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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 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

A Review on Biodegradable Polymeric Materials Striving Towards the Attainment of Green Environment

Polymers are a chain of repeating monomers that can be either non-biodegradable or biodegradable with technical properties for a wide range of applications. The present scenario drives industries to develop new and eco-friendly materials to replace non-biodegradable materials to attain a clean and green environment. Significant research work has been carried out on the development of biocomposites based on biodegradable polymers and natural fibers. The review article addresses the wide range of biodegradable composites that are capable of undergoing degradation by various routes. Our main emphasis has been on the preparation and characterization of biocomposites, using various biodegradable polymers and natural fibers for wide applications like biomedical, packaging, aerospace, agriculture etc. It is clear that blending of reinforcing fibers and fillers with biodegradable polymers significantly enhanced the physical, chemical, biological, mechanical, thermal and biodegradation properties of the base matrix.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2019

A Novel Bacterial Polymeric Silk-Like Protein from a Petroleum Origin Bacillus sp. strain NE: Isolation and Characterization

This paper explores a novel silk-like protein (named Bacillus NE silk (BNES)) isolated from a petroleum origin bacterial strain belongs to the genus Bacillus. The successful characterizations for its chemical structure determination and protein composition have been performed. The results demonstrate that BNES protein is a new type of silk-like protein and has a prospective for applying as a new bacterial silk-like biomaterial. The amino acids constituents of silk-like protein showed that (Ala-Pro-Gly) rich-block protein, are the main major amino acids, while the protein M{sub wt}., was recorded around > ~ 400 kDa, which excelled those similar of natural silk. The degummed or purified silk-like protein was successfully electro-spinned for wet-electrospun silk-like nanofibers using electrospinning technique. Silk-like nanofibers gave an adequate and uniform ribbon-shape structure with average diameter of nanofiber around 110 nm. Meanwhile, the block silk-like protein exhibited high thermal degradation monitored at 140–373 °C, which close those of natural silkworm silk. The purified silk-like protein showed no toxic effect against Vero kidney normal cell-line even after 48 h of incubation, using MTT-assay test. The obtained results demonstrate that, silk-like protein from wild type bacterial origin has potential for use as novel fibrous biomaterials for biomedical and environmental applications.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Toward Greener Polymeric Blends: Study of PBAT/Thermoplastic Whey Protein Isolate/Beeswax Blends

This work evaluated the effects of partial substitution of PBAT by thermoplastic whey protein isolate (WPIT) with addition of beeswax through blends processing and their morphological, mechanical, structural, thermal and rheological properties. Whey protein isolate (WPI) was denatured at 90 °C, using glycerol as plasticizer, to be transformed in a thermoplastic material and subsequently blended with PBAT using a torque rheometer at 130 °C. Addition of 10 and 30% of WPIT in the PBAT matrix was investigated with and without beeswax. Blends were pressed as films with ~ 320 µm of thickness. Scanning electron microscopy (SEM) analysis of PBAT/WPIT blends films revealed the presence of domains. These domains are compounded of whey protein, while at the continuous phase a moderate degree of mixture between PBAT and WPIT was observed by Raman analyses. WPIT did not alter the degree of crystallinity and the glass-transition temperature (T{sub g}) of the PBAT in the blends. Thermogravimetric curves of the blends showed decomposition stages related to WPIT and PBAT phases. Thermal stability of blends decreased in comparison to WPIT, which was associated to the cleavage of disulfide bonds of WPIT during processing and causes other kind of interaction between components. Besides, blends containing WPIT remained non-rigid polymers with Young’s modulus below 70 MPa. The tensile strength and elongation at break decreased due the presence of WPIT. Beeswax did not influence the thermal and mechanical properties explored in this study.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Construction of EGFR peptide gefitinib/quantum dots long circulating polymeric liposomes for treatment and detection of nasopharyngeal carcinoma

Gefitinib/Quantum dots (QDs) loaded peptide long circulating liposomes (G/QDs-P-LCPL) were successfully prepared for treatment and detection by fluorescence labeling for nasopharyngeal carcinoma. Gefitinib was found to have marked inhibition which is dose- and time-dependent. Hoechst 33258 florescence staining and wound-healing assay indicated that as G/QDs-P-LCPL concentration increased, HONE1 staining cells decreased, while the amount of nucleus pyknosis and karyorrhexis grew. Florescence tracing result shows that the drug mainly distributed through tumors. G-P-LCPL target the HONE1 cells and significantly increase the drug uptake efficiency so as to improve the cells inhibit rate compared with the non-targeting group. The EGFR peptide LCPL are potentially useful for drug and fluorescence labeled delivery applications. - Highlights: • Gefitinib/QDs-EGFR peptide liposomes (G/QDs-P-LCPL) were prepared for nasopharyngeal carcinoma treatment and detection. • G-P-LCPL can effectively increase the drug uptake efficiency so as to improve the cells inhibit rate compared with LCPL. • The EGFR peptide LCPL are potentially useful for drug and fluorescence labeled delivery applications.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Bacterial metabolite S-equol modulates glucagon-like peptide-1 secretion from enteroendocrine L cell line GLUTag cells via actin polymerization

Highlights: • Receptors for S-equol were expressed in GLUTag cells. • S-equol increased the intracellular Ca{sup 2+} levels via G{sub q} signaling. • S-equol prevented GLP-1 secretion. • S-equol caused cortical actin reorganization via G{sub q} and G{sub 12/13} pathways. S-equol is one of gut bacterial metabolites produced from soybean isoflavone daizein. While S-equol is known to promote glucose-induced insulin secretion from pancreatic β cells, whether S-equol affects glucagon-like peptide-1 (GLP-1) secretion from enteroendoceine L cells remains unclear. Here we assessed the effect of S-equol on GLP-1 secretion from mouse enteroendocrine L cell line GLUTag cells. GLUTag cells expressed GPR30 and estrogen receptors, which are putative S-equol receptors. Application of S-equol induced an increase in intracellular Ca{sup 2+} levels via GPR30. However, S-equol did not enhance GLP-1 exocytosis, and long-term treatment of S-equol suppressed GLP-1 secretion. Moreover, immunocytochemistry revealed that S-equol increased the density of cortical actin filaments via G{sub 12/13} signaling under GPR30. These data suggest that S-equol prevents GLP-1 secretion as a result of competing regulation between Ca{sup 2+} mobilization and actin reorganization.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

SAXS Assistant: Automated SAXS analysis for structural discovery in biologics and polymeric nanoparticles

Small-angle x-ray scattering (SAXS) is a powerful technique for assessing macromolecular structure. High-throughput SAXS is limited by the time-consuming and, at times, subjective nature of SAXS data interpretation. Here, we present SAXS Assistant, a Python-based script that streamlines SAXS data analysis to extract features for machine learning (ML) and key structural parameters, including the Guinier radius of gyration (R g ), pair distance distribution function (PDDF)-derived R g , maximum particle dimension (D max ), and Kratky plots. The script builds upon BioXTAS RAW and validates reliability via Guinier/PDDF R g agreement, an important indicator of well-measured data sets. For assistance in D max estimation, a multilayer perceptron regressor was trained with 1940 data files from the Small Angle Scattering Biological Data Bank. The model achieved a test set performance R 2 = 0.90 and mean absolute error = 11.7 Å. Training exclusively with experimental data translates analyses from researchers, including experts in the field, to the ML model, which helps assess D max estimations from PDDF. Gaussian mixture model clustering was implemented to classify profiles into structural classes based on entries in the Small Angle Scattering Biological Data Bank. Users may therefore assess the similarity between experimental samples and known biomolecular shapes within the mapped repository entries. This probabilistic clustering aids in quantifying information from Kratky and generating shape-descriptive features. SAXS Assistant accelerates SAXS data analysis through enforced quality control, ML-ready outputs, and flags for low-confidence results. In addition to providing the ability to analyze large data sets at high throughput, this tool is versatile and may serve researchers in both biological and synthetic polymer research fields.

36 MATERIALS SCIENCE↗