Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “CCl3”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

Materials Data on CCl3 by Materials Project

CCl3 crystallizes in the orthorhombic Fmm2 space group. The structure is zero-dimensional and consists of four chlorine molecules and eight dichloromethane molecules.

36 MATERIALS SCIENCE↗

Ultraviolet absorption cross-sections of some carbonyl compounds and their temperature dependence

Ultraviolet absorption cross-section of phosgene (CCl2O), trichloroacetylchloride (CCl3-CClO) and trichloroacetaldehyde (CCl3-CHO) have been measured between 170 and 320 nm for temperature ranging from 210 to 295 K with classical double beam equipment. These data are compared with other available determinations performed at room temperature. Photodissociation coefficients are estimated and their temperature dependence is discussed. Impact of the photodissociation on the total atmospheric destruction of these compounds is illustrated.

Gillotay, D.↗

Acute Exposure to Aerosolized Nanoplastics Modulates Redox-Linked Immune Responses in Human Airway Epithelium

Micro- and nanoplastics (MPs and NPs) are pervasive environmental pollutants detected in aquatic ecosystems, with emerging evidence suggesting their presence in airborne particles generated by water body motion. Inhalation exposure to airborne MPs and NPs remains understudied despite documented links between occupational exposure to these particles and adverse respiratory outcomes, including airway inflammation, oxidative stress, and chronic respiratory diseases. This study explored the effects of acute NP exposure on a fully differentiated 3D human airway epithelial model derived from 14 healthy donors. Airway epithelium was exposed to aerosolized 50 nm polystyrene NPs at concentrations ranging from 2.5 to 2500 µg/mL for three minutes per day over three days. Functional assays revealed no significant alterations in tissue integrity, cell survival, mucociliary clearance, or cilia beat frequency, suggesting intact epithelial function post-exposure. However, cytokine and chemokine profiling identified a significant five-fold increase in CCL3 (MIP-1α), a neutrophilic chemoattractant, in NP-exposed samples compared to controls. This was corroborated by increased neutrophil chemotaxis in response to conditioned media from NP-exposed tissues, indicating a pro-inflammatory neutrophilic response. Conversely, levels of interleukins (IL-21, IL-2, IL-15), CXCL10, and TGF-β were significantly reduced, suggesting immunomodulatory effects that may impair adaptive immune responses and tissue repair mechanisms. These findings demonstrate that short-term exposure to NP-containing aerosols induces a distinct pro-inflammatory response in airway epithelium, characterized by enhanced neutrophil recruitment and reduced secretion of key immune modulators. These findings underscore the potential for aerosolized NPs to induce oxidative and inflammatory stress, raising concerns about their long-term impact on respiratory health and redox regulation.

Biochemistry & Molecular Biology↗

Photodecomposition of chloromethanes adsorbed on silica surfaces

Irradiation of CCl4, CFCl3, and CF2Cl2 in the presence of C2H6 in vessels containing silica sand or fused quartz tubing results in the formation of chlorine-containing products. The formation of these compounds occurs at wavelengths extending up to approximately 400 nm, that is, at wavelengths well beyond the absorption threshold of the chloromethanes in the gas phase. It is suggested that CCl4 adsorbed on silica surfaces photodissociates to yield CCl3 and CCl2 species. The poor material balance obtained in these experiments indicates that several of the chlorine-containing fragments are strongly adsorbed on the surface. At a CCl4 pressure of 13 Pa (0.1 torr), photolysis with 366 nm light in the presence of sand results in the decomposition of one molecule for every 10,000 photons striking the surface. Under otherwise identical conditions, the photon-induced breadkdown of CFCl3 and CF2Cl2 is respectively only 10% or 3% as efficient.

Ausloos, P.↗

Mixing ratios of trace gases in the austral polar atmosphere during August and September of 1987

Mixing ratios are presented for a number of long-lived trace gases in the austral polar atmosphere during August and September of 1987. The recent discovery of a 12-year trend of increasing depletion of ozone over the Antarctic Continent in the spring of each year led to numerous theoretical interpretations and several scientific expeditions to the region. The results herein were obtained as part of a major effort involving penetration of the region of ozone depletion by NASA's multi-instrumented aircraft. One of the 14 instruments on the high-altitude ER-2 aircraft collected pressurized air samples between latitudes of 53 degrees and 72 degrees south at pressure altitudes up to 21 km in a series of 12 flights from Punta Arenas, Chile, over the Palmer Peninsula. The sampling system, located in the nose section of ER-2, has an inlet tube in the free airstream, a metal-bellows air pump, and 14 specially treated 1.6 l stainless-steel canisters for containing the pressurized air at 350 kPa. A typical flight profile consisted of a southbound path on the 428 K potential temperature surface, a descent to a pressure altitude of 13.7 km, a climb to the 460 K surface, and return on this surface. Mixing ratios for the trace gases were obtained from gas chromatographic analyses of the pressurized air samples. Of the species measured, the mixing ratios for CH4, CO, N2O, CF2 Cl2, CFCl3, CH3, CCl3, CCl4, and C2F3Cl3 are reported here.

Vedder, James F.↗

Comparison of experimental and calculated attachment rate constants for CFCl3 and CCl4 in the temperature range 294-500 K

Electron-attachment cross sections and rate constants have been measured and calculated for the dissociative attachment processes e + CFCl3 - Cl(-) + CFCl2 and e + CCl4 - Cl(-) + CCl3. Good agreement over the electron-energy range 1-200 meV is found in energy dependence between present calculated cross sections and experimental cross sections at 300 K. The same calculation, with suitable adjustment of thermal populations, was used to calculate electron-attachment rate constants in the range 50-600 K. Experimental rate constants for CFCl3 and CCl4 were measured at temperatures of 294, 404, and 496 K (CFCl3) and 294, 400, and 500 K (CCl4) using the Cavalleri electron-density sampling method. Good agreement is found between present measurements and calculations, poor agreement with flowing-afterglow Langmuir-probe (FALP) data in CFCl3 at the higher temperatures, and reasonable agreement with FALP data for CCl4.

Orient, O. J.↗

Proposed reference models for CO2 and halogenated hydrocarbons

The vertical distribution of carbon dioxide, halocarbons and their sink products, HCl and HF, have become available, mainly by means of balloon measurements. Most measurements were made at northern mid-latutudes, but some constituents were measured at tropical latitudes and in the Southern Hemisphere as well. An attempt is made here to combine the available data for presentation of reference models for CO2, CCl4 CCl3F, CCl2F2, CClF3, CF4, CCl2F-CClF2, CClF2-CClF2, CClF2-CF3, CF3-CF3, CH3Cl, CHClF2, CH3-CCl3, CBrClF2, CBrF3, HCl and HF.

Fabian, P.↗

First Global Observations of Atmospheric COCIF from the Atmospheric Chemistry Experiment Mission

Carbonyl chlorofluoride (COCIF) is an important reservoir of chlorine and fluorine in the Earth's atmosphere. Satellite-based remote sensing measurements of COCIF, obtained by the Atmospheric Chemistry Experiment (ACE) for a time period spanning February 2004 through April 2007, have been used in a global distribution study. There is a strong source region for COCIF in the tropical stratosphere near 27 km. A layer of enhanced COCIF spans the low- to mid-stratosphere over all latitudes, with volume mixing ratios of 40-100 parts per trillion by volume, largest in the tropics and decreasing toward the poles. The COCIF volume mixing ratio profiles are nearly zonally symmetric, but they exhibit a small hemispheric asymmetry that likely arises from a hemispheric asymmetry in the parent molecule CCl3 F. Comparisons are made with a set of in situ stratospheric measurements from the mid-1980s and with predictions from a 2-D model.

Fu, Dejian↗

Persistent Expression Changes of Fibrosis Related Genes in the Lung Tissues of Rats Exposed to Lunar Dust Particles

The Moon's surface is covered by a layer of reactive dust, containing 1-2% of respirable fine dust (< 3 microns). The habitable area of any lunar landing vehicle would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to evaluate the toxicity of Apollo moon dust in rodents through inhalation to assess the health risk of dust exposures to humans and to identify the mechanisms and potential pathways involved in lunar dust-induced toxicity. Ccl3, Ccl12, Cxcl2, Cxcl5, Itgb8, Tnf, Ldhc, Clec4e, Bmp7, and Smad6, showed persistently significant expression changes in the lung tissue. The expression of several of these genes were dose- and time- dependent, and were significantly correlated with other pathological. Our previous data showed that no pathological changes were detected in low dose groups. However, several genes, primarily produced by lung epithelial, were significantly altered persistently in response to low-dose dust exposure. The data presented in this study, for the first time, explores the molecular mechanisms of lunar dust induced toxicity, contributing not only the risk assessment for future space exploration, but also understandings of the dust-induced toxicity to humans on earth.

Zhang, Ye↗

Prostate cancer-associated secreted proteins

Methods are provided for treating a subject with prostate cancer and/or diagnosing a subject at risk for prostate cancer, which can include measuring increased expression of at least two prostate cancer-related molecules in a sample obtained from a subject, including the prostate cancer-related molecules AGR2, AGR3, CRISP3, CCL3, CEACAM5, CEACAM6, IL24, MMP9, CXCL14, CD90, POSTN, and SFRP4. The methods can include administering at therapy to a subject with prostate cancer. Methods are provided for treating a subject with intermediate- or high-risk prostate cancer, which can include measuring increased expression of MMP9 in a sample obtained from a subject compared to a control representing expression of MMP9 expected in a sample from a subject who has low-risk prostate cancer.

59 BASIC BIOLOGICAL SCIENCES↗