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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

miR-125b-5p inhibits breast cancer cell proliferation, migration and invasion by targeting KIAA1522

Highlights: • miR-125b-5p expression was found downregulated in breast cancer. • We explored the tumor suppressive role of miR-125b-5p in breast cancer. • KIAA1522 was reported to function as oncogene in breast cancer. • KIAA1522 was a direct target of miR-125b-5p in breast cancer. Abnormal gene expression due to the dysregulation of microRNAs (miRNAs) often occurred in the initiation or progression of cancers. The aim of this present study was to investigate the function role of miR-125b-5p in breast cancer (BC). Expression levels of miR-125b-5p were determined by quantitative Real-time PCR. Biological functions of miR-125b-5p in the progression of BC were investigated with a series of in vitro experiments including cell counting kit-8 assay, colony formation assay, wound-healing assay and transwell invasion assay. The target of miR-125b-5p in BC was validated by luciferase activity reporter assay and western blot assay. We found miR-125b-5p expression was significantly reduced in BC cell lines compared to the normal breast epithelial cell line. Functional assays showed that cell proliferation, colony formation ability, cell migration, and cell invasion can be suppressed by miR-125b-5p overexpression. Besides, KIAA1522 was validated as a direct target of miR-125b-5p in BC. Collectively, our study showed that miR-125b-5p functions as a tumor suppressor and regulates BC progression through targeting KIAA1522.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Zunyimycin C inhibits the proliferation of lung cancer cells by inducing apoptosis through an AKT-related mechanism

Objective: Zunyimycin C is a novel halogenated type II polyketide derived from the fermentation product of the Streptomyces species with notable antibiotic activity. However, it is still unclear whether zunyimycin C could inhibit the activity of cancer cells. In this study, human lung adenocarcinoma cell line A549, the large-cell lung cancer cell line NCI-H460 and the non-small-cell lung cancer cell line NCI-H1299 were employed to determine the in vitro anticancer properties of zunyimycin C and underlying molecular mechanisms. Materials and methods: The cellular viability and proliferative properties of lung cancer cells were investigated using the Cell Counting Kit-8 and colony formation assay, respectively. The mRNA expression of apoptotic genes related to lung cancer was studied using reverse-transcription polymerase chain reaction. The apoptotic ratio was measured through flow cytometry. The protein expression was visualized via western blotting using specific antibodies. Results: Zunyimycin C could inhibit cell proliferation and induce apoptosis in a dose-dependent manner. The expression levels of apoptosis-related proteins (i.e., BAX, cleaved-caspase-3, and cleaved-caspase-9) were increased compared with the control group. However, the levels of Bcl-2 and phosphorylated AKT were decreased by administration by zunyimycin C. Conclusions: Collectively, these results implied that zunyimycin C could inhibit cell proliferation and induce apoptosis via AKT phosphorylation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Long non-protein coding RNA DANCR functions as a competing endogenous RNA to regulate osteoarthritis progression via miR-577/SphK2 axis

Highlights: • DANCR was increased in OA. • DANCR inhibition suppressed OA chondrocytes proliferation and induced cell apoptosis. • DANCR-miR-577/SphK2 axis play important roles in OA. Long noncoding RNAs (lncRNAs) have been known to be involved in multiple diverse diseases, including osteoarthritis (OA). This study aimed to explore the role of differentiation antagonizing non-protein coding RNA (DANCR) in OA and identify the potential molecular mechanisms. The expression of DANCR in cartilage samples from patients with OA was detected using quantitative reverse transcription–polymerase chain reaction. The effects of DANCR on the viability of OA chondrocytes and apoptosis were explored using cell counting kit 8 assay and flow cytometry assay, respectively. Additionally, the interaction among DANCR, miR-577, and SphK2 was explored using dual-luciferase reporter and RIP assays. The present study found that DANCR was significantly upregulated in patients with OA. Functional assays demonstrated that DANCR inhibition suppressed the proliferation of OA chondrocytes and induced cell apoptosis. The study also showed that DANCR acted as a competitive endogenous RNA to sponge miR-577, which targeted the mRNA of SphK2 to regulate the survival of OA chondrocytes. In conclusion, the study revealed that lncRNA DANCR might promote the proliferation of OA chondrocytes and reduce apoptosis through the miR-577/SphK2 axis. Thus, lncRNA DANCR might be considered as a potential therapeutic target for OA treatment.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Knockdown of Trnau1ap inhibits the proliferation and migration of NIH3T3, JEG-3 and Bewo cells via the PI3K/Akt signaling pathway

Highlights: • Knockdown of Trnau1ap attenuated cellular antioxidant activity. • Knockdown of Trnau1ap reduced cell migration and proliferation. • Knockdown of Trnau1ap blocked the PI3K/Akt signaling pathway. The tRNA selenocysteine 1 associated protein 1 (Trnau1ap, initially named SECp43) is involved in Selenocysteine (Sec) biosynthesis and incorporation into selenoproteins, which play a key role in biological processes, such as embryonic development. We previously reported that downregulation of Trnau1ap inhibited proliferation of cardiomyocyte-like H9c2 cells. However, the effects of Trnau1ap on cell proliferation and migration of embryonic development are not known, and the mechanisms remain elusive. Herein, lentiviral shRNA vectors were transfected in NIH3T3, JEG-3 and Bewo cells (embryonic, trophoblast and placental cells). We found that knockdown of Trnau1ap resulted in reduced expression levels of selenoproteins. The data of Cell Count Kit-8 (CCK-8) assay and wound scratch assay revealed the proliferation and migration rates were reduced in the Trnau1ap-shRNA groups. Furthermore, western blot analysis showed that the phosphorylation level of Akt in the phosphatidylinositol 3-kinase (PI3K)/Akt pathway was attenuated. These results indicate that Trnau1ap plays an important role in regulation of cell proliferation and migration through the PI3K/Akt signaling pathway, as well as being essential for embryonic development by regulating the expression of selenoproteins.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Extracellular IL-37 promotes osteogenic and odontogenic differentiation of human dental pulp stem cells via autophagy

The osteogenic and odontogenic differentiation of dental pulp stem cells (DPSCs) contribute to restoration and regeneration of dental tissue. Previous study indicated that interleukin-37 (IL-37) was an anti-inflammatory factor that affected other pro-inflammatory signals. The aim of this study was to explore the effects of IL-37 on the differentiation of DPSCs. DPSCs were cultured in growth medium with different concentrations of IL-37. We selected the optimal concentration for the following experiments by alkaline phosphatase (ALP) activity analysis, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot. Cell counting kit assay (CCK-8) and 5-Ethynyl-2-Deoxyuridine (EdU) assay were conducted to assess the effects of IL-37 on the proliferation of DPSCs. ALP activity assay and staining, alizarin red S (ARS) staining, qRT‐PCR, Western blot as well as immunofluorescence staining were conducted to assess differentiation ability of DPSCs. Western blot, immunofluorescence staining and transmission electron microscopy (TEM) were utilized to examine cell autophagy. Results showed that IL-37 enhanced the osteogenic and odontogenic differentiation ability of DPSCs with no significant influence on the proliferation of DPSCs. Autophagy in DPSCs was activated by IL-37. Activation of autophagy enhanced osteogenesis and odontogenesis of DPSCs, whereas inhibition of autophagy suppressed DPSCs osteogenic and odontogenic differentiation. In conclusion, IL-37 increased osteogenic and odontogenic differentiation via autophagy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

Microbial ecology of acidic, biogenic gypsum: community structure and distribution of extremophiles on freshly formed and relict sulfate deposits in a hydrogen sulfide-rich cave

Sulfate minerals are abundant on the Martian surface, and many of these evaporite deposits are thought to have precipitated from acidic fluids. On Earth, gypsum (CaSO 4 •2H 2 O) and other sulfates sometimes form under acidic conditions, so exploring the extremophilic life that occurs in these mineral environments can help evaluate the astrobiological potential of acid sulfate depositional settings. Here, we characterized the microbial communities associated with acidic gypsum deposits in a sulfuric acid cave, where sulfate precipitation is driven by sulfide-oxidizing bacteria and archaea. We used 16S rRNA gene sequencing and cell counts to characterize gypsum-associated microorganisms in freshly formed and relict deposits throughout the cave, to test how microbial community composition and abundance would vary with distance from the sulfidic water table and with the concentration of H 2 S(g) and other gases in the cave atmosphere. We found that actively forming gypsum in the lower cave levels was colonized by low-diversity communities that have few cells compared to other environments in the cave. The most abundant taxa were Acidithiobacillus, Metallibacterium, Mycobacteria, and three different Thermoplasmatales-group archaea, which occupied distinct niches based on proximity to sulfidic streams and the concentration of gases in the cave air. By contrast, deposits in older cave levels had more diverse communities that were distinct from those associated with freshly formed gypsum and likely represent a community reliant on different energy resources. These findings show that acidic sulfate deposits serve as habitats for extremophilic microorganisms and broaden our knowledge of the life associated with terrestrial sulfates.

58 GEOSCIENCES↗
NASA NTRS1996

Cardiopulmonary Changes with Moderate Decompression in Rats

Sprague-Dawley rats were compressed to 616 kPa for 120 min then decompressed at 38 kPa/min to assess the cardiovascular and pulmonary responses to moderate decompression stress. In one series of experiments the rats were chronically instrumented with Doppler ultrasonic probes for simultaneous measurement of blood pressure, cardiac output, heart rate, left and right ventricular wall thickening fraction, and venous bubble detection. Data were collected at base-line, throughout the compression/decompression protocol, and for 120 min post decompression. In a second series of experiments the pulmonary responses to the decompression protocol were evaluated in non-instrumented rats. Analyses included blood gases, pleural and bronchoalveolar lavage (BAL) protein and hemoglobin concentration, pulmonary edema, BAL and lung tissue phospholipids, lung compliance, and cell counts. Venous bubbles were directly observed in 90% of the rats where immediate post-decompression autopsy was performed and in 37% using implanted Doppler monitors. Cardiac output, stroke volume, and right ventricular wall thickening fractions were significantly decreased post decompression, whereas systemic vascular resistance was increased suggesting a decrease in venous return. BAL Hb and total protein levels were increased 0 and 60 min post decompression, pleural and plasma levels were unchanged. BAL white blood cells and neutrophil percentages were increased 0 and 60 min post decompression and pulmonary edema was detected. Venous bubbles produced with moderate decompression profiles give detectable cardiovascular and pulmonary responses in the rat.

Robinson, R.↗
NASA NTRS2017

Osteogenic Transcription Regulated by Exaggerated Stretch Loading via Convergent Wnt Signaling

Cell and animal studies conducted onboard the International Space Station and formerly the Shuttle flights have provided data illuminating the deleterious biological response of bone to mechanical unloading. Down regulation of proliferative mechanisms within stem cell populations of the osteogenic niche is a suggested mechanism for loss of bone mass. However the intercellular communicative cues from osteoblasts and osteocytes in managing stem cell proliferation and osteogenic differentiation are largely unknown. In this investigation, MLO-Y4 osteocyte-like and MC3T3-E1 osteoblast-like cells, are co-culture under dynamic tensile conditions and evaluated for phenotypic expression of biochemical signaling proteins influential in driving stem cell differentiation. MLO-Y4 and MC3T3-E1 were co-cultured on polyethersulfone membrane with a 0.45m porosity to permit soluble factor transfer and direct cell-cell gap junction signaling. Cyclic tensile stimulation was applied for 48 h at a frequency of 0.1Hz and strain of 0.1. Total Live cell counts indicate mechanical activation of MC3T3-E1s inhibits proliferation while MLO-Y4s increase in number. However, the percent of live MLO-Y4s within the population is low (46.3 total count, *p0.05, n4) suggesting a potential apoptotic signaling cascade. Immunofluorescence demonstrated that stimulation of co-cultures elicits increased gap junction communication. Previously reported PCR evaluation of osteogenic markers further corroborate that the co-cultured populations communicative networks play a role in translating mechanical signals to molecular messaging. These findings suggest that an osteocyte-osteoblast signaling feedback mechanism may regulate mechanotransduction of an apoptotic cascade within osteocytes and transcription of cytokine signaling proteins responsible for stem cell niche recruitment much more directly than previously believed.

mechanical stimulation↗
DOE OSTI2018

High glucose downregulates the effects of autophagy on osteoclastogenesis via the AMPK/mTOR/ULK1 pathway

Highlights: • High glucose downregulates AMPK/mTOR/ULK pathway in osteoclasts. • Inhibition of AMPK/mTOR/ULK pathway suppresses autophagy in glucose-mediated osteoclastogenesis. • Autophagy has a positive correlation with glucose-mediated osteoclastogenesis. Diabetes is a chronic disease that disrupts the balance between bone formation and bone desorption, which can lead to osteoporosis, increasing the risk of fracture. However, compared with osteoblasts, the biological effects of hyperglycemia on osteoclastogenesis remain to be elucidated. Therefore, we investigated the impact of glucose at different concentrations (5.5, 10.5, 15.5, 20.5, 25.5, and 30.5 mM) on osteoclastogenesis using RAW264.7 cells. Cell proliferation was measured with the cell counting kit-8 assay, and osteoclastogenesis was detected with tartrate-resistant acid phosphatase staining and bone resorption assays, as well as protein cathepsin K expression. Compound C, the AMP-activated protein kinase (AMPK) pathway inhibitor, was used to examine the relationship between the AMPK/mTOR/ULK1 signaling pathway and autophagy in osteoclasts. Autophagy was evaluated with transmission electron microscopy and immunofluorescence microscopy and associated proteins were detected with western blotting. The pharmacological autophagic reagents bafilomycin A1, 3-methyladenine, and rapamycin were used to determine the effect of autophagy on osteoclastogenesis. Our results showed that glucose negatively affected osteoclast formation and function but did not affect the proliferation of RAW264.7 cells. Suppression of the AMPK/mTOR/ULK1 signaling axis decreased autophagy in glucose-mediated osteoclast. Furthermore, High levels of glucose decreased autophagy level in osteoclasts. Additionally, interfering with autophagy affected osteoclast formation and function. These findings clarify the mechanisms underlying the effects of glucose-mediated osteoclastogenesis and will help identify novel therapeutic strategies for the protection of skeletal health in diabetic osteoporosis.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1992

Studies on penetration of antibiotic in bacterial cells in space conditions (7-IML-1)

The Cytos 2 experiment was performed aboard Salyut 7 in order to test the antibiotic sensitivity of bacteria cultivated in vitro in space. An increase of the Minimal Inhibitory Concentration (MIC) in the inflight cultures (i.e., an increase of the antibiotic resistance) was observed. Complementary studies of the ultrastructure showed a thickening of the cell envelope. In order to confirm the results of the Cytos 2 experiment, we performed the ANTIBIO experiment during the D1 mission to try to differentiate, by means of the 1 g centrifuge in the Biorack, between the biological effects of cosmic rays and those caused by microgravity conditions. The originality of this experiment was in the fact that it was designed to test the antibiotic sensitivity of bacteria cultivated in vitro during the orbital phase of the flight. The results show an increase in resistance to Colistin in in-flight bacteria. The MIC is practically double in the in-flight cultures. A cell count of living bacteria in the cultures containing the different Colistin concentrations showed a significant difference between the cultures developed during space flight and the ground based cultures. The comparison between the 1 g and 0 g in-flight cultures show similar behavior for the two sets. Nevertheless, a small difference between the two sets of ground based control cultures was noted. The cultures developed on the ground centrifuge (1.4 g) present a slight decrease in comparison with the cultures developed in the static rack (1 g). In order to approach the mechanisms of the increase of antibiotic resistance on bacteria cultivated in vitro in space, we have proposed the study on penetration of antibiotics in bacterial cells in space conditions. This experiment was selected for the International Microgravity Laboratory 1 (IML-1) mission.

Tixador, R.↗
DOE OSTI2021

Mathematical model of a personalized neoantigen cancer vaccine and the human immune system

Cancer vaccines are an important component of the cancer immunotherapy toolkit enhancing immune response to malignant cells by activating CD4 + and CD8 + T cells. Multiple successful clinical applications of cancer vaccines have shown good safety and efficacy. Despite the notable progress, significant challenges remain in obtaining consistent immune responses across heterogeneous patient populations, as well as various cancers. We present a mechanistic mathematical model describing key interactions of a personalized neoantigen cancer vaccine with an individual patient’s immune system. Specifically, the model considers the vaccine concentration of tumor-specific antigen peptides and adjuvant, the patient’s major histocompatibility complexes I and II copy numbers, tumor size, T cells, and antigen presenting cells. We parametrized the model using patient-specific data from a clinical study in which individualized cancer vaccines were used to treat six melanoma patients. Model simulations predicted both immune responses, represented by T cell counts, to the vaccine as well as clinical outcome (determined as change of tumor size). This model, although complex, can be used to describe, simulate, and predict the behavior of the human immune system to a personalized cancer vaccine.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Effects of amiloride on physiological activity of stem cells of human lung cancer and possible mechanism

Lung cancer is a common malignant tumor, the cancer stem cells (CSCs) were regarded responsible for the development of cancer tissue. The effects of amiloride on lung cancer stem cells and the possible mechanism were not much investigated. In this study, human NCI-H1975 lung CSCs were selected by flow cytometry, and the effects of amiloride at different concentrations (0, 12.5, 25, 50, and 100 μmol/L) were evaluated on proliferation, migration, invasion and apoptosis of CSCs using cell counting kit-8 and Transwell migration assays as well as flow cytometry. Wstern blot analysis was performed to investigate the effect of amiloride on the level of proteins in uPA system, NF-kB pathway, and PI3K-AKT-mTOR pathway in CSCs. As a result, we found that amiloride inhibited proliferation, migration and invasion of lung CSCs, and promoted apoptosis. Further, we found that amiloride decreased levels of target proteins in the uPA system, as well as the NF-kB and PI3K-AKT-mTOR pathways. These results indicated that amiloride could inhibit proliferation, migration and invasion of lung CSCs, and promotes apoptosis, these effects may be related to decreased levels of proteins in the uPA system, the NF-kB pathway, and the PI3K-AKT-mTOR pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Retinoic acid modulates iron metabolism imbalance in anemia of inflammation induced by LPS via reversely regulating hepcidin and ferroportin expression

Highlights: • Anemia of inflammation (AI) model was induced by lipopolysaccharide in mouse. • Retinoic acid (RA) increases RBC, Hb, HCT, MCV, MCHC and EPO in AI model. • RA inhibits inflammation in AI model by decreasing TNF-α, IL-18 and IL-1β contents. • RA modulates iron metabolism imbalance in AI model. • RA reversely regulates hepcidin and ferroportin expression in AI model. The present study was designed to investigate the effect of retinoic acid (RA) on anemia of inflammation (AI) induced by lipopolysaccharide (LPS) and explore the potential mechanisms. BALB/c mice were randomly assigned into four groups: control group; LPS (10 mg/kg) group, LPS + RA (3 mg/kg) and LPS + RA (15 mg/kg) groups. Red blood cell count (RBC), hemoglobulin (Hb), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin contentration (MCHC), erythropoietin (EPO) and iron content in both serum and liver tissue were measured. The AI model induced by LPS was successfully established represented by the decreases in RBC, Hb, HCT, MCV, MCHC and EPO for anemia indicators and by the increases in TNF-α, IL-18 and IL-1β contents for inflammation indicators. However, supplementation of RA increased the levels of anemia indicators and decreased the content of inflammation indicators. In addition, RA increased the content of iron in serum, while decreased its content in liver tissue. Furthermore, RA down-regulated the protein expression of hepcidin, toll-like receptor 4 (TLR4) and p-p65 in liver tissue, while up-regulated that of ferroportin. RA modulates iron metabolism imbalance in AI induced by LPS via reversely regulating hepcidin and ferroportin expression, which might be mediated by TLT-4/NFκB signaling pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

N, N’-disubstitutedphenyl-4-ethoxyl benzene-1, 3-disulfonamides: design, synthesis, and evaluation of anti-platelet aggregation activity

According to the bio-isosterism theory, a series of N, N’-disubstitutedphenyl-4-ethoxylbenzene-1, 3-disulfonamides (5a-p) were designed and synthesized by two steps of reactions including chlorosulfonation and ammonolysis. The structures of all compounds have been confirmed by IR, {sup 1}H-NMR, {sup 13}C-NMR, and ESI-MS spectra. The in vitro anti-platelet aggregation activities were evaluated by Born’s test induced by adenosine diphosphate (ADP) and arachidonic acid (AA), respectively. The biological evaluation results revealed that compound 5h had the lowest IC{sub 50} value (0.32 μM) and the highest inhibition rate (40.9 %) that of three positive control agents clopidogrel (0.41 μM, 23.5 %), aspirin (0.53 μM, 28.9 %), and picotamide (0.76 μM, 32.7 %). Afterwards, compounds with higher activities were selected to further study in vitro cytotoxicity via cell counting kit-8 (CCK-8) assay. The cytotoxicity results indicated that compound 5h had simultaneously the lowest cytotoxicity, while other compounds had no significant relationship between the anti-platelet activities and cytotoxicities. Based on above in vitro anti-platelet activity data, the SAR (Structure Activity Relationship) of the target compounds was preliminarily summarized. In general, N, N’-disubstitutedphenyl-4-ethoxylbenzene-1, 3-disulfonamides have the potential of further study and very likely become safer and more effective anti-platelet agents.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Hydrophilic Stent Coating Inhibits Platelet Adhesion on Stent Surfaces: Initial Results In Vitro

BackgroundEndovascular stents and flow diverter stents (FDS) have revolutionized the treatment of intradural aneurysms; however, the need for dual anti-platelet treatment (DAPT) limits their use and can cause additional issues. Therefore, there is a need to develop stent coatings that negate the need for DAPT.MethodsTwo different hydrophilic polymer coatings (HPC-I and HPC-II) were used to coat small nickel titanium plates to initially test the hydrophilic properties of these coatings when applied to nickel titanium. The plates were subsequently incubated with non-medicated whole blood from healthy volunteers for 10 min and stained with a CD61 immunofluorescent antibody that allows detection of adherent platelets. The coatings were applied to FDS wires and were again incubated with non-medicated whole blood from the same volunteers. Scanning electron microscopy was used to detect adherent platelets on the wire surface.ResultsThe HPC-II coating (1.12 ± 0.4%) showed a significantly lower CD61 +ve cell count (p ≤ 0.001) compared to both uncoated NiTi plates (48.61 ± 7.3%) and those with the HPC-I coating (mean 40.19 ± 8.9%). Minimal adherent platelets were seen on the FDS nickel titanium wires coated with the HPC-II compared to uncoated FDS under electron microscopy.ConclusionThere is a significant decrease in the number of adherent CD61 +ve platelets on nickel titanium surfaces coated with the HPC-II coating compared to uncoated surfaces. The coating can be successfully applied to the wires of flow diverters. The results of this study are promising with regard to the development of new anti-thrombogenic endovascular devices.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Impact of artificial topological changes on flow and transport through fractured media due to mesh resolution

Abstract We performed a set of numerical simulations to characterize the interplay of fracture network topology, upscaling, and mesh refinement on flow and transport properties in fractured porous media. We generated a set of generic three-dimensional discrete fracture networks at various densities, where the radii of the fractures were sampled from a truncated power-law distribution, and whose parameters were loosely based on field site characterizations. We also considered five network densities, which were defined using a dimensionless version of density based on percolation theory. Once the networks were generated, we upscaled them into a single continuum model using the upscaled discrete fracture matrix model presented by Sweeney et al. (2019). We considered steady, isothermal pressure-driven flow through each domain and then simulated conservative, decaying, and adsorbing tracers using a pulse injection into the domain. For each simulation, we calculated the effective permeability and solute breakthrough curves as quantities of interest to compare between network realizations. We found that selecting a mesh resolution such that the global topology of the upscaled mesh matches the fracture network is essential. If the upscaled mesh has a connected pathway of fracture (higher permeability) cells but the fracture network does not, then the estimates for effective permeability and solute breakthrough will be incorrect. False connections cannot be eliminated entirely, but they can be managed by choosing appropriate mesh resolution and refinement for a given network. Adopting octree meshing to obtain sufficient levels of refinement leads to fewer computational cells (up to a 90% reduction in overall cell count) when compared to using a uniform resolution grid and can result in a more accurate continuum representation of the true fracture network.

58 GEOSCIENCES↗
DOE OSTI2018

Electrospun ZnO Nanoparticles Doped Core–Sheath Nanofibers: Characterization and Antimicrobial Properties

Coaxial electrospinning technique was used to fabricate the core–sheath composite nanofibers of ZnO nanoparticle (Nps) (10%, 20% w/w) doped polymethyl methacrylate (PMMA) (as sheath) and polyvinyl alcohol (PVA) (as core). Fourier transform infrared (FT-IR) spectra were confirmed the weak forces arise between ZnO Nps, PMMA and PVA matrixes. The hexagonal (wurtzite) structure of ZnO Nps with ~ 30.8 nm of diameter was confirmed from the X-ray diffraction pattern. The morphology and microstructure of core–sheath composite nanofibers were confirmed from the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is clearly seen from the TEM images that the PMMA encapsulate the PVA core. Core–sheath composite nanofibers were assessed against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) bacteria through quantitative, disk diffusion and viable cell count methods. It was found that ZnO Nps doped core–sheath nanofibers were effectively inhibit the growth of gram positive bacteria, B. subtilis.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Data-Driven Model Validation Across Dimensions

Data-driven model validation across dimensions in mathematical and computational biology assumptions are often made (e.g., symmetry) to reduce the problem from three spatial dimensions (3D) to two (2D). However, some experimental datasets, such as cell counts obtained via flow cytometry, represent the entire 3D biological object. For purpose of model calibration and validation, it is sometimes necessary to compare these biological datasets with model outputs. In this work, we propose a methodology for scaling 2D model outputs to compare with 3D experimental datasets, and we discuss the application of this methodology to two examples: agent-based models of granuloma formation and skeletal muscle tissue. The accuracy of the method is evaluated in artificially generated scenarios.

97 MATHEMATICS AND COMPUTING↗