest that education is an important and effective component of a patient blood management program and that CPOE algorithms may serve to maintain compliance with evidence-based transfusion guidelines. © 2015 AABB.

20170312 - In Silico Dynamics: computer simulation in a ...

EPA Pesticide Factsheets

Abstract: Utilizing cell biological information to predict higher order biological processes is a significant challenge in predictive toxicology. This is especially true for highly dynamical systems such as the embryo where morphogenesis, growth and differentiation require precisely orchestrated interactions between diverse cell populations. In patterning the embryo, genetic signals setup spatial information that cells then translate into a coordinated biological response. This can be modeled as ‘biowiring diagrams’ representing genetic signals and responses. Because the hallmark of multicellular organization resides in the ability of cells to interact with one another via well-conserved signaling pathways, multiscale computational (in silico) models that enable these interactions provide a platform to translate cellular-molecular lesions perturbations into higher order predictions. Just as ‘the Cell’ is the fundamental unit of biology so too should it be the computational unit (‘Agent’) for modeling embryogenesis. As such, we constructed multicellular agent-based models (ABM) with ‘CompuCell3D’ (www.compucell3d.org) to simulate kinematics of complex cell signaling networks and enable critical tissue events for use in predictive toxicology. Seeding the ABMs with HTS/HCS data from ToxCast demonstrated the potential to predict, quantitatively, the higher order impacts of chemical disruption at the cellular or bioche

In Silico Dynamics: computer simulation in a Virtual Embryo ...

EPA Pesticide Factsheets

Abstract: Utilizing cell biological information to predict higher order biological processes is a significant challenge in predictive toxicology. This is especially true for highly dynamical systems such as the embryo where morphogenesis, growth and differentiation require precisely orchestrated interactions between diverse cell populations. In patterning the embryo, genetic signals setup spatial information that cells then translate into a coordinated biological response. This can be modeled as ‘biowiring diagrams’ representing genetic signals and responses. Because the hallmark of multicellular organization resides in the ability of cells to interact with one another via well-conserved signaling pathways, multiscale computational (in silico) models that enable these interactions provide a platform to translate cellular-molecular lesions perturbations into higher order predictions. Just as ‘the Cell’ is the fundamental unit of biology so too should it be the computational unit (‘Agent’) for modeling embryogenesis. As such, we constructed multicellular agent-based models (ABM) with ‘CompuCell3D’ (www.compucell3d.org) to simulate kinematics of complex cell signaling networks and enable critical tissue events for use in predictive toxicology. Seeding the ABMs with HTS/HCS data from ToxCast demonstrated the potential to predict, quantitatively, the higher order impacts of chemical disruption at the cellular or biochemical level. This is demonstrate

Geologic framework for the national assessment of carbon dioxide storage resources

USGS Publications Warehouse

Warwick, Peter D.; Corum, Margo D.

2012-01-01

The 2007 Energy Independence and Security Act (Public Law 110–140) directs the U.S. Geological Survey (USGS) to conduct a national assessment of potential geologic storage resources for carbon dioxide (CO2) and to consult with other Federal and State agencies to locate the pertinent geological data needed for the assessment. The geologic sequestration of CO2 is one possible way to mitigate its effects on climate change. The methodology used for the national CO2 assessment (Open-File Report 2010-1127; http://pubs.usgs.gov/of/2010/1127/) is based on previous USGS probabilistic oil and gas assessment methodologies. The methodology is non-economic and intended to be used at regional to subbasinal scales. The operational unit of the assessment is a storage assessment unit (SAU), composed of a porous storage formation with fluid flow and an overlying sealing unit with low permeability. Assessments are conducted at the SAU level and are aggregated to basinal and regional results. This report identifies and contains geologic descriptions of SAUs in separate packages of sedimentary rocks within the assessed basin and focuses on the particular characteristics, specified in the methodology, that influence the potential CO2 storage resource in those SAUs. Specific descriptions of the SAU boundaries as well as their sealing and reservoir units are included. Properties for each SAU such as depth to top, gross thickness, net porous thickness, porosity, permeability, groundwater quality, and structural reservoir traps are provided to illustrate geologic factors critical to the assessment. Although assessment results are not contained in this report, the geologic information included here will be employed, as specified in the methodology, to calculate a statistical Monte Carlo-based distribution of potential storage space in the various SAUs. Figures in this report show SAU boundaries and cell maps of well penetrations through the sealing unit into the top of the storage formation. Wells sharing the same well borehole are treated as a single penetration. Cell maps show the number of penetrating wells within one square mile and are derived from interpretations of incompletely attributed well data, a digital compilation that is known not to include all drilling. The USGS does not expect to know the location of all wells and cannot guarantee the amount of drilling through specific formations in any given cell shown on cell maps.

Finite-size correction scheme for supercell calculations in Dirac-point two-dimensional materials.

PubMed

Rocha, C G; Rocha, A R; Venezuela, P; Garcia, J H; Ferreira, M S

2018-06-19

Modern electronic structure calculations are predominantly implemented within the super cell representation in which unit cells are periodically arranged in space. Even in the case of non-crystalline materials, defect-embedded unit cells are commonly used to describe doped structures. However, this type of computation becomes prohibitively demanding when convergence rates are sufficiently slow and may require calculations with very large unit cells. Here we show that a hitherto unexplored feature displayed by several 2D materials may be used to achieve convergence in formation- and adsorption-energy calculations with relatively small unit-cell sizes. The generality of our method is illustrated with Density Functional Theory calculations for different 2D hosts doped with different impurities, all of which providing accuracy levels that would otherwise require enormously large unit cells. This approach provides an efficient route to calculating the physical properties of 2D systems in general but is particularly suitable for Dirac-point materials doped with impurities that break their sublattice symmetry.

V-band electronically reconfigurable metamaterial

NASA Astrophysics Data System (ADS)

Radisic, Vesna; Hester, Jimmy G.; Nguyen, Vinh N.; Caira, Nicholas W.; DiMarzio, Donald; Hilgeman, Theodore; Larouche, Stéphane; Kaneshiro, Eric; Gutierrez-Aitken, Augusto

2017-04-01

In this work, we report on a reconfigurable V-band metamaterial fabricated using an InP heterojunction bipolar transistor production process. As designed and fabricated, the implementation uses complementary split ring resonators (cSRRs) and Schottky diodes in both single unit cell and three unit cell monolithic microwave integrated circuits. Each unit cell has two diodes embedded within the gaps of the cSRRs. Reconfigurability is achieved by applying an external bias that turns the diodes on and off, which effectively controls the resonant property of the structure. In order to measure the metamaterial properties, the unit cells are fed and followed by transmission lines. Measured data show good agreement with simulations and demonstrate that the metamaterial structure exhibits resonance at around 65 GHz that can be switched on and off. The three-unit cell transmission line metamaterial shows a deeper resonance and a larger phase change than a single cell, as expected. These are the first reported reconfigurable metamaterials operating at the V-band using the InP high speed device fabrication process.

[The cell theory. Progress in studies on cell-cell communications].

PubMed

Brodskiĭ, V Ia

2009-01-01

Current data confirm the fundamental statement of the cell theory concerning the cell reproduction in a series of generations (omnis cellula e cellula). Cell communities or ensembles integrated by the signaling systems established in prokaryotes and protists and functioning in multicellular organisms including mammals are considered as the structural and functional unit of a multicellular organism. The cell is an elementary unit of life and basis of organism development and functioning. At the same time, the adult organism is not just a totality of cells. Multinucleated cells in some tissues, syncytial structure, and structural-functional units of organs are adaptations for optimal functioning of the multicellular organism and manifestations of cell-cell communications in development and definitive functioning. The cell theory was supplemented and developed by studies on cell-cell communications; however, these studies do not question the main generalizations of the theory.

From microbial communities to cells

NASA Technical Reports Server (NTRS)

Margulis, L.

1985-01-01

The eukraotic cell, the unit of structure of protoctists, plants, fungi, and animals, is not at all homologous to prokaryotic cells. Instead the eukaryotic cell is homologous to communities of microorganisms such as those of the sulfuretum. This research is based on the hypothesis that at least four different interacting community members entered the original associations that, when stabilized, led to the emergence of eukaryotic cells. These are: (1) host nucleocytoplasm (thermoplasma like archaebacteria); (2) mitochrondria (paracoccus or bdellovibryo like respiring bacteria; and (3) plastids (cyanobacteria) and undulipodia. Tubulin like protein was found in the free living spirochete Spirochaeta bajacaliforniensis and in several other spirochetes. The amino acid sequence was to see if the spirochete protein is homologous to the tubulin of undulipodial and mitotic spindle microtubules.

Design and optimization of non-clogging counter-flow microconcentrator for enriching epidermoid cervical carcinoma cells.

PubMed

Tran-Minh, Nhut; Dong, Tao; Su, Qianhua; Yang, Zhaochu; Jakobsen, Henrik; Karlsen, Frank

2011-02-01

Clogging failure is common for microfilters in living cells concentration; for instance, the CaSki Cell-lines (Epidermoid cervical carcinoma cells) utilizing the flat membrane structure. In order to avoid the clogging, counter-flow concentration units with turbine blade-like micropillar are proposed in microconcentrator design. Due to the unusual geometrical-profiles and extraordinary microfluidic performance, the cells blocking does not occur even at permeate entrances. A counter-flow microconcentrator was designed, with both processing layer and collecting layer arranged in terms of the fractal based honeycomb structure. The device was optimized by coupling Artificial Neuron Network (ANN) and Computational Fluid Dynamics (CFD). The excellent concentration ratio of a final microconcentrator was presented in numerical results.

Efficient Lead-Free Solar Cells Based on Hollow {en}MASnI3 Perovskites.

PubMed

Ke, Weijun; Stoumpos, Constantinos C; Spanopoulos, Ioannis; Mao, Lingling; Chen, Michelle; Wasielewski, Michael R; Kanatzidis, Mercouri G

2017-10-18

Tin-based perovskites have very comparable electronic properties to lead-based perovskites and are regarded as possible lower toxicity alternates for solar cell applications. However, the efficiency of tin-based perovskite solar cells is still low and they exhibit poor air stability. Here, we report lead-free tin-based solar cells with greatly enhanced performance and stability using so-called "hollow" ethylenediammonium and methylammonium tin iodide ({en}MASnI 3 ) perovskite as absorbers. Our results show that en can improve the film morphology and most importantly can serve as a new cation to be incorporated into the 3D MASnI 3 lattice. When the cation of en becomes part of the 3D structure, a high density of SnI 2 vacancies is created resulting in larger band gap, larger unit cell volume, lower trap-state density, and much longer carrier lifetime compared to classical MASnI 3 . The best-performing {en}MASnI 3 solar cell has achieved a high efficiency of 6.63% with an open circuit voltage of 428.67 mV, a short-circuit current density of 24.28 mA cm -2 , and a fill factor of 63.72%. Moreover, the {en}MASnI 3 device shows much better air stability than the neat MASnI 3 device. Comparable performance is also achieved for cesium tin iodide solar cells with en loading, demonstrating the broad scope of this approach.

Radiolabeled Adenoviral Sub-unit Proteins for Molecular Imaging and Therapeutic Applications in Oncology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Srivastava, S.; Meinken, G.; Springer, K. Awasthi, V.

2004-10-06

The objective of this project was to develop and optimize new ligand systems, based on adenoviral vectors (intact adenovirus, adeno-viral fiber protein, and the knob protein), for delivering suitable radionuclides into tumor cells for molecular imaging and combined gene/radionuclide therapy of cancer.

In-vitro Cell Culture and Real-time Reverse Transcriptase PCR-based Assays to Detect Infective Toxoplas gondii Oocysts

EPA Science Inventory

Toxoplasma gondii is an obligate intracellular, apicomplexan parasite that infects humans. It is ubiquitous in nature and seroprevalence in the United States and in Europe ranges from 25->70%. Although typically associated with causing foodborne outbreaks, recent studies in Canad...

Long-Term Quality Control Program Plan for Cord Blood Banks in Korea: A Pilot Study for Cryopreservation Stability.

PubMed

Seo, Soo Hyun; Shin, Sue; Roh, Eun Youn; Song, Eun Young; Oh, Sohee; Kim, Byoung Jae; Yoon, Jong Hyun

2017-03-01

Maintaining the quality of cryopreserved cord blood is crucial. In this pilot study, we describe the results of the internal quality control program for a cord blood bank thus far. Donated cord blood units unsuitable for transplantation were selected for internal quality control once a month. One unit of cord blood, aliquoted into 21 capillaries, was cryopreserved and thawed annually to analyze the total nucleated cell count, CD34⁺ cell count, cell viability test, and colony-forming units assay. No significant differences in the variables (total nucleated cell count, cell viability, CD34⁺ cell count) were observed between samples cryopreserved for one and two years. Upon comparing the variables before cryopreservation and post thawing with the capillaries of one year of storage, cell viability and CD34⁺ cell counts decreased significantly. The use of cord blood samples in capillaries, which can be easily stored for a long period, was similar to the methods used for testing segments attached to the cord blood unit. The results of this study may be useful for determining the period during which the quality of cryopreserved cord blood units used for transplantation is maintained.

Long-Term Quality Control Program Plan for Cord Blood Banks in Korea: A Pilot Study for Cryopreservation Stability

PubMed Central

Seo, Soo Hyun; Shin, Sue; Roh, Eun Youn; Song, Eun Young; Oh, Sohee; Kim, Byoung Jae

2017-01-01

Background Maintaining the quality of cryopreserved cord blood is crucial. In this pilot study, we describe the results of the internal quality control program for a cord blood bank thus far. Methods Donated cord blood units unsuitable for transplantation were selected for internal quality control once a month. One unit of cord blood, aliquoted into 21 capillaries, was cryopreserved and thawed annually to analyze the total nucleated cell count, CD34+ cell count, cell viability test, and colony-forming units assay. Results No significant differences in the variables (total nucleated cell count, cell viability, CD34+ cell count) were observed between samples cryopreserved for one and two years. Upon comparing the variables before cryopreservation and post thawing with the capillaries of one year of storage, cell viability and CD34+ cell counts decreased significantly. The use of cord blood samples in capillaries, which can be easily stored for a long period, was similar to the methods used for testing segments attached to the cord blood unit. Conclusions The results of this study may be useful for determining the period during which the quality of cryopreserved cord blood units used for transplantation is maintained. PMID:28028998

Hydrogen ion dynamics in human red blood cells

PubMed Central

Swietach, Pawel; Tiffert, Teresa; Mauritz, Jakob M A; Seear, Rachel; Esposito, Alessandro; Kaminski, Clemens F; Lew, Virgilio L; Vaughan-Jones, Richard D

2010-01-01

Our understanding of pH regulation within red blood cells (RBCs) has been inferred mainly from indirect experiments rather than from in situ measurements of intracellular pH (pHi). The present work shows that carboxy-SNARF-1, a pH fluorophore, when used with confocal imaging or flow cytometry, reliably reports pHi in individual, human RBCs, provided intracellular fluorescence is calibrated using a ‘null-point’ procedure. Mean pHi was 7.25 in CO2/HCO3−-buffered medium and 7.15 in Hepes-buffered medium, and varied linearly with extracellular pH (slope of 0.77). Intrinsic (non-CO2/HCO3−-dependent) buffering power, estimated in the intact cell (85 mmol (l cell)−1 (pH unit)−1 at resting pHi), was somewhat higher than previous estimates from cell lysates (50–70 mmol (l cell)−1 (pH unit)−1). Acute displacement of pHi (superfusion of weak acids/bases) triggered rapid pHi recovery. This was mediated via membrane Cl−/HCO3− exchange (the AE1 gene product), irrespective of whether recovery was from an intracellular acid or base load, and with no evident contribution from other transporters such as Na+/H+ exchange. H+-equivalent flux through AE1 was a linear function of [H+]i and reversed at resting pHi, indicating that its activity is not allosterically regulated by pHi, in contrast to other AE isoforms. By simultaneously monitoring pHi and markers of cell volume, a functional link between membrane ion transport, volume and pHi was demonstrated. RBC pHi is therefore tightly regulated via AE1 activity, but modulated during changes of cell volume. A comparable volume–pHi link may also be important in other cell types expressing anion exchangers. Direct measurement of pHi should be useful in future investigations of RBC physiology and pathology. PMID:20962000

MEMS technologies for epiretinal stimulation of the retina

NASA Astrophysics Data System (ADS)

Mokwa, W.

2004-09-01

It has been shown that electrical stimulation of retinal ganglion cells yields visual sensations. Therefore, a retina implant for blind humans suffering from retinitis pigmentosa based on this concept seems to be feasible. In Germany, there are two projects funded by the government working on different approaches namely the subretinal and the epiretinal approaches. This paper describes the epiretinal approach for such a system. The extraocular part of this system records visual images. The images are transformed by a neural net into corresponding signals for stimulation of the retinal ganglion cells. These signals are transmitted to a receiver unit of an intraocular implant, the retina stimulator. Integrated circuitry of this unit decodes the signals and transfers the data to a stimulation circuitry that selects stimulation electrodes placed onto the retina and generates current pulses to the electrodes. By this, action potentials in retinal ganglion cells are evoked, causing a visual sensation. This paper concentrates on the MEMS part of this implant.

A Series of Zn(II) Terpyridine-Based Nitrate Complexes as Two-Photon Fluorescent Probe for Identifying Apoptotic and Living Cells via Subcellular Immigration.

PubMed

Liu, Dandan; Zhang, Mingzhu; Du, Wei; Hu, Lei; Li, Fei; Tian, Xiaohe; Wang, Aidong; Zhang, Qiong; Zhang, Zhongping; Wu, Jieying; Tian, Yupeng

2018-06-19

Two-photon active probe to label apoptotic cells plays a significant role in biological systems. However, discrimination of live/apoptotic cells at subcellular level under microscopy remains unachieved. Here, three novel Zn(II) terpyridine-based nitrate complexes (C1-C3) containing different pull/push units were designed. The structures of the ligands and their corresponding Zn(II) complexes were confirmed by single-crystal X-ray diffraction analysis. On the basis of the comprehensive comparison, C3 had a suitable two-photon absorption cross section in the near-infrared wavelength and good biocompatibility. Under two-photon confocal microscopy and transmission electron microscopy, it is found that C3 could target mitochondria in living cells but immigrate into the nucleolus during the apoptotic process. This dual-functional probe (C3) not only offers a valuable image tool but also acts as an indicator for cell mortality at subcellular level in a real-time manner.

Efficiently photo-charging lithium-ion battery by perovskite solar cell

NASA Astrophysics Data System (ADS)

Xu, Jiantie; Chen, Yonghua; Dai, Liming

2015-08-01

Electric vehicles using lithium-ion battery pack(s) for propulsion have recently attracted a great deal of interest. The large-scale practical application of battery electric vehicles may not be realized unless lithium-ion batteries with self-charging suppliers will be developed. Solar cells offer an attractive option for directly photo-charging lithium-ion batteries. Here we demonstrate the use of perovskite solar cell packs with four single CH3NH3PbI3 based solar cells connected in series for directly photo-charging lithium-ion batteries assembled with a LiFePO4 cathode and a Li4Ti5O12 anode. Our device shows a high overall photo-electric conversion and storage efficiency of 7.80% and excellent cycling stability, which outperforms other reported lithium-ion batteries, lithium-air batteries, flow batteries and super-capacitors integrated with a photo-charging component. The newly developed self-chargeable units based on integrated perovskite solar cells and lithium-ion batteries hold promise for various potential applications.

Efficiently photo-charging lithium-ion battery by perovskite solar cell

PubMed Central

Xu, Jiantie; Chen, Yonghua; Dai, Liming

2015-01-01

Electric vehicles using lithium-ion battery pack(s) for propulsion have recently attracted a great deal of interest. The large-scale practical application of battery electric vehicles may not be realized unless lithium-ion batteries with self-charging suppliers will be developed. Solar cells offer an attractive option for directly photo-charging lithium-ion batteries. Here we demonstrate the use of perovskite solar cell packs with four single CH3NH3PbI3 based solar cells connected in series for directly photo-charging lithium-ion batteries assembled with a LiFePO4 cathode and a Li4Ti5O12 anode. Our device shows a high overall photo-electric conversion and storage efficiency of 7.80% and excellent cycling stability, which outperforms other reported lithium-ion batteries, lithium–air batteries, flow batteries and super-capacitors integrated with a photo-charging component. The newly developed self-chargeable units based on integrated perovskite solar cells and lithium-ion batteries hold promise for various potential applications. PMID:26311589

MSuPDA: A memory efficient algorithm for sequence alignment.

PubMed

Khan, Mohammad Ibrahim; Kamal, Md Sarwar; Chowdhury, Linkon

2015-01-16

Space complexity is a million dollar question in DNA sequence alignments. In this regards, MSuPDA (Memory Saving under Pushdown Automata) can help to reduce the occupied spaces in computer memory. Our proposed process is that Anchor Seed (AS) will be selected from given data set of Nucleotides base pairs for local sequence alignment. Quick Splitting (QS) techniques will separate the Anchor Seed from all the DNA genome segments. Selected Anchor Seed will be placed to pushdown Automata's (PDA) input unit. Whole DNA genome segments will be placed into PDA's stack. Anchor Seed from input unit will be matched with the DNA genome segments from stack of PDA. Whatever matches, mismatches or Indel, of Nucleotides will be POP from the stack under the control of control unit of Pushdown Automata. During the POP operation on stack it will free the memory cell occupied by the Nucleotide base pair.

Fused thiophene-based conjugated polymers and their use in optoelectronic devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Facchetti, Antonio; Marks, Tobin J.; Takai, Atsuro

The present teachings relate to polymeric compounds and their use as organic semiconductors in organic and hybrid optical, optoelectronic, and/or electronic devices such as photovoltaic cells, light emitting diodes, light emitting transistors, and field effect transistors. The disclosed compounds generally include as repeating units at least one annulated thienyl-vinylene-thienyl (TVT) unit and at least one other pi-conjugated unit. The annulated TVT unit can be represented by the formula: ##STR00001## where Cy.sup.1 and Cy.sup.2 can be a five- or six-membered carbocyclic ring. The annulated TVT unit can be optionally substituted at any available ring atom(s), and can be covalently linked tomore » the other pi-conjugated unit via either the thiophene rings or the carbocyclic rings Cy.sup.1 and Cy.sup.2. The other pi-conjugated unit can be a conjugated linear linker including one or more unsaturated bonds, or a conjugated cyclic linker including one or more carbocyclic and/or heterocyclic rings.« less

Hydrogen storage and integrated fuel cell assembly

DOEpatents

Gross, Karl J.

2010-08-24

Hydrogen is stored in materials that absorb and desorb hydrogen with temperature dependent rates. A housing is provided that allows for the storage of one or more types of hydrogen-storage materials in close thermal proximity to a fuel cell stack. This arrangement, which includes alternating fuel cell stack and hydrogen-storage units, allows for close thermal matching of the hydrogen storage material and the fuel cell stack. Also, the present invention allows for tailoring of the hydrogen delivery by mixing different materials in one unit. Thermal insulation alternatively allows for a highly efficient unit. Individual power modules including one fuel cell stack surrounded by a pair of hydrogen-storage units allows for distribution of power throughout a vehicle or other electric power consuming devices.

Extraction of Carbon Dioxide and Hydrogen from Seawater by an Electrochemical Acidification Cell. Part 3. Scaled-up Mobile Unit Studies (Calendar Year 2011)

DTIC Science & Technology

2012-05-30

Electrochemical Acidification Cell Part III: Scaled-up Mobile Unit Studies (Calendar Year 2011) May 30, 2012 Approved for public release; distribution is...Hydrogen from Seawater by an Electrochemical Acidification Cell Part III: Scaled-up Mobile Unit Studies (Calendar Year 2011) Heather D. Willauer, Dennis R...Unclassified Unlimited Unclassified Unlimited Unclassified Unlimited 41 Heather D. Willauer (202) 767-2673 Electrochemical acidification cell Carbon

Free-Space Measurements of Dielectrics and Three-Dimensional Periodic Metamaterials

NASA Astrophysics Data System (ADS)

Kintner, Clifford E.

This thesis presents the free-space measurements of a periodic metamaterial structure. The metamaterial unit cell consists of two dielectric sheets intersecting at 90 degrees. The dielectric is a polyetherimide-based material 0.001" thick. Each sheet has a copper capacitively-loaded loop (CLL) structure on the front and a cut-wire structure on the back. Foam material is used to support the unit cells. The unit cell repeats 40 times in the x-direction, 58 times in the y-direction and 5 times in the z-direction. The sample measures 12" x 12" x 1" in total. We use a free-space broadband system comprised of a pair of dielectric-lens horn antennas with bandwidth from 5.8 GHz to 110 GHz, which are connected to a HP PNA series network analyzer. The dielectric lenses focus the incident beam to a footprint measuring 1 wavelength by 1 wavelength. The sample holder is positioned at the focal point between the two antennas. In this work, the coefficients of transmission and reflection (the S-parameters S21 and S11) are measured at frequencies from 12.4 GHz up to 30 GHz. Simulations are used to validate the measurements, using the Ansys HFSS commercial software package on the Arkansas High Performance Computing Center cluster. The simulation results successfully validate the S-parameters measurements, in particular the amplitudes. An algorithm based on the Nicolson-Ross-Weir (NRW) method is implemented to extract the permittivity and permeability values of the metamaterial under test. The results show epsilon-negative, mu-negative and double-negative parameters within the measured frequency range.

3-D phononic crystals with ultra-wide band gaps

PubMed Central

Lu, Yan; Yang, Yang; Guest, James K.; Srivastava, Ankit

2017-01-01

In this paper gradient based topology optimization (TO) is used to discover 3-D phononic structures that exhibit ultra-wide normalized all-angle all-mode band gaps. The challenging computational task of repeated 3-D phononic band-structure evaluations is accomplished by a combination of a fast mixed variational eigenvalue solver and distributed Graphic Processing Unit (GPU) parallel computations. The TO algorithm utilizes the material distribution-based approach and a gradient-based optimizer. The design sensitivity for the mixed variational eigenvalue problem is derived using the adjoint method and is implemented through highly efficient vectorization techniques. We present optimized results for two-material simple cubic (SC), body centered cubic (BCC), and face centered cubic (FCC) crystal structures and show that in each of these cases different initial designs converge to single inclusion network topologies within their corresponding primitive cells. The optimized results show that large phononic stop bands for bulk wave propagation can be achieved at lower than close packed spherical configurations leading to lighter unit cells. For tungsten carbide - epoxy crystals we identify all angle all mode normalized stop bands exceeding 100%, which is larger than what is possible with only spherical inclusions. PMID:28233812

3-D phononic crystals with ultra-wide band gaps.

PubMed

Lu, Yan; Yang, Yang; Guest, James K; Srivastava, Ankit

2017-02-24

In this paper gradient based topology optimization (TO) is used to discover 3-D phononic structures that exhibit ultra-wide normalized all-angle all-mode band gaps. The challenging computational task of repeated 3-D phononic band-structure evaluations is accomplished by a combination of a fast mixed variational eigenvalue solver and distributed Graphic Processing Unit (GPU) parallel computations. The TO algorithm utilizes the material distribution-based approach and a gradient-based optimizer. The design sensitivity for the mixed variational eigenvalue problem is derived using the adjoint method and is implemented through highly efficient vectorization techniques. We present optimized results for two-material simple cubic (SC), body centered cubic (BCC), and face centered cubic (FCC) crystal structures and show that in each of these cases different initial designs converge to single inclusion network topologies within their corresponding primitive cells. The optimized results show that large phononic stop bands for bulk wave propagation can be achieved at lower than close packed spherical configurations leading to lighter unit cells. For tungsten carbide - epoxy crystals we identify all angle all mode normalized stop bands exceeding 100%, which is larger than what is possible with only spherical inclusions.

Aptamer-Based Dual-Functional Probe for Rapid and Specific Counting and Imaging of MCF-7 Cells.

PubMed

Yang, Bin; Chen, Beibei; He, Man; Yin, Xiao; Xu, Chi; Hu, Bin

2018-02-06

Development of multimodal detection technologies for accurate diagnosis of cancer at early stages is in great demand. In this work, we report a novel approach using an aptamer-based dual-functional probe for rapid, sensitive, and specific counting and visualization of MCF-7 cells by inductively coupled plasma-mass spectrometry (ICP-MS) and fluorescence imaging. The probe consists of a recognition unit of aptamer to catch cancer cells specifically, a fluorescent dye (FAM) moiety for fluorescence resonance energy transfer (FRET)-based "off-on" fluorescence imaging as well as gold nanoparticles (Au NPs) tag for both ICP-MS quantification and fluorescence quenching. Due to the signal amplification effect and low spectral interference of Au NPs in ICP-MS, an excellent linearity and sensitivity were achieved. Accordingly, a limit of detection of 81 MCF-7 cells and a relative standard deviation of 5.6% (800 cells, n = 7) were obtained. The dynamic linear range was 2 × 10 2 to 1.2 × 10 4 cells, and the recoveries in human whole blood were in the range of 98-110%. Overall, the established method provides quantitative and visualized information on MCF-7 cells with a simple and rapid process and paves the way for a promising strategy for biomedical research and clinical diagnostics.

Carbonate fuel cells: Milliwatts to megawatts

NASA Astrophysics Data System (ADS)

Farooque, M.; Maru, H. C.

The carbonate fuel cell power plant is an emerging high efficiency, ultra-clean power generator utilizing a variety of gaseous, liquid, and solid carbonaceous fuels for commercial and industrial applications. The primary mover of this generator is a carbonate fuel cell. The fuel cell uses alkali metal carbonate mixtures as electrolyte and operates at ∼650 °C. Corrosion of the cell hardware and stability of the ceramic components have been important design considerations in the early stages of development. The material and electrolyte choices are founded on extensive fundamental research carried out around the world in the 60s and early 70s. The cell components were developed in the late 1970s and early 1980s. The present day carbonate fuel cell construction employs commonly available stainless steels. The electrodes are based on nickel and well-established manufacturing processes. Manufacturing process development, scale-up, stack tests, and pilot system tests dominated throughout the 1990s. Commercial product development efforts began in late 1990s leading to prototype field tests beginning in the current decade leading to commercial customer applications. Cost reduction has been an integral part of the product effort. Cost-competitive product designs have evolved as a result. Approximately half a dozen teams around the world are pursuing carbonate fuel cell product development. The power plant development efforts to date have mainly focused on several hundred kW (submegawatt) to megawatt-class plants. Almost 40 submegawatt units have been operating at customer sites in the US, Europe, and Asia. Several of these units are operating on renewable bio-fuels. A 1 MW unit is operating on the digester gas from a municipal wastewater treatment plant in Seattle, Washington (US). Presently, there are a total of approximately 10 MW capacity carbonate fuel cell power plants installed around the world. Carbonate fuel cell products are also being developed to operate on coal-derived gases, diesel, and other logistic fuels. Innovative carbonate fuel cell/turbine hybrid power plant designs promising record energy conversion efficiencies approaching 75% have also emerged. This paper will review the historical development of this unique technology from milliwatt-scale laboratory cells to present megawatt-scale commercial power plants.

Dancing Styles of Collective Cell Migration: Image-Based Computational Analysis of JRAB/MICAL-L2.

PubMed

Sakane, Ayuko; Yoshizawa, Shin; Yokota, Hideo; Sasaki, Takuya

2018-01-01

Collective cell migration is observed during morphogenesis, angiogenesis, and wound healing, and this type of cell migration also contributes to efficient metastasis in some kinds of cancers. Because collectively migrating cells are much better organized than a random assemblage of individual cells, there seems to be a kind of order in migrating clusters. Extensive research has identified a large number of molecules involved in collective cell migration, and these factors have been analyzed using dramatic advances in imaging technology. To date, however, it remains unclear how myriad cells are integrated as a single unit. Recently, we observed unbalanced collective cell migrations that can be likened to either precision dancing or awa-odori , Japanese traditional dancing similar to the style at Rio Carnival, caused by the impairment of the conformational change of JRAB/MICAL-L2. This review begins with a brief history of image-based computational analyses on cell migration, explains why quantitative analysis of the stylization of collective cell behavior is difficult, and finally introduces our recent work on JRAB/MICAL-L2 as a successful example of the multidisciplinary approach combining cell biology, live imaging, and computational biology. In combination, these methods have enabled quantitative evaluations of the "dancing style" of collective cell migration.

What do Cells Really Look Like? An Inquiry into Students' Difficulties in Visualising a 3-D Biological Cell and Lessons for Pedagogy

NASA Astrophysics Data System (ADS)

Vijapurkar, Jyotsna; Kawalkar, Aisha; Nambiar, Priya

2014-04-01

In our explorations of students' concepts in an inquiry science classroom with grade 6 students from urban schools in India, we uncovered a variety of problems in their understanding of biological cells as structural and functional units of living organisms. In particular, we found not only that they visualised the cell as a two-dimensional (2-D) structure, instead of a closed three-dimensional (3-D) functional unit, but that they had a strong resistance to changing their 2-D conception to a 3-D one. Based on analyses of students' oral as well as written descriptions of cells in the classroom, and of models they made of the cell, we were able to identify the causes of students' difficulties in correctly visualising the cell. These insights helped us design a pedagogy involving guided discussions and activities that challenges students' 2-D conceptions of the cell. The activities entail very simple, low-cost, easily doable techniques to help students visualise the cell and to understand that it would not be able to function if its structure were 2-D. We also present the results of our investigations of conceptions of grade 7 students and biology undergraduates, revealing that the incorrect 2-D mental model can persist right up to the college level if it is not explicitly addressed. The classroom interactions described in this study illustrate how students' ideas can be probed and addressed in the classroom using pedagogical action research.

Bioengineered Renal Cell Therapy Device for Clinical Translation

PubMed Central

Pino, Christopher J.; Westover, Angela J.; Buffington, Deborah A.; Humes, H. David

2016-01-01

The Bioartificial Renal Epithelial Cell System (BRECS), is a cell-based device to treat acute kidney injury through renal cell therapy from an extracorporeal circuit. To enable widespread implementation of cell therapy, the BRECS was designed to be cryopreserved as a complete device, cryostored, cryoshipped to an end-use site, thawed as a complete device, and employed in a therapeutic extracorporeal hemofiltration circuit. This strategy overcomes storage and distribution issues that have been previous barriers to cell therapy. Previous BRECS housings produced by Computer Numerical Control (CNC) machining, a slow process taking hours to produce one bioreactor, was also prohibitively expensive (>$600/CNC-BRECS); major obstacles to mass production. The goal of this study was to produce a BRECS to be mass produced by injection molding (IM-BRECS), decreasing cost (<$20/unit) and improving manufacturing speed (hundreds of units/hr), while maintaining the same cell therapy function as the previous CNC-BRECS, first evaluated through prototypes produced by stereolithography (SLA-BRECS). The finalized IM-BRECS design had a significantly lower fill volume (10 mL), mass (49 g) and footprint (8.5 cm×8.5 cm×1.5 cm), and was demonstrated to outperform the previous BRECS designs with respect to heat transfer, significantly improving control of cooling during cryopreservation and reducing thaw times during warming. During in vitro culture, IM-BRECS performed similarly to previous CNC-BRECS with respect to cell metabolic activity (lactate production, oxygen consumption and glutathione metabolism) and amount of cells supported. PMID:27922886

Effect of the orthoquinone moiety in 9,10-phenanthrenequinone on its ability to induce apoptosis in HCT-116 and HL-60 cells.

PubMed

Hatae, Noriyuki; Nakamura, Jun; Okujima, Tetsuo; Ishikura, Minoru; Abe, Takumi; Hibino, Satoshi; Choshi, Tominari; Okada, Chiaki; Yamada, Hiroko; Uno, Hidemitsu; Toyota, Eiko

2013-08-15

9,10-Phenanthrenequinone (9,10-PQ) is one of the most abundant quinones among diesel exhaust particulates. Recent data have suggested that quinones induce apoptosis in immune, epithelial and tumor cells, leading to respirator illness; however, the mechanisms by which quinones induce apoptosis and the structure required for this remain unknown. We studied the antitumor activity of 9,10-PQ analogs against two human tumor cell lines, HCT-116 colon tumor cells and HL-60 promyelocytic leukemia cells. The loss of the cis-orthoquinone unit in 9,10-PQ abrogated its ability to induce apoptosis in the two tumor cell lines, and the LC50 values of these analogs were indicated over 10 μM. An analog of 9,10-PQ in which the biaryl unit had been deleted displayed a reduced ability to induce tumor cell apoptosis, while the analogs 1,10-phenanthroline-5,6-dione (9) and pyrene-4,5-dione (10), which also had modified biaryl units, exhibited increased tumor cell apoptotic activity. The cis-orthoquinone unit in 9,10-PQ was identified as essential for its ability to induce apoptosis in tumor cells, and its biaryl unit is also considered to influence orthoquinone-mediated apoptotic activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

Using Cell-ID 1.4 with R for Microscope-Based Cytometry

PubMed Central

Bush, Alan; Chernomoretz, Ariel; Yu, Richard; Gordon, Andrew

2012-01-01

This unit describes a method for quantifying various cellular features (e.g., volume, total and subcellular fluorescence localization) from sets of microscope images of individual cells. It includes procedures for tracking cells over time. One purposefully defocused transmission image (sometimes referred to as bright-field or BF) is acquired to segment the image and locate each cell. Fluorescent images (one for each of the color channels to be analyzed) are then acquired by conventional wide-field epifluorescence or confocal microscopy. This method uses the image processing capabilities of Cell-ID (Gordon et al., 2007, as updated here) and data analysis by the statistical programming framework R (R-Development-Team, 2008), which we have supplemented with a package of routines for analyzing Cell-ID output. Both Cell-ID and the analysis package are open-source. PMID:23026908

Polarization splitting phenomenon of photonic crystals constructed by two-fold rotationally symmetric unit-cells

NASA Astrophysics Data System (ADS)

Yasa, U. G.; Giden, I. H.; Turduev, M.; Kurt, H.

2017-09-01

We present an intrinsic polarization splitting characteristic of low-symmetric photonic crystals (PCs) formed by unit-cells with C 2 rotational symmetry. This behavior emerges from the polarization sensitive self-collimation effect for both transverse-magnetic (TM) and transverse-electric (TE) modes depending on the rotational orientations of the unit-cell elements. Numerical analyzes are performed in both frequency and time domains for different types of square lattice two-fold rotational symmetric PC structures. At incident wavelength of λ = 1550 nm, high polarization extinction ratios with ˜26 dB (for TE polarization) and ˜22 dB (for TM polarization) are obtained with an operating bandwidth of 59 nm. Moreover, fabrication feasibilities of the designed structure are analyzed to evaluate their robustness in terms of the unit-cell orientation: for the selected PC unit-cell composition, corresponding extinction ratios for both polarizations still remain to be over 18 dB for the unit-cell rotation interval of θ = [40°-55°]. Taking all these advantages, two-fold rotationally symmetric PCs could be considered as an essential component in photonic integrated circuits for polarization control of light.

Incremental terrain processing for large digital elevation models

NASA Astrophysics Data System (ADS)

Ye, Z.

2012-12-01

Incremental terrain processing for large digital elevation models Zichuan Ye, Dean Djokic, Lori Armstrong Esri, 380 New York Street, Redlands, CA 92373, USA (E-mail: zye@esri.com, ddjokic@esri.com , larmstrong@esri.com) Efficient analyses of large digital elevation models (DEM) require generation of additional DEM artifacts such as flow direction, flow accumulation and other DEM derivatives. When the DEMs to analyze have a large number of grid cells (usually > 1,000,000,000) the generation of these DEM derivatives is either impractical (it takes too long) or impossible (software is incapable of processing such a large number of cells). Different strategies and algorithms can be put in place to alleviate this situation. This paper describes an approach where the overall DEM is partitioned in smaller processing units that can be efficiently processed. The processed DEM derivatives for each partition can then be either mosaicked back into a single large entity or managed on partition level. For dendritic terrain morphologies, the way in which partitions are to be derived and the order in which they are to be processed depend on the river and catchment patterns. These patterns are not available until flow pattern of the whole region is created, which in turn cannot be established upfront due to the size issues. This paper describes a procedure that solves this problem: (1) Resample the original large DEM grid so that the total number of cells is reduced to a level for which the drainage pattern can be established. (2) Run standard terrain preprocessing operations on the resampled DEM to generate the river and catchment system. (3) Define the processing units and their processing order based on the river and catchment system created in step (2). (4) Based on the processing order, apply the analysis, i.e., flow accumulation operation to each of the processing units, at the full resolution DEM. (5) As each processing unit is processed based on the processing order defined in (3), compare the resulting drainage pattern with the drainage pattern established at the coarser scale and adjust the drainage boundaries and rivers if necessary.

Reproduction of the FC/DFC units in nucleoli.

PubMed

Smirnov, Evgeny; Hornáček, Matúš; Kováčik, Lubomír; Mazel, Tomáš; Schröfel, Adam; Svidenská, Silvie; Skalníková, Magdalena; Bartová, Eva; Cmarko, Dušan; Raška, Ivan

2016-04-25

The essential structural components of the nucleoli, Fibrillar Centers (FC) and Dense Fibrillar Components (DFC), together compose FC/DFC units, loci of rDNA transcription and early RNA processing. In the present study we followed cell cycle related changes of these units in 2 human sarcoma derived cell lines with stable expression of RFP-PCNA (the sliding clamp protein) and GFP-RPA43 (a subunit of RNA polymerase I, pol I) or GFP-fibrillarin. Correlative light and electron microscopy analysis showed that the pol I and fibrillarin positive nucleolar beads correspond to individual FC/DFC units. In vivo observations showed that at early S phase, when transcriptionally active ribosomal genes were replicated, the number of the units in each cell increased by 60-80%. During that period the units transiently lost pol I, but not fibrillarin. Then, until the end of interphase, number of the units did not change, and their duplication was completed only after the cell division, by mid G1 phase. This peculiar mode of reproduction suggests that a considerable subset of ribosomal genes remain transcriptionally silent from mid S phase to mitosis, but become again active in the postmitotic daughter cells.

Controlling Energy Radiations of Electromagnetic Waves via Frequency Coding Metamaterials.

PubMed

Wu, Haotian; Liu, Shuo; Wan, Xiang; Zhang, Lei; Wang, Dan; Li, Lianlin; Cui, Tie Jun

2017-09-01

Metamaterials are artificial structures composed of subwavelength unit cells to control electromagnetic (EM) waves. The spatial coding representation of metamaterial has the ability to describe the material in a digital way. The spatial coding metamaterials are typically constructed by unit cells that have similar shapes with fixed functionality. Here, the concept of frequency coding metamaterial is proposed, which achieves different controls of EM energy radiations with a fixed spatial coding pattern when the frequency changes. In this case, not only different phase responses of the unit cells are considered, but also different phase sensitivities are also required. Due to different frequency sensitivities of unit cells, two units with the same phase response at the initial frequency may have different phase responses at higher frequency. To describe the frequency coding property of unit cell, digitalized frequency sensitivity is proposed, in which the units are encoded with digits "0" and "1" to represent the low and high phase sensitivities, respectively. By this merit, two degrees of freedom, spatial coding and frequency coding, are obtained to control the EM energy radiations by a new class of frequency-spatial coding metamaterials. The above concepts and physical phenomena are confirmed by numerical simulations and experiments.

A lysosome-targetable turn-on fluorescent probe for the detection of thiols in living cells based on a 1,8-naphthalimide derivative

NASA Astrophysics Data System (ADS)

Liang, Beibei; Wang, Baiyan; Ma, Qiujuan; Xie, Caixia; Li, Xian; Wang, Suiping

2018-03-01

Biological thiols, like cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), play crucial roles in biological systems and in lysosomal processes. Highly selective probes for detecting biological thiols in lysomes of living cells are rare. In this work, a lysosome-targetable turn-on fluorescent probe for the detection of thiols in living cells was designed and synthesized based on a 1,8-naphthalimide derivative. The probe has a 4-(2-aminoethyl)morpholine unit as a lysosome-targetable group and an acrylate group as the thiol recognition unit as well as a fluorescence quencher. In the absence of biothiols, the probe displayed weak fluorescence due to the photoinduced electron transfer (PET) process. Upon the addition of biothiols, the probe exhibited an enhanced fluorescence emission centered at 550 nm due to cleavage of the acrylate moiety. The probe had high selectivity toward biothiols. Moreover, the probe features fast response time, excitation in the visible region and ability of working in a wide pH range. The linear response range covers a concentration range of Cys from 1.5 × 10- 7 to 1.0 × 10- 5 mol·L- 1 and the detection limit is 6.9 × 10- 8 mol·L- 1 for Cys. The probe has been successfully applied to the confocal imaging of biothiols in lysosomes of A549 cells with low cell toxicity. Furthermore, the method was successfully applied to the determination of thiols in a complex multicomponent mixture such as human serum, which suggests our proposed method has great potential for diagnostic purposes. All of such good properties prove it can be used to monitor biothiols in lysosomes of living cells and to be a good fluorescent probe for the selective detection of thiols.

Mass-stiffness substructuring of an elastic metasurface for full transmission beam steering

NASA Astrophysics Data System (ADS)

Lee, Hyuk; Lee, Jun Kyu; Seung, Hong Min; Kim, Yoon Young

2018-03-01

The metasurface concept has a significant potential due to its novel wavefront-shaping functionalities that can be critically useful for ultrasonic and solid wave-based applications. To achieve the desired functionalities, elastic metasurfaces should cover full 2π phase shift and also acquire full transmission within subwavelength scale. However, they have not been explored much with respect to the elastic regime, because the intrinsic proportionality of mass-stiffness within the continuum elastic media causes an inevitable trade-off between abrupt phase shift and sufficient transmission. Our goal is to engineer an elastic metasurface that can realize an inverse relation between (amplified) effective mass and (weakened) stiffness in order to satisfy full 2π phase shift as well as full transmission. To achieve this goal, we propose a continuum elastic metasurface unit cell that is decomposed into two substructures, namely a mass-tuning substructure with a local dipolar resonator and a stiffness-tuning substructure composed of non-resonant multiply-perforated slits. We demonstrate analytically, numerically, and experimentally that this unique substructured unit cell can satisfy the required phase shift with high transmission. The substructuring enables independent tuning of the elastic properties over a wide range of values. We use a mass-spring model of the proposed continuum unit cell to investigate the working mechanism of the proposed metasurface. With the designed metasurface consisting of substructured unit cells embedded in an aluminum plate, we demonstrate that our metasurface can successfully realize anomalous steering and focusing of in-plane longitudinal ultrasonic beams. The proposed substructuring concept is expected to provide a new principle for the design of general elastic metasurfaces that can be used to efficiently engineer arbitrary wave profiles.

Identification of ER Proteins Involved in the Functional Organisation of the Early Secretory Pathway in Drosophila Cells by a Targeted RNAi Screen

PubMed Central

Kondylis, Vangelis; Tang, Yang; Fuchs, Florian; Boutros, Michael; Rabouille, Catherine

2011-01-01

Background In Drosophila, the early secretory apparatus comprises discrete paired Golgi stacks in close proximity to exit sites from the endoplasmic reticulum (tER sites), thus forming tER-Golgi units. Although many components involved in secretion have been identified, the structural components sustaining its organisation are less known. Here we set out to identify novel ER resident proteins involved in the of tER-Golgi unit organisation. Results To do so, we designed a novel screening strategy combining a bioinformatics pre-selection with an RNAi screen. We first selected 156 proteins exhibiting known or related ER retention/retrieval signals from a list of proteins predicted to have a signal sequence. We then performed a microscopy-based primary and confirmation RNAi screen in Drosophila S2 cells directly scoring the organisation of the tER-Golgi units. We identified 49 hits, most of which leading to an increased number of smaller tER-Golgi units (MG for “more and smaller Golgi”) upon depletion. 16 of them were validated and characterised, showing that this phenotype was not due to an inhibition in secretion, a block in G2, or ER stress. Interestingly, the MG phenotype was often accompanied by an increase in the cell volume. Out of 6 proteins, 4 were localised to the ER. Conclusions This work has identified novel proteins involved in the organisation of the Drosophila early secretory pathway. It contributes to the effort of assigning protein functions to gene annotation in the secretory pathway, and analysis of the MG hits revealed an enrichment of ER proteins. These results suggest a link between ER localisation, aspects of cell metabolism and tER-Golgi structural organisation. PMID:21383842

Identification of ER proteins involved in the functional organisation of the early secretory pathway in Drosophila cells by a targeted RNAi screen.

PubMed

Kondylis, Vangelis; Tang, Yang; Fuchs, Florian; Boutros, Michael; Rabouille, Catherine

2011-02-23

In Drosophila, the early secretory apparatus comprises discrete paired Golgi stacks in close proximity to exit sites from the endoplasmic reticulum (tER sites), thus forming tER-Golgi units. Although many components involved in secretion have been identified, the structural components sustaining its organisation are less known. Here we set out to identify novel ER resident proteins involved in the of tER-Golgi unit organisation. To do so, we designed a novel screening strategy combining a bioinformatics pre-selection with an RNAi screen. We first selected 156 proteins exhibiting known or related ER retention/retrieval signals from a list of proteins predicted to have a signal sequence. We then performed a microscopy-based primary and confirmation RNAi screen in Drosophila S2 cells directly scoring the organisation of the tER-Golgi units. We identified 49 hits, most of which leading to an increased number of smaller tER-Golgi units (MG for "more and smaller Golgi") upon depletion. 16 of them were validated and characterised, showing that this phenotype was not due to an inhibition in secretion, a block in G2, or ER stress. Interestingly, the MG phenotype was often accompanied by an increase in the cell volume. Out of 6 proteins, 4 were localised to the ER. This work has identified novel proteins involved in the organisation of the Drosophila early secretory pathway. It contributes to the effort of assigning protein functions to gene annotation in the secretory pathway, and analysis of the MG hits revealed an enrichment of ER proteins. These results suggest a link between ER localisation, aspects of cell metabolism and tER-Golgi structural organisation.

Bootstrapping a Sustainable North American PEM Fuel Cell Industry: Could a Federal Acquisition Program Make a Difference?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greene, David L; Duleep, Dr. K. G.

2008-10-01

The North American Proton Exchange Membrane (PEM) fuel cell industry may be at a critical juncture. A large-scale market for automotive fuel cells appears to be several years away and in any case will require a long-term, coordinated commitment by government and industry to insure the co-evolution of hydrogen infrastructure and fuel cell vehicles (Greene et al., 2008). The market for non-automotive PEM fuel cells, on the other hand, may be much closer to commercial viability (Stone, 2006). Cost targets are less demanding and manufacturers appear to be close, perhaps within a factor of two, of meeting them. Hydrogen supplymore » is a significant obstacle to market acceptance but may not be as great a barrier as it is for hydrogen-powered vehicles due to the smaller quantities of hydrogen required. PEM fuel cells appear to be potentially competitive in two markets: (1) Backup power (BuP) supply, and (2) electrically-powered MHE (Mahadevan et al., 2007a, 2007b). There are several Original Equipment Manufacturers (OEMs) of PEM fuel cell systems for these applications but production levels have been quite low (on the order of 100-200 per year) and cumulative production experience is also limited (on the order of 1,000 units to date). As a consequence, costs remain above target levels and PEM fuel cell OEMs are not yet competitive in these markets. If cost targets can be reached and acceptable solutions to hydrogen supply found, a sustainable North American PEM fuel cell industry could be established. If not, the industry and its North American supply chain could disappear within a year or two. The Hydrogen Fuel Cell and Infrastructure Technologies (HFCIT) program of the U.S. Department of Energy (DOE) requested a rapid assessment of the potential for a government acquisition program to bootstrap the market for non-automotive PEM fuel cells by driving down costs via economies of scale and learning-by-doing. The six week study included in-depth interviews of three manufacturers, visits to two production facilities, review of the literature on potential markets in North America and potential federal government procurements, development of a cost model reflecting economies of scale and learning-by-doing, and estimation of the impact of federal PEM fuel cell procurements on fuel cell system costs and the evolution of private market demand. This report presents the findings of that study. Section 2 outlines the status of the industry and describes potential markets based on interviews of manufacturers and the existing literature. Section 3 describes the modeling methodology including key premises and assumptions, and presents estimates of market evolution under four scenarios: (1) Base Case with no federal government procurement program, (2) Scenario 1, an aggressive program beginning with less than 200 units procured in 2008 ramping up to more than 2,000 units in 2012, (3) Scenario 2 which is identical to Scenario 1 except that the private market is assumed to be twice as sensitive to price, and (4) Scenario 3, a delayed, smaller federal procurement program beginning in 2011 increasing to a maximum of just over 1,000 units per year in 2012. The analysis suggests that the aggressive program of Scenario 1 would likely stimulate a sustainable, competitive North American non-automotive PEM fuel cell industry. Given plausible assumptions about learning rates and scale economies, the procurements assumed in Scenario 1 appear to be sufficient to drive down costs to target levels. These findings are conditional on the evolution of acceptable hydrogen supply strategies, which were not explicitly analyzed in this study. Success is less certain under Scenarios 2 and 3, and there appears to be a strong probability that existing OEMs would not survive until 2011. In the Base Case, no program, a viable North American industry does not emerge before 2020.« less

Logistics and Capability Implications of a Bradley Fighting Vehicle with a Fuel Cell Auxiliary Power Unit

DTIC Science & Technology

2003-10-13

04ANNUAL-524 Logistics and Capability Implications of a Bradley Fighting Vehicle with a Fuel Cell Auxiliary Power Unit Joseph Conover, Harry...used or the main engines are restarted. Integration of a solid oxide fuel cell (SOFC) auxiliary power unit into a military vehicle has the...presented which show the fuel usage and capability impacts of incorporating a fuel cell APU into the electrical system of a Bradley M2A3 Diesel

Generation of Influenza Virus from Avian Cells Infected by Salmonella Carrying the Viral Genome

PubMed Central

Zhang, Xiangmin; Kong, Wei; Wanda, Soo-Young; Xin, Wei; Alamuri, Praveen; Curtiss, Roy

2015-01-01

Domestic poultry serve as intermediates for transmission of influenza A virus from the wild aquatic bird reservoir to humans, resulting in influenza outbreaks in poultry and potential epidemics/pandemics among human beings. To combat emerging avian influenza virus, an inexpensive, heat-stable, and orally administered influenza vaccine would be useful to vaccinate large commercial poultry flocks and even migratory birds. Our hypothesized vaccine is a recombinant attenuated bacterial strain able to mediate production of attenuated influenza virus in vivo to induce protective immunity against influenza. Here we report the feasibility and technical limitations toward such an ideal vaccine based on our exploratory study. Five 8-unit plasmids carrying a chloramphenicol resistance gene or free of an antibiotic resistance marker were constructed. Influenza virus was successfully generated in avian cells transfected by each of the plasmids. The Salmonella carrier was engineered to allow stable maintenance and conditional release of the 8-unit plasmid into the avian cells for recovery of influenza virus. Influenza A virus up to 107 50% tissue culture infective doses (TCID50)/ml were recovered from 11 out of 26 co-cultures of chicken embryonic fibroblasts (CEF) and Madin-Darby canine kidney (MDCK) cells upon infection by the recombinant Salmonella carrying the 8-unit plasmid. Our data prove that a bacterial carrier can mediate generation of influenza virus by delivering its DNA cargoes into permissive host cells. Although we have made progress in developing this Salmonella influenza virus vaccine delivery system, further improvements are necessary to achieve efficient virus production, especially in vivo. PMID:25742162

A ‘reader’ unit of the chemical computer

PubMed Central

Smelov, Pavel S.

2018-01-01

We suggest the main principals and functional units of the parallel chemical computer, namely, (i) a generator (which is a network of coupled oscillators) of oscillatory dynamic modes, (ii) a unit which is able to recognize these modes (a ‘reader’) and (iii) a decision-making unit, which analyses the current mode, compares it with the external signal and sends a command to the mode generator to switch it to the other dynamical regime. Three main methods of the functioning of the reader unit are suggested and tested computationally: (a) the polychronization method, which explores the differences between the phases of the generator oscillators; (b) the amplitude method which detects clusters of the generator and (c) the resonance method which is based on the resonances between the frequencies of the generator modes and the internal frequencies of the damped oscillations of the reader cells. Pro and contra of these methods have been analysed. PMID:29410852

A CpG-methylation-based assay to predict survival in clear cell renal cell carcinoma

PubMed Central

Wei, Jin-Huan; Haddad, Ahmed; Wu, Kai-Jie; Zhao, Hong-Wei; Kapur, Payal; Zhang, Zhi-Ling; Zhao, Liang-Yun; Chen, Zhen-Hua; Zhou, Yun-Yun; Zhou, Jian-Cheng; Wang, Bin; Yu, Yan-Hong; Cai, Mu-Yan; Xie, Dan; Liao, Bing; Li, Cai-Xia; Li, Pei-Xing; Wang, Zong-Ren; Zhou, Fang-Jian; Shi, Lei; Liu, Qing-Zuo; Gao, Zhen-Li; He, Da-Lin; Chen, Wei; Hsieh, Jer-Tsong; Li, Quan-Zhen; Margulis, Vitaly; Luo, Jun-Hang

2015-01-01

Clear cell renal cell carcinomas (ccRCCs) display divergent clinical behaviours. Molecular markers might improve risk stratification of ccRCC. Here we use, based on genome-wide CpG methylation profiling, a LASSO model to develop a five-CpG-based assay for ccRCC prognosis that can be used with formalin-fixed paraffin-embedded specimens. The five-CpG-based classifier was validated in three independent sets from China, United States and the Cancer Genome Atlas data set. The classifier predicts the overall survival of ccRCC patients (hazard ratio=2.96−4.82; P=3.9 × 10−6−2.2 × 10−9), independent of standard clinical prognostic factors. The five-CpG-based classifier successfully categorizes patients into high-risk and low-risk groups, with significant differences of clinical outcome in respective clinical stages and individual ‘stage, size, grade and necrosis' scores. Moreover, methylation at the five CpGs correlates with expression of five genes: PITX1, FOXE3, TWF2, EHBP1L1 and RIN1. Our five-CpG-based classifier is a practical and reliable prognostic tool for ccRCC that can add prognostic value to the staging system. PMID:26515236

Effect of Lanthanum-Strontium Cathode Current-Collecting Layer on the Performance of Anode Supported Type Planar Solid Oxide Fuel Cells

NASA Astrophysics Data System (ADS)

Park, Sun-Young; Ji, Ho-Il; Kim, Hae-Ryoung; Yoon, Kyung Joong; Son, Ji-Won; Lee, Hae-Weon; Lee, Jong-Ho

2013-07-01

We applied screen-printed (La,Sr)CoO3 as a current-collecting layer of planar type unit-cell for lower temperature operation of SOFCs. In this study the effects of the cathode current-collecting layer on the performance of unit cell and symmetric half cell were investigated via AC and DC polarization experiments. According to our investigation, appropriately controlled current collecting layer was very effective to enhance the unit cell performance by reducing not only the ohmic resistance but also the polarization losses of SOFC cathode.

Dynamic Call Admission Control Scheme Based on Predictive User Mobility Behavior for Cellular Networks

NASA Astrophysics Data System (ADS)

Intarasothonchun, Silada; Thipchaksurat, Sakchai; Varakulsiripunth, Ruttikorn; Onozato, Yoshikuni

In this paper, we propose a modified scheme of MSODB and PMS, called Predictive User Mobility Behavior (PUMB) to improve performance of resource reservation and call admission control for cellular networks. This algorithm is proposed in which bandwidth is allocated more efficiently to neighboring cells by key mobility parameters in order to provide QoS guarantees for transferring traffic. The probability is used to form a cluster of cells and the shadow cluster, where a mobile unit is likely to visit. When a mobile unit may change the direction and migrate to the cell that does not belong to its shadow cluster, we can support it by making efficient use of predicted nonconforming call. Concomitantly, to ensure continuity of on-going calls with better utilization of resources, bandwidth is borrowed from predicted nonconforming calls and existing adaptive calls without affecting the minimum QoS guarantees. The performance of the PUMB is demonstrated by simulation results in terms of new call blocking probability, handoff call dropping probability, bandwidth utilization, call successful probability, and overhead message transmission when arrival rate and speed of mobile units are varied. Our results show that PUMB provides the better performances comparing with those of MSODB and PMS under different traffic conditions.

Measurement of UO2 surface oxidation using grazing-incidence x-ray diffraction: Implications for nuclear forensics

NASA Astrophysics Data System (ADS)

Tracy, Cameron L.; Chen, Chien-Hung; Park, Sulgiye; Davisson, M. Lee; Ewing, Rodney C.

2018-04-01

Nuclear forensics involves determination of the origin and history of interdicted nuclear materials based on the detection of signatures associated with their production and trafficking. The surface oxidation undergone by UO2 when exposed to air is a potential signature of its atmospheric exposure during handling and transport. To assess the sensitivity of this oxidation to atmospheric parameters, surface sensitive grazing-incidence x-ray diffraction (GIXRD) measurements were performed on UO2 samples exposed to air of varying relative humidity (34%, 56%, and 95% RH) and temperature (room temperature, 50 °C, and 100 °C). Near-surface unit cell contraction was observed following exposure, indicating oxidation of the surface and accompanying reduction of the uranium cation ionic radii. The extent of unit cell contraction provides a measure of the extent of oxidation, allowing for comparison of the effects of various exposure conditions. No clear influence of relative humidity on the extent of oxidation was observed, with samples exhibiting similar degrees of unit cell contraction at all relative humidities investigated. In contrast, the thickness of the oxidized layers increased substantially with increasing temperature, such that differences on the order of 10 °C yielded readily observable crystallographic signatures of the exposure conditions.

National Assessment of Oil and Gas Project: Areas of Historical Oil and Gas Exploration and Production in the United States

USGS Publications Warehouse

Biewick, Laura

2008-01-01

This report contains maps and associated spatial data showing historical oil and gas exploration and production in the United States. Because of the proprietary nature of many oil and gas well databases, the United States was divided into cells one-quarter square mile and the production status of all wells in a given cell was aggregated. Base-map reference data are included, using the U.S. Geological Survey (USGS) National Map, the USGS and American Geological Institute (AGI) Global GIS, and a World Shaded Relief map service from the ESRI Geography Network. A hardcopy map was created to synthesize recorded exploration data from 1859, when the first oil well was drilled in the U.S., to 2005. In addition to the hardcopy map product, the data have been refined and made more accessible through the use of Geographic Information System (GIS) tools. The cell data are included in a GIS database constructed for spatial analysis via the USGS Internet Map Service or by importing the data into GIS software such as ArcGIS. The USGS internet map service provides a number of useful and sophisticated geoprocessing and cartographic functions via an internet browser. Also included is a video clip of U.S. oil and gas exploration and production through time.

A New Compact Double-Negative Miniaturized Metamaterial for Wideband Operation.

PubMed

Hasan, Md Mehedi; Faruque, Mohammad Rashed Iqbal; Islam, Sikder Sunbeam; Islam, Mohammad Tariqul

2016-10-13

The aim of this paper is to introduce a compact double-negative (DNG) metamaterial that exhibits a negative refractive index (NRI) bandwidth of more than 3.6 GHz considering the frequency from 2 to 14 GHz. In this framework, two arms of the designed unit cell are split in a way that forms a Modified-Z-shape structure of the FR-4 substrate material. The finite integration technique (FIT)-based Computer Simulation Technology (CST) Microwave Studio is applied for computation, and the experimental setup for measuring the performance is performed inside two waveguide ports. Therefore, the measured data complies well with the simulated data of the unit cell at 0-degree and 90-degree rotation angles. The designed unit cell shows a negative refractive index from 3.482 to 7.096 GHz (bandwidth of 3.61 GHz), 7.876 to 10.047 GHz (bandwidth of 2.171 GHz), and 11.594 to 14 GHz (bandwidth of 2.406 GHz) in the microwave spectra. The design also exhibits almost the same wide negative refractive index bandwidth in the major region of the C-band and X-band if it is rotated 90 degrees. However, the novelty of the proposed structure lies in its effective medium ratio of more than 4, wide bandwidth, and compact size.

A novel VLSI processor architecture for supercomputing arrays

NASA Technical Reports Server (NTRS)

Venkateswaran, N.; Pattabiraman, S.; Devanathan, R.; Ahmed, Ashaf; Venkataraman, S.; Ganesh, N.

1993-01-01

Design of the processor element for general purpose massively parallel supercomputing arrays is highly complex and cost ineffective. To overcome this, the architecture and organization of the functional units of the processor element should be such as to suit the diverse computational structures and simplify mapping of complex communication structures of different classes of algorithms. This demands that the computation and communication structures of different class of algorithms be unified. While unifying the different communication structures is a difficult process, analysis of a wide class of algorithms reveals that their computation structures can be expressed in terms of basic IP,IP,OP,CM,R,SM, and MAA operations. The execution of these operations is unified on the PAcube macro-cell array. Based on this PAcube macro-cell array, we present a novel processor element called the GIPOP processor, which has dedicated functional units to perform the above operations. The architecture and organization of these functional units are such to satisfy the two important criteria mentioned above. The structure of the macro-cell and the unification process has led to a very regular and simpler design of the GIPOP processor. The production cost of the GIPOP processor is drastically reduced as it is designed on high performance mask programmable PAcube arrays.

A New Compact Double-Negative Miniaturized Metamaterial for Wideband Operation

PubMed Central

Hasan, Md. Mehedi; Faruque, Mohammad Rashed Iqbal; Islam, Sikder Sunbeam; Islam, Mohammad Tariqul

2016-01-01

The aim of this paper is to introduce a compact double-negative (DNG) metamaterial that exhibits a negative refractive index (NRI) bandwidth of more than 3.6 GHz considering the frequency from 2 to 14 GHz. In this framework, two arms of the designed unit cell are split in a way that forms a Modified-Z-shape structure of the FR-4 substrate material. The finite integration technique (FIT)-based Computer Simulation Technology (CST) Microwave Studio is applied for computation, and the experimental setup for measuring the performance is performed inside two waveguide ports. Therefore, the measured data complies well with the simulated data of the unit cell at 0-degree and 90-degree rotation angles. The designed unit cell shows a negative refractive index from 3.482 to 7.096 GHz (bandwidth of 3.61 GHz), 7.876 to 10.047 GHz (bandwidth of 2.171 GHz), and 11.594 to 14 GHz (bandwidth of 2.406 GHz) in the microwave spectra. The design also exhibits almost the same wide negative refractive index bandwidth in the major region of the C-band and X-band if it is rotated 90 degrees. However, the novelty of the proposed structure lies in its effective medium ratio of more than 4, wide bandwidth, and compact size. PMID:28773951

Non-volatile, high density, high speed, Micromagnet-Hall effect Random Access Memory (MHRAM)

NASA Technical Reports Server (NTRS)

Wu, Jiin C.; Katti, Romney R.; Stadler, Henry L.

1991-01-01

The micromagnetic Hall effect random access memory (MHRAM) has the potential of replacing ROMs, EPROMs, EEPROMs, and SRAMs because of its ability to achieve non-volatility, radiation hardness, high density, and fast access times, simultaneously. Information is stored magnetically in small magnetic elements (micromagnets), allowing unlimited data retention time, unlimited numbers of rewrite cycles, and inherent radiation hardness and SEU immunity, making the MHRAM suitable for ground based as well as spaceflight applications. The MHRAM device design is not affected by areal property fluctuations in the micromagnet, so high operating margins and high yield can be achieved in large scale integrated circuit (IC) fabrication. The MHRAM has short access times (less than 100 nsec). Write access time is short because on-chip transistors are used to gate current quickly, and magnetization reversal in the micromagnet can occur in a matter of a few nanoseconds. Read access time is short because the high electron mobility sensor (InAs or InSb) produces a large signal voltage in response to the fringing magnetic field from the micromagnet. High storage density is achieved since a unit cell consists only of two transistors and one micromagnet Hall effect element. By comparison, a DRAM unit cell has one transistor and one capacitor, and a SRAM unit cell has six transistors.

Establishment of a Human Blood-Brain Barrier Co-culture Model Mimicking the Neurovascular Unit Using Induced Pluri- and Multipotent Stem Cells.

PubMed

Appelt-Menzel, Antje; Cubukova, Alevtina; Günther, Katharina; Edenhofer, Frank; Piontek, Jörg; Krause, Gerd; Stüber, Tanja; Walles, Heike; Neuhaus, Winfried; Metzger, Marco

2017-04-11

In vitro models of the human blood-brain barrier (BBB) are highly desirable for drug development. This study aims to analyze a set of ten different BBB culture models based on primary cells, human induced pluripotent stem cells (hiPSCs), and multipotent fetal neural stem cells (fNSCs). We systematically investigated the impact of astrocytes, pericytes, and NSCs on hiPSC-derived BBB endothelial cell function and gene expression. The quadruple culture models, based on these four cell types, achieved BBB characteristics including transendothelial electrical resistance (TEER) up to 2,500 Ω cm 2 and distinct upregulation of typical BBB genes. A complex in vivo-like tight junction (TJ) network was detected by freeze-fracture and transmission electron microscopy. Treatment with claudin-specific TJ modulators caused TEER decrease, confirming the relevant role of claudin subtypes for paracellular tightness. Drug permeability tests with reference substances were performed and confirmed the suitability of the models for drug transport studies. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Cell Based Associations: A procedure for considering scarce and mixed mineral occurrences in predictive mapping

NASA Astrophysics Data System (ADS)

Tourlière, Bruno; Pakyuz-Charrier, Evren; Cassard, Daniel; Barbanson, Luc; Gumiaux, Charles

2015-05-01

Cell Based Association is an innovative mineral favorability procedure designed to answer special needs of the mining industry in data wise critical situations where usual favorability methods may not yield satisfactory results. Those situations relate to input data quality (e.g. clustered points, mixed and scarce data, approximate location) or some assumptions that are considered unreasonable (e.g. map areas relevance, conditional independence). The principle of CBA consists in replacing polygons of geological units with a square cell grid (hence the 'cell-based'). Each cell contains a range of units ('association') that are binary coded in terms of their presence (1) or absence (0) within study area. The loss of resolution inherent to this procedure is compensated by the enriched information contained in each cell owing to the notion of (lithological) association. Lithological associations are considered as binary spectra and as such are classified using Ascendant Hierarchical Clustering (AHC) thus obtaining a synthetic map of lithological associations. The prospectivity map shows as favourable the cells of the same AHC classes that the ones including mineral occurrences. It was observed that CBA can distinguish between different ore deposit varieties from a blended mineral occurrences data set. CBA can theoretically include any spatialized data (e.g. geophysics, structural data) as an extra variable to specify classification and narrow favourable areas. Doing so would make it an independent favorability mapping procedure and is still under development. Cell size in a grid is a critical parameter of the procedure; it must be compatible with the looked-for phenomena and should have a sufficient lithological variability. In addition to its use for producing favorability maps, a CBA-derived map could help in understanding the background information contained in geological maps. CBA can also be applied to other fields, such as agriculture and urban planning. Modelling of mineral prospectivity is a regional- or district scale mapping activity, whether field based or GIS based, which aims to delineate prospective areas for further exploration at the next higher scales of mapping. Notwithstanding the scale of mapping, mineral prospectivity is related to the degrees of presence and degrees of importance of individual pieces of spatial evidence of occurrence of mineral deposits of the type sought. That is, in a region or district under investigation, if there are more important pieces of spatial evidence in an area than in another area, then the former is considered to have higher prospectivity than the latter".

Analysis of Cellular DNA Content by Flow Cytometry.

PubMed

Darzynkiewicz, Zbigniew; Huang, Xuan; Zhao, Hong

2017-10-02

Cellular DNA content can be measured by flow cytometry with the aim of : (1) revealing cell distribution within the major phases of the cell cycle, (2) estimating frequency of apoptotic cells with fractional DNA content, and/or (3) disclosing DNA ploidy of the measured cell population. In this unit, simple and universally applicable methods for staining fixed cells are presented, as are methods that utilize detergents and/or proteolytic treatment to permeabilize cells and make DNA accessible to fluorochrome. Additionally, supravital cell staining with Hoechst 33342, which is primarily used for sorting live cells based on DNA-content differences for their subsequent culturing, is described. Also presented are methods for staining cell nuclei isolated from paraffin-embedded tissues. Available algorithms are listed for deconvolution of DNA-content-frequency histograms to estimate percentage of cells in major phases of the cell cycle and frequency of apoptotic cells with fractional DNA content. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley and Sons, Inc.

Analysis of Cellular DNA Content by Flow Cytometry.

PubMed

Darzynkiewicz, Zbigniew; Huang, Xuan; Zhao, Hong

2017-11-01

Cellular DNA content can be measured by flow cytometry with the aim of : (1) revealing cell distribution within the major phases of the cell cycle, (2) estimating frequency of apoptotic cells with fractional DNA content, and/or (3) disclosing DNA ploidy of the measured cell population. In this unit, simple and universally applicable methods for staining fixed cells are presented, as are methods that utilize detergents and/or proteolytic treatment to permeabilize cells and make DNA accessible to fluorochrome. Additionally, supravital cell staining with Hoechst 33342, which is primarily used for sorting live cells based on DNA-content differences for their subsequent culturing, is described. Also presented are methods for staining cell nuclei isolated from paraffin-embedded tissues. Available algorithms are listed for deconvolution of DNA-content-frequency histograms to estimate percentage of cells in major phases of the cell cycle and frequency of apoptotic cells with fractional DNA content. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley and Sons, Inc.

Negative extensibility metamaterials: phase diagram calculation

NASA Astrophysics Data System (ADS)

Klein, John T.; Karpov, Eduard G.

2017-12-01

Negative extensibility metamaterials are able to contract against the line of increasing external tension. A bistable unit cell exhibits several nonlinear mechanical behaviors including the negative extensibility response. Here, an exact form of the total mechanical potential is used based on engineering strain measure. The mechanical response is a function of the system parameters that specify unit cell dimensions and member stiffnesses. A phase diagram is calculated, which maps the response to regions in the diagram using the system parameters as the coordinate axes. Boundary lines pinpoint the onset of a particular mechanical response. Contour lines allow various material properties to be fine-tuned. Analogous to thermodynamic phase diagrams, there exist singular "triple points" which simultaneously satisfy conditions for three response types. The discussion ends with a brief statement about how thermodynamic phase diagrams differ from the phase diagram in this paper.

Bottom-up construction of a superstructure in a porous uranium-organic crystal

NASA Astrophysics Data System (ADS)

Li, Peng; Vermeulen, Nicolaas A.; Malliakas, Christos D.; Gómez-Gualdrón, Diego A.; Howarth, Ashlee J.; Mehdi, B. Layla; Dohnalkova, Alice; Browning, Nigel D.; O'Keeffe, Michael; Farha, Omar K.

2017-05-01

Bottom-up construction of highly intricate structures from simple building blocks remains one of the most difficult challenges in chemistry. We report a structurally complex, mesoporous uranium-based metal-organic framework (MOF) made from simple starting components. The structure comprises 10 uranium nodes and seven tricarboxylate ligands (both crystallographically nonequivalent), resulting in a 173.3-angstrom cubic unit cell enclosing 816 uranium nodes and 816 organic linkers—the largest unit cell found to date for any nonbiological material. The cuboctahedra organize into pentagonal and hexagonal prismatic secondary structures, which then form tetrahedral and diamond quaternary topologies with unprecedented complexity. This packing results in the formation of colossal icosidodecahedral and rectified hexakaidecahedral cavities with internal diameters of 5.0 nanometers and 6.2 nanometers, respectively—ultimately giving rise to the lowest-density MOF reported to date.

Effect of primary and secondary parameters on analytical estimation of effective thermal conductivity of two phase materials using unit cell approach

NASA Astrophysics Data System (ADS)

S, Chidambara Raja; P, Karthikeyan; Kumaraswamidhas, L. A.; M, Ramu

2018-05-01

Most of the thermal design systems involve two phase materials and analysis of such systems requires detailed understanding of the thermal characteristics of the two phase material. This article aimed to develop geometry dependent unit cell approach model by considering the effects of all primary parameters (conductivity ratio and concentration) and secondary parameters (geometry, contact resistance, natural convection, Knudsen and radiation) for the estimation of effective thermal conductivity of two-phase materials. The analytical equations have been formulated based on isotherm approach for 2-D and 3-D spatially periodic medium. The developed models are validated with standard models and suited for all kind of operating conditions. The results have shown substantial improvement compared to the existing models and are in good agreement with the experimental data.

Microwave metamaterials made by fused deposition 3D printing of a highly conductive copper-based filament

NASA Astrophysics Data System (ADS)

Xie, Yangbo; Ye, Shengrong; Reyes, Christopher; Sithikong, Pariya; Popa, Bogdan-Ioan; Wiley, Benjamin J.; Cummer, Steven A.

2017-05-01

This work reports a method for fabricating three-dimensional microwave metamaterials by fused deposition modeling 3D printing of a highly conductive polymer composite filament. The conductivity of such a filament is shown to be nearly equivalent to that of a perfect conductor for microwave metamaterial applications. The expanded degrees-of-freedom made available by 3D metamaterial designs are demonstrated by designing, fabricating, and testing a 3D-printed unit cell with a broadband permittivity as high as 14.4. The measured and simulated S-parameters agree well with a mean squared error smaller than 0.1. The presented method not only allows reliable and convenient fabrication of microwave metamaterials with high conductivity but also opens the door to exploiting the third dimension of the unit cell design space to achieve enhanced electromagnetic properties.

Flexible and elastic metamaterial absorber for low frequency, based on small-size unit cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoo, Y. J.; Zheng, H. Y.; Kim, Y. J.

2014-07-28

Using a planar and flexible metamaterial (MM), we obtained the low-frequency perfect absorption even with very small unit-cell size in snake-shape structure. These shrunken, deep-sub-wavelength and thin MM absorbers were numerically and experimentally investigated by increasing the inductance. The periodicity/thickness (the figure of merit for perfect absorption) is achieved to be 10 and 2 for single-snake-bar and 5-snake-bar structures, respectively. The ratio between periodicity and resonance wavelength (in mm) is close to 1/12 and 1/30 at 2 GHz and 400 MHz, respectively. The absorbers are specially designed for absorption peaks around 2 GHz and 400 MHz, which can be used for depressing the electromagneticmore » noise from everyday electronic devices and mobile phones.« less

Layer-by-layer growth by pulsed laser deposition in the unit-cell limit.

NASA Astrophysics Data System (ADS)

Kareev, M.; Prosandeev, S.; Liu, J.; Ryan, P.; Freeland, J. W.; Chakhalian, J.

2009-03-01

Unlike conventional growth of complex oxide heterostructures, the ultimate unit cell limit imposes strict constrains for a multitude of parameters critical to layer-by-layer growth. Here we report on detailed analysis of far-from-equilibrium growth by interrupted pulsed laser deposition with application to RENiO3/LaAlO3 superlattices grown on a diverse set of substrates SrTiO3, NdGaO3, LSAT and LaAlO3. A combination of in-situ high-pressure RHEED and AFM along with extensive data obtained from synchrotron based XRD and resonant XAS allows us critically assess the meaning of RHEED intensity oscillation and the effect of a polar/non-polar interface on the heteroepitaxial growth. The role of defects formed during the initial stages of growth is also addressed.

Excluding Anti-cytomegalovirus Immunoglobulin M-Positive Cord Blood Units Has a Minimal Impact on the Korean Public Cord Blood Bank Inventory

PubMed Central

Shin, Sue; Roh, Eun Youn; Oh, Sohee; Song, Eun Young; Kim, Eui Chong; Yoon, Jong Hyun

2017-01-01

Cord blood units (CBUs) for transplantation should be free of communicable disease and must contain a specific amount of total nucleated cells and CD34+ cells. Although posttransplantation cytomegalovirus (CMV) infections are from latent infection in patients, ensuring CMV-free CBUs by performing CMV-specific IgM and nucleic acid amplification testing (NAT) is one of the mandatory procedures for the safety of CBUs. However, the exclusion policies (based on these test results) vary among nations and institutions. We tested 28,000 processed CBUs between May 2006 and June 2014. The cord blood leukocytes from CMV IgM-positive samples were then subjected to NAT. The total nucleated cell and CD34+ cell counts were measured for each CBU, and the results were compared to the CMV IgM and IgG results. The seroprevalence of CMV among pregnant women was 98.1% (18,459/18,818) for IgG and 1.7% (441/25,293) for IgM. The concentration and the total number of CD34+ cells were significantly higher in CBUs from IgM-negative mothers compared to those from IgM-positive mothers (72.4/μl vs. 57.2/μl, respectively, p < 0.0001; 1.45 × 106/unit vs. 1.15 × 106/unit, respectively, p < 0.0001). Among CBUs with positive CMV IgM in their mothers' plasma or cord blood plasma, only 0.58% of the samples (3/517) had a positive NAT. The number of excluded CBUs from inventory due to positive CMV IgM in the cord blood was 54 of 18,326 (0.3%). For inventory purposes, it is appropriate to remove CBUs with positive cord blood CMV IgM findings irrespective of the NAT status as well as positive maternal CMV IgM in South Korea. PMID:27524276

Excluding Anti-cytomegalovirus Immunoglobulin M-Positive Cord Blood Units Has a Minimal Impact on the Korean Public Cord Blood Bank Inventory.

PubMed

Shin, Sue; Roh, Eun Youn; Oh, Sohee; Song, Eun Young; Kim, Eui Chong; Yoon, Jong Hyun

2017-01-24

Cord blood units (CBUs) for transplantation should be free of communicable disease and must contain a specific amount of total nucleated cells and CD34+ cells. Although posttransplantation cytomegalovirus (CMV) infections are from latent infection in patients, ensuring CMV-free CBUs by performing CMV-specific IgM and nucleic acid amplification testing (NAT) is one of the mandatory procedures for the safety of CBUs. However, the exclusion policies (based on these test results) vary among nations and institutions. We tested 28,000 processed CBUs between May 2006 and June 2014. The cord blood leukocytes from CMV IgM-positive samples were then subjected to NAT. The total nucleated cell and CD34+ cell counts were measured for each CBU, and the results were compared to the CMV IgM and IgG results. The seroprevalence of CMV among pregnant women was 98.1% (18,459/18,818) for IgG and 1.7% (441/25,293) for IgM. The concentration and the total number of CD34+ cells were significantly higher in CBUs from IgM-negative mothers compared to those from IgM-positive mothers (72.4/μl vs. 57.2/μl, respectively, p < 0.0001; 1.45 × 106/unit vs. 1.15 × 106/unit, respectively, p < 0.0001). Among CBUs with positive CMV IgM in their mothers' plasma or cord blood plasma, only 0.58% of the samples (3/517) had a positive NAT. The number of excluded CBUs from inventory due to positive CMV IgM in the cord blood was 54 of 18,326 (0.3%). For inventory purposes, it is appropriate to remove CBUs with positive cord blood CMV IgM findings irrespective of the NAT status as well as positive maternal CMV IgM in South Korea.

Octasaccharide is the minimal length unit required for efficient binding of cyclophilin B to heparin and cell surface heparan sulphate.

PubMed

Vanpouille, Christophe; Denys, Agnès; Carpentier, Mathieu; Pakula, Rachel; Mazurier, Joël; Allain, Fabrice

2004-09-01

Cyclophilin B (CyPB) is a heparin-binding protein first identified as a receptor for cyclosporin A. In previous studies, we reported that CyPB triggers chemotaxis and integrin-mediated adhesion of T-lymphocytes by way of interaction with two types of binding sites. The first site corresponds to a signalling receptor; the second site has been identified as heparan sulphate (HS) and appears crucial to induce cell adhesion. Characterization of the HS-binding unit is critical to understand the requirement of HS in pro-adhesive activity of CyPB. By using a strategy based on gel mobility shift assays with fluorophore-labelled oligosaccharides, we demonstrated that the minimal heparin unit required for efficient binding of CyPB is an octasaccharide. The mutants CyPB(KKK-) [where KKK- refers to the substitutions K3A(Lys3-->Ala)/K4A/K5A] and CyPB(DeltaYFD) (where Tyr14-Phe-Asp16 has been deleted) failed to interact with octasaccharides, confirming that the Y14FD16 and K3KK5 clusters are required for CyPB binding. Molecular modelling revealed that both clusters are spatially arranged so that they may act synergistically to form a binding site for the octasaccharide. We then demonstrated that heparin-derived octasaccharides and higher degree of polymerization oligosaccharides inhibited the interaction between CyPB and fluorophore-labelled HS chains purified from T-lymphocytes, and strongly reduced the HS-dependent pro-adhesive activity of CyPB. However, oligosaccharides or heparin were unable to restore adhesion of heparinase-treated T-lymphocytes, indicating that HS has to be present on the cell membrane to support the pro-adhesive activity of CyPB. Altogether, these results demonstrate that the octasaccharide is likely to be the minimal length unit required for efficient binding of CyPB to cell surface HS and consequent HS-dependent cell responses.

Octasaccharide is the minimal length unit required for efficient binding of cyclophilin B to heparin and cell surface heparan sulphate

PubMed Central

2004-01-01

Cyclophilin B (CyPB) is a heparin-binding protein first identified as a receptor for cyclosporin A. In previous studies, we reported that CyPB triggers chemotaxis and integrin-mediated adhesion of T-lymphocytes by way of interaction with two types of binding sites. The first site corresponds to a signalling receptor; the second site has been identified as heparan sulphate (HS) and appears crucial to induce cell adhesion. Characterization of the HS-binding unit is critical to understand the requirement of HS in pro-adhesive activity of CyPB. By using a strategy based on gel mobility shift assays with fluorophore-labelled oligosaccharides, we demonstrated that the minimal heparin unit required for efficient binding of CyPB is an octasaccharide. The mutants CyPBKKK− [where KKK− refers to the substitutions K3A(Lys3→Ala)/K4A/K5A] and CyPBΔYFD (where Tyr14-Phe-Asp16 has been deleted) failed to interact with octasaccharides, confirming that the Y14FD16 and K3KK5 clusters are required for CyPB binding. Molecular modelling revealed that both clusters are spatially arranged so that they may act synergistically to form a binding site for the octasaccharide. We then demonstrated that heparin-derived octasaccharides and higher degree of polymerization oligosaccharides inhibited the interaction between CyPB and fluorophore-labelled HS chains purified from T-lymphocytes, and strongly reduced the HS-dependent pro-adhesive activity of CyPB. However, oligosaccharides or heparin were unable to restore adhesion of heparinase-treated T-lymphocytes, indicating that HS has to be present on the cell membrane to support the pro-adhesive activity of CyPB. Altogether, these results demonstrate that the octasaccharide is likely to be the minimal length unit required for efficient binding of CyPB to cell surface HS and consequent HS-dependent cell responses. PMID:15109301

Efficient priming of CD4 T cells by Langerin-expressing dendritic cells targeted with porcine epidemic diarrhea virus spike protein domains in pigs.

PubMed

Subramaniam, Sakthivel; Cao, Dianjun; Tian, Debin; Cao, Qian M; Overend, Christopher; Yugo, Danielle M; Matzinger, Shannon R; Rogers, Adam J; Heffron, C Lynn; Catanzaro, Nicholas; Kenney, Scott P; Opriessnig, Tanja; Huang, Yao-Wei; Labarque, Geoffrey; Wu, Stephen Q; Meng, Xiang-Jin

2017-01-02

Porcine epidemic diarrhea virus (PEDV) first emerged in the United States in 2013 causing high mortality and morbidity in neonatal piglets with immense economic losses to the swine industry. PEDV is an alpha-coronavirus replicating primarily in porcine intestinal cells. PEDV vaccines are available in Asia and Europe, and conditionally-licensed vaccines recently became available in the United States but the efficacies of these vaccines in eliminating PEDV from swine populations are questionable. In this study, the immunogenicity of a subunit vaccine based on the spike protein of PEDV, which was directly targeted to porcine dendritic cells (DCs) expressing Langerin, was assessed. The PEDV S antigen was delivered to the dendritic cells through a single-chain antibody specific to Langerin and the targeted cells were stimulated with cholera toxin adjuvant. This approach, known as "dendritic cell targeting," greatly improved PEDV S antigen-specific T cell interferon-γ responses in the CD4 pos CD8 pos T cell compartment in pigs as early as 7days upon transdermal administration. When the vaccine protein was targeted to Langerin pos DCs systemically through intramuscular vaccination, it induced higher serum IgG and IgA responses in pigs, though these responses require a booster dose, and the magnitude of T cell responses were lower as compared to transdermal vaccination. We conclude that PEDV spike protein domains targeting Langerin-expressing dendritic cells significantly increased CD4 T cell immune responses in pigs. The results indicate that the immunogenicity of protein subunit vaccines can be greatly enhanced by direct targeting of the vaccine antigens to desirable dendritic cell subsets in pigs. Copyright © 2016 Elsevier B.V. All rights reserved.

Photovoltaic Powering And Control System For Electrochromic Windows

DOEpatents

Schulz, Stephen C.; Michalski, Lech A.; Volltrauer, Hermann N.; Van Dine, John E.

2000-04-25

A sealed insulated glass unit is provided with an electrochromic device for modulating light passing through the unit. The electrochromic device is controlled from outside the unit by a remote control electrically unconnected to the device. Circuitry within the unit may be magnetically controlled from outside. The electrochromic device is powered by a photovoltaic cells. The photovoltaic cells may be positioned so that at least a part of the light incident on the cell passes through the electrochromic device, providing a form of feedback control. A variable resistance placed in parallel with the electrochromic element is used to control the response of the electrochromic element to changes in output of the photovoltaic cell.

Additively Manufactured Open-Cell Porous Biomaterials Made from Six Different Space-Filling Unit Cells: The Mechanical and Morphological Properties

PubMed Central

Ahmadi, Seyed Mohammad; Amin Yavari, Saber; Wauthle, Ruebn; Pouran, Behdad; Schrooten, Jan; Weinans, Harrie; Zadpoor, Amir A.

2015-01-01

It is known that the mechanical properties of bone-mimicking porous biomaterials are a function of the morphological properties of the porous structure, including the configuration and size of the repeating unit cell from which they are made. However, the literature on this topic is limited, primarily because of the challenge in fabricating porous biomaterials with arbitrarily complex morphological designs. In the present work, we studied the relationship between relative density (RD) of porous Ti6Al4V EFI alloy and five compressive properties of the material, namely elastic gradient or modulus (Es20–70), first maximum stress, plateau stress, yield stress, and energy absorption. Porous structures with different RD and six different unit cell configurations (cubic (C), diamond (D), truncated cube (TC), truncated cuboctahedron (TCO), rhombic dodecahedron (RD), and rhombicuboctahedron (RCO)) were fabricated using selective laser melting. Each of the compressive properties increased with increase in RD, the relationship being of a power law type. Clear trends were seen in the influence of unit cell configuration and porosity on each of the compressive properties. For example, in terms of Es20–70, the structures may be divided into two groups: those that are stiff (comprising those made using C, TC, TCO, and RCO unit cell) and those that are compliant (comprising those made using D and RD unit cell). PMID:28788037

Additively Manufactured Open-Cell Porous Biomaterials Made from Six Different Space-Filling Unit Cells: The Mechanical and Morphological Properties.

PubMed

Ahmadi, Seyed Mohammad; Yavari, Saber Amin; Wauthle, Ruebn; Pouran, Behdad; Schrooten, Jan; Weinans, Harrie; Zadpoor, Amir A

2015-04-21

It is known that the mechanical properties of bone-mimicking porous biomaterials are a function of the morphological properties of the porous structure, including the configuration and size of the repeating unit cell from which they are made. However, the literature on this topic is limited, primarily because of the challenge in fabricating porous biomaterials with arbitrarily complex morphological designs. In the present work, we studied the relationship between relative density (RD) of porous Ti6Al4V EFI alloy and five compressive properties of the material, namely elastic gradient or modulus (E s20 -70 ), first maximum stress, plateau stress, yield stress, and energy absorption. Porous structures with different RD and six different unit cell configurations (cubic (C), diamond (D), truncated cube (TC), truncated cuboctahedron (TCO), rhombic dodecahedron (RD), and rhombicuboctahedron (RCO)) were fabricated using selective laser melting. Each of the compressive properties increased with increase in RD, the relationship being of a power law type. Clear trends were seen in the influence of unit cell configuration and porosity on each of the compressive properties. For example, in terms of E s20 -70 , the structures may be divided into two groups: those that are stiff (comprising those made using C, TC, TCO, and RCO unit cell) and those that are compliant (comprising those made using D and RD unit cell).

CRISPR-Cas9-Based Genome Editing of Human Induced Pluripotent Stem Cells.

PubMed

Giacalone, Joseph C; Sharma, Tasneem P; Burnight, Erin R; Fingert, John F; Mullins, Robert F; Stone, Edwin M; Tucker, Budd A

2018-02-28

Human induced pluripotent stem cells (hiPSCs) are the ideal cell source for autologous cell replacement. However, for patients with Mendelian diseases, genetic correction of the original disease-causing mutation is likely required prior to cellular differentiation and transplantation. The emergence of the CRISPR-Cas9 system has revolutionized the field of genome editing. By introducing inexpensive reagents that are relatively straightforward to design and validate, it is now possible to correct genetic variants or insert desired sequences at any location within the genome. CRISPR-based genome editing of patient-specific iPSCs shows great promise for future autologous cell replacement therapies. One caveat, however, is that hiPSCs are notoriously difficult to transfect, and optimized experimental design considerations are often necessary. This unit describes design strategies and methods for efficient CRISPR-based genome editing of patient- specific iPSCs. Additionally, it details a flexible approach that utilizes positive selection to generate clones with a desired genomic modification, Cre-lox recombination to remove the integrated selection cassette, and negative selection to eliminate residual hiPSCs with intact selection cassettes. © 2018 by John Wiley & Sons, Inc. Copyright © 2018 John Wiley & Sons, Inc.

Synthetic biology for pharmaceutical drug discovery

PubMed Central

Trosset, Jean-Yves; Carbonell, Pablo

2015-01-01

Synthetic biology (SB) is an emerging discipline, which is slowly reorienting the field of drug discovery. For thousands of years, living organisms such as plants were the major source of human medicines. The difficulty in resynthesizing natural products, however, often turned pharmaceutical industries away from this rich source for human medicine. More recently, progress on transformation through genetic manipulation of biosynthetic units in microorganisms has opened the possibility of in-depth exploration of the large chemical space of natural products derivatives. Success of SB in drug synthesis culminated with the bioproduction of artemisinin by microorganisms, a tour de force in protein and metabolic engineering. Today, synthetic cells are not only used as biofactories but also used as cell-based screening platforms for both target-based and phenotypic-based approaches. Engineered genetic circuits in synthetic cells are also used to decipher disease mechanisms or drug mechanism of actions and to study cell–cell communication within bacteria consortia. This review presents latest developments of SB in the field of drug discovery, including some challenging issues such as drug resistance and drug toxicity. PMID:26673570

Microfluidic-based mini-metagenomics enables discovery of novel microbial lineages from complex environmental samples

PubMed Central

Yu, Feiqiao Brian; Blainey, Paul C; Schulz, Frederik; Woyke, Tanja; Horowitz, Mark A; Quake, Stephen R

2017-01-01

Metagenomics and single-cell genomics have enabled genome discovery from unknown branches of life. However, extracting novel genomes from complex mixtures of metagenomic data can still be challenging and represents an ill-posed problem which is generally approached with ad hoc methods. Here we present a microfluidic-based mini-metagenomic method which offers a statistically rigorous approach to extract novel microbial genomes while preserving single-cell resolution. We used this approach to analyze two hot spring samples from Yellowstone National Park and extracted 29 new genomes, including three deeply branching lineages. The single-cell resolution enabled accurate quantification of genome function and abundance, down to 1% in relative abundance. Our analyses of genome level SNP distributions also revealed low to moderate environmental selection. The scale, resolution, and statistical power of microfluidic-based mini-metagenomics make it a powerful tool to dissect the genomic structure of microbial communities while effectively preserving the fundamental unit of biology, the single cell. DOI: http://dx.doi.org/10.7554/eLife.26580.001 PMID:28678007

Architecture of Eph receptor clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Himanen, Juha P.; Yermekbayeva, Laila; Janes, Peter W.

2010-10-04

Eph receptor tyrosine kinases and their ephrin ligands regulate cell navigation during normal and oncogenic development. Signaling of Ephs is initiated in a multistep process leading to the assembly of higher-order signaling clusters that set off bidirectional signaling in interacting cells. However, the structural and mechanistic details of this assembly remained undefined. Here we present high-resolution structures of the complete EphA2 ectodomain and complexes with ephrin-A1 and A5 as the base unit of an Eph cluster. The structures reveal an elongated architecture with novel Eph/Eph interactions, both within and outside of the Eph ligand-binding domain, that suggest the molecular mechanismmore » underlying Eph/ephrin clustering. Structure-function analysis, by using site-directed mutagenesis and cell-based signaling assays, confirms the importance of the identified oligomerization interfaces for Eph clustering.« less

Transient analysis of a thermal storage unit involving a phase change material

NASA Technical Reports Server (NTRS)

Griggs, E. I.; Pitts, D. R.; Humphries, W. R.

1974-01-01

The transient response of a single cell of a typical phase change material type thermal capacitor has been modeled using numerical conductive heat transfer techniques. The cell consists of a base plate, an insulated top, and two vertical walls (fins) forming a two-dimensional cavity filled with a phase change material. Both explicit and implicit numerical formulations are outlined. A mixed explicit-implicit scheme which treats the fin implicity while treating the phase change material explicitly is discussed. A band algorithmic scheme is used to reduce computer storage requirements for the implicit approach while retaining a relatively fine grid. All formulations are presented in dimensionless form thereby enabling application to geometrically similar problems. Typical parametric results are graphically presented for the case of melting with constant heat input to the base of the cell.

Trends in noncompliance with milk quality standards for Dairy Herd Improvement herds in the United States

USDA-ARS?s Scientific Manuscript database

Frequency of herd noncompliance for somatic cell count (SCC) based on current US and European Union (EU) standards as well as for standards proposed by the National Milk Producers Federation (NMPF) was examined for US Dairy Herd Improvement (DHI) herds. For current US standards, regulatory action is...

40 CFR 63.7522 - Can I use emissions averaging to comply with this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

.... (vi) Dutch ovens/pile burners designed to burn biomass/bio-based solid. (vii) Fuel Cells designed to...: Industrial, Commercial, and Institutional Boilers and Process Heaters Testing, Fuel Analyses, and Initial... allowed as follows: (i) You may average among units in any of the solid fuel subcategories. (ii) You may...

Hydrogen Production Cost Analysis | Hydrogen and Fuel Cells | NREL

Science.gov Websites

Analysis Hydrogen Production Cost Analysis This interactive map displays the results of a 2011 NREL analysis on the cost of hydrogen from electrolysis at potential sites across the United States. NREL analyzed the cost of hydrogen production via wind-based water electrolysis at 42 potential sites in 11

Toxic Hazards Research Unit Annual Report: 1987

DTIC Science & Technology

1988-03-01

Low Density Lipoproteins and in Model Membranes 14 Sep Is Cigarette Smoking Neurotoric? Mr. Steven Goden Dr. R. Kutzman 4> ’October 1986 through September 1987 2I ...based pharmcokinetic model phosphoniteo,o-diethylmethyl quantitative structure activity relationship respiratory epithelium Salmonella sensitization j...in Cultured Respiratory Epithelial Cells ----------------------- ------------ 73 6 PHARMACOKINETIC AND PHARMACODYNAMIC MODELING .------------------ 78

Human lacrimal gland regeneration: Perspectives and review of literature

PubMed Central

Tiwari, Shubha; Ali, Mohammad Javed; Vemuganti, Geeta K.

2013-01-01

The human lacrimal gland is an essential component of the lacrimal functional unit (LFU). Any perturbation of this unit can lead to the debilitating morbid condition called the dry eye syndrome (DES). The current line of therapy available for dry eye remains supportive and palliative with the patient being dependent on life long and frequent administration of lubricating eye drops. Even advanced therapies like punctual plugs, cyclosporine B administration, and salivary gland auto-transplantation have led to a limited success. Under these scenarios, the option of cell based therapy needs to be explored to provide better and long term relief to these patients. This review gives an overview of the efforts in lacrimal gland regeneration and examines the past and ongoing research in cell based therapies in animals as well as human lacrimal gland cultures. The authors discuss their first of its kind functionally viable human lacrimal gland in vitro culture system from fresh exenteration specimens. A brief overview of research in near future and the potential implications of lacrimal gland regenerative therapies have been discussed. PMID:24526853

Human lacrimal gland regeneration: Perspectives and review of literature.

PubMed

Tiwari, Shubha; Ali, Mohammad Javed; Vemuganti, Geeta K

2014-01-01

The human lacrimal gland is an essential component of the lacrimal functional unit (LFU). Any perturbation of this unit can lead to the debilitating morbid condition called the dry eye syndrome (DES). The current line of therapy available for dry eye remains supportive and palliative with the patient being dependent on life long and frequent administration of lubricating eye drops. Even advanced therapies like punctual plugs, cyclosporine B administration, and salivary gland auto-transplantation have led to a limited success. Under these scenarios, the option of cell based therapy needs to be explored to provide better and long term relief to these patients. This review gives an overview of the efforts in lacrimal gland regeneration and examines the past and ongoing research in cell based therapies in animals as well as human lacrimal gland cultures. The authors discuss their first of its kind functionally viable human lacrimal gland in vitro culture system from fresh exenteration specimens. A brief overview of research in near future and the potential implications of lacrimal gland regenerative therapies have been discussed.

Intracistronic complementation in the simian virus 40 A gene.

PubMed Central

Tornow, J; Cole, C N

1983-01-01

A set of eight simian virus 40 mutants was constructed with lesions in the A gene, which encodes the large tumor (T) antigen. These mutants have small deletions (3-20 base pairs) at either 0.497, 0.288, or 0.243 map units. Mutants having both in-phase and frameshift mutations at each site were isolated. Neither plaque formation nor replication of the mutant DNAs could be detected after transfection of monkey kidney cells. Another nonviable mutant, dlA2459, had a 14-base-pair deletion at 0.193 map unit and was positive for viral DNA replication. Each of the eight mutants were tested for ability to form plaques after cotransfection with dlA2459 DNA. The four mutants that had in-phase deletions were able to complement dlA2459. The other four, which had frameshift deletions, did not. No plaques were formed after cotransfection of cells with any other pair of group A mutants. This suggests that the defect in dlA2459 defines a distinct functional domain of simian virus 40 T antigen. Images PMID:6312452

The spatial distribution of two dimensional electron gas at the LaTiO3/KTaO3 interface

NASA Astrophysics Data System (ADS)

Song, Qi; Peng, Rui; Xu, Haichao; Feng, Donglai

2017-08-01

We report the photoemission spectroscopy studies on the newly discovered two dimensional electron gas (2DEG) system LaTiO3/KTaO3, whose interfacial carriers show much higher mobility than that in LaAlO3/SrTiO3 at room temperature, thus raising the application prospect of transition metal oxide-based 2DEG. By measuring the density of states at the Fermi energy (EF), we directly reveal the spatial distribution of the conducting electrons at the interface. The density of states near EF of the topmost LTO reaches the highest when LTO is 2-unit-cell thick, and diminishes at the 5th unit cell of LTO. We discussed the origin of such a spacial distribution of conducting electrons and its relation with 2DEG, and proposed two possible scenarios based on electrostatic relaxations and chemical reconstructions. These results offer experimental clues in understanding the characteristics and origin of the 2DEG, and also shed light on improving the performance of 2DEG.

The spatial distribution of two dimensional electron gas at the LaTiO3/KTaO3 interface.

PubMed

Song, Qi; Peng, Rui; Xu, Haichao; Feng, Donglai

2017-08-09

We report the photoemission spectroscopy studies on the newly discovered two dimensional electron gas (2DEG) system LaTiO 3 /KTaO 3 , whose interfacial carriers show much higher mobility than that in LaAlO 3 /SrTiO 3 at room temperature, thus raising the application prospect of transition metal oxide-based 2DEG. By measuring the density of states at the Fermi energy (E F ), we directly reveal the spatial distribution of the conducting electrons at the interface. The density of states near E F of the topmost LTO reaches the highest when LTO is 2-unit-cell thick, and diminishes at the 5th unit cell of LTO. We discussed the origin of such a spacial distribution of conducting electrons and its relation with 2DEG, and proposed two possible scenarios based on electrostatic relaxations and chemical reconstructions. These results offer experimental clues in understanding the characteristics and origin of the 2DEG, and also shed light on improving the performance of 2DEG.

High-crystalline medium-band-gap polymers consisting of benzodithiophene and benzotriazole derivatives for organic photovoltaic cells.

PubMed

Kim, Ji-Hoon; Song, Chang Eun; Shin, Nara; Kang, Hyunbum; Wood, Sebastian; Kang, In-Nam; Kim, Bumjoon J; Kim, Bongsoo; Kim, Ji-Seon; Shin, Won Suk; Hwang, Do-Hoon

2013-12-26

Two semiconducting conjugated polymers were synthesized via Stille polymerization. The structures combined unsubstituted or (triisopropylsilyl)ethynyl (TIPS)-substituted 2,6-bis(trimethylstannyl)benzo[1,2-b:4.5-b']dithiophene (BDT) as a donor unit and benzotriazole with a symmetrically branched alkyl side chain (DTBTz) as an acceptor unit. We investigated the effects of the different BDT moieties on the optical, electrochemical, and photovoltaic properties of the polymers and the film crystallinities and carrier mobilities. The optical-band-gap energies were measured to be 1.97 and 1.95 eV for PBDT-DTBTz and PTIPSBDT-DTBTz, respectively. Bulk heterojunction photovoltaic devices were fabricated and power conversion efficiencies of 5.5% and 2.9% were found for the PTIPSBDT-DTBTz- and PBDT-DTBTz-based devices, respectively. This difference was explained by the more optimal morphology and higher carrier mobility in the PTIPSBDT-DTBTz-based devices. This work demonstrates that, under the appropriate processing conditions, TIPS groups can change the molecular ordering and lower the highest occupied molecular orbital level, providing the potential for improved solar cell performance.

Stem Cells for Osteochondral Regeneration.

PubMed

Canadas, Raphaël F; Pirraco, Rogério P; Oliveira, J Miguel; Reis, Rui L; Marques, Alexandra P

2018-01-01

Stem cell research plays a central role in the future of medicine, which is mainly dependent on the advances on regenerative medicine (RM), specifically in the disciplines of tissue engineering (TE) and cellular therapeutics. All RM strategies depend upon the harnessing, stimulation, or guidance of endogenous developmental or repair processes in which cells have an important role. Among the most clinically challenging disorders, cartilage degeneration, which also affects subchondral bone becoming an osteochondral (OC) defect, is one of the most demanding. Although primary cells have been clinically applied, stem cells are currently seen as the promising tool of RM-related research because of its availability, in vitro proliferation ability, pluri- or multipotency, and immunosuppressive features. Being the OC unit, a transition from the bone to cartilage, mesenchymal stem cells (MSCs) are the main focus for OC regeneration. Promising alternatives, which can also be obtained from the patient or at banks and have great differentiation potential toward a wide range of specific cell types, have been reported. Still, ethical concerns and tumorigenic risk are currently under discussion and assessment. In this book chapter, we revise the existing stem cell-based approaches for engineering bone and cartilage, focusing on cell therapy and TE. Furthermore, 3D OC composites based on cell co-cultures are described. Finally, future directions and challenges still to be faced are critically discussed.

Micromechanics Fatigue Damage Analysis Modeling for Fabric Reinforced Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Min, J. B.; Xue, D.; Shi, Y.

2013-01-01

A micromechanics analysis modeling method was developed to analyze the damage progression and fatigue failure of fabric reinforced composite structures, especially for the brittle ceramic matrix material composites. A repeating unit cell concept of fabric reinforced composites was used to represent the global composite structure. The thermal and mechanical properties of the repeating unit cell were considered as the same as those of the global composite structure. The three-phase micromechanics, the shear-lag, and the continuum fracture mechanics models were integrated with a statistical model in the repeating unit cell to predict the progressive damages and fatigue life of the composite structures. The global structure failure was defined as the loss of loading capability of the repeating unit cell, which depends on the stiffness reduction due to material slice failures and nonlinear material properties in the repeating unit cell. The present methodology is demonstrated with the analysis results evaluated through the experimental test performed with carbon fiber reinforced silicon carbide matrix plain weave composite specimens.

Nanosecond monolithic CMOS readout cell

DOEpatents

Souchkov, Vitali V.

2004-08-24

A pulse shaper is implemented in monolithic CMOS with a delay unit formed of a unity gain buffer. The shaper is formed of a difference amplifier having one input connected directly to an input signal and a second input connected to a delayed input signal through the buffer. An elementary cell is based on the pulse shaper and a timing circuit which gates the output of an integrator connected to the pulse shaper output. A detector readout system is formed of a plurality of elementary cells, each connected to a pixel of a pixel array, or to a microstrip of a plurality of microstrips, or to a detector segment.

Extraction of Carbon Dioxide and Hydrogen from Seawater by an Electrochemical Acidification Cell. Part 4. Electrode Compartments of Cell Modified and Tested in Scaled-Up Mobile Unit

DTIC Science & Technology

2013-09-03

Electrochemical Acidification Cell Part IV: Electrode Compartments of Cell Modified and Tested in Scaled-Up Mobile Unit September 3, 2013 Approved for public...OF ABSTRACT Extraction of Carbon Dioxide and Hydrogen from Seawater by an Electrochemical Acidification Cell Part IV: Electrode Compartments of Cell...Electrochemical acidification cell Carbon dioxide Hydrogen Polarity reversal An electrochemical acidification cell was scaled-up and integrated into a

Photoanode Thickness Optimization and Impedance Spectroscopic Analysis of Dye-Sensitized Solar Cells based on a Carbazole-Containing Ruthenium Dye

NASA Astrophysics Data System (ADS)

Choi, Jongwan; Kim, Felix Sunjoo

2018-03-01

We studied the influence of photoanode thickness on the photovoltaic characteristics and impedance responses of the dye-sensitized solar cells based on a ruthenium dye containing a hexyloxyl-substituted carbazole unit (Ru-HCz). As the thickness of photoanode increases from 4.2 μm to 14.8 μm, the dye-loading amount and the efficiency increase. The device with thicker photoanode shows a decrease in the efficiency due to the higher probability of recombination of electron-hole pairs before charge extraction. We also analyzed the electron-transfer and recombination characteristics as a function of photoanode thickness through detailed electrochemical impedance spectroscopy analysis.

21 CFR 640.15 - Segments for testing.

Code of Federal Regulations, 2014 CFR

2014-04-01

... cells. (c) All segments accompanying a unit of Red Blood Cells shall be filled at the time the blood is... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.15 Segments for testing... provided with each unit of Whole Blood or Red Blood Cells when issued or reissued. (b) Before they are...

21 CFR 640.15 - Segments for testing.

Code of Federal Regulations, 2011 CFR

2011-04-01

... cells. (c) All segments accompanying a unit of Red Blood Cells shall be filled at the time the blood is... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.15 Segments for testing... provided with each unit of Whole Blood or Red Blood Cells when issued or reissued. (b) Before they are...

21 CFR 640.15 - Segments for testing.

Code of Federal Regulations, 2013 CFR

2013-04-01

... cells. (c) All segments accompanying a unit of Red Blood Cells shall be filled at the time the blood is... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.15 Segments for testing... provided with each unit of Whole Blood or Red Blood Cells when issued or reissued. (b) Before they are...

21 CFR 640.15 - Segments for testing.

Code of Federal Regulations, 2012 CFR

2012-04-01

... cells. (c) All segments accompanying a unit of Red Blood Cells shall be filled at the time the blood is... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.15 Segments for testing... provided with each unit of Whole Blood or Red Blood Cells when issued or reissued. (b) Before they are...

21 CFR 640.15 - Segments for testing.

Code of Federal Regulations, 2010 CFR

2010-04-01

... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.15 Segments for testing... provided with each unit of Whole Blood or Red Blood Cells when issued or reissued. (b) Before they are... cells. (c) All segments accompanying a unit of Red Blood Cells shall be filled at the time the blood is...

Telomere content measurement in human hematopoietic cells: Comparative analysis of qPCR and Flow-FISH techniques.

PubMed

Wand, Taylor; Fang, Mike; Chen, Christina; Hardy, Nathan; McCoy, J Philip; Dumitriu, Bogdan; Young, Neal S; Biancotto, Angélique

2016-10-01

Abnormal telomere lengths have been linked to cancer and other hematologic disorders. Determination of mean telomere content (MTC) is traditionally performed by Southern blotting and densitometry, giving a mean telomere restriction fragment (TRF) value for the total cell population studied. Here, we compared a quantitative Polymerase Chain Reaction approach (qPCR) and a flow cytometric approach, fluorescence in situ hybridization (Flow-FISH), to evaluate telomere content distribution in total patient peripheral blood mononuclear cells or specific cell populations. Flow-FISH is based on in situ hybridization using a fluorescein-labeled peptide nucleic acid (PNA) (CCCTAA) 3 probe and DNA staining with propidium iodide. We showed that both qPCR and Flow-FISH provide a robust measurement, with Flow-FISH measuring a relative content longer than qPCR at a single cell approach and that TRF2 fluorescence intensity did not correlate with MTC. Both methods showed comparable telomere content reduction with age, and the rate of relative telomere loss was similar. Published 2016 Wiley Periodicals Inc. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. This article is a US government work and, as such, is in the public domain in the United States of America.

Battery management system with distributed wireless sensors

DOEpatents

Farmer, Joseph C.; Bandhauer, Todd M.

2016-02-23

A system for monitoring parameters of an energy storage system having a multiplicity of individual energy storage cells. A radio frequency identification and sensor unit is connected to each of the individual energy storage cells. The radio frequency identification and sensor unit operates to sense the parameter of each individual energy storage cell and provides radio frequency transmission of the parameters of each individual energy storage cell. A management system monitors the radio frequency transmissions from the radio frequency identification and sensor units for monitoring the parameters of the energy storage system.

Infrared system for monitoring movement of objects

DOEpatents

Valentine, Kenneth H.; Falter, Diedre D.; Falter, Kelly G.

1991-01-01

A system for monitoring moving objects, such as the flight of honeybees and other insects, using a pulsed laser light source. This system has a self-powered micro-miniaturized transmitting unit powered, in the preferred embodiment, with an array solar cells. This transmitting unit is attached to the object to be monitored. These solar cells provide current to a storage energy capacitor to produce, for example, five volts for the operation of the transmitter. In the simplest embodiment, the voltage on the capacitor operates a pulse generator to provide a pulsed energizing signal to one or more very small laser diodes. The pulsed light is then received at a receiving base station using substantially standard means which converts the light to an electrical signal for processing in a microprocessor to create the information as to the movement of the object. In the case of a unit for monitoring honeybees and other insects, the transmitting unit weighs less than 50 mg, and has a size no larger than 1.times.3.times.5 millimeters. Also, the preferred embodiment provides for the coding of the light to uniquely identify the particular transmitting unit that is being monitored. A "wake-up" circuit is provided in the preferred embodiment whereby there is no transmission until the voltage on the capacitor has exceeded a pre-set threshold. Various other uses of the motion-detection system are described.

Infrared system for monitoring movement of objects

DOEpatents

Valentine, K.H.; Falter, D.D.; Falter, K.G.

1991-04-30

A system is described for monitoring moving objects, such as the flight of honeybees and other insects, using a pulsed laser light source. This system has a self-powered micro-miniaturized transmitting unit powered, in the preferred embodiment, with an array of solar cells. This transmitting unit is attached to the object to be monitored. These solar cells provide current to a storage energy capacitor to produce, for example, five volts for the operation of the transmitter. In the simplest embodiment, the voltage on the capacitor operates a pulse generator to provide a pulsed energizing signal to one or more very small laser diodes. The pulsed light is then received at a receiving base station using substantially standard means which converts the light to an electrical signal for processing in a microprocessor to create the information as to the movement of the object. In the case of a unit for monitoring honeybees and other insects, the transmitting unit weighs less than 50 mg, and has a size no larger than 1[times]3[times]5 millimeters. Also, the preferred embodiment provides for the coding of the light to uniquely identify the particular transmitting unit that is being monitored. A wake-up' circuit is provided in the preferred embodiment whereby there is no transmission until the voltage on the capacitor has exceeded a pre-set threshold. Various other uses of the motion-detection system are described. 4 figures.

New technologies for the human cytome project.

PubMed

Tárnok, A

2004-01-01

Cytomes or cell systems are composed of various kinds of single-cells and constitute the elementary building units of organs and organisms. Their individualised (cytomic) analysis overcomes the problem of averaged results from cell and tissue homogenates where molecular changes in low frequency cell populations may be hidden and wrongly interpreted. Analysis of the cytome is of pivotal importance in basic research for the understanding of cells and their interrelations in complex environments like tissues and in predictive medicine where it is a prerequisite for individualised preventive therapy. Analysis of molecular phenotypes requires instrumentation that on the one hand provides high-throughput measurement of individual cells and is on the other hand highly multiplexed, enabling the simultaneous acquisition of many parameters on the single cell level. Upcoming technology suitable to this task, such as slide based cytometry is available or under development. The realisation of cytomic technology is important for the realisation of the human cytome project.

Controlling Energy Radiations of Electromagnetic Waves via Frequency Coding Metamaterials

PubMed Central

Wu, Haotian; Liu, Shuo; Wan, Xiang; Zhang, Lei; Wang, Dan; Li, Lianlin

2017-01-01

Metamaterials are artificial structures composed of subwavelength unit cells to control electromagnetic (EM) waves. The spatial coding representation of metamaterial has the ability to describe the material in a digital way. The spatial coding metamaterials are typically constructed by unit cells that have similar shapes with fixed functionality. Here, the concept of frequency coding metamaterial is proposed, which achieves different controls of EM energy radiations with a fixed spatial coding pattern when the frequency changes. In this case, not only different phase responses of the unit cells are considered, but also different phase sensitivities are also required. Due to different frequency sensitivities of unit cells, two units with the same phase response at the initial frequency may have different phase responses at higher frequency. To describe the frequency coding property of unit cell, digitalized frequency sensitivity is proposed, in which the units are encoded with digits “0” and “1” to represent the low and high phase sensitivities, respectively. By this merit, two degrees of freedom, spatial coding and frequency coding, are obtained to control the EM energy radiations by a new class of frequency‐spatial coding metamaterials. The above concepts and physical phenomena are confirmed by numerical simulations and experiments. PMID:28932671

Proton Transports in Pure Liquid Water Characterized by Melted Ice Lattice Model

NASA Astrophysics Data System (ADS)

Jie, Binbin; Sah, Chihtang

Basic water properties have not been understood for 200 years. Our Melted Ice Lattice model accounts for the 2 basic properties of pure water, the ion product (pH) and mobilities. It has HCP primitive unit cells, each with 4H2O, based on the 1933 Bernal-Fowler model, verified by 1935 Pauling residual entropy theory of 1928-1935 Giauque experimental low temperature specific heat measurements. Our 2 ion species are point-mass protons p + and p-, for mass and electricity transport. Three protonic thermal activation energies are obtained from pH and p + and p- mobilities vs T (0-100OC). Proton transport is analyzed in 3 proton-phonon collision steps: proton detrapping by protonic phonon absorption, proton scattering by oxygenic (water) phonons, and proton trapping with protonic phonon emission. Distinction between Potential and Kinetic Energy Bands of protons (Fermions) and phonons (Bosons) is noted. Experimental protonic activation energies are the phonon energies given by the spring-mass vibration frequencies of lattice, wn = (kn/mn)1/2 . n is the proton-mass unit of the synchronized vibrating particles in the primitive unit cells.

Mechanisms governing the visco-elastic responses of living cells assessed by foam and tensegrity models.

PubMed

Cañadas, P; Laurent, V M; Chabrand, P; Isabey, D; Wendling-Mansuy, S

2003-11-01

The visco-elastic properties of living cells, measured to date by various authors, vary considerably, depending on the experimental methods and/or on the theoretical models used. In the present study, two mechanisms thought to be involved in cellular visco-elastic responses were analysed, based on the idea that the cytoskeleton plays a fundamental role in cellular mechanical responses. For this purpose, the predictions of an open unit-cell model and a 30-element visco-elastic tensegrity model were tested, taking into consideration similar properties of the constitutive F-actin. The quantitative predictions of the time constant and viscosity modulus obtained by both models were compared with previously published experimental data obtained from living cells. The small viscosity modulus values (10(0)-10(3) Pa x s) predicted by the tensegrity model may reflect the combined contributions of the spatially rearranged constitutive filaments and the internal tension to the overall cytoskeleton response to external loading. In contrast, the high viscosity modulus values (10(3)-10(5) Pa x s) predicted by the unit-cell model may rather reflect the mechanical response of the cytoskeleton to the bending of the constitutive filaments and/or to the deformation of internal components. The present results suggest the existence of a close link between the overall visco-elastic response of micromanipulated cells and the underlying architecture.

Compact fuel cell

DOEpatents

Jacobson, Craig; DeJonghe, Lutgard C.; Lu, Chun

2010-10-19

A novel electrochemical cell which may be a solid oxide fuel cell (SOFC) is disclosed where the cathodes (144, 140) may be exposed to the air and open to the ambient atmosphere without further housing. Current collector (145) extends through a first cathode on one side of a unit and over the unit through the cathode on the other side of the unit and is in electrical contact via lead (146) with housing unit (122 and 124). Electrical insulator (170) prevents electrical contact between two units. Fuel inlet manifold (134) allows fuel to communicate with internal space (138) between the anodes (154 and 156). Electrically insulating members (164 and 166) prevent the current collector from being in electrical contact with the anode.

Development of Low Cost, High Energy-Per-Unit-Area Solar Cell Modules

NASA Technical Reports Server (NTRS)

Jones, G. T.; Chitre, S.

1977-01-01

Work on the development of low cost, high energy per unit area solar cell modules was conducted. Hexagonal solar cell and module efficiencies, module packing ratio, and solar cell design calculations were made. The cell grid structure and interconnection pattern was designed and the module substrates were fabricated for the three modules to be used. It was demonstrated that surface macrostructures significantly improve cell power output and photovoltaic energy conversion efficiency.

Ab initio phasing based on topological restraints: automated determination of the space group and the number of molecules in the unit cell.

PubMed

Urzhumtseva, Ludmila; Lunina, Natalia; Fokine, Andrei; Samama, Jean Pierre; Lunin, Vladimir Y; Urzhumtsev, Alexandre

2004-09-01

The connectivity-based phasing method has been demonstrated to be capable of finding molecular packing and envelopes even for difficult cases of structure determination, as well as of identifying, in favorable cases, secondary-structure elements of protein molecules in the crystal. This method uses a single set of structure factor magnitudes and general topological features of a crystallographic image of the macromolecule under study. This information is expressed through a number of parameters. Most of these parameters are easy to estimate, and the results of phasing are practically independent of these parameters when they are chosen within reasonable limits. By contrast, the correct choice for such parameters as the expected number of connected regions in the unit cell is sometimes ambiguous. To study these dependencies, numerous tests were performed with simulated data, experimental data and mixed data sets, where several reflections missed in the experiment were completed by computed data. This paper demonstrates that the procedure is able to control this choice automatically and helps in difficult cases to identify the correct number of molecules in the asymmetric unit. In addition, the procedure behaves abnormally if the space group is defined incorrectly and therefore may distinguish between the rotation and screw axes even when high-resolution data are not available.

The molecular structure of the isopoly complex ion, decavanadate (V10O286-)

USGS Publications Warehouse

Evans, H.T.

1966-01-01

The structure of the decavanadate ion V10O286- has been found by a determination of the crystal structure of K2Zn2V10O28?? 16H2O. The soluble, orange crystals are triclinic with space group P1 and have a unit cell with a = 10.778 A, b = 11.146 A, c = 8.774 A, ?? = 104?? 57???, ?? = 109?? 3???', and ?? = 65?? 0??? (Z = 1). The structure was solved from a three-dimensional Patterson map based on 5143 Weissenberg-film data. The full-matrix, least-squares refinement gave R = 0.094 and ?? for V-O bond lengths of 0.008 A. The unit cell contains one V10O286- unit, two Zn(H2O)62+ groups, two K+ ions, and four additional water molecules. The decavanadate ion is an isolated group of ten condensed VO6 octahedra, six in a rectangular 2 x 3 array sharing edges, and four more, two fitted in above and two below by sharing sloping edges. The structure, which is based on a sodium-chloride-like arrangement of V and O atoms, has a close relationship to other isopoly complex molybdates, niobates, and tantalates. Strong distortions in the VO6 octahedra are analogous to square-pyramid and other special coordination features known in other vanadate structures.

High-voltage solar-cell chip

NASA Technical Reports Server (NTRS)

Kapoor, V. J.; Valco, G. J.; Skebe, G. G.; Evans, J. C., Jr.

1985-01-01

Integrated circuit technology has been successfully applied to the design and fabrication of 0.5 x 0.5-cm planar multijunction solar-cell chips. Each of these solar cells consisted of six voltage-generating unit cells monolithically connected in series and fabricated on a 75-micron-thick, p-type, single crystal, silicon substrate. A contact photolithic process employing five photomask levels together with a standard microelectronics batch-processing technique were used to construct the solar-cell chip. The open-circuit voltage increased rapidly with increasing illumination up to 5 AM1 suns where it began to saturate at the sum of the individual unit-cell voltages at a maximum of 3.0 V. A short-circuit current density per unit cell of 240 mA/sq cm was observed at 10 AM1 suns.

Using stochastic cell division and death to probe minimal units of cellular replication

NASA Astrophysics Data System (ADS)

Chib, Savita; Das, Suman; Venkatesan, Soumya; Sai Narain Seshasayee, Aswin; Thattai, Mukund

2018-03-01

The invariant cell initiation mass measured in bacterial growth experiments has been interpreted as a minimal unit of cellular replication. Here we argue that the existence of such minimal units induces a coupling between the rates of stochastic cell division and death. To probe this coupling we tracked live and dead cells in Escherichia coli populations treated with a ribosome-targeting antibiotic. We find that the growth exponent from macroscopic cell growth or decay measurements can be represented as the difference of microscopic first-order cell division and death rates. The boundary between cell growth and decay, at which the number of live cells remains constant over time, occurs at the minimal inhibitory concentration (MIC) of the antibiotic. This state appears macroscopically static but is microscopically dynamic: division and death rates exactly cancel at MIC but each is remarkably high, reaching 60% of the antibiotic-free division rate. A stochastic model of cells as collections of minimal replicating units we term ‘widgets’ reproduces both steady-state and transient features of our experiments. Sub-cellular fluctuations of widget numbers stochastically drive each new daughter cell to one of two alternate fates, division or death. First-order division or death rates emerge as eigenvalues of a stationary Markov process, and can be expressed in terms of the widget’s molecular properties. High division and death rates at MIC arise due to low mean and high relative fluctuations of widget number. Isolating cells at the threshold of irreversible death might allow molecular characterization of this minimal replication unit.

Naphtho[2,1-b:3,4-b']dithiophene-based bulk heterojunction solar cells: how molecular structure influences nanoscale morphology and photovoltaic properties.

PubMed

Kim, Yu Jin; Cheon, Ye Rim; Back, Jang Yeol; Kim, Yun-Hi; Chung, Dae Sung; Park, Chan Eon

2014-11-10

Organic bulk heterojunction photovoltaic devices based on a series of three naphtho[2,1-b:3,4-b']dithiophene (NDT) derivatives blended with phenyl-C71-butyric acid methyl ester were studied. These three derivatives, which have NDT units with various thiophene-chain lengths, were employed as the donor polymers. The influence of their molecular structures on the correlation between their solar-cell performances and their degree of crystallization was assessed. The grazing-incidence angle X-ray diffraction and atomic force microscopy results showed that the three derivatives exhibit three distinct nanoscale morphologies. We correlated these morphologies with the device physics by determining the J-V characteristics and the hole and electron mobilities of the devices. On the basis of our results, we propose new rules for the design of future generations of NDT-based polymers for use in bulk heterojunction solar cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for enhancing cell penetration of Gd3+-based MRI contrast agents by conjugation with hydrophobic fluorescent dyes.

PubMed

Yamane, Takehiro; Hanaoka, Kenjiro; Muramatsu, Yasuaki; Tamura, Keita; Adachi, Yusuke; Miyashita, Yasushi; Hirata, Yasunobu; Nagano, Tetsuo

2011-11-16

Gadolinium ion (Gd(3+)) complexes are commonly used as magnetic resonance imaging (MRI) contrast agents to enhance signals in T(1)-weighted MR images. Recently, several methods to achieve cell-permeation of Gd(3+) complexes have been reported, but more general and efficient methodology is needed. In this report, we describe a novel method to achieve cell permeation of Gd(3+) complexes by using hydrophobic fluorescent dyes as a cell-permeability-enhancing unit. We synthesized Gd(3+) complexes conjugated with boron dipyrromethene (BDP-Gd) and Cy7 dye (Cy7-Gd), and showed that these conjugates can be introduced efficiently into cells. To examine the relationship between cell permeability and dye structure, we further synthesized a series of Cy7-Gd derivatives. On the basis of MR imaging, flow cytometry, and ICP-MS analysis of cells loaded with Cy7-Gd derivatives, highly hydrophobic and nonanionic dyes were effective for enhancing cell permeation of Gd(3+) complexes. Furthermore, the behavior of these Cy7-Gd derivatives was examined in mice. Thus, conjugation of hydrophobic fluorescent dyes appears to be an effective approach to improve the cell permeability of Gd(3+) complexes, and should be applicable for further development of Gd(3+)-based MRI contrast agents.

Development and validation of a rapid, aldehyde dehydrogenase bright-based cord blood potency assay.

PubMed

Shoulars, Kevin; Noldner, Pamela; Troy, Jesse D; Cheatham, Lynn; Parrish, Amanda; Page, Kristin; Gentry, Tracy; Balber, Andrew E; Kurtzberg, Joanne

2016-05-12

Banked, unrelated umbilical cord blood provides access to hematopoietic stem cell transplantation for patients lacking matched bone marrow donors, yet 10% to 15% of patients experience graft failure or delayed engraftment. This may be due, at least in part, to inadequate potency of the selected cord blood unit (CBU). CBU potency is typically assessed before cryopreservation, neglecting changes in potency occurring during freezing and thawing. Colony-forming units (CFUs) have been previously shown to predict CBU potency, defined as the ability to engraft in patients by day 42 posttransplant. However, the CFU assay is difficult to standardize and requires 2 weeks to perform. Consequently, we developed a rapid multiparameter flow cytometric CBU potency assay that enumerates cells expressing high levels of the enzyme aldehyde dehydrogenase (ALDH bright [ALDH(br)]), along with viable CD45(+) or CD34(+) cell content. These measurements are made on a segment that was attached to a cryopreserved CBU. We validated the assay with prespecified criteria testing accuracy, specificity, repeatability, intermediate precision, and linearity. We then prospectively examined the correlations among ALDH(br), CD34(+), and CFU content of 3908 segments over a 5-year period. ALDH(br) (r = 0.78; 95% confidence interval [CI], 0.76-0.79), but not CD34(+) (r = 0.25; 95% CI, 0.22-0.28), was strongly correlated with CFU content as well as ALDH(br) content of the CBU. These results suggest that the ALDH(br) segment assay (based on unit characteristics measured before release) is a reliable assessment of potency that allows rapid selection and release of CBUs from the cord blood bank to the transplant center for transplantation. © 2016 by The American Society of Hematology.

Development and validation of a rapid, aldehyde dehydrogenase bright–based cord blood potency assay

PubMed Central

Noldner, Pamela; Troy, Jesse D.; Cheatham, Lynn; Parrish, Amanda; Page, Kristin; Gentry, Tracy; Balber, Andrew E.; Kurtzberg, Joanne

2016-01-01

Banked, unrelated umbilical cord blood provides access to hematopoietic stem cell transplantation for patients lacking matched bone marrow donors, yet 10% to 15% of patients experience graft failure or delayed engraftment. This may be due, at least in part, to inadequate potency of the selected cord blood unit (CBU). CBU potency is typically assessed before cryopreservation, neglecting changes in potency occurring during freezing and thawing. Colony-forming units (CFUs) have been previously shown to predict CBU potency, defined as the ability to engraft in patients by day 42 posttransplant. However, the CFU assay is difficult to standardize and requires 2 weeks to perform. Consequently, we developed a rapid multiparameter flow cytometric CBU potency assay that enumerates cells expressing high levels of the enzyme aldehyde dehydrogenase (ALDH bright [ALDHbr]), along with viable CD45+ or CD34+ cell content. These measurements are made on a segment that was attached to a cryopreserved CBU. We validated the assay with prespecified criteria testing accuracy, specificity, repeatability, intermediate precision, and linearity. We then prospectively examined the correlations among ALDHbr, CD34+, and CFU content of 3908 segments over a 5-year period. ALDHbr (r = 0.78; 95% confidence interval [CI], 0.76-0.79), but not CD34+ (r = 0.25; 95% CI, 0.22-0.28), was strongly correlated with CFU content as well as ALDHbr content of the CBU. These results suggest that the ALDHbr segment assay (based on unit characteristics measured before release) is a reliable assessment of potency that allows rapid selection and release of CBUs from the cord blood bank to the transplant center for transplantation. PMID:26968535

Perylene-Diimide Based Donor-Acceptor-Donor Type Small-Molecule Acceptors for Solution-Processable Organic Solar Cells

NASA Astrophysics Data System (ADS)

Ganesamoorthy, Ramasamy; Vijayaraghavan, Rajagopalan; Sakthivel, Pachagounder

2017-12-01

Development of nonfullerene acceptors plays an important role in the commercial availability of plastic solar cells. We report herein synthesis of bay-substituted donor-acceptor-donor (D-A-D)-type perylene diimide (PDI)-based small molecules (SM-1 to SM-4) by Suzuki coupling method and their use as acceptors in bulk heterojunction organic solar cells (BHJ-OSCs) with poly(3-hexylthiophene) (P3HT) polymer donor. We varied the number of electron-rich thiophene units and the solubilizing side chains and also evaluated the optical and electrochemical properties of the small molecules. The synthesized small molecules were confirmed by Fourier-transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and high-resolution mass spectroscopy (HR-MS). The small molecules showed extensive and strong absorption in the ultraviolet-visible (UV-Vis) region up to 750 nm, with bandgap (E_{{g}}^{{opt}} ) reduced below <2 eV. The energy levels of small molecules SM-1 to SM-4 were suitable for use as electron-accepting materials. The small molecules showed good thermal stability up to 300°C. BHJ-OSCs with SM-1 and P3HT polymer donor showed maximum power conversion efficiency (PCE) of 0.19% with V oc of 0.30 V, J sc of 1.72 mA cm-2, and fill factor (FF) of 37%. The PCE decreased with the number of thiophene units. The PCE of SM-2 was lower than that of SM-1. This difference in PCE can be explained by the higher aggregation tendency of the bithiophene compared with the thiophene unit. Introduction of the solubilizing group in the bay position increased the aggregation property, leading to much lower PCE than for the small molecules without solubilizing group.

Identification of a constitutive law for trabecular bone samples under remodeling in the framework of irreversible thermodynamics

NASA Astrophysics Data System (ADS)

Louna, Zineeddine; Goda, Ibrahim; Ganghoffer, Jean-François

2018-01-01

We construct in the present paper constitutive models for bone remodeling based on micromechanical analyses at the scale of a representative unit cell (RUC) including a porous trabecular microstructure. The time evolution of the microstructure is simulated as a surface remodeling process by relating the surface growth remodeling velocity to a surface driving force incorporating a (surface) Eshelby tensor. Adopting the framework of irreversible thermodynamics, a 2D constitutive model based on the setting up of the free energy density and a dissipation potential is identified from FE simulations performed over a unit cell representative of the trabecular architecture obtained from real bone microstructures. The static and evolutive effective properties of bone at the scale of the RUC are obtained by combining a methodology for the evaluation of the average kinematic and static variables over a prototype unit cell and numerical simulations with controlled imposed first gradient rates. The formulated effective growth constitutive law at the scale of the homogenized set of trabeculae within the RUC is of viscoplastic type and relates the average growth strain rate to the homogenized stress tensor. The postulated model includes a power law function of an effective stress chosen to depend on the first and second stress invariants. The model coefficients are calibrated from a set of virtual testing performed over the RUC subjected to a sequence of loadings. Numerical simulations show that overall bone growth does not show any growth kinematic hardening. The obtained results quantify the strength and importance of different types of external loads (uniaxial tension, simple shear, and biaxial loading) on the overall remodeling process and the development of elastic deformations within the RUC.

Requirement of the actin cytoskeleton for the association of nectins with other cell adhesion molecules at adherens and tight junctions in MDCK cells.

PubMed

Yamada, Akio; Irie, Kenji; Fukuhara, Atsunori; Ooshio, Takako; Takai, Yoshimi

2004-09-01

Nectins, Ca(2+)-independent immunoglobulin-like cell adhesion molecules (CAMs), first form cell-cell adhesion where cadherins are recruited, forming adherens junctions (AJs) in epithelial cells and fibroblasts. In addition, nectins recruit claudins, occludin, and junctional adhesion molecules (JAMs) to the apical side of AJs, forming tight junctions (TJs) in epithelial cells. Nectins are associated with these CAMs through peripheral membrane proteins (PMPs), many of which are actin filament-binding proteins. We examined here the roles of the actin cytoskeleton in the association of nectins with other CAMs in MDCK cells stably expressing exogenous nectin-1. The nectin-1-based cell-cell adhesion was formed and maintained irrespective of the presence and absence of the actin filament-disrupting agents, such as cytochalasin D and latrunculin A. In the presence of these agents, only afadin remained at the nectin-1-based cell-cell adhesion sites, whereas E-cadherin and other PMPs at AJs, alpha-catenin, beta-catenin, vinculin, alpha-actinin, ADIP, and LMO7, were not concentrated there. The CAMs at TJs, claudin-1, occludin and JAM-1, or the PMPs at TJs, ZO-1 and MAGI-1, were not concentrated there, either. These results indicate that the actin cytoskeleton is required for the association of the nectin-afadin unit with other CAMs and PMPs at AJs and TJs.

42 CFR 410.161 - Part B blood deductible.

Code of Federal Regulations, 2013 CFR

2013-10-01

... deductible. (a) General rules. (1) As used in this section, packed red cells means the red blood cells that remain after plasma is separated from whole blood. (2) A unit of packed red cells is treated as the... beneficiary is responsible for the first three units of whole blood or packed red cells received during a...

42 CFR 410.161 - Part B blood deductible.

Code of Federal Regulations, 2012 CFR

2012-10-01

... deductible. (a) General rules. (1) As used in this section, packed red cells means the red blood cells that remain after plasma is separated from whole blood. (2) A unit of packed red cells is treated as the... beneficiary is responsible for the first three units of whole blood or packed red cells received during a...

42 CFR 410.161 - Part B blood deductible.

Code of Federal Regulations, 2014 CFR

2014-10-01

... deductible. (a) General rules. (1) As used in this section, packed red cells means the red blood cells that remain after plasma is separated from whole blood. (2) A unit of packed red cells is treated as the... beneficiary is responsible for the first three units of whole blood or packed red cells received during a...

42 CFR 410.161 - Part B blood deductible.

Code of Federal Regulations, 2011 CFR

2011-10-01

... deductible. (a) General rules. (1) As used in this section, packed red cells means the red blood cells that remain after plasma is separated from whole blood. (2) A unit of packed red cells is treated as the... beneficiary is responsible for the first three units of whole blood or packed red cells received during a...

Adipose Stromal Vascular Fraction Isolation: A Head-to-Head Comparison of 4 Cell Separation Systems #2.

PubMed

Aronowitz, Joel A; Lockhart, Ryan A; Hakakian, Cloe S; Birnbaum, Zoe E

2016-09-01

With stromal vascular fraction (SVF) cell and adipose-derived stem cell-based technologies translating into the clinical setting, numerous isolation systems have been developed for the point of care isolation of SVF cells from adipose tissue. A relative lack of performance data on these systems can make objective assessment difficult for prospective clinicians. This study compared the performance of 4 SVF cell isolation systems. Four isolation systems were compared: the MultiStation by PNC International, the LipoKit by MediKhan, the GID SVF-2 platform by GID Europe Ltd, and the StemSource 900/MB system by Cytori Therapeutics, Inc. Identical lipoaspirate samples for 5 separate donors were used. Stromal vascular fraction output was compared in terms of nucleated cell yield, viability, residual collagenase activity, sterility of the output, colony-forming unit-fibroblast frequency, frequency of CD31-/CD34+/CD45- cells, and operating statistics. Mean process time ranged from 65.4 to 120.8 minutes. Mean nucleated cell yield per milliliter of tissue processed ranged from 1.01 × 10 cells/mL to 6.24 × 10 cells/mL. Mean cellular viability ranged from 50.3% to 84.02%. Residual collagenase activity was negligible across all systems. Observed colony-forming unit-fibroblast frequency ranged from 0.495% to 1.704%. No significant difference was observed in frequency of CD31-/CD34+/CD45- cells. Results of the anaerobic/aerobic cultures were mixed. There was considerable variability between the outputs of each system. The system used by a clinician should be tailored to the individual needs of the practice. There is a range of cost options available. This study may help clinicians make more educated decisions when choosing an isolation system to meet their clinical needs.

Establishment of an unrelated umbilical cord blood bank qualification program: ensuring quality while meeting Food and Drug Administration vendor qualification requirements.

PubMed

Rabe, Fran; Kadidlo, Diane; Van Orsow, Lisa; McKenna, David

2013-10-01

Qualification of a cord blood bank (CBB) is a complex process that includes evaluation of multiple aspects of donor screening and testing, processing, accreditation and approval by professional cell therapy groups, and results of received cord blood units. The University of Minnesota Medical Center Cell Therapy Laboratory has established a CBB vendor qualification process to ensure the CBB meets established regulatory and quality requirements. The deployed qualification of CBBs is based on retrospective and prospective review of the CBB. Forty-one CBBs were evaluated retrospectively: seven CBBs were disqualified based on failed quality control (QC) results. Eight CBBs did not meet the criteria for retrospective qualification because fewer than 3 cord blood units were received and the CBB was not accredited. As of March 2012, three US and one non-US CBBs have been qualified prospectively. One CBB withdrew from the qualification process after successful completion of the comprehensive survey and subsequent failure of the provided QC unit to pass the minimum criteria. One CBB failed the prospective qualification process based on processing methods that were revealed during the paper portion of the evaluation. A CBB qualification process is necessary for a transplant center to manage the qualification of the large number of CBBs needed to support a umbilical cord blood transplantation program. A transplant center that has utilized cord blood for a number of years before implementation of a qualification process should use a retrospective qualification process along with a prospective process. © 2013 American Association of Blood Banks.

Method and apparatus for adding electrolyte to a fuel cell stack

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congdon, J.V.; English, J.G.

1986-06-24

A process is described for adding electrolyte to a fuel cell stack, the stack comprising sheet-like elements defining a plurality of fuel cell units disposed one atop the other in abutting relationship, the units defining a substantially flat, vertically extending face, each unit including a cell comprising a pair of sheet-like spaced apart gas porous electrodes with a porous matrix layer sandwiched therebetween for retaining electrolyte during cell operation, each unit also including a sheet-like substantially non-porous separator, the separator being sandwiched between the cells of adjacent units. The improvement described here consists of: extending at least one of themore » sheet-like elements of each of a plurality of the fuel cell units outwardly from the stack face to define horizontal tabs disposed one above the other; depositing dilute electrolyte directly from electrolyte supply means upon substantially the full length, parallel to the stack face, of at least the uppermost tab, the tabs being constructed and arranged such that at least a portion of the deposited electrolyte cascades from tab to tab and down the face of the stack, the deposited electrolyte being absorbed by capillary action into the elements of the stack, the step of depositing continuing until all of the electrodes and matrix layers of the stack are fully saturated with the dilute electrolyte; and thereafter evaporating liquid from the saturated elements under controlled conditions of humidity and temperature until the stack has a desired electrolyte volume and electrolyte concentration therein.« less

Expression of N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase involved in chondroitin sulfate synthesis is responsible for pulmonary metastasis.

PubMed

Mizumoto, Shuji; Watanabe, Moto; Yamada, Shuhei; Sugahara, Kazuyuki

2013-01-01

Chondroitin sulfate (CS) containing E-disaccharide units, glucuronic acid-N-acetylgalactosamine(4, 6-O-disulfate), at surfaces of tumor cells plays a key role in tumor metastasis. However, the molecular mechanism of the metastasis involving the CS chain-containing E-units is not fully understood. In this study, to clarify the role of E-units in the metastasis and to search for potential molecular targets for anticancer drugs, the isolation and characterization of Lewis lung carcinoma (LLC) cells stably downregulated by the knockdown for the gene encoding N-acetylgalactosamine 4-O-sulfate 6-O-sulfotransferase (GalNAc4S-6ST), which is responsible for the formation of E-units in CS chains, were performed. Knockdown of GalNAc4S-6ST in LLC cells resulted in a reduction in the proportion of E-units, in adhesiveness to extracellular matrix adhesion molecules and in proliferation in vitro. Furthermore, the stable downregulation of GalNAc4S-6ST expression in LLC cells markedly inhibited the colonization of the lungs by inoculated LLC cells and invasive capacity of LLC cells. These results provide clear evidence that CS chain-containing E-units and/or GalNAc4S-6ST play a crucial role in pulmonary metastasis at least through the increased adhesion and the invasive capacity of LLC cells and also provides insights into future drug targets for anticancer treatment.

The pluralization of the international: Resistance and alter-standardization in regenerative stem cell medicine

PubMed Central

Rosemann, Achim; Chaisinthop, Nattaka

2016-01-01

The article explores the formation of an international politics of resistance and ‘alter-standardization’ in regenerative stem cell medicine. The absence of internationally harmonized regulatory frameworks in the clinical stem cell field and the presence of lucrative business opportunities have resulted in the formation of transnational networks adopting alternative research standards and practices. These oppose, as a universal global standard, strict evidence-based medicine clinical research protocols as defined by scientists and regulatory agencies in highly developed countries. The emergence of transnational spaces of alter-standardization is closely linked to scientific advances in rapidly developing countries such as China and India, but calls for more flexible regulatory frameworks, and the legitimization of experimental for-profit applications outside of evidence-based medical care, are emerging increasingly also within more stringently regulated countries, such as the United States and countries in the European Union. We can observe, then, a trend toward the pluralization of the standards, practices, and concepts in the stem cell field. PMID:26983174

Hydrogen Learning for Local Leaders – H2L3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serfass, Patrick

The Hydrogen Learning for Local Leaders program, H2L3, elevates the knowledge about hydrogen by local government officials across the United States. The program reaches local leaders directly through “Hydrogen 101” workshops and webinar sessions; the creation and dissemination of a unique report on the hydrogen and fuel cell market in the US, covering 57 different sectors; and support of the Hydrogen Student Design Contest, a competition for interdisciplinary teams of university students to design hydrogen and fuel cell systems based on technology that’s currently commercially available.

Reciprocal links between metabolic and ionic events in islet cells. Their relevance to the rhythmics of insulin release.

PubMed

Malaisse, W J

1998-02-01

The notion of reciprocal links between metabolic and ionic events in islet cells and the rhythmics of insulin release is based on (i) the rhythmic pattern of hormonal release from isolated perfused rat pancreas, which supports the concept of an intrapancreatic pacemaker; (ii) the assumption that this phasic pattern is due to the integration of secretory activity in distinct functional units, e.g. distinct islets; and (iii) the fact that reciprocal coupling between metabolic and ionic events is operative in the secretory sequence.

3D high- and super-resolution imaging using single-objective SPIM.

PubMed

Galland, Remi; Grenci, Gianluca; Aravind, Ajay; Viasnoff, Virgile; Studer, Vincent; Sibarita, Jean-Baptiste

2015-07-01

Single-objective selective-plane illumination microscopy (soSPIM) is achieved with micromirrored cavities combined with a laser beam-steering unit installed on a standard inverted microscope. The illumination and detection are done through the same objective. soSPIM can be used with standard sample preparations and features high background rejection and efficient photon collection, allowing for 3D single-molecule-based super-resolution imaging of whole cells or cell aggregates. Using larger mirrors enabled us to broaden the capabilities of our system to image Drosophila embryos.

Detection and quantification of subtle changes in red blood cell density using a cell phone.

PubMed

Felton, Edward J; Velasquez, Anthony; Lu, Shulin; Murphy, Ryann O; ElKhal, Abdala; Mazor, Ofer; Gorelik, Pavel; Sharda, Anish; Ghiran, Ionita C

2016-08-16

Magnetic levitation has emerged as a technique that offers the ability to differentiate between cells with different densities. We have developed a magnetic levitation system for this purpose that distinguishes not only different cell types but also density differences in cells of the same type. This small-scale system suspends cells in a paramagnetic medium in a capillary placed between two rare earth magnets, and cells levitate to an equilibrium position determined solely by their density. Uniform reference beads of known density are used in conjunction with the cells as a means to quantify their levitation positions. In one implementation images of the levitating cells are acquired with a microscope, but here we also introduce a cell phone-based device that integrates the magnets, capillary, and a lens into a compact and portable unit that acquires images with the phone's camera. To demonstrate the effectiveness of magnetic levitation in cell density analysis we carried out levitation experiments using red blood cells with artificially altered densities, and also levitated those from donors. We observed that we can distinguish red blood cells of an anemic donor from those that are healthy. Since a plethora of disease states are characterized by changes in cell density magnetic cell levitation promises to be an effective tool in identifying and analyzing pathologic states. Furthermore, the low cost, portability, and ease of use of the cell phone-based system may potentially lead to its deployment in low-resource environments.

Measurement of the Extracellular pH of Adherently Growing Mammalian Cells with High Spatial Resolution Using a Voltammetric pH Microsensor.

PubMed

Munteanu, Raluca-Elena; Stǎnicǎ, Luciana; Gheorghiu, Mihaela; Gáspár, Szilveszter

2018-05-15

There are only a few tools suitable for measuring the extracellular pH of adherently growing mammalian cells with high spatial resolution, and none of them is widely used in laboratories around the world. Cell biologists very often limit themselves to measuring the intracellular pH with commercially available fluorescent probes. Therefore, we built a voltammetric pH microsensor and investigated its suitability for monitoring the extracellular pH of adherently growing mammalian cells. The voltammetric pH microsensor consisted of a 37 μm diameter carbon fiber microelectrode modified with reduced graphene oxide and syringaldazine. While graphene oxide was used to increase the electrochemically active surface area of our sensor, syringaldazine facilitated pH sensing through its pH-dependent electrochemical oxidation and reduction. The good sensitivity (60 ± 2.5 mV/pH unit), reproducibility (coefficient of variation ≤3% for the same pH measured with 5 different microsensors), and stability (pH drift around 0.05 units in 3 h) of the built voltammetric pH sensors were successfully used to investigate the acidification of the extracellular space of both cancer cells and normal cells. The results indicate that the developed pH microsensor and the perfected experimental protocol based on scanning electrochemical microscopy can reveal details of the pH regulation of cells not attainable with pH sensors lacking spatial resolution or which cannot be reproducibly positioned in the extracellular space.

Reprogramming primordial germ cells (PGC) to embryonic germ (EG) cells.

PubMed

Durcova-Hills, Gabriela; Surani, Azim

2008-04-01

In this unit we describe the derivation of pluripotent embryonic germ (EG) cells from mouse primordial germ cells (PGCs) isolated from both 8.5- and 11.5-days post-coitum (dpc) embryos. Once EG cells are derived we explain how to propagate and characterize the cell lines. We introduce readers to PGCs and explain differences between PGCs and their in vitro derivatives EG cells. Finally, we also compare mouse EG cells with ES cells. This unit will be of great interest to anyone interested in PGCs or studying the behavior of cultured PGCs or the derivation of new EG cell lines.

Novel hydroxyamides and amides containing D-glucopyranose or D-fructose units: Biological assays in MCF-7 and MDST8 cell lines.

PubMed

Carreiro, Elisabete P; Costa, Ana R; Cordeiro, Maria M; Martins, Rute; Pires, Tiago O; Saraiva, Mafalda; Antunes, Célia M; Burke, Anthony J

2016-02-01

A novel library of 15 compounds, hydroxyamides and amides containing a β-D-glucopyranose (D-Gluc) or a β-D-fructose (D-Fruc) units was designed and synthesized for antiproliferative assays in breast (MCF-7) and colon (MDST8) cancer cell lines. Twelve of them were hydroxyamides and were successfully synthesized from β-D-glucuronic acid (D-GluA). Six of these hydroxyamides which were acetylated hydroxy-β-D-glucopyranuronamide 2a-2f (1st Family) and the other six were their respective isomers, that is, hydroxy-β-D-fructuronamide 3a-3f (2nd Family), obtained by acid-base catalyzed isomerization. These compounds have the general structure, D-Gluc-C=ONH-CHR-(CH2)n-OH and D-Fruc-C=ONH-CHR-(CH2)n-OH, where R=an aromatic, alkyl or a hydrogen substituent, with n=0 or 1. Eight of these contained a chiral aminoalcohol group. Three compounds were amides containing a D-glucopyranose unit (3rd Family). SAR studies were conducted with these compounds. Antiproliferative studies showed that compound 4a, the bromo-amide containing the β-D-glucopyranose ring, potently inhibits the proliferation of the MDST8 cells. Five compounds (2e, 2f, 3d, 3e, and 3f) were shown to potently selectively inhibit the proliferation of the MCF-7 cells. Compound 4b was the only one showing inhibition in both cell lines. In general, the more active compounds were the amides and hydroxyamides containing the β-D-fructose moiety, and containing an alkyl group or hydrogen. Half-inhibitory concentrations (IC50) of between 0.01 and 10 μM, were observed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Substantivity of hypochlorous acid-based disinfectant against biofilm formation in the dental unit waterlines

PubMed Central

Shajahan, Irfana Fathima; Kandaswamy, Deivanayagam; Lakshminarayanan, L.; Selvarajan, R.

2017-01-01

Objective: The purpose of the study was to examine the substantivity of a new disinfectant against biofilm formation in the dental unit waterlines. Materials and Methods: Twenty dental units were selected for the study and divided into two groups: Group A (dental unit waterlines treated with the disinfectant) and Group B (untreated dental unit waterlines). Biofilm formation was monitored in both groups by removing the one dental unit waterline from each group for the period of 10 days. One inch of the dental unit waterline tube was cut at random site, and the inner lumen of the cut sections was analyzed using the scanning electron microscope (SEM) (TESCAN VEGA3 SBU). Results: On examination, SEM images showed that there was no slime layer or bacterial cells seen in cut section for the period of 7 days in the treated dental waterlines, which means that there is no evident of biofilm formation. In the untreated dental unit waterline cut section, slime layer was observed from day 1. Conclusion: Disinfectant solution was proved to be effective for 7 days against biofilm formation. This technique could be used as a valid method for disinfection of dental unit waterlines. PMID:28761244

Crystallization and preliminary X-ray diffraction studies of trypsin-like proteases from the gastric fluid of the marine crab Cancer pagurus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hehemann, Jan-Hendrik; Redecke, Lars; Perbandt, Markus

2007-03-01

Two trypsins from the gastric fluid of the marine crab C. pagurus were purified and crystallized and X-ray data were collected to 0.97 and 3.2 Å resolution. The digestive fluid of the marine crab Cancer pagurus (Decapoda, Brachyura) contains highly stable proteases which display enhanced activity in aqueous mixtures of organic solvents. Three trypsins were isolated from the gastric fluid and two of them, C.p.TryII and C.p.TryIII, were purified to homogeneity by anion-exchange chromatography and crystallized by hanging-drop vapour diffusion. Diffraction data were collected at a synchrotron to 0.97 and 3.2 Å resolution, respectively. The crystal of C.p.TryII belongs tomore » the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 52.06, b = 62.00, c = 71.66 Å. Based on the Matthews coefficient, one protein molecule per asymmetric unit is suggested. In contrast, crystals of C.p.TryIII, which belong to the cubic space group P2{sub 1}3 with unit-cell parameters a = b = c = 215.4 Å, are assumed to contain 12 molecules per asymmetric unit.« less

Digital Microfluidics for Manipulation and Analysis of a Single Cell.

PubMed

He, Jie-Long; Chen, An-Te; Lee, Jyong-Huei; Fan, Shih-Kang

2015-09-15

The basic structural and functional unit of a living organism is a single cell. To understand the variability and to improve the biomedical requirement of a single cell, its analysis has become a key technique in biological and biomedical research. With a physical boundary of microchannels and microstructures, single cells are efficiently captured and analyzed, whereas electric forces sort and position single cells. Various microfluidic techniques have been exploited to manipulate single cells through hydrodynamic and electric forces. Digital microfluidics (DMF), the manipulation of individual droplets holding minute reagents and cells of interest by electric forces, has received more attention recently. Because of ease of fabrication, compactness and prospective automation, DMF has become a powerful approach for biological application. We review recent developments of various microfluidic chips for analysis of a single cell and for efficient genetic screening. In addition, perspectives to develop analysis of single cells based on DMF and emerging functionality with high throughput are discussed.

Digital Microfluidics for Manipulation and Analysis of a Single Cell

PubMed Central

He, Jie-Long; Chen, An-Te; Lee, Jyong-Huei; Fan, Shih-Kang

2015-01-01

The basic structural and functional unit of a living organism is a single cell. To understand the variability and to improve the biomedical requirement of a single cell, its analysis has become a key technique in biological and biomedical research. With a physical boundary of microchannels and microstructures, single cells are efficiently captured and analyzed, whereas electric forces sort and position single cells. Various microfluidic techniques have been exploited to manipulate single cells through hydrodynamic and electric forces. Digital microfluidics (DMF), the manipulation of individual droplets holding minute reagents and cells of interest by electric forces, has received more attention recently. Because of ease of fabrication, compactness and prospective automation, DMF has become a powerful approach for biological application. We review recent developments of various microfluidic chips for analysis of a single cell and for efficient genetic screening. In addition, perspectives to develop analysis of single cells based on DMF and emerging functionality with high throughput are discussed. PMID:26389890

Self-Powered Wireless Carbohydrate/Oxygen Sensitive Biodevice Based on Radio Signal Transmission

PubMed Central

Falk, Magnus; Alcalde, Miguel; Bartlett, Philip N.; De Lacey, Antonio L.; Gorton, Lo; Gutierrez-Sanchez, Cristina; Haddad, Raoudha; Kilburn, Jeremy; Leech, Dónal; Ludwig, Roland; Magner, Edmond; Mate, Diana M.; Conghaile, Peter Ó.; Ortiz, Roberto; Pita, Marcos; Pöller, Sascha; Ruzgas, Tautgirdas; Salaj-Kosla, Urszula; Schuhmann, Wolfgang; Sebelius, Fredrik; Shao, Minling; Stoica, Leonard; Sygmund, Cristoph; Tilly, Jonas; Toscano, Miguel D.; Vivekananthan, Jeevanthi; Wright, Emma; Shleev, Sergey

2014-01-01

Here for the first time, we detail self-contained (wireless and self-powered) biodevices with wireless signal transmission. Specifically, we demonstrate the operation of self-sustained carbohydrate and oxygen sensitive biodevices, consisting of a wireless electronic unit, radio transmitter and separate sensing bioelectrodes, supplied with electrical energy from a combined multi-enzyme fuel cell generating sufficient current at required voltage to power the electronics. A carbohydrate/oxygen enzymatic fuel cell was assembled by comparing the performance of a range of different bioelectrodes followed by selection of the most suitable, stable combination. Carbohydrates (viz. lactose for the demonstration) and oxygen were also chosen as bioanalytes, being important biomarkers, to demonstrate the operation of the self-contained biosensing device, employing enzyme-modified bioelectrodes to enable the actual sensing. A wireless electronic unit, consisting of a micropotentiostat, an energy harvesting module (voltage amplifier together with a capacitor), and a radio microchip, were designed to enable the biofuel cell to be used as a power supply for managing the sensing devices and for wireless data transmission. The electronic system used required current and voltages greater than 44 µA and 0.57 V, respectively to operate; which the biofuel cell was capable of providing, when placed in a carbohydrate and oxygen containing buffer. In addition, a USB based receiver and computer software were employed for proof-of concept tests of the developed biodevices. Operation of bench-top prototypes was demonstrated in buffers containing different concentrations of the analytes, showcasing that the variation in response of both carbohydrate and oxygen biosensors could be monitored wirelessly in real-time as analyte concentrations in buffers were changed, using only an enzymatic fuel cell as a power supply. PMID:25310190

Self-powered wireless carbohydrate/oxygen sensitive biodevice based on radio signal transmission.

PubMed

Falk, Magnus; Alcalde, Miguel; Bartlett, Philip N; De Lacey, Antonio L; Gorton, Lo; Gutierrez-Sanchez, Cristina; Haddad, Raoudha; Kilburn, Jeremy; Leech, Dónal; Ludwig, Roland; Magner, Edmond; Mate, Diana M; Conghaile, Peter Ó; Ortiz, Roberto; Pita, Marcos; Pöller, Sascha; Ruzgas, Tautgirdas; Salaj-Kosla, Urszula; Schuhmann, Wolfgang; Sebelius, Fredrik; Shao, Minling; Stoica, Leonard; Sygmund, Cristoph; Tilly, Jonas; Toscano, Miguel D; Vivekananthan, Jeevanthi; Wright, Emma; Shleev, Sergey

2014-01-01

Here for the first time, we detail self-contained (wireless and self-powered) biodevices with wireless signal transmission. Specifically, we demonstrate the operation of self-sustained carbohydrate and oxygen sensitive biodevices, consisting of a wireless electronic unit, radio transmitter and separate sensing bioelectrodes, supplied with electrical energy from a combined multi-enzyme fuel cell generating sufficient current at required voltage to power the electronics. A carbohydrate/oxygen enzymatic fuel cell was assembled by comparing the performance of a range of different bioelectrodes followed by selection of the most suitable, stable combination. Carbohydrates (viz. lactose for the demonstration) and oxygen were also chosen as bioanalytes, being important biomarkers, to demonstrate the operation of the self-contained biosensing device, employing enzyme-modified bioelectrodes to enable the actual sensing. A wireless electronic unit, consisting of a micropotentiostat, an energy harvesting module (voltage amplifier together with a capacitor), and a radio microchip, were designed to enable the biofuel cell to be used as a power supply for managing the sensing devices and for wireless data transmission. The electronic system used required current and voltages greater than 44 µA and 0.57 V, respectively to operate; which the biofuel cell was capable of providing, when placed in a carbohydrate and oxygen containing buffer. In addition, a USB based receiver and computer software were employed for proof-of concept tests of the developed biodevices. Operation of bench-top prototypes was demonstrated in buffers containing different concentrations of the analytes, showcasing that the variation in response of both carbohydrate and oxygen biosensors could be monitored wirelessly in real-time as analyte concentrations in buffers were changed, using only an enzymatic fuel cell as a power supply.

Realization of compact tractor beams using acoustic delay-lines

NASA Astrophysics Data System (ADS)

Marzo, A.; Ghobrial, A.; Cox, L.; Caleap, M.; Croxford, A.; Drinkwater, B. W.

2017-01-01

A method for generating stable ultrasonic levitation of physical matter in air using single beams (also known as tractor beams) is demonstrated. The method encodes the required phase modulation in passive unit cells into which the ultrasonic sources are mounted. These unit cells use waveguides such as straight and coiled tubes to act as delay-lines. It is shown that a static tractor beam can be generated using a single electrical driving signal, and a tractor beam with one-dimensional movement along the propagation direction can be created with two signals. Acoustic tractor beams capable of holding millimeter-sized polymer particles of density 1.25 g/cm3 and fruit-flies (Drosophila) are demonstrated. Based on these design concepts, we show that portable tractor beams can be constructed with simple components that are readily available and easily assembled, enabling applications in industrial contactless manipulation and biophysics.

Multi-port power router and its impact on resilient power grid systems

NASA Astrophysics Data System (ADS)

Kado, Yuichi; Iwatsuki, Katsumi; Wada, Keiji

2016-02-01

We propose a Y-configuration power router as a unit cell to easily construct a power delivery system that can meet many types of user requirements. The Y-configuration power router controls the direction and magnitude of power flow among three ports regardless of DC and AC. We constructed a prototype three-way isolated DC/DC converter that is the core unit of the Y-configuration power router and tested the power flow control operation. Experimental results revealed that our methodology based on the governing equation was appropriate for the power flow control of the three-way DC/DC converter. In addition, the hexagonal distribution network composed of the power routers has the ability to easily interchange electric power between autonomous microgrid cells. We also explored the requirements for communication between energy routers to achieve dynamic adjustments of energy flow in a coordinated manner and its impact on resilient power grid systems.

Harnessing Multiple Internal Reflections to Design Highly Absorptive Acoustic Metasurfaces

NASA Astrophysics Data System (ADS)

Shen, Chen; Cummer, Steven A.

2018-05-01

The rapid development of metasurfaces has enabled numerous intriguing applications with acoustically thin sheets. Here we report the theory and experimental realization of a nonresonant sound-absorbing strategy using metasurfaces by harnessing multiple internal reflections. We theoretically and numerically show that the higher-order diffraction of thin gradient-index metasurfaces is tied to multiple internal reflections inside the unit cells. Highly absorbing acoustic metasurfaces can be realized by enforcing multiple internal reflections together with a small amount of loss. A reflective gradient-index acoustic metasurface is designed based on the theory, and we further experimentally verify the performance using a three-dimensional printed prototype. Measurements show over 99% energy absorption at the peak frequency and a 95% energy absorption bandwidth of around 600 Hz. The proposed mechanism provides an alternative route for sound absorption without the necessity of high absorption of the individual unit cells.

Physically elastic analysis of a cylindrical ring as a unit cell of a complete composite under applied stress in the complex plane using cubic polynomials

NASA Astrophysics Data System (ADS)

Monfared, Vahid

2018-03-01

Elastic analysis is analytically presented to predict the behaviors of the stress and displacement components in the cylindrical ring as a unit cell of a complete composite under applied stress in the complex plane using cubic polynomials. This analysis is based on the complex computation of the stress functions in the complex plane and polar coordinates. Also, suitable boundary conditions are considered and assumed to analyze along with the equilibrium equations and bi-harmonic equation. This method has some important applications in many fields of engineering such as mechanical, civil and material engineering generally. One of the applications of this research work is in composite design and designing the cylindrical devices under various loadings. Finally, it is founded that the convergence and accuracy of the results are suitable and acceptable through comparing the results.

Metastable structure of Li13Si4

NASA Astrophysics Data System (ADS)

Gruber, Thomas; Bahmann, Silvia; Kortus, Jens

2016-04-01

The Li13Si4 phase is one out of several crystalline lithium silicide phases, which is a potential electrode material for lithium ion batteries and contains a high theoretical specific capacity. By means of ab initio methods like density functional theory (DFT) many properties such as heat capacity or heat of formation can be calculated. These properties are based on the calculation of phonon frequencies, which contain information about the thermodynamical stability. The current unit cell of "Li13Si4" given in the ICSD database is unstable with respect to DFT calculations. We propose a modified unit cell that is stable in the calculations. The evolutionary algorithm EVO found a structure very similar to the ICSD one with both of them containing metastable lithium positions. Molecular dynamic simulations show a phase transition between both structures where these metastable lithium atoms move. This phase transition is achieved by a very fast one-dimensional lithium diffusion and stabilizes this phase.

Investigation of Micro-Scale Architectural Effects on Damage of Composites

NASA Technical Reports Server (NTRS)

Stier, Bertram; Bednarcyk, Brett A.; Simon, Jaan W.; Reese, Stefanie

2015-01-01

This paper presents a three-dimensional, energy based, anisotropic, stiffness reduction, progressive damage model for composite materials and composite material constituents. The model has been implemented as a user-defined constitutive model within the Abaqus finite element software package and applied to simulate the nonlinear behavior of a damaging epoxy matrix within a unidirectional composite material. Three different composite microstructures were considered as finite element repeating unit cells, with appropriate periodicity conditions applied at the boundaries. Results representing predicted transverse tensile, longitudinal shear, and transverse shear stress-strain curves are presented, along with plots of the local fields indicating the damage progression within the microstructure. It is demonstrated that the damage model functions appropriately at the matrix scale, enabling localization of the damage to simulate failure of the composite material. The influence of the repeating unit cell geometry and the effect of the directionality of the applied loading are investigated and discussed.

Bottom-up construction of a superstructure in a porous uranium-organic crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Peng; Vermeulen, Nicolaas A.; Malliakas, Christos D.

Bottom-up construction of highly intricate structures from simple building blocks remains one of the most difficult challenges in chemistry. We report a structurally complex, mesoporous uranium-based metal-organic framework (MOF) made from simple starting components. The structure comprises 10 uranium nodes and seven tricarboxylate ligands (both crystallographically nonequivalent), resulting in a 173.3-angstrom cubic unit cell enclosing 816 uranium nodes and 816 organic linkers—the largest unit cell found to date for any nonbiological material. The cuboctahedra organize into pentagonal and hexagonal prismatic secondary structures, which then form tetrahedral and diamond quaternary topologies with unprecedented complexity. This packing results in the formation ofmore » colossal icosidodecahedral and rectified hexakaidecahedral cavities with internal diameters of 5.0 nanometers and 6.2 nanometers, respectively—ultimately giving rise to the lowest-density MOF reported to date.« less

A Comparison Between Jerusalem Cross and Square Patch Frequency Selective Surfaces for Low Profile Antenna Applications

NASA Technical Reports Server (NTRS)

Cure, David; Weller, Thomas; Miranda, Felix A.

2011-01-01

In this paper, a comparison between Jerusalem Cross (JC) and Square Patch (SP) based Frequency Selected Surfaces (FSS) for low profile antenna applications is presented. The comparison is aimed at understanding the performance of low profile antennas backed by high impedance surfaces. In particular, an end loaded planar open sleeve dipole (ELPOSD) antenna is examined due to the various parameters within its configuration, offering significant design flexibility and a wide operating bandwidth. Measured data of the antennas demonstrate that increasing the number of unit cells improves the fractional bandwidth. The antenna bandwidth increased from 0.8% to 1.8% and from 0.8% to 2.7% for the JC and SP structures, respectively. The number of unit cells was increased from 48 to 80 for the JC-FSS and from 24 to 48 for the SP-FSS.

Hydrostatic Compression of 2,4,6,8,10,12 hexanitrohexaaza isowurtzitane (CL20) Co Crystals

DTIC Science & Technology

2016-12-01

crystal with analyses of the unit cell volume, band structure , elastic coefficients, and optical absorption Approved for public release...studied and for each system the high pressure (to 50 GPa) unit cell parameters, bulk modulus, and estimates of the shock, particle, and sound ...List of Figures Fig. 1 Experimental unit cell structures of ε-CL20 and co-crystals. For each structure , the CL20 molecules are red and the guest

A Method to Formulate the Unit Cell for Density Functional Theory (DFT) Calculations of the Electronic Band Structure of Heterostructures of Two-dimensional Nanosheets

DTIC Science & Technology

2015-04-01

distribution is unlimited. i CONTENTS Page Introduction 1 Two-dimensional Material Geometry and Analogs with Close-packed Systems 1 Matching... System Lattice Vectors: An Optimization Problem 1 Generating the System Unit Cell 3 Transition Metal Dichalcogenides (TMDCS) with Mismatched... system being analyzed. The creation of a unit cell that accurately describes the system remains one of the largest challenges for DFT calculations

Self-similar grid patterns in free-space shuffle-exchange networks

NASA Astrophysics Data System (ADS)

Haney, Michael W.

1993-12-01

Self-similar grid patterns are proposed as an alternative to rectangular grid, array optoelectronic sources, and detectors of smart pixels. For shuffle based multistage interconnection networks, it is suggested that smart pixel should not be arrayed on a rectangular grid and that smart pixel unit cell should be the kernel of a self-similar grid pattern.

Solid-state Image Sensor with Focal-plane Digital Photon-counting Pixel Array

NASA Technical Reports Server (NTRS)

Fossum, Eric R.; Pain, Bedabrata

1997-01-01

A solid-state focal-plane imaging system comprises an NxN array of high gain. low-noise unit cells. each unit cell being connected to a different one of photovoltaic detector diodes, one for each unit cell, interspersed in the array for ultra low level image detection and a plurality of digital counters coupled to the outputs of the unit cell by a multiplexer(either a separate counter for each unit cell or a row of N of counters time shared with N rows of digital counters). Each unit cell includes two self-biasing cascode amplifiers in cascade for a high charge-to-voltage conversion gain (greater than 1mV/e(-)) and an electronic switch to reset input capacitance to a reference potential in order to be able to discriminate detection of an incident photon by the photoelectron (e(-))generated in the detector diode at the input of the first cascode amplifier in order to count incident photons individually in a digital counter connected to the output of the second cascade amplifier. Reseting the input capacitance and initiating self-biasing of the amplifiers occurs every clock cycle of an integratng period to enable ultralow light level image detection by the may of photovoltaic detector diodes under such ultralow light level conditions that the photon flux will statistically provide only a single photon at a time incident on anyone detector diode during any clock cycle.

Controlling the Morphology of BDTT-DPP-Based Small Molecules via End-Group Functionalization for Highly Efficient Single and Tandem Organic Photovoltaic Cells.

PubMed

Kim, Ji-Hoon; Park, Jong Baek; Yang, Hoichang; Jung, In Hwan; Yoon, Sung Cheol; Kim, Dongwook; Hwang, Do-Hoon

2015-11-04

A series of narrow-band gap, π-conjugated small molecules based on diketopyrrolopyrrole (DPP) electron acceptor units coupled with alkylthienyl-substituted-benzodithiophene (BDTT) electron donors were designed and synthesized for use as donor materials in solution-processed organic photovoltaic cells. In particular, by end-group functionalization of the small molecules with fluorine derivatives, the nanoscale morphologies of the photoactive layers of the photovoltaic cells were successfully controlled. The influences of different fluorine-based end-groups on the optoelectronic and morphological properties, carrier mobilities, and the photovoltaic performances of these materials were investigated. A high power conversion efficiency (PCE) of 6.00% under simulated solar light (AM 1.5G) illumination has been achieved for organic photovoltaic cells based on a small-molecule bulk heterojunction system consisting of a trifluoromethylbenzene (CF3) end-group-containing oligomer (BDTT-(DPP)2-CF3) as the donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor. As a result, the introduction of CF3 end-groups has been found to enhance both the short circuit current density (JSC) and fill factor (FF). A tandem photovoltaic device comprising an inverted BDTT-(DPP)2-CF3:PC71BM cell and a poly(3-hexylthiophene) (P3HT):indene-C60-bisadduct (IC60BA)-based cell as the top and bottom cell components, respectively, showed a maximum PCE of 8.30%. These results provide valuable guidelines for the rational design of conjugated small molecules for applications in high-performance organic photovoltaic cells. Furthermore, to the best of our knowledge, this is the first report on the design of fluorine-functionalized BDTT-DPP-based small molecules, which have been shown to be a viable candidate for use in inverted tandem cells.

A flexible and portable powerpack by solid-state supercapacitor and dye-sensitized solar cell integration

NASA Astrophysics Data System (ADS)

Scalia, Alberto; Bella, Federico; Lamberti, Andrea; Bianco, Stefano; Gerbaldi, Claudio; Tresso, Elena; Pirri, Candido Fabrizio

2017-08-01

The recent need to benefit from electricity in every moment of daily life, particularly when the access to the electric grid is limited, is forcing the scientific and industrial community to an intensive effort towards the production of integrated energy harvesting and storage devices able to drive low power electronics. In this framework, flexibility represents a mandatory requirement to cover non-planar or bendable surfaces, more and more common in nowadays-electronic devices. To this purpose, here we present an innovative device consisting of a TiO2 nanotube-based dye sensitized solar cell and a graphene-based electrical double layer capacitor integrated in a flexible architecture. Both the units are obtained by easily scalable fabrication processes exploiting photopolymer membranes as electrolytes and metal grids as current collectors. The performance of the two units and of the integrated system are thoroughly investigated by electrochemical measurements also under different irradiation conditions. To the best of our knowledge, this work shows the highest energy conversion and storage efficiency (1.02%) ever attained under 1 Sun irradiation condition for a flexible dye-sensitized-based non-wired photocapacitor. Noteworthy, this value dramatically increases while lowering the illumination condition to 0.3 Sun, achieving a remarkable value of 1.46%, thus showing optimal performances in real operation conditions.

Effect of Ti Doping to Maintain Structural Disorder in InOx-Based Thin-Film Transistors Fabricated by RF Magnetron Sputtering

NASA Astrophysics Data System (ADS)

Aikawa, Shinya

2017-12-01

The effect of Ti doping in an indium oxide (InOx)-based semiconductor is investigated for the thin-film transistor (TFT) property and crystal structure of the film. InOx and Ti-doped InOx (InTiOx) films deposited by RF magnetron sputtering under the same O2 partial pressure conditions were systematically compared. The TFT behavior of the InOx showed higher conductivity than that of the InTiOx and was drastically changed to metallic conduction after annealing at 150 °C. Under the annealing conditions when the electrical transition to the metallic behavior occurred, the InOx film was crystallized. The X-ray diffraction analysis revealed that the shrinkage of the In2O3 unit cell is pronounced in the case of InOx films. Thus, Ti dopants may play the role as a suppressor for shrinkage of the unit cell, i.e. maintaining neighboring In-In distances, in addition to suppression of oxygen vacancies. The In-In distance, which is related to the overlapping of In 5 s orbitals, is considered to be one of the key factor for which InOx-based materials are utilized as conducting films or semiconducting channels.

Development of a high power density 2.5 kW class solid oxide fuel cell stack

NASA Astrophysics Data System (ADS)

Yokoo, M.; Mizuki, K.; Watanabe, K.; Hayashi, K.

2011-10-01

We have developed a 2.5 kW class solid oxide fuel cell stack. It is constructed by combining 70 power generation units, each of which is composed of an anode-supported planar cell and separators. The power generation unit for the 2.5 kW class stack were designed so that the height of the unit were scaled down by 2/3 of that for our conventional 1.5 kW class stack. The power generation unit for the 2.5 kW class stack provided the same output as the unit used for the conventional 1.5 kW class stack, which means that power density per unit volume of the 2.5 kW class stack was 50% greater than that of the conventional 1.5 kW class stack.

Economic viability of thin-film tandem solar modules in the United States

NASA Astrophysics Data System (ADS)

Sofia, Sarah E.; Mailoa, Jonathan P.; Weiss, Dirk N.; Stanbery, Billy J.; Buonassisi, Tonio; Peters, I. Marius

2018-05-01

Tandem solar cells are more efficient but more expensive per unit area than established single-junction (SJ) solar cells. To understand when specific tandem architectures should be utilized, we evaluate the cost-effectiveness of different II-VI-based thin-film tandem solar cells and compare them to the SJ subcells. Levelized cost of electricity (LCOE) and energy yield are calculated for four technologies: industrial cadmium telluride and copper indium gallium selenide, and their hypothetical two-terminal (series-connected subcells) and four-terminal (electrically independent subcells) tandems, assuming record SJ quality subcells. Different climatic conditions and scales (residential and utility scale) are considered. We show that, for US residential systems with current balance-of-system costs, the four-terminal tandem has the lowest LCOE because of its superior energy yield, even though it has the highest US per watt (US W-1) module cost. For utility-scale systems, the lowest LCOE architecture is the cadmium telluride single junction, the lowest US W-1 module. The two-terminal tandem requires decreased subcell absorber costs to reach competitiveness over the four-terminal one.

Chlor-alkali producers evaluate safer alternatives to asbestos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stadig, W.

Until recently, 75% of all US capacity for producing chlor-alkali - more than 40% of the world's capacity - has used asbestos diaphragm-cell technology. Although the Environmental Protection Agency continues to exempt asbestos use in diaphragms from restrictions, producers are considering alternatives. In Germany, stringent regulations will ban asbestos in chlor-alkali production after 1994. Heavy fines were levied recently against some chlor-alkali producers in the United States when EPA inspectors found asbestos fibers in cell renewal areas. Restrictions on the mining of asbestos raise the cost of obtaining adequate amounts of high-quality asbestos and gradually raise the cost of transportingmore » and discarding spent diaphragms. Two alternatives are to use newly developed, non-asbestos diaphragms or to convert to existing ion-exchange membrane-cell technology. Only the former seems economical in the United States. The non-asbestos diaphragm is based on an inorganic polymer composite developed in 1988 as an asbestos substitute. The composite received Du Pont's Plunkett Award for Innovation with Teflon[trademark], landed on the National Development Association's 1991 Honor Roll and became a 1991 R D 100 Award winner. 6 figs.« less

Fundamental results from microgravity cell experiments with possible commericial applications

NASA Technical Reports Server (NTRS)

Winget, Charles M.; Fast, Thomas N.; Hinds, Williams E.; Schaefer, R. L.; Callahan, Paul X.

1989-01-01

Some of the major milestones are presented for studies in cell biology that were conducted by the Soviet Union and the United States in the upper layers of the atmosphere and in outer space for more than thirty-five years. The goals have changed as new knowledge is acquired and the priorities for the use of microgravity have shifted toward basic research and commercial applications. Certain details concerning the impact of microgravity on cell systems is presented. However, it needs to be emphasized that in planning and conducting microgravity experiments, there are some important prerequisites not normally taken into account. Apart from the required background knowledge of previous microgravity and ground-based experiments, the investigator should have the understanding of the hardware as a physical unit, the complete knowledge of its operation, the range of its capabilities and the anticipation of problems that may occur. Moreover, if the production of commercial products in space is to be manifested, data obtained from previous microgravity experiments must be used to optimize the design of flight hardware.

Donating embryos to stem cell research.

PubMed

Scully, Jackie Leach; Haimes, Erica; Mitzkat, Anika; Porz, Rouven; Rehmann-Sutter, Christoph

2012-03-01

This paper is based on linked qualitative studies of the donation of human embryos to stem cell research carried out in the United Kingdom, Switzerland, and China. All three studies used semi-structured interview protocols to allow an in-depth examination of donors' and non-donors' rationales for their donation decisions, with the aim of gaining information on contextual and other factors that play a role in donor decisions and identifying how these relate to factors that are more usually included in evaluations made by theoretical ethics. Our findings have implications for one factor that has previously been suggested as being of ethical concern: the role of gratitude. Our empirical work shows no evidence that interpersonal gratitude is an important factor, but it does support the existence of a solidarity-based desire to "give something back" to medical research. Thus, we use empirical data to expand and refine the conceptual basis of bioethically theorizing the IVF-stem cell interface.

Mesenchymal progenitor cells for the osteogenic lineage.

PubMed

Ono, Noriaki; Kronenberg, Henry M

2015-09-01

Mesenchymal progenitors of the osteogenic lineage provide the flexibility for bone to grow, maintain its function and homeostasis. Traditionally, colony-forming-unit fibroblasts (CFU-Fs) have been regarded as surrogates for mesenchymal progenitors; however, this definition cannot address the function of these progenitors in their native setting. Transgenic murine models including lineage-tracing technologies based on the cre-lox system have proven to be useful in delineating mesenchymal progenitors in their native environment. Although heterogeneity of cell populations of interest marked by a promoter-based approach complicates overall interpretation, an emerging complexity of mesenchymal progenitors has been revealed. Current literatures suggest two distinct types of bone progenitor cells; growth-associated mesenchymal progenitors contribute to explosive growth of bone in early life, whereas bone marrow mesenchymal progenitors contribute to the much slower remodeling process and response to injury that occurs mainly in adulthood. More detailed relationships of these progenitors need to be studied through further experimentation.

State participation in the creation of fuel-cell-based power plants to meet civilian demand in Russia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pekhota, F.N.

1996-04-01

At present, up to 70% of Russian territory is not covered by central electrical distribution systems. In the field of fuel cell power plants, Russia is at parity with the leading foreign countries with respect to both technical and economic performance and the level of research being conducted. Civilian use of these generating systems on a broad scale, however, demands that a number of problems be solved, particularly those relating to the need for longer plant service life, lower unit cost of electricity, etc. The Ministry of Science and technical Policy of the Russian Federation issued a decree creating amore » new are of concentration, `Fuel Cell Based Power Plants for Civilian Needs,` in the GNTPR `Environmentally Clean Power Industry,` which will form the basis for financial support in this area out of the federal budget.« less

PyMUS: Python-Based Simulation Software for Virtual Experiments on Motor Unit System

PubMed Central

Kim, Hojeong; Kim, Minjung

2018-01-01

We constructed a physiologically plausible computationally efficient model of a motor unit and developed simulation software that allows for integrative investigations of the input–output processing in the motor unit system. The model motor unit was first built by coupling the motoneuron model and muscle unit model to a simplified axon model. To build the motoneuron model, we used a recently reported two-compartment modeling approach that accurately captures the key cell-type-related electrical properties under both passive conditions (somatic input resistance, membrane time constant, and signal attenuation properties between the soma and the dendrites) and active conditions (rheobase current and afterhyperpolarization duration at the soma and plateau behavior at the dendrites). To construct the muscle unit, we used a recently developed muscle modeling approach that reflects the experimentally identified dependencies of muscle activation dynamics on isometric, isokinetic and dynamic variation in muscle length over a full range of stimulation frequencies. Then, we designed the simulation software based on the object-oriented programing paradigm and developed the software using open-source Python language to be fully operational using graphical user interfaces. Using the developed software, separate simulations could be performed for a single motoneuron, muscle unit and motor unit under a wide range of experimental input protocols, and a hierarchical analysis could be performed from a single channel to the entire system behavior. Our model motor unit and simulation software may represent efficient tools not only for researchers studying the neural control of force production from a cellular perspective but also for instructors and students in motor physiology classroom settings. PMID:29695959

PyMUS: Python-Based Simulation Software for Virtual Experiments on Motor Unit System.

PubMed

Kim, Hojeong; Kim, Minjung

2018-01-01

We constructed a physiologically plausible computationally efficient model of a motor unit and developed simulation software that allows for integrative investigations of the input-output processing in the motor unit system. The model motor unit was first built by coupling the motoneuron model and muscle unit model to a simplified axon model. To build the motoneuron model, we used a recently reported two-compartment modeling approach that accurately captures the key cell-type-related electrical properties under both passive conditions (somatic input resistance, membrane time constant, and signal attenuation properties between the soma and the dendrites) and active conditions (rheobase current and afterhyperpolarization duration at the soma and plateau behavior at the dendrites). To construct the muscle unit, we used a recently developed muscle modeling approach that reflects the experimentally identified dependencies of muscle activation dynamics on isometric, isokinetic and dynamic variation in muscle length over a full range of stimulation frequencies. Then, we designed the simulation software based on the object-oriented programing paradigm and developed the software using open-source Python language to be fully operational using graphical user interfaces. Using the developed software, separate simulations could be performed for a single motoneuron, muscle unit and motor unit under a wide range of experimental input protocols, and a hierarchical analysis could be performed from a single channel to the entire system behavior. Our model motor unit and simulation software may represent efficient tools not only for researchers studying the neural control of force production from a cellular perspective but also for instructors and students in motor physiology classroom settings.

Beyond the Niche: Tissue-Level Coordination of Stem Cell Dynamics

PubMed Central

O’Brien, Lucy Erin; Bilder, David

2014-01-01

Adult animals rely on populations of stem cells to ensure organ function throughout their lifetime. Stem cells are governed by signals from stem cell niches, and much is known about how single niches promote stemness and direct stem cell behavior. However, most organs contain a multitude of stem cell–niche units, which are often distributed across the entire expanse of the tissue. Beyond the biology of individual stem cell–niche interactions, the next challenge is to uncover the tissue-level processes that orchestrate spatial control of stem-based renewal, repair, and remodeling throughout a whole organ. Here we examine what is known about higher order mechanisms for interniche coordination in epithelial organs, whose simple geometry offers a promising entry point for understanding the regulation of niche number, distribution, and activity. We also consider the potential existence of stem cell territories and how tissue architecture may influence niche coordination. PMID:23937350

Synthesizing Biomolecule-based Boolean Logic Gates

PubMed Central

Miyamoto, Takafumi; Razavi, Shiva; DeRose, Robert; Inoue, Takanari

2012-01-01

One fascinating recent avenue of study in the field of synthetic biology is the creation of biomolecule-based computers. The main components of a computing device consist of an arithmetic logic unit, the control unit, memory, and the input and output devices. Boolean logic gates are at the core of the operational machinery of these parts, hence to make biocomputers a reality, biomolecular logic gates become a necessity. Indeed, with the advent of more sophisticated biological tools, both nucleic acid- and protein-based logic systems have been generated. These devices function in the context of either test tubes or living cells and yield highly specific outputs given a set of inputs. In this review, we discuss various types of biomolecular logic gates that have been synthesized, with particular emphasis on recent developments that promise increased complexity of logic gate circuitry, improved computational speed, and potential clinical applications. PMID:23526588

Synthesizing biomolecule-based Boolean logic gates.

PubMed

Miyamoto, Takafumi; Razavi, Shiva; DeRose, Robert; Inoue, Takanari

2013-02-15

One fascinating recent avenue of study in the field of synthetic biology is the creation of biomolecule-based computers. The main components of a computing device consist of an arithmetic logic unit, the control unit, memory, and the input and output devices. Boolean logic gates are at the core of the operational machinery of these parts, and hence to make biocomputers a reality, biomolecular logic gates become a necessity. Indeed, with the advent of more sophisticated biological tools, both nucleic acid- and protein-based logic systems have been generated. These devices function in the context of either test tubes or living cells and yield highly specific outputs given a set of inputs. In this review, we discuss various types of biomolecular logic gates that have been synthesized, with particular emphasis on recent developments that promise increased complexity of logic gate circuitry, improved computational speed, and potential clinical applications.

Analysis of the Spanish CCR5-∆32 inventory of cord blood units: lower cell counts in homozygous donors.

PubMed

Enrich, Emma; Vidal, Francisco; Sánchez-Gordo, Francisco; Gómez-Zumaquero, Juan M; Balas, Antonio; Rudilla, Francesc; Barea, Luisa; Castro, Ana; Larrea, Luis; Perez-Vaquero, Miguel A; Prat, Isidro; Querol, Sergio; Garrido, Gregorio; Matesanz, Rafael; Carreras, Enric; Duarte, Rafael F

2018-02-06

The possibility to use CCR5-∆32 umbilical cord blood to cure HIV infection in patients in need of a hematopoietic transplant has been suggested. The less stringent HLA compatibility needed in this type of transplant facilitates the search of a suitable donor having the CCR5-∆32 mutation. To achieve an inventory of CCR5-∆32 cord blood units, the 20,236 best cell quality units of the Spanish Registry were genotyped. Furthermore, their CD34 + and total nucleated cells counts, blood type, gender, HLA and donor's geographical and ancestral origin were analyzed. The results showed 130 (0.64%) units homozygous for the deletion, 2,646 (13.08%) heterozygous and 17,460 (86.28%) did not present the mutation. Interestingly, a significant lower amount of CD34 + cells was found in the CCR5-∆32 homozygous units. In addition, a significant association was found among donor's ancestral origin and the mutation, with a higher percentage of CCR5-∆32 units with a European ancestry. In summary, identification of a relatively high number of CCR5-∆32 units is feasible and will facilitate the development of clinical trials for HIV cure in patients requiring hematopoietic transplantation. Further studies are required to understand the significance of lower cell counts within the CCR5-∆32 homozygous group and its clinical impact.

A mitotically inheritable unit containing a MAP kinase module

PubMed Central

Kicka, Sébastien; Bonnet, Crystel; Sobering, Andrew K.; Ganesan, Latha P.; Silar, Philippe

2006-01-01

Prions are novel kinds of hereditary units, relying solely on proteins, that are infectious and inherited in a non-Mendelian fashion. To date, they are either based on autocatalytic modification of a 3D conformation or on autocatalytic cleavage. Here, we provide further evidence that in the filamentous fungus Podospora anserina, a MAP kinase cascade is probably able to self-activate and generate C, a hereditary unit that bears many similarities to prions and triggers cell degeneration. We show that in addition to the MAPKKK gene, both the MAPKK and MAPK genes are necessary for the propagation of C, and that overexpression of MAPK as that of MAPKKK facilitates the appearance of C. We also show that a correlation exists between the presence of C and localization of the MAPK inside nuclei. These data emphasize the resemblance between prions and a self-positively regulated cascade in terms of their transmission. This thus further expands the concept of protein-base inheritance to regulatory networks that have the ability to self-activate. PMID:16938837

A mitotically inheritable unit containing a MAP kinase module.

PubMed

Kicka, Sébastien; Bonnet, Crystel; Sobering, Andrew K; Ganesan, Latha P; Silar, Philippe

2006-09-05

Prions are novel kinds of hereditary units, relying solely on proteins, that are infectious and inherited in a non-Mendelian fashion. To date, they are either based on autocatalytic modification of a 3D conformation or on autocatalytic cleavage. Here, we provide further evidence that in the filamentous fungus Podospora anserina, a MAP kinase cascade is probably able to self-activate and generate C, a hereditary unit that bears many similarities to prions and triggers cell degeneration. We show that in addition to the MAPKKK gene, both the MAPKK and MAPK genes are necessary for the propagation of C, and that overexpression of MAPK as that of MAPKKK facilitates the appearance of C. We also show that a correlation exists between the presence of C and localization of the MAPK inside nuclei. These data emphasize the resemblance between prions and a self-positively regulated cascade in terms of their transmission. This thus further expands the concept of protein-base inheritance to regulatory networks that have the ability to self-activate.

Analytical resource assessment method for continuous (unconventional) oil and gas accumulations - The "ACCESS" Method

USGS Publications Warehouse

Crovelli, Robert A.; revised by Charpentier, Ronald R.

2012-01-01

The U.S. Geological Survey (USGS) periodically assesses petroleum resources of areas within the United States and the world. The purpose of this report is to explain the development of an analytic probabilistic method and spreadsheet software system called Analytic Cell-Based Continuous Energy Spreadsheet System (ACCESS). The ACCESS method is based upon mathematical equations derived from probability theory. The ACCESS spreadsheet can be used to calculate estimates of the undeveloped oil, gas, and NGL (natural gas liquids) resources in a continuous-type assessment unit. An assessment unit is a mappable volume of rock in a total petroleum system. In this report, the geologic assessment model is defined first, the analytic probabilistic method is described second, and the spreadsheet ACCESS is described third. In this revised version of Open-File Report 00-044 , the text has been updated to reflect modifications that were made to the ACCESS program. Two versions of the program are added as appendixes.

A mathematical model for the iron/chromium redox battery

NASA Technical Reports Server (NTRS)

Fedkiw, P. S.; Watts, R. W.

1984-01-01

A mathematical model has been developed to describe the isothermal operation of a single anode-separator-cathode unit cell in a redox-flow battery and has been applied to the NASA iron/chromium system. The model, based on porous electrode theory, incorporates redox kinetics, mass transfer, and ohmic effects as well as the parasitic hydrogen reaction which occurs in the chromium electrode. A numerical parameter study was carried out to predict cell performance to aid in the rational design, scale-up, and operation of the flow battery. The calculations demonstrate: (1) an optimum electrode thickness and electrolyte flow rate exist; (2) the amount of hydrogen evolved and, hence, cycle faradaic efficiency, can be affected by cell geometry, flow rate, and charging procedure; (3) countercurrent flow results in enhanced cell performance over cocurrent flow; and (4) elevated temperature operation enhances cell performance.

Demonstration of a residential CHP system based on PEM fuel cells

NASA Astrophysics Data System (ADS)

Gigliucci, G.; Petruzzi, L.; Cerelli, E.; Garzisi, A.; La Mendola, A.

Fuel cell-based CHP systems are very attractive for stationary energy generation, since they allow production of electricity and heat in a decentralised, quiet, efficient and environmentally friendly way. As a means of evaluating this new technology, Enel Produzione installed a beta-version fuel cell CHP system, supplied by H-Power, at its experimental area sited in Livorno (Italy), and submitted it to a series of tests. The system is a co-generative unit, converting natural gas into electricity and heat: the former is delivered to local loads using electric load following capability; the latter is delivered to the experimental area hydraulic refrigeration circuit. Experiments were aimed at assessing the suitability of this kind of system to supply Italian residential customers. Factors such as performances, flexibility and operational requirements were evaluated under all the possible operating conditions, both under grid connected and stand alone configurations. At the same time, a mathematical model of the FC/CHP unit was developed to allow for the prediction of system performances and operating parameters under off-design conditions. This model can be used as an effective tool to optimise system operation when a particular customer has to be supplied. Results show that the prototype behaved as expected by a first "proof of concept" system and outline improvements to be achieved in order to satisfy the energy needs of small residential applications.

Multi-stability and variable stiffness of cellular solids designed based on origami patterns

NASA Astrophysics Data System (ADS)

Sengupta, Sattam; Li, Suyi

2017-04-01

The application of origami-inspired designs to engineered structures and materials has been a subject of much research efforts. These structures and materials, whose mechanical properties are directly related to the geometry of folding, are capable of achieving a host of unique adaptive functions. In this study, we investigate a three-dimensional multistability and variable stiffness function of a cellular solid based on the Miura-Ori folding pattern. The unit cell of such a solid, consisting of two stacked Miura-Ori sheets, can be elastically bistable due to the nonlinear relationship between rigid-folding deformation and crease material bending. Such a bistability possesses an unorthodox property: the critical, unstable configuration lies on the same side of two stable ones, so that two different force-deformation curves co-exist within the same range of deformation. By exploiting such unique stability properties, we can achieve a programmable stiffness change between the two elastically stable states, and the stiffness differences can be prescribed by tailoring the crease patterns of the cell. This paper presents a comprehensive parametric study revealing the correlations between such variable stiffness and various design parameters. The unique properties stemming from the bistability and design of such a unit cell can be advanced further by assembling them into a solid which can be capable of shape morphing and programmable mechanical properties.

Crystal-Chemical Correlations in Chromites from Kimberlitic and Non-Kimberlitic Sources.

NASA Astrophysics Data System (ADS)

Freckelton, C. N.; Flemming, R. L.

2009-05-01

This study explores the utility of micro X-ray diffraction (μXRD) as a tool for diamond exploration, as a compliment to current industry-standard techniques such as electron probe microanalysis (EPMA). Here we examine chromite. As one of the first phases to crystallize in mantle rocks, it is a useful indicator of upper mantle magmatic conditions in rocks that have been sampled by kimberlites. In addition, chromite does not alter easily from chemical and physical weathering processes. As such, chromite is a useful kimberlite indicator mineral in diamond exploration. We present correlations between crystal structure (unit cell) and chemical composition of chromite, (Fe,Mg)[Cr, Al]2O4, using correlated μXRD and EPMA data for 133 chromites from a three source locations: Two kimberlite sources and one non-kimberlitic source from an Archean granite/greenstone terrain. Quantitative analysis was performed using Electron Probe Microanalysis (EPMA) at Mineral Services, South Africa, prior to the loan of the samples. Randomly-oriented chromite grains, approximately 500 μm in diameter, were analyzed as previously mounted for EPMA. Micro X-ray-diffraction was performed using a Bruker D8-Discover Diffractometer, with θ-θ geometry, with CuKα radiation, operating at 40 kV and 40 mA, with nominal beam diameter of 500 μm. The data were collected in omega scan mode. Two dimensional General Area Detector Diffraction System (GADDS) images were collected for 20 minutes per image, and integrated to produce one-dimensional plots of intensity versus 2θ, for subsequent unit cell refinement using CELREF. Although all samples in this study were considered to be 'chromite', a plot of Cr/(Cr+Al) versus Fe2+/(Fe2++Mg) shows extensive substitution among four dominant members: chromite (FeCr2O4), magnesio-chromite (MgCr2O4), spinel (MgAl2O4), and hercynite (FeAl2O4), where Mg and Fe2+ substitute for one another on the tetrahedral site, and Cr and Al substitute for one another on the octahedral site. Our data are widely variable as compared to the field occupied by chromite inclusions in diamonds (high Cr and Mg (˜60 wt %) and very low Ti (˜0.40 wt %). Plots of the unit cell parameter, ao, versus composition demonstrate a decrease in unit cell size with increasing Al content (and corresponding decrease in Cr content), consistent with a smaller cation radius for Al versus Cr (Al=0.675 Å and Cr=0.905 Å). The trend in unit cell size is unlikely to be effected by Mg-Fe substitution because of the very small difference in their tetrahedral cation radii (Fe2+=0.835 Å and Mg=0.86 Å). Initial plots of composition versus unit cell parameter were clearly able to distinguish a difference between unit cell of kimberlitic chromites and non-kimberlitic chromites. The significantly higher Cr content in kimberlitic chromites (radius=0.905 Å), and correspondingly higher Al content in non-kimberlitic chromites (radius=0.675 Å), results in a striking bimodal distribution in unit cell parameter, ao, where kimberlitic chromites have a larger unit cell (> 8.3 Å) than non-kimberlitic chromites (< 8.3 Å). This preliminary data provides a useful starting point for screening minerals from naturally relevant chromite solid solutions using their corresponding unit cell parameters. Future work will examine which site substitutions (octahedral versus tetrahedral) are affecting the unit cell as well as the effect of cation order-disorder on unit cell parameters.

Large-scale progenitor cell expansion for multiple donors in a monitored hollow fibre bioreactor.

PubMed

Lambrechts, Toon; Papantoniou, Ioannis; Rice, Brent; Schrooten, Jan; Luyten, Frank P; Aerts, Jean-Marie

2016-09-01

With the increasing scale in stem cell production, a robust and controlled cell expansion process becomes essential for the clinical application of cell-based therapies. The objective of this work was the assessment of a hollow fiber bioreactor (Quantum Cell Expansion System from Terumo BCT) as a cell production unit for the clinical-scale production of human periosteum derived stem cells (hPDCs). We aimed to demonstrate comparability of bioreactor production to standard culture flask production based on a product characterization in line with the International Society of Cell Therapy in vitro benchmarks and supplemented with a compelling quantitative in vivo bone-forming potency assay. Multiple process read-outs were implemented to track process performance and deal with donor-to-donor-related variation in nutrient needs and harvest timing. The data show that the hollow fiber bioreactor is capable of robustly expanding autologous hPDCs on a clinical scale (yield between 316 million and 444 million cells starting from 20 million after ± 8 days of culture) while maintaining their in vitro quality attributes compared with the standard flask-based culture. The in vivo bone-forming assay on average resulted in 10.3 ± 3.7% and 11.0 ± 3.8% newly formed bone for the bioreactor and standard culture flask respectively. The analysis showed that the Quantum system provides a reproducible cell expansion process in terms of yields and culture conditions for multiple donors. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Cell-based interventions for neurologic conditions: ethical challenges for early human trials.

PubMed

Mathews, D J H; Sugarman, J; Bok, H; Blass, D M; Coyle, J T; Duggan, P; Finkel, J; Greely, H T; Hillis, A; Hoke, A; Johnson, R; Johnston, M; Kahn, J; Kerr, D; Kurtzberg, J; Liao, S M; McDonald, J W; McKhann, G; Nelson, K B; Rao, M; Regenberg, A; Siegel, A W; Smith, K; Solter, D; Song, H; Vescovi, A; Young, W; Gearhart, J D; Faden, R

2008-07-22

Attempts to translate basic stem cell research into treatments for neurologic diseases and injury are well under way. With a clinical trial for one such treatment approved and in progress in the United States, and additional proposals under review, we must begin to address the ethical issues raised by such early forays into human clinical trials for cell-based interventions for neurologic conditions. An interdisciplinary working group composed of experts in neuroscience, cell biology, bioethics, law, and transplantation, along with leading disease researchers, was convened twice over 2 years to identify and deliberate on the scientific and ethical issues raised by the transition from preclinical to clinical research of cell-based interventions for neurologic conditions. While the relevant ethical issues are in many respects standard challenges of human subjects research, they are heightened in complexity by the novelty of the science, the focus on the CNS, and the political climate in which the science is proceeding. Distinctive challenges confronting US scientists, administrators, institutional review boards, stem cell research oversight committees, and others who will need to make decisions about work involving stem cells and their derivatives and evaluate the ethics of early human trials include evaluating the risks, safety, and benefits of these trials, determining and evaluating cell line provenance, and determining inclusion criteria, informed consent, and the ethics of conducting early human trials in the public spotlight. Further study and deliberation by stakeholders is required to move toward professional and institutional policies and practices governing this research.

Enhancement of toxicity of saporin-based toxins by Gypsophila saponins--kinetic of the saponin.

PubMed

Weng, Alexander; Görick, Cornelia; Melzig, Matthias F

2009-08-01

Saponins are amphiphilic substances consisting of a hydrophobic backbone with one or two hydrophilic sugar units. Recently it was shown that saponinum album (SA) from Gypsophila paniculata L. enhanced cytotoxicity of a saporin-based chimeric toxin (up to 385,000-fold) as well as the toxicity of saporin (up to 100,000-fold) with N-glycosidase activity. Previously we have shown that toxicity of other N-glycosidases such as ricin A-chain, nigrin b, and toxins such as diphtheria toxin or microcystin-LR was not enhanced by SA. This points to a specific SA-dependent mechanism of toxicity enhancement on saporin and saporin-based toxins. Although the cytotoxicity enhancing effect was observed in up to 10 different cell lines, nothing is known about the kinetic of SA under cell culture conditions. Therefore SA was titrated, and the uptake respective liberation profile of SA was investigated in ECV-304 cells. Treatment of cells with [(3)H]-SA leads to an immediate uptake of saponin molecules. After cells were saturated with [(3)H]-SA, a first equilibrium (first eq.) was reached. The first eq. was disturbed by washing until a second equilibrium was reached between the activity observed within cells and that seen in the supernatant. After a further extensive washing, a small portion of saponin molecules remained durable associated with the cell. This portion was sufficient to induce a drastic toxicity enhancement on saporin indicating a long-lasting sensitization of cells against the toxin.

ExTzBox: A Glowing Cyclophane for Live-Cell Imaging.

PubMed

Roy, Indranil; Bobbala, Sharan; Zhou, Jiawang; Nguyen, Minh T; Nalluri, Siva Krishna Mohan; Wu, Yilei; Ferris, Daniel P; Scott, Evan Alexander; Wasielewski, Michael R; Stoddart, J Fraser

2018-06-13

The ideal fluorescent probe for live-cell imaging is bright and non-cytotoxic and can be delivered easily into the living cells in an efficient manner. The design of synthetic fluorophores having all three of these properties, however, has proved to be challenging. Here, we introduce a simple, yet effective, strategy based on well-established chemistry for designing a new class of fluorescent probes for live-cell imaging. A box-like hybrid cyclophane, namely ExTzBox·4X (6·4X, X = PF 6 - , Cl - ), has been synthesized by connecting an extended viologen (ExBIPY) and a dipyridyl thiazolothiazole (TzBIPY) unit in an end-to-end fashion with two p-xylylene linkers. Photophysical studies show that 6·4Cl has a quantum yield Φ F = 1.00. Furthermore, unlike its ExBIPY 2+ and TzBIPY 2+ building units, 6·4Cl is non-cytotoxic to RAW 264.7 macrophages, even with a loading concentration as high as 100 μM, presumably on account of its rigid box-like structure which prevents its intercalation into DNA and may inhibit other interactions with it. After gaining an understanding of the toxicity profile of 6·4Cl, we employed it in live-cell imaging. Confocal microscopy has demonstrated that 6 4+ is taken up by the RAW 264.7 macrophages, allowing the cells to glow brightly with blue laser excitation, without any hint of photobleaching or disruption of normal cell behavior under the imaging conditions. By contrast, the acyclic reference compound Me 2 TzBIPY·2Cl (4·2Cl) shows very little fluorescence inside the cells, which is quenched completely under the same imaging conditions. In vitro cell investigations underscore the significance of using highly fluorescent box-like rigid cyclophanes for live-cell imaging.

Thermodynamic analysis of biofuels as fuels for high temperature fuel cells

NASA Astrophysics Data System (ADS)

Milewski, Jarosław; Bujalski, Wojciech; Lewandowski, Janusz

2011-11-01

Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.

Thermodynamic analysis of biofuels as fuels for high temperature fuel cells

NASA Astrophysics Data System (ADS)

Milewski, Jarosław; Bujalski, Wojciech; Lewandowski, Janusz

2013-02-01

Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.