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At least 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Photoacoustic flow cytometry for nanomaterial research

Conventional flow cytometry is a versatile tool for drug research and cell characterization. However, it is poorly suited for quantification of non-fluorescent proteins and artificial nanomaterials without the use of additional labeling. The rapid growth of biomedical applications for small non-fluorescent nanoparticles (NPs) for drug delivery, image contrast and therapy enhancement, as well as research focused on natural cell pigments and chromophores, demands high-throughput quantification methods for the non-fluorescent components. In this work, we present an advanced novel photoacoustic (PA) fluorescence flow cytometry (PAFFC) platform that integrates NP quantification though PA detection with conventional sample characterization using fluorescence labeling. PAFFC simplifies high-throughput analysis of cell-NP interactions, optimization of targeted nanodrugs, and NP toxicity assessment by providing a direct correlation between NP uptake and characterization of toxicity markers for every cell.

Acoustics↗
NASA NTRS2004

Chromosome aberrations of clonal origin are present in astronauts' blood lymphocytes

Radiation-induced chromosome translocations remain in peripheral blood cells over many years, and can potentially be used to measure retrospective doses or prolonged low-dose rate exposures. However, several recent studies have indicated that some individuals possess clones of cells with balanced chromosome abnormalities, which can result in an overestimation of damage and, therefore, influence the accuracy of dose calculations. We carefully examined the patterns of chromosome damage found in the blood lymphocytes of twelve astronauts, and also applied statistical methods to screen for the presence of potential clones. Cells with clonal aberrations were identified in three of the twelve individuals. These clonal cells were present in samples collected both before and after space flight, and yields are higher than previously reported for healthy individuals in this age range (40-52 years of age). The frequency of clonal damage appears to be even greater in chromosomes prematurely condensed in interphase, when compared with equivalent analysis in metaphase cells. The individuals with clonal aberrations were followed-up over several months and the yields of all clones decreased during this period. Since clonal aberrations may be associated with increased risk of tumorigenesis, it is important to accurately identify cells containing clonal rearrangements for risk assessment as well as biodosimetry. Copyright 2003 S. Karger AG, Basel.

Chromosomes, Human/radiation effects/ultrastructur↗
NASA NTRS2009

Analysis of Chromosomal Aberrations after Low and High Dose Rate Gamma Irradiation in ATM or NBS Suppressed Human Fibroblast Cells

A detailed understanding of the biological effects of heavy nuclei is needed for space radiation protection and for cancer therapy. High-LET radiation produces more complex DNA lesions that may be non-repairable or that may require additional processing steps compared to endogenous DSBs, increasing the possibility of misrepair. Interplay between radiation sensitivity, dose, and radiation quality has not been studied extensively. Previously we studied chromosome aberrations induced by low- and high- LET radiation in several cell lines deficient in ATM (ataxia telangactasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. We found that the yields of both simple and complex chromosomal aberrations were significantly increased in the DSB repair defective cells compared to normal cells. The increased aberrations observed for the ATM and NBS defective lines was due to a significantly larger quadratic dose-response term compared to normal fibroblasts for both simple and complex aberrations, while the linear dose-response term was significantly higher in NBS cells only for simple exchanges. These results point to the importance of the functions of ATM and NBS in chromatin modifications that function to facilitate correct DSB repair and minimize aberration formation. To further understand the sensitivity differences that were observed in ATM and NBS deficient cells, in this study, chromosomal aberration analysis was performed in normal lung fibroblast cells treated with KU-55933, a specific ATM kinase inhibitor, or Mirin, an MRN complex inhibitor involved in activation of ATM. We are also testing siRNA knockdown of these proteins. Normal and ATM or NBS suppressed cells were irradiated with gamma-rays and chromosomes were collected with a premature chromosome condensation (PCC) technique at the first mitosis post-irradiation. Chromosomes were analyzed using a multicolor fluorescence in-situ hybridization (mFISH) chromosome painting method. Preliminary analysis showed that chromosomal exchanges were increased in the cells treated with the specific ATM inhibitor. Possible cytogenetic signatures of acute and low dose-rate gamma irradiation in ATM or Nibrin deficient and suppressed cells will be discussed.

Hada, M.↗
DOE OSTI2013

Materials Analysis of CED Nb Films Being Coated on Bulk Nb Single Cell SRF Cavities

This study is an on-going research on depositing a Nb film on the internal wall of bulk Nb single cell SRF cavities, via a cathodic arc Nb plasma ions source, an coaxial energetic condensation (CED) facility at AASC company. The motivation is to firstly create a homoepitaxy-like Nb/Nb film in a scale of a ~1.5GHz RF single cell cavity. Next, through SRF measurement and materials analysis, it might reveal the baseline properties of the CED-type homoepitaxy Nb films. Literally, a top-surface layer of Nb films which sustains SRF function, always grows up in homo-epitaxy mode, on top of a Nb nucleation layer. Homo-epitaxy growth of Nb must be the final stage (a crystal thickening process) of any coatings of Nb film on alternative cavity structure materials. Such knowledge of Nb-Nb homo-epitaxy is useful to create future realistic SRF cavity film coatings, such as hetero-epitaxy Nb/Cu Films, or template-layer-mitigated Nb films. One large-grain, and three fine grain bulk Nb cavities were coated. They went through cryogenic RF measurement. Preliminary results show that the Q0 of a Nb film could be as same as the pre-coated bulk Nb surface (which received a chemically-buffered polishing plus a light electro-polishing); but quality factor of two tested cavities dropped quickly. We are investigating if the severe Q-slope is caused by hydrogen incorporation before deposition, or is determined by some structural defects during Nb film growth.

Zhao, Xin↗
DOE OSTI2016

Elevated temperature increases carbon and nitrogen fluxes between phytoplankton and heterotrophic bacteria through physical attachment

Quantifying the contribution of marine microorganisms to carbon and nitrogen cycles and their response to predicted ocean warming is one of the main challenges of microbial oceanography. Here we present a single-cell NanoSIMS isotope analysis to quantify C and N uptake by free-living and attached phytoplankton and heterotrophic bacteria, and their response to short-term experimental warming of 4 °C. Elevated temperature increased total C fixation by over 50%, a small but significant fraction of which was transferred to heterotrophs within 12 h. Cell-to-cell attachment doubled the secondary C uptake by heterotrophic bacteria and increased secondary N incorporation by autotrophs by 68%. Warming also increased the abundance of phytoplankton with attached heterotrophs by 80%, and promoted C transfer from phytoplankton to bacteria by 17% and N transfer from bacteria to phytoplankton by 50%. Lastly, our results indicate that phytoplankton-bacteria attachment provides an ecological advantage for nutrient incorporation, suggesting a mutualistic relationship that appears to be enhanced by temperature increases.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Cell dark current–voltage from non-calibrated module electroluminescence image analysis

Here, we present a fast, accurate, and reliable method of obtaining cell dark current–voltage (I–V) curves from module electroluminescence (EL) images without requiring calibration or correction. For a pristine module, EL-derived dark I–V are compared to directly probed data for a variety of changing imaging parameters: camera sensor, lens, filter, aperture width, exposure time (level of sensor saturation), number of images used, and various combinations of these. Pristine modules and those experiencing different modes and degrees of degradation are examined. A recent study of modules using five different cell technologies demonstrates the practicality of our “EL sweep” technique for performance and degradation studies.

14 SOLAR ENERGY↗
DOE OSTI2021

Depowering of Batteries to Reduce Cost of Ownership

(1) Executive Summary: End of life batteries (EOLBs) present a cost and safety liability for their owners and stakeholders. This is due flammability, energy, and power with EOLBs. Current approaches include cumbersome, expensive packaging, specialized shipping, regulated storage, and they are responsible for over half of the cost of recycling. They all expensively and inadequately address symptoms. OnTo has developed and proven a simple way to resolve the problem systemically, through depowering of lithium-ion batteries (and most any battery other than lead). The low-cost process removes flammability, power, and energy in EOLBs through non-toxic chemical processing. The opportunity for commerce of inert scrap is at least $5 billion greater than the commerce in hazardous scrap, all made possible through OnTo’s technology for efficiency and safety. (2) Depowering Improves Safety and Decreases Cost of Battery Ownership: OnTo’s depowering technology will remove half of the cost of EOLB management and recycling. Without this technology, EOLB recycling will always be a liability. EOLB is hazardous due to inherent flammability of electrolyte and lithium. The shipping and commerce of EOLBs is costly and dangerous all along the chain of custody from owner, dealership/shop, shipper, second-life sorter, (shipper again), and finally to the destination facility recycler. OnTo’s depowering service renders inert most any EOLB packs, modules, and cells. The technology uses a brief, non-toxic treatment applicable to most any chemistry. The industry needs a safe, simple, modular, and inexpensive method to render EOLBs as inert scrap. OnTo’s deactivation system is scalable to the needs of any customer along the EOLB chain of custody. (3) Evidence of Successful Depowering: Untreated batteries will catch fire and explode under abuse conditions such as heat or crush. Slide 2 below shows that untreated batteries will blow-up and expel their internal components with heating, after OnTo’s depowering treatment, the same battery is inert with the same heat treatment (Fig. 7 in the slide). Depowering also removes electrolyte reactivity, eliminating the production of HF and other toxins (Fig 6. in the slide) The depowering process is applicable to large, 26 Ah cells. Fig. 5 in the slide shows the removal of all the electrolyte from whole cells. Removal of flammable material from an EOLB contributes to the inert behavior. OnTo developed this technology through a project supported by the US Department of Energy EERE program, with partners including Seattle King County Metro Transit. While OnTo has generated evidence of successful depowering of batteries, in 2020, a follow-on voucher opportunity for third party analysis of depowered cells and materials was approved through CalTestBed. The expertise of the battery and materials research groups at Lawrence Berkeley National Laboratory will characterize these depowered cells to provide better understanding of the materials level changes in depowering. (4) Pilot Plant for Depowering EOLBs: Making the spoke work in hub-and-spoke While other companies are marketing the hub-and-spoke approach for recycling EOLBs, they rely on dangerous, expensive shredding methods with flimsy IP protection. OnTo offers the only patented, proven ability to depower EOLBs from most any chemistry – at half of the capital cost required for shredding, while eliminating the liability, danger, and waste streams inherent with shredding. The proposed commercial pilot facility is (5) OnTo Technology LLC Company: OnTo develops advanced battery recycling innovations that produce manufacturing quality electrode materials from recycled batteries. Their patented Cathode-healing™ and Deactivation/Depowering processes improve safety and reduce the cost of recycling. OnTo’s breakthrough technologies produce advanced materials for manufacturing batteries useful in applications from portable power to electric vehicles. Contact: Steve Sloop OnTo Technology LLC, 63221 Service Road, STE F, Bend, OR 97703, ssloop@onto-technology.com , 541-389-7897

deactivation↗
DOE OSTI2020

Activated KCNQ1 channel promotes fibrogenic response in hereditary gingival fibromatosis via clustering and activation of Ras

Abstract Background and Objective Activated potassium channels were found to be strongly correlated with gingival overgrowth (GO) phenotype as we reviewed syndromic hereditary gingival fibromatosis (HGF). Nevertheless, the functional roles of potassium channels in gingival fibrosis or gingival overgrowth remained uncovered. The aim of the present study was to explore the pathogenic role of aberrantly activated potassium channel in Hereditary Gingival Fibromatosis (HGF). Methods Gingival tissues were collected from 9 HGF patients and 15 normal controls. Expression of KCNQ1 was detected by immunohistochemistry. Gingival fibroblasts were isolated, and outward K + currents were detected by whole‐cell patch‐clamp analysis, transmembrane potential was determined by flow cytometry. Normal human gingival fibroblasts (NHGFs) were transfected with KCNQ1 adenovirus or treated with KCNQ1 selective agonist ML277 and antagonist chromanol 293B. Accumulation of Extracellular Matrix (ECM) was measured by Western blotting and Sircol Soluble Collagen Assay. Content of secreted TGF‐β1 was measured by ELISA. Active RAS pull‐down assay and cell immunofluorescence were utilized to verify RAS activation. Results KCNQ1 was upregulated in gingival tissues derived from HGF patients and HGF gingival fibroblasts presented increased outward K + currents than NHGFs. Overexpression of KCNQ1, or KCNQ1 agonist ML277, promoted fibrotic responses of NHGFs. TGF‐β1 and KCNQ1 channels formed a positive feed‐back loop. ML277 generated lateral clustering and activation of Ras on plasma membrane, followed by augmented MAPK/AP‐1 signaling pathway output. JNK or ERK1/2 inhibitors suppressed ML277‐induced AP‐1 and ECM upregulation. Conclusion Activation of KCNQ1 potassium channel promoted fibrogenic responses in NHGFs via Ras/MAPK/AP‐1 signaling.

Gao, Qian↗
DOE OSTI2014

Fluorescent labelling of intestinal epithelial cells reveals independent long-lived intestinal stem cells in a crypt

Highlights: • Lentivirus mixed with Matrigel enables direct infection of intestinal organoids. • Our original approach allows the marking of a single stem cell in a crypt. • Time-lapse imaging shows the dynamics of a single stem cell. • Our lentivirus transgene system demonstrates plural long-lived stem cells in a crypt. - Abstract: Background and aims: The dynamics of intestinal stem cells are crucial for regulation of intestinal function and maintenance. Although crypt stem cells have been identified in the intestine by genetic marking methods, identification of plural crypt stem cells has not yet been achieved as they are visualised in the same colour. Methods: Intestinal organoids were transferred into Matrigel® mixed with lentivirus encoding mCherry. The dynamics of mCherry-positive cells was analysed using time-lapse imaging, and the localisation of mCherry-positive cells was analysed using 3D immunofluorescence. Results: We established an original method for the introduction of a transgene into an organoid generated from mouse small intestine that resulted in continuous fluorescence of the mCherry protein in a portion of organoid cells. Three-dimensional analysis using confocal microscopy showed a single mCherry-positive cell in an organoid crypt that had been cultured for >1 year, which suggested the presence of long-lived mCherry-positive and -negative stem cells in the same crypt. Moreover, a single mCherry-positive stem cell in a crypt gave rise to both crypt base columnar cells and transit amplifying cells. Each mCherry-positive and -negative cell contributed to the generation of organoids. Conclusions: The use of our original lentiviral transgene system to mark individual organoid crypt stem cells showed that long-lived plural crypt stem cells might independently serve as intestinal epithelial cells, resulting in the formation of a completely functional villus.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Radiosensitizing effect of gold nanoparticles in carbon ion irradiation of human cervical cancer cells

Noble metal nanoparticles have received considerable attention in biotechnology for their role in bio sensing due to surface plasmon resonance, medical diagnostics due to better imaging contrast and therapy. The radiosensitization effect of gold nanoparticles (AuNP) has been gaining popularity in radiation therapy of cancer cells. The better depth dose profile of energetic ion beam proves its superiority over gamma radiation for fighting against cancer. In the present work, the glucose capped gold nanoparticles (Glu-AuNP) were synthesised and internalized in the HeLa cells. Transmission electron microscopic analysis of ultrathin sections of Glu-AuNP treated HeLa cells confirmed the internalization of Glu-AuNPs. Control HeLa cells and Glu-AuNp treated HeLa cells were irradiated at different doses of 62 MeV 12C ion beam (LET - 290keV/{mu}m) at BIO beam line of using 15UD Pelletron accelerator at Inter University Accelerator Centre, New Delhi, India. The survival fraction was assessed by colony forming assay which revealed that the dose of carbon ion for 90% cell killing in Glu-AuNP treated HeLa cells and control HeLa cells are 2.3 and 3.2 Gy respectively. This observation shows {approx} 28% reduction of {sup 12}C{sup 6+} ion dose for Glu-AuNP treated HeLa cells as compared to control HeLa cells.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2017

Synergistic Effect of LiPF 6 and LiBF 4 as Electrolyte Salts in Lithium-Ion Cells

Recent work shows promise for LiBF 4 as an electrolyte salt for high voltage lithium-ion batteries. LiBF 4 is more hydrolytically stable than LiPF 6 , and in some cases has proved to be more stable at high voltage. This work shows that 1.0 M electrolytes consisting of equal parts LiBF 4 and LiPF 6 have better performance in certain high voltage (4.35 V) lithium-ion cells than electrolytes with LiPF 6 or LiBF 4 alone. This is shown using long-term cycling and ultra-high precision coulometry on lithium-ion cells, with and without electrolyte additives. Ultra-high precision coulometry showed that electrolyte with 1:1 LiPF 6 :LiBF 4 and no other additives performed as well as electrolyte with LiPF 6 and state-of-the-art additive blends in these cells. The synergism between LiPF 6 and LiBF 4 was explored using XPS, symmetric cells and EIS analysis. These show that LiBF 4 reduces impedance growth at the positive electrode, while LiPF 6 improves passivation at the negative electrode.

25 ENERGY STORAGE↗
DOE OSTI2016

SAR11 bacteria linked to ocean anoxia and nitrogen loss

Bacteria of the SAR11 clade constitute up to one half of all microbial cells in the oxygen-rich surface ocean. SAR11 bacteria are also abundant in oxygen minimum zones (OMZs), where oxygen falls below detection and anaerobic microbes have vital roles in converting bioavailable nitrogen to N 2 gas. Anaerobic metabolism has not yet been observed in SAR11, and it remains unknown how these bacteria contribute to OMZ biogeochemical cycling. Here in this paper, genomic analysis of single cells from the world's largest OMZ revealed previously uncharacterized SAR11 lineages with adaptations for life without oxygen, including genes for respiratory nitrate reductases (Nar). SAR11 nar genes were experimentally verified to encode proteins catalysing the nitrite-producing first step of denitrification and constituted ~40% of OMZ nar transcripts, with transcription peaking in the anoxic zone of maximum nitrate reduction activity. Finally, these results link SAR11 to pathways of ocean nitrogen loss, redefining the ecological niche of Earth's most abundant organismal group.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Discovery of high-affinity BCL6-binding peptide and its structure-activity relationship

B cell lymphoma 6 (BCL6) is a transcriptional repressor that interacts with its corepressors BcoR and SMRT. Since this protein-protein interaction (PPI) induces activation and differentiation of B lymphocytes, BCL6 has been an attractive drug target for potential autoimmune disease treatments. Here we report a novel BCL6 inhibitory peptide, F1324 (Ac-LWYTDIRMSWRVP-OH), which we discovered using phage display technology; we also discuss this peptide's structure-activity relationship (SAR). For BCL6(5-129) binding, K{sub D} and IC{sub 50} values of F1324 were 0.57 nM and 1 nM according to the results of an SPR analysis and cell-free ELISA assay, respectively. In contrast, BcoR(Arg498-514Pro) and SMRT(Leu1422-Arg1438) exhibited relatively weak micromole-order binding to BCL6. Furthermore, Fusion protein AcGFP-F1324 transiently expressed in HEK293T cells inhibited intracellular PPI in cell-based M2H assay. By examination of the truncation and fragmentation of F1324, the C-terminal sequence WRVP, which is similar to the BcoR(509-512) sequence WVVP, was identified as being critical for BCL6 binding. In addition, subsequent single-crystal X-ray diffraction analysis of F1324/BCL6(5-129) complex revealed that the high affinity of F1324 was caused by effective interaction of its side chains while its main chain structure was similar to that of BcoR(Arg498-514Pro). To our knowledge, F1324 is the strongest BCL6-binding peptide yet reported. - Highlights: • F1324 was discovered as 5000-times higher affinity peptide to BCL6 than that of BcoR(R498-P514). • X-ray crystal structure analysis revealed the binding mode. • To our knowledge, F1324 is the strongest BCL6-binding and -inhibition peptide so far.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1986

Transition from a planar interface to cellular and dendritic structures during rapid solidification processing

The development of theoretical models which characterize the planar-cellular and cell-dendrite transitions is described. The transitions are analyzed in terms of the Chalmers number, the solute Peclet number, and the tip stability parameter, which correlate microstructural features and processing conditions. The planar-cellular transition is examined using the constitutional supercooling theory of Chalmers et al., (1953) and it is observed that the Chalmers number is between 0 and 1 during dendritic and cellular growth. Analysis of cell-dendrite transition data reveal that the transition occurs when the solute Peclet number goes through a minimum, the primary arm spacings go through a maximum, and the Chalmers number is equal to 1/2. The relation between the tip stability parameter and the solute Peclet number is investigated and it is noted that the tip stability parameter is useful for studying dendritic growth in alloys.

Laxmanan, V.↗
NASA NTRS2003

Ionizing radiation induces heritable disruption of epithelial cell interactions

Ionizing radiation (IR) is a known human breast carcinogen. Although the mutagenic capacity of IR is widely acknowledged as the basis for its action as a carcinogen, we and others have shown that IR can also induce growth factors and extracellular matrix remodeling. As a consequence, we have proposed that an additional factor contributing to IR carcinogenesis is the potential disruption of critical constraints that are imposed by normal cell interactions. To test this hypothesis, we asked whether IR affected the ability of nonmalignant human mammary epithelial cells (HMEC) to undergo tissue-specific morphogenesis in culture by using confocal microscopy and imaging bioinformatics. We found that irradiated single HMEC gave rise to colonies exhibiting decreased localization of E-cadherin, beta-catenin, and connexin-43, proteins necessary for the establishment of polarity and communication. Severely compromised acinar organization was manifested by the majority of irradiated HMEC progeny as quantified by image analysis. Disrupted cell-cell communication, aberrant cell-extracellular matrix interactions, and loss of tissue-specific architecture observed in the daughters of irradiated HMEC are characteristic of neoplastic progression. These data point to a heritable, nonmutational mechanism whereby IR compromises cell polarity and multicellular organization.

Non-NASA Center↗
NASA NTRS1976

Silicon solar cells from transition metal doped Czochralski and web crystals

The influence of metallic impurities on solar cell characteristics has been examined to establish the cost sensitive purity versus performance trade-offs. Solar cells were fabricated on 2 to 4 ohm-cm p-type substrates obtained by Czochralski and dendritic web growth processes. Controlled amounts of metallic impurities were introduced into the melt during growth and included Fe, Cr, Mn, Ni, Cu, Ti, V, Zr, Mg, Zn, and Al. Impurity concentrations in the crystals were determined using emission and mass spectrographic techniques and in some cases by neutron activation analysis. The solar cells were characterized by means of a computer program to curve-fit measured voltage-current data. The principal effect of the added impurities is a degradation of lifetime and diffusion length.

Davis, J. R.↗