Lewy Body Disease

MedlinePlus

Lewy body disease is one of the most common causes of dementia in the elderly. Dementia is the loss of mental ... to affect normal activities and relationships. Lewy body disease happens when abnormal structures, called Lewy bodies, build ...

Splitter-bladed centrifugal compressor impeller designed for automotive gas turbine application. [at the Lewis Research Center

NASA Technical Reports Server (NTRS)

Pampreen, R. C.

1977-01-01

Mechanical design and fabrication of two splitter-bladed centrifugal compressor impellers were completed for rig testing at NASA Lewis Research Center. These impellers were designed for automotive gas turbine application. The mechanical design was based on NASA specifications for blade-shape and flowpath configurations. The contractor made engineering drawings and performed calculations for mass and center-of-gravity, for stress and vibration analyses, and for shaft critical speed analysis. One impeller was machined to print; the other had a blade height and exit radius of 2.54 mm larger than print dimensions.

Unraveling the Complexities: An Investigation of the Factors That Induce Load in Chemistry Students Constructing Lewis Structures

ERIC Educational Resources Information Center

Tiettmeyer, Jessica M.; Coleman, Amelia F.; Balok, Ryan S.; Gampp, Tyler W.; Duffy, Patrick L.; Mazzarone, Kristina M.; Grove, Nathaniel P.

2017-01-01

Mastering the ability to construct and manipulate Lewis structures is an important first step along the journey to reaching representational competence. Lewis structures serve as a convenient organizational scheme that can help students to scaffold their chemical knowledge and help them to apply it to predict a variety of physical and chemical…

Fort Lewis Dining Facilities Consumer Survey

DTIC Science & Technology

survey was to identify those factors which have the potential for influencing or determining consumer attendance at the dining hall. In general, the...an improvement of quality, preparation, and quantity of the food would be all that is necessary to draw the military customer back into the dining hall

The "Commodification of Higher Education" Myth

ERIC Educational Resources Information Center

Chaplin, David; Forseth, Nate

2015-01-01

Despite concerns over the commodification of higher education in North America, Great Britain, and Oceania (Shumar, 1997; Sappey, 2005; Kaye, Bickel & Birtwistle, 2006; Lewis, 2010) the evidence does not justify such fears. Drawing on price elasticity of demand data and enrollment patterns for public, elite private (Ivy League) and Council for…

Estimating forest structure parameters within Fort Lewis Military Reservation using airborne laser scanner (LIDAR) data.

Treesearch

Hans-Erik Andersen; Jeffrey R. Foster; Stephen E. Reutebuch

2003-01-01

Three-dimensional (3-D) forest structure information is critical to support a variety of ecosystem management objectives on the Fort Lewis Military Reservation, including habitat assessment, ecological restoration, fire management, and commercial timber harvest. In particular, the Forestry Program at Fort Lewis requires measurements of shrub, understory, and overstory...

The Fundamental Ontology of Study

ERIC Educational Resources Information Center

Lewis, Tyson E.

2014-01-01

In an effort to disrupt the hegemonic dominance of learning theory, in this article Tyson Lewis explores the unique educational logic of studying. Drawing on the work of Giorgio Agamben, we can understand the operation of study as one of suspension through three modes: preferring not; no longer, not yet; and as not. But the relationship between…

A Challenge to Vocational Educators. Patrick J. O'Connor Distinguished Scholars. 1994 Papers.

ERIC Educational Resources Information Center

Phillips, Maria; Burrell, Lewis

This document contains two papers dealing with challenges facing vocational educators. "Producing a Competent Workforce for the Year 2000: Industry Expectations of Education" (Lewis Burrell) draws the following conclusions: (1) employers and educators need to form a close coalition to plan, design, and execute a system of education and training…

Technology Transferred to the Kirby Company

NASA Technical Reports Server (NTRS)

1996-01-01

NASA Lewis Research Center's Propulsion Systems Branch, evaluated the structural and vibration characteristics of the Kirby Model G-4 fan. Modes of vibration and resonance potential were evaluated in the Holography Test Lab at Lewis. As a result of the Lewis tests and rotor structural evaluation, Kirby engineers gained new insights into their existing design, enabling them to develop a more robust fan for use in their vacuum cleaners.

Zwitterionic versus canonical amino acids over the various defects in zeolites: A two-layer ONIOM calculation

PubMed Central

Yang, Gang; Zhou, Lijun

2014-01-01

Defects are often considered as the active sites for chemical reactions. Here a variety of defects in zeolites are used to stabilize zwitterionic glycine that is not self-stable in gas phase; in addition, effects of acidic strengths and zeolite channels on zwitterionic stabilization are demonstrated. Glycine zwitterions can be stabilized by all these defects and energetically prefer to canonical structures over Al and Ga Lewis acidic sites rather than Ti Lewis acidic site, silanol and titanol hydroxyls. For titanol (Ti-OH), glycine interacts with framework Ti and hydroxyl sites competitively, and the former with Lewis acidity predominates. The transformations from canonical to zwitterionic glycine are obviously more facile over Al and Ga Lewis acidic sites than over Ti Lewis acidic site, titanol and silanol hydroxyls. Charge transfers that generally increase with adsorption energies are found to largely decide the zwitterionic stabilization effects. Zeolite channels play a significant role during the stabilization process. In absence of zeolite channels, canonical structures predominate for all defects; glycine zwitterions remain stable over Al and Ga Lewis acidic sites and only with synergy of H-bonding interactions can exist over Ti Lewis acidic site, while automatically transform to canonical structures over silanol and titanol hydroxyls. PMID:25307449

Developing Identity and Agency as an Early Career Academic: Lessons from Alice

ERIC Educational Resources Information Center

Monk, Sue; McKay, Loraine

2017-01-01

This paper draws on Lewis Carroll's character of Alice as a metaphor for interrogating identity construction and agency amongst early career academics, a process which can seem like Alice's pursuit of the White Rabbit in a strange land. Keeping in mind the effects of neoliberalism on the tertiary sector, we recognise the centrality of personal…

Development and Validation of the Implicit Information from Lewis Structures Instrument(IILSI): Do Students Connect Structures with Properties?

ERIC Educational Resources Information Center

Cooper, Melanie M.; Underwood, Sonia M.; Hilley, Caleb Z.

2012-01-01

Lewis structures are a simplified two dimensional "cartoon" of molecular structure that allow a knowledgeable user to predict the types of properties a particular substance may exhibit. However, prior research shows that many students fail to recognize these structure-property connections and are unable to decode the information…

Structural Ceramics

NASA Technical Reports Server (NTRS)

1986-01-01

This publication is a compilation of abstracts and slides of papers presented at the NASA Lewis Structural Ceramics Workshop. Collectively, these papers depict the scope of NASA Lewis' structural ceramics program. The technical areas include monolithic SiC and Si3N4 development, ceramic matrix composites, tribology, design methodology, nondestructive evaluation (NDE), fracture mechanics, and corrosion.

NASA Lewis Research Center/university graduate research program on engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1985-01-01

NASA Lewis Research Center established a graduate research program in support of the Engine Structures Research activities. This graduate research program focuses mainly on structural and dynamics analyses, computational mechanics, mechanics of composites and structural optimization. The broad objectives of the program, the specific program, the participating universities and the program status are briefly described.

NASA Lewis Research Center/University Graduate Research Program on Engine Structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1985-01-01

NASA Lewis Research Center established a graduate research program in support of the Engine Structures Research activities. This graduate research program focuses mainly on structural and dynamics analyses, computational mechanics, mechanics of composites and structural optimization. The broad objectives of the program, the specific program, the participating universities and the program status are briefly described.

Difficulty Processing Temporary Syntactic Ambiguities in Lewy Body Spectrum Disorder

ERIC Educational Resources Information Center

Grossman, Murray; Gross, Rachel G.; Moore, Peachie; Dreyfuss, Michael; McMillan, Corey T.; Cook, Philip A.; Ash, Sherry; Siderowf, Andrew

2012-01-01

While grammatical aspects of language are preserved, executive deficits are prominent in Lewy body spectrum disorder (LBSD), including Parkinson's disease (PD), Parkinson's dementia (PDD) and dementia with Lewy bodies (DLB). We examined executive control during sentence processing in LBSD by assessing temporary structural ambiguities. Using an…

Structural features of N-glycans linked to glycoproteins expressed in three kinds of water plants: Predominant occurrence of the plant complex type N-glycans bearing Lewis a epitope.

PubMed

Maeda, Megumi; Tani, Misato; Yoshiie, Takeo; Vavricka, Christopher J; Kimura, Yoshinobu

2016-11-29

The Japanese cedar pollen allergen (Cry j1) and the mountain cedar pollen allergen (Jun a1) are glycosylated with plant complex type N-glycans bearing Lewis a epitope(s) (Galβ1-3[Fucα1-4]GlcNAc-). The biological significance of Lewis a type plant N-glycans and their effects on the human immune system remain to be elucidated. Since a substantial amount of such plant specific N-glycans are required to evaluate immunological activity, we have searched for good plant-glycan sources to characterize Lewis a epitope-containing plant N-glycans. In this study, we have found that three water plants, Elodea nuttallii, Egeria densa, and Ceratophyllum demersum, produce glycoproteins bearing Lewis a units. Structural analysis of the N-glycans revealed that almost all glycoproteins expressed in these three water plants predominantly carry plant complex type N-glycans including the Lewis a type, suggesting that these water plants are good sources for preparation of Lewis a type plant N-glycans in substantial amounts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Who Needs Lewis Structures to Get VSEPR Geometries?

ERIC Educational Resources Information Center

Lindmark, Alan F.

2010-01-01

Teaching the VSEPR (valence shell electron-pair repulsion) model can be a tedious process. Traditionally, Lewis structures are drawn and the number of "electron clouds" (groups) around the central atom are counted and related to the standard VSEPR table of possible geometries. A simpler method to deduce the VSEPR structure without first drawing…

Lewis Structures Technology, 1988. Volume 1: Structural Dynamics

NASA Technical Reports Server (NTRS)

1988-01-01

The specific purpose of the symposium was to familiarize the engineering structures community with the depth and range of research performed by the Structures Division of the Lewis Research Center and its academic and industrial partners. Sessions covered vibration control, fracture mechanics, ceramic component reliability, parallel computing, nondestructive testing, dynamical systems, fatigue and damage, wind turbines, hot section technology, structural mechanics codes, computational methods for dynamics, structural optimization, and applications of structural dynamics.

Lewis Structure Representation of Free Radicals Similar to ClO

ERIC Educational Resources Information Center

Hirsch, Warren; Kobrak, Mark

2007-01-01

The study describes the Lewis structure representation of various free radicals, which are quite similar to the ClO radical and its isoelectronic analogues. The analysis of the periodic trends of these radicals shows that oxygen is the most electronegative atom among them.

The Organization of Narrative Discourse in Lewy Body Spectrum Disorder

ERIC Educational Resources Information Center

Ash, Sharon; McMillan, Corey; Gross, Rachel G.; Cook, Philip; Morgan, Brianna; Boller, Ashley; Dreyfuss, Michael; Siderowf, Andrew; Grossman, Murray

2011-01-01

Narrative discourse is an essential component of day-to-day communication, but little is known about narrative in Lewy body spectrum disorder (LBSD), including Parkinson's disease (PD), Parkinson's disease with dementia (PDD), and dementia with Lewy bodies (DLB). We performed a detailed analysis of a semi-structured speech sample in 32 non-aphasic…

A study of how precursor key concepts for organic chemistry success are understood by general chemistry students

NASA Astrophysics Data System (ADS)

Meyer, Patrick Gerard

This study examines college student understanding of key concepts that will support future organic chemistry success as determined by university instructors. During four one-hour individual interviews the sixteen subjects attempted to solve general chemistry problems. A think-aloud protocol was used along with a whiteboard where the students could draw and illustrate their ideas. The protocols for the interviews were adapted from the Covalent Structure and Bonding two-tiered multiple choice diagnostic instrument (Peterson, Treagust, & Garnett, 1989) and augmented by the Geometry and Polarity of Molecules single-tiered multiple choice instrument (Furio & Calatayud, 1996). The interviews were videotaped, transcribed, and coded for analysis to determine the subjects' understanding of the key ideas. The subjects displayed many misconceptions that were summarized into nine assertions about student conceptualization of chemistry. (1) Many students misunderstand the location and nature of intermolecular forces. (2) Some think electronegativity differences among atoms in a molecule are sufficient to make the molecule polar, regardless of spatial arrangement. (3) Most know that higher phase change temperatures imply stronger intermolecular attractions, but many do not understand the difference between covalent molecular and covalent network substances. (4) Many have difficulty deciding whether a molecule is polar or non-polar, often confusing bilateral symmetry with spatial symmetry in all three dimensions. (5) Many cannot reliably draw correct Lewis structures due to carelessness and overuse of flawed algorithms. (6) Many are confused by how electrons can both repel one other and facilitate bonding between atoms via orbitals---this seems oxymoronic to them. (7) Many cannot explain why the atoms of certain elements do not follow the octet rule and some believe the octet rule alone can determine the shape of a molecule. (8) Most do know that electronegativity and polarity are not adequate to determine the shape of a molecule---but some apply the VSEPR theory in incorrect ways. (9) Students do not reason significantly differently when working with various representations of molecules such as ball-and-stick models, molecular formulas, and Lewis structures. The study illuminated specific parts of the general chemistry curriculum that are particularly troublesome for students but necessary for their further achievement in chemistry. This information is important; it gives the discipline of chemistry education target areas to focus on for general chemistry pedagogical improvement efforts.

Test facilities of the structural dynamics branch of NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Montague, Gerald T.; Kielb, Robert E.

1988-01-01

The NASA Lewis Research Center Structural Dynamics Branch conducts experimental and analytical research related to the structural dynamics of aerospace propulsion and power systems. The experimental testing facilities of the branch are examined. Presently there are 10 research rigs and 4 laboratories within the branch. These facilities are described along with current and past research work.

Writing-to-Learn the Nature of Science in the Context of the Lewis Dot Structure Model

ERIC Educational Resources Information Center

Shultz, Ginger V.; Gere, Anne Ruggles

2015-01-01

Traditional methods for teaching the Lewis dot structure model emphasize rule-based learning and often neglect the purpose and function of the model. Thus, many students are unable to extend their understanding of molecular structures in new contexts. The assignment described here addresses this issue by asking students to read and write about the…

Orbit Transfer Rocket Engine Technology Program. Task C.5. Enhanced Heat Transfer Combustor Technology

DTIC Science & Technology

1991-12-01

December, 1991 i--" NASA-Lewis Research Center Cleveland, Ohio 44135 94-08573 Contract No. NAS3-23773 .0l•!ill~• 111 l94 3 16 09V PISULATIXI NOTICI... 3 3.1 Test Hardware and Facility Description...V - Drawings and Layouts of Calorimeter Insert and Related Hardware .... 133 - Ui - FIGURES NUMBER PIALE GE 3 -1 Integrated Component Evaluator (I.C.E

Electronics technician Bill Clark assembling a cannon plug with the help of Jim Lewis

NASA Technical Reports Server (NTRS)

1991-01-01

There is always something needed for a NASA aircraft before a research flight can take place. This photo shows William J. Clark working on one of those 'somethings' while Jimmie C. Lewis watches ready to help. Working on a research project is a challenge, for there is no set pattern to follow. From the drawings to the final product there are many people who contribute to that final product -- the flight. The electronic technicians in the Instrumentation Laboratory at NASA Ames-Dryden Flight Research Facility are no exception. Bill Clark is busy creating a cannon plug to be used on the CV-990. He is soldering wires in the appropriate order so the plug will transmit electrical currents correctly when installed in the airplane. Jim stands by to give help and support on the project.

The Lewis thrust fault and related structures in the Disturbed Belt, northwestern Montana

USGS Publications Warehouse

Mudge, Melville Rhodes; Earhart, Robert L.

1980-01-01

The classical Lewis thrust fault in Glacier National Park has now been mapped 125 km south of the park to Steamboat Mountain, where the trace dies out in folded middle Paleozoic rocks. The known length of the fault is 452 km, extending northward from Steamboat Mountain to a point 225 km into Canada, where the fault also dies out in Paleozoic rocks. At the south end, the surface expression of the Lewis thrust begins in a shear zone in folded Mississippian rocks. To the north, the thrust progressively cuts downsection into Proterozoic Y (Belt) rocks near Glacier National Park. Displacement on the Lewis plate increases northward from approximately 3 km on an easterly trending hinge line at the West Fork of the Sun River to a postulated 65 km at the southern edge of the park, where the stratigraphic throw is about 6,500 m. Present data indicate the thrust formed during very late Paleocene to very early Eocene time. The Lewis thrust and related structures, the Hoadley thrust and the Continental Divide syncline, probably formed concurrently under the same stress field. The northern limit of the trace of the Hoadley thrust is within the lower portion of the Lewis plate, about 28 km north of where the Lewis thrust develops, and the Hoadley extends for at least 125 km to the south. Displacement of the Hoadley increases southward from about 1 km at the hinge line to an inferred 70 km near its known southern extent. If our inference is correct, the Hoadley is nearly the southern mirror image of the Lewis to the north. The Continental Divide syncline, a doubly plunging, broad, northerly trending open fold that is about 120 km long, is a major fold within the Lewis plate.

Lewis base activation of Lewis acids: catalytic, enantioselective addition of silyl ketene acetals to aldehydes.

PubMed

Denmark, Scott E; Beutner, Gregory L; Wynn, Thomas; Eastgate, Martin D

2005-03-23

The concept of Lewis base activation of Lewis acids has been reduced to practice for catalysis of the aldol reaction of silyl ketene acetals and silyl dienol ethers with aldehydes. The weakly acidic species, silicon tetrachloride (SiCl4), can be activated by binding of a strongly Lewis basic chiral phosphoramide, leading to in situ formation of a chiral Lewis acid. This species has proven to be a competent catalyst for the aldol addition of acetate-, propanoate-, and isobutyrate-derived silyl ketene acetals to conjugated and nonconjugated aldehydes. Furthermore, vinylogous aldol reactions of silyl dienol ethers are also demonstrated. The high levels of regio-, anti diastereo-, and enantioselectivity observed in these reactions can be rationalized through consideration of an open transition structure where steric interactions between the silyl cation complex and the approaching nucleophile are dominant.

Lewy and his inclusion bodies: Discovery and rejection.

PubMed

Engelhardt, Eliasz; Gomes, Marleide da Mota

2017-01-01

Fritz Jacob Heinrich Lewy described the pathology of Paralysis agitans [Parkinson disease] and was the first to identify eosinophilic inclusion bodies in neurons of certain brain nuclei, later known as Lewy bodies, the pathological signature of the Lewy body diseases. In 1912, he published his seminal study, followed soon after by an update paper, and 10 years later, in 1923, by his voluminous book, where he exhaustively described the subject. The publication provided extensive information on the pathology of Paralysis agitans, and the entirely novel finding of eosinophilic inclusion bodies, which would become widely recognized and debated in the future. His discovery was acknowledged by important researchers who even named the structure after him. However, after his last publication on the issue, inexplicably, he never mentioned his histopathological discovery again. Despite several hypotheses, the reasons that led him to neglect (reject) the structure which he so preeminently described have remained elusive.

Mitochondrial dynamics in Parkinson's disease: a role for α-synuclein?

PubMed Central

Pozo Devoto, Victorio M.

2017-01-01

ABSTRACT The distinctive pathological hallmarks of Parkinson's disease are the progressive death of dopaminergic neurons and the intracellular accumulation of Lewy bodies enriched in α-synuclein protein. Several lines of evidence from the study of sporadic, familial and pharmacologically induced forms of human Parkinson's disease also suggest that mitochondrial dysfunction plays an important role in disease progression. Although many functions have been proposed for α-synuclein, emerging data from human and animal models of Parkinson's disease highlight a role for α-synuclein in the control of neuronal mitochondrial dynamics. Here, we review the α-synuclein structural, biophysical and biochemical properties that influence relevant mitochondrial dynamic processes such as fusion-fission, transport and clearance. Drawing on current evidence, we propose that α-synuclein contributes to the mitochondrial defects that are associated with the pathology of this common and progressive neurodegenerative disease. PMID:28883016

Mitochondrial dynamics in Parkinson's disease: a role for α-synuclein?

PubMed

Pozo Devoto, Victorio M; Falzone, Tomas L

2017-09-01

The distinctive pathological hallmarks of Parkinson's disease are the progressive death of dopaminergic neurons and the intracellular accumulation of Lewy bodies enriched in α-synuclein protein. Several lines of evidence from the study of sporadic, familial and pharmacologically induced forms of human Parkinson's disease also suggest that mitochondrial dysfunction plays an important role in disease progression. Although many functions have been proposed for α-synuclein, emerging data from human and animal models of Parkinson's disease highlight a role for α-synuclein in the control of neuronal mitochondrial dynamics. Here, we review the α-synuclein structural, biophysical and biochemical properties that influence relevant mitochondrial dynamic processes such as fusion-fission, transport and clearance. Drawing on current evidence, we propose that α-synuclein contributes to the mitochondrial defects that are associated with the pathology of this common and progressive neurodegenerative disease. © 2017. Published by The Company of Biologists Ltd.

Manipulating the Lewis antigen specificity of the cholesterol-dependent cytolysin lectinolysin

PubMed Central

Lawrence, Sara L.; Feil, Susanne C.; Holien, Jessica K.; Kuiper, Michael J.; Doughty, Larissa; Dolezal, Olan; Mulhern, Terrence D.; Tweten, Rodney K.; Parker, Michael W.

2012-01-01

The cholesterol-dependent cytolysins (CDCs) attack cells by punching large holes in their membranes. Lectinolysin from Streptococcus mitis is unique among CDCs due to the presence of an N-terminal lectin domain that enhances the pore-forming activity of the toxin. We recently determined the crystal structures of the lectin domain in complex with various glycans. These structures revealed the molecular basis for the Lewis antigen specificity of the toxin. Based on this information we have used in silico molecular modeling to design a mutant toxin, which we predicted would increase its specificity for Lewis y, an antigen found on the surface of cancer cells. Surprisingly, we found by surface plasmon resonance binding experiments that the resultant mutant lectin domain exhibited higher specificity for Lewis b antigens instead. We then undertook comparative crystallographic and molecular dynamics simulation studies of the wild-type and mutant lectin domains to understand the molecular basis for the disparity between the theoretical and experimental results. The crystallographic results revealed that the net number of interactions between Lewis y and wild-type versus mutant was unchanged whereas there was a loss of a hydrogen bond between mutant and Lewis b compared to wild-type. In contrast, the molecular dynamics studies revealed that the Lewis b antigen spent more time in the binding pocket of the mutant compared to wild-type and the reverse was true for Lewis y. The results of these simulation studies are consistent with the conclusions drawn from the surface plasmon resonance studies. This work is part of a program to engineer lectinolysin so that it will target and kill specific cells in human diseases. PMID:23181061

Lewis Structures Technology, 1988. Volume 2: Structural Mechanics

NASA Technical Reports Server (NTRS)

1988-01-01

Lewis Structures Div. performs and disseminates results of research conducted in support of aerospace engine structures. These results have a wide range of applicability to practitioners of structural engineering mechanics beyond the aerospace arena. The engineering community was familiarized with the depth and range of research performed by the division and its academic and industrial partners. Sessions covered vibration control, fracture mechanics, ceramic component reliability, parallel computing, nondestructive evaluation, constitutive models and experimental capabilities, dynamic systems, fatigue and damage, wind turbines, hot section technology (HOST), aeroelasticity, structural mechanics codes, computational methods for dynamics, structural optimization, and applications of structural dynamics, and structural mechanics computer codes.

Student construction of small molecule models using Spartan Model to explore polarity

NASA Astrophysics Data System (ADS)

Dale, Glenn Lamar

2006-12-01

This study compared the attitudes and the gains of knowledge concerning Lewis structures and polarity of molecules. The students performed a lab exercise in which they drew Lewis structures, constructed models of the molecules, determined the geometry of the molecules, and determined the polarity of the molecules. The control group students constructed models using physical ball-and-stick models. The treatment group students used Spartan Model to construct models. Students from a university and a community college participated in this study. Four lab classes at each school made up the treatment group. Five lab classes at the university and three lab classes at the community college made up the control group. The treatment group classes were selected based on available computer resources. All students in the study were given the Lab Pre Test, Lab Post Test, and the Lecture Post Test to assess the student's ability to answer questions pertaining to Lewis structures and polarity of molecules. An Attitudinal Survey assessed the attitudes of the students who participated in the study. Student interviews were performed to assess the student's attitudes towards the lab exercise. The interviews investigated attitudes about the modeling exercise, Lewis structures, and polarity of molecules. There were no significant differences in the performance of the treatment group when compared to the control group on the performance assessment instruments at the university or the community college. The treatment group students at the university had a more positive attitude about the lab activity. They believed that the lab activity helped them better understand the concepts of Lewis structure and molecular polarity. At the community college, the control group students had a more positive attitude about the lab activity. The students involved in the study believed that the lab activity helped them to understand the concepts of molecular geometry and polarity. The interviews of the treatment group students indicated that they strongly believed that the lab activity helped them better understand the concept of Lewis structures and of molecular polarity. As reflected in the interviews of the treatment group and the control group, the lab activity did not help the students be able to look at a Lewis structure and build a mental image of the molecule. The students believed the electrostatic potential plots generated by Spartan Model were very insightful into the concept of polarity. It gave them a visual representation of a difficult topic.

The NASA Lewis Research Center High Temperature Fatigue and Structures Laboratory

NASA Technical Reports Server (NTRS)

Mcgaw, M. A.; Bartolotta, P. A.

1987-01-01

The physical organization of the NASA Lewis Research Center High Temperature Fatigue and Structures Laboratory is described. Particular attention is given to uniaxial test systems, high cycle/low cycle testing systems, axial torsional test systems, computer system capabilities, and a laboratory addition. The proposed addition will double the floor area of the present laboratory and will be equipped with its own control room.

HBCUs Research Conference Agenda and Abstracts

NASA Technical Reports Server (NTRS)

Dutta, Sunil (Compiler)

1997-01-01

The purpose of this Historically Black Colleges and Universities (HBCUS) Research Conference was to provide an opportunity for principal investigators and their students to present research progress reports. The abstracts included in this report indicate the range and quality of research topics such as aeropropulsion, space propulsion, space power, fluid dynamics, designs, structures and materials being funded through grants from Lewis Research Center to HBCUS. The conference generated extensive networking between students, principal investigators, Lewis technical monitors, and other Lewis researchers.

HBCUs Research Conference Agenda and Abstracts

NASA Technical Reports Server (NTRS)

Dutta, Sunil (Compiler)

1998-01-01

The purpose of this Historically Black Colleges and Universities (HBCUs) Research Conference was to provide an opportunity for principal investigators and their students to present research progress reports. The abstracts included in this report indicate the range and quality of research topics such as aeropropulsion, space propulsion, space power, fluid dynamics, designs, structures and materials being funded through grants from Lewis Research Center to HBCUs. The conference generated extensive networking between students, principal investigators, Lewis technical monitors, and other Lewis researchers.

HBCUs Research Conference agenda and abstracts

NASA Technical Reports Server (NTRS)

Dutta, Sunil (Compiler)

1995-01-01

The purpose of this Historically Black Colleges and Universities (HBCUs) Research conference was to provide an opportunity for principal investigators and their students to present research progress reports. The abstracts included in this report indicate the range and quality of research topics such as aeropropulsion, space propulsion, space power, fluid dynamics, designs, structures and materials being funded through grants from Lewis Research Center to HBCUs. The conference generated extensive networking between students, principal investigators, Lewis technical monitors, and other Lewis researchers.

Natural killer cells attack tumor cells expressing high levels of sialyl Lewis x oligosaccharides

PubMed Central

Ohyama, Chikara; Kanto, Satoru; Kato, Kazunori; Nakano, Osamu; Arai, Yoichi; Kato, Tetsuro; Chen, Shihao; Fukuda, Michiko N.; Fukuda, Minoru

2002-01-01

Epithelial carcinoma and leukemia cells express sialyl Lewis x oligosaccharides as tumor-associated carbohydrate antigens. To determine the role of sialyl Lewis x oligosaccharides in tumor dissemination, human melanoma MeWo cells, which do not express sialyl Lewis x, were transfected with α1,3-fucosyltransferase III (FTIII), and cell lines expressing different amounts of sialyl Lewis x were isolated. When these cells were injected into the tail vein of nude mice, cells expressing moderate amounts of sialyl Lewis x (MeWo-FTIII⋅M) produced a significantly greater number of lung tumor foci than did parental MeWo cells. In contrast, cells expressing large amounts of sialyl Lewis x (MeWo-FTIII⋅H) produced few lung tumor foci in nude mice but were highly tumorigenic in beige mice, which have defective natural killer (NK) cells. In vitro assays demonstrated that MeWo-FTIII⋅H cells are much more sensitive to NK cell-mediated cytotoxicity than are MeWo-FTIII⋅M cells or parental MeWo cells and the susceptibility of MeWo-FTIII⋅H cells to NK cell-mediated cytolysis can be inhibited by preincubating MeWo-FTIII⋅H cells with anti-sialyl Lewis x antibody. Moreover, we discovered that NK cell-mediated cytolysis of MeWo-FTIII⋅H cells can be inhibited by the addition of an antibody against the NK cell receptor CD94 or sialyl Lewis x oligosaccharides. These results, combined with structural analysis of MeWo-FTIII⋅H cell carbohydrates, indicate that moderate amounts of sialyl Lewis x lead to tumor metastasis, whereas expression of high levels of sialyl Lewis x leads to an NK cell attack on tumor cells, demonstrating that expression of different amounts of sialyl Lewis x results in entirely different biological consequences. PMID:12370411

Reduction of CO 2 to methanol using aluminum ester FLPs

DOE PAGES

Smythe, Nathan C.; Dixon, David A.; Garner, III, Edward B.; ...

2015-10-09

Herein we report the synthesis of Al-based esters containing halogenated benzene rings. These Lewis acids were paired with phosphines to form frustrated Lewis pairs (FLPs) which could subsequently bind CO 2. While these FLPs were not sufficiently water-stable to catalyze the reduction of CO 2 to MeOH using NH 3BH 3 as the reductant, we examine the effect of varying Lewis acid strength. Frustrated Lewis pairs (FLPs) are combinations of Lewis acids and Lewis bases where the acid and base are either sterically or geometrically restricted from interacting as strongly as their electronic structures would allow. This effect leads tomore » enhanced reactivity towards small molecules and, consequently, interest in their potential as metal-free catalysts [1], [2], [3], [4] and [5]. Furthermore, to-date, the biggest success has been based around the ability of a myriad of systems to heterolytically cleave H 2 and perform catalytic hydrogenations [2] and [3].« less

Research and technology highlights of the Lewis Research Center

NASA Technical Reports Server (NTRS)

1984-01-01

Highlights of research accomplishments of the Lewis Research Center for fiscal year 1984 are presented. The report is divided into four major sections covering aeronautics, space communications, space technology, and materials and structures. Six articles on energy are included in the space technology section.

Synthesis, characterization, and application of two Al(OR(F))3 Lewis superacids.

PubMed

Kraft, Anne; Trapp, Nils; Himmel, Daniel; Böhrer, Hannes; Schlüter, Peter; Scherer, Harald; Krossing, Ingo

2012-07-23

We report herein the synthesis and full characterization of the donor-free Lewis superacids Al(OR(F))(3) with OR(F) = OC(CF(3))(3) (1) and OC(C(5)F(10))C(6)F(5) (2), the stabilization of 1 as adducts with the very weak Lewis bases PhF, 1,2-F(2)C(6)H(4), and SO(2), as well as the internal C-F activation pathway of 1 leading to Al(2)(F)(OR(F))(5) (4) and trimeric [FAl(OR(F))(2)](3) (5, OR(F) = OC(CF(3))(3)). Insights have been gained from NMR studies, single-crystal structure determinations, and DFT calculations. The usefulness of these Lewis acids for halide abstractions has been demonstrated by reactions with trityl chloride (NMR; crystal structures). The trityl salts allow the introduction of new, heteroleptic weakly coordinating [Cl-Al(OR(F))(3)](-) anions, for example, by hydride or alkyl abstraction reactions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrated analysis of engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1981-01-01

The need for light, durable, fuel efficient, cost effective aircraft requires the development of engine structures which are flexible, made from advaced materials (including composites), resist higher temperatures, maintain tighter clearances and have lower maintenance costs. The formal quantification of any or several of these requires integrated computer programs (multilevel and/or interdisciplinary analysis programs interconnected) for engine structural analysis/design. Several integrated analysis computer prorams are under development at Lewis Reseach Center. These programs include: (1) COBSTRAN-Composite Blade Structural Analysis, (2) CODSTRAN-Composite Durability Structural Analysis, (3) CISTRAN-Composite Impact Structural Analysis, (4) STAEBL-StruTailoring of Engine Blades, and (5) ESMOSS-Engine Structures Modeling Software System. Three other related programs, developed under Lewis sponsorship, are described.

Structural Optimization Methodology for Rotating Disks of Aircraft Engines

NASA Technical Reports Server (NTRS)

Armand, Sasan C.

1995-01-01

In support of the preliminary evaluation of various engine technologies, a methodology has been developed for structurally designing the rotating disks of an aircraft engine. The structural design methodology, along with a previously derived methodology for predicting low-cycle fatigue life, was implemented in a computer program. An interface computer program was also developed that gathers the required data from a flowpath analysis program (WATE) being used at NASA Lewis. The computer program developed for this study requires minimum interaction with the user, thus allowing engineers with varying backgrounds in aeropropulsion to successfully execute it. The stress analysis portion of the methodology and the computer program were verified by employing the finite element analysis method. The 10th- stage, high-pressure-compressor disk of the Energy Efficient Engine Program (E3) engine was used to verify the stress analysis; the differences between the stresses and displacements obtained from the computer program developed for this study and from the finite element analysis were all below 3 percent for the problem solved. The computer program developed for this study was employed to structurally optimize the rotating disks of the E3 high-pressure compressor. The rotating disks designed by the computer program in this study were approximately 26 percent lighter than calculated from the E3 drawings. The methodology is presented herein.

Expression of Simple Mucin Type Antigens and Lewis Type 1 and Type 2 Chain Antigens in the Thyroid Gland: An Immunohistochemical Study of Normal Thyroid Tissues, Benign Lesions, and Malignant Tumors.

PubMed

Fonseca, Elsa; Castanhas, Salome; Sobrinho-Simoes, Manuel

1996-01-01

In order to characterize the pattern of expression of carbohydrate structures in several types of thyroid tissues and to evaluate the putative usefulness of the detection of such antigens in diagnostic surgical pathology, we undertook the immunohistochemical study of simple mucin type antigens (T, Tn, and sialyl Tn), Lewis type I antigens (Lewis a, sialyl Lewis a, and Lewis b), and Lewis type 2 related antigens (precursor type 2, H type 2, Lewis x, sialyl Lewis x, and Lewis y) in thyroid samples obtained from 65 patients. The material consisted on paraffin sections of normal thyroid (n = 43), benign lesions (13 goiters/hyperplastic lesions and 15 adenomas), and malignant tumors (12 follicular carcinomas and 27 papillary carcinomas, 5 of which had lymph node metastases) of the thyroid follicular epithelium. Tn, T, and precursor type 2 antigens were the only antigens that were detected and very rarely in normal thyroid. Benign lesions were similar to normal thyroid despite displaying a higher prevalence of immunoreactivity for several antigens of the three groups. Thyroid carcinomas presented a significantly higher level of expression of all types of simple mucin, Lewis type 1, and Lewis type 2 antigens than the normal thyroid and benign lesions. The expression of sialyl Tn was restricted to malignant tumors, and the expression of sialyl Lewis x was closely associated, though not exclusively, to papillary carcinomas. The immunoreactivity was stronger and the number of positive cases was higher in papillary than in follicular carcinomas. No differences were found between primary tumors and the respective metastases. The existence of distinct patterns of expression of carbohydrate antigens in different types of thyroid lesions points to the usefulness of the detection of some of these antigens in thyroid surgical pathology. The putative role of such antigens in the peculiar metastatic properties of thyroid carcinomas remains unsettled.

Synergistic effects of Lewis bases and substituents on the electronic structure and reactivity of boryl radicals.

PubMed

Lu, Dongmei; Wu, Chao; Li, Pengfei

2014-02-03

Boryl radicals have the potential for the development of new molecular entities and for application in new radical reactions. However, the effects of the substituents and coordinating Lewis bases on the reactivity of boryl radicals are not fully understood. By using first-principles methods, we investigated the spin-density distribution and reactivity of a series of boryl radicals with various substituents and Lewis bases. The substituents, along with the Lewis bases, only affect the radical reactivity when an unpaired electron is in the boron pz orbital, that is, for three-coordinate radicals. We found evidence of synergistic effects between the substituents and the Lewis bases that can substantially broaden the tunability of the reactivity of the boryl radicals. Among Lewis bases, pyridine and imidazol-2-ylidene show a similar capacity for stabilization by delocalizing the spin density. Electron-donating substituents, such as nitrogen, more efficiently stabilize boryl radicals than oxygen and carbon atoms. The reactivity of a boryl radical is always boron based, irrespective of the spin density on boron. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Engine structures: A bibliography of Lewis Research Center's research for 1980-1987

NASA Technical Reports Server (NTRS)

1988-01-01

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Structures Division of the NASA Lewis Research Center from 1980 through 1987. All the publications were announced in the l980 to 1987 issues of STAR (Scientific and Technical Aerospace Reports) and or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses.

Driving Competence in Mild Dementia with Lewy Bodies: In Search of Cognitive Predictors Using Driving Simulation

PubMed Central

Yamin, Stephanie; Stinchcombe, Arne; Gagnon, Sylvain

2015-01-01

Driving is a multifactorial behaviour drawing on multiple cognitive, sensory, and physical systems. Dementia is a progressive and degenerative neurological condition that impacts the cognitive processes necessary for safe driving. While a number of studies have examined driving among individuals with Alzheimer's disease, less is known about the impact of Dementia with Lewy Bodies (DLB) on driving safety. The present study compared simulated driving performance of 15 older drivers with mild DLB with that of 21 neurologically healthy control drivers. DLB drivers showed poorer performance on all indicators of simulated driving including an increased number of collisions in the simulator and poorer composite indicators of overall driving performance. A measure of global cognitive function (i.e., the Mini Mental State Exam) was found to be related to the overall driving performance. In addition, measures of attention (i.e., Useful Field of View, UFOV) and space processing (Visual Object and Space Perception, VOSP, Test) correlated significantly with a rater's assessment of driving performance. PMID:26713169

Playing around in Lewis Carroll's "Alice" Books

ERIC Educational Resources Information Center

Susina, Jan

2010-01-01

Mathematician Charles Dodgson's love of play and his need for rules came together in his use of popular games as part of the structure of the two famous children's books, "Alice in Wonderland" and "Through the Looking-Glass," he wrote under the pseudonym Lewis Carroll. The author of this article looks at the interplay between…

NASA LeRC/Akron University Graduate Cooperative Fellowship Program and Graduate Student Researchers Program

NASA Technical Reports Server (NTRS)

Fertis, D. G.

1983-01-01

On June 1, 1980, the University of Akron and the NASA Lewis Research Center (LERC) established a Graduate Cooperative Fellowship Program in the specialized areas of Engine Structural Analysis and Dynamics, Computational Mechanics, Mechanics of Composite Materials, and Structural Optimization, in order to promote and develop requisite technologies in these areas of engine technology. The objectives of this program are consistent with those of the NASA Engine Structure Program in which graduate students of the University of Akron participate by conducting research at Lewis. This report is the second on this grant and summarizes the second and third year research effort, which includes the participation of five graduate students where each student selects one of the above areas as his special field of interest. Each student is required to spend 30 percent of his educational training time at the NASA Lewis Research Center and the balance at the University of Akron. His course work is judiciously selected and tailored to prepare him for research work in his field of interest. A research topic is selected for each student while in residence at the NASA Lewis Research Center, which is also approved by the faculty of the University of Akron as his thesis topic for a Master's and/or a Ph.D. degree.

NASA Aircraft in the Hangar at Lewis Research Center

NASA Image and Video Library

1970-09-21

Several aircraft parked inside the Flight Research Building, or hangar, at the National Aeronautics and Space Administration (NASA) Lewis Research Center in Cleveland, Ohio. A Convair F-106B Delta Dart is in the foreground, a Convair F-102A Delta Dagger is to the right, a Douglas DC-3 is in the back to left, and a Convair T-29 is in background. Lewis’ Martin B-57B Canberra is not seen in this photograph. The F-102A had just been acquired by Lewis to serve as a chase plane for the F-106B. The Lewis team removed the weapons system and 700 pounds of wire from the F-106B when it was acquired on October 20, 1966. The staff cut holes in the wings and modified the elevons to mount the test nacelles. A 228-gallon fuel tank was installed in the missile bay, and the existing wing tanks were used for instrumentation. This photograph contains a rare view of the Block House, seen to the left of the aircraft. Lewis acquired three large developmental programs in 1962—the Centaur and Agena rockets and the M-1 engine. The center was short on office space at the time, and its flight research program was temporarily on the wane. Lewis management decided to construct a large cinderblock structure inside one half of the hangar to house the new personnel. This structure was used until 1965 when the new Developmental Engineering Building was built. The Block House was eventually torn down in 1973.

Ambiphilic Frustrated Lewis Pair Exhibiting High Robustness and Reversible Water Activation: Towards the Metal-Free Hydrogenation of Carbon Dioxide.

PubMed

Rochette, Étienne; Courtemanche, Marc-André; Pulis, Alexander P; Bi, Wenhua; Fontaine, Frédéric-Georges

2015-06-29

The synthesis and structural characterization of a phenylene-bridged Frustrated Lewis Pair (FLP) having a 2,2,6,6‑tetramethylpiperidine (TMP) as the Lewis base and a 9-borabicyclo[3.3.1]nonane (BBN) as the Lewis acid is reported. This FLP exhibits unique robustness towards the products of carbon dioxide hydrogenation. The compound shows reversible splitting of water, formic acid and methanol while no reaction is observed in the presence of excess formaldehyde. The molecule is incredibly robust, showing little sign of degradation after heating at 80 °C in benzene with 10 equiv. of formic acid for 24 h. The robustness of the system could be exploited in the design of metal-free catalysts for the hydrogenation of carbon dioxide.

Despin System for Hydrogen Tank in the Propulsion Systems Laboratory

NASA Image and Video Library

1962-04-21

Mechanic Howard Wine inspects the setup of a spin isolator in Cell 2 of the Propulsion Systems Laboratory at the National Aeronautics and Space Administration (NASA) Lewis Research Center. Photographer Al Jecko filmed the proceedings. This test was unique in that the chamber’s altitude system was used, but not its inlet air flow. The test was in preparation for an upcoming launch of modified liquid hydrogen propellant tank on a sounding rocket. This Weightlessness Analysis Sounding Probe (WASP) was part of Lewis investigation into methods for controlling partially filled liquid hydrogen fuel tanks during flight. Second-stage rockets, the Centaur in particular, were designed to stop their engines and coast, then restart them when needed. During this coast period, the propellant often shifted inside the tank. This movement could throw the rocket off course or result in the sloshing of fuel away from the fuel pump. Wine was one of only three journeymen mechanics at Lewis when he was hired in January 1954. He spent his first decade in the Propulsion Systems Laboratory and was soon named a section head. Wine went on to serve as Assistant Division Chief and later served as an assistant to the director. Jecko joined the center in 1947 as a photographer and artist. He studied at the Cleveland School or Art and was known for his cartoon drawing. He worked at the center for 26 years.

Aerospace applications of PMR polyimide composites

NASA Technical Reports Server (NTRS)

Serafini, T. T.

1985-01-01

The current status of the novel class of processable, addition-type polyimides known as PMR (for in situ polymerization of monomer reactants) polyimides, developed by NASA at the Lewis Research Center, is reviewed. Highlights of PMR technology studies conducted at NASA Lewis are presented. Several examples of industrial applications of PMR-15 polyimide composites to aerospace structural components are examined.

The Lewis superacid Al[N(C6F5)2]3 and its higher homolog Ga[N(C6F5)2]3 – structural features, theoretical investigation and reactions of a metal amide with higher fluoride ion affinity than SbF5† †Electronic supplementary information (ESI) available. CCDC 1557072–1557076. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc03988c

PubMed Central

Kögel, J. F.; Sorokin, D. A.; Khvorost, A.; Scott, M.; Harms, K.; Himmel, D.; Krossing, I.

2017-01-01

Herein we present the synthesis of the two Lewis acids Al[N(C6F5)2]3 (ALTA) and Ga[N(C6F5)2]3 (GATA) via salt elimination reactions. The metal complexes were characterized by NMR-spectroscopic methods and X-ray diffraction analysis revealing the stabilization of the highly Lewis acidic metal centers by secondary metal–fluorine contacts. The Lewis acidic properties of Al[N(C6F5)2]3 and Ga[N(C6F5)2]3 are demonstrated by reactions with Lewis bases resulting in the formation of metallates accompanied by crucial structural changes. The two metallates [Cs(Tol)3]+[FAl(N(C6F5)2)3]– and [AsPh4]+[ClGa(N(C6F5)2)3]– contain interesting weakly coordinating anions. The reaction of Al[N(C6F5)2]3 with trityl fluoride yielded [CPh3]+[FAl(N(C6F5)2)3]– which could find application in the activation of metallocene polymerization catalysts. The qualitative Lewis acidity of Al[N(C6F5)2]3 and Ga[N(C6F5)2]3 was investigated by means of competition experiments for chloride ions in solution. DFT calculations yielded fluoride ion affinities in the gas phase (FIA) of 555 kJ mol–1 for Al[N(C6F5)2]3 and 472 kJ mol–1 for Ga[N(C6F5)2]3. Thus, Al[N(C6F5)2]3 can be considered a Lewis superacid with a fluoride affinity higher than SbF5 (493 kJ mol–1) whereas the FIA of the corresponding gallium complex is slightly below the threshold to Lewis superacidity. PMID:29629094

Thioarsenides: A case for long-range Lewis acid-base-directed van der Waals interactions

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

Gibbs, Gerald V.; Wallace, Adam F.; Downs, R. T.

2011-04-01

Electron density distributions, bond paths, Laplacian and local energy density properties have been calculated for a number of As4Sn (n = 3,4,5) thioarsenide molecular crystals. On the basis of the distributions, the intramolecular As-S and As-As interactions classify as shared bonded interactions and the intermolecular As-S, As-As and S-S interactions classify as closed-shell van der Waals bonded interactions. The bulk of the intermolecular As-S bond paths link regions of locally concentrated electron density (Lewis base regions) with aligned regions of locally depleted electron density (Lewis acid regions) on adjacent molecules. The paths are comparable with intermolecular paths reported for severalmore » other molecular crystals that link aligned Lewis base and acid regions in a key-lock fashion, interactions that classified as long range Lewis acid-base directed van der Waals interactions. As the bulk of the intermolecular As-S bond paths (~70%) link Lewis acid-base regions on adjacent molecules, it appears that molecules adopt an arrangement that maximizes the number of As-S Lewis acid-base intermolecular bonded interactions. The maximization of the number of Lewis acid-base interactions appears to be connected with the close-packed array adopted by molecules: distorted cubic close-packed arrays are adopted for alacránite, pararealgar, uzonite, realgar and β-AsS and the distorted hexagonal close-packed arrays adopted by α- and β-dimorphite. A growth mechanism is proposed for thioarsenide molecular crystals from aqueous species that maximizes the number of long range Lewis acid-base vdW As-S bonded interactions with the resulting directed bond paths structuralizing the molecules as a molecular crystal.« less

Computational structural mechanics engine structures computational simulator

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1989-01-01

The Computational Structural Mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures.

Quantitative determination of oxygen defects, surface lewis acidity, and catalytic properties of mesoporous MoO3/SBA-15 catalysts

NASA Astrophysics Data System (ADS)

González, Julio; Wang, Jin An; Chen, Lifang; Manríquez, Maria; Salmones, José; Limas, Roberto; Arellano, Ulises

2018-07-01

A set of MoO3/SBA-15 mesoporous catalysts were characterized with a variety of spectroscopic techniques and their crystalline structures were refined with Rietveld method. Oxygen defect concentration, crystallite size, phase composition, surface acidity, mesoporous regularity, and textural properties were reported. Both α-MoO3 and β-MoO3 phases coexisted but α-MoO3 was predominated. Oxygen defects were created in the orthorhombic structure and its concentration decreased from 3.08% for the 20 wt%MoO3/SBA-15 to 0.55% for the 25 wt%MoO3/SBA-15. All the MoO3/SBA-15 catalysts chiefly contained a big number of Lewis acid sites originating from oxygen defects in MoO3 crystals. In the absence of formic acid, the oxidation of 4,6-dibenzothiophene (4,6-DMDBT) in a model diesel was almost proportional to the number of Lewis acid sites. In the presence of formic acid, 4,6-DMDBT oxidation was significantly affected by the formation of surface peroxometallic complex and Lewis acidity. Formic acid addition could improve the ODS efficiency by promoting peroxometallic complex formation and enhancing oxidant stability. Under the optimal reaction condition using the best 15 and 20 wt%MoO3/SBA-15 catalysts, more than 99% 4,6-DMDBT could be removed at 70 °C within 30 min. This work confirmed that 4,6-DMDBT oxidation is a texture and particle size sensitive and Lewis acidity dependent reaction. This work also shows that crystalline structure refinement combination with experiments can gain new insights in the design of heterogeneous nanocatalysts and help to better understand the catalytic behavior in the oxidative desulfurization reactions.

A Heterogeneous Metal-Free Catalyst for Hydrogenation: Lewis Acid-Base Pairs Integrated into a Carbon Lattice.

PubMed

Ding, Yuxiao; Huang, Xing; Yi, Xianfeng; Qiao, Yunxiang; Sun, Xiaoyan; Zheng, Anmin; Su, Dang Sheng

2018-06-04

Designing heterogeneous metal-free catalysts for hydrogenation is a long-standing challenge in catalysis. Nanodiamond-based carbon materials were prepared that are surface-doped with electron-rich nitrogen and electron-deficient boron. The two heteroatoms are directly bonded to each other to form unquenched Lewis pairs with infinite π-electron donation from the surrounding graphitic structure. Remarkably, these Lewis pairs can split H 2 to form H + /H - pairs, which subsequently serve as the active species for hydrogenation of different substrates. This unprecedented finding sheds light on the uptake of H 2 across carbon-based materials and suggests that dual Lewis acidity-basicity on the carbon surface may be used to heterogeneously activate a variety of small molecules. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

NASA Lewis Helps Develop Advanced Saw Blades for the Lumber Industry

NASA Technical Reports Server (NTRS)

1998-01-01

NASA Lewis Research Center's Structures and Material Divisions are centers of excellence in high-temperature alloys for aerospace applications such as advanced aircraft and rocket engines. Lewis' expertise in these fields was enlisted in the development of a new generation of circular sawblades for the lumber industry to use in cutting logs into boards. The U.S. Department of Agriculture's (USDA) Forest Products Laboratory and their supplier had succeeded in developing a thinner sawblade by using a nickel-based alloy, but they needed to reduce excessive warping due to residual stresses. They requested assistance from Lewis' experts, who successfully eliminated the residual stress problem and increased blade strength by over 12 percent. They achieved this by developing an innovative heat treatment based on their knowledge of nickel-based superalloys used in aeropropulsion applications.

Composites research at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Levine, Stanley R.; Duffy, Stephen; Vary, Alex; Nathal, Michael V.; Miner, Robert V.; Arnold, Steven M.; Castelli, Michael G.; Hopkins, Dale A.; Meador, Michael A.

1994-01-01

Composites research at NASA Lewis is focused on their applications in aircraft propulsion, space propulsion, and space power, with the first being predominant. Research on polymer-, metal-, and ceramic-matrix composites is being carried out from an integrated materials and structures viewpoint. This paper outlines some of the topics being pursued from the standpoint of key technical issues, current status, and future directions.

The Lewis Electron-Pair Model, Spectroscopy, and the Role of the Orbital Picture in Describing the Electronic Sructure of Molecules.

ERIC Educational Resources Information Center

Gallup, G. A.

1988-01-01

Describes why specific forms of orbitals used to interpret spectroscopy involving electronic transitions may not say much about the electronic structure of molecules. Discusses several theoretical approaches to explain the anomoly. Determines that the Lewis electron-pair model for molecules is a good predictor of spectroscopic results. (ML)

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

Nelson, Nicholas C.; Wang, Zhuoran; Naik, Pranjali

Deposition of trimethylphosphate onto ceria followed by thermal treatment resulted in the formation of surface phosphates with retention of the ceria fluorite structure. The structural and chemical properties of the phosphate-functionalized ceria were studied using 31P solid-state NMR, XPS, zeta titration, ammonia thermal desorption, pyridine adsorption, and model reactions. The introduction of phosphates generated Brønsted acid sites and decreased the number of Lewis acid sites on the surface. The relative amount of Lewis and Brønsted acids can be controlled by the amount of trimethylphosphate used in the synthesis. Upon deposition of Pd, the multifunctional material showed enhanced activity for themore » hydrogenolysis of eugenol and guaiacol compared to Pd on the unmodified ceria support. As a result, this was attributed to the cooperativity between the Lewis acid sites, which activate the substrate for dearomatization, and the redox/Brønsted acid properties, which catalyze hydrogenolysis.« less

Masking of Lewis acidity trends in the solid-state structures of trichlorido- and tribromido(2,2':6',2''-terpyridine-κ(3)N,N',N'')gallium(III).

PubMed

Kazakov, Igor V; Bodensteiner, Michael; Timoshkin, Alexey Y

2014-03-01

The molecular structures of trichlorido(2,2':6',2''-terpyridine-κ(3)N,N',N'')gallium(III), [GaCl3(C15H11N3)], and tribromido(2,2':6',2''-terpyridine-κ(3)N,N',N'')gallium(III), [GaBr3(C15H11N3)], are isostructural, with the Ga(III) atom displaying an octahedral geometry. It is shown that the Ga-N distances in the two complexes are the same within experimental error, in contrast to expected bond lengthening in the bromide complex due to the lower Lewis acidity of GaBr3. Thus, masking of the Lewis acidity trends in the solid state is observed not only for complexes of group 13 metal halides with monodentate ligands but for complexes with the polydentate 2,2':6',2''-terpyridine donor as well.

Synthesis, structure and reaction chemistry of a nucleophilic aluminyl anion.

PubMed

Hicks, Jamie; Vasko, Petra; Goicoechea, Jose M; Aldridge, Simon

2018-05-01

The reactivity of aluminium compounds is dominated by their electron deficiency and consequent electrophilicity; these compounds are archetypal Lewis acids (electron-pair acceptors). The main industrial roles of aluminium, and classical methods of synthesizing aluminium-element bonds (for example, hydroalumination and metathesis), draw on the electron deficiency of species of the type AlR 3 and AlCl 3 1,2 . Whereas aluminates, [AlR 4 ] - , are well known, the idea of reversing polarity and using an aluminium reagent as the nucleophilic partner in bond-forming substitution reactions is unprecedented, owing to the fact that low-valent aluminium anions analogous to nitrogen-, carbon- and boron-centred reagents of the types [NX 2 ] - , [CX 3 ] - and [BX 2 ] - are unknown 3-5 . Aluminium compounds in the +1 oxidation state are known, but are thermodynamically unstable with respect to disproportionation. Compounds of this type are typically oligomeric 6-8 , although monomeric systems that possess a metal-centred lone pair, such as Al(Nacnac) Dipp (where (Nacnac) Dipp  = (NDippCR) 2 CH and R =  t Bu, Me; Dipp = 2,6- i Pr 2 C 6 H 3 ), have also been reported 9,10 . Coordination of these species, and also of (η 5 -C 5 Me 5 )Al, to a range of Lewis acids has been observed 11-13 , but their primary mode of reactivity involves facile oxidative addition to generate Al(III) species 6-8,14-16 . Here we report the synthesis, structure and reaction chemistry of an anionic aluminium(I) nucleophile, the dimethylxanthene-stabilized potassium aluminyl [K{Al(NON)}] 2 (NON = 4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene). This species displays unprecedented reactivity in the formation of aluminium-element covalent bonds and in the C-H oxidative addition of benzene, suggesting that it could find further use in both metal-carbon and metal-metal bond-forming reactions.

Futurepath: The Story of Research and Technology at NASA Lewis Research Center. Structures for Flight Propulsion, ARC Sprayed Monotape, National Aero-Space Plane

NASA Technical Reports Server (NTRS)

1989-01-01

The story of research and technology at NASA Lewis Research Center's Structures Division is presented. The job and designs of the Structures Division needed for flight propulsion is described including structural mechanics, structural dynamics, fatigue, and fracture. The video briefly explains why properties of metals used in structural mechanics need to be tested. Examples of tests and simulations used in structural dynamics (bodies in motion) are briefly described. Destructive and non-destructive fatigue/fracture analysis is also described. The arc sprayed monotape (a composite material) is explained, as are the programs in which monotape plays a roll. Finally, the National Aero-Space Plane (NASP or x-30) is introduced, including the material development and metal matrix as well as how NASP will reduce costs for NASA.

Monocyte chemotactic protein-1 attenuates and high-fat diet exacerbates bone loss in mice with pulmonary metastasis of Lewis lung carcinoma

USDA-ARS?s Scientific Manuscript database

Bone can be adversely affected by obesity and cancer-associated complications including wasting. The objective of this study was to determine whether a high-fat diet and a deficiency in monocyte chemotactic protein-1 (MCP-1) altered bone structural defects found in male C57BL/6 mice with Lewis lung...

High-fat diet enhances and plasminogen activator inhibitor-1 deficiency attenuates bone loss in mice with Lewis Lung carcinoma

USDA-ARS?s Scientific Manuscript database

This study determined the effects of a high-fat diet and plasminogen activator inhibitor-1 deficiency (PAI-1-/-) on bone structure in mice bearing Lewis lung carcinoma (LLC) in lungs. Reduction in bone volume fraction (BV/TV) by 22% and 21%, trabecular number (Tb.N) by 8% and 4% and bone mineral de...

Comprehensive report of aeropropulsion, space propulsion, space power, and space science applications of the Lewis Research Center

NASA Technical Reports Server (NTRS)

1988-01-01

The research activities of the Lewis Research Center for 1988 are summarized. The projects included are within basic and applied technical disciplines essential to aeropropulsion, space propulsion, space power, and space science/applications. These disciplines are materials science and technology, structural mechanics, life prediction, internal computational fluid mechanics, heat transfer, instruments and controls, and space electronics.

Aeropropulsion facilities configuration control: Procedures manual

NASA Technical Reports Server (NTRS)

Lavelle, James J.

1990-01-01

Lewis Research Center senior management directed that the aeropropulsion facilities be put under configuration control. A Configuration Management (CM) program was established by the Facilities Management Branch of the Aeropropulsion Facilities and Experiments Division. Under the CM program, a support service contractor was engaged to staff and implement the program. The Aeronautics Directorate has over 30 facilities at Lewis of various sizes and complexities. Under the program, a Facility Baseline List (FBL) was established for each facility, listing which systems and their documents were to be placed under configuration control. A Change Control System (CCS) was established requiring that any proposed changes to FBL systems or their documents were to be processed as per the CCS. Limited access control of the FBL master drawings was implemented and an audit system established to ensure all facility changes are properly processed. This procedures manual sets forth the policy and responsibilities to ensure all key documents constituting a facilities configuration are kept current, modified as needed, and verified to reflect any proposed change. This is the essence of the CM program.

Neural correlates of cognitive dysfunction in Lewy body diseases and tauopathies: combined assessment with FDG-PET and the CERAD test battery.

PubMed

Hellwig, Sabine; Frings, Lars; Bormann, Tobias; Kreft, Annabelle; Amtage, Florian; Spehl, Timo S; Weiller, Cornelius; Tüscher, Oliver; Meyer, Philipp T

2013-11-01

We investigated disease-specific cognitive profiles and their neural correlates in Lewy-body diseases (LBD) and tauopathies by CERAD assessment and FDG-PET. Analyses revealed a significant interaction between reduced semantic fluency in tauopathies and impaired verbal learning in LBD. Semantic fluency discriminated between groups with high accuracy (83%). Compared to LBD, tauopathy patients showed bilateral hypometabolism of midbrain, thalamus, middle cingulate gyrus and supplementary motor/premotor cortex. In the reverse contrast, LBD patients exhibited bilateral hypometabolism in posterior parietal cortex, precuneus and inferior temporal gyrus extending into occipital and frontal cortices. In diagnosis-independent voxel-based analyses, verbal learning/memory correlated with left temporal and right parietal metabolism, while fluency was coupled to bilateral striatal and frontal metabolism. Naming correlated with left frontal metabolism and drawing with metabolism in bilateral temporal and left frontal regions. In line with disease-specific patterns of regional glucose metabolism, tauopathies and LBD show distinct cognitive profiles, which may assist clinical differentiation. Copyright © 2013 Elsevier Inc. All rights reserved.

Structural and Functional Neuroimaging of Visual Hallucinations in Lewy Body Disease: A Systematic Literature Review

PubMed Central

Cagnin, Annachiara; Bandmann, Oliver; Venneri, Annalena

2017-01-01

Patients with Lewy body disease (LBD) frequently experience visual hallucinations (VH), well-formed images perceived without the presence of real stimuli. The structural and functional brain mechanisms underlying VH in LBD are still unclear. The present review summarises the current literature on the neural correlates of VH in LBD, namely Parkinson’s disease (PD), and dementia with Lewy bodies (DLB). Following a systematic literature search, 56 neuroimaging studies of VH in PD and DLB were critically reviewed and evaluated for quality assessment. The main structural neuroimaging results on VH in LBD revealed grey matter loss in frontal areas in patients with dementia, and parietal and occipito-temporal regions in PD without dementia. Parietal and temporal hypometabolism was also reported in hallucinating PD patients. Disrupted functional connectivity was detected especially in the default mode network and fronto-parietal regions. However, evidence on structural and functional connectivity is still limited and requires further investigation. The current literature is in line with integrative models of VH suggesting a role of attention and perception deficits in the development of VH. However, despite the close relationship between VH and cognitive impairment, its associations with brain structure and function have been explored only by a limited number of studies. PMID:28714891

Novel interactions of complex carbohydrates with peanut (PNA), Ricinus communis (RCA-I), Sambucus nigra (SNA-I) and wheat germ (WGA) agglutinins as revealed by the binding specificities of these lectins towards mucin core-2 O-linked and N-linked glycans and related structures.

PubMed

Chandrasekaran, E V; Xue, Jun; Xia, Jie; Khaja, Siraj D; Piskorz, Conrad F; Locke, Robert D; Neelamegham, Sriram; Matta, Khushi L

2016-10-01

Plant lectins through their multivalent quaternary structures bind intrinsically flexible oligosaccharides. They recognize fine structural differences in carbohydrates and interact with different sequences in mucin core 2 or complex-type N-glycan chain and also in healthy and malignant tissues. They are used in characterizing cellular and extracellular glycoconjugates modified in pathological processes. We study here, the complex carbohydrate-lectin interactions by determining the effects of substituents in mucin core 2 tetrasaccharide Galβ1-4GlcNAcβ1-6(Galβ1-3)GalNAcα-O-R and fetuin glycopeptides on their binding to agarose-immobilized lectins PNA, RCA-I, SNA-I and WGA. Briefly, in mucin core 2 tetrasaccharide (i) structures modified by α2-3/6-Sialyl LacNAc, LewisX and α1-3-Galactosyl LacNAc resulted in regular binding to PNA whereas compounds with 6-sulfo LacNAc displayed no-binding; (ii) strucures bearing α2-6-sialyl 6-sulfo LacNAc, or 6-sialyl LacdiNAc carbohydrates displayed strong binding to SNA-I; (iii) structures with α2-3/6-sialyl, α1-3Gal LacNAc or LewisX were non-binder to RCA-I and compounds with 6-sulfo LacNAc only displayed weak binding; (iv) structures containing LewisX, 6-Sulfo LewisX, α2-3/6-sialyl LacNAc, α2-3/6-sialyl 6-sulfo LacNAc and GalNAc Lewis-a were non-binding to WGA, those with α1-2Fucosyl, α1-3-Galactosyl LacNAc, α2-3-sialyl T-hapten plus 3'/6'sulfo LacNAc displayed weak binding, and compounds with α2-3-sialyl T-hapten, α2.6-Sialyl LacdiNAc, α2-3-sialyl D-Fucβ1-3 GalNAc and Fucα-1-2 D-Fucβ-1-3GalNAc displaying regular binding and GalNAc LewisX and LacdiNAc plus D-Fuc β-1-3 GalNAcα resulting in tight binding. RCA-I binds Fetuin triantennary asialoglycopeptide 100 % after α-2-3 and 25 % after α-2-6 sialylation, 30 % after α-1-2 and 100 % after α-1-3 fucosylation, and 50 % after α-1-3 galactosylation. WGA binds 3-but not 6-Fucosyl chitobiose core. Thus, information on the influence of complex carbohydrate chain constituents on lectin binding is apparently essential for the potential application of lectins in glycoconjugate research.

Synchrotron FTIR micro-spectroscopy for structural analysis of Lewy bodies in the brain of Parkinson’s disease patients

NASA Astrophysics Data System (ADS)

Araki, Katsuya; Yagi, Naoto; Ikemoto, Yuka; Yagi, Hisashi; Choong, Chi-Jing; Hayakawa, Hideki; Beck, Goichi; Sumi, Hisae; Fujimura, Harutoshi; Moriwaki, Taro; Nagai, Yoshitaka; Goto, Yuji; Mochizuki, Hideki

2015-12-01

Lewy bodies (LBs), which mainly consist of α-synuclein (α-syn), are neuropathological hallmarks of patients with Parkinson’s disease (PD). The fine structure of LBs is unknown, and LBs cannot be made artificially. Nevertheless, many studies have described fibrillisation using recombinant α-syn purified from E. coli. An extremely fundamental problem is whether the structure of LBs is the same as that of recombinant amyloid fibrils. Thus, we used synchrotron Fourier transform infrared micro-spectroscopy (FTIRM) to analyse the fine structure of LBs in the brain of PD patients. Our results showed a shift in the infrared spectrum that indicates abundance of a β-sheet-rich structure in LBs. Also, 2D infrared mapping of LBs revealed that the content of the β-sheet structure is higher in the halo than in the core, and the core contains a large amount of proteins and lipids.

Biological activities of human mannose-binding lectin bound to two different ligand sugar structures, Lewis A and Lewis B antigens and high-mannose type oligosaccharides.

PubMed

Muto, S; Takada, T; Matsumoto, K

2001-07-02

The biological activities of mannose-binding lectin (MBL) which binds to different ligands on mammalian cells were examined using two types of Colo205 cells, a human colon adenocarcinoma cell line: one naturally expressing Lewis A and Lewis B antigens as ligands for MBL (NT-Colo205), and the other modified to express high-mannose type oligosaccharides by treatment with benzyl-2-acetamide-2-deoxy-alpha-galactopyranoside and 1-deoxymannojirimycin (Bz+dMM-Colo205). Although the final lysis was not observed, the deposition of C4 and C3 was observed on both types of Colo205 cells after treatment with MBL and complements as a result of complement activation by MBL. MBL bound to Bz+dMM-Colo205 could also activate human peripheral blood leukocytes and induce superoxide production; however, MBL bound to NT-Colo205 could not. This may be explained by the lower affinity of MBL to Lewis A and Lewis B antigens than to high-mannose type oligosaccharides under physiological conditions, since MBL bound to NT-Colo205 was more easily released from the cell surface than that bound to Bz+dMM-Colo205 at 37 degrees C. These findings suggest that the difference in the affinity of MBL to its ligands could influence the expression of some biological activities of MBL.

Phosphate modified ceria as a Brønsted acidic/redox multifunctional catalyst

DOE PAGES

Nelson, Nicholas C.; Wang, Zhuoran; Naik, Pranjali; ...

2017-01-06

Deposition of trimethylphosphate onto ceria followed by thermal treatment resulted in the formation of surface phosphates with retention of the ceria fluorite structure. The structural and chemical properties of the phosphate-functionalized ceria were studied using 31P solid-state NMR, XPS, zeta titration, ammonia thermal desorption, pyridine adsorption, and model reactions. The introduction of phosphates generated Brønsted acid sites and decreased the number of Lewis acid sites on the surface. The relative amount of Lewis and Brønsted acids can be controlled by the amount of trimethylphosphate used in the synthesis. Upon deposition of Pd, the multifunctional material showed enhanced activity for themore » hydrogenolysis of eugenol and guaiacol compared to Pd on the unmodified ceria support. As a result, this was attributed to the cooperativity between the Lewis acid sites, which activate the substrate for dearomatization, and the redox/Brønsted acid properties, which catalyze hydrogenolysis.« less

Providing Total Quality Fundamentals: 1995 Workshops for the NASA Lewis Research Center's Technical Services Directorate

NASA Technical Reports Server (NTRS)

Antczak, Paul; Jacinto,Gilda; Simek, Jimmy

1997-01-01

The National Aeronautics and Space Administration's (NASA) agency-wide movement to cultivate a quality workplace is the basis for Lewis Research Center to implement Total Quality Fundamentals (TQF) initiatives. The Lewis Technical Services Directorate (TSD) introduced the Total Quality Fundamentals (TQF) workshops to its work force as an opportunity to introduce the concepts and principles of TQF. These workshops also provided the participants with the opportunity to dialogue with fellow TSD employees and managers. This report describes, through the perspective of the Lewis TSD TQF Coaches, how the TQF work- shop process was accomplished in TSD. It describes the structure for addressing the need, implementation process, input the TSD Coaches provided, common themes and concerns raised, conclusions, and recommendations. The Coaches concluded that these types of workshops could be the key to open the communication channels that are necessary to help everyone at Lewis understand where they fit in the organization. TQF workshops can strengthen the participant's connection with the Mission, Vision of the Center, and Vision of the Agency. Reconunendations are given based on these conclusions that can help the TSD Quality Board develop attainable measures towards a quality workplace.

Methods for preparation of cyclopentadienyliron (II) arenes

DOEpatents

Keipert, Steven J.

1991-01-01

Two improved methods for preparation of compounds with the structure shown in equation X [(Cp)--Fe--(Ar)].sup.+.sub.b X.sup.b- (X) where Cp is an eta.sup.5 complexed, substituted or unsubstituted, cyclopentadienyl or indenyl anion, Ar is an eta.sup.6 complexed substituted or unsubstituted, pi-arene ligand anad X is a b-valent anion where b is an integer between 1 and 3. The two methods, which differ in the source of the cyclopentadienyl anion - Lewis acid complex, utilize a Lewis acid assisted ligand transfer reaction. The cyclopentadienyl anion ligand, assisted by a Lewis acid is transferred to ferrous ion in the presence of an arene. In the first method, the cyclopentadienyl anion is derived from ferrocene and ferrous chloride. In this reaction, the cyclopentadienyliron (II) arene product is derived partially from ferrocene and partially from the ferrous salt. In the second method, the cyclopentadienyl anion - Lewis acid complex is formed by direct reaction of the Lewis acid with an inorganic cyclopentadienide salt. The cyclopentadienyliron (II) arene product of this reaction is derived entirely from the ferrous salt. Cyclopentadienyliron (II) arene cations are of great interest due to their utility as photoactivatable catalysts for a variety of polymerization reactions.

Pre-mixed flame simulations for non-unity Lewis numbers

NASA Technical Reports Server (NTRS)

Rutland, C. J.; Trouve, A.

1990-01-01

A principal effect of turbulence on premixed flames in the flamelet region is to wrinkle the flame fronts. For non-unity Lewis numbers (Le), the local flame structure is altered in curved regions. This effect is examined using direct numerical simulations of the three dimensional, constant density, decaying isotropic turbulence with a single step, finite rate chemical reaction. Simulations of Lewis numbers 0.8, 1.0, and 1.2 are compared. The turbulent flame speed, S(sub T), increases as Le decreases. The correlation between S(sub T) and u prime found in previous Le = 1 simulations has a strong Lewis number dependency. The variance of the pdf of the flame curvature increases as Le decreases, indicating that the flames become more wrinkled. A strong correlation between local flame speed and curvature was found. For Le greater than 1, the flame speed increases in regions concave towards the products and decreases in convex regions. The opposite correlation was found for Le less than 1. The mean temperature of the products was also found to vary with Lewis number. For Le = 0.8, it is less than the adiabatic flame temperature and for Le = 1.2 it is greater.

Ion Thruster Development at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Sovey, James S.; Hamley, John A.; Patterson, Michael J.; Rawlin, Vincent K.; Sarver-Verhey, Timothy R.

1992-01-01

Recent ion propulsion technology efforts at NASA's Lewis Research Center including development of kW-class xenon ion thrusters, high power xenon and krypton ion thrusters, and power processors are reviewed. Thruster physical characteristics, performance data, life projections, and power processor component technology are summarized. The ion propulsion technology program is structured to address a broad set of mission applications from satellite stationkeeping and repositioning to primary propulsion using solar or nuclear power systems.

An order in Lewy body disorders: Retrograde degeneration in hyperbranching axons as a fundamental structural template accounting for focal/multifocal Lewy body disease.

PubMed

Uchihara, Toshiki

2017-04-01

Initial clinical recognition of "paralysis agitans" by James Parkinson was expanded by Jean-Martin Charcot, who recognized additional clinical findings of his own, such as slowness (distinct from paralysis), rigidity (distinct from spasticity) and characteristic countenance. Charcot assembled these findings under the umbrella of "Parkinson disease (PD)". This purely clinical concept was so prescient and penetrating that subsequent neuropathological and biochemical evidences were ordered along this axis to establish the nigra-central trinity of PD (dopamine depletion, nigral lesion with Lewy bodies: LBs). Although dramatic efficacy of levodopa boosted an enthusiasm for this nigra-centralism, extranigral lesions were identified, especially after identification of alpha-synuclein (αS) as a major constituent of LBs. Frequent αS lesions in the lower brainstem with their presumed upward spread were coupled with the self-propagating property of αS molecule, as a molecular template, to constitute the prion-Braak hypothesis. This hybrid concept might expectedly explain clinical, structural and biochemical features of PD/dementia with Lewy bodies (DLB) as if they were stereotypic. In spite of this ordered explanation, recent studies have demonstrated unexpectedly that αS lesions in the human brain, as well as their corresponding clinical manifestations, are much more disordered. Even with such a chaos of LB disorders, affected neuronal groups are uniformly characterized by hyperbranching axons, which may facilitate distal-dominant degeneration and retrograde progression of LB-related degeneration along axons as a fundamental structural order to template LB disorders. This "structural template" hypothesis may explain why: (i) some selective groups are prone to develop Lewy pathology; (ii) their clinical manifestations (especially non-motor components) are vague and generalized without somatotopic accentuation; (iii) distal axons and terminals are preferentially affected early, which is clinically detectable as reduced myocardial uptake of meta-iodobenzylguanidine in PD/DLB. Because each Lewy-prone system develops LBs independently, their isolated presentation as "focal LB disease" or their whatever combinations as "multifocal LB disease" are a more plausible framework to explain clinicopathological diversities of LB disorders. Clinical criteria are now being revised to integrate these clinicopathological disorders of PD/DLB. To gain closer access to the reality of the human brain, it is necessary to facilitate more interactions between clinicopathological and experimental fields so that both are mutually critical and complementary for improved diagnosis and treatment. © 2016 Japanese Society of Neuropathology.

Pentacoordinate silicon(IV): cationic, anionic and neutral complexes derived from the reaction of NHC→SiCl4 with highly Lewis acidic (C2F5)2SiH2.

PubMed

Böttcher, T; Steinhauer, S; Neumann, B; Stammler, H-G; Röschenthaler, G-V; Hoge, B

2014-06-14

Addition of NHC→SiCl4 to the highly Lewis acidic bis(pentafluoroethyl)silane ((C2F5)2SiH2) afforded the salt [(NHC)2SiCl2H][(C2F5)2SiCl3] with pentacoordinate silicon in the cation and the anion. The anion represents the first example of a chlorosilicate structurally characterized in the solid state. In this reaction, the long sought pentacoordinate NHC-adduct of silicochloroform was identified as an intermediate and its crystal structure is presented.

Test results of a 40-kW Stirling engine and comparison with the NASA Lewis computer code predictions

NASA Technical Reports Server (NTRS)

Allen, David J.; Cairelli, James E.

1988-01-01

A Stirling engine was tested without auxiliaries at Nasa-Lewis. Three different regenerator configurations were tested with hydrogen. The test objectives were: (1) to obtain steady-state and dynamic engine data, including indicated power, for validation of an existing computer model for this engine; and (2) to evaluate structurally the use of silicon carbide regenerators. This paper presents comparisons of the measured brake performance, indicated mean effective pressure, and cyclic pressure variations from those predicted by the code. The silicon carbide foam generators appear to be structurally suitable, but the foam matrix showed severely reduced performance.

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

Wu, Zili; Mann, Amanda K. P.; Li, Meijun

In addition to their well-known redox character, the acid-base property is another interesting aspect of ceria-based catalysts. Thus, the effect of surface structure on the acid-base property of ceria was studied in detail by utilizing ceria nanocrystals with different morphologies (cubes, octahedra and rods) that exhibit crystallographically well-defined surface facets. The nature, type, strength and amount of acid and base sites on these ceria nanoshapes were investigated via in situ IR spectroscopy combined with various probe molecules. Pyridine adsorption shows the presence of Lewis acid sites (Ce cations) on the ceria nanoshapes. These Lewis acid sites are relatively weak andmore » similar in strength among the three nanoshapes according to the probing by both pyridine and acetonitrile. Both Br nsted (hydroxyl group) and Lewis (surface lattice oxygen) base sites are present on the ceria nanoshapes as probed by CO2 adsorption. CO2 and chloroform adsorption indicate that the strength and amount of the Lewis base sites are shape dependent: rods > cubes > octahedra. Moreover, the weak and strong surface dependence of the acid and base sites, respectively, are a result of interplay between the surface structure dependent coordination unsaturation status of the Ce cations and O anions and the amount of defect sites on the three ceria nanoshapes. Furthermore, it was found that the nature of the acid-base sites of ceria can be impacted by impurities, such as Na and P residues that result from their use as structure-directing reagent in the hydrothermal synthesis of the ceria nanocrystals. Finally, our observation calls for precaution in interpreting the catalytic behavior of nanoshaped ceria where trace impurities may be present.« less

The qualitative scoring MMSE pentagon test (QSPT): a new method for differentiating dementia with Lewy Body from Alzheimer's disease.

PubMed

Caffarra, Paolo; Gardini, Simona; Dieci, Francesca; Copelli, Sandra; Maset, Laura; Concari, Letizia; Farina, Elisabetta; Grossi, Enzo

2013-01-01

The differential diagnosis across different variants of degenerative diseases is sometimes controversial. This study aimed to validate a qualitative scoring method for the pentagons copy test (QSPT) of Mini-Mental State Examination (MMSE) based on the assessment of different parameters of the pentagons drawing, such as number of angles, distance/intersection, closure/opening, rotation, closing-in, and to verify its efficacy to differentiate dementia with Lewy Body (DLB) from Alzheimer's disease (AD). We established the reliability of the qualitative scoring method through the inter-raters and intra-subjects analysis. QSPT was then applied to forty-six AD and forty-six DLB patients, using two phases statistical approach, standard and artificial neural network respectively. DLB patients had significant lower total score in the copy of pentagons and number of angles, distance/intersection, closure/opening, rotation compared to AD. However the logistic regression did not allow to establish any suitable modeling, whereas using Auto-Contractive Map (Auto-CM) the DLB was more strongly associated with low scores in some qualitative parameters of pentagon copying, i.e. number of angles and opening/closure and, for the remaining subitems of the MMSE, in naming, repetition and written comprehension, and for demographic variables of gender (male) and education (6-13 years). Twist system modeling showed that the QSPT had a good sensitivity (70.29%) and specificity (78.67%) (ROC-AUC 0.74). The proposed qualitative method of assessment of pentagons copying used in combination with non-linear analysis, showed to be consistent and effective in the differential diagnosis between Lewy Body and Alzheimer's dementia.

Lewis acid catalysis and ligand exchange in the asymmetric binaphthol-catalyzed propargylation of ketones.

PubMed

Grayson, Matthew N; Goodman, Jonathan M

2013-09-06

1,1'-Bi-2-naphthol (BINOL)-derived catalysts catalyze the asymmetric propargylation of ketones. Density functional theory (DFT) calculations show that the reaction proceeds via a closed six-membered transition structure (TS) in which the chiral catalyst undergoes an exchange process with the original cyclic boronate ligand. This leads to a Lewis acid type activation mode, not a Brønsted acid process, which accurately predicts the stereochemical outcome observed experimentally.

Carbonyl Activation by Borane Lewis Acid Complexation: Transition States of H2 Splitting at the Activated Carbonyl Carbon Atom in a Lewis Basic Solvent and the Proton-Transfer Dynamics of the Boroalkoxide Intermediate.

PubMed

Heshmat, Mojgan; Privalov, Timofei

2017-07-06

By using transition-state (TS) calculations, we examined how Lewis acid (LA) complexation activates carbonyl compounds in the context of hydrogenation of carbonyl compounds by H 2 in Lewis basic (ethereal) solvents containing borane LAs of the type (C 6 F 5 ) 3 B. According to our calculations, LA complexation does not activate a ketone sufficiently enough for the direct addition of H 2 to the O=C unsaturated bond; but, calculations indicate a possibly facile heterolytic cleavage of H 2 at the activated and thus sufficiently Lewis acidic carbonyl carbon atom with the assistance of the Lewis basic solvent (i.e., 1,4-dioxane or THF). For the solvent-assisted H 2 splitting at the carbonyl carbon atom of (C 6 F 5 ) 3 B adducts with different ketones, a number of TSs are computed and the obtained results are related to insights from experiment. By using the Born-Oppenheimer molecular dynamics with the DFT for electronic structure calculations, the evolution of the (C 6 F 5 ) 3 B-alkoxide ionic intermediate and the proton transfer to the alkoxide oxygen atom were investigated. The results indicate a plausible hydrogenation mechanism with a LA, that is, (C 6 F 5 ) 3 B, as a catalyst, namely, 1) the step of H 2 cleavage that involves a Lewis basic solvent molecule plus the carbonyl carbon atom of thermodynamically stable and experimentally identifiable (C 6 F 5 ) 3 B-ketone adducts in which (C 6 F 5 ) 3 B is the "Lewis acid promoter", 2) the transfer of the solvent-bound proton to the oxygen atom of the (C 6 F 5 ) 3 B-alkoxide intermediate giving the (C 6 F 5 ) 3 B-alcohol adduct, and 3) the S N 2-style displacement of the alcohol by a ketone or a Lewis basic solvent molecule. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structural Integrity and Durability of Reusable Space Propulsion Systems

NASA Technical Reports Server (NTRS)

1987-01-01

A two-day conference on the structural integrity and durability of reusable space propulsion systems was held on May 12 and 13, 1987, at the NASA Lewis research Center. Aerothermodynamic loads; instrumentation; fatigue, fracture, and constitutive modeling; and structural dynamics were discussed.

Design principles for nickel-hydrogen cells and batteries

NASA Technical Reports Server (NTRS)

Thaller, L. H.; Manzo, M. A.; Gonzalez-Sanabria, O. D.

1985-01-01

Nickel-hydrogen cells and, more recently, bipolar batteries have been built by a variety of organizations. The design principles that have been used by the technology group at the NASA Lewis Research Center draw upon their extensive background in separator technology, alkaline fuel cell technology, and several alkaline cell technology areas. These design principles have been incorporated into both the more contemporary individual pressure vessel (IPV) designs that were pioneered by other groups, as well as the more recent bipolar battery designs using active cooling that are being developed at NASA Lewis Research Center and under contract. These principles are rather straightforward applications of capillary force formalisms, coupled with the slowly developing data base resulting from careful post test analyses. The objective of this overall effort is directed towards the low-Earth-orbit (LEO) application where the cycle life requirements are much more severe than the geosynchronous-orbit (GEO) application. A summary of the design principles employed is presented along with a discussion of the recommendations for component pore sizes and pore size distributions, as well as suggested materials of construction. These will be made based on our experience in these areas to show how these design principles have been translated into operating hardware.

Design principles for nickel-hydrogen cells and batteries

NASA Technical Reports Server (NTRS)

Thaller, L. H.; Manzo, M. A.; Gonzalez-Sanabria, O. D.

1985-01-01

Nickel-hydrogen cells and, more recently, bipolar batteries have been built by a variety of organizations. The design principles that have been used by the technology group at the NASA Lewis Research Center draw upon their extensive background in separator technology, alkaline fuel cell technology, and several alkaline cell technology areas. These design principles have been incorporated into both the more contemporary individual pressure vessel (IPV) designs that were pioneered by other groups, as well as the more recent bipolar battery designs using active cooling that are being developed at NASA Lewis Research Center and under contract. These principles are rather straightforward applications of capillary force formalisms, coupled with the slowly developing data base resulting from careful post test analyses. The objective of this overall effort is directed towards the low-earth-orbit (LEO) application where the cycle life requirements are much more severe than the geosynchronous-orbit (GEO) application. A summary of the design principles employed is presented along with a discussion of the recommendations for component pore sizes and pore size distributions, as well as suggested materials of construction. These will be made based on our experience in these areas to show how these design principles have been translated into operating hardware.

NACA Researcher Examines the Cyclotron

NASA Image and Video Library

1951-02-21

Researcher James Blue examines the new cyclotron at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. Researchers at NACA Lewis began postulating about the use of atomic power for propulsion immediately after World War II. The NACA concentrated its efforts on the study of high temperature materials and heat transfer since it did not have access to the top secret fission information. The military studied the plausibility of nuclear propulsion for aircraft in the late 1940s. The military program was cancelled after four years without any breakthroughs, but the Atomic Energy Commission took on the effort in 1951. The NACA Lewis laboratory was expanding its nuclear-related research during this period. In 1948, Lewis engineers were assigned to the Oak Ridge National Laboratory to obtain expertise in high temperature heat transfer and advanced materials technology. The following year a new 80-person Nuclear Reactor Division was created, and an in-house nuclear school was established to train these researchers. The cyclotron was built behind the Materials and Structures Laboratory to support thermodynamic and materials research for both nuclear aircraft and nuclear rockets. The original NACA Lewis cyclotron was used to accelerate two kinds of particles. To better match the space radiation environment, the cyclotron was later modified to accelerate particles of the newly-discovered Van Allen radiation belts.

Aromatic Bagels: An Edible Resonance Analogy

ERIC Educational Resources Information Center

Lin, Shirley

2007-01-01

Two Lewis structures, resonance contributors, are used to describe benzene (the Kekule structure) in order to explain resonance theory to chemistry students. The students could create two bagel halves representing the Kekule structures of benzene in which the numbered toothpicks corresponds to the carbon atoms in the two structures and the x…

NO3- anions can act as Lewis acid in the solid state

NASA Astrophysics Data System (ADS)

Bauzá, Antonio; Frontera, Antonio; Mooibroek, Tiddo J.

2017-02-01

Identifying electron donating and accepting moieties is crucial to understanding molecular aggregation, which is of pivotal significance to biology. Anions such as NO3- are typical electron donors. However, computations predict that the charge distribution of NO3- is anisotropic and minimal on nitrogen. Here we show that when the nitrate's charge is sufficiently dampened by resonating over a larger area, a Lewis acidic site emerges on nitrogen that can interact favourably with electron rich partners. Surveys of the Cambridge Structural Database and Protein Data Bank reveal geometric preferences of some oxygen and sulfur containing entities around a nitrate anion that are consistent with this `π-hole bonding' geometry. Computations reveal donor-acceptor orbital interactions that confirm the counterintuitive Lewis π-acidity of nitrate.

Structural dynamics branch research and accomplishments

NASA Technical Reports Server (NTRS)

1990-01-01

Summaries are presented of fiscal year 1989 research highlights from the Structural Dynamics Branch at NASA Lewis Research Center. Highlights from the branch's major work areas include aeroelasticity, vibration control, dynamic systems, and computation structural methods. A listing of the fiscal year 1989 branch publications is given.

Molecular cloning and functional expression of Lewis type α1,3/α1,4-fucosyltransferase cDNAs from Mangifera indica L.

PubMed

Okada, Takahiro; Ihara, Hideyuki; Ito, Ritsu; Ikeda, Yoshitaka

2017-12-01

In higher plants, complex type N-glycans contain characteristic carbohydrate moieties that are not found in mammals. In particular, the attachment of the Lewis a (Le a ) epitope is currently the only known outer chain elongation that is present in plant N-glycans. Such a modification is of great interest in terms of the biological function of complex type N-glycans in plant species. However, little is known regarding the exact molecular basis underlying their Le a expression. In the present study, we cloned two novel Lewis type fucosyltransferases (MiFUT13) from mango fruit, Mangifera indica L., heterologously expressed the proteins and structurally and functionally characterized them. Using an HPLC-based assay, we demonstrated that the recombinant MiFUT13 proteins mediate the α1,4-fucosylation of acceptor tetrasaccharides with a strict preference for type I-based structure to type II. The results and other findings suggest that MiFUT13s are involved in the biosynthesis of Le a containing glycoconjugates in mango fruits. Copyright © 2017 Elsevier Ltd. All rights reserved.

Near-limit flame structures at low Lewis number

NASA Technical Reports Server (NTRS)

Ronney, Paul D.

1990-01-01

The characteristics of premixed gas flames in mixtures with low Lewis numbers near flammability limits were studied experimentally using a low-gravity environment to reduce buoyant convection. The behavior of such flames was found to be dominated by diffusive-thermal instabilities. For sufficiently reactive mixtures, cellular structures resulting from these instabilities were observed and found to spawn new cells in regular patterns. For less reactive mixtures, cells formed shortly after ignition but did not spawn new cells; instead these cells evolved into a flame structure composed of stationary, apparently stable spherical flamelets. Experimental observations are found to be in qualitative agreement with elementary analytical models based on the interaction of heat release due to chemical reaction, differential diffusion of thermal energy and mass, flame front curvature, and volumetric heat losses due to gas and/or soot radiation.

Composite mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1987-01-01

Recent research activities and accomplishments at Lewis Research Center on composite mechanics for engine structures are summarized. The activities focused mainly on developing procedures for the computational simulation of composite intrinsic and structural behavior. The computational simulation encompasses all aspects of composite mechanics, advanced three-dimensional finite-element methods, damage tolerance, composite structural and dynamic response, and structural tailoring and optimization.

Composite mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1989-01-01

Recent research activities and accomplishments at Lewis Research Center on composite mechanics for engine structures are summarized. The activities focused mainly on developing procedures for the computational simulation of composite intrinsic and structural behavior. The computational simulation encompasses all aspects of composite mechanics, advanced three-dimensional finite-element methods, damage tolerance, composite structural and dynamic response, and structural tailoring and optimization.

Structural Dynamics Branch research and accomplishments for FY 1990

NASA Technical Reports Server (NTRS)

1991-01-01

Presented here is a collection of FY 1990 research highlights from the Structural Dynamics Branch at the NASA Lewis Research Center. Highlights are from the branch's major work areas: aeroelasticity, vibration control, dynamic systems, and computational structural methods. A listing is given of FY 1990 branch publications.

Xenon Treatment Protects Against Cold Ischemia Associated Delayed Graft Function and Prolongs Graft Survival in Rats

PubMed Central

Zhao, H; Watts, H R; Chong, M; Huang, H; Tralau-Stewart, C; Maxwell, P H; Maze, M; George, A J T; Ma, D

2013-01-01

Prolonged hypothermic storage causes ischemia-reperfusion injury (IRI) in the renal graft, which is considered to contribute to the occurrence of the delayed graft function (DGF) and chronic graft failure. Strategies are required to protect the graft and to prolong renal graft survival. We demonstrated that xenon exposure to human proximal tubular cells (HK-2) led to activation of range of protective proteins. Xenon treatment prior to or after hypothermia–hypoxia challenge stabilized the HK-2 cellular structure, diminished cytoplasmic translocation of high-mobility group box (HMGB) 1 and suppressed NF-κB activation. In the syngeneic Lewis-to-Lewis rat model of kidney transplantation, xenon exposure to donors before graft retrieval or to recipients after engraftment decreased caspase-3 expression, localized HMGB-1 within nuclei and prevented TLR-4/NF-κB activation in tubular cells; serum pro-inflammatory cytokines IL-1β, IL-6 and TNF-α were reduced and renal function was preserved. Xenon treatment of graft donors or of recipients prolonged renal graft survival following IRI in both Lewis-to-Lewis isografts and Fischer-to-Lewis allografts. Xenon induced cell survival or graft functional recovery was abolished by HIF-1α siRNA. Our data suggest that xenon treatment attenuates DGF and enhances graft survival. This approach could be translated into clinical practice leading to a considerable improvement in long-term graft survival. PMID:23710625

A Review of Recent Aeroelastic Analysis Methods for Propulsion at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Reddy, T. S. R.; Bakhle, Milind A.; Srivastava, R.; Mehmed, Oral; Stefko, George L.

1993-01-01

This report reviews aeroelastic analyses for propulsion components (propfans, compressors and turbines) being developed and used at NASA LeRC. These aeroelastic analyses include both structural and aerodynamic models. The structural models include a typical section, a beam (with and without disk flexibility), and a finite-element blade model (with plate bending elements). The aerodynamic models are based on the solution of equations ranging from the two-dimensional linear potential equation to the three-dimensional Euler equations for multibladed configurations. Typical calculated results are presented for each aeroelastic model. Suggestions for further research are made. Many of the currently available aeroelastic models and analysis methods are being incorporated in a unified computer program, APPLE (Aeroelasticity Program for Propulsion at LEwis).

154. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) ...

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

154. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) STRUCTURAL PLANS FOR MST STATION 30, SHEET S84 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Hypersonic engine seal development at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.

1994-01-01

NASA Lewis Research Center is developing advanced seal concepts and sealing technology for advanced combined cycle ramjet/scramjet engines being designed for the National Aerospace Plane (NASP). Technologies are being developed for both the dynamic seals that seal the sliding interfaces between articulating engine panels and sidewalls, and for the static seals that seal the heat exchanger to back-up structure interfaces. This viewgraph presentation provides an overview of the candidate engine seal concepts, seal material assessments, and unique test facilities used to assess the leakage and thermal performance of the seal concepts.

Flame balls dynamics in divergent channel

NASA Astrophysics Data System (ADS)

Fursenko, R.; Minaev, S.

2011-12-01

A three-dimensional reaction-diffusion model for lean low-Lewis-number premixed flames with radiative heat losses propagating in divergent channel is studied numerically. Effects of inlet gas velocity and heat-loss intensity on flame structure at low Lewis numbers are investigated. It is found that continuous flame front exists at small heat losses and the separate flame balls settled within restricted domain inside the divergent channel at large heat losses. It is shown that the time averaged flame balls coordinate may be considered as important characteristic analogous to coordinate of continuous flame stabilized in divergent channel.

Hypersonic engine seal development at NASA Lewis Research Center

NASA Astrophysics Data System (ADS)

Steinetz, Bruce M.

1994-07-01

NASA Lewis Research Center is developing advanced seal concepts and sealing technology for advanced combined cycle ramjet/scramjet engines being designed for the National Aerospace Plane (NASP). Technologies are being developed for both the dynamic seals that seal the sliding interfaces between articulating engine panels and sidewalls, and for the static seals that seal the heat exchanger to back-up structure interfaces. This viewgraph presentation provides an overview of the candidate engine seal concepts, seal material assessments, and unique test facilities used to assess the leakage and thermal performance of the seal concepts.

Monocyte chemotactic protein-1 deficiency attenuates and high-fat diet exacerbates bone loss in mice with Lewis lung carcinoma.

PubMed

Yan, Lin; Nielsen, Forrest H; Sundaram, Sneha; Cao, Jay

2017-04-04

Bone loss occurs in obesity and cancer-associated complications including wasting. This study determined whether a high-fat diet and a deficiency in monocyte chemotactic protein-1 (MCP-1) altered bone structural defects in male C57BL/6 mice with Lewis lung carcinoma (LLC) metastases in lungs. Compared to non-tumor-bearing mice, LLC reduced bone volume fraction, connectivity density, trabecular number, trabecular thickness and bone mineral density and increased trabecular separation in femurs. Similar changes occurred in vertebrae. The high-fat diet compared to the AIN93G diet exacerbated LLC-induced detrimental structural changes; the exacerbation was greater in femurs than in vertebrae. Mice deficient in MCP-1 compared to wild-type mice exhibited increases in bone volume fraction, connectivity density, trabecular number and decreases in trabecular separation in both femurs and vertebrae, and increases in trabecular thickness and bone mineral density and a decrease in structure model index in vertebrae. Lewis lung carcinoma significantly decreased osteocalcin but increased tartrate-resistant acid phosphatase 5b (TRAP 5b) in plasma. In LLC-bearing mice, the high-fat diet increased and MCP-1 deficiency decreased plasma TRAP 5b; neither the high-fat diet nor MCP-1 deficiency resulted in significant changes in plasma concentration of osteocalcin. In conclusion, pulmonary metastasis of LLC is accompanied by detrimental bone structural changes; MCP-1 deficiency attenuates and high-fat diet exacerbates the metastasis-associated bone wasting.

STS-107 Mission Highlights Resource, Part 2 of 4

NASA Technical Reports Server (NTRS)

2003-01-01

This video, Part 2 of 4, shows the activities of the STS-107 crew during flight days 4 through 7 of the Columbia orbiter's final flight. The crew consists of Commander Rick Husband, Pilot William McCool, Payload Commander Michael Anderson, Mission Specialists David Brown, Kalpana Chawla, and Laurel Clark, and Payload Specialist Ilan Ramon. During the video the crew members are at work on a variety of spaceborne experiments, such as the Laminar Soot Processes (LSP) experiment, the Mediterranean Israeli Dust Experiment (MEIDEX), international student experiments, and the Structures of Flame Balls at Low Lewis-number (SOFBALL) experiment. Other crew activities recorded on the video include exercising on a bicycle, drawing blood, and answering questions from the public. A couple of scenes on the video are narrated by Clark, including one in which she gives a tour of the SPACEHAB module in the shuttle's payload bay. The video also includes a scene in which Israeli Prime Minister Ariel Sharon addresses Ramon and the other Red Team crew members (Husband, Chawla, Clark). The Earth views shown include Saudi Arabia and the Persian Gulf; the Appalachian Mountains; Egypt, the Red Sea, and the Sinai Peninsula, and the east coast of Africa.

Duplex development and abandonment during evolution of the Lewis thrust system, southern Glacier National Park, Montana

NASA Astrophysics Data System (ADS)

Yin, An; Kelty, Thomas K.; Davis, Gregory A.

1989-09-01

Geologic mapping in southern Glacier National Park, Montana, reveals the presence of two duplexes sharing the same floor thrust fault, the Lewis thrust. The westernmost duplex (Brave Dog Mountain) includes the low-angle Brave Dog roof fault and Elk Mountain imbricate system, and the easternmost (Rising Wolf Mountain) duplex includes the low-angle Rockwell roof fault and Mt. Henry imbricate system. The geometry of these duplexes suggests that they differ from previously described geometric-kinematic models for duplex development. Their low-angle roof faults were preexisting structures that were locally utilized as roof faults during the formation of the imbricate systems. Crosscutting of the Brave Dog fault by the Mt. Henry imbricate system indicates that the two duplexes formed at different times. The younger Rockwell-Mt. Henry duplex developed 20 km east of the older Brave Dog-Elk Mountain duplex; the roof fault of the former is at a higher structural level. Field relations confirm that the low-angle Rockwell fault existed across the southern Glacier Park area prior to localized formation of the Mt. Henry imbricate thrusts beneath it. These thrusts kinematically link the Rockwell and Lewis faults and may be analogous to P shears that form between two synchronously active faults bounding a simple shear system. The abandonment of one duplex and its replacement by another with a new and higher roof fault may have been caused by (1) warping of the older and lower Brave Dog roof fault during the formation of the imbricate system (Elk Mountain) beneath it, (2) an upward shifting of the highest level of a simple shear system in the Lewis plate to a new decollement level in subhorizontal belt strata (= the Rockwell fault) that lay above inclined strata within the first duplex, and (3) a reinitiation of P-shear development (= Mt. Henry imbricate faults) between the Lewis thrust and the subparallel, synkinematic Rockwell fault.

2. Photocopy of drawing (1976 structural and electrical drawing by ...

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

2. Photocopy of drawing (1976 structural and electrical drawing by the Strategic Air Command, USAF) SITE PLAN, STRUCTURAL AND ELECTRICAL FOR RELOCATING WAREHOUSE, SHEET 1 OF 1 - Vandenberg Air Force Base, Space Launch Complex 3, Storage Shed, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

152. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) ...

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

152. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) STRUCTURAL DETAILS FOR MST STATIONS 21, 30, 39, AND 48, SHEET S98 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Interfacing modules for integrating discipline specific structural mechanics codes

NASA Technical Reports Server (NTRS)

Endres, Ned M.

1989-01-01

An outline of the organization and capabilities of the Engine Structures Computational Simulator (Simulator) at NASA Lewis Research Center is given. One of the goals of the research at Lewis is to integrate various discipline specific structural mechanics codes into a software system which can be brought to bear effectively on a wide range of engineering problems. This system must possess the qualities of being effective and efficient while still remaining user friendly. The simulator was initially designed for the finite element simulation of gas jet engine components. Currently, the simulator has been restricted to only the analysis of high pressure turbine blades and the accompanying rotor assembly, although the current installation can be expanded for other applications. The simulator presently assists the user throughout its procedures by performing information management tasks, executing external support tasks, organizing analysis modules and executing these modules in the user defined order while maintaining processing continuity.

Adsorption of molecular additive onto lead halide perovskite surfaces: A computational study on Lewis base thiophene additive passivation

NASA Astrophysics Data System (ADS)

Zhang, Lei; Yu, Fengxi; Chen, Lihong; Li, Jingfa

2018-06-01

Organic additives, such as the Lewis base thiophene, have been successfully applied to passivate halide perovskite surfaces, improving the stability and properties of perovskite devices based on CH3NH3PbI3. Yet, the detailed nanostructure of the perovskite surface passivated by additives and the mechanisms of such passivation are not well understood. This study presents a nanoscopic view on the interfacial structure of an additive/perovskite interface, consisting of a Lewis base thiophene molecular additive and a lead halide perovskite surface substrate, providing insights on the mechanisms that molecular additives can passivate the halide perovskite surfaces and enhance the perovskite-based device performance. Molecular dynamics study on the interactions between water molecules and the perovskite surfaces passivated by the investigated additive reveal the effectiveness of employing the molecular additives to improve the stability of the halide perovskite materials. The additive/perovskite surface system is further probed via molecular engineering the perovskite surfaces. This study reveals the nanoscopic structure-property relationships of the halide perovskite surface passivated by molecular additives, which helps the fundamental understanding of the surface/interface engineering strategies for the development of halide perovskite based devices.

4. PHOTOCOPY OF DRAWING (1976 STRUCTURAL AND ELECTRICAL DRAWING BY ...

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

4. PHOTOCOPY OF DRAWING (1976 STRUCTURAL AND ELECTRICAL DRAWING BY THE SPACE AND MISSILE TEST CENTER, VAFB, USAF) STRUCTURAL AND ELECTRICAL DIAGRAM FOR EQUIPMENT STORAGE BUILDING, SHEET S-26 - Vandenberg Air Force Base, Space Launch Complex 3, Storage Shed, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

199. Photocopy of drawing (1976 structural drawing by the Space ...

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

199. Photocopy of drawing (1976 structural drawing by the Space and Missile Test Center, VAFB, USAF) STRUCTURAL DETAILS FOR THE MST STAND-TALKERS SHELTER, SHEET S24 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

An efficient algorithm for planar drawing of RNA structures with pseudoknots of any type.

PubMed

Byun, Yanga; Han, Kyungsook

2016-06-01

An RNA pseudoknot is a tertiary structural element in which bases of a loop pair with complementary bases are outside the loop. A drawing of RNA secondary structures is a tree, but a drawing of RNA pseudoknots is a graph that has an inner cycle within a pseudoknot and possibly outer cycles formed between the pseudoknot and other structural elements. Visualizing a large-scale RNA structure with pseudoknots as a planar drawing is challenging because a planar drawing of an RNA structure requires both pseudoknots and an entire structure enclosing the pseudoknots to be embedded into a plane without overlapping or crossing. This paper presents an efficient heuristic algorithm for visualizing a pseudoknotted RNA structure as a planar drawing. The algorithm consists of several parts for finding crossing stems and page mapping the stems, for the layout of stem-loops and pseudoknots, and for overlap detection between structural elements and resolving it. Unlike previous algorithms, our algorithm generates a planar drawing for a large RNA structure with pseudoknots of any type and provides a bracket view of the structure. It generates a compact and aesthetic structure graph for a large pseudoknotted RNA structure in O([Formula: see text]) time, where n is the number of stems of the RNA structure.

A combined theoretical and Cambridge Structural Database study of π-hole pnicogen bonding complexes between electron rich molecules and both nitro compounds and inorganic bromides (YO2Br, Y = N, P, and As).

PubMed

Bauzá, Antonio; Ramis, Rafael; Frontera, Antonio

2014-04-17

Quantum calculations at the DFT-D3/def2-TZVPD level of theory have been used to examine complexes between O2YBr (Y═N, P, and As) molecules and several Lewis bases, that is, NH3, H2O, and HF. The interactions of the lone pair of the ammonia, water, and hydrogen fluoride with the σ-hole and π-hole of O2YBr molecules have been considered. In general, the complexes where the Lewis base lone pair interacts with the π-hole are more favorable than those with σ-hole. The nature of the interactions has been characterized with the Bader theory of atoms in molecules (AIM). We have also studied the ability of trifluoronitromethane and nitromethane to interact with anions using their π-hole along with an analysis the Cambridge Structural Database. We have found a large number of hits that provide strong experimental support for ability of the nitryl (-NO2) group to interact with anions and Lewis bases. In some X-ray structures, the π-hole interaction is crucial in the crystal packing and has a strong influence in the solid state architecture of the complexes. Finally, due to the relevance in atmospheric chemistry, we have studied noncovalent σ/π-hole complexes of nitryl bromide with ozone.

Structural basis for the interaction between human milk oligosaccharides and the bacterial lectin PA-IIL of Pseudomonas aeruginosa

PubMed Central

2005-01-01

One of the mechanisms contributing to the protection by breast-feeding of the newborn against enteric diseases is related to the ability of human milk oligosaccharides to prevent the attachment of pathogenic bacteria to the duodenual epithelium. Indeed, a variety of fucosylated oligosaccharides, specific to human milk, form part of the innate immune system. In the present study, we demonstrate the specific blocking of PA-IIL, a fucose-binding lectin of the human pathogen Pseudomonas aeruginosa, by milk oligosaccharides. Two fucosylated epitopes, Lewis a and 3-fucosyl-lactose (Lewis x glucose analogue) bind to the lectin with dissociation constants of 2.2×10−7 M and 3.6×10−7 M respectively. Thermodynamic studies indicate that these interactions are dominated by enthalpy. The entropy contribution is slightly favourable when binding to fucose and to the highest-affinity ligand, Lewis a. The high-resolution X-ray structures of two complexes of PA-IIL with milk oligosaccharides allow the precise determination of the conformation of a trisaccharide and a pentasaccharide. The different types of interaction between the oligosaccharides and the protein involve not only hydrogen bonding, but also calcium- and water-bridged contacts, allowing a rationalization of the thermodynamic data. This study provides important structural information about compounds that could be of general application in new therapeutic strategies against bacterial infections. PMID:15790314

Lewis Information Network (LINK): Background and overview

NASA Technical Reports Server (NTRS)

Schulte, Roger R.

1987-01-01

The NASA Lewis Research Center supports many research facilities with many isolated buildings, including wind tunnels, test cells, and research laboratories. These facilities are all located on a 350 acre campus adjacent to the Cleveland Hopkins Airport. The function of NASA-Lewis is to do basic and applied research in all areas of aeronautics, fluid mechanics, materials and structures, space propulsion, and energy systems. These functions require a great variety of remote high speed, high volume data communications for computing and interactive graphic capabilities. In addition, new requirements for local distribution of intercenter video teleconferencing and data communications via satellite have developed. To address these and future communications requirements for the next 15 yrs, a project team was organized to design and implement a new high speed communication system that would handle both data and video information in a common lab-wide Local Area Network. The project team selected cable television broadband coaxial cable technology as the communications medium and first installation of in-ground cable began in the summer of 1980. The Lewis Information Network (LINK) became operational in August 1982 and has become the backbone of all data communications and video.

Episodic Memory in Alzheimer Disease, Frontotemporal Dementia, and Dementia With Lewy Bodies/Parkinson Disease Dementia: Disentangling Retrieval From Consolidation.

PubMed

Economou, Alexandra; Routsis, Christopher; Papageorgiou, Sokratis G

2016-01-01

Differences in episodic memory performance in patients with Alzheimer disease (AD), frontotemporal dementia (FTD), dementia with Lewy bodies (DLB)/Parkinson disease with dementia (PDD) are inconsistent and task dependent. The inconsistencies may be attributed to the different tasks drawing on different memory processes. Few studies have examined episodic memory impairment in the above groups using memory tests that facilitate encoding, to distinguish memory deficits due to impairment of specific processes. We examined the memory performance of 106 AD patients, 51 FTD patients, 26 DLB/PDD patients, and 37 controls using the Five-Words Test, a 5-item memory test that facilitates encoding. The patient groups did not differ in modified Mini Mental State Examination scores. AD patients scored lowest on the Five-Words Test overall, and showed the greatest reduction from immediate total recall to delayed free recall relative to the other 2 groups, consistent with a predominantly consolidation deficit. DLB/PDD patients showed the largest improvement from delayed free to delayed total recall relative to the other 2 groups, consistent with a predominantly retrieval deficit. Deficits in both consolidation and retrieval underlie the memory impairment of the patients, to different extents, and contribute to the theoretical understanding of the nature of the memory impairment of the patient groups.

An exploratory study of proficient undergraduate Chemistry II students' application of Lewis's model

NASA Astrophysics Data System (ADS)

Lewis, Sumudu R.

This exploratory study was based on the assumption that proficiency in chemistry must not be determined exclusively on students' declarative and procedural knowledge, but it should be also described as the ability to use variety of reasoning strategies that enrich and diversify procedural methods. The study furthermore assumed that the ability to describe the structure of a molecule using Lewis's model and use it to predict its geometry as well as some of its properties is indicative of proficiency in the essential concepts of covalent bonding and molecule structure. The study therefore inquired into the reasoning methods and procedural techniques of proficient undergraduate Chemistry II students when solving problems, which require them to use Lewis's model. The research design included an original survey, designed by the researcher for this study, and two types of interviews, with students and course instructors. The purpose of the survey was two-fold. First and foremost, the survey provided a base for the student interview selection, and second it served as the foundation for the inquiry into the strategies the student use when solving survey problems. Twenty two students were interviewed over the course of the study. The interview with six instructors allowed to identify expected prior knowledge and skills, which the students should have acquired upon completion of the Chemistry I course. The data, including videos, audios, and photographs of the artifacts produced by students during the interviews, were organized and analyzed manually and using QSR NVivo 10. The research found and described the differences between proficient and non-proficient students' reasoning and procedural strategies when using Lewis's model to describe the structure of a molecule. One of the findings clearly showed that the proficient students used a variety of cues to reason, whereas other students used one memorized cue, or an algorithm, which often led to incorrect representations in cases where the algorithm cannot be applied. Additionally, the proficient students' understanding (i.e., representation, explanation and application) of the Valence Shell Electron-Pair Repulsion theory was accurate and precise, and they used the key terms in the correct context when explaining their reasoning. The results of this study can be of great importance to general chemistry and organic chemistry courses' instructors. This study identified students' baseline academic skills and abilities that lead to conceptual understanding of the essential concepts of covalent bonding and molecule structure, which instructors could use as a guide for developing instruction. Furthermore knowing the effective methods of reasoning the students use while applying Lewis's model, the instructors may be better informed and be able to better facilitate students' learning of Lewis' model and its application. Finally, the ideas and methods used in this study can be of value to chemistry education researchers to learn more about developing proficiency through reasoning methods in other chemistry concepts.

APPLE - An aeroelastic analysis system for turbomachines and propfans

NASA Technical Reports Server (NTRS)

Reddy, T. S. R.; Bakhle, Milind A.; Srivastava, R.; Mehmed, Oral

1992-01-01

This paper reviews aeroelastic analysis methods for propulsion elements (advanced propellers, compressors and turbines) being developed and used at NASA Lewis Research Center. These aeroelastic models include both structural and aerodynamic components. The structural models include the typical section model, the beam model with and without disk flexibility, and the finite element blade model with plate bending elements. The aerodynamic models are based on the solution of equations ranging from the two-dimensional linear potential equation for a cascade to the three-dimensional Euler equations for multi-blade configurations. Typical results are presented for each aeroelastic model. Suggestions for further research are indicated. All the available aeroelastic models and analysis methods are being incorporated into a unified computer program named APPLE (Aeroelasticity Program for Propulsion at LEwis).

An Overview-NASA LeRC Structures Program

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.

1997-01-01

The Structures and Acoustics Division of the NASA Lewis Research Center has its genesis dating back to 1943. It has been an independent Division at Lewis since 1979. Its two primary capabilities are performance and life analysis of static and dynamic systems such as those found in aircraft and spacecraft propulsion systems and experimental verification of these analyses. Research is conducted in-house, through university grants and contracts, and through cooperative programs with industry. Our work directly supports NASA's Advanced Subsonic Technology (AST), Smart Green Engine, Fast Quiet Engine, High-Temperature Materials and Processing (HiTEMP), Hybrid Hyperspeed Propulsion, Rotorcraft, High-Speed Research (HSR), and Aviation Safety Program (AvSP). A general overview is given discussing these programs and other technologies that are being developed at NASA LeRC.

Metabolic connectomics targeting brain pathology in dementia with Lewy bodies

PubMed Central

Caminiti, Silvia P; Tettamanti, Marco; Sala, Arianna; Presotto, Luca; Iannaccone, Sandro; Cappa, Stefano F; Magnani, Giuseppe

2016-01-01

Dementia with Lewy bodies is characterized by α-synuclein accumulation and degeneration of dopaminergic and cholinergic pathways. To gain an overview of brain systems affected by neurodegeneration, we characterized the [18F]FDG-PET metabolic connectivity in 42 dementia with Lewy bodies patients, as compared to 42 healthy controls, using sparse inverse covariance estimation method and graph theory. We performed whole-brain and anatomically driven analyses, targeting cholinergic and dopaminergic pathways, and the α-synuclein spreading. The first revealed substantial alterations in connectivity indexes, brain modularity, and hubs configuration. Namely, decreases in local metabolic connectivity within occipital cortex, thalamus, and cerebellum, and increases within frontal, temporal, parietal, and basal ganglia regions. There were also long-range disconnections among these brain regions, all supporting a disruption of the functional hierarchy characterizing the normal brain. The anatomically driven analysis revealed alterations within brain structures early affected by α-synuclein pathology, supporting Braak’s early pathological staging in dementia with Lewy bodies. The dopaminergic striato-cortical pathway was severely affected, as well as the cholinergic networks, with an extensive decrease in connectivity in Ch1-Ch2, Ch5-Ch6 networks, and the lateral Ch4 capsular network significantly towards the occipital cortex. These altered patterns of metabolic connectivity unveil a new in vivo scenario for dementia with Lewy bodies underlying pathology in terms of changes in whole-brain metabolic connectivity, spreading of α-synuclein, and neurotransmission impairment. PMID:27306756

Xenon treatment protects against cold ischemia associated delayed graft function and prolongs graft survival in rats.

PubMed

Zhao, H; Watts, H R; Chong, M; Huang, H; Tralau-Stewart, C; Maxwell, P H; Maze, M; George, A J T; Ma, D

2013-08-01

Prolonged hypothermic storage causes ischemia-reperfusion injury (IRI) in the renal graft, which is considered to contribute to the occurrence of the delayed graft function (DGF) and chronic graft failure. Strategies are required to protect the graft and to prolong renal graft survival. We demonstrated that xenon exposure to human proximal tubular cells (HK-2) led to activation of range of protective proteins. Xenon treatment prior to or after hypothermia-hypoxia challenge stabilized the HK-2 cellular structure, diminished cytoplasmic translocation of high-mobility group box (HMGB) 1 and suppressed NF-κB activation. In the syngeneic Lewis-to-Lewis rat model of kidney transplantation, xenon exposure to donors before graft retrieval or to recipients after engraftment decreased caspase-3 expression, localized HMGB-1 within nuclei and prevented TLR-4/NF-κB activation in tubular cells; serum pro-inflammatory cytokines IL-1β, IL-6 and TNF-α were reduced and renal function was preserved. Xenon treatment of graft donors or of recipients prolonged renal graft survival following IRI in both Lewis-to-Lewis isografts and Fischer-to-Lewis allografts. Xenon induced cell survival or graft functional recovery was abolished by HIF-1α siRNA. Our data suggest that xenon treatment attenuates DGF and enhances graft survival. This approach could be translated into clinical practice leading to a considerable improvement in long-term graft survival. © Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons.

225. Photocopy of drawing (1967 structural drawing by General Dynamics/Astronautics) ...

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

225. Photocopy of drawing (1967 structural drawing by General Dynamics/Astronautics) WIND DEFLECTOR FOR THE UMBILICAL MAST, SHEET S122 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

158. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) ...

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

158. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) FRAMING PLANS FOR MST STATION 124, SHEET S94 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Probabilistic structural analysis methods of hot engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Hopkins, D. A.

1989-01-01

Development of probabilistic structural analysis methods for hot engine structures is a major activity at Lewis Research Center. Recent activities have focused on extending the methods to include the combined uncertainties in several factors on structural response. This paper briefly describes recent progress on composite load spectra models, probabilistic finite element structural analysis, and probabilistic strength degradation modeling. Progress is described in terms of fundamental concepts, computer code development, and representative numerical results.

Lewis base activation of Lewis acids: development of a Lewis base catalyzed selenolactonization.

PubMed

Denmark, Scott E; Collins, William R

2007-09-13

The concept of Lewis base activation of Lewis acids has been applied to the selenolactonization reaction. Through the use of substoichiometric amounts of Lewis bases with "soft" donor atoms (S, Se, P) significant rate enhancements over the background reaction are seen. Preliminary mechanistic investigations have revealed the resting state of the catalyst as well as the significance of a weak Brønsted acid promoter.

153. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) ...

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

153. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) PLANS, ELEVATIONS, AND DETAILS FOR MST STATION 3, SHEET A20 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Quantification of Lewis acid induced Brønsted acidity of protogenic Lewis bases.

PubMed

Lathem, A Paige; Heiden, Zachariah M

2017-05-09

Proton transfer promoted by the coordination of protogenic Lewis bases to a Lewis acid is a critical step in catalytic transformations. Although the acidification of water upon coordination to a Lewis acid has been known for decades, no attempts have been made to correlate the Brønsted acidity of the coordinated water molecule with Lewis acid strength. To probe this effect, the pK a 's (estimated error of 1.3 pK a units) in acetonitrile of ten protogenic Lewis bases coordinated to seven Lewis acids containing Lewis acidities varying 70 kcal mol -1 , were computed. To quantify Lewis acid strength, the ability to transfer a hydride (hydride donor ability) from the respective main group hydride was used. Coordination of a Lewis acid to water increased the acidity of the bound water molecule between 20 and 50 pK a units. A linear correlation exhibiting a 2.6 pK a unit change of the Lewis acid-water adduct per ten kcal mol -1 change in hydride donor ability of the respective main group hydride was obtained. For the ten protogenic Lewis bases studied, the coordinated protogenic Lewis bases were acidified between 10 and 50 pK a units. On average, a ten kcal mol -1 change in hydride donor ability of the respective main group hydride resulted in about a 2.8 pK a unit change in the Brønsted acidity of the Lewis acid-Lewis base adducts. Since attempts to computationally investigate the pK a of main group dihydrogen complexes were unsuccessful, experimental determination of the first reported pK a of a main group dihydrogen complex is described. The pK a of H 2 -B(C 6 F 5 ) 3 was determined to be 5.8 ± 0.2 in acetonitrile.

Understanding Early Elementary Children's Conceptual Knowledge of Plant Structure and Function through Drawings

PubMed Central

Ellis, Jane P.; Jones, Alan M.

2014-01-01

This study examined children's drawings to explain children's conceptual understanding of plant structure and function. The study explored whether the children's drawings accurately reflect their conceptual understanding about plants in a manner that can be interpreted by others. Drawing, survey, interview, and observational data were collected from 182 students in grades K and 1 in rural southeastern United States. Results demonstrated the children held a wide range of conceptions concerning plant structure and function. These young children held very simple ideas about plants with respect to both their structure and function. Consistent with the drawings, the interviews presented similar findings. PMID:25185222

Artificial Hip Simulator with Crystal Models

NASA Image and Video Library

1966-06-21

Robert Johnson, top, sets the lubricant flow while Donald Buckley adjusts the bearing specimen on an artificial hip simulator at the National Aeronautics and Space Administration (NASA) Lewis Research Center. The simulator was supplemented by large crystal lattice models to demonstrate the composition of different bearing alloys. This this image by NASA photographer Paul Riedel was used for the cover of the August 15, 1966 edition of McGraw-Hill Product Engineering. Johnson was chief of Lubrication Branch and Buckley head of the Space Environment Lubrication Section in the Fluid System Components Division. In 1962 they began studying the molecular structure of metals. Their friction and wear testing revealed that the optimal structure for metal bearings was a hexagonal crystal structure with proper molecular space. Bearing manufacturers traditionally preferred cubic structures over hexagonal arrangements. Buckley and Johnson found that even though the hexagonal structural was not as inherently strong as its cubic counterpart, it was less likely to cause a catastrophic failure. The Lewis researchers concentrated their efforts on cobalt-molybdenum and titanium alloys for high temperatures applications. The alloys had a number of possible uses, included prosthetics. The alloys were similar in composition to the commercial alloys used for prosthetics, but employed the longer lasting hexagonal structure.

Development of a Lewis Base Catalyzed Selenocyclization Reaction

ERIC Educational Resources Information Center

Collins, William

2009-01-01

The concept of Lewis base activation of selenium Lewis acids has been effectively reduced to practice in the Lewis base catalyzed selenofunctionalization of unactivated olefins. In this reaction, the weakly acidic species, "N"-phenylselenyl succinimide, is cooperatively activated by the addition of a "soft" Lewis base donor (phosphine sulfides,…

The Use of C. S. Lewis's "Poems" for Oral Interpretation.

ERIC Educational Resources Information Center

Keefe, Carolyn

Suggestions are offered in this paper for adapting C. S. Lewis's poems for oral interpretation. A discussion of Lewis's lifelong correspondence with his friend Arthur Greeves provides insights into Lewis's perceptions of his own writing. Eighty poems selected from Lewis's "Poems" as appropriate for oral interpretation are classified…

157. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) ...

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

157. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) PLANS, SECTIONS, AND DETAILS FOR MST STATION 85.5, SHEET S90 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

224. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) ...

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

224. Photocopy of drawing (1963 structural drawing by General Dynamics/Astronautics) UMBILICAL MAST WIND DEFLECTOR REQUIRED FOR 206 PROGRAM, PAD, SHEET S-101 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Computational Elucidation of a Role That Brønsted Acidification of the Lewis Acid-Bound Water Might Play in the Hydrogenation of Carbonyl Compounds with H2 in Lewis Basic Solvents.

PubMed

Heshmat, Mojgan; Privalov, Timofei

2017-08-25

Brønsted acidification of water by Lewis acid (LA) complexation is one of the fundamental principles in chemistry. Using transition-state calculations (TS), herein we investigate the role that Brønsted acidification of the LA-bound water might play in the mechanism of the hydrogenation of carbonyl compounds in Lewis basic solvents under non-anhydrous conditions. The potential energy scans and TS calculations were carried out with a series of eight borane LAs as well as the commonly known strong LA AlCl 3 in 1,4-dioxane or THF as Lewis basic solvents. Our molecular model consists of the dative LA-water adduct with hydrogen bonds to acetone and a solvent molecule plus one additional solvent molecule that participates is the TS structure describing the cleavage of H 2 at acetone's carbonyl carbon atom. In all the molecular models applied here, acetone (O=CMe 2 ) is the archetypical carbonyl substrate. We demonstrate that Brønsted acidification of the LA-bound water can indeed lower the barrier height of the solvent-involving H 2 -cleavage at the acetone's carbonyl carbon atom. This is significant because at present it is believed that the mechanism of the herein considered reaction is described by the same mechanism regardless of whether the reaction conditions are strictly anhydrous or non-anhydrous. Our results offer an alternative to this belief that warrants consideration and further study. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The inner formal structure of the H-T-P drawings: an exploratory study.

PubMed

Vass, Z

1998-08-01

The study describes some interrelated patterns of traits of the House-Tree-Person (H-T-P) drawings with the instruments of hierarchical cluster analysis. First, according to the literature 1 7 formal or structural aspects of the projective drawings were collected, after which a detailed manual for coding was compiled. Second, the interrater reliability and the consistency of this manual was tested. Third, the hierarchical cluster structure of the reliable and consistent formal aspects was analysed. Results are: (a) a psychometrically tested coding manual of the investigated formal-structural aspects, each of them illustrated with drawings that showed the highest interrater agreement; and (b) the hierarchic cluster structure of the formal aspects of the H-T-P drawings of "normal" adults.

Membrane attack complex of complement is not essential for immune mediated demyelination in experimental autoimmune neuritis.

PubMed

Tran, Giang T; Hodgkinson, Suzanne J; Carter, Nicole M; Killingsworth, Murray; Nomura, Masaru; Verma, Nirupama D; Plain, Karren M; Boyd, Rochelle; Hall, Bruce M

2010-12-15

Antibody deposition and complement activation, especially membrane attack complex (MAC) formation are considered central for immune mediated demyelination. To examine the role of MAC in immune mediated demyelination, we studied experimental allergic neuritis (EAN) in Lewis rats deficient in complement component 6 (C6) that cannot form MAC. A C6 deficient Lewis (Lewis/C6-) strain of rats was bred by backcrossing the defective C6 gene, from PVG/C6- rats, onto the Lewis background. Lewis/C6- rats had the same C6 gene deletion as PVG/C6- rats and their sera did not support immune mediated haemolysis unless C6 was added. Active EAN was induced in Lewis and Lewis/C6- rats by immunization with bovine peripheral nerve myelin in complete Freund's adjuvant (CFA), and Lewis/C6- rats had delayed clinical EAN compared to the Lewis rats. Peripheral nerve demyelination in Lewis/C6- was also delayed but was similar in extent at the peak of disease. Compared to Lewis, Lewis/C6- nerves had no MAC deposition, reduced macrophage infiltrate and IL-17A, but similar T cell infiltrate and Th1 cytokine mRNA expression. ICAM-1 and P-selectin mRNA expression and immunostaining on vascular endothelium were delayed in Lewis C6- compared to Lewis rats' nerves. This study found that MAC was not required for immune mediated demyelination; but that MAC enhanced early symptoms and early demyelination in EAN, either by direct lysis or by sub-lytic induction of vascular endothelial expression of ICAM-1 and P-selectin. Copyright © 2010 Elsevier B.V. All rights reserved.

Impairments of speech fluency in Lewy body spectrum disorder.

PubMed

Ash, Sharon; McMillan, Corey; Gross, Rachel G; Cook, Philip; Gunawardena, Delani; Morgan, Brianna; Boller, Ashley; Siderowf, Andrew; Grossman, Murray

2012-03-01

Few studies have examined connected speech in demented and non-demented patients with Parkinson's disease (PD). We assessed the speech production of 35 patients with Lewy body spectrum disorder (LBSD), including non-demented PD patients, patients with PD dementia (PDD), and patients with dementia with Lewy bodies (DLB), in a semi-structured narrative speech sample in order to characterize impairments of speech fluency and to determine the factors contributing to reduced speech fluency in these patients. Both demented and non-demented PD patients exhibited reduced speech fluency, characterized by reduced overall speech rate and long pauses between sentences. Reduced speech rate in LBSD correlated with measures of between-utterance pauses, executive functioning, and grammatical comprehension. Regression analyses related non-fluent speech, grammatical difficulty, and executive difficulty to atrophy in frontal brain regions. These findings indicate that multiple factors contribute to slowed speech in LBSD, and this is mediated in part by disease in frontal brain regions. Copyright © 2011 Elsevier Inc. All rights reserved.

Newly Acquired Gulfstream C-131B Samaritan in the Hangar

NASA Image and Video Library

1976-11-21

The National Aeronautics and Space Administration (NASA) Lewis Research Center acquired this Gulfstream C-131B Samaritan from the Air Force in July 1976. The center obtained the aircraft to support its current earth resources work. The C-131B is seen here inside the Lewis hangar being refurbished and converted into a flying laboratory. The modifications were led by Lewis Chief of Flight Operations Robert Hogan. The cockpit and cabin were modified and packed with instrumentation. The new equipment included Sideways Looking Airborne Radar (SLAR), geothermal sensors, radar antennas, and an inertial navigation system. In addition, portals were installed underneath the fuselage for cameras and remote sensing equipment. NASA’s C-131B was used to support researchers tracking ice flows on the Great Lakes and in Prudhoe Bay, Alaska. It was also used for the center’s program to determine heating losses in the Cleveland area’s residential and commercial structures. The aircraft was later donated to the University of Georgia.

6. Photocopy of drawing (1976 structural drawing by the Space ...

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

6. Photocopy of drawing (1976 structural drawing by the Space and Missile Test Center, VAFB, USAF) FLOOR PLAN, ELEVATIONS, SECTIONS, AND DETAILS FOR THE PYROTEST AND STORAGE BUILDING, SHEET S22 - Vandenberg Air Force Base, Space Launch Complex 3, Pyrotechnic Shed, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

198. Photocopy of drawing (1976 structural drawing by the Space ...

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

198. Photocopy of drawing (1976 structural drawing by the Space and Missile Test Center, VAFB, USAF) FIRE RESISTIVE COATING PLAN AND ELEVATION FOR THE MST, SHEET S25 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

273. Photocopy of drawing (1976 structural drawing by the Space ...

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

273. Photocopy of drawing (1976 structural drawing by the Space and Missile Test Center, VAFB, USAF) PLANS, ELEVATIONS, AND DETAILS OF THE CAMERA TOWERS, SHEET S20 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

277. Photocopy of drawing (1979 structural drawing by StearnsRoger Incorporated) ...

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

277. Photocopy of drawing (1979 structural drawing by Stearns-Roger Incorporated) PLANS AND SECTIONS FOR THE TIROS AND NOAA THEODOLITE STATION, SHEET 511-S-62 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

21. Photocopy of drawing (1977 structural drawing by StearnsRoger Incorporated) ...

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

21. Photocopy of drawing (1977 structural drawing by Stearns-Roger Incorporated) TWO-TON CAPACITY BRIDGE CRANE PLANS AND SECTIONS FOR VEHICLE SUPPORT BUILDING, SHEET 511-533 - Vandenberg Air Force Base, Space Launch Complex 3, Vehicle Support Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Understanding Early Elementary Children's Conceptual Knowledge of Plant Structure and Function through Drawings

ERIC Educational Resources Information Center

Anderson, Janice L.; Ellis, Jane P.; Jones, Alan M.

2014-01-01

This study examined children's drawings to explain children's conceptual understanding of plant structure and function. The study explored whether the children's drawings accurately reflect their conceptual understanding about plants in a manner that can be interpreted by others. Drawing, survey, interview, and observational data were collected…

Drawing skill is related to the efficiency of encoding object structure.

PubMed

Perdreau, Florian; Cavanagh, Patrick

2014-01-01

Accurate drawing calls on many skills beyond simple motor coordination. A good internal representation of the target object's structure is necessary to capture its proportion and shape in the drawing. Here, we assess two aspects of the perception of object structure and relate them to participants' drawing accuracy. First, we assessed drawing accuracy by computing the geometrical dissimilarity of their drawing to the target object. We then used two tasks to evaluate the efficiency of encoding object structure. First, to examine the rate of temporal encoding, we varied presentation duration of a possible versus impossible test object in the fovea using two different test sizes (8° and 28°). More skilled participants were faster at encoding an object's structure, but this difference was not affected by image size. A control experiment showed that participants skilled in drawing did not have a general advantage that might have explained their faster processing for object structure. Second, to measure the critical image size for accurate classification in the periphery, we varied image size with possible versus impossible object tests centered at two different eccentricities (3° and 8°). More skilled participants were able to categorise object structure at smaller sizes, and this advantage did not change with eccentricity. A control experiment showed that the result could not be attributed to differences in visual acuity, leaving attentional resolution as a possible explanation. Overall, we conclude that drawing accuracy is related to faster encoding of object structure and better access to crowded details.

Drawing skill is related to the efficiency of encoding object structure

PubMed Central

Perdreau, Florian; Cavanagh, Patrick

2014-01-01

Accurate drawing calls on many skills beyond simple motor coordination. A good internal representation of the target object's structure is necessary to capture its proportion and shape in the drawing. Here, we assess two aspects of the perception of object structure and relate them to participants' drawing accuracy. First, we assessed drawing accuracy by computing the geometrical dissimilarity of their drawing to the target object. We then used two tasks to evaluate the efficiency of encoding object structure. First, to examine the rate of temporal encoding, we varied presentation duration of a possible versus impossible test object in the fovea using two different test sizes (8° and 28°). More skilled participants were faster at encoding an object's structure, but this difference was not affected by image size. A control experiment showed that participants skilled in drawing did not have a general advantage that might have explained their faster processing for object structure. Second, to measure the critical image size for accurate classification in the periphery, we varied image size with possible versus impossible object tests centered at two different eccentricities (3° and 8°). More skilled participants were able to categorise object structure at smaller sizes, and this advantage did not change with eccentricity. A control experiment showed that the result could not be attributed to differences in visual acuity, leaving attentional resolution as a possible explanation. Overall, we conclude that drawing accuracy is related to faster encoding of object structure and better access to crowded details. PMID:25469216

Looking beyond Lewis Structures: A General Chemistry Molecular Modeling Experiment Focusing on Physical Properties and Geometry

ERIC Educational Resources Information Center

Linenberger, Kimberly J.; Cole, Renee S.; Sarkar, Somnath

2011-01-01

We present a guided-inquiry experiment using Spartan Student Version, ready to be adapted and implemented into a general chemistry laboratory course. The experiment provides students an experience with Spartan Molecular Modeling software while discovering the relationships between the structure and properties of molecules. Topics discussed within…

Introducing NMR to a General Chemistry Audience: A Structural-Based Instrumental Laboratory Relating Lewis Structures, Molecular Models, and [superscript 13]C NMR Data

ERIC Educational Resources Information Center

Pulliam, Curtis R.; Pfeiffer, William F.; Thomas, Alyssa C.

2015-01-01

This paper describes a first-year general chemistry laboratory that uses NMR spectroscopy and model building to emphasize molecular shape and structure. It is appropriate for either a traditional or an atoms-first curriculum. Students learn the basis of structure and the use of NMR data through a cooperative learning hands-on laboratory…

Activities of the Structures Division, Lewis Research Center

NASA Technical Reports Server (NTRS)

1990-01-01

The purpose of the NASA Lewis Research Center, Structures Division's 1990 Annual Report is to give a brief, but comprehensive, review of the technical accomplishments of the Division during the past calendar year. The report is organized topically to match the Center's Strategic Plan. Over the years, the Structures Division has developed the technology base necessary for improving the future of aeronautical and space propulsion systems. In the future, propulsion systems will need to be lighter, to operate at higher temperatures and to be more reliable in order to achieve higher performance. Achieving these goals is complex and challenging. Our approach has been to work cooperatively with both industry and universities to develop the technology necessary for state-of-the-art advancement in aeronautical and space propulsion systems. The Structures Division consists of four branches: Structural Mechanics, Fatigue and Fracture, Structural Dynamics, and Structural Integrity. This publication describes the work of the four branches by three topic areas of Research: (1) Basic Discipline; (2) Aeropropulsion; and (3) Space Propulsion. Each topic area is further divided into the following: (1) Materials; (2) Structural Mechanics; (3) Life Prediction; (4) Instruments, Controls, and Testing Techniques; and (5) Mechanisms. The publication covers 78 separate topics with a bibliography containing 159 citations. We hope you will find the publication interesting as well as useful.

Maxima of |Ψ|2: a connection between quantum mechanics and Lewis structures.

PubMed

Lüchow, Arne

2014-04-30

The maxima of squared electronic wave functions |Ψ|2 are analyzed for a number of small molecules. They are in principle observables and show considerable chemical insight from first principles. The maxima contain substantial information about the relative electron positions in a molecule, such as the pairing of opposite spin electrons and the Pauli repulsion which are lost in the electron density. Single bond and double bond as well as polar bond pairs and lone pairs are obtained from the maximum analysis. In many cases, we find a correspondence to the electron arrangements in molecules as assumed by Lewis in 1916. Copyright © 2014 Wiley Periodicals, Inc.

KvN mechanics approach to the time-dependent frequency harmonic oscillator.

PubMed

Ramos-Prieto, Irán; Urzúa-Pineda, Alejandro R; Soto-Eguibar, Francisco; Moya-Cessa, Héctor M

2018-05-30

Using the Ermakov-Lewis invariants appearing in KvN mechanics, the time-dependent frequency harmonic oscillator is studied. The analysis builds upon the operational dynamical model, from which it is possible to infer quantum or classical dynamics; thus, the mathematical structure governing the evolution will be the same in both cases. The Liouville operator associated with the time-dependent frequency harmonic oscillator can be transformed using an Ermakov-Lewis invariant, which is also time dependent and commutes with itself at any time. Finally, because the solution of the Ermakov equation is involved in the evolution of the classical state vector, we explore some analytical and numerical solutions.

John Lewis | NREL

Science.gov Websites

Lewis John Lewis John Lewis Researcher IV-Chemical Engineering John.Lewis@nrel.gov | 303-275-3021 Education Ph.D. Chemical Engineering, California Institute of Technology, Pasadena, CA, 1996 M.S. Chemical Engineering, California Institute of Technology, Pasadena, CA, 1993 B.S. Chemical Engineering, Texas A&M

78 FR 48315 - Drawbridge Operation Regulation; Lewis and Clark River, Astoria, OR

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-08

... Operation Regulation; Lewis and Clark River, Astoria, OR AGENCY: Coast Guard, DHS. ACTION: Notice of... operating schedule that governs the Lewis and Clark Bridge which crosses the Lewis and Clark River, mile 1.0... Transportation has requested that the Lewis and Clark Drawbridge, mile 1.0, remain in the closed position and not...

Computational studies of complexation of nitrous oxide by borane-phosphine frustrated Lewis pairs.

PubMed

Gilbert, Thomas M

2012-08-14

Computational studies of complexes Ar(3)B-ONN-PR(3) derived from reactions between borane-phosphine frustrated Lewis pairs and N(2)O reveal several interesting facets. Natural resonance theory calculations support a change in the preferred resonance structure as the Lewis acidity of the borane increases. Potential constitutional isomers where phosphorus binds to oxygen and boron to nitrogen are predicted to be unstable with respect to loss of phosphine oxide and free N(2). Other constitutional isomers represent stationary points on the potential energy surface; most are considerably less stable than the observed complexes, but one is predicted to be as stable. This arises because the dominant resonance form combines alternating charge with the presence of a stabilizing NO double bond. The relationship between Lewis acidity and complex formation for a variety of boranes was explored; the results are consistent with the idea that greater Lewis acidity stabilizes both classical and frustrated Lewis acid-base pairs, but to differing degrees such that both types can entrap N(2)O. Calculations addressing the mechanism of complex formation suggest that N(2)O binds first through the nitrogen to the phosphine phosphorus of the FLP, whereupon boron coordinates the oxygen atom. Studies of the mechanism of the degenerate exchange reaction between (4-F-H(4)C(6))(3)B-ONN-P(t-Bu)(3) and B(C(6)H(4)-4-F)(3), involves a "transition state", with relatively short B-O distances, and so resembles a classical I(a) process. The process involves two barriers, one associated with bringing the incoming borane into proximity with the oxygen, and the other associated with isomerising from a ladle-shaped cis-trans ct conformer to the observed trans-trans tt-type structure. The overall barrier for degenerate exchange was predicted to be between 65 and 110 kJ mol(-1), in fair agreement with experiment. Similar studies of the reaction between (4-F-H(4)C(6))(3)B-ONN-P(t-Bu)(3) and B(C(6)F(5))(3) indicate that this process more closely resembles a classical I(d) process, in that the "transition state" involves long B-O distances. Derivatization of the complexed NNO fragment appears possible; interaction between (F(5)C(6))(3)B-ONN-P(t-Bu)(3) and MeLi suggests stability for the ion pairs (F(5)C(6))(3)B-ON(Me)N-P(t-Bu)(3)(-)/Li(+) and (F(5)C(6))(3)B-ONN(Me)-P(t-Bu)(3)(-)/Li(+).

Bridging the Gap between Structures and Properties: An Investigation and Evaluation of Students' Representational Competence

ERIC Educational Resources Information Center

Underwood, Sonia Miller

2011-01-01

The heart of learning chemistry is the ability to connect a compound's structure to its function; Lewis structures provide an essential link in this process. In many cases, their construction is taught using an algorithmic approach, containing a set of step-by-step rules. We believe that this approach is in direct conflict with the precepts of…

Lipopolysaccharide Structure and Biosynthesis in Helicobacter pylori.

PubMed

Li, Hong; Liao, Tingting; Debowski, Aleksandra W; Tang, Hong; Nilsson, Hans-Olof; Stubbs, Keith A; Marshall, Barry J; Benghezal, Mohammed

2016-12-01

This review covers the current knowledge and gaps in Helicobacter pylori lipopolysaccharide (LPS) structure and biosynthesis. H. pylori is a Gram-negative bacterium which colonizes the luminal surface of the human gastric epithelium. Both a constitutive alteration of the lipid A preventing TLR4 elicitation and host mimicry of the Lewis antigen decorated O-antigen of H. pylori LPS promote immune escape and chronic infection. To date, the complete structure of H. pylori LPS is not available, and the proposed model is a linear arrangement composed of the inner core defined as the hexa-saccharide (Kdo-LD-Hep-LD-Hep-DD-Hep-Gal-Glc), the outer core composed of a conserved trisaccharide (-GlcNAc-Fuc-DD-Hep-) linked to the third heptose of the inner core, the glucan, the heptan and a variable O-antigen, generally consisting of a poly-LacNAc decorated with Lewis antigens. Although the glycosyltransferases (GTs) responsible for the biosynthesis of the H. pylori O-antigen chains have been identified and characterized, there are many gaps in regard to the biosynthesis of the core LPS. These limitations warrant additional mutagenesis and structural studies to obtain the complete LPS structure and corresponding biosynthetic pathway of this important gastric bacterium. © 2016 John Wiley & Sons Ltd.

Structure of Flame Balls at Low Lewis-Number (SOFBALL): Preliminary Results From the STS-83 and STS-94 Space Flight Experiments

NASA Technical Reports Server (NTRS)

Ronney, Paul D.; Wu, Ming-Shin; Pearlman, Howard G.; Weiland, Karen J.

1998-01-01

Results from the Structure Of Flame Balls At Low Lewis-number (SOFBALL) space flight experiment conducted on the MSL-1 Space Shuttle missions are reported. Several new insights were obtained, including: much lower buoyancy-induced drift speed than anticipated pre-flight; repulsion of adjacent flame balls due to their mutual interaction; remarkable sensitivity of flame balls to small accelerations resulting from Orbiter attitude control maneuvers; and very similar net heat release for all flame balls in all mixtures tested. Comparison of experimental results to computational predictions reveals limitations in current models of H2-02 chemistry for very lean mixtures. It is discussed how the results of these space experiments may provide an improved understanding of the interactions of the two most important phenomena in combusting materials, namely chemical reaction and transport processes, in the unequivocally simplest possible configuration.

Modern Exploration of the Lewis and Clark Expedition

NASA Technical Reports Server (NTRS)

2006-01-01

The Lewis and Clark Geosystem is an online collection of private, state, local, and Federal data resources associated with the geography of the Lewis and Clark Expedition. Data were compiled from key partners including NASA s Stennis Space Center, the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, the U.S. Geological Survey (USGS), the University of Montana, the U.S. Department of Agriculture Forest Service, and from a collection of Lewis and Clark scholars. It combines modern views of the landscape with historical aerial photography, cartography, and other geographical data resources and historical sources, including: The Journals of the Lewis and Clark Expedition, the Academy of Natural Science's Lewis and Clark Herbarium, high-resolution copies of the American Philosophical Society s primary-source Lewis and Clark Journals, The Library of Congress Lewis and Clark cartography collection, as well as artifacts from the Smithsonian Institution and other sources.

53. Photocopy of Structural drawing, dated August 6, 1976 by ...

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

53. Photocopy of Structural drawing, dated August 6, 1976 by Raytheon Company. Original drawing property of United States Air Force, 21" Space Command. S-4 - PAVE PAWS TECHNICAL FACILITY - OTIS AFB - FIRST FLOOR PLAN. DRAWING NO. AW35-46-06 - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

55. Photocopy of Structural drawing, dated August 6, 1976 by ...

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

55. Photocopy of Structural drawing, dated August 6, 1976 by Raytheon Company. Original drawing property of United States Air Force, 21" Space Command. S-15 - PAVE PAWS TECHNICAL FACILITY - OTIS AFB - UTILITY BUILDING. DRAWING NO. AW35-46-06 - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

54. Photocopy of Structural drawing, dated August 6, 1976 by ...

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

54. Photocopy of Structural drawing, dated August 6, 1976 by Raytheon Company. Original drawing property of United States Air Force, 21" Space Command. S-14 - PAVE PAWS TECHNICAL FACILITY - OTIS AFB - ARRAY DETAILS. DRAWING NO. AW35-46-06 - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA

278. Photocopy of drawing (1978 structural electrical drawing by the ...

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

278. Photocopy of drawing (1978 structural electrical drawing by the Space and Missile Test Center, VAFB, USAF) DETAILS, SECTION, AND ELECTRICAL PLAN FOR THE TIROS AND NOAA THEODOLITE STATION, SLC-3E, SHEET 4 OF 4 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Structure A, steel shelving. Drawing no. H3300. Original drawing by ...

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

Structure A, steel shelving. Drawing no. H3-300. Original drawing by Black & Veatch, Consulting Engineers, Kansas City, Missouri, prepared for the U.S. Department of the Army, Office of Engineers, Military Construction Division, Washington D.C. dated November 5, 1951. - Travis Air Force Base, Building No. 925, W Street, Fairfield, Solano County, CA

Design, fabrication and test of prototype furnace for continuous growth of wide silicon ribbon

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.

1976-01-01

A program having the overall objective of growing wide, thin silicon dendritic web crystals quasi-continuously from a semi-automated facility is discussed. The design considerations and fabrication of the facility as well as the test and operation phase are covered; detailed engineering drawings are included as an appendix. During the test and operation phase of the program, more than eighty growth runs and numerous thermal test runs were performed. At the conclusion of the program, 2.4 cm wide web was being grown at thicknesses of 100 to 300 micrometers. As expected, the thickness and growth rate are closely related. Solar cells made from this material were tested at NASA-Lewis and found to have conversion efficiencies comparable to devices fabricated from Czochralski material.

Diverse Narrative Structures in Contemporary Picturebooks: Opportunities for Children's Meaning-Making

ERIC Educational Resources Information Center

Pantaleo, Sylvia; Sipe, Lawrence R.

2012-01-01

In this article, the authors situate their discussion of diverse narrative structures in the context of oral storytelling practices and postmodern picturebooks. They focus on three contemporary picturebooks: "Don't Read This Book!" (Lewis, 2009), "Abe Lincoln Crosses a Creek: A Tall Thin Tale" (Hopkins, 2008), and "The Stinky Cheese Man and Other…

A periodic DFT study of ammonia adsorption on the V2O5 (001), V2O5 (010) and V2O5 (100) surfaces: Lewis versus Brönsted acid sites

NASA Astrophysics Data System (ADS)

Yao, Huichao; Chen, Yu; Wei, Yuechang; Zhao, Zhen; Liu, Zhichang; Xu, Chunming

2012-11-01

The adsorption of ammonia at Brönsted and Lewis acid sites on three low-index (001), (010) and (100) surfaces of V2O5 catalyst was investigated using density functional theory (DFT) method. Three levels of surface relaxation periodic models including top single layer relaxation (S-model), moderately deeper relaxation (M-model) and full relaxation model (F-model) were applied to examine the effect of the surface relaxation on the binding structures and adsorption energies. The results of calculations showed that on the saturated basal plane V2O5 (001), ammonia adsorption at the Brönsted acid sites (VOH) is energetically more favorable. On unsaturated (010) and (100) surfaces, ammonia is adsorbed strongly on both Brönsted (VOH) and Lewis acid sites (V). Surface relaxations have no influence on ammonia adsorption on saturated (001) surface, while a strong dependence on the relaxation models is observed for NH3-adsorption energies on (010) and (100) surfaces, especially at the Lewis acid sites of both side planes. When complete relaxation considered (F-model), ammonia adsorption on the Lewis acid sites (V) dominates for side planes (010) and (100). In the presence of VOH as neighbor, the ammonia adsorption at V sites is however weakened significantly due to steric hindrance. Hydrogen bonds may play a role, although not determining one, in the respect of the adsorption of ammonia on (010) and (100) surfaces. Moderate relaxation and full relaxation are absolutely necessary for the description of both H and NH3 adsorption on unsaturated (100) and (010) surfaces, respectively.

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1988-01-01

The computational structural mechanics (CSM) program at Lewis encompasses the formulation and solution of structural mechanics problems and the development of integrated software systems to computationally simulate the performance, durability, and life of engine structures. It is structured to supplement, complement, and, whenever possible, replace costly experimental efforts. Specific objectives are to investigate unique advantages of parallel and multiprocessing for reformulating and solving structural mechanics and formulating and solving multidisciplinary mechanics and to develop integrated structural system computational simulators for predicting structural performance, evaluating newly developed methods, and identifying and prioritizing improved or missing methods.

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1989-01-01

The computational structural mechanics (CSM) program at Lewis encompasses the formulation and solution of structural mechanics problems and the development of integrated software systems to computationally simulate the performance, durability, and life of engine structures. It is structured to supplement, complement, and, whenever possible, replace costly experimental efforts. Specific objectives are to investigate unique advantages of parallel and multiprocessing for reformulating and solving structural mechanics and formulating and solving multidisciplinary mechanics and to develop integrated structural system computational simulators for predicting structural performance, evaluating newly developed methods, and identifying and prioritizing improved or missing methods.

Clinical Features of Alzheimer Disease With and Without Lewy Bodies.

PubMed

Chung, Eun Joo; Babulal, Ganesh M; Monsell, Sarah E; Cairns, Nigel J; Roe, Catherine M; Morris, John C

2015-07-01

Lewy bodies are a frequent coexisting pathology in late-onset Alzheimer disease (AD). Previous studies have examined the contribution of Lewy bodies to the clinical phenotype of late-onset AD with variable findings. To determine whether the presence of Lewy body pathology influences the clinical phenotype and progression of symptoms in longitudinally assessed participants with AD. Retrospective clinical and pathological cohort study of 531 deceased participants who met the neuropathologic criteria for intermediate or high likelihood of AD according to the National Institute on Aging-Ronald Reagan Institute guidelines for the neuropathologic diagnosis of AD. All participants had a clinical assessment within 2 years of death. The data were obtained from 34 AD centers maintained by the National Alzheimer Coordinating Center and spanned from September 12, 2005, to April 30, 2013. Standardized neuropathologic assessment and then brain autopsy after death. Clinical and neuropsychiatric test scores. The mean (SD) age at death was statistically significantly younger for participants who had AD with Lewy bodies (77.9 [9.5] years) than for participants who had AD without Lewy bodies (80.2 [11.1] years) (P = .01). The mean (SD) age at onset of dementia symptoms was also younger for participants who had AD with Lewy bodies (70.0 [9.9] years) than for participants who had AD without Lewy bodies (72.2 [12.3] years) (P = .03). More men than women had AD with Lewy bodies (P = .01). The frequency of having at least 1 APOE ε4 allele was higher for participants who had AD with Lewy bodies than for participants who had AD without Lewy bodies (P = .03). After adjusting for age, sex, education, frequency of plaques (neuritic and diffuse), and tangle stage, we found that participants who had AD with Lewy bodies had a statistically significantly higher mean (SD) Neuropsychiatric Inventory Questionnaire score (6.59 [1.44] [95% CI, 3.75-9.42] vs 5.49 [1.39] [95% CI, 2.76-8.23]; P = .04) and a statistically significantly higher mean (SD) Unified Parkinson Disease Rating Scale motor score (0.81 [0.18] [95% CI, 0.45-1.17] vs 0.54 [0.18] [95% CI, 0.19-0.88]; P < .001) than did participants who had AD without Lewy bodies. Participants with both AD and Lewy body pathology have a clinical phenotype that may be distinguished from AD alone. The frequency of Lewy bodies in AD and the association of Lewy bodies with the APOE ε4 allele suggest potential common mechanisms for AD and Lewy body pathologies.

Aerial View of NACA's Lewis Flight Propulsion Research Laboratory

NASA Image and Video Library

1946-05-21

The National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory in Cleveland, Ohio as seen from the west in May 1946. The Cleveland Municipal Airport is located directly behind. The laboratory was built in the early 1940s to resolve problems associated with aircraft engines. The initial campus contained seven principal buildings: the Engine Research Building, hangar, Fuels and Lubricants Building, Administration Building, Engine Propeller Research Building, Altitude Wind Tunnel, and Icing Research Tunnel. These facilities and their associated support structures were located within an area occupying approximately one-third of the NACA’s property. After World War II ended, the NACA began adding new facilities to address different problems associated with the newer, more powerful engines and high speed flight. Between 1946 and 1955, four new world-class test facilities were built: the 8- by 6-Foot Supersonic Wind Tunnel, the Propulsion Systems Laboratory, the Rocket Engine Test Facility, and the 10- by 10-Foot Supersonic Wind Tunnel. These large facilities occupied the remainder of the NACA’s semicircular property. The Lewis laboratory expanded again in the late 1950s and early 1960s as the space program commenced. Lewis purchased additional land in areas adjacent to the original laboratory and acquired a large 9000-acre site located 60 miles to the west in Sandusky, Ohio. The new site became known as Plum Brook Station.

Surface functionalization of two-dimensional metal chalcogenides by Lewis acid-base chemistry

NASA Astrophysics Data System (ADS)

Lei, Sidong; Wang, Xifan; Li, Bo; Kang, Jiahao; He, Yongmin; George, Antony; Ge, Liehui; Gong, Yongji; Dong, Pei; Jin, Zehua; Brunetto, Gustavo; Chen, Weibing; Lin, Zuan-Tao; Baines, Robert; Galvão, Douglas S.; Lou, Jun; Barrera, Enrique; Banerjee, Kaustav; Vajtai, Robert; Ajayan, Pulickel

2016-05-01

Precise control of the electronic surface states of two-dimensional (2D) materials could improve their versatility and widen their applicability in electronics and sensing. To this end, chemical surface functionalization has been used to adjust the electronic properties of 2D materials. So far, however, chemical functionalization has relied on lattice defects and physisorption methods that inevitably modify the topological characteristics of the atomic layers. Here we make use of the lone pair electrons found in most of 2D metal chalcogenides and report a functionalization method via a Lewis acid-base reaction that does not alter the host structure. Atomic layers of n-type InSe react with Ti4+ to form planar p-type [Ti4+n(InSe)] coordination complexes. Using this strategy, we fabricate planar p-n junctions on 2D InSe with improved rectification and photovoltaic properties, without requiring heterostructure growth procedures or device fabrication processes. We also show that this functionalization approach works with other Lewis acids (such as B3+, Al3+ and Sn4+) and can be applied to other 2D materials (for example MoS2, MoSe2). Finally, we show that it is possible to use Lewis acid-base chemistry as a bridge to connect molecules to 2D atomic layers and fabricate a proof-of-principle dye-sensitized photosensing device.

Surveyor Atlas-Centaur Shroud Venting Structural Test in the Space Power Chambers

NASA Image and Video Library

1967-06-21

Setup of a Surveyor/Atlas/Centaur shroud in the Space Power Chambers for a leak test at the National Aeronautics and Space Administration (NASA) Lewis Research Center. Centaur was a 15,000-pound thrust second-stage rocket designed for the military in 1957 and 1958 by General Dynamics. It was the first major rocket to use the liquid hydrogen technology developed by Lewis in the 1950s. The Centaur Program suffered numerous problems before being transferred to Lewis in 1962. Several test facilities at Lewis’ main campus and Plum Brook Station were built or modified specifically for Centaur, including the Space Power Chambers. In 1961, NASA Lewis management decided to convert its Altitude Wind Tunnel into two large test chambers and later renamed it the Space Power Chambers. The conversion, which took over 2 years, included the removal of the tunnel’s internal components and insertion of bulkheads to seal off the new chambers. The larger chamber, seen here, could simulate altitudes of 100,000 feet. It was used for Centaur shroud separation and propellant management studies until the early 1970s. The leak test in this photograph was likely an attempt to verify that the shroud’s honeycomb shell did not seep any of its internal air when the chamber was evacuated to pressures similar to those found in the upper atmosphere.

Hypersonic transport aircraft

NASA Technical Reports Server (NTRS)

1987-01-01

A hypersonic transport aircraft design project was selected as a result of interactions with NASA Lewis Research Center personnel and fits the Presidential concept of the Orient Express. The Graduate Teaching Assistant (GTA) and an undergraduate student worked at the NASA Lewis Research Center during the 1986 summer conducting a literature survey, and relevant literature and useful software were collected. The computer software was implemented in the Computer Aided Design Laboratory of the Mechanical and Aerospace Engineering Department. In addition to the lectures by the three instructors, a series of guest lectures was conducted. The first of these lectures 'Anywhere in the World in Two Hours' was delivered by R. Luidens of NASA Lewis Center. In addition, videotaped copies of relevant seminars obtained from NASA Lewis were also featured. The first assignment was to individually research and develop the mission requirements and to discuss the findings with the class. The class in consultation with the instructors then developed a set of unified mission requirements. Then the class was divided into three design groups (1) Aerodynamics Group, (2) Propulsion Group, and (3) Structures and Thermal Analyses Group. The groups worked on their respective design areas and interacted with each other to finally come up with an integrated conceptual design. The three faculty members and the GTA acted as the resource persons for the three groups and aided in the integration of the individual group designs into the final design of a hypersonic aircraft.

Progress in materials and structures at Lewis Research Center

NASA Technical Reports Server (NTRS)

Glasgow, T. K.; Lauver, R. W.; Halford, G. R.; Davies, R. L.

1980-01-01

The development of power and propulsion system technology is discussed. Specific emphasis is placed on the following: high temperature materials; composite materials; advanced design and life prediction; and nondestructive evaluation. Future areas of research are also discussed.

Geology, sequence stratigraphy, and oil and gas assessment of the Lewis Shale Total Petroleum System, San Juan Basin, New Mexico and Colorado: Chapter 5 in Total petroleum systems and geologic assessment of undiscovered oil and gas resources in the San Juan Basin Province, exclusive of Paleozoic rocks, New Mexico and Colorado

USGS Publications Warehouse

Dubiel, R.F.

2013-01-01

The Lewis Shale Total Petroleum System (TPS) in the San Juan Basin Province contains a continuous gas accumulation in three distinct stratigraphic units deposited in genetically related depositional environments: offshore-marine shales, mudstones, siltstones, and sandstones of the Lewis Shale, and marginal-marine shoreface sandstones and siltstones of both the La Ventana Tongue and the Chacra Tongue of the Cliff House Sandstone. The Lewis Shale was not a completion target in the San Juan Basin (SJB) in early drilling from about the 1950s through 1990. During that time, only 16 wells were completed in the Lewis from natural fracture systems encountered while drilling for deeper reservoir objectives. In 1991, existing wells that penetrated the Lewis Shale were re-entered by petroleum industry operators in order to fracture-stimulate the Lewis and to add Lewis gas production onto preexisting, and presumably often declining, Mesaverde Group production stratigraphically lower in the section. By 1997, approximately 101 Lewis completions had been made, both as re-entries into existing wells and as add-ons to Mesaverde production in new wells. Based on recent industry drilling and completion practices leading to successful gas production from the Lewis and because new geologic models indicate that the Lewis Shale contains both source rocks and reservoir rocks, the Lewis Shale TPS was defined and evaluated as part of this U.S. Geological Survey oil and gas assessment of the San Juan Basin. Gas in the Lewis Shale Total Petroleum System is produced from shoreface sandstones and siltstones in the La Ventana and Chacra Tongues and from distal facies of these prograding clastic units that extend into marine rocks of the Lewis Shale in the central part of the San Juan Basin. Reservoirs are in shoreface sandstone parasequences of the La Ventana and Chacra and their correlative distal parasequences in the Lewis Shale where both natural and artificially enhanced fractures produce gas. The Lewis Continuous Gas Assessment Unit (AU 50220261) is thought to be self-sourced from and self-sealed by marine shales and mudstones deposited within the Lewis Shale that enclose clastic parasequences in the La Ventana and Chacra Tongues. The gas resource is thought to be a continuous accumulation sourced from the Lewis Shale throughout the depositional basin. In the Lewis Continuous Gas Assessment Unit (AU 50220261), for continuous gas resources, there is an F95 of 8,315.22 billion cubic feet of gas (BCFG) and an F5 of 12,282.31 BCFG, with a mean value of 10,177.24 BCFG. There is an F95 of 18.08 million barrels of natural gas liquids (MMBNGL) and an F5 of 47.32 MMBNGL, with a mean of 30.53 MMBNGL.

Differentiating between visual hallucination-free dementia with Lewy bodies and corticobasal syndrome on the basis of neuropsychology and perfusion single-photon emission computed tomography.

PubMed

Misch, Michael R; Mitchell, Sara; Francis, Philip L; Sherborn, Kayla; Meradje, Katayoun; McNeely, Alicia A; Honjo, Kie; Zhao, Jiali; Scott, Christopher Jm; Caldwell, Curtis B; Ehrlich, Lisa; Shammi, Prathiba; MacIntosh, Bradley J; Bilbao, Juan M; Lang, Anthony E; Black, Sandra E; Masellis, Mario

2014-01-01

Dementia with Lewy bodies (DLB) and Corticobasal Syndrome (CBS) are atypical parkinsonian disorders with fronto-subcortical and posterior cognitive dysfunction as common features. While visual hallucinations are a good predictor of Lewy body pathology and are rare in CBS, they are not exhibited in all cases of DLB. Given the clinical overlap between these disorders, neuropsychological and imaging markers may aid in distinguishing these entities. Prospectively recruited case-control cohorts of CBS (n =31) and visual hallucination-free DLB (n =30), completed neuropsychological and neuropsychiatric measures as well as brain perfusion single-photon emission computed tomography and structural magnetic resonance imaging (MRI). Perfusion data were available for forty-two controls. Behavioural, perfusion, and cortical volume and thickness measures were compared between the groups to identify features that serve to differentiate them. The Lewy body with no hallucinations group performed more poorly on measures of episodic memory compared to the corticobasal group, including the delayed and cued recall portions of the California Verbal Learning Test (F (1, 42) =23.1, P <0.001 and F (1, 42) =14.0, P =0.001 respectively) and the delayed visual reproduction of the Wechsler Memory Scale-Revised (F (1, 36) =9.7, P =0.004). The Lewy body group also demonstrated reduced perfusion in the left occipital pole compared to the corticobasal group (F (1,57) =7.4, P =0.009). At autopsy, the Lewy body cases all demonstrated mixed dementia with Lewy bodies, Alzheimer's disease and small vessel arteriosclerosis, while the corticobasal cases demonstrated classical corticobasal degeneration in five, dementia with agyrophilic grains + corticobasal degeneration + cerebral amyloid angiopathy in one, Progressive Supranuclear Palsy in two, and Frontotemporal Lobar Degeneration-Ubiquitin/TAR DNA-binding protein 43 proteinopathy in one. MRI measures were not significantly different between the patient groups. Reduced perfusion in the left occipital region and worse episodic memory performance may help to distinguish between DLB cases who have never manifested with visual hallucinations and CBS at earlier stages of the disease. Development of reliable neuropsychological and imaging markers that improve diagnostic accuracy will become increasingly important as disease modifying therapies become available.

A study of the local pressure field in turbulent shear flow and its relation to aerodynamic noise generation

NASA Technical Reports Server (NTRS)

Jones, B. G.; Planchon, H. P., Jr.

1973-01-01

Work during the period of this report has been in three areas: (1) pressure transducer error analysis, (2) fluctuating velocity and pressure measurements in the NASA Lewis 6-inch diameter quiet jet facility, and (3) measurement analysis. A theory was developed and experimentally verified to quantify the pressure transducer velocity interference error. The theory and supporting experimental evidence show that the errors are a function of the velocity field's turbulent structure. It is shown that near the mixing layer center the errors are negligible. Turbulent velocity and pressure measurements were made in the NASA Lewis quiet jet facility. Some preliminary results are included.

Investigating the Lewis acidity of aluminium fluoride surfaces

NASA Astrophysics Data System (ADS)

Bailey, C. L.; Mukhopadhyay, S.; Wander, A.; Harrison, N. M.

2008-03-01

The current study employs state of the art hybrid-exchange density functional theory (DFT) to investigate the Lewis acidic sites on the β-AlF3 (100) surface. It is shown that the strong Lewis base, NH3, binds to the surface with a binding energy of up to 1.9 eV. This demonstrates that the material is strongly Lewis acidic. We also consider the binding of the weak Lewis base CO to the surface. We calculate the shift in its stretch frequency compared to the gas phase molecule. Shifts are compared to experimental data and are shown to be typical of strong Lewis acidity.

Relating Functional Groups to the Periodic Table

ERIC Educational Resources Information Center

Struyf, Jef

2009-01-01

An introduction to organic chemistry functional groups and their ionic variants is presented. Functional groups are ordered by the position of their specific (hetero) atom in the periodic table. Lewis structures are compared with their corresponding condensed formulas. (Contains 5 tables.)

The Concept of Oxidation States in Metal Complexes

ERIC Educational Resources Information Center

Steinborn, Dirk

2004-01-01

The concepts of oxidation numbers when applied means electrons that are shared between atoms in molecules are assigned to a specific atom. Oxidation numbers are assigned from the Lewis structure of a molecule, with knowledge of the electronegativities of elements.

Students' Knowledge about the Internal Structure of Mice and Cockroaches in Their Environment

ERIC Educational Resources Information Center

Kilic, Selda

2013-01-01

The aim of this study is to determine 9th class students knowledge about the internal structures of mice and cockroaches using drawings. Drawings of 122 students from the 9th class of a high school in the center of Konya about the internal structures of mice and cockroaches have been analyzed. Drawings were analyzed independently by two…

Lewis Acid Assisted Nitrate Reduction with Biomimetic Molybdenum Oxotransferase Complex.

PubMed

Elrod, Lee Taylor; Kim, Eunsuk

2018-03-05

The reduction of nitrate (NO 3 - ) to nitrite (NO 2 - ) is of significant biological and environmental importance. While Mo IV (O) and Mo VI (O) 2 complexes that mimic the active site structure of nitrate reducing enzymes are prevalent, few of these model complexes can reduce nitrate to nitrite through oxygen atom transfer (OAT) chemistry. We present a novel strategy to induce nitrate reduction chemistry of a previously known catalyst Mo IV (O)(SN) 2 (2), where SN = bis(4- tert-butylphenyl)-2-pyridylmethanethiolate, that is otherwise incapable of achieving OAT with nitrate. Addition of nitrate with the Lewis acid Sc(OTf) 3 (OTf = trifluoromethanesulfonate) to 2 results in an immediate and clean conversion of 2 to Mo VI (O) 2 (SN) 2 (1). The Lewis acid additive further reacts with the OAT product, nitrite, to form N 2 O and O 2 . This work highlights the ability of Sc 3+ additives to expand the reactivity scope of an existing Mo IV (O) complex together with which Sc 3+ can convert nitrate to stable gaseous molecules.

Bifurcation and extinction limit of stretched premixed flames with chain-branching intermediate kinetics and radiative loss

NASA Astrophysics Data System (ADS)

Zhang, Huangwei; Chen, Zheng

2018-05-01

Premixed counterflow flames with thermally sensitive intermediate kinetics and radiation heat loss are analysed within the framework of large activation energy. Unlike previous studies considering one-step global reaction, two-step chemistry consisting of a chain branching reaction and a recombination reaction is considered here. The correlation between the flame front location and stretch rate is derived. Based on this correlation, the extinction limit and bifurcation characteristics of the strained premixed flame are studied, and the effects of fuel and radical Lewis numbers as well as radiation heat loss are examined. Different flame regimes and their extinction characteristics can be predicted by the present theory. It is found that fuel Lewis number affects the flame bifurcation qualitatively and quantitatively, whereas radical Lewis number only has a quantitative influence. Stretch rates at the stretch and radiation extinction limits respectively decrease and increase with fuel Lewis number before the flammability limit is reached, while the radical Lewis number shows the opposite tendency. In addition, the relation between the standard flammability limit and the limit derived from the strained near stagnation flame is affected by the fuel Lewis number, but not by the radical Lewis number. Meanwhile, the flammability limit increases with decreased fuel Lewis number, but with increased radical Lewis number. Radical behaviours at flame front corresponding to flame bifurcation and extinction are also analysed in this work. It is shown that radical concentration at the flame front, under extinction stretch rate condition, increases with radical Lewis number but decreases with fuel Lewis number. It decreases with increased radiation loss.

Electromagnetic properties of ice coated surfaces

NASA Technical Reports Server (NTRS)

Dominek, A.; Walton, E.; Wang, N.; Beard, L.

1989-01-01

The electromagnetic scattering from ice coated structures is examined. The influence of ice is shown from a measurement standpoint and related to a simple analytical model. A hardware system for the realistic measurement of ice coated structures is also being developed to use in an existing NASA Lewis icing tunnel. Presently, initial measurements have been performed with a simulated tunnel to aid in the development.

Microgravity

NASA Image and Video Library

2004-04-15

Structure Of Flame Balls At Low Lewis-numbers (SOFBALL) Experiment Mounting Structure (EMS) was used to conduct the SOFBALL experiment on Combustion Module-1. The EMS was inserted into the CM-1 combustion chamber. The chamber was filled with a lean fuel/oxidizer mixture and a spark igniter on the EMS ignited the gas. Very small, weak flames, in the shape of spheres, were formed and studied.

Lewis's Woodpecker (Melanerpes lewis): A technical conservation assessment

Treesearch

Stephen C. Abele; Victoria A. Saab; Edward O. Garton

2004-01-01

Lewis's woodpecker (Melanerpes lewis) is a locally common but patchily distributed woodpecker species usually seen in open forests of western North America. The combination of its sporadic distribution, its diet of adult-stage free-living insects (primarily aerial), its preference to nest in burned landscapes, and its variable migratory behavior...

Great (Flame) Balls of Fire! Structure of Flame Balls at Low Lewis-number-2 (SOFBALL-2)

NASA Technical Reports Server (NTRS)

Ronney, Paul; Weiland, Karen J.; Over, Ann (Technical Monitor)

2002-01-01

Everyone knows that an automobile engine wastes fuel and energy when it runs with a fuel-rich mixture. 'Lean' burning, mixing in more air and less fuel, is better for the environment. But lean mixtures also lead to engine misfiring and rough operation. No one knows the ultimate limits for lean operation, for 'weak' combustion that is friendly to the environment while still moving us around. This is where the accidental verification of a decades-old prediction may have strong implications for designing and running low-emissions engines in the 21st century. In 1944, Soviet physicist Yakov Zeldovich predicted that stationary, spherical flames are possible under limited conditions in lean fuel-air mixtures. Dr. Paul Ronney of the University of Southern California accidentally discovered such 'flame balls' in experiments with lean hydrogen-air mixtures in 1984 during drop-tower experiments that provided just 2.2 seconds of near weightlessness. Experiments aboard NASA's low-g aircraft confirmed the results, but a thorough investigation was hampered by the aircraft's bumpy ride. And stable flame balls can only exist in microgravity. The potential for investigating combustion at the limits of flammability, and the implications for spacecraft fire safety, led to the Structure of Flame Balls at Low Lewis-number (SOFBALL) experiment flown twice aboard the Space Shuttle on the Microgravity Sciences Laboratory-1 (MSL-1) in 1997. Success there led to the planned reflight on STS-107. Flame balls are the weakest fires yet produced in space or on Earth. Typically each flame ball produced only 1 watt of thermal power. By comparison, a birthday candle produces 50 watts. The Lewis-number measures the rate of diffusion of fuel into the flame ball relative to the rate of diffusion of heat away from the flame ball. Lewis-number mixtures conduct heat poorly. Hydrogen and methane are the only fuels that provide low enough Lewis-numbers to produce stable flame balls, and even then only for very weak, barely flammable mixtures. Nevertheless, under these conditions flame balls give scientists the opportunity to test models in one of the simplest combustion experiments possible. SOFBALL-2 science objectives include: Improving our understanding of the flame ball phenomenon; Determining the conditions under which flame balls exist; Testing predictions of flame ball lifetimes; Acquiring more precise data for critical model comparison.

Structural identification of Zn xZr yO z catalysts for Cascade aldolization and self-deoxygenation reactions

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

Baylon, Rebecca A. L.; Sun, Junming; Kovarik, Libor

Complementary characterizations, such as nitrogen sorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), visible Raman, scanning transmission electron microscopy (STEM) coupled with elemental mapping, NH3/CO2 temperature programmed desorption (NH3/CO2-TPD), infrared spectroscopic analysis of adsorbed pyridine (Py-IR), and CO2-IR, have been employed to identify the structure and surface chemistry (i.e., acid-base) of mixed Zn xZr yO z oxide catalysts of varied ratios of Zn/Zr. Atomically dispersed Zn2+ species are present in the framework within a thin surface shell (1.5-2.0 nm) of ZrO2 particles when the Zn/Zr ratio is smaller than 1/10; when the ratio is above this, both atomically dispersed Zn2+more » and ZnO clusters coexist in mixed Zn xZr yO z oxide catalysts. The presence of ZnO clusters shows no significant side effect but only a slight increase of selectivity to CO2, caused by steam reforming. The incorporation of atomic Zn2+ into the ZrO2 framework was found to not only passivate strong Lewis acid sites (i.e., Zr-O-Zr) on ZrO2, but to also generate new Lewis acid-base site pairs with enhanced Lewis basicity on the bridged O (i.e., ). In the mixed ketone (i.e., acetone and methyl ethyl ketone (MEK)) reactions, while the passivation of strong acid sites can be correlated to the inhibition of side reactions, such as ketone decomposition and coking, the new Lewis acid-base pairs introduced enhance the cascade aldolization and self-deoxygenation reactions involved in olefin (C3=-C6=) production. More importantly, the surface acid-base properties change with varying Zn/Zr ratios, which in turn affect the cross- and self-condensation reactivity and subsequent distribution of olefins.« less

Structural Identification of Zn xZr yO z Catalysts for Cascade Aldolization and Self-Deoxygenation Reactions

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

Baylon, Rebecca A. L.; Sun, Junming; Kovarik, Libor

Here, complementary characterizations, such as nitrogen sorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), visible Raman, scanning transmission electron microscopy (STEM) coupled with elemental mapping, NH 3/CO 2 temperature programmed desorption (NH 3/CO 2-TPD), infrared spectroscopic analysis of adsorbed pyridine (Py-IR), and CO 2-IR, have been employed to identify the structure and surface chemistry (i.e., acid-base) of mixed Zn xZr yO z oxide catalysts of varied ratios of Zn/Zr. Atomically dispersed Zn 2+ species are present in the framework within a thin surface shell (1.5-2.0 nm) of ZrO 2 particles when the Zn/Zr ratio is smaller than 1/10; when the ratio is above this, both atomically dispersed Zn 2+ and ZnO clusters coexist in mixed Zn xZr yO z oxide catalysts. The presence of ZnO clusters shows no significant side effect but only a slight increase of selectivity to CO 2, caused by steam reforming. The incorporation of atomic Zn 2+ into the ZrO 2 framework was found to not only passivate strong Lewis acid sites (i.e., Zr-O-Zr) on ZrO 2, but to also generate new Lewis acid-base site pairs with enhanced Lewis basicity on the bridged O (i.e., Zr—omore » $$\\curvearrowleft\\atop{e\\atop—}$$Zn). In the mixed ketone (i.e., acetone and methyl ethyl ketone (MEK)) reactions, while the passivation of strong acid sites can be correlated to the inhibition of side reactions, such as ketone decomposition and coking, the new Lewis acid-base pairs introduced enhance the cascade aldolization and self-deoxygenation reactions involved in olefin (C 3 =-C 6 =) production. More importantly, the surface acid-base properties change with varying Zn/Zr ratios, which in turn affect the cross- and self-condensation reactivity and subsequent distribution of olefins.« less

The μ3 model of acids and bases: extending the Lewis theory to intermetallics.

PubMed

Stacey, Timothy E; Fredrickson, Daniel C

2012-04-02

A central challenge in the design of new metallic materials is the elucidation of the chemical factors underlying the structures of intermetallic compounds. Analogies to molecular bonding phenomena, such as the Zintl concept, have proven very productive in approaching this goal. In this Article, we extend a foundational concept of molecular chemistry to intermetallics: the Lewis theory of acids and bases. The connection is developed through the method of moments, as applied to DFT-calibrated Hückel calculations. We begin by illustrating that the third and fourth moments (μ(3) and μ(4)) of the electronic density of states (DOS) distribution tune the properties of a pseudogap. μ(3) controls the balance of states above and below the DOS minimum, with μ(4) then determining the minimum's depth. In this way, μ(3) predicts an ideal occupancy for the DOS distribution. The μ(3)-ideal electron count is used to forge a link between the reactivity of transition metals toward intermetallic phase formation, and that of Lewis acids and bases toward adduct formation. This is accomplished through a moments-based definition of acidity which classifies systems that are electron-poor relative to the μ(3)-ideal as μ(3)-acidic, and those that are electron-rich as μ(3)-basic. The reaction of μ(3) acids and bases, whether in the formation of a Lewis acid/base adduct or an intermetallic phase, tends to neutralize the μ(3) acidity or basicity of the reactants. This μ(3)-neutralization is traced to the influence of electronegativity differences at heteroatomic contacts on the projected DOS curves of the atoms involved. The role of μ(3)-acid/base interactions in intermetallic phases is demonstrated through the examination of 23 binary phases forming between 3d metals, the stability range of the CsCl type, and structural trends within the Ti-Ni system.

E-selectin: sialyl Lewis, a dependent adhesion of colon cancer cells, is inhibited differently by antibodies against E-selectin ligands.

PubMed

Srinivas, U; Påhlsson, P; Lundblad, A

1996-09-01

Recent studies have demonstrated that selectins, a new family of cell-adhesion molecules with similar domain structures, mediate the adhesion of peripheral blood cells to interleukin-1 (IL-1)-activated endothelium. In the present study the authors evaluated the role of E-selectin-Sialyl Lewis x (SLe(x))/ Sialyl Lewis a (SLe(a)) interaction in mediating in vitro adhesion of two colon cancer cell lines, HT-29 and COLO 201, to human umbilical cord endothelial cells (HUVEC). Colon cancer cell lines had a strong expression of blood group-related carbohydrate epitopes as evaluated by fluorescence-activated cell sorter (FACS) analysis. It was established that adhesion of HT-29 and COLO 201 cells to IL-1 stimulated HUVEC was calcium dependent and could be inhibited by a monoclonal antibody directed against E-selectin. Prior incubation of cells with two different antibodies directed against SLe(x) and antibodies directed against related Lewis epitopes, Le(x) and Le(a), had no significant effect on adhesion. Three antibodies directed against SLe(a) differed in their capacity to inhibit the adhesion of HT-29 and COLO 201 cells to HUVEC. Only one antibody directed against the SLe(a) structure was effective in inhibiting adhesion of both COLO 201 and HT-29 cells. The difference could not be attributed to titre, the type or number of glycoproteins, or to a difference in the amount of SLe(a) present on individual proteins, suggesting that presence and right presentation of SLe(a) epitope might be important for adhesion of colon cancer cells. Finally, in the in vitro system used, adhesion of HT-29 and COLO 201 cells to activated HUVEC is mediated predominantly by E-selectin/SLe(a) interaction. SLe(x) and related epitopes, Le(x) and Le(a), seem to have limited relevance for colon cancer cell recognition of E-selectin.

Structural Identification of Zn xZr yO z Catalysts for Cascade Aldolization and Self-Deoxygenation Reactions

DOE PAGES

Baylon, Rebecca A. L.; Sun, Junming; Kovarik, Libor; ...

2018-04-22

Here, complementary characterizations, such as nitrogen sorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), visible Raman, scanning transmission electron microscopy (STEM) coupled with elemental mapping, NH 3/CO 2 temperature programmed desorption (NH 3/CO 2-TPD), infrared spectroscopic analysis of adsorbed pyridine (Py-IR), and CO 2-IR, have been employed to identify the structure and surface chemistry (i.e., acid-base) of mixed Zn xZr yO z oxide catalysts of varied ratios of Zn/Zr. Atomically dispersed Zn 2+ species are present in the framework within a thin surface shell (1.5-2.0 nm) of ZrO 2 particles when the Zn/Zr ratio is smaller than 1/10; when the ratio is above this, both atomically dispersed Zn 2+ and ZnO clusters coexist in mixed Zn xZr yO z oxide catalysts. The presence of ZnO clusters shows no significant side effect but only a slight increase of selectivity to CO 2, caused by steam reforming. The incorporation of atomic Zn 2+ into the ZrO 2 framework was found to not only passivate strong Lewis acid sites (i.e., Zr-O-Zr) on ZrO 2, but to also generate new Lewis acid-base site pairs with enhanced Lewis basicity on the bridged O (i.e., Zr—omore » $$\\curvearrowleft\\atop{e\\atop—}$$Zn). In the mixed ketone (i.e., acetone and methyl ethyl ketone (MEK)) reactions, while the passivation of strong acid sites can be correlated to the inhibition of side reactions, such as ketone decomposition and coking, the new Lewis acid-base pairs introduced enhance the cascade aldolization and self-deoxygenation reactions involved in olefin (C 3 =-C 6 =) production. More importantly, the surface acid-base properties change with varying Zn/Zr ratios, which in turn affect the cross- and self-condensation reactivity and subsequent distribution of olefins.« less

Interim Stabilization Equipment Essential and Support Drawing Plan

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

KOCH, M.R.

The purpose of this document is to list the Interim Stabilization equipment drawings that are classified as Essential or Support drawings. Essential Drawings: Those drawings identified by the facility staff as necessary to directly support the safe operation of the facility or equipment. Support Drawings: Those drawings identified by the facility staff that further describe the design details of structures, systems or components shown on essential drawings.

1. Photographic copy of engineering drawing showing structure of Test ...

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

1. Photographic copy of engineering drawing showing structure of Test Stand 'B' (4215/E-16), also known as the 'Short Snorter.' California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering 'Structural Addition - Bldg. E-12, Edwards Test Station,' drawing no. E12/1-1, 8 August 1957. - Jet Propulsion Laboratory Edwards Facility, Test Stand B, Edwards Air Force Base, Boron, Kern County, CA

An Overview of Lewis Basicity and Affinity Scales

ERIC Educational Resources Information Center

Laurence, Christian; Graton, Jerome; Gal, Jean-Francois

2011-01-01

The impossibility of establishing a universal scale of Lewis basicity does not prevent the determination of the quantitative behavior of Lewis bases, thanks to scales constructed against particular Lewis acids: BF[subscript 3], 4-FC[subscript 6]H[subscript 4]OH, I[subscript 2], Li[superscript +], Na[superscript +], K[superscript +], Al[superscript…

Visual hallucinations in dementia with Lewy bodies: transcranial magnetic stimulation study

PubMed Central

Taylor, John-Paul; Firbank, Michael; Barnett, Nicola; Pearce, Sarah; Livingstone, Anthea; Mosimann, Urs; Eyre, Janet; McKeith, Ian G.; O’Brien, John T.

2011-01-01

Background The aetiology of visual hallucinations is poorly understood in dementia with Lewy bodies. Pathological alterations in visual cortical excitability may be one contributory mechanism. Aims To determine visual cortical excitability in people with dementia with Lewy bodies compared with aged-matched controls and also the relationship between visual cortical excitability and visual hallucinations in dementia with Lewy bodies. Method Visual cortical excitability was determined by using transcranial magnetic stimulation (TMS) applied to the occiput to elicit phosphenes (transient subjective visual responses) in 21 patients with dementia with Lewy bodies and 19 age-matched controls. Results Phosphene parameters were similar between both groups. However, in the patients with dementia with Lewy bodies, TMS measures of visual cortical excitability correlated strongly with the severity of visual hallucinations (P = 0.005). Six patients with dementia with Lewy bodies experienced visual hallucination-like phosphenes (for example, seeing people or figures on stimulation) compared with none of the controls (P = 0.02). Conclusions Increased visual cortical excitability in dementia with Lewy bodies does not appear to explain visual hallucinations but it may be a marker for their severity. PMID:22016436

Streptococcal cell wall-induced arthritis and adjuvant arthritis in F344----Lewis and in Lewis----F344 bone marrow chimeras

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

van Bruggen, M.C.; van den Broek, M.F.; van den Berg, W.B.

1991-09-01

Streptococcal cell wall (SCW)-induced arthritis and adjuvant arthritis (AA) are rat models for chronic, erosive polyarthritis. Both models can be induced in susceptible Lewis rats, whereas F344 rats are resistant. In AA as well as in SCW arthritis, antigen-specific T lymphocytes have been demonstrated to be crucial for chronic disease. In this communication the authors describe their studies to probe the cellular mechanism responsible for the difference in susceptibility of Lewis and F344, using bone marrow chimeras. By transplanting bone marrow cells from F344 into lethally irradiated Lewis recipients, Lewis rats were rendered resistant to SCW arthritis induction. F344 ratsmore » reconstituted with Lewis bone marrow, i.e., Lewis----F344 chimeras, develop an arthritis upon SCW injection. For AA comparable results were obtained. These data suggest that both resistance and susceptibility to bacterium-induced chronic arthritis are mediated by hemopoietic/immune cells and that the recipiental environment does not influence the susceptibility to chronic joint inflammation.« less

Elucidating the Key Role of a Lewis Base Solvent in the Formation of Perovskite Films Fabricated from the Lewis Adduct Approach.

PubMed

Cao, Xiaobing; Zhi, Lili; Li, Yahui; Fang, Fei; Cui, Xian; Yao, Youwei; Ci, Lijie; Ding, Kongxian; Wei, Jinquan

2017-09-27

High-quality perovskite films can be fabricated from Lewis acid-base adducts through molecule exchange. Substantial work is needed to fully understand the formation mechanism of the perovskite films, which helps to further improve their quality. Here, we study the formation of CH 3 NH 3 PbI 3 perovskite films by introducing some dimethylacetamide into the PbI 2 /N,N-dimethylformamide solution. We reveal that there are three key processes during the formation of perovskite films through the Lewis acid-base adduct approach: molecule intercalation of solvent into the PbI 2 lattice, molecule exchange between the solvent and CH 3 NH 3 I, and dissolution-recrystallization of the perovskite grains during annealing. The Lewis base solvents play multiple functions in the above processes. The properties of the solvent, including Lewis basicity and boiling point, play key roles in forming smooth perovskite films with large grains. We also provide some rules for choosing Lewis base additives to prepare high-quality perovskite films through the Lewis adduct approach.

Nanoconfinement Effects in Catalysis

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

Kung, Harold H.

In this investigation, the unique properties that stem from the constrained environment and enforced proximity of functional groups at the active site were demonstrated for a number of systems. The first system is a nanocage structure with silicon-based, atom-thick shells and molecular-size cavities. The shell imparts the expected size exclusion for access to the interior cavity, and the confined space together with the hydrophobic shell strongly influences the stability of charged groups. One consequence is that the interior amine groups in a siloxane nanocage exhibit a shift in their protonation ability that is equivalent to about 4 pH units. Inmore » another nanocage structure designed to possess a core-shell structure in which the core periphery is decorated with carboxylic acid groups and the shell interior is populated with silanol groups, the restricted motion of the core results in limiting the stoichiometry of reaction between carboxylic acid and a Co 2CO 8 complex, which leads to formation and stabilization of Co(I) ions in the nanocage. The second designed catalytic structure is a supported, isolated, Lewis acid Sn-oxide unit derived from a (POSS)-Sn-(POSS) molecular complex (POSS = incompletely condensed silsesquioxane). The Sn center in the (POSS)-Sn-(POSS) complex is present in a tetrahedral coordination, as confirmed by single crystal x-ray crystallography and Sn NMR, and its Lewis acid character is demonstrated with its binding to amines. The retention of the tetrahedral coordination of Sn after heterogenization and mild oxidative treatment is confirmed by characterization using EXAFS, NMR, UV-vis, and DRIFT, and its Lewis acid character is confirmed by stoichiometric binding with pyridine. This Sn-catalyst is active in hydride transfer reactions as a typical solid Lewis acid. In addition, the Sn centers can also create Brønsted acidity with alcohol by binding the alcohol strongly as alkoxide and transferring the hydroxyl H to the neighboring Sn-O-Si bond. The resulting acidic silanol is active in epoxide ring opening and acetalization reactions. The open structure of the Sn center makes it accessible to larger molecules, including cellobiose which can be converted to 5-(hydroxymethyl)-furfural. The third structure is a support planted with functional group pairing of a known separation distance. Using a precursor molecule that contains a hydrolysable silyl ester bond, and making use of known chemistry to convert silanol groups into amino/pyridyl and phosphinyl groups, silica surfaces with carboxylic acid/silanol, carboxylic acid/amine, carboxylic acid/pyridine, and carboxylic acid/phosphine pairs can be constructed. The amino groups paired with carboxylic acid on such a surface is more active in the Henry reaction of 4-nitobenzaldehyde with nitromethane.« less

Hippocampal α-Synuclein in Dementia with Lewy Bodies Contributes to Memory Impairment and Is Consistent with Spread of Pathology

PubMed Central

Roy, Subhojit; Galasko, Douglas R.; Hansen, Lawrence A.; Masliah, Eliezer

2017-01-01

Despite considerable research to uncover them, the anatomic and neuropathologic correlates of memory impairment in dementia with Lewy bodies (DLB) remain unclear. While some studies have implicated Lewy bodies in the neocortex, others have pointed to α-synuclein pathology in the hippocampus. We systematically examined hippocampal Lewy pathology and its distribution in hippocampal subfields in 95 clinically and neuropathologically characterized human cases of DLB, finding that α-synuclein pathology was highest in two hippocampal-related subregions: the CA2 subfield and the entorhinal cortex (EC). While the EC had numerous classic somatic Lewy bodies, CA2 contained mainly Lewy neurites in presumed axon terminals, suggesting the involvement of the EC → CA2 circuitry in the pathogenesis of DLB symptoms. Clinicopathological correlations with measures of verbal and visual memory supported a role for EC Lewy pathology, but not CA2, in causing these memory deficits. Lewy pathology in CA1—the main output region for CA2—correlated best with results from memory testing despite a milder pathology. This result indicates that CA1 may be more functionally relevant than CA2 in the context of memory impairment in DLB. These correlations remained significant after controlling for several factors, including concurrent Alzheimer's pathology (neuritic plaques and neurofibrillary tangles) and the interval between time of testing and time of death. Our data suggest that although hippocampal Lewy pathology in DLB is predominant in CA2 and EC, memory performance correlates most strongly with CA1 burden. SIGNIFICANCE STATEMENT This study provides a detailed neuropathologic analysis of hippocampal Lewy pathology in human patients with autopsy-confirmed dementia with Lewy bodies. The approach—informed by regional molecular markers, concurrent Alzheimer's pathology analysis, and relevant clinical data—helps tease out the relative contribution of Lewy pathology to memory dysfunction in the disease. Levels of Lewy pathology were found to be highest in the hippocampal CA2 subregion and entorhinal cortex, implicating a potentially overlooked circuit in disease pathogenesis. However, correlation with memory performance was strongest with CA1. This unexpected finding suggests that Lewy pathology must reach a critical burden across hippocampal circuitry to contribute to memory dysfunction beyond that related to other factors, notably coexisting Alzheimer's disease tau pathology. PMID:28039370

Cognitive impairment, decline and fluctuations in older community-dwelling subjects with Lewy bodies

PubMed Central

Arvanitakis, Z.; Yu, L.; Boyle, P. A.; Leurgans, S. E.; Bennett, D. A.

2012-01-01

Lewy bodies are common in the ageing brain and often co-occur with Alzheimer’s disease pathology. There is little known regarding the independent role of Lewy body pathology in cognition impairment, decline and fluctuations in community-dwelling older persons. We examined the contribution of Lewy body pathology to dementia, global cognition, cognitive domains, cognitive decline and fluctuations in 872 autopsied subjects (mean age = 87.9 years) from the Rush Religious Order Study (n = 491) and Memory and Aging Project (n = 381) longitudinal community-based clinical–pathological studies. Dementia was based on a clinical evaluation; annual cognitive performance tests were used to create a measure of global cognition and five cognitive domains. Lewy body type was determined by using α-synuclein immunostained sections of substantia nigra, limbic and neocortical regions. Statistical models included multiple regression models for dementia and cognition and mixed effects models for decline. Cognitive fluctuations were estimated by comparing standard deviations of individual residuals from mean trajectories of decline in those with and without Lewy bodies. All models controlled for age, sex, education, Alzheimer’s disease pathology and infarcts. One hundred and fifty-seven subjects (18%) exhibited Lewy body pathology (76 neocortical-type, 54 limbic-type and 27 nigra-predominant). One hundred and three (66%) subjects with Lewy body pathology had a pathologic diagnosis of Alzheimer’s disease. Neocortical-type, but not nigral-predominant or limbic-type Lewy body pathology was related to an increased odds of dementia (odds ratio = 3.21; 95% confidence interval = 1.78–5.81) and lower cognition (P < 0.001) including episodic memory function (P < 0.001) proximate to death. Neocortical-type Lewy body pathology was also related to a faster decline in global cognition (P < 0.001), decline in all five specific cognitive domains (all P-values < 0.001), and to fluctuations in decline of working and semantic memory (P-values < 0.001). Limbic-type Lewy body pathology was related to lower and faster decline in visuospatial skills (P = 0.042). The relationship of Lewy body pathology to cognition and dementia was not modified by Alzheimer’s disease pathology. Neocortical-type Lewy body pathology is associated with increased odds of dementia; lower and more rapid decline in all cognitive domains including episodic memory and fluctuations in decline in semantic and working memory. Limbic-type Lewy body pathology is specifically associated with lower and more rapid decline in visuospatial skills. The effect of Lewy body pathology on cognition appears to be independent of Alzheimer’s disease pathology. PMID:23065790

Design of stereoelectronically promoted super lewis acids and unprecedented chemistry of their complexes.

PubMed

Foroutan-Nejad, Cina; Vicha, Jan; Marek, Radek

2014-09-01

A new family of stereoelectronically promoted aluminum and scandium super Lewis acids is introduced on the basis of state-of-the-art computations. Structures of these molecules are designed to minimize resonance electron donation to central metal atoms in the Lewis acids. Acidity of these species is evaluated on the basis of their fluoride-ion affinities relative to the antimony pentafluoride reference system. It is demonstrated that introduced changes in the stereochemistry of the designed ligands increase acidity considerably relative to Al and Sc complexes with analogous monodentate ligands. The high stability of fluoride complexes of these species makes them ideal candidates to be used as weakly coordinating anions in combination with highly reactive cations instead of conventional Lewis acid-fluoride complexes. Further, the interaction of all designed molecules with methane is investigated. All studied acids form stable pentavalent-carbon complexes with methane. In addition, interactions of the strongest acid of this family with very weak bases, namely, H2, N2, carbon oxides, and noble gases were investigated; it is demonstrated that this compound can form considerably stable complexes with the aforementioned molecules. To the best of our knowledge, carbonyl and nitrogen complexes of this species are the first hypothetical four-coordinated carbonyl and nitrogen complexes of aluminum. The nature of bonding in these systems is studied in detail by various bonding analysis approaches. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lewis's Woodpecker: Melanerpes lewis

Treesearch

Bret W. Tobalske; Kerri T. Vierling; Victoria A. Saab

2013-01-01

During the historic Lewis and Clark expedition, Meriwether Lewis wrote on 20 July 1805, "I saw a black woodpecker (or crow) today it is a distinct species of woodpecker; it has a long tail and flys a good deal like the jay bird" (sic, Thwaites 1905). Subsequent observations of flight and vocalization reminded him of the Red-headed Woodpecker (Melanerpes...

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

Heller, Forrest D.; Casella, Amanda J.; Lumetta, Gregg J.

A Lewis cell was designed and constructed for investigating solvent extraction systems by spectrophotometrically monitoring both the organic and aqueous phases in real time. This new Lewis cell was tested and shown to perform well compared to other previously reported Lewis cell designs. The advantage of the new design is that the spectroscopic measurement allows determination of not only metal ion concentrations, but also information regarding chemical speciation—information not available with previous Lewis cell designs. For convenience, the new Lewis cell design was dubbed COSMOFLEX (COntinuous Spectroscopic MOnitoring of Forrest’s Liquid-liquid EXtraction cell).

The Lewis heat pipe code with application to SP-100 GES heat pipes

NASA Astrophysics Data System (ADS)

Baker, Karl W.; Tower, Leonard K.

The NASA Lewis Research Center has a thermal management program supporting SP-100 goals, which includes heat pipe radiator development. As a part of the program Lewis has elected to prepare an in-house heat pipe code tailored to the needs of its SP-100 staff to supplement codes from other sources. The latter, designed to meet the needs of the originating organizations, were deemed not entirely appropriate for use at Lewis. However, a review of their features proved most beneficial in the design of the Lewis code.

The development of hydrogen sensor technology at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Neudeck, Philip G.; Jefferson, G. D.; Madzsar, G. C.; Liu, C. C.; Wu, Q. H.

1993-01-01

The detection of hydrogen leaks in aerospace applications, especially those involving hydrogen fuel propulsion systems, is of extreme importance for reasons of reliability, safety, and economy. Motivated by leaks occurring in liquid hydrogen lines supplying the main engine of the Space Shuttle, NASA Lewis has initiated a program to develop point-contact hydrogen sensors which address the needs of aerospace applications. Several different approaches are being explored. They include the fabrication of PdAg Schottky diode structures, the characterization of PdCr as a hydrogen sensitive alloy, and the use of SiC as a semiconductor for hydrogen sensors. This paper discusses the motivation behind and present status of each of the major components of the NASA LeRC hydrogen sensor program.

Modeling Code Is Helping Cleveland Develop New Products

NASA Technical Reports Server (NTRS)

1998-01-01

Master Builders, Inc., is a 350-person company in Cleveland, Ohio, that develops and markets specialty chemicals for the construction industry. Developing new products involves creating many potential samples and running numerous tests to characterize the samples' performance. Company engineers enlisted NASA's help to replace cumbersome physical testing with computer modeling of the samples' behavior. Since the NASA Lewis Research Center's Structures Division develops mathematical models and associated computation tools to analyze the deformation and failure of composite materials, its researchers began a two-phase effort to modify Lewis' Integrated Composite Analyzer (ICAN) software for Master Builders' use. Phase I has been completed, and Master Builders is pleased with the results. The company is now working to begin implementation of Phase II.

Large scale cryogenic fluid systems testing

NASA Technical Reports Server (NTRS)

1992-01-01

NASA Lewis Research Center's Cryogenic Fluid Systems Branch (CFSB) within the Space Propulsion Technology Division (SPTD) has the ultimate goal of enabling the long term storage and in-space fueling/resupply operations for spacecraft and reusable vehicles in support of space exploration. Using analytical modeling, ground based testing, and on-orbit experimentation, the CFSB is studying three primary categories of fluid technology: storage, supply, and transfer. The CFSB is also investigating fluid handling, advanced instrumentation, and tank structures and materials. Ground based testing of large-scale systems is done using liquid hydrogen as a test fluid at the Cryogenic Propellant Tank Facility (K-site) at Lewis' Plum Brook Station in Sandusky, Ohio. A general overview of tests involving liquid transfer, thermal control, pressure control, and pressurization is given.

Research and technology, Lewis Research Center

NASA Technical Reports Server (NTRS)

1982-01-01

Aeronautics, space, and terrestrial energy research is covered. Energy conversion processes and systems for propulsion in the atmosphere, in space, and on the ground are reviewed. Electric energy generation and storage for both terrestrial and space applications and materials and structures for such systems are also reviewed.

Spectroscopic and first principles investigation on 4-[(4-pyridinylmethylene)amino]-benzoic acid bearing pyridyl and carboxyl anchoring groups

NASA Astrophysics Data System (ADS)

Zhang, Lei; Wang, Qiaoyi

2018-03-01

We report a combined experimental and computational investigation on the structure and photophysics of 4-[(4-pyridinylmethylene)amino]-benzoic acid, a functional molecule bearing two anchoring groups for attachment onto a TiO2 surface and perovskite surface, for potential solar cell application. This molecule possesses interesting adsorption properties in perovskite solar cell because the pyridyl group serves as the Lewis base and targets Lewis acidic sites in the perovskite surface, while the carboxyl group targets TiO2 surface, improving the coupling between the perovskite surface and the TiO2 surface. The electronic structures of the molecule and its photochemistry are revealed by the UV-vis absorption spectra and the fluorescence spectra under visible light irradiation, which are combined with density functional theory (DFT) and time-dependent density functional theory (TDDFT) analysis. Considering the bi-anchoring groups and the conjugated π system embedded in the molecule, we anticipate it can molecular engineer the TiO2/perovskite interface in perovskite solar cell.

Engaging Organic Chemistry Students Using ChemDraw for iPad

ERIC Educational Resources Information Center

Morsch, Layne A.; Lewis, Michael

2015-01-01

Drawing structures, mechanisms, and syntheses is a vital part of success in organic chemistry courses. ChemDraw for iPad has been used to increase classroom experiences in the preparation of high quality chemical drawings. The embedded Flick-to-Share allows for simple, real-time exchange of ChemDraw documents. ChemDraw for iPad also allows…

This photocopy of an engineering drawing shows the floor plan ...

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

This photocopy of an engineering drawing shows the floor plan of the Liner Lab, including room functions. Austin, Field & Fry, Architects Engineers, 22311 West Third Street, Los Angeles 57, California: Edwards Test Station Complex Phase II, Jet Propulsion Laboratory, California Institute of Technology, Edwards Air Force Base, Edwards, California: "Liner Laboratory, Floor Plan and Schedules," drawing no. E33/4-2, 26 June 1962. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering: engineering drawings of structures at JPL Edwards Facility. Drawings on file at JPL Plant Engineering, Pasadena, California. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering: engineering drawings of structures at JPL Edwards Facility. Drawings on file at JPL Plant Engineering, Pasadena, California - Jet Propulsion Laboratory Edwards Facility, Liner Laboratory, Edwards Air Force Base, Boron, Kern County, CA

Small Molecule Activation by Intermolecular Zr(IV)-Phosphine Frustrated Lewis Pairs.

PubMed

Metters, Owen J; Forrest, Sebastian J K; Sparkes, Hazel A; Manners, Ian; Wass, Duncan F

2016-02-17

We report intermolecular transition metal frustrated Lewis pairs (FLPs) based on zirconocene aryloxide and phosphine moieties that exhibit a broad range of small molecule activation chemistry that has previously been the preserve of only intramolecular pairs. Reactions with D2, CO2, THF, and PhCCH are reported. By contrast with previous intramolecular examples, these systems allow facile access to a variety of steric and electronic characteristics at the Lewis acidic and Lewis basic components, with the three-step syntheses of 10 new intermolecular transition metal FLPs being reported. Systematic variation to the phosphine Lewis base is used to unravel steric considerations, with the surprising conclusion that phosphines with relatively small Tolman steric parameters not only give highly reactive FLPs but are often seen to have the highest selectivity for the desired product. DOSY NMR spectroscopic studies on these systems reveal for the first time the nature of the Lewis acid/Lewis base interactions in transition metal FLPs of this type.

Lewis Acidic Ionic Liquids.

PubMed

Brown, Lucy C; Hogg, James M; Swadźba-Kwaśny, Małgorzata

2017-08-21

Until very recently, the term Lewis acidic ionic liquids (ILs) was nearly synonymous with halometallate ILs, with a strong focus on chloroaluminate(III) systems. The first part of this review covers the historical context in which these were developed, speciation of a range of halometallate ionic liquids, attempts to quantify their Lewis acidity, and selected recent applications: in industrial alkylation processes, in supported systems (SILPs/SCILLs) and in inorganic synthesis. In the last decade, interesting alternatives to halometallate ILs have emerged, which can be divided into two sub-sections: (1) liquid coordination complexes (LCCs), still based on halometallate species, but less expensive and more diverse than halometallate ionic liquids, and (2) ILs with main-group Lewis acidic cations. The two following sections cover these new liquid Lewis acids, also highlighting speciation studies, Lewis acidity measurements, and applications.

Photocopy of drawing (original drawing of War Department Theater in ...

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

Photocopy of drawing (original drawing of War Department Theater in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1940 architectural drawings by Construction Division, Office of the Quartermaster General)STRUCTURAL - FOUNDATIONS - MacDill Air Force Base, Base Theater, 2420 Florida Keys Avenue, Tampa, Hillsborough County, FL

Drug Abuse & the Criminal Justice System. Chapter 7.

ERIC Educational Resources Information Center

Acampora, Alfonso P., Ed.; Nebelkopf, Ethan, Ed.

This document contains seven papers from the ninth World Conference of Therapeutic Communities (TCs) that deal with drug abuse and the criminal justice system. Papers include: (1) "Some Characteristics of the Social Structure & Social Organization of the TCs" (Lewis Yablonsky); (2) "Therapeutics & Incarceration: They Said It…

Investigating Students' Similarity Judgments in Organic Chemistry

ERIC Educational Resources Information Center

Graulich, N.; Bhattacharyya, G.

2017-01-01

Organic chemistry is possibly the most visual science of all chemistry disciplines. The process of scientific inquiry in organic chemistry relies on external representations, such as Lewis structures, mechanisms, and electron arrows. Information about chemical properties or driving forces of mechanistic steps is not available through direct…

Ransom, Religion, and Red Giants: C.S. Lewis and Fred Hoyle

NASA Astrophysics Data System (ADS)

Larsen, Kristine

2010-01-01

Famed fantasy writer C.S. Lewis (1898-1963) was known to friends as a well-read astronomy aficionado. However, this medieval scholar and Christian apologist embraced a pre-Copernican universe (with its astrological overtones) in his Chronicles of Narnia series and defended the beauty and relevance of the geocentric model in his final academic work, "The Discarded Image". In the "Ransom Trilogy” ("Out of the Silent Planet", "Perelandra", and "That Hideous Strength") philologist Ransom (loosely based on Lewis's close friend J.R.R. Tolkien) travels to Lewis's visions of Mars and Venus, where he interacts with intelligent extraterrestrials, battles with evil scientists, and aids in the continuation of extraterrestrial Christian values. In the final book, Ransom is joined by a handful of colleagues in open warfare against the satanic N.I.C.E. (National Institute for Coordinated Experiments). Geneticist and evolutionary biologist J.B.S. Haldane criticized Lewis for his scientifically inaccurate descriptions of the planets, and his disdain for the scientific establishment. Lewis responded to the criticism in essays of his own. Another of Lewis's favorite scientific targets was atheist Fred Hoyle, whom he openly criticized for anti-Christian statements in Hoyle's BBC radio series. Writer and Lewis friend Dorothy L. Sayers voiced her own criticism of Hoyle. In a letter, Lewis dismissed Hoyle as "not a great philosopher (and none of my scientific colleagues think much of him as a scientist.” Given Lewis's lack of respect for Hoyle, and use of creative license in describing the planets, and the flat-earth, "geocentric” Narnia, it is surprising that Lewis very carefully includes an astronomically correct description of red giants in two novels in the Narnia series ("The Magician's Nephew" and "The Last Battle"). This inclusion is even more curious given that Fred Hoyle is well-known as one of the pioneers in the field of stellar death and the properties of red giants.

Photocopy of drawing. ALTITUDE CHAMBERS “L” & “R” STRUCTURES. NASA, ...

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

Photocopy of drawing. ALTITUDE CHAMBERS “L” & “R” STRUCTURES. NASA, John F. Kennedy Space Center, Florida. Drawing 68-K-L-11213, NASA KSC, November, 1968. CHAMBER “R” ELEVATION. Sheet 4 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

Photocopy of drawing. ALTITUDE CHAMBERS “L” & “R” STRUCTURES. NASA, ...

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

Photocopy of drawing. ALTITUDE CHAMBERS “L” & “R” STRUCTURES. NASA, John F. Kennedy Space Center, Florida. Drawing 68-K-L-11213, NASA KSC, November, 1968. WORK PLATFORM DETAIL. Sheet 6 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

Photocopy of drawing. ALTITUDE CHAMBERS “L” & “R” STRUCTURES. NASA, ...

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

Photocopy of drawing. ALTITUDE CHAMBERS “L” & “R” STRUCTURES. NASA, John F. Kennedy Space Center, Florida. Drawing 68-K-L-11213, NASA KSC, November, 1968. CHAMBER “L” ELEVATION. Sheet 3 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

Structure A, reinforcing details. Drawing No. H2302, as built, Original ...

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

Structure A, reinforcing details. Drawing No. H2-302, as built, Original drawing by Black & Veatch, Consulting Engineers, Kansas City, Missouri, prepared for the U.S. Department of the Army, Office of Engineers, Military Construction Division, Washington, D.C. dated October 1, 1951. - Travis Air Force Base, Building No. 925, W Street, Fairfield, Solano County, CA

10. Photocopy of drawing, February 1958, NUCLEAR REACTOR FACILITY, STRUCTURAL ...

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

10. Photocopy of drawing, February 1958, NUCLEAR REACTOR FACILITY, STRUCTURAL CROSS SECTION. Giffals & Vallet, Inc., L. Rosetti, Associated Architects and Engineers, Detroit, Michigan; and U.S. Army Engineer Division, New England Corps of Engineers, Boston, Massachusetts. Drawing Number 35-84-04. (Original: AMTL Engineering Division, Watertown). - Watertown Arsenal, Building No. 100, Wooley Avenue, Watertown, Middlesex County, MA

Anosmia in dementia is associated with Lewy bodies rather than Alzheimer's pathology

PubMed Central

McShane, R; Nagy, Z; Esiri, M; King, E; Joachim, C; Sullivan, N; Smith, A

2001-01-01

OBJECTIVES—To assess olfactory function of patients with dementia. Odour detection ability is impaired in clinical Parkinson's disease. Evidence of impaired detection in patients with clinically diagnosed Alzheimer's disease is inconsistent. No studies of olfaction have been neuropathologically validated.
METHODS—The olfactory function of 92 patients with dementia and 94 controls was assessed using a simple bedside test as part of the Oxford Project To Investigate Memory and Ageing (OPTIMA). Neuropathological assessment was made of cortical Lewy bodies and substantia nigra (SN) cell counts and of Alzheimer's disease in all 92 patients, 22 of whom had SN Lewy bodies and 43 of whom had only Alzheimer's disease.
RESULTS—Patients with Lewy bodies were more likely to be anosmic than those with Alzheimer's disease or controls. Patients with Alzheimer's disease were not more likely to be anosmic than controls. Nor was anosmia associated with degree of neurofibrillary tangles, as assessed by Braak stage. Among subjects with Lewy bodies, overall cortical Lewy body scores and Lewy body density in the cingulate were higher in those who were anosmic. Consensus clinical criteria for dementia with Lewy bodies had a sensitivity of 64% and specificity of 89%. In the absence of definite Alzheimer's disease, the criteria had sensitivity of 100%. In patients with definite Alzheimer's disease, anosmia was slightly more sensitive (55%) than the consensus criteria (33%). However, the addition of anosmia to the consensus criteria did not improve their overall performance.
CONCLUSION—Dementia with Lewy bodies is associated with impaired odour detection. Misdiagnosis may have accounted for some previous reports of impaired odour detection in Alzheimer's disease. Simple but more sensitive tests of anosmia are required if they are to be clinically useful in identifying patients with dementia with Lewy bodies.

 PMID:11385006

Characterization of the Aluminum-Oxide - Interface in Organic-Based Photoconductors by Electron Tunneling Spectroscopy.

NASA Astrophysics Data System (ADS)

Outzourhit, Abdelkader

In this study both the structure of the native oxide of the aluminum substrate and its electrical properties were investigated using electron tunneling spectroscopy which uses aluminum/aluminum oxide/lead tunnel junctions. It is found that the structure of the oxide as well as the barrier heights vary as a function of the preparation conditions. Room temperature oxidation in air or in the presence of small amounts of water vapor results in a disordered oxide, while glow discharge oxidation in an oxygen plasma leads to a more ordered oxide as evidenced by a sharp Al-O band in the inelastic electron tunneling (IET) spectra of as-grown tunnel junctions. In addition, the thermally oxidized junctions show a large barrier asymmetry (6.1 eV), which decrease as the humidity level is increased. These observations can be correlated with a change in the concentration, charge, and environment of the chemically adsorbed hydroxyl on the surface of the aluminum oxide. Tunneling studies of Hydroxy Squarylium (OHSq)- and PNDMA-doped tunnel junctions reveal the lowering of the effective barrier for electron tunneling as well as the barrier asymmetry in accordance with the modification of the charged hydroxyl groups at the surface of the oxide. IET spectra of these junctions support the Lewis-acid/Lewis-base type of interaction between the oxide surface and the adsorbed molecules. The ionization energy of the OHSq aggregates was measured to be 5.0 eV using the valence band XPS. This parameter was also evaluated from a simple Huckel molecular orbital theory applied to the dye molecule after taking into account the polarization energy. High dark decay rates are associated with low barrier for hole injection into the OHSq aggregates. Schottky emission is the primary cause of the dark decay at low voltages, while the Frenkel -Poole mechanism dominates the dark decay at higher voltages. The Lewis-acid/Lewis-base mechanism for the dark decay is not ruled out. Structural studies reveal the existence of silicon- and sodium-rich protrusions in the samples which show unacceptable dark decay rates. The protrusions can enhance the electric field within the photoconductor and thus lead to higher dark decay rates. (Abstract shortened with permission of author.).

Fort Clatsop : Review of Summer 2005 Operations.

DOT National Transportation Integrated Search

2005-09-30

In anticipation of increased visitation for the Lewis & Clark Bicentennial, Lewis & Clark National Historical Park (LEWI) implemented a remote parking (Netul Landing) and alternative transportation system involving both a shuttle and area transit rou...

Brain Organochlorines and Lewy Pathology: The Honolulu-Asia Aging Study

PubMed Central

Ross, G. Webster; Duda, John E.; Abbott, Robert D.; Pellizzari, Edo; Petrovitch, Helen; Miller, Diane B.; O’Callaghan, James P.; Tanner, Caroline M.; Noorigian, Joseph V.; Masaki, Kamal; Launer, Lenore; White, Lon R.

2012-01-01

Background Although organochlorines have been reported more frequently in Parkinson’s disease (PD) brains than controls, the association with brain Lewy pathology is unknown. Honolulu-Asia Aging Study (HAAS) participants, exposed to organochlorines from a variety of sources during mid-life, represent a population well suited to determine the relationship of brain organochlorines with Lewy pathology in decedents from the longitudinal HAAS. Methods Study design included the measurement of 21 organochlorine levels in frozen occipital lobe samples from HAAS decedents. Alpha-synuclein immunostaining performed on 225 brains was used to identify Lewy bodies and Lewy neurites. Results With the potential for spurious associations to appear between Lewy pathology and 17 organochlorine compounds found to be present in at least one brain, initial assessments identified heptachlor epoxide isomer b, methoxychlor, and benzene hexachloride b as being most important. Prevalence of Lewy pathology was 75% (6/8) among brains with any 2 of the 3 compounds, 48.8% (79/162) among those with 1, and 32.7% (18/55) for those with neither (P=0.007 test for trend). While findings persisted after removing cases with PD and dementia with Lewy bodies, and when adjustments were made for age at death, body mass index, pack-years of cigarette smoking, and coffee intake (p=0.013), results were insignificant when correcting for multiple testing. Conclusions While consistent with earlier accounts of an association between organochlorines and clinical PD, associations with Lewy pathology warrant further study. PMID:22976848

Students' understanding of primary and secondary protein structure: drawing secondary protein structure reveals student understanding better than simple recognition of structures.

PubMed

Harle, Marissa; Towns, Marcy H

2013-01-01

The interdisciplinary nature of biochemistry courses requires students to use both chemistry and biology knowledge to understand biochemical concepts. Research that has focused on external representations in biochemistry has uncovered student difficulties in comprehending and interpreting external representations in addition to a fragmented understanding of fundamental biochemistry concepts. This project focuses on students' understanding of primary and secondary protein structure and drawings (representations) of hydrogen-bonding in alpha helices and beta sheets. Analysis demonstrated that students can recognize and identify primary protein structure concepts when given a polypeptide. However, when asked to draw alpha helices and beta sheets and explain the role of hydrogen bonding their drawings students exhibited a fragmented understanding that lacked coherence. Faculty are encouraged to have students draw molecular level representations to make their mental models more explicit, complete, and coherent. This is in contrast to recognition and identification tasks, which do not adequately probe mental models and molecular level understanding. © 2013 by The International Union of Biochemistry and Molecular Biology.

Understanding early elementary children's conceptual knowledge of plant structure and function through drawings.

PubMed

Anderson, Janice L; Ellis, Jane P; Jones, Alan M

2014-01-01

This study examined children's drawings to explain children's conceptual understanding of plant structure and function. The study explored whether the children's drawings accurately reflect their conceptual understanding about plants in a manner that can be interpreted by others. Drawing, survey, interview, and observational data were collected from 182 students in grades K and 1 in rural southeastern United States. Results demonstrated the children held a wide range of conceptions concerning plant structure and function. These young children held very simple ideas about plants with respect to both their structure and function. Consistent with the drawings, the interviews presented similar findings. © 2014 J. L. Anderson et al. CBE—Life Sciences Education © 2014 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

The Role of MgCl 2 as a Lewis Base in ROMgCl-MgCl 2 Electrolytes for Magnesium-Ion Batteries

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

Pan, Baofei; Huang, Jinhua; He, Meinan

2016-02-04

A series of strong Lewis acid-free alkoxide/siloxide-based Mg electrolytes were deliberately developed with remarkable oxidative stability up to 3.5 V (vs. Mg/Mg2+). Despite the perception of ROMgCl (R=alkyl, silyl) as a strong base, ROMgCl acts like Lewis acid, whereas the role of MgCl2 in was unambiguously demonstrated as a Lewis base through the identification of the key intermediate using single crystal X-ray crystallography. This Lewis-acid-free strategy should provide a prototype system for further investigation of Mg-ion batteries.

Lewy Body Dementia Diagnosis

MedlinePlus

... individuals, it may also be due to the natural course of the disease. All Rights Reserved Lewy Body Dementia Association, Inc. 912 Killian Hill Road S.W., Lilburn, GA 30047 © 2018 Lewy Body Dementia Association, Inc. Connect ...

Research and technology, Lewis Research Center

NASA Technical Reports Server (NTRS)

1985-01-01

The NASA Lewis Research Center's research and technology accomplishments for fiscal year 1985 are summarized. The report is organized into five major sections covering aeronautics, aerospace technology, spaceflight systems, space station systems, and computational technology support. This organization of the report roughly parallels the organization of the Center into directorates. Where appropriate, subheadings are used to identify special topics under the major headings. Results of all research and technology work performed during the fiscal year are contained in Lewis-published technical reports and presentations prepared either by Lewis scientists and engineers or by contractor personnel. In addition, significant results are presented by university faculty or graduate students in technical sessions and in journals of the technical societies. For the reader who desires more information about a particular subject, the Lewis contact will provide that information or references. In 1985, five Lewis products were selected by Research and Development Magazine for IR-100 awards. All are described and identified. In addition, the Lewis Distinguished Paper for 1984 to 1985, which was selected by the Chief Scientist and a research advisory board, is included and so identified.

Heart Pump Design for Cleveland Clinic Foundation

NASA Technical Reports Server (NTRS)

2005-01-01

Through a Lewis CommTech Program project with the Cleveland Clinic Foundation, the NASA Lewis Research Center is playing a key role in the design and development of a permanently implantable, artificial heart pump assist device. Known as the Innovative Ventricular Assist System (IVAS), this device will take on the pumping role of the damaged left ventricle of the heart. The key part of the IVAS is a nonpulsatile (continuous flow) artificial heart pump with centrifugal impeller blades, driven by an electric motor. Lewis is part of an industry and academia team, led by the Ohio Aerospace Institute (OAI), that is working with the Cleveland Clinic Foundation to make IVAS a reality. This device has the potential to save tens of thousands of lives each year, since 80 percent of heart attack victims suffer irreversible damage to the left ventricle, the part of the heart that does most of the pumping. Impeller blade design codes and flow-modeling analytical codes will be used in the project. These codes were developed at Lewis for the aerospace industry but will be applicable to the IVAS design project. The analytical codes, which currently simulate the flow through the compressor and pump systems, will be used to simulate the flow within the blood pump in the artificial heart assist device. The Interdisciplinary Technology Office heads up Lewis' efforts in the IVAS project. With the aid of numerical modeling, the blood pump will address many design issues, including some fluid-dynamic design considerations that are unique to the properties of blood. Some of the issues that will be addressed in the design process include hemolysis, deposition, recirculation, pump efficiency, rotor thrust balance, and bearing lubrication. Optimum pumping system performance will be achieved by modeling all the interactions between the pump components. The interactions can be multidisciplinary and, therefore, are influenced not only by the fluid dynamics of adjacent components but also by thermal and structural effects. Lewis-developed flow-modeling codes to be used in the pump simulations will include a one-dimensional code and an incompressible three-dimensional Navier-Stokes flow code. These codes will analyze the prototype pump designed by the Cleveland Clinic Foundation. With an improved understanding of the flow phenomena within the prototype pump, design changes to improve the performance of the pump system can be verified by computer prior to fabrication in order to reduce risks. The use of Lewis flow modeling codes during the design and development process will improve pump system performance and reduce the number of prototypes built in the development phase. The first phase of the IVAS project is to fully develop the prototype in a laboratory environment that uses a water/glycerin mixture as the surrogate fluid to simulate blood. A later phase of the project will include testing in animals for final validation. Lewis will be involved in the IVAS project for 3 to 5 years.

Microgravity

NASA Image and Video Library

2004-04-15

Combustion Module-1 was one of the most complex and technologically sophisticated pieces of hardware ever to be included as a part of a Spacelab mission. Shown here are the two racks which comprised CM-1, the rack on the right shows the combustion chamber with the Structure Of Flame Balls at Low Lewis-numbers (SOFBALL) experiment inside.

Photocopy of drawing. ALTITUDE CHAMBERS “L” & “R” STRUCTURES. NASA, ...

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

Photocopy of drawing. ALTITUDE CHAMBERS “L” & “R” STRUCTURES. NASA, John F. Kennedy Space Center, Florida. Drawing 68-K-L-11213, NASA KSC, March, 1971. DOOR LATCH MECHANISM & DOOR LATCHING RATCHET. Sheet 14 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

Structure A, architectural sections & details. Drawing no. H2, revised ...

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

Structure A, architectural sections & details. Drawing no. H2, revised as-built dated October 11, 1951. Original drawing by Black & Veatch, consulting engineers, Kansas City, Missouri, prepared for the U.S. Department of the Army, Office of Engineers, Military Construction Division, Washington, D.C. dated October 1. - Travis Air Force Base, Building No. 925, W Street, Fairfield, Solano County, CA

Some effects of sex, age, and household structure on family drawings of Barbadian children.

PubMed

Payne, M A

1996-10-01

An analysis of the family drawings of a nonclinical sample of 502 Barbadian children aged 7-11 years is reported. The inclusion or omission of figures and the size and positioning of the figures of parents and self were examined with reference to sex, age, and household structure. The view that cultural values about the structure of the family unit and parental roles are reflected in children's representations of their parents in family drawings was supported.

Drawing dependent structures, mechanical properties and cyclization behaviors of polyacrylonitrile and polyacrylonitrile/carbon nanotube composite fibers prepared by plasticized spinning.

PubMed

Li, Xiang; Qin, Aiwen; Zhao, Xinzhen; Liu, Dapeng; Wang, Haiye; He, Chunju

2015-09-14

Drawing to change the structural properties and cyclization behaviors of the polyacrylonitrile (PAN) chains in crystalline and amorphous regions is carried out on PAN and PAN/carbon nanotube (CNT) composite fibers. Various characterization methods including Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction and thermal gravimetric analysis are used to monitor the structural evolution and cyclization behaviors of the fibers. With an increase of the draw ratio during the plasticized spinning process, the structural parameters of the fibers, i.e. crystallinity and planar zigzag conformation, are decreased at first, and then increased, which are associated with the heat exchange rate and the oriented-crystallization rate. A possible mechanism for plasticized spinning is proposed to explain the changing trends of crystallinity and planar zigzag conformation. PAN and PAN/CNT fibers exhibit various cyclization behaviors induced by drawing, e.g., the initiation temperature for the cyclization (Ti) of PAN fibers is increased with increasing draw ratio, while Ti of PAN/CNT fibers is decreased. Drawing also facilitates cyclization and lowers the percentage of β-amino nitrile for PAN/CNT fibers during the stabilization.

Solid polymeric electrolytes for lithium batteries

DOEpatents

Angell, Charles A.; Xu, Wu; Sun, Xiaoguang

2006-03-14

Novel conductive polyanionic polymers and methods for their preparion are provided. The polyanionic polymers comprise repeating units of weakly-coordinating anionic groups chemically linked to polymer chains. The polymer chains in turn comprise repeating spacer groups. Spacer groups can be chosen to be of length and structure to impart desired electrochemical and physical properties to the polymers. Preferred embodiments are prepared from precursor polymers comprising the Lewis acid borate tri-coordinated to a selected ligand and repeating spacer groups to form repeating polymer chain units. These precursor polymers are reacted with a chosen Lewis base to form a polyanionic polymer comprising weakly coordinating anionic groups spaced at chosen intervals along the polymer chain. The polyanionic polymers exhibit high conductivity and physical properties which make them suitable as solid polymeric electrolytes in lithium batteries, especially secondary lithium batteries.

Elusive silane-alane complex [Si-H⋅⋅⋅Al]: isolation, characterization, and multifaceted frustrated Lewis pair type catalysis.

PubMed

Chen, Jiawei; Chen, Eugene Y-X

2015-06-01

The super acidity of the unsolvated Al(C6F5)3 enabled isolation of the elusive silane-alane complex [Si-H⋅⋅⋅Al], which was structurally characterized by spectroscopic and X-ray diffraction methods. The Janus-like nature of this adduct, coupled with strong silane activation, effects multifaceted frustrated-Lewis-pair-type catalysis. When compared with the silane-borane system, the silane-alane system offers unique features or clear advantages in the four types of catalytic transformations examined in this study, including: ligand redistribution of tertiary silanes into secondary and quaternary silanes, polymerization of conjugated polar alkenes, hydrosilylation of unactivated alkenes, and hydrodefluorination of fluoroalkanes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method and apparatus for ion sequestration and a nanostructured metal phosphate

DOEpatents

Mattigod, Shas V [Richland, WA; Fryxell, Glen E [Kennewic, WA; Li, Xiaohong [Richland, WA; Parker, Kent E [Kennewick, WA; Wellman, Dawn M [West Richland, WA

2010-04-06

A nanostructured substance, a process for sequestration of ionic waste, and an ion-sequestration apparatus are disclosed in the specification. The nanostructured substance can comprise a Lewis acid transition metal bound to a phosphate, wherein the phosphate comprises a primary structural component of the substance and the Lewis acid transition metal is a reducing agent. The nanostructured substance has a Brunner-Emmet-Teller (BET) surface area greater than or equal to approximately 100 m.sup.2/g, and a distribution coefficient for an analyte, K.sub.d, greater than or equal to approximately 5000 ml/g. The process can comprise contacting a fluid and a nanostructured metal phosphate. The apparatus can comprise a vessel and a nanostructured metal phosphate. The vessel defines a volume wherein a fluid contacts the nanostructured metal phosphate.

NASA Lewis Research Center Workshop on Forced Response in Turbomachinery

NASA Technical Reports Server (NTRS)

Stefko, George L. (Compiler); Murthy, Durbha V. (Compiler); Morel, Michael (Compiler); Hoyniak, Dan (Compiler); Gauntner, Jim W. (Compiler)

1994-01-01

A summary of the NASA Lewis Research Center (LeRC) Workshop on Forced Response in Turbomachinery in August, 1993 is presented. It was sponsored by the following NASA organizations: Structures, Space Propulsion Technology, and Propulsion Systems Divisions of NASA LeRC and the Aeronautics and Advanced Concepts & Technology Offices of NASA Headquarters. In addition, the workshop was held in conjunction with the GUIde (Government/Industry/Universities) Consortium on Forced Response. The workshop was specifically designed to receive suggestions and comments from industry on current research at NASA LeRC in the area of forced vibratory response of turbomachinery blades which includes both computational and experimental approaches. There were eight presentations and a code demonstration. Major areas of research included aeroelastic response, steady and unsteady fluid dynamics, mistuning, and corresponding experimental work.

North American AJ-2 Savage used for Microgravity Flights

NASA Image and Video Library

1960-09-21

The National Aeronautics and Space Administration (NASA) Lewis Research Center acquired two North American AJ-2 Savages in the early 1960s to fly microgravity-inducing parabola flight patterns. Lewis was in the midst of an extensive study to determine the behavior of liquid hydrogen in microgravity so that proper fuel systems could be designed. Jack Enders was the primary pilot for the program and future astronaut Fred Haise worked with the cameras and instrumentation in the rear of the aircraft. North American developed the AJ-2 for the Navy in the mid-1940s as a carrier-based bomber. By the 1960s the Savage was no longer considered a modern aircraft, but its performance capabilities made it appealing to the Lewis researchers. The AJ-2 ‘s power, speed, response time, structural robustness, and large interior space were applicable to the microgravity flights. The AJ-2 could also accommodate a pilot, flight engineer, and two observers. Lewis engineers installed a 100-litre liquid hydrogen dewar, cryogenic cooling system, and cameras in the bomb bay. The AJ-2 was flown on a level course over western Lake Erie then went into a 20-degree dip to generate 375 knot. At 13,000 feet the pilot pulled the nose up by 40 degrees. The speed decreased and both latitudinal and longitudinal accelerations were nullified. Upon reaching 17,000 feet, the pilot turned the aircraft into a 45-degree dive. As the speed reached 390 knots the pilot pulled the aircraft up again. Each maneuver produced approximately 27 seconds of microgravity.

Lysosomes, autophagosomes and Alzheimer pathology in dementia with Lewy body disease.

PubMed

Gurney, Rowan; Davidson, Yvonne S; Robinson, Andrew C; Richardson, Anna; Jones, Matthew; Snowden, Julie S; Mann, David M A

2018-05-10

A failure of protein degradation may underpin Lewy body disease (LBD) where α-synuclein is assimilated into the pathognomic Lewy bodies and Lewy neurites. We investigated histological alterations in lysosomes and autophagosomes in the substantia nigra (SN) and cingulate gyrus (CG) in 34 patients with LBD employing antibodies against phosphorylated α-synuclein and lysosomal (lysosomal associated membrane proteins 1 and 2 (LAMP-1 and LAMP-2), cathepsin D (CTSD)) and autophagosomal (microtubule-associated protein light chain 3α (LC3A)) proteins. Immunostained sections were qualitatively and semi-quantitatively assessed for the appearance, distribution and intensity of staining. Four LBD patients had mutations in GBA1. There was significantly less LAMP-1, LAMP-2 and CTSD immunostaining in neurons of the SN in LBD cases compared to control cases and marginally less LAMP-1 in patients with GBA1 mutations compared to those without. Loss of LAMP-1 and CTSD immunoreactivity correlated with cell loss from the SN. There were no changes in LC3A immunoreactivity in the SN, nor any major changes in the CG, or glial cell activity in the SN and CG, for any of the markers. A proportion of amyloid plaques in both the LBD and control cases was immunoreactive for LAMP-1 and LAMP-2, but not CTSD or LC3A proteins. These immunohisochemical features were seen in glial cells, which were negative for amyloid-β. Alterations in lysosomal structure or function, but not macroautophagy, may underpin the pathogenesis of LBD. © 2018 Japanese Society of Neuropathology.

A LES-CMC formulation for premixed flames including differential diffusion

NASA Astrophysics Data System (ADS)

Farrace, Daniele; Chung, Kyoungseoun; Bolla, Michele; Wright, Yuri M.; Boulouchos, Konstantinos; Mastorakos, Epaminondas

2018-05-01

A finite volume large eddy simulation-conditional moment closure (LES-CMC) numerical framework for premixed combustion developed in a previous studyhas been extended to account for differential diffusion. The non-unity Lewis number CMC transport equation has an additional convective term in sample space proportional to the conditional diffusion of the progress variable, that in turn accounts for diffusion normal to the flame front and curvature-induced effects. Planar laminar simulations are first performed using a spatially homogeneous non-unity Lewis number CMC formulation and validated against physical-space fully resolved reference solutions. The same CMC formulation is subsequently used to numerically investigate the effects of curvature for laminar flames having different effective Lewis numbers: a lean methane-air flame with Leeff = 0.99 and a lean hydrogen-air flame with Leeff = 0.33. Results suggest that curvature does not affect the conditional heat release if the effective Lewis number tends to unity, so that curvature-induced transport may be neglected. Finally, the effect of turbulence on the flame structure is qualitatively analysed using LES-CMC simulations with and without differential diffusion for a turbulent premixed bluff body methane-air flame exhibiting local extinction behaviour. Overall, both the unity and the non-unity computations predict the characteristic M-shaped flame observed experimentally, although some minor differences are identified. The findings suggest that for the high Karlovitz number (from 1 to 10) flame considered, turbulent mixing within the flame weakens the differential transport contribution by reducing the conditional scalar dissipation rate and accordingly the conditional diffusion of the progress variable.

Drawing lithography for microneedles: a review of fundamentals and biomedical applications.

PubMed

Lee, Kwang; Jung, Hyungil

2012-10-01

A microneedle is a three-dimensional (3D) micromechanical structure and has been in the spotlight recently as a drug delivery system (DDS). Because a microneedle delivers the target drug after penetrating the skin barrier, the therapeutic effects of microneedles proceed from its 3D structural geometry. Various types of microneedles have been fabricated using subtractive micromanufacturing methods which are based on the inherently planar two-dimensional (2D) geometries. However, traditional subtractive processes are limited for flexible structural microneedles and makes functional biomedical applications for efficient drug delivery difficult. The authors of the present study propose drawing lithography as a unique additive process for the fabrication of a microneedle directly from 2D planar substrates, thus overcoming a subtractive process shortcoming. The present article provides the first overview of the principal drawing lithography technology: fundamentals and biomedical applications. The continuous drawing technique for an ultrahigh-aspect ratio (UHAR) hollow microneedle, stepwise controlled drawing technique for a dissolving microneedle, and drawing technique with antidromic isolation for a hybrid electro-microneedle (HEM) are reviewed, and efficient biomedical applications by drawing lithography-mediated microneedles as an innovative drug and gene delivery system are described. Drawing lithography herein can provide a great breakthrough in the development of materials science and biotechnology. Copyright © 2012 Elsevier Ltd. All rights reserved.

A laser-based ice shape profilometer for use in icing wind tunnels

NASA Technical Reports Server (NTRS)

Hovenac, Edward A.; Vargas, Mario

1995-01-01

A laser-based profilometer was developed to measure the thickness and shape of ice accretions on the leading edge of airfoils and other models in icing wind tunnels. The instrument is a hand held device that is connected to a desk top computer with a 10 meter cable. It projects a laser line onto an ice shape and used solid state cameras to detect the light scattered by the ice. The instrument corrects the image for camera angle distortions, displays an outline of the ice shape on the computer screen, saves the data on a disk, and can print a full scale drawing of the ice shape. The profilometer has undergone extensive testing in the laboratory and in the NASA Lewis Icing Research Tunnel. Results of the tests show very good agreement between profilometer measurements and known simulated ice shapes and fair agreement between profilometer measurements and hand tracing techniques.

An Electronic Pressure Profile Display system for aeronautic test facilities

NASA Technical Reports Server (NTRS)

Woike, Mark R.

1990-01-01

The NASA Lewis Research Center has installed an Electronic Pressure Profile Display system. This system provides for the real-time display of pressure readings on high resolution graphics monitors. The Electronic Pressure Profile Display system will replace manometer banks currently used in aeronautic test facilities. The Electronic Pressure Profile Display system consists of an industrial type Digital Pressure Transmitter (DPI) unit which interfaces with a host computer. The host computer collects the pressure data from the DPI unit, converts it into engineering units, and displays the readings on a high resolution graphics monitor in bar graph format. Software was developed to accomplish the above tasks and also draw facility diagrams as background information on the displays. Data transfer between host computer and DPT unit is done with serial communications. Up to 64 channels are displayed with one second update time. This paper describes the system configuration, its features, and its advantages over existing systems.

An electronic pressure profile display system for aeronautic test facilities

NASA Technical Reports Server (NTRS)

Woike, Mark R.

1990-01-01

The NASA Lewis Research Center has installed an Electronic Pressure Profile Display system. This system provides for the real-time display of pressure readings on high resolution graphics monitors. The Electronic Pressure Profile Display system will replace manometer banks currently used in aeronautic test facilities. The Electronic Pressure Profile Display system consists of an industrial type Digital Pressure Transmitter (DPT) unit which interfaces with a host computer. The host computer collects the pressure data from the DPT unit, converts it into engineering units, and displays the readings on a high resolution graphics monitor in bar graph format. Software was developed to accomplish the above tasks and also draw facility diagrams as background information on the displays. Data transfer between host computer and DPT unit is done with serial communications. Up to 64 channels are displayed with one second update time. This paper describes the system configuration, its features, and its advantages over existing systems.

Bernard Lewis: An Appreciation.

ERIC Educational Resources Information Center

Humphreys, R. Stephen

1990-01-01

Discusses the career and publications of Bernard Lewis, a noted scholar in the field of Middle-Eastern studies and Islamic history. Traces the history of Western-based Islamic historiography. Examines Lewis' interpretation of Islamic history, outlining his political and social views. (RW)

Lewis Research Center: Commercialization Success Stories

NASA Technical Reports Server (NTRS)

Heyward, Ann O.

1996-01-01

The NASA Lewis Research Center, located in Cleveland, Ohio, has a portfolio of research and technology capabilities and facilities that afford opportunities for productive partnerships with industry in a broad range of industry sectors. In response to the President's agenda in the area of technology for economic growth (Clinton/Gore 1993), the National Performance Review (1993), NASA's Agenda for Change (1994), and the needs of its customers, NASA Lewis Research Center has sought and achieved significant successes in technology transfer and commercialization. This paper discusses a sampling of Lewis Research Center's successes in this area, and lessons learned that Lewis Research Center is applying in pursuit of continuous improvement and excellence in technology transfer and commercialization.

Changing Attitudes Toward Devotion and Duty in Western Literature

DTIC Science & Technology

1990-05-22

Allegory of Love ..... ............... 36 Lewis and Chr6tien de Troyes ... ........... 44 Lewis on Andreas Capellanus ... ........... 47 Denis de Rougemont...century French poetry, including that of Chr~tien de Troyes . Lewis and Chr~tien de Troyes Lewis describes the works of Chr~tien as among the most...poetry of Chr~tien de Troyes . At this early stage of the allegorical tradition, Chr~tien is credited with having been "one of the first explorers of the

Drawing on the right side of the brain: a voxel-based morphometry analysis of observational drawing.

PubMed

Chamberlain, Rebecca; McManus, I Chris; Brunswick, Nicola; Rankin, Qona; Riley, Howard; Kanai, Ryota

2014-08-01

Structural brain differences in relation to expertise have been demonstrated in a number of domains including visual perception, spatial navigation, complex motor skills and musical ability. However no studies have assessed the structural differences associated with representational skills in visual art. As training artists are inclined to be a heterogeneous group in terms of their subject matter and chosen media, it was of interest to investigate whether there would be any consistent changes in neural structure in response to increasing representational drawing skill. In the current study a cohort of 44 graduate and post-graduate art students and non-art students completed drawing tasks. Scores on these tasks were then correlated with the regional grey and white matter volume in cortical and subcortical structures. An increase in grey matter density in the left anterior cerebellum and the right medial frontal gyrus was observed in relation to observational drawing ability, whereas artistic training (art students vs. non-art students) was correlated with increased grey matter density in the right precuneus. This suggests that observational drawing ability relates to changes in structures pertaining to fine motor control and procedural memory, and that artistic training in addition is associated with enhancement of structures pertaining to visual imagery. The findings corroborate the findings of small-scale fMRI studies and provide insights into the properties of the developing artistic brain. Copyright © 2014 Elsevier Inc. All rights reserved.

Engine Structures Modeling Software System (ESMOSS)

NASA Technical Reports Server (NTRS)

1991-01-01

Engine Structures Modeling Software System (ESMOSS) is the development of a specialized software system for the construction of geometric descriptive and discrete analytical models of engine parts, components, and substructures which can be transferred to finite element analysis programs such as NASTRAN. The NASA Lewis Engine Structures Program is concerned with the development of technology for the rational structural design and analysis of advanced gas turbine engines with emphasis on advanced structural analysis, structural dynamics, structural aspects of aeroelasticity, and life prediction. Fundamental and common to all of these developments is the need for geometric and analytical model descriptions at various engine assembly levels which are generated using ESMOSS.

26. "TEST STAND, STRUCTURAL, FOUNDATION PLAN." Specifications No. ENG043535572; Drawing ...

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

26. "TEST STAND, STRUCTURAL, FOUNDATION PLAN." Specifications No. ENG-04-353-55-72; Drawing No. 60-0912; sheet 25 of 148; file no. 1320/76. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract no. 4338, no change. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

Structure A, protective alarm installation details. Drawing no. H3709, revised ...

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

Structure A, protective alarm installation details. Drawing no. H3-709, revised as-built dated August 28, 1952. Original drawing by Black & Veatch, consulting engineers, Kansas City, Missouri, prepared for the U.S. Department of the Army, Office of Engineers, Military Construction Division, Washington, D.C. dated October 1, 1951. - Travis Air Force Base, Building No. 925, W Street, Fairfield, Solano County, CA

Structure A, dock reinforcing & bill of material. Drawing no. ...

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

Structure A, dock reinforcing & bill of material. Drawing no. H2-306, revised as-built dated August 13, 1953. Original drawing by Black & Veatch, consulting engineers, Kansas City, Missouri, prepared for the U.S. Department of the Army, Office of Engineers, Military Construction Division, Washington, D.C. dated October 1, 1951. - Travis Air Force Base, Building No. 925, W Street, Fairfield, Solano County, CA

Thermal degradation of Lewis acid complexed LDPE films

NASA Astrophysics Data System (ADS)

Sreelatha, K.; Predeep, P.

2017-06-01

The study highlights the thermal behavior of the semiconducting LDPE films synthesized by SbCl5 doping. The structural peculiarities and the responses of the structure to energetic modifications are studied. TGA and DTG curves are used to determine the thermal stability of the material. Degradation kinetics is elucidated. Activation energy and the entropy of activation for the degradation of the samples are calculated using Coats-Redfern plots and the samples show appreciable thermal stability.

R2R--software to speed the depiction of aesthetic consensus RNA secondary structures.

PubMed

Weinberg, Zasha; Breaker, Ronald R

2011-01-04

With continuing identification of novel structured noncoding RNAs, there is an increasing need to create schematic diagrams showing the consensus features of these molecules. RNA structural diagrams are typically made either with general-purpose drawing programs like Adobe Illustrator, or with automated or interactive programs specific to RNA. Unfortunately, the use of applications like Illustrator is extremely time consuming, while existing RNA-specific programs produce figures that are useful, but usually not of the same aesthetic quality as those produced at great cost in Illustrator. Additionally, most existing RNA-specific applications are designed for drawing single RNA molecules, not consensus diagrams. We created R2R, a computer program that facilitates the generation of aesthetic and readable drawings of RNA consensus diagrams in a fraction of the time required with general-purpose drawing programs. Since the inference of a consensus RNA structure typically requires a multiple-sequence alignment, the R2R user annotates the alignment with commands directing the layout and annotation of the RNA. R2R creates SVG or PDF output that can be imported into Adobe Illustrator, Inkscape or CorelDRAW. R2R can be used to create consensus sequence and secondary structure models for novel RNA structures or to revise models when new representatives for known RNA classes become available. Although R2R does not currently have a graphical user interface, it has proven useful in our efforts to create 100 schematic models of distinct noncoding RNA classes. R2R makes it possible to obtain high-quality drawings of the consensus sequence and structural models of many diverse RNA structures with a more practical amount of effort. R2R software is available at http://breaker.research.yale.edu/R2R and as an Additional file.

Lewy body dementia--clinical, pathological and neurochemical interconnections.

PubMed

Perry, R; McKeith, I; Perry, E

1997-01-01

Senile dementia of Lewy body type or Lewy body dementia (SDLT or LBD) is defined as a Lewy body associated disease presenting in the elderly primarily with dementia with variable extrapyramidal disorder. Characteristic clinical symptoms include fluctuating cognitive impairment, psychotic features such as hallucinations and a particular sensitivity to neuroleptic medication. Although apolipoprotein e4 allele is increased 2-3 fold in SDLT (as in Alzheimer's disease) and beta-amyloidosis occurs in most cases, the most robust neurobiological correlate of the dementia so far identified appears to be extensive cholinergic deficits in the neocortex. This is consistent with previously reported correlations between cortical cholinergic activity and dementia in Parkinson's disease (PD) and Alzheimer's disease. There is also a significant interaction between the density of limbic cortical Lewy bodies and dementia in both SDLT and PD, although the cortical neuronal population affected remains to be identified. Cortical Lewy body density is positively correlated with the age of disease onset in PD and SDLT. This may account for the increased incidence of psychiatric syndromes, as opposed to extrapyramidal disorder in Lewy body disease with advancing age as may age-related loss of cholinergic activity in cortical areas such as the hippocampus.

Liquid-Phase Catalytic Transfer Hydrogenation of Furfural over Homogeneous Lewis Acid-Ru/C Catalysts.

PubMed

Panagiotopoulou, Paraskevi; Martin, Nickolas; Vlachos, Dionisios G

2015-06-22

The catalytic performance of homogeneous Lewis acid catalysts and their interaction with Ru/C catalyst are studied in the catalytic transfer hydrogenation of furfural by using 2-propanol as a solvent and hydrogen donor. We find that Lewis acid catalysts hydrogenate the furfural to furfuryl alcohol, which is then etherified with 2-propanol. The catalytic activity is correlated with an empirical scale of Lewis acid strength and exhibits a volcano behavior. Lanthanides are the most active, with DyCl3 giving complete furfural conversion and a 97 % yield of furfuryl alcohol at 180 °C after 3 h. The combination of Lewis acid and Ru/C catalysts results in synergy for the stronger Lewis acid catalysts, with a significant increase in the furfural conversion and methyl furan yield. Optimum results are obtained by using Ru/C combined with VCl3 , AlCl3 , SnCl4 , YbCl3 , and RuCl3 . Our results indicate that the combination of Lewis acid/metal catalysts is a general strategy for performing tandem reactions in the upgrade of furans. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

35. MISCELLANEOUS ARCHITECTURAL AND STRUCTURAL DETAILS. INEEL DRAWING NUMBER 200063300287106359. ...

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

35. MISCELLANEOUS ARCHITECTURAL AND STRUCTURAL DETAILS. INEEL DRAWING NUMBER 200-0633-00-287-106359. FLUOR NUMBER 5775-CPP-633-A-9. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Lewis Incubator for Technology (LIFT)

NASA Technical Reports Server (NTRS)

Zeman, Wayne P.; King, Joseph B.; Jankura, Richard E., Jr.

2004-01-01

This report summarizes the work done to operate the Lewis Incubator for Technology for the period October 2000 through September 2004. The Lewis Incubator helped the startup and growth of technology based businesses with the potential to incorporate technology from the NASA Glenn Research Center.

Cooperative Lewis pairs based on late transition metals: activation of small molecules by platinum(0) and B(C6 F5 )3.

PubMed

Forrest, Sebastian J K; Clifton, Jamie; Fey, Natalie; Pringle, Paul G; Sparkes, Hazel A; Wass, Duncan F

2015-02-09

A Lewis basic platinum(0)-CO complex supported by a diphosphine ligand and B(C6 F5 )3 act cooperatively, in a manner reminiscent of a frustrated Lewis pair, to activate small molecules such as hydrogen, CO2 , and ethene. This cooperative Lewis pair facilitates the coupling of CO and ethene in a new way. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Relationship of Drawing and Mathematical Problem Solving: "Draw for Math" Tasks

ERIC Educational Resources Information Center

Edens, Kellah; Potter, Ellen

2007-01-01

This study examines a series of children's drawings ("Draw for Math" tasks) to determine the relationship of students' spatial understanding and mathematical problem solving. Level of spatial understanding was assessed by applying the framework of central conceptual structures suggested by Case (1996), a cognitive developmental researcher.…

NASA Engineer Examines the Design of a Regeneratively-Cooled Rocket Engine

NASA Image and Video Library

1958-12-21

An engineer at the National Aeronautics and Space Administration (NASA) Lewis Research Center examines a drawing showing the assembly and details of a 20,000-pound thrust regeneratively cooled rocket engine. The engine was being designed for testing in Lewis’ new Rocket Engine Test Facility, which began operating in the fall of 1957. The facility was the largest high-energy test facility in the country that was capable of handling liquid hydrogen and other liquid chemical fuels. The facility’s use of subscale engines up to 20,000 pounds of thrust permitted a cost-effective method of testing engines under various conditions. The Rocket Engine Test Facility was critical to the development of the technology that led to the use of hydrogen as a rocket fuel and the development of lightweight, regeneratively-cooled, hydrogen-fueled rocket engines. Regeneratively-cooled engines use the cryogenic liquid hydrogen as both the propellant and the coolant to prevent the engine from burning up. The fuel was fed through rows of narrow tubes that surrounded the combustion chamber and nozzle before being ignited inside the combustion chamber. The tubes are visible in the liner sitting on the desk. At the time, Pratt and Whitney was designing a 20,000-pound thrust liquid-hydrogen rocket engine, the RL-10. Two RL-10s would be used to power the Centaur second-stage rocket in the 1960s. The successful development of the Centaur rocket and the upper stages of the Saturn V were largely credited to the work carried out Lewis.

Lewis Acid-Assisted Photoinduced Intermolecular Coupling between Acylsilanes and Aldehydes: A Formal Cross Benzoin-Type Condensation.

PubMed

Ishida, Kento; Tobita, Fumiya; Kusama, Hiroyuki

2018-01-12

Intermolecular carbon-carbon bond-forming reaction between readily available acylsilanes and aldehydes was achieved under photoirradiation conditions with assistance of a catalytic amount of Lewis acid. Nucleophilic addition of photochemically generated siloxycarbenes to aldehydes followed by 1,4-silyl migration afforded synthetically useful α-siloxyketones. Electrophilic activation of aldehydes by Lewis acid is highly important to realize this reaction efficiently, otherwise the yield of the desired coupling products were significantly decreased. Noteworthy is that a formal cross benzoin-type reaction using acylsilanes was achieved under Lewis acidic conditions. This is the first example of Lewis acid-catalyzed reaction of photochemically generated siloxycarbenes with electrophiles. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Computing Robust, Bootstrap-Adjusted Fit Indices for Use with Nonnormal Data

ERIC Educational Resources Information Center

Walker, David A.; Smith, Thomas J.

2017-01-01

Nonnormality of data presents unique challenges for researchers who wish to carry out structural equation modeling. The subsequent SPSS syntax program computes bootstrap-adjusted fit indices (comparative fit index, Tucker-Lewis index, incremental fit index, and root mean square error of approximation) that adjust for nonnormality, along with the…

Small mammals in oak woodlands in the Puget Trough, Washington.

Treesearch

S.M. Wilson; A.B. Carey

2001-01-01

We surveyed the 22 largest sites dominated by Oregon white oaks on the Fort Lewis Military Reservation, Washington, to determine small-mammal community structure and population abundances. Study areas were in the Puget Trough physiographic province and western hemlock vegetation zone. Most oak communities were ecotonal between prairie and Douglas-fir forest. Small...

Research and Technology 1990

NASA Technical Reports Server (NTRS)

1990-01-01

A brief but comprehensive review is given of the technical accomplishments of the NASA Lewis Research Center during the past year. Topics covered include instrumentation and controls technology; internal fluid dynamics; aerospace materials, structures, propulsion, and electronics; space flight systems; cryogenic fluids; Space Station Freedom systems engineering, photovoltaic power module, electrical systems, and operations; and engineering and computational support.

Independent Media, Youth Agency, and the Promise of Media Education

ERIC Educational Resources Information Center

Poyntz, Stuart R.

2006-01-01

Through a discussion of two videos--The Take (Naomi Klein & Avi Lewis, 2004), and a student project--I argue that media education can further the role of youth as critically engaged, democratic citizens most effectively when educators develop students' capacity for reflection and self-expression through engagement with those power structures that…

Structural and functional properties of prefibrillar α-synuclein oligomers.

PubMed

Pieri, Laura; Madiona, Karine; Melki, Ronald

2016-04-14

The deposition of fibrillar alpha-synuclein (α-syn) within inclusions (Lewy bodies and Lewy neurites) in neurons and glial cells is a hallmark of synucleinopathies. α-syn populates a variety of assemblies ranging from prefibrillar oligomeric species to fibrils whose specific contribution to neurodegeneration is still unclear. Here, we compare the specific structural and biological properties of distinct soluble prefibrillar α-syn oligomers formed either spontaneously or in the presence of dopamine and glutaraldehyde. We show that both on-fibrillar assembly pathway and distinct dopamine-mediated and glutaraldehyde-cross-linked α-syn oligomers are only slightly effective in perturbing cell membrane integrity and inducing cytotoxicity, while mature fibrils exhibit the highest toxicity. In contrast to low-molecular weight and unstable oligomers, large stable α-syn oligomers seed the aggregation of soluble α-syn within reporter cells although to a lesser extent than mature α-syn fibrils. These oligomers appear elongated in shape. Our findings suggest that α-syn oligomers represent a continuum of species ranging from unstable low molecular weight particles to mature fibrils via stable elongated oligomers composed of more than 15 α-syn monomers that possess seeding capacity.

NASA Lewis steady-state heat pipe code users manual

NASA Technical Reports Server (NTRS)

Tower, Leonard K.; Baker, Karl W.; Marks, Timothy S.

1992-01-01

The NASA Lewis heat pipe code was developed to predict the performance of heat pipes in the steady state. The code can be used as a design tool on a personal computer or with a suitable calling routine, as a subroutine for a mainframe radiator code. A variety of wick structures, including a user input option, can be used. Heat pipes with multiple evaporators, condensers, and adiabatic sections in series and with wick structures that differ among sections can be modeled. Several working fluids can be chosen, including potassium, sodium, and lithium, for which monomer-dimer equilibrium is considered. The code incorporates a vapor flow algorithm that treats compressibility and axially varying heat input. This code facilitates the determination of heat pipe operating temperatures and heat pipe limits that may be encountered at the specified heat input and environment temperature. Data are input to the computer through a user-interactive input subroutine. Output, such as liquid and vapor pressures and temperatures, is printed at equally spaced axial positions along the pipe as determined by the user.

NASA Lewis steady-state heat pipe code users manual

NASA Astrophysics Data System (ADS)

Tower, Leonard K.; Baker, Karl W.; Marks, Timothy S.

1992-06-01

The NASA Lewis heat pipe code was developed to predict the performance of heat pipes in the steady state. The code can be used as a design tool on a personal computer or with a suitable calling routine, as a subroutine for a mainframe radiator code. A variety of wick structures, including a user input option, can be used. Heat pipes with multiple evaporators, condensers, and adiabatic sections in series and with wick structures that differ among sections can be modeled. Several working fluids can be chosen, including potassium, sodium, and lithium, for which monomer-dimer equilibrium is considered. The code incorporates a vapor flow algorithm that treats compressibility and axially varying heat input. This code facilitates the determination of heat pipe operating temperatures and heat pipe limits that may be encountered at the specified heat input and environment temperature. Data are input to the computer through a user-interactive input subroutine. Output, such as liquid and vapor pressures and temperatures, is printed at equally spaced axial positions along the pipe as determined by the user.

Enhanced conformational sampling of carbohydrates by Hamiltonian replica-exchange simulation.

PubMed

Mishra, Sushil Kumar; Kara, Mahmut; Zacharias, Martin; Koca, Jaroslav

2014-01-01

Knowledge of the structure and conformational flexibility of carbohydrates in an aqueous solvent is important to improving our understanding of how carbohydrates function in biological systems. In this study, we extend a variant of the Hamiltonian replica-exchange molecular dynamics (MD) simulation to improve the conformational sampling of saccharides in an explicit solvent. During the simulations, a biasing potential along the glycosidic-dihedral linkage between the saccharide monomer units in an oligomer is applied at various levels along the replica runs to enable effective transitions between various conformations. One reference replica runs under the control of the original force field. The method was tested on disaccharide structures and further validated on biologically relevant blood group B, Lewis X and Lewis A trisaccharides. The biasing potential-based replica-exchange molecular dynamics (BP-REMD) method provided a significantly improved sampling of relevant conformational states compared with standard continuous MD simulations, with modest computational costs. Thus, the proposed BP-REMD approach adds a new dimension to existing carbohydrate conformational sampling approaches by enhancing conformational sampling in the presence of solvent molecules explicitly at relatively low computational cost.

Advances in Thin Film Sensor Technologies for Engine Applications

NASA Technical Reports Server (NTRS)

Lei, Jih-Fen; Martin, Lisa C.; Will, Herbert A.

1997-01-01

Advanced thin film sensor techniques that can provide accurate surface strain and temperature measurements are being developed at NASA Lewis Research Center. These sensors are needed to provide minimally intrusive characterization of advanced materials (such as ceramics and composites) and structures (such as components for Space Shuttle Main Engine, High Speed Civil Transport, Advanced Subsonic Transports and General Aviation Aircraft) in hostile, high-temperature environments and for validation of design codes. This paper presents two advanced thin film sensor technologies: strain gauges and thermocouples. These sensors are sputter deposited directly onto the test articles and are only a few micrometers thick; the surface of the test article is not structurally altered and there is minimal disturbance of the gas flow over the surface. The strain gauges are palladium-13% chromium based and the thermocouples are platinum-13% rhodium vs. platinum. The fabrication techniques of these thin film sensors in a class 1000 cleanroom at the NASA Lewis Research Center are described. Their demonstration on a variety of engine materials, including superalloys, ceramics and advanced ceramic matrix composites, in several hostile, high-temperature test environments are discussed.

Lewis acid-Lewis acid heterobimetallic cooperative catalysis: mechanistic studies and application in enantioselective aza-Michael reaction.

PubMed

Yamagiwa, Noriyuki; Qin, Hongbo; Matsunaga, Shigeki; Shibasaki, Masakatsu

2005-09-28

The full details of a catalytic asymmetric aza-Michael reaction of methoxylamine promoted by rare earth-alkali metal heterobimetallic complexes are described, demonstrating the effectiveness of Lewis acid-Lewis acid cooperative catalysis. First, enones were used as substrates, and the 1,4-adducts were obtained in good yield (57-98%) and high ee (81-96%). Catalyst loading was successfully reduced to 0.3-3 mol % with enones. To broaden the substrate scope of the reaction to carboxylic acid derivatives, alpha,beta-unsaturated N-acylpyrroles were used as monodentate, carboxylic acid derivatives. With beta-alkyl-substituted N-acylpyrroles, the reaction proceeded smoothly and the products were obtained in high yield and good ee. Transformation of the 1,4-adducts from enones and alpha,beta-unsaturated N-acylpyrroles afforded corresponding chiral aziridines and beta-amino acids. Detailed mechanistic studies, including kinetics, NMR analysis, nonlinear effects, and rare earth metal effects, are also described. The Lewis acid-Lewis acid cooperative mechanism, including the substrate coordination mode, is discussed in detail.

Research and Technology 1995

NASA Technical Reports Server (NTRS)

1996-01-01

This report selectively summarizes the NASA Lewis Research Center's research and technology accomplishments for fiscal year 1995. It comprises over 150 short articles submitted by the staff members of the technical directorates. The report is organized into six major sections: aeronautics, aerospace technology, space flight systems, engineering support, Lewis Research Academy, and technology transfer. A table of contents, an author index, and a list of NASA Headquarters program offices have been included to assist the reader in finding articles of special interest. This report is not intended to be a comprehensive summary of all research and technology work done over the past fiscal year. Most of the work is reported in Lewis-published technical reports, journal articles, and presentations prepared by Lewis staff members and contractors (for abstracts of these Lewis-authored reports, visit the Lewis Technical Report Server (LETRS) on the World Wide Web-http://letrs.lerc.nasa.gov/LeTRS/). In addition, university grants have enabled faculty members and graduate students to engage in sponsored research that is reported at technical meetings or in journal articles. For each article in this report, a Lewis contact person has been identified, and where possible, reference documents are listed so that additional information can be easily obtained. The diversity of topics attests to the breadth of research and technology being pursued and to the skill mix of the staff that makes it possible. For more information about Lewis' research, visit us on the World Wide web-http://www.lerc.nasa.gov.

George Lewis Addresses Staff during the Construction of the New Laboratory

NASA Image and Video Library

1942-05-21

Construction Manager Raymond Sharp and the National Advisory Committee for Aeronautics (NACA) Director of Research George Lewis speak to employees during the May 8, 1942, Initiation of Research ceremony at the Aircraft Engine Research Laboratory. The event marked the first operation of a test facility at the new laboratory. The overall laboratory was still under construction, however, and behind schedule. Lewis traveled from his office in Washington, DC every week to personally assess the progress. Drastic measures were undertaken to accelerate the lab’s construction schedule. The military provided special supplies, contractors were given new agreements and pressured to meet deadlines, and Congress approved additional funds. The effort paid off and much of the laboratory was operational in early 1943. George Lewis managed the NACA’s aeronautical research for over 20 years. Lewis joined the NACA as Executive Officer in 1919, and was named Director of Aeronautical Research in 1924. In this role Lewis served as the liaison between the Executive Committee and the research laboratories. His most important accomplishment may have been the investigative tours of the research facilities in Germany in 1936 and 1939. The visits resulted in the NACA’s physical expansion and the broadening of the scope of its research. Lewis did not take a day of leave between the Pearl Harbor attack and the Armistice. He began suffering health problems in 1945 and was forced to retire two years later. The Aircraft Engine Research Laboratory was renamed the NACA Lewis Flight Propulsion Laboratory in September 1948.

Mercury Capsule Construction at the NASA Lewis Research Center

NASA Image and Video Library

1959-08-21

A NASA mechanic secures the afterbody to a Mercury capsule in the hangar at the Lewis Research Center. The capsule was one of two built at Lewis for the “Big Joe” launches scheduled for September 1959. The initial phase of Project Mercury consisted of a series of unmanned launches using the Air Force’s Redstone and Atlas boosters and the Langley-designed Little Joe boosters. The first Atlas launch, referred to as “Big Joe”, was a single attempt early in Project Mercury to use a full-scale Atlas booster to simulate the reentry of a mock-up Mercury capsule without actually placing it in orbit. The overall design of Big Joe had been completed by December 1958, and soon thereafter project manager Aleck Bond assigned NASA Lewis the task of designing the electronic instrumentation and automatic stabilization system. Lewis also constructed the capsule’s lower section, which contained a pressurized area with the electronics and two nitrogen tanks for the retrorockets. Lewis technicians were responsible for assembling the entire capsule: the General Electric heatshield, NASA Langley afterbody and recovery canister, and Lewis electronics and control systems. On June 9, 1959, the capsule was loaded on an air force transport aircraft and flown to Cape Canaveral. A team of 45 test operations personnel from Lewis followed the capsule to Florida and spent the ensuing months preparing it for launch. The launch took place in the early morning hours of September 9, 1959.

An electromechanical actuation system for an expendable launch vehicle

NASA Technical Reports Server (NTRS)

Burrows, Linda M.; Roth, Mary E.

1992-01-01

A major effort at NASA-Lewis in recent years has been to develop electro-mechanical actuators (EMA's) to replace the hydraulic systems used for thrust vector control (TVC) on launch vehicles. This is an attempt to overcome the inherent inefficiencies and costs associated with the existing hydraulic structures. General Dynamics Space Systems Division, under contract to NASA Lewis, is developing 18.6 kW (25 hp), 29.8 kW (40 hp), and 52.2 kW (70 hp) peak EMA systems to meet the power demands for TVC on a family of vehicles developed for the National Launch System. These systems utilize a pulse population modulated converter and field-oriented control scheme to obtain independent control of both the voltage and frequency. These techniques allow an induction motor to be operated at its maximum torque at all times.

NASA Has Joined America True's Design Mission for 2000

NASA Technical Reports Server (NTRS)

Steele, Gynelle C.

1999-01-01

Engineers at the NASA Lewis Research Center will support the America True design team led by America s Cup innovator Phil Kaiko. The joint effort between NASA and America True is encouraged by Mission HOME, the official public awareness campaign of the U.S. space community. NASA Lewis and America True have entered into a Space Act Agreement to focus on the interaction between the airfoil and the large deformation of the pretensioned sails and rigs along with the dynamic motions related to the boat motions. This work will require a coupled fluid and structural simulation. Included in the simulation will be both a steadystate capability, to capture the quasi-state interactions between the air loads and sail geometry and the lift and drag on the boat, and a transient capability, to capture the sail/mast pumping effects resulting from hull motions.

Establishing effective working relations with a potential user community - NASA Lewis Research Center experience

NASA Technical Reports Server (NTRS)

Foster, P.

1977-01-01

The NASA Lewis Research Center has held a series of six major and unique technology utilization conferences which were major milestones in planned structured efforts to establish effective working relationships with specific technology user communities. These efforts were unique in that the activities undertaken prior to the conference were extensive, and effectively laid the groundwork for productive technology transfer following, and as a direct result of, the conferences. The effort leading to the conference was in each case tailored to the characteristics of the potential user community, however, the common factors comprise a basic framework applicable to similar endeavors. The process is essentially a planned sequence of steps that constitute a technical market survey and a marketing program for the development of beneficial applications of aerospace technology beyond the aerospace field.

CuCl2 for the isolation of a broad array of endohedral fullerenes containing metallic, metallic carbide, metallic nitride, and metallic oxide clusters, and separation of their structural isomers.

PubMed

Stevenson, Steven; Rottinger, Khristina A

2013-08-19

A typical arc-synthesis generates many types of fullerenes and endohedrals. Resulting soot extracts contain a complex mixture of >50 types of fullerenes, metallofullerenes, and their structural isomers. Prior to application development, novel separation methods are required to fractionate this rich array of metallic, metallic carbide, metallic nitride, and metallic oxide endohedrals, all of which can be present in a single, soot extract. Herein, we report the discovery of CuCl2 as a Lewis acid that will selectively precipitate only the more reactive members of each of these endohedral families. The more reactive Sc4O2@Ih-C80, Sc3C2@Ih-C80, and Sc3N@D3h-C78 endohedrals are quickly removed from extracts to greatly decrease the number of endohedrals present in a sample. Experiments indicate that enrichment factors of several orders of magnitude can be achieved within minutes of reaction time. CuCl2 also has sufficient selectivity to resolve and separate structural isomers, as demonstrated with Er2@C82 (isomer I, Cs(6)-C82 versus isomer III). The selective complexation of CuCl2 with fullerenes can be correlated to their first oxidation potential. We estimate a significantly lower threshold of precipitation for CuCl2 (<0.19 V) compared to stronger Lewis acids. Fullerenes and metallofullerenes having first oxidation potentials above 0.19 V tend to remain unreacted in solution. In contrast, species with first oxidation potentials below 0.19 V (vs Fc/Fc(+)) precipitate via complexation, and are easily decomplexed. CuCl2 is compared to Lewis acids having higher precipitation thresholds (e.g., FeCl3) in our goal to predict a priori which endohedrals would remain in solution versus which endohedral species would complex and precipitate. The ability to predict endohedral precipitation a priori is beneficial to the design of purification strategies for metallofullerenes.

Advanced High-Temperature Engine Materials Technology Progresses

NASA Technical Reports Server (NTRS)

1995-01-01

The objective of the Advanced High Temperature Engine Materials Technology Program (HITEMP) is to generate technology for advanced materials and structural analysis that will increase fuel economy, improve reliability, extend life, and reduce operating costs for 21st century civil propulsion systems. The primary focus is on fan and compressor materials (polymer-matrix composites--PMC's), compressor and turbine materials (superalloys, and metal-matrix and intermetallic-matrix composites--MMC's and IMC's) and turbine materials (ceramic-matrix composites--CMC's). These advanced materials are being developed by in-house researchers and on grants and contracts. NASA considers this program to be a focused materials and structures research effort that builds on our base research programs and supports component-development projects. HITEMP is coordinated with the Advanced Subsonic Technology (AST) Program and the Department of Defense/NASA Integrated High-Performance Turbine Engine Technology (IHPTET) Program. Advanced materials and structures technologies from HITEMP may be used in these future applications. Recent technical accomplishments have not only improved the state-of-the-art but have wideranging applications to industry. A high-temperature thin-film strain gage was developed to measure both dynamic and static strain up to 1100 C (2000 F). The gage's unique feature is that it is minimally intrusive. This technology, which received a 1995 R&D 100 Award, has been transferred to AlliedSignal Engines, General Electric Company, and Ford Motor Company. Analytical models developed at the NASA Lewis Research Center were used to study Textron Specialty Materials' manufacturing process for titanium-matrix composite rings. Implementation of our recommendations on tooling and processing conditions resulted in the production of defect free rings. In the Lincoln Composites/AlliedSignal/Lewis cooperative program, a composite compressor case is being manufactured with a Lewis-developed matrix, VCAP. The compressor case, which will reduce weight by 30 percent and costs by 50 percent, is scheduled to be engine tested in the near future.

120. Photocopy of drawing (1958 civil engineering drawing by the ...

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

120. Photocopy of drawing (1958 civil engineering drawing by the Ralph M. Parsons Company) STRUCTURAL DETAILS OF WAVE GUIDE ENCLOSURE AND CABLE TRAY INSTALLATION FOR LAUNCH OPERATIONS BUILDING, SHEET C42 - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Drawing cure: children's drawings as a psychoanalytic instrument.

PubMed

Wittmann, Barbara

2010-01-01

This essay deals with the special case of drawings as psychoanalytical instruments. It aims at a theoretical understanding of the specific contribution made by children's drawings as a medium of the psychical. In the influential play technique developed by Melanie Klein, drawing continuously interacts with other symptomatic (play) actions. Nonetheless, specific functions of drawing within the play technique can be identified. The essay will discuss four crucial aspects in-depth: 1) the strengthening of the analysis's recursivity associated with the graphic artifact; 2) the opening of the analytic process facilitated by drawing; 3) the creation of a genuinely graphic mode of producing meaning that allows the child to develop a "theory" of the workings of his own psychic apparatus; and 4) the new possibilities of symbolization associated with the latter. In contrast to classical definitions of the psychological instrument, the child's drawing is a weakly structured tool that does not serve to reproduce psychic processes in an artificial, controlled setting. The introduction of drawing into the psychoanalytic cure is by no means interested in replaying past events, but in producing events suited to effecting a transformation of the synchronic structures of the unconscious.

72. SAC control center underground structure lower floor plan, drawing ...

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

72. SAC control center underground structure lower floor plan, drawing number 32-02-03, dated 1 February 1955 - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE

An assessment of the ability of Bartlett-Lewis type of rainfall models to reproduce drought statistics

NASA Astrophysics Data System (ADS)

Pham, M. T.; Vanhaute, W. J.; Vandenberghe, S.; De Baets, B.; Verhoest, N. E. C.

2013-12-01

Of all natural disasters, the economic and environmental consequences of droughts are among the highest because of their longevity and widespread spatial extent. Because of their extreme behaviour, studying droughts generally requires long time series of historical climate data. Rainfall is a very important variable for calculating drought statistics, for quantifying historical droughts or for assessing the impact on other hydrological (e.g. water stage in rivers) or agricultural (e.g. irrigation requirements) variables. Unfortunately, time series of historical observations are often too short for such assessments. To circumvent this, one may rely on the synthetic rainfall time series from stochastic point process rainfall models, such as Bartlett-Lewis models. The present study investigates whether drought statistics are preserved when simulating rainfall with Bartlett-Lewis models. Therefore, a 105 yr 10 min rainfall time series obtained at Uccle, Belgium is used as a test case. First, drought events were identified on the basis of the Effective Drought Index (EDI), and each event was characterized by two variables, i.e. drought duration (D) and drought severity (S). As both parameters are interdependent, a multivariate distribution function, which makes use of a copula, was fitted. Based on the copula, four types of drought return periods are calculated for observed as well as simulated droughts and are used to evaluate the ability of the rainfall models to simulate drought events with the appropriate characteristics. Overall, all Bartlett-Lewis model types studied fail to preserve extreme drought statistics, which is attributed to the model structure and to the model stationarity caused by maintaining the same parameter set during the whole simulation period.

A copula-based assessment of Bartlett-Lewis type of rainfall models for preserving drought statistics

NASA Astrophysics Data System (ADS)

Pham, M. T.; Vanhaute, W. J.; Vandenberghe, S.; De Baets, B.; Verhoest, N. E. C.

2013-06-01

Of all natural disasters, the economic and environmental consequences of droughts are among the highest because of their longevity and widespread spatial extent. Because of their extreme behaviour, studying droughts generally requires long time series of historical climate data. Rainfall is a very important variable for calculating drought statistics, for quantifying historical droughts or for assessing the impact on other hydrological (e.g. water stage in rivers) or agricultural (e.g. irrigation requirements) variables. Unfortunately, time series of historical observations are often too short for such assessments. To circumvent this, one may rely on the synthetic rainfall time series from stochastic point process rainfall models, such as Bartlett-Lewis models. The present study investigates whether drought statistics are preserved when simulating rainfall with Bartlett-Lewis models. Therefore, a 105 yr 10 min rainfall time series obtained at Uccle, Belgium is used as test case. First, drought events were identified on the basis of the Effective Drought Index (EDI), and each event was characterized by two variables, i.e. drought duration (D) and drought severity (S). As both parameters are interdependent, a multivariate distribution function, which makes use of a copula, was fitted. Based on the copula, four types of drought return periods are calculated for observed as well as simulated droughts and are used to evaluate the ability of the rainfall models to simulate drought events with the appropriate characteristics. Overall, all Bartlett-Lewis type of models studied fail in preserving extreme drought statistics, which is attributed to the model structure and to the model stationarity caused by maintaining the same parameter set during the whole simulation period.

L-selectin-carbohydrate interactions: relevant modifications of the Lewis x trisaccharide.

PubMed

Sanders, W J; Katsumoto, T R; Bertozzi, C R; Rosen, S D; Kiessling, L L

1996-11-26

Protein-carbohydrate interactions are known to mediate cell-cell recognition and adhesion events. Specifically, three carbohydrate binding proteins termed selectins (E-, P-, and L-selectin) have been shown to be essential for leukocyte rolling along the vascular endothelium, the first step in the recruitment of leukocytes from the blood into inflammatory sites or into secondary lymphoid organs. Although this phenomenon is well-established, little is known about the molecular-level interactions on which it depends. All three selectins recognize sulfated and sialylated derivatives of the Lewis x [Le(x):Gal beta 1-->4(Fuc alpha 1-->3)GlcNAc] and Lewis a [Le(a): Gal beta 1-->3(Fuc alpha 1-->4)GlcNAc] trisaccharide cores with affinities in the millimolar range, and it is believed that variants of these structures are the carbohydrate determinants of selectin recognition. Recently it was shown that the mucin GlyCAM-1, a secreted physiological ligand for L-selectin, is capped with sulfated derivatives of sialyl Lewis x [sLe(x): Sia alpha 2-->3Gal beta 1-->4(Fuc alpha 1-->3)GlcNAc] and that sulfation is required for the high-affinity interaction between GlyCAM-1 and L-selectin. To elucidate the important sites of sulfation on Le(x) with respect to L-selectin recognition, we have synthesized six sulfated Le(x) analogs and determined their abilities to block binding of a recombinant L-selectin-Ig chimera to immobilized GlyCAM-1. Our results suggest that 6-sulfo sLe(x) binds to L-selectin with higher affinity than does sLe(x) or 6'-sulfo sLe(x) and that sulfation of sLe(x) capping groups on GlyCAM-1 at the 6-position is important for L-selectin recognition.

Effects of different force fields on the structural character of α synuclein β-hairpin peptide (35-56) in aqueous environment.

PubMed

Kundu, Sangeeta

2018-02-01

The hallmark of Parkinson's disease (PD) is the intracellular protein aggregation forming Lewy Bodies (LB) and Lewy neuritis which comprise mostly of a protein, alpha synuclein (α-syn). Molecular dynamics (MD) simulation methods can augment experimental techniques to understand misfolding and aggregation pathways with atomistic resolution. The quality of MD simulations for proteins and peptides depends greatly on the accuracy of empirical force fields. The aim of this work is to investigate the effects of different force fields on the structural character of β hairpin fragment of α-syn (residues 35-56) peptide in aqueous solution. Six independent MD simulations are done in explicit solvent using, AMBER03, AMBER99SB, GROMOS96 43A1, GROMOS96 53A6, OPLS-AA, and CHARMM27 force fields with CMAP corrections. The performance of each force field is assessed from several structural parameters such as root mean square deviation (RMSD), root mean square fluctuation (RMSF), radius of gyration (Rg), solvent accessible surface area (SASA), formation of β-turn, the stability of folded β-hairpin structure, and the favourable conformations obtained for different force fields. In this study, CMAP correction of CHARMM27 force field is found to overestimate the helical conformation, while GROMOS96 53A6 is found to most successfully capture the conformational dynamics of α-syn β-hairpin fragment as elicited from NMR.

Temperature dependent CO2 behavior in microporous 1-D channels of a metal-organic framework with multiple interaction sites

PubMed Central

Kim, Dongwook; Park, Jaehun; Kim, Yung Sam; Lah, Myoung Soo

2017-01-01

The MOF with the encapsulated CO2 molecule shows that the CO2 molecule is ligated to the unsaturated Cu(II) sites in the cage using its Lewis basic oxygen atom via an angular η1-(OA) coordination mode and also interacts with Lewis basic nitrogen atoms of the tetrazole ligands using its Lewis acidic carbon atom. Temperature dependent structure analyses indicate the simultaneous weakening of both interactions as temperature increases. Infrared spectroscopy of the MOF confirmed that the CO2 interaction with the framework is temperature dependent. The strength of the interaction is correlated to the separation of the two bending peaks of the bound CO2 rather than the frequency shift of the asymmetric stretching peak from that of free CO2. The encapsulated CO2 in the cage is weakly interacting with the framework at around ambient temperatures and can have proper orientation for wiggling out of the cage through the narrow portals so that the reversible uptake can take place. On the other hand, the CO2 in the cage is restrained at a specific orientation at 195 K since it interacts with the framework strong enough using the multiple interaction sites so that adsorption process is slightly restricted and desorption process is almost clogged. PMID:28128298

Cyclotron Provides Neutron Therapy for Cancer Patients

NASA Image and Video Library

1978-01-21

A cancer patient undergoes treatment in the Neutron Therapy Treatment Facility, or Cylotron, at the National Aeronautics and Space Administration (NASA) Lewis Research Center. After World War II Lewis researchers became interested in nuclear energy for propulsion. The focused their efforts on thermodynamics and strength of materials after radiation. In 1950 an 80-person Nuclear Reactor Division was created, and a cyclotron was built behind the Materials and Structures Laboratory. An in-house nuclear school was established to train these researchers in their new field. NASA cancelled its entire nuclear program in January 1973, just as the cyclotron was about to resume operations after a major upgrade. In 1975 the Cleveland Clinic Foundation partnered with NASA Lewis to use the cyclotron for a new type of radiation treatment for cancer patients. The cyclotron split beryllium atoms which caused neutrons to be released. The neutrons were streamed directly at the patient’s tumor. The facility had a dual-beam system that could target the tumor both vertically and horizontally. Over the course of five years, the cyclotron was used to treat 1200 patients. It was found to be particularly effective on salivary gland, prostrate, and other tumors. It was not as successful with tumors of the central nervous system. The program was terminated in 1980 as the Clinic began concentrating on non-radiation treatments.

75 FR 42460 - Minor Boundary Revision at Lewis and Clark National Historical Park

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-21

... DEPARTMENT OF THE INTERIOR National Park Service Minor Boundary Revision at Lewis and Clark... Clark National Historical Park is modified to include an additional 106.74+/- acres of land identified..., Oregon, immediately adjacent to the southern boundary of the Sunset Beach portion of Lewis and Clark...

78 FR 59966 - Notice of Inventory Completion: Fort Lewis College, Durango, CO; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-30

... DEPARTMENT OF THE INTERIOR National Park Service [NPS-WASO-NAGPRA-13941; PPWOCRADN0-PCU00RP14.R50000] Notice of Inventory Completion: Fort Lewis College, Durango, CO; Correction AGENCY: National Park... objects. ADDRESSES: Dawn Mulhern, Department of Anthropology, Fort Lewis College, 1000 Rim Dr., Durango...

Unruly Woman: An Interview with Helen Lewis.

ERIC Educational Resources Information Center

Briscoe, Lori; Collins, Erica S.; Deal, Amanda; Hancock, Ron; McGraw, Kristyn; Lewis, Helen

2000-01-01

Overviews the career of Helen Lewis as sociologist, social activist, teacher, writer, researcher, and mentor. Helen Lewis discusses growing up in segregated Georgia, her unorthodox approach to education, her fight for social and economic equality, her instrumental role in the development of Appalachian Studies programs, and how social activism…

Plans and status of the NASA-Lewis Research Center wind energy project

NASA Technical Reports Server (NTRS)

Thomas, R.; Puthoff, R.; Savino, J.; Johnson, W.

1975-01-01

This report describes that portion of the national five-year wind energy program that is being managed by the NASA-Lewis Research Center for the ERDA. The Lewis Research Center's Wind Power Office, its organization and plans and status are briefly described. The three major elements of the wind energy project at Lewis are the experimental 100 kW wind-turbine generator; the first generation industry-built and user-operated wind turbine generators; and the supporting research and technology tasks which are each briefly described.

Historical perspectives - The role of the NASA Lewis Research Center in the national space nuclear power programs

NASA Technical Reports Server (NTRS)

Bloomfield, H. S.; Sovie, R. J.

1991-01-01

The history of the NASA Lewis Research Center's role in space nuclear power programs is reviewed. Lewis has provided leadership in research, development, and the advancement of space power and propulsion systems. Lewis' pioneering efforts in nuclear reactor technology, shielding, high temperature materials, fluid dynamics, heat transfer, mechanical and direct energy conversion, high-energy propellants, electric propulsion and high performance rocket fuels and nozzles have led to significant technical and management roles in many natural space nuclear power and propulsion programs.

Building new discrete supramolecular assemblies through the interaction of iso-tellurazole N-oxides with Lewis acids and bases.

PubMed

Ho, Peter C; Jenkins, Hilary A; Britten, James F; Vargas-Baca, Ignacio

2017-10-13

The supramolecular macrocycles spontaneously assembled by iso-tellurazole N-oxides are stable towards Lewis bases as strong as N-heterocyclic carbenes (NHC) but readily react with Lewis acids such as BR 3 (R = Ph, F). The electron acceptor ability of the tellurium atom is greatly enhanced in the resulting O-bonded adducts, which consequently enables binding to a variety of Lewis bases that includes acetonitrile, 4-dimethylaminopyridine, 4,4'-bipyridine, triphenyl phosphine, a N-heterocyclic carbene and a second molecule of iso-tellurazole N-oxide.

Historical perspectives: The role of the NASA Lewis Research Center in the national space nuclear power programs

NASA Technical Reports Server (NTRS)

Bloomfield, H. S.; Sovie, R. J.

1991-01-01

The history of the NASA Lewis Research Center's role in space nuclear power programs is reviewed. Lewis has provided leadership in research, development, and the advancement of space power and propulsion systems. Lewis' pioneering efforts in nuclear reactor technology, shielding, high temperature materials, fluid dynamics, heat transfer, mechanical and direct energy conversion, high-energy propellants, electric propulsion and high performance rocket fuels and nozzles have led to significant technical and management roles in many national space nuclear power and propulsion programs.

Differential Gene Expression in the Nucleus Accumbens and Frontal Cortex of Lewis and Fischer 344 Rats Relevant to Drug Addiction

PubMed Central

Higuera-Matas, A; Montoya, G. L; Coria, S.M; Miguéns, M; García-Lecumberri, C; Ambrosio, E

2011-01-01

Drug addiction results from the interplay between social and biological factors. Among these, genetic variables play a major role. The use of genetically related inbred rat strains that differ in their preference for drugs of abuse is one approach of great importance to explore genetic determinants. Lewis and Fischer 344 rats have been extensively studied and it has been shown that the Lewis strain is especially vulnerable to the addictive properties of several drugs when compared with the Fischer 344 strain. Here, we have used microarrays to analyze gene expression profiles in the frontal cortex and nucleus accumbens of Lewis and Fischer 344 rats. Our results show that only a very limited group of genes were differentially expressed in Lewis rats when compared with the Fischer 344 strain. The genes that were induced in the Lewis strain were related to oxygen transport, neurotransmitter processing and fatty acid metabolism. On the contrary genes that were repressed in Lewis rats were involved in physiological functions such as drug and proton transport, oligodendrocyte survival and lipid catabolism. These data might be useful for the identification of genes which could be potential markers of the vulnerability to the addictive properties of drugs of abuse. PMID:21886580

Using comprehension strategies with authentic text in a college chemistry course

NASA Astrophysics Data System (ADS)

Cain, Stephen Daniel

College science students learn important topics by reading textbooks, which contain dense technical prose. Comprehension strategies are known to increase learning from reading. One class of comprehension strategies, called elaboration strategies, is intended to link new information with prior knowledge. Elaboration strategies have an appeal in science courses where new information frequently depends on previously learned information. The purpose of this study was to determine the effectiveness of an elaboration strategy in an authentic college environment. General chemistry students read text about Lewis structures, figures drawn by chemists to depict molecules, while assigned to use either an elaboration strategy, namely elaborative interrogation, or another strategy, rereading, which served as a placebo control. Two texts of equal length were employed in this pretest-posttest experimental design. One was composed by the researcher. The other was an excerpt from a college textbook and contained a procedure for constructing Lewis structures. Students (N = 252) attending a large community college were randomly assigned to one of the two texts and assigned one of the two strategies. The elaborative interrogation strategy was implemented with instructions to answer why-questions posed throughout the reading. Answering why-questions has been hypothesized to activate prior knowledge of a topic, and thus to aid in cognitively connecting new material with prior knowledge. The rereading strategy was implemented with instructions to read text twice. The use of authentic text was one of only a few instances of applying elaborative interrogation with a textbook. In addition, previous studies have generally focused on the learning of facts contained in prose. The application of elaborative interrogation to procedural text has not been previously reported. Results indicated that the more effective strategy was undetermined when reading authentic text in this setting. However, prior knowledge level was identified as a statistically significant factor for learning from authentic text. That is, students with high prior knowledge learned more, regardless of assigned strategy. Another descriptive study was conducted with a separate student sample (N = 34). Previously reported Lewis structure research was replicated. The trend of difficulty for 50 structures in the earlier work was supported.

Reduction potentials of heterometallic manganese–oxido cubane complexes modulated by redox-inactive metals

PubMed Central

Tsui, Emily Y.; Agapie, Theodor

2013-01-01

Understanding the effect of redox-inactive metals on the properties of biological and heterogeneous water oxidation catalysts is important both fundamentally and for improvement of future catalyst designs. In this work, heterometallic manganese–oxido cubane clusters [MMn3O4] (M = Sr2+, Zn2+, Sc3+, Y3+) structurally relevant to the oxygen-evolving complex (OEC) of photosystem II were prepared and characterized. The reduction potentials of these clusters and other related mixed metal manganese–tetraoxido complexes are correlated with the Lewis acidity of the apical redox-inactive metal in a manner similar to a related series of heterometallic manganese–dioxido clusters. The redox potentials of the [SrMn3O4] and [CaMn3O4] clusters are close, which is consistent with the observation that the OEC is functional only with one of these two metals. Considering our previous studies of [MMn3O2] moieties, the present results with more structurally accurate models of the OEC ([MMn3O4]) suggest a general relationship between the reduction potentials of heterometallic oxido clusters and the Lewis acidities of incorporated cations that applies to diverse structural motifs. These findings support proposals that one function of calcium in the OEC is to modulate the reduction potential of the cluster to allow electron transfer. PMID:23744039

3. PHOTOCOPY, ARCHITECTURAL AND STRUCTURAL PLAN, ELEVATIONS, AND SECTION DRAWING ...

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

3. PHOTOCOPY, ARCHITECTURAL AND STRUCTURAL PLAN, ELEVATIONS, AND SECTION DRAWING FOR WATER TREATMENT PUMPING AND STORAGE BUILDING. - NIKE Missile Base SL-40, Water Treatment & Storage Building, Southern portion of launch area, southeast of Ready Building, Hecker, Monroe County, IL

Intralaminar nuclei of the thalamus in Lewy body diseases.

PubMed

Brooks, Daniel; Halliday, Glenda M

2009-02-16

Although the intralaminar thalamus is a target of alpha-synuclein pathology in Parkinson's disease, the degree of neuronal loss in Lewy body diseases has not been assessed. We have used unbiased stereological techniques to quantify neuronal loss in intralaminar thalamic nuclei concentrating alpha-synuclein pathology (the anterodorsal, cucullar, parataenial, paraventricular, central medial, central lateral and centre-median/parafascicular complex) in different clinical forms of Lewy body disease (Parkinson's disease with and without dementia, and dementia with Lewy bodies, N=21) compared with controls (N=5). Associations were performed in the Lewy body cases between intralaminar cell loss and the main diagnostic clinical (parkinsonism, dementia, fluctuation in consciousness, and visual hallucinations) and pathological (Braak stage of Parkinson's disease) features of these diseases, as well as between cell loss and the scaled severity of the alpha-synuclein deposition within the intralaminar thalamus. As expected, significant alpha-synuclein accumulation occurred in the intralaminar thalamus in the cases with Lewy body disease. Pathology concentrated anteriorly and in the central lateral and paraventricular nuclei was related to the Braak stage of Parkinson's disease, ageing, and the presence of dementia. Across all types of Lewy body cases there was substantial atrophy and neuronal loss in the central lateral, cucullar and parataenial nuclei, and neuronal loss without atrophy in the centre-median/parafascicular complex. Cases with visual hallucinations showed a greater degree of atrophy of the cucullar nucleus, possibly due to amygdala denervation. The significant degeneration demonstrated in the intralaminar thalamus is likely to contribute to the movement and cognitive dysfunction observed in Lewy body disorders.

Research and Technology 1996

NASA Technical Reports Server (NTRS)

1997-01-01

This report selectively summarizes the NASA Lewis Research Center's research and technology accomplishments for fiscal year 1996. It comprises 116 short articles submitted by the staff scientists and engineers. The report is organized into six major sections: Aeronautics, Aerospace Technology, Space Flight Systems, Engineering & Computational Support, Lewis Research Academy, and Technology Transfer. A table of contents, an author index, and a list of NASA Headquarters program offices have been included to assist the reader in finding articles of special interest. This report is not intended to be a comprehensive summary of all research and technology work done over the past fiscal year. Most of the work is reported in Lewis-published technical reports, journal articles, and presentations prepared by Lewis staff and contractors (for abstracts of these Lewis-authored reports, visit the Lewis Technical Report Server (LeTRS) on the World Wide Web-http:/letrs.lerc.nasa.gov/LeTRS/). In addition, university grants have enabled faculty members and graduate students to engage in sponsored research that is reported at technical meetings or in journal articles. For each article in this report, a Lewis contact person has been identified, and where possible, reference documents are listed so that additional information can be easily obtained. The diversity of topics attests to the breadth of research and technology being pursued and to the skill mix of the staff that makes it possible. For more information about Lewis' research, visit us on the World Wide Web (http://www.lerc.nasa.gov). Also, this document is available on the World Wide Web (http://www.lerc.nasa.gov/WWW/RT/).

High Level ab initio Predictions of the Energetics of mCO2•(H2O)n (n = 1-3, m = 1-12) Clusters

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

Thanthiriwatte, Sahan; Duke, Jessica R.; Jackson, Virgil E.

Electronic structure calculations at the correlated molecular orbital theory and density functional theory levels have been used to generate a reliable set of clustering energies for up to three water molecules in carbon dioxide clusters up to n = 12. The structures and energetics are dominated by Lewis acid-base interactions with hydrogen bonding interactions playing a lesser energetic role. The actual binding energies are somewhat larger than might be expected. The correlated molecular orbital MP2 method and density functional theory with the ωB97X exchange-correlation functional provide good results for the energetics of the clusters but the B3LYP and ωB97X-D functionalsmore » do not. Seven CO2 molecules form the first solvent shell about a single H2O with four CO2 molecules interacting with the H2O via Lewis acid-base interactions, two CO2 interacting with the H2O by hydrogen bonds, and the seventh CO2 completing the shell. The Lewis acid-base and weak hydrogen bond interactions between the water molecules and the CO2 molecules are strong enough to disrupt the trimer ring configuration for as few as seven CO2 molecules. Calculated 13C NMR chemical shifts for mCO2•(H2O)n show little change with respect to the number of H2O or CO2 molecules in the cluster. The O-H stretching frequencies do exhibit shifts that can provide information about the interactions between water and CO2 molecules.« less

Highly Sensitive and Selective Uranium Detection in Natural Water Systems Using a Luminescent Mesoporous Metal-Organic Framework Equipped with Abundant Lewis Basic Sites: A Combined Batch, X-ray Absorption Spectroscopy, and First Principles Simulation Investigation.

PubMed

Liu, Wei; Dai, Xing; Bai, Zhuanling; Wang, Yanlong; Yang, Zaixing; Zhang, Linjuan; Xu, Lin; Chen, Lanhua; Li, Yuxiang; Gui, Daxiang; Diwu, Juan; Wang, Jianqiang; Zhou, Ruhong; Chai, Zhifang; Wang, Shuao

2017-04-04

Uranium is not only a strategic resource for the nuclear industry but also a global contaminant with high toxicity. Although several strategies have been established for detecting uranyl ions in water, searching for new uranium sensor material with great sensitivity, selectivity, and stability remains a challenge. We introduce here a hydrolytically stable mesoporous terbium(III)-based MOF material compound 1, whose channels are as large as 27 Å × 23 Å and are equipped with abundant exposed Lewis basic sites, the luminescence intensity of which can be efficiently and selectively quenched by uranyl ions. The detection limit in deionized water reaches 0.9 μg/L, far below the maximum contamination standard of 30 μg/L in drinking water defined by the United States Environmental Protection Agency, making compound 1 currently the only MOF material that can achieve this goal. More importantly, this material exhibits great capability in detecting uranyl ions in natural water systems such as lake water and seawater with pH being adjusted to 4, where huge excesses of competing ions are present. The uranyl detection limits in Dushu Lake water and in seawater were calculated to be 14.0 and 3.5 μg/L, respectively. This great detection capability originates from the selective binding of uranyl ions onto the Lewis basic sites of the MOF material, as demonstrated by synchrotron radiation extended X-ray adsorption fine structure, X-ray adsorption near edge structure, and first principles calculations, further leading to an effective energy transfer between the uranyl ions and the MOF skeleton.

Probabilistic structural analysis methods of hot engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Hopkins, D. A.

1989-01-01

Development of probabilistic structural analysis methods for hot engine structures at Lewis Research Center is presented. Three elements of the research program are: (1) composite load spectra methodology; (2) probabilistic structural analysis methodology; and (3) probabilistic structural analysis application. Recent progress includes: (1) quantification of the effects of uncertainties for several variables on high pressure fuel turbopump (HPFT) turbine blade temperature, pressure, and torque of the space shuttle main engine (SSME); (2) the evaluation of the cumulative distribution function for various structural response variables based on assumed uncertainties in primitive structural variables; and (3) evaluation of the failure probability. Collectively, the results demonstrate that the structural durability of hot engine structural components can be effectively evaluated in a formal probabilistic/reliability framework.

Lewis Structures Technology, 1988. Volume 3: Structural Integrity Fatigue and Fracture Wind Turbines HOST

NASA Technical Reports Server (NTRS)

1988-01-01

The charter of the Structures Division is to perform and disseminate results of research conducted in support of aerospace engine structures. These results have a wide range of applicability to practioners of structural engineering mechanics beyond the aerospace arena. The specific purpose of the symposium was to familiarize the engineering structures community with the depth and range of research performed by the division and its academic and industrial partners. Sessions covered vibration control, fracture mechanics, ceramic component reliability, parallel computing, nondestructive evaluation, constitutive models and experimental capabilities, dynamic systems, fatigue and damage, wind turbines, hot section technology (HOST), aeroelasticity, structural mechanics codes, computational methods for dynamics, structural optimization, and applications of structural dynamics, and structural mechanics computer codes.

Computational structural mechanics for engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1989-01-01

The computational structural mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures. It is structured to mainly supplement, complement, and whenever possible replace, costly experimental efforts which are unavoidable during engineering research and development programs. Specific objectives include: investigate unique advantages of parallel and multiprocesses for: reformulating/solving structural mechanics and formulating/solving multidisciplinary mechanics and develop integrated structural system computational simulators for: predicting structural performances, evaluating newly developed methods, and for identifying and prioritizing improved/missing methods needed. Herein the CSM program is summarized with emphasis on the Engine Structures Computational Simulator (ESCS). Typical results obtained using ESCS are described to illustrate its versatility.

Assessing College Students' Understanding of Acid Base Chemistry Concepts

ERIC Educational Resources Information Center

Wan, Yanjun Jean

2014-01-01

Typically most college curricula include three acid base models: Arrhenius', Bronsted-Lowry's, and Lewis'. Although Lewis' acid base model is generally thought to be the most sophisticated among these three models, and can be further applied in reaction mechanisms, most general chemistry curricula either do not include Lewis' acid base model, or…

Generalized Spencer-Lewis equation

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

Filippone, W.L.

The Spencer-Lewis equation, which describes electron transport in homogeneous media when continuous slowing down theory is valid, is derived from the Boltzmann equation. Also derived is a time-dependent generalized Spencer-Lewis equation valid for inhomogeneous media. An independent verification of this last equation is obtained for the one-dimensional case using particle balance considerations.

Quantification of Lewis's Woodpecker habitat using Forest Inventory and Analysis data

Treesearch

Chris Witt

2009-01-01

The Utah Department of Natural Resources' Division of Wildlife Resources (UDWR) placed Lewis's Woodpecker (Melanerpes lewis) on their Sensitive Species Tier II list due to declining populations and suspected local extirpations throughout the state. It is thought that the decline in burned coniferous forest has reduced the amount of suitable...

Impairments of Speech Fluency in Lewy Body Spectrum Disorder

ERIC Educational Resources Information Center

Ash, Sharon; McMillan, Corey; Gross, Rachel G.; Cook, Philip; Gunawardena, Delani; Morgan, Brianna; Boller, Ashley; Siderowf, Andrew; Grossman, Murray

2012-01-01

Few studies have examined connected speech in demented and non-demented patients with Parkinson's disease (PD). We assessed the speech production of 35 patients with Lewy body spectrum disorder (LBSD), including non-demented PD patients, patients with PD dementia (PDD), and patients with dementia with Lewy bodies (DLB), in a semi-structured…

Discovering Lewis and Clark

ERIC Educational Resources Information Center

Olsen, Ken

2006-01-01

Writer and historian Bernard DeVoto observed more than 50 years ago that a dismaying amount of American history has been written without regards to the Indians. Such disregard is glaring in many mainstream stories of Meriwether Lewis and William Clark. Lewis and Clark began preparing for their historic journey in 1803 and officially launched the…

Nest-site selection and nest survival of Lewis's woodpecker in aspen riparian woodlands

Treesearch

Karen R. Newlon; Victoria A. Saab

2011-01-01

Riparian woodlands of aspen (Populus tremuloides) provide valuable breeding habitat for several cavity-nesting birds. Although anecdotal information for this habitat is available for Lewis's Woodpecker (Melanerpes lewis), no study has previously examined the importance of aspen woodlands to this species' breeding biology. From 2002 to 2004, we monitored 76...

Understanding the Role of Culture and Communication in Implementing Planned Organizational Change: The Case of Compstat in Police Organizations

ERIC Educational Resources Information Center

Yuksel, Yusuf

2013-01-01

Despite the popularity of planned change efforts, the failure rates of implementation are as high as 50 to 70 percent (Lewis & Seibold, 1998). While these efforts are affected by technical issues, the organizations' approach to change, structure, technological capabilities, and organizational culture and communication practices are…

Development of the Bonding Representations Inventory to Identify Student Misconceptions about Covalent and Ionic Bonding Representations

ERIC Educational Resources Information Center

Luxford, Cynthia J.; Bretz, Stacey Lowery

2014-01-01

Teachers use multiple representations to communicate the concepts of bonding, including Lewis structures, formulas, space-filling models, and 3D manipulatives. As students learn to interpret these multiple representations, they may develop misconceptions that can create problems in further learning of chemistry. Interviews were conducted with 28…

Fire and fire-suppression impacts on forest-soil carbon [Chapter 13

Treesearch

Deborah Page-Dumroese; Martin F. Jurgensen; Alan E. Harvey

2003-01-01

The potential of forest soils to sequester carbon (C) depends on many biotic and abiotic variables, such as: forest type, stand age and structure, root activity and turnover, temperature and moisture conditions, and soil physical, chemical, and biological properties (Birdsey and Lewis, Chapter 2; Johnson and Kern, Chapter 4; Pregitzer, Chapter 6; Morris and Paul,...

Bond Order and Chemical Properties of BF, CO, and N[subscript 2

ERIC Educational Resources Information Center

Martinie, Ryan J.; Bultema, Jarred J.; Vander Wal, Mark N.; Burkhart, Brandon J.; Vander Griend, Douglas A.; DeKock, Roger L.

2011-01-01

The traditional chemical approaches, Lewis electron dot structures and molecular orbital theory, predict the relative bond orders of boron monofluoride, carbon monoxide, and dinitrogen to be BF less than CO less than N[subscript 2]. This is quantified by quantum mechanical, theoretical studies that show the bond orders to be approximately 1.4,…

YF-12 Experiments Symposium, Volume 1

NASA Technical Reports Server (NTRS)

1978-01-01

Papers presented by personnel from the Dryden Flight Research Center, the Lewis Research Center, and the Ames Research Center are presented. Topics cover propulsion system performance, inlet time varying distortion, structures, aircraft controls, propulsion controls, and aerodynamics. The reports were based on analytical studies, laboratory experiments, wind tunnel tests, and extensive flight research with two YF-12 airplanes.

Lewis Research Center studies of multiple large wind turbine generators on a utility network

NASA Technical Reports Server (NTRS)

Gilbert, L. J.; Triezenberg, D. M.

1979-01-01

A NASA-Lewis program to study the anticipated performance of a wind turbine generator farm on an electric utility network is surveyed. The paper describes the approach of the Lewis Wind Energy Project Office to developing analysis capabilities in the area of wind turbine generator-utility network computer simulations. Attention is given to areas such as, the Lewis Purdue hybrid simulation, an independent stability study, DOE multiunit plant study, and the WEST simulator. Also covered are the Lewis mod-2 simulation including analog simulation of a two wind turbine system and comparison with Boeing simulation results, and gust response of a two machine model. Finally future work to be done is noted and it is concluded that the study shows little interaction between the generators and between the generators and the bus.

Solid frustrated-Lewis-pair catalysts constructed by regulations on surface defects of porous nanorods of CeO2

PubMed Central

Zhang, Sai; Huang, Zheng-Qing; Ma, Yuanyuan; Gao, Wei; Li, Jing; Cao, Fangxian; Li, Lin; Chang, Chun-Ran; Qu, Yongquan

2017-01-01

Identification on catalytic sites of heterogeneous catalysts at atomic level is important to understand catalytic mechanism. Surface engineering on defects of metal oxides can construct new active sites and regulate catalytic activity and selectivity. Here we outline the strategy by controlling surface defects of nanoceria to create the solid frustrated Lewis pair (FLP) metal oxide for efficient hydrogenation of alkenes and alkynes. Porous nanorods of ceria (PN-CeO2) with a high concentration of surface defects construct new Lewis acidic sites by two adjacent surface Ce3+. The neighbouring surface lattice oxygen as Lewis base and constructed Lewis acid create solid FLP site due to the rigid lattice of ceria, which can easily dissociate H–H bond with low activation energy of 0.17 eV. PMID:28516952

Cerebral Microbleeds in Patients with Dementia with Lewy Bodies and Parkinson Disease Dementia.

PubMed

Kim, S W; Chung, S J; Oh, Y-S; Yoon, J H; Sunwoo, M K; Hong, J Y; Kim, J-S; Lee, P H

2015-09-01

The burden of amyloid β is greater in patients with dementia with Lewy bodies than in those with Parkinson disease dementia, and an increased amyloid β load is closely related to a higher incidence of cerebral microbleeds. Here, we investigated the prevalence and topography of cerebral microbleeds in patients with dementia with Lewy bodies and those with Parkinson disease dementia to examine whether cerebral microbleeds are more prevalent in patients with dementia with Lewy bodies than in those with Parkinson disease dementia. The study population consisted of 42 patients with dementia with Lewy bodies, 88 patients with Parkinson disease dementia, and 35 controls who underwent brain MR imaging with gradient recalled-echo. Cerebral microbleeds were classified as deep, lobar, or infratentorial. The frequency of cerebral microbleeds was significantly greater in patients with dementia with Lewy bodies (45.2%) than in those with Parkinson disease dementia (26.1%) or in healthy controls (17.1%; P = .017). Lobar cerebral microbleeds were observed more frequently in the dementia with Lewy bodies group (40.5%) than in the Parkinson disease dementia (17%; P = .004) or healthy control (8.6%; P = .001) group, whereas the frequencies of deep and infratentorial cerebral microbleeds did not differ among the 3 groups. Logistic regression analyses revealed that, compared with the healthy control group, the dementia with Lewy bodies group was significantly associated with the presence of lobar cerebral microbleeds after adjusting for age, sex, nonlobar cerebral microbleeds, white matter hyperintensities, and other vascular risk factors (odds ratio, 4.39 [95% CI, 1.27-15.25]). However, compared with the healthy control group, the Parkinson disease dementia group was not significantly associated with lobar cerebral microbleeds. This study showed that patients with dementia with Lewy bodies had a greater burden of cerebral microbleeds and exhibited a lobar predominance of cerebral microbleeds than did patients with Parkinson disease dementia. © 2015 by American Journal of Neuroradiology.

Clinical and imaging correlates of amyloid deposition in dementia with Lewy bodies.

PubMed

Donaghy, Paul C; Firbank, Michael J; Thomas, Alan J; Lloyd, Jim; Petrides, George; Barnett, Nicola; Olsen, Kirsty; O'Brien, John T

2018-04-19

Amyloid deposition is common in dementia with Lewy bodies, but its pathophysiological significance is unclear. The objective of this study was to investigate the relationship between amyloid deposition and clinical profile, gray matter volume, and brain perfusion in dementia with Lewy bodies. Dementia with Lewy bodies (n = 37), Alzheimer's disease (n = 20), and controls (n = 20) underwent a thorough clinical assessment, 3T MRI, and early- and late-phase 18 F-Florbetapir PET-CT to assess cortical perfusion and amyloid deposition, respectively. Amyloid scans were visually categorized as positive or negative. Image analysis was carried out using statistical parametric mapping (SPM) 8. There were no significant differences between amyloid-positive and amyloid-negative dementia with Lewy bodies cases in age (P = .78), overall cognitive impairment (P = .83), level of functional impairment (P = .80), or any other clinical or cognitive scale. There were also no significant differences in hippocampal or gray matter volumes. However, amyloid-positive dementia with Lewy bodies cases had lower medial temporal lobe perfusion (P = .03) than amyloid-negative cases, although a combination of medial temporal lobe perfusion, hippocampal volume, and cognitive measures was unable to accurately predict amyloid status in dementia with Lewy bodies. Amyloid deposition was not associated with differences in clinical or neuropsychological profiles in dementia with Lewy bodies, but was associated with imaging evidence of medial temporal lobe dysfunction. The presence of amyloid in dementia with Lewy bodies cannot be identified on the basis of clinical and other imaging features and will require direct assessment via PET imaging or CSF. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

R2R - software to speed the depiction of aesthetic consensus RNA secondary structures

PubMed Central

2011-01-01

Background With continuing identification of novel structured noncoding RNAs, there is an increasing need to create schematic diagrams showing the consensus features of these molecules. RNA structural diagrams are typically made either with general-purpose drawing programs like Adobe Illustrator, or with automated or interactive programs specific to RNA. Unfortunately, the use of applications like Illustrator is extremely time consuming, while existing RNA-specific programs produce figures that are useful, but usually not of the same aesthetic quality as those produced at great cost in Illustrator. Additionally, most existing RNA-specific applications are designed for drawing single RNA molecules, not consensus diagrams. Results We created R2R, a computer program that facilitates the generation of aesthetic and readable drawings of RNA consensus diagrams in a fraction of the time required with general-purpose drawing programs. Since the inference of a consensus RNA structure typically requires a multiple-sequence alignment, the R2R user annotates the alignment with commands directing the layout and annotation of the RNA. R2R creates SVG or PDF output that can be imported into Adobe Illustrator, Inkscape or CorelDRAW. R2R can be used to create consensus sequence and secondary structure models for novel RNA structures or to revise models when new representatives for known RNA classes become available. Although R2R does not currently have a graphical user interface, it has proven useful in our efforts to create 100 schematic models of distinct noncoding RNA classes. Conclusions R2R makes it possible to obtain high-quality drawings of the consensus sequence and structural models of many diverse RNA structures with a more practical amount of effort. R2R software is available at http://breaker.research.yale.edu/R2R and as an Additional file. PMID:21205310

Stationary and oscillatory convection of binary fluids in a porous medium.

PubMed

Augustin, M; Umla, R; Huke, B; Lücke, M

2010-11-01

We investigate numerically stationary convection and traveling wave structures of binary fluid mixtures with negative separation ratio in the Rayleigh-Bénard system filled with a porous medium. The bifurcation behavior of these roll structures is elucidated as well as the properties of the velocity, temperature, and concentration fields. Moreover, we discuss lateral averaged currents of temperature and concentration. Finally, we investigate the influence of the Lewis number, of the separation ratio, and of the normalized porosity on the bifurcation branches.

Structure, bonding, and reactivity of reactant complexes and key intermediates.

PubMed

Soriano, Elena; Marco-Contelles, José

2011-01-01

Complexes of Pt and Au (gold(III) and cationic gold(I)) have shown an exceptional ability to promote a variety of organic transformations of unsaturated precursors due to their peculiar Lewis acid properties: the alkynophilic character of these soft metals and the π-acid activation of unsaturated groups promotes the intra- or intermolecular attack of a nucleophile. In this chapter we summarize the computational data reported on the structure, bonding, and reactivity of the reactant π-complexes and also on the key intermediate species.

Probabilistic structural analysis to quantify uncertainties associated with turbopump blades

NASA Technical Reports Server (NTRS)

Nagpal, Vinod K.; Rubinstein, Robert; Chamis, Christos C.

1988-01-01

A probabilistic study of turbopump blades has been in progress at NASA Lewis Research Center for over the last two years. The objectives of this study are to evaluate the effects of uncertainties in geometry and material properties on the structural response of the turbopump blades to evaluate the tolerance limits on the design. A methodology based on probabilistic approach was developed to quantify the effects of the random uncertainties. The results indicate that only the variations in geometry have significant effects.

78 FR 36591 - David M. Lewis, D.M.D., Dismissal of Proceeding

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-18

... DEPARTMENT OF JUSTICE Drug Enforcement Administration David M. Lewis, D.M.D., Dismissal of Proceeding On December 5, 2012, the Deputy Assistant Administrator, Office of Diversion Control, Drug Enforcement Administration (DEA), issued an Order to Show Cause to David M. Lewis, D.M.D. (Registrant), of Sacramento, California. The Show Cause Order...

The First Confirmed Case of Down Syndrome with Dementia with Lewy Bodies

ERIC Educational Resources Information Center

Prasher, V. P.; Airuehia, E.; Carey, M.

2010-01-01

Dementia with Lewy bodies (DLB) is the second commonest cause of dementia in the general population. Several researches have established an association between Down syndrome (DS) and Alzheimer's disease. Very few studies have however showed such an association between dementia with Lewy bodies and Down syndrome. The occurrence of DLB in persons…

76 FR 77008 - Notice of Administrative Boundary Change for Bureau of Land Management Offices in Montana To...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-09

... Lewis and Clark County AGENCY: Bureau of Land Management, Interior. ACTION: Notice. SUMMARY: The... realign Lewis and Clark County, currently a split county between the two offices, to the Western Montana... Broadwater, Deer Lodge, Gallatin, Jefferson, Lewis and Clark, Park, Silver Bow and the northern portion of...

Narnian Virtues: C.S. Lewis as Character Educator

ERIC Educational Resources Information Center

Pike, Mark; Lickona, Thomas; Nesfield, Victoria

2015-01-01

This article argues that C.S. Lewis is a highly relevant but largely neglected character educator for 21st century schools characterized by diversity. We make the case for the objective reality of Lewis's Tao, the moral law recognized in the moral precepts of a wide range of cultures and traditions. We show why these universal precepts are…

Adele Parot: Beacon of the Dioclesian Lewis School of Gymnastic Expression in the American West.

ERIC Educational Resources Information Center

Barney, Robert Knight

In the late 1800's, Dioclesian Lewis developed and introduced into the schools his new concept of physical education. Dr. Lewis thought in terms of preventing illness and maintaining bodily strength and health through physical fitness. His "new gymnastics" were based on programs of exercise movements. Employing light equipment suitable…

Sentence Processing in Lewy Body Spectrum Disorder: The Role of Working Memory

ERIC Educational Resources Information Center

Gross, Rachel G.; McMillan, Corey T.; Chandrasekaran, Keerthi; Dreyfuss, Michael; Ash, Sharon; Avants, Brian; Cook, Philip; Moore, Peachie; Libon, David J.; Siderowf, Andrew; Grossman, Murray

2012-01-01

Prior work has related sentence processing to executive deficits in non-demented patients with Parkinson's disease (PD). We extended this investigation to patients with dementia with Lewy bodies (DLB) and PD dementia (PDD) by examining grammatical and working memory components of sentence processing in the full range of patients with Lewy body…

78 FR 22940 - Notice of Intent To Rule on Request To Lease Airport Property for Non-Aeronautical Purpose at the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-17

... To Lease Airport Property for Non-Aeronautical Purpose at the Bradford Regional Airport, Lewis Run... lease of land for non-aeronautical purpose at the Bradford Regional Airport, Lewis Run, Pennsylvania... Frungillo, Airport Director, Bradford Regional Airport, 212 Airport Drive, Suite E, Lewis Run, Pennsylvania...

Structure and blood compatibility of highly oriented PLA/MWNTs composites produced by solid hot drawing.

PubMed

Li, Zhengqiu; Zhao, Xiaowen; Ye, Lin; Coates, Phil; Caton-Rose, Fin; Martyn, Michasel

2014-03-01

Highly oriented poly(lactic acid) (PLA)/multi-walled carbon nanotubes (MWNTs) composites were fabricated through solid hot drawing technology in an effort to improve the mechanical properties and blood biocompatibility of PLA as blood-contacting medical devices. It was found that proper MWNTs content and drawing orientation can improve the tensile strength and modulus of PLA dramatically. With the increase in draw ratio, the cold crystallization peak became smaller, and the glass transition and the melting peak of PLA moved to high temperature, while the crystallinity increased, and the grain size decreased, indicating the stress-induced crystallization of PLA during drawing. MWNTs showed a nucleation effect on PLA, leading to the rise in the melting temperature, increase in crystallinity and reduction of spherulite size for the composites. Moreover, the intensity of (002) diffraction of MWNTs increased with draw ratio, indicating that MWNTs were preferentially aligned and oriented during drawing. Microstructure observation demonstrated that PLA matrix had an ordered fibrillar bundle structure, and MWNTs in the composite tended to align parallel to the drawing direction. In addition, the dispersion of MWNTs in PLA was also improved by orientation. Introduction of MWNTs and drawing orientation could significantly enhance the blood compatibility of PLA by prolonging kinetic clotting time, reducing hemolysis ratio and platelet activation.

Metabolic network visualization eliminating node redundance and preserving metabolic pathways

PubMed Central

Bourqui, Romain; Cottret, Ludovic; Lacroix, Vincent; Auber, David; Mary, Patrick; Sagot, Marie-France; Jourdan, Fabien

2007-01-01

Background The tools that are available to draw and to manipulate the representations of metabolism are usually restricted to metabolic pathways. This limitation becomes problematic when studying processes that span several pathways. The various attempts that have been made to draw genome-scale metabolic networks are confronted with two shortcomings: 1- they do not use contextual information which leads to dense, hard to interpret drawings, 2- they impose to fit to very constrained standards, which implies, in particular, duplicating nodes making topological analysis considerably more difficult. Results We propose a method, called MetaViz, which enables to draw a genome-scale metabolic network and that also takes into account its structuration into pathways. This method consists in two steps: a clustering step which addresses the pathway overlapping problem and a drawing step which consists in drawing the clustered graph and each cluster. Conclusion The method we propose is original and addresses new drawing issues arising from the no-duplication constraint. We do not propose a single drawing but rather several alternative ways of presenting metabolism depending on the pathway on which one wishes to focus. We believe that this provides a valuable tool to explore the pathway structure of metabolism. PMID:17608928

A Biography of Distinguished Scientist Gilbert Newton Lewis (by Edward S. Lewis)

NASA Astrophysics Data System (ADS)

Harris, Reviewed By Harold H.

1999-11-01

The Edward Mellen Press: Lewiston, NY, 1998. 114 pp + index. ISBN 0-7734-8284-9. $69.95. There may not be a surname better known to students of chemistry than Lewis, from the Lewis electron-dot diagrams and the Lewis theory of acids and bases. More advanced students may know of the groundbreaking textbook Thermodynamics, by Lewis and Randall. Yet few Americans know much about this remarkable U.S.-born scholar, whose contributions equal those of the greatest scientists. He is a chemist-educator of whom we should be as proud and as well informed as we are of Linus Pauling, who was part of the westward movement of science in this country that G. N. Lewis began, or of the recently deceased Glenn Seaborg, who was one of the many students of Lewis who achieved renown. Gilbert N. Lewis was born in Weymouth, Massachusetts, in 1875, but his family moved to near Lincoln, Nebraska, in 1884. He spent two years at the University of Nebraska, but then moved to Harvard when his father became an executive at Merchants Trust Company in Boston. Young Lewis (then only 17) was also said to have been disappointed with the quality of education in Nebraska, and this may have been part of the impetus for the family's move east. After earning his baccalaureate at Harvard, he taught for a year at Phillips Andover Academy before returning to Harvard to study for his doctorate, which he completed 100 years ago, in 1899, under T. W. Richards. Lewis's doctoral work was on the thermodynamics of zinc and cadmium amalgams. At that time, physical chemistry was only beginning to achieve recognition as a branch of science, and its boundaries were ill defined. Edward Lewis quotes his father as often saying, "Physical chemistry is anything interesting." Like many chemists of his time, Lewis went to Europe to complete his preparation for a career; he was in the laboratories of Ostwald in Leipzig and Nernst in Göttingen in 1900-1901. On his return to the United States, he was an instructor at Harvard until 1904, when he accepted a position that would not be considered a shrewd career move: Superintendent of Weights and Measures in Manila, Philippines! He was there only one year, but it was apparently a productive time, both in a minimally equipped laboratory and with the possible nascence of some of his ideas about bonding. In 1905, Lewis accepted a staff position at MIT, under A. A. Noyes, where he remained until 1912. At MIT, he continued his experimental work on thermodynamic systems and the development of modern thermodynamics, following the lead of J. W. Gibbs, whose work was being largely ignored by other chemists. As Noyes moved increasingly into administrative responsibilities, Lewis took over more and more of the supervision of scientific work in the laboratory. It was the capable job that he did for Noyes that led to his being offered a Professorship and Chair of the College of Chemistry at the University of California, Berkeley. The same spirit of adventure that took Lewis to Manila may be what led to his moving to scientifically backward California. In 1912, there was no serious science going on the Left Coast, and Berkeley was isolated from the nearest civilization (Chicago) by days of travel. Lewis initiated the expansion of great science westward, not only to Berkeley, but also to Caltech (in those days Throop Institute), UCLA, and Stanford. By dint of his contributions to thermodynamics and bonding theory (suggesting that electrons bond in pairs, long before there was quantum mechanical justification for such a strange idea), and his organizational and leadership talents, he turned the Berkeley Chemistry Department from a nonentity into one of the finest anywhere. Later in his career, he contributed to the understanding of the role of isotopes in chemistry and physics. This biography includes a useful listing of Lewis's 168 scientific publications. In an age when many renowned scientists have multiples of this number, it is perhaps good to be reminded that quality counts, too. His story deserves much greater recognition (he should have won a Nobel of his own) and I am happy to see the appearance of this biography. On the other hand, it is unfortunate that a better book did not result from the author's heartfelt best intentions. Edward Lewis covers his father's career in barely over 100 pages of uninspiring prose. Ten percent of that is wasted in printing letters from famous scientists, many of them Lewis's students and Nobel laureates, endorsing the greatness of their colleague. Even the title of the book is off-putting: if the subject of a biography is "distinguished", it should not be necessary to make the claim in the title. I also wonder at the price of this slim volume. In the more than fifty years since Lewis died in 1946, nearly all of his students have also died. Even his chemist son had difficulty in finding contemporaries of his father who could provide recollections and original material for the history. The best of his sources is this Journal, which published in January-March issues of 1984 the proceedings of a symposium on the life and work of G. N. Lewis that had been held March 30-31, 1982, in Las Vegas. I recommend those papers, by Derek Davenport, Richard Lewis (G. N.'s other chemist son), John Servos, Melvin Calvin, Glenn Seaborg, Gerald Branch, Leo Brewer, Kenneth Pitzer, Jacob Bigeleisen, Anthony Stranges, Linus Pauling, William Jensen, and Michael Kasha.

Linking heterometallic rings for quantum information processing and amusement.

PubMed

Timco, Grigore A; Faust, Thomas B; Tuna, Floriana; Winpenny, Richard E P

2011-06-01

Linking polymetallic cages can be a method for creating new structures and new properties. In this tutorial review we use heterometallic anti-ferromagnetically coupled rings (AF-rings) as exemplars for three approaches that can be used to link cage compounds. The first of three routes involves an ion-pair interaction supported by hydrogen-bonding interactions, which allows the synthesis of hybrid rotaxanes among other materials. The second route involves functionalising the exterior of the AF-ring so that it will act as a Lewis base; complexes involving coordination of pyridine to bridging monometallic and dimetallic fragments are discussed. The third route involves creating a vacancy on one site of the AF-ring, and then using the ring as a Lewis acid. Di-imine ligands can then be used to link the AF-rings into dimers. A brief discussion of the physical properties of these systems is also included.

A Novel Type of Macrothrombocytopenia Associated with a Defect in α2,3-Sialylation

PubMed Central

Jones, Claire; Denecke, Jonas; Sträter, Ronald; Stölting, Torsten; Schunicht, Yvonne; Zeuschner, Dagmar; Klumperman, Judith; Lefeber, Dirk J.; Spelten, Oliver; Zarbock, Alexander; Kelm, Sørge; Strenge, Karen; Haslam, Stuart M.; Lühn, Kerstin; Stahl, Dorothea; Gentile, Luca; Schreiter, Thomas; Hilgard, Philip; Beck-Sickinger, Annette G.; Marquardt, Thorsten; Wild, Martin K.

2011-01-01

We describe a novel type of human thrombocytopenia characterized by the appearance of giant platelets and variable neutropenia. Searching for the molecular defect, we found that neutrophils had strongly reduced sialyl-Lewis X and increased Lewis X surface expression, pointing to a deficiency in sialylation. We show that the glycosylation defect is restricted to α2,3-sialylation and can be detected in platelets, neutrophils, and monocytes. Platelets exhibited a distorted structure of the open canalicular system, indicating defective platelet generation. Importantly, patient platelets, but not normal platelets, bound to the asialoglycoprotein receptor (ASGP-R), a liver cell-surface protein that removes desialylated thrombocytes from the circulation in mice. Taken together, this is the first type of human thrombocytopenia in which a specific defect of α2,3-sialylation and an induction of platelet binding to the liver ASGP-R could be detected. PMID:21864493

Gear noise, vibration, and diagnostic studies at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Zakrajsek, James J.; Oswald, Fred B.; Townsend, Dennis P.; Coy, John J.

1990-01-01

The NASA Lewis Research Center and the U.S. Army Aviation Systems Command are involved in a joint research program to advance the technology of rotorcraft transmissions. This program consists of analytical as well as experimental efforts to achieve the overall goals of reducing weight, noise, and vibration, while increasing life and reliability. Recent analytical activities are highlighted in the areas of gear noise, vibration, and diagnostics performed in-house and through NASA and U.S. Army sponsored grants and contracts. These activities include studies of gear tooth profiles to reduce transmission error and vibration as well as gear housing and rotordynamic modeling to reduce structural vibration transmission and noise radiation, and basic research into current gear failure diagnostic methodologies. Results of these activities are presented along with an overview of near term research plans in the gear noise, vibration, and diagnostics area.

Polymer, metal and ceramic matrix composites for advanced aircraft engine applications

NASA Technical Reports Server (NTRS)

Mcdanels, D. L.; Serafini, T. T.; Dicarlo, J. A.

1985-01-01

Advanced aircraft engine research within NASA Lewis is being focused on propulsion systems for subsonic, supersonic, and hypersonic aircraft. Each of these flight regimes requires different types of engines, but all require advanced materials to meet their goals of performance, thrust-to-weight ratio, and fuel efficiency. The high strength/weight and stiffness/weight properties of resin, metal, and ceramic matrix composites will play an increasingly key role in meeting these performance requirements. At NASA Lewis, research is ongoing to apply graphite/polyimide composites to engine components and to develop polymer matrices with higher operating temperature capabilities. Metal matrix composites, using magnesium, aluminum, titanium, and superalloy matrices, are being developed for application to static and rotating engine components, as well as for space applications, over a broad temperature range. Ceramic matrix composites are also being examined to increase the toughness and reliability of ceramics for application to high-temperature engine structures and components.

Physics and Process Modeling (PPM) and Other Propulsion R and T. Volume 1; Materials Processing, Characterization, and Modeling; Lifting Models

NASA Technical Reports Server (NTRS)

1997-01-01

This CP contains the extended abstracts and presentation figures of 36 papers presented at the PPM and Other Propulsion R&T Conference. The focus of the research described in these presentations is on materials and structures technologies that are parts of the various projects within the NASA Aeronautics Propulsion Systems Research and Technology Base Program. These projects include Physics and Process Modeling; Smart, Green Engine; Fast, Quiet Engine; High Temperature Engine Materials Program; and Hybrid Hyperspeed Propulsion. Also presented were research results from the Rotorcraft Systems Program and work supported by the NASA Lewis Director's Discretionary Fund. Authors from NASA Lewis Research Center, industry, and universities conducted research in the following areas: material processing, material characterization, modeling, life, applied life models, design techniques, vibration control, mechanical components, and tribology. Key issues, research accomplishments, and future directions are summarized in this publication.

Lewis base catalyzed aldol additions of chiral trichlorosilyl enolates and silyl enol ethers.

PubMed

Denmark, Scott E; Fujimori, Shinji; Pham, Son M

2005-12-23

[structures: see text] The consequences of double diastereodifferentiation in chiral Lewis base catalyzed aldol additions using chiral enoxysilanes derived from lactate, 3-hydroxyisobutyrate, and 3-hydroxybutyrate have been investigated. Trichlorosilyl enolates derived from the chiral methyl and ethyl ketones were subjected to aldolization in the presence of phosphoramides, and the intrinsic selectivity of these enolates and the external stereoinduction from chiral catalyst were studied. In the reactions with the lactate derived enolate, the strong internal stereoinduction dominated the stereochemical outcome of the aldol addition. For the 3-hydroxyisobutyrate- and 3-hydroxybutyrate derived enolates, the catalyst-controlled diastereoselectivities were observed, and the resident stereogenic centers exerted marginal influence. The corresponding trimethylsilyl enol ethers were employed in SiCl4/bisphosphoramide catalyzed aldol additions, and the effect of double diastereodifferentiation was also investigated. The overall diastereoselection of the process was again controlled by the strong external influence of the catalyst.

Use of facile mechanochemical method to functionalize carbon nanofibers with nanostructured polyaniline and their electrochemical capacitance

PubMed Central

2012-01-01

A facile approach to functionalize carbon nanofibers [CNFs] with nanostructured polyaniline was developed via in situ mechanochemical polymerization of polyaniline in the presence of chemically treated CNFs. The nanostructured polyaniline grafting on the CNF was mainly in a form of branched nanofibers as well as rough nanolayers. The good dispersibility and processability of the hybrid nanocomposite could be attributed to its overall nanostructure which enhanced its accessibility to the electrolyte. The mechanochemical oxidation polymerization was believed to be related to the strong Lewis acid characteristic of FeCl3 and the Lewis base characteristic of aniline. The growth mechanism of the hierarchical structured nanofibers was also discussed. After functionalization with the nanostructured polyaniline, the hybrid polyaniline/CNF composite showed an enhanced specific capacitance, which might be related to its hierarchical nanostructure and the interaction between the aromatic polyaniline molecules and the CNFs. PMID:22315992

Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

PubMed Central

Hintermann, Lukas; Perseghini, Mauro

2011-01-01

Summary Titanium-based Lewis acids catalyze the α-fluorination of β-ketoesters by electrophilic N–F-fluorinating reagents. Asymmetric catalysis with TADDOLato–titanium(IV) dichloride (TADDOL = α,α,α',α'-tetraaryl-(1,3-dioxolane-4,5-diyl)-dimethanol) Lewis acids produces enantiomerically enriched α-fluorinated β-ketoesters in up to 91% enantiomeric excess, with either F–TEDA (1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate)) in acetonitrile solution or NFSI (N-fluorobenzenesulfonimide) in dichloromethane solution as fluorinating reagents. The effects of various reaction parameters and of the TADDOL ligand structure on the catalytic activity and enantioselectivity were investigated. The absolute configuration of several fluorination products was assigned through correlation. Evidence for ionization of the catalyst complex by chloride dissociation, followed by generation of titanium β-ketoenolates as key reaction intermediates, was obtained. Based on the experimental findings, a general mechanistic sketch and a steric model of induction are proposed. PMID:22043253

Synthesis and spectral characterization of hydrazone derivative of furfural using experimental and DFT methods.

PubMed

Babu, N Ramesh; Subashchandrabose, S; Ali Padusha, M Syed; Saleem, H; Erdoğdu, Y

2014-01-01

The Spectral Characterization of (E)-1-(Furan-2-yl) methylene)-2-(1-phenylvinyl) hydrazine (FMPVH) were carried out by using FT-IR, FT-Raman and UV-Vis., Spectrometry. The B3LYP/6-311++G(d,p) level of optimization has been performed on the title compound. The conformational analysis was performed for this molecule, in which the cis and trans conformers were studied for spectral characterization. The recorded spectral results were compared with calculated results. The optimized bond parameters of FMPVH molecule was compared with X-ray diffraction data of related molecule. To study the intra-molecular charge transfers within the molecule the Lewis (bonding) and Non-Lewis (anti-bonding) structural calculation was performed. The Non-linear optical behavior of the title compound was measured using first order hyperpolarizability calculation. The atomic charges were calculated and analyzed. Copyright © 2013 Elsevier B.V. All rights reserved.

A Neutral Silicon/Phosphorus Frustrated Lewis Pair.

PubMed

Waerder, Benedikt; Pieper, Martin; Körte, Leif A; Kinder, Timo A; Mix, Andreas; Neumann, Beate; Stammler, Hans-Georg; Mitzel, Norbert W

2015-11-02

Frustrated Lewis pairs (FLPs) have a great potential for activation of small molecules. Most known FLP systems are based on boron or aluminum atoms as acid functions, few on zinc, and only two on boron-isoelectronic silicenium cation systems. The first FLP system based on a neutral silane, (C2F5)3SiCH2P(tBu)2 (1), was prepared from (C2F5)3SiCl with C2F5 groups of very high electronegativity and LiCH2P(tBu)2. 1 is capable of cleaving hydrogen, and adds CO2 and SO2. Hydrogen splitting was confirmed by H/D scrambling reactions. The structures of 1, its CO2 and SO2 adducts, and a decomposition product with CO2 were elucidated by X-ray diffraction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A descriptive study of Lewy body dementia with functional imaging support in a Chinese population: a preliminary study.

PubMed

Shea, Y F; Chu, L W; Lee, S C

2017-06-01

Lewy body dementia includes dementia with Lewy bodies and Parkinson's disease dementia. There have been limited clinical studies among Chinese patients with Lewy body dementia. This study aimed to review the presenting clinical features and identify risk factors for complications including falls, dysphagia, aspiration pneumonia, pressure sores, and mortality in Chinese patients with Lewy body dementia. We also wished to identify any difference in clinical features of patients with Lewy body dementia with and without an Alzheimer's disease pattern of functional imaging. We retrospectively reviewed 23 patients with Lewy body dementia supported by functional imaging. Baseline demographics, presenting clinical and behavioural and psychological symptoms of dementia, functional and cognitive assessment scores, and complications during follow-up were reviewed. Patients with Lewy body dementia were further classified as having an Alzheimer's disease imaging pattern if functional imaging demonstrated bilateral temporoparietal hypometabolism or hypoperfusion with or without precuneus and posterior cingulate gyrus hypometabolism or hypoperfusion. The pre-imaging accuracy of clinical diagnosis was 52%. In 83% of patients, behavioural and psychological symptoms of dementia were evident. Falls, dysphagia, aspiration pneumonia, pressure sores, and death occurred in 70%, 52%, 26%, 26%, and 30% of patients, respectively with corresponding event rates per person-years of 0.32, 0.17, 0.18, 0.08, and 0.10. Patients with aspiration pneumonia compared with those without were more likely to have dysphagia (100% vs 35%; P=0.01). Deceased patients with Lewy body dementia, compared with alive patients, had a higher (median [interquartile range]) presenting Clinical Dementia Rating score (1 [1-2] vs 0.5 [0.5-1.0]; P=0.01), lower mean (± standard deviation) baseline Barthel index (13 ± 7 vs 18 ± 4; P=0.04), and were more likely to be prescribed levodopa (86% vs 31%; P=0.03). Patients with Lewy body dementia with an Alzheimer's disease pattern of functional imaging, compared with those without the pattern, were younger at presentation (mean ± standard deviation, 73 ± 6 vs 80 ± 6 years; P=0.02) and had a lower Mini-Mental State Examination score at 1 year (15 ± 8 vs 22 ± 6; P=0.05). Falls, dysphagia, aspiration pneumonia, and pressure sores were common among patients with Lewy body dementia. Those with an Alzheimer's disease pattern of functional imaging had a younger age of onset and lower 1-year Mini-Mental State Examination score.

Coordination- and Redox-Noninnocent Behavior of Ambiphilic Ligands Containing Antimony.

PubMed

Jones, J Stuart; Gabbaï, François P

2016-05-17

Stimulated by applications in catalysis, the chemistry of ambiphilic ligands featuring both donor and acceptor functionalities has experienced substantial growth in the past several years. The unique opportunities in catalysis offered by ambiphilic ligands stem from the ability of their acceptor functionalities to play key roles via metal-ligand cooperation or modulation of the reactivity of the metal center. Ligands featuring group 13 centers, most notably boranes, as their acceptor functionalities have undoubtedly spearheaded these developments, with remarkable results having been achieved in catalytic hydrogenation and hydrosilylation. Motivated by these developments as well as by our fundamental interest in the chemistry of heavy group 15 elements, we became fascinated by the possibility of employing antimony centers as Lewis acids within ambiphilic ligands. The chemistry of antimony-based ligands, most often encountered as trivalent stibines, has historically been considered to mirror that of their lighter phosphorus-based congeners. There is growing evidence, however, that antimony-based ligands may display unique coordination behavior and reactivity. Additionally, despite the diverse Lewis acid and redox chemistry that antimony exhibits, there have been only limited efforts to explore this chemistry within the coordination sphere of a transition metal. By incorporation of antimony into the framework of polydentate ligands in order to enforce the main group metal-transition metal interaction, the effect of redox and coordination events at the antimony center on the structure, electronics, and reactivity of the metal complex may be investigated. This Account describes our group's continuing efforts to probe the coordination behavior, reactivity, and application of ambiphilic ligands incorporating antimony centers. Structural and theoretical studies have established that both Sb(III) and Sb(V) centers in polydentate ligands may act as Z-type ligands toward late transition metals. Although coordinated to a metal, the antimony centers in these complexes retain residual Lewis acidity, as evidenced by their ability to participate in anion binding. Anion binding events at the antimony center have been shown by structural, spectroscopic, and theoretical studies to perturb the antimony-transition metal interaction and in some cases to trigger reactivity at the metal center. Coordinated Sb(III) centers in polydentate ligands have also been found to readily undergo two-electron oxidation, generating strongly Lewis acidic Sb(V) centers in the coordination sphere of the metal. Theoretical studies suggest that oxidation of the coordinated antimony center induces an umpolung of the antimony-metal bond, resulting in depletion of electron density at the metal center. In addition to elucidating the fundamental coordination and redox chemistry of antimony-containing ambiphilic ligands, our work has demonstrated that these unusual behaviors show promise for use in a variety of applications. The ability of coordinated antimony centers to bind anions has been exploited for sensing applications, in which anion coordination at antimony leads to a colorimetric response via a change in the geometry about the metal center. In addition, the capacity of antimony Lewis acids to modulate the electron density of coordinated metals has proved to be key in facilitating photochemical activation of M-X bonds as well as antimony-centered redox-controlled catalysis.

Addiction-prone Lewis but not Fischer rats develop compulsive running that coincides with downregulation of nerve growth factor inducible-B and neuron-derived orphan receptor 1.

PubMed

Werme, M; Thorén, P; Olson, L; Brené, S

1999-07-15

We have examined the effects of chronic voluntary running for 30 d on the levels of nerve growth factor inducilble-B (NGFI-B) and neuron-derived orphan receptor 1 (NOR1) mRNAs in Fischer and Lewis rats. The aim was to compare the addiction-prone Lewis rat strain to the Fischer strain in a plausible model for natural reward. The Lewis strain ran markedly more than the Fischer strain, as indicated by the length of running per day when given free access to running wheels. Both strains progressively increased their amount of daily running. By day 14, Lewis rats had reached a maximal level corresponding to 10 km/d, which slowly decreased to approximately 8 km/d. Fischer rats ran considerably less, averaging approximately 1. 5 km/d by day 30. After 30 d of running, levels of mRNA encoding NGFI-B and Nor1 were decreased in cerebral cortex in Lewis but not Fischer rats. The downregulation of NGFI-B mRNA in Lewis rats could not be attenuated by the opioid receptor antagonist naloxone. Instead, naloxone by itself downregulated NGFI-B in striatum and cerebral cortex in both strains. In contrast, naloxone had no effect on Nor1 mRNA levels, although the running-induced downregulation of Nor1 was, in most cases, attenuated by naloxone. Data from the present study suggest that the same genetic factors contributing to the drug addiction-prone behavior of Lewis rats also control the excessive running behavior and that this coincides with downregulation of transcription factors of the NGFI-B family.

NGFI-B and nor1 mRNAs are upregulated in brain reward pathways by drugs of abuse: different effects in Fischer and Lewis rats.

PubMed

Werme, M; Olson, L; Brené, S

2000-03-10

The two inbred Fischer and Lewis rat strains display differences in acquisition of drug self-administration, suggesting genetic factors controlling the vulnerability to drugs of abuse. In this study, we analyzed the effects of acute and chronic cocaine and morphine on mRNAs encoding the NGFI-B/Nur77 family of nuclear orphan receptors in reward pathways in Fischer and Lewis rats. After a single injection of cocaine, a similar upregulation of NGFI-B mRNA in striatal subregions and cortex cinguli was seen in both Fischer and Lewis rats. In contrast, Nor1 mRNA was only significantly upregulated by cocaine in the Fischer rats. Morphine increased NGFI-B mRNA in medial caudate putamen and cortex cinguli in Lewis rats and Nor1 mRNA in medial caudate putamen in Fischer rats. Chronic cocaine upregulated NGFI-B mRNA in nucleus accumbens core, lateral caudate putamen and cingulate cortex in Fischer rats, whereas no effect was seen in Lewis rats. In contrast, Nor1 mRNA levels were upregulated in Lewis rats in medial caudate putamen and cingulate cortex after chronic cocaine and in cingulate cortex after chronic morphine. No effect on Nor1 mRNA levels was seen in Fischer rats after chronic treatments. Our results demonstrate different responses in addiction-prone Lewis rats as compared to the less addiction-prone Fischer rats with respect to NGFI-B and Nor1 mRNA regulation after acute and repeated administration of cocaine and morphine. Thus, we suggest that the transcription factors NGFI-B and Nor1 might be involved in the control of behaviors such as sensitized locomotor response, craving and aversion that appears after repeated administration of abused drugs.

Pareidolias: complex visual illusions in dementia with Lewy bodies.

PubMed

Uchiyama, Makoto; Nishio, Yoshiyuki; Yokoi, Kayoko; Hirayama, Kazumi; Imamura, Toru; Shimomura, Tatsuo; Mori, Etsuro

2012-08-01

Patients rarely experience visual hallucinations while being observed by clinicians. Therefore, instruments to detect visual hallucinations directly from patients are needed. Pareidolias, which are complex visual illusions involving ambiguous forms that are perceived as meaningful objects, are analogous to visual hallucinations and have the potential to be a surrogate indicator of visual hallucinations. In this study, we explored the clinical utility of a newly developed instrument for evoking pareidolic illusions, the Pareidolia test, in patients with dementia with Lewy bodies-one of the most common causes of visual hallucinations in the elderly. Thirty-four patients with dementia with Lewy bodies, 34 patients with Alzheimer's disease and 26 healthy controls were given the Pareidolia test. Patients with dementia with Lewy bodies produced a much greater number of pareidolic illusions compared with those with Alzheimer's disease or controls. A receiver operating characteristic analysis demonstrated that the number of pareidolias differentiated dementia with Lewy bodies from Alzheimer's disease with a sensitivity of 100% and a specificity of 88%. Full-length figures and faces of people and animals accounted for >80% of the contents of pareidolias. Pareidolias were observed in patients with dementia with Lewy bodies who had visual hallucinations as well as those who did not have visual hallucinations, suggesting that pareidolias do not reflect visual hallucinations themselves but may reflect susceptibility to visual hallucinations. A sub-analysis of patients with dementia with Lewy bodies who were or were not treated with donepzil demonstrated that the numbers of pareidolias were correlated with visuoperceptual abilities in the former and with indices of hallucinations and delusional misidentifications in the latter. Arousal and attentional deficits mediated by abnormal cholinergic mechanisms and visuoperceptual dysfunctions are likely to contribute to the development of visual hallucinations and pareidolias in dementia with Lewy bodies.

Pareidolias: complex visual illusions in dementia with Lewy bodies

PubMed Central

Uchiyama, Makoto; Yokoi, Kayoko; Hirayama, Kazumi; Imamura, Toru; Shimomura, Tatsuo; Mori, Etsuro

2012-01-01

Patients rarely experience visual hallucinations while being observed by clinicians. Therefore, instruments to detect visual hallucinations directly from patients are needed. Pareidolias, which are complex visual illusions involving ambiguous forms that are perceived as meaningful objects, are analogous to visual hallucinations and have the potential to be a surrogate indicator of visual hallucinations. In this study, we explored the clinical utility of a newly developed instrument for evoking pareidolic illusions, the Pareidolia test, in patients with dementia with Lewy bodies—one of the most common causes of visual hallucinations in the elderly. Thirty-four patients with dementia with Lewy bodies, 34 patients with Alzheimer’s disease and 26 healthy controls were given the Pareidolia test. Patients with dementia with Lewy bodies produced a much greater number of pareidolic illusions compared with those with Alzheimer’s disease or controls. A receiver operating characteristic analysis demonstrated that the number of pareidolias differentiated dementia with Lewy bodies from Alzheimer’s disease with a sensitivity of 100% and a specificity of 88%. Full-length figures and faces of people and animals accounted for >80% of the contents of pareidolias. Pareidolias were observed in patients with dementia with Lewy bodies who had visual hallucinations as well as those who did not have visual hallucinations, suggesting that pareidolias do not reflect visual hallucinations themselves but may reflect susceptibility to visual hallucinations. A sub-analysis of patients with dementia with Lewy bodies who were or were not treated with donepzil demonstrated that the numbers of pareidolias were correlated with visuoperceptual abilities in the former and with indices of hallucinations and delusional misidentifications in the latter. Arousal and attentional deficits mediated by abnormal cholinergic mechanisms and visuoperceptual dysfunctions are likely to contribute to the development of visual hallucinations and pareidolias in dementia with Lewy bodies. PMID:22649179

Redox and Lewis acid-base activities through an electronegativity-hardness landscape diagram.

PubMed

Das, Ranjita; Vigneresse, Jean-Louis; Chattaraj, Pratim Kumar

2013-11-01

Chemistry is the science of bond making and bond breaking which requires redistribution of electron density among the reactant partners. Accordingly acid-base and redox reactions form cardinal components in all branches of chemistry, e.g., inorganic, organic, physical or biochemistry. That is the reason it forms an integral part of the undergraduate curriculum all throughout the globe. In an electronegativity (χ)- hardness (η) landscape diagram the diagonal χ = η line separates reducing agents from oxidizing agents as well as Lewis acids from Lewis bases. While electronegativity is related to the degree of electron transfer between two reactants, hardness is related to the resistance to that process. Accordingly the electronegativities of oxidizing agents/Lewis acids are generally greater than the corresponding hardness values and the reverse is true for reducing agents/Lewis bases. Electrophiles and nucleophiles are also expected to follow similar trends.

Biology Students’ Initial Mental Model about Microorganism

NASA Astrophysics Data System (ADS)

Hamdiyati, Y.; Sudargo, F.; Redjeki, S.; Fitriani, A.

2017-02-01

The purpose of this study was to identify biology students’ initial mental model about microorganism. This research used descriptive method with 32 sixth semester biology students at Biology Education Departement-Universitas Pendidikan Indonesia as its respondents. Data was taken at the beginning of the 6th semester before respondents endure microbiology course. Instrument used to assess mental model was drawing-writing test in which it contains concepts such as structure of bacteria, archaea, virus, and fungi. Students were asked to describe their imagination about the structure of microorganisms and subsequently asked to explain the structure of microorganisms in writing through open-ended questions. Students’ response was then compared to scientists or experts’ mental models as the targeted mental model. Student mental models were categorized into five levels (levels 1-5), namely “there is no drawing/writing,” “wrong or irrelevant drawing/writing of question,” “partially correct drawing/writing,” “the drawing/writing that has some deficiencies,” and “completely correct and complete drawing/writing.” Results showed that the level of mental models through drawing or writing about the four concepts were varied. The highest level of mental models through drawing (D5) was found in the concept of bacteria, while the highest level of mental models through writing (W3) was found in the concept of bacteria, virus, and fungi. Mental model levels most commonly found in each concept through drawing-writing tests (D/W) were bacteria (D2/W2), Archaea (D1/W1 and D2/W2), virus (D3/W3), and fungi (D2/W1). From these results it is advisable to improve lectures and assessment strategy to enhance or complement students’ mental models about microorganisms.

An Integrated Perspective of Humanism and Supernaturalism for Education: C. S. Lewis's Version of Education

ERIC Educational Resources Information Center

Lee, Seung Chun

2013-01-01

This paper explores some theoretical reflections on the connection between C. S. Lewis's thoughts on the purpose and process of education and his understanding of supernatural human nature which has been relatively little explored. An introduction about Lewis's career as a college teacher blends into the background of this paper. It is followed by…

Interview with Smithsonian NASM Spacesuit Curator Dr. Cathleen Lewis

NASA Technical Reports Server (NTRS)

Lewis, Cathleen; Wright, Rebecca

2012-01-01

Dr. Cathleen Lewis was interviewed by Rebecca Wright during the presentation of an "Interview with Smithsonian NASM Spacesuit Curator Dr. Cathleen Lewis" on May 14, 2012. Topics included the care, size, and history of the spacesuit collection at the Smithsonian and the recent move to the state-of-the-art permanent storage facility at the Udvar-Hazy facility in Virginia.

Is there an attractive interaction between two methyl groups?

NASA Astrophysics Data System (ADS)

Zhuo, Hong-Ying; Jiang, Li-Xia; Li, Qing-Zhong; Li, Wen-Zuo; Cheng, Jian-Bo

2014-07-01

A weak interaction was found between the two methyl groups in the complexes of XCH3-CH3BH2 (X = F, CN, NO2, HCO, and SOCH3), where the former methyl group acts as a Lewis acid and the latter one as a Lewis base. This directional interaction has small interaction energy, accompanied with some small changes in geometry and spectroscopy. Stronger Lewis acids FYH3 (Y = Si, Ge, and Sn) as well as Lewis bases CH3BeH and CH3MgH were compared. Dispersion energy is the major source of attraction and electrostatic contribution grows up to exceed dispersion energy for stronger interactions.

Lewis Rodert Receiving a Collier Trophy from President Truman

NASA Image and Video Library

1947-12-21

Lewis Rodert, then of the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory, receives the Collier Trophy from President Harry Truman for his work in the design and development of an ice prevention system for aircraft. The accumulation of ice on an aircraft had been a critical issue for years. Rodert developed a method of transferring engine heat to the wings and other vulnerable components to prevent ice buildup. Rodert began his icing investigations at Langley Memorial Aeronautical Laboratory in 1936. The NACA ordered a Lockheed 12A aircraft to be built using Rodert’s deicing system. The aircraft successfully flew through icing conditions during the following winter. Soon thereafter the military incorporated the system into a Consolidated B-24D Liberator and several other military aircraft, including a North American XB-25F. Rodert and the NACA icing program transferred to the Lewis lab in Cleveland in 1946. In Cleveland, the focus turned to the study of cloud composition and the causes of icing. Rodert’s role at Lewis diminished over the ensuing years. Rodert was honored in 1947 for his Collier Trophy at ceremonies at Langley, Ames, and then finally Lewis.

Alignment Pins for Assembling and Disassembling Structures

NASA Technical Reports Server (NTRS)

Campbell, Oliver C.

2008-01-01

Simple, easy-to-use, highly effective tooling has been devised for maintaining alignment of bolt holes in mating structures during assembly and disassembly of the structures. The tooling was originally used during removal of a body flap from the space shuttle Atlantis, in which misalignments during removal of the last few bolts could cause the bolts to bind in their holes. By suitably modifying the dimensions of the tooling components, the basic design of the tooling can readily be adapted to other structures that must be maintained in alignment. The tooling includes tapered, internally threaded alignment pins designed to fit in the bolt holes in one of the mating structures, plus a draw bolt and a cup that are used to install or remove each alignment pin. In preparation for disassembly of two mating structures, external supports are provided to prevent unintended movement of the structures. During disassembly of the structures, as each bolt that joins the structures is removed, an alignment pin is installed in its place. Once all the bolts have been removed and replaced with pins, the pins maintain alignment as the structures are gently pushed or pulled apart on the supports. In assembling the two structures, one reverses the procedure described above: pins are installed in the bolt holes, the structures are pulled or pushed together on the supports, then the pins are removed and replaced with bolts. The figure depicts the tooling and its use. To install an alignment pin in a bolt hole in a structural panel, the tapered end of the pin is inserted from one side of the panel, the cup is placed over the pin on the opposite side of the panel, the draw bolt is inserted through the cup and threaded into the pin, the draw bolt is tightened to pull the pin until the pin is seated firmly in the hole, then the draw bolt and cup are removed, leaving the pin in place. To remove an alignment pin, the cup is placed over the pin on the first-mentioned side of the panel, the draw bolt is inserted through the cup and threaded into the pin, then the draw bolt is tightened to pull the pin out of the hole.

Clinical and cognitive correlates of visual hallucinations in dementia with Lewy bodies.

PubMed

Cagnin, Annachiara; Gnoato, Francesca; Jelcic, Nela; Favaretto, Silvia; Zarantonello, Giulia; Ermani, Mario; Dam, Mauro

2013-05-01

The presence of recurrent complex visual hallucinations (VHs) is a core feature of dementia with Lewy bodies (DLB). The aim of this study was to investigate which clinical and neuropsychological characteristics are associated with VHs and their predictive value over a 1 year follow-up. 81 DLB patients, 41 with (VH+) and 36 without (VH-) VHs, and 45 patients with Alzheimer's disease (AD), were enrolled. All participants underwent extensive neuropsychological testing. Visual-spatial and perceptual abilities were evaluated with the Visual and Object Space Perception (VOSP) battery. Fluctuations in attention, rapid eye movement sleep behaviour disorder (RBD) symptoms, extrapyramidal signs and behavioural disturbances were studied with dedicated clinical scales. The presence of VHs was associated with older age and later disease onset, but not with disease duration or with fluctuations, RBD or parkinsonism severity. Cognitive correlates of VHs were deficits in visual attention (digit cancellation: p<0.005) and executive functions (clock drawing: p<0.05; digit span forward: p<0.05) on a background of a slightly worse global cognitive performance (Mini-Mental State Examination: p=0.05). Visual-perceptual and visual-spatial deficits were significantly worse in DLB than in AD patients (VOSP subtests scores 1, 6, 7 and 8) but were not different in DLB VH+ and VH-, except for subtest 6. Poor performance in the visual attention task was an independent predictor of VHs. Impairment of visual-spatial and perceptual abilities in DLB represents a disease related cognitive signature, independent of the presence of VHs, for which it may represent a predisposing condition. Visual attention, instead, is the main cognitive determinant for the genesis of VHs.

Structural Integrity and Durability of Reusable Space Propulsion Systems

NASA Technical Reports Server (NTRS)

1991-01-01

A two-day conference on the structural integrity and durability of reusable space propulsion systems was held on 14 to 15 May 1991 at the NASA Lewis Research Center. Presentations were made by industry, university, and government researchers organized into four sessions: (1) aerothermodynamic loads; (2) instrumentation; (3) fatigue, fracture, and constitutive modeling; and (4) structural dynamics. The principle objectives were to disseminate research results and future plans in each of four areas. This publication contains extended abstracts and the visual material presented during the conference. Particular emphasis is placed on the Space Shuttle Main Engine (SSME) and the SSME turbopump.

Metallographic techniques for evaluation of thermal barrier coatings

NASA Technical Reports Server (NTRS)

Brindley, William J.; Leonhardt, Todd A.

1990-01-01

The performance of ceramic thermal barrier coatings is strongly dependent on the amount and shape of the porosity in the coating. Current metallographic techniques do not provide polished surfaces that are adequate for a repeatable interpretation of the coating structures. A technique recently developed at NASA-Lewis for preparation of thermal barrier coating sections combines epoxy impregnation, careful sectioning and polishing, and interference layering to provide previously unobtainable information on processing-induced porosity. In fact, increased contrast and less ambiguous structure developed by the method make automatic quantitative metallography a viable option for characterizing thermal barrier coating structures.

Progressive damage, fracture predictions and post mortem correlations for fiber composites

NASA Technical Reports Server (NTRS)

1985-01-01

Lewis Research Center is involved in the development of computational mechanics methods for predicting the structural behavior and response of composite structures. In conjunction with the analytical methods development, experimental programs including post failure examination are conducted to study various factors affecting composite fracture such as laminate thickness effects, ply configuration, and notch sensitivity. Results indicate that the analytical capabilities incorporated in the CODSTRAN computer code are effective in predicting the progressive damage and fracture of composite structures. In addition, the results being generated are establishing a data base which will aid in the characterization of composite fracture.

Evolution of microstructure and mechanical properties of steel in the course of pressing-drawing

NASA Astrophysics Data System (ADS)

Lezhnev, S. N.; Volokitina, I. E.; Volokitin, A. V.

2017-11-01

The combined continuous pressing-drawing process is proposed after a comprehensive analysis of available plastic structure-forming techniques taking into account the promising trends in their development. This combination of severe plastic deformation in equal-channel step die and drawing allows one to obtain a wire of desired size and shape in the cross section with an ultrafine-grained structure after a few deformation cycles. It also enables initial workpieces of any length to be processed and, therefore, allows one to obtain finished products up to several tens of meters in length. The aim of this study is to investigate the effect of new combined pressing-drawing technique of plastic deformation on the structure and mechanical properties of the steel. These studies have shown that the proposed deformation technique has a significant advantage of the techniques currently used to manufacture a steel wire.

The Mediation of Tools in the Development of Formal Mathematical Concepts: The Compass and the Circle as an Example.

ERIC Educational Resources Information Center

Chassapis, Dimitris

1999-01-01

Focuses on the process by which children develop a formal mathematical concept of the circle by using various instruments to draw circles within the context of a goal-directed drawing task. Concludes that the use of the compass in circle drawing structures the circle-drawing operation in a radically different fashion than circle tracers and…

Decreasing diameter fluctuation of polymer optical fiber with optimized drawing conditions

NASA Astrophysics Data System (ADS)

Çetinkaya, Onur; Wojcik, Grzegorz; Mergo, Pawel

2018-05-01

The diameter fluctuations of poly(methyl methacrylate) based polymer optical fibers, during drawing processes, have been comprehensively studied. In this study, several drawing parameters were selected for investigation; such as drawing tensions, preform diameters, preform feeding speeds, and argon flows. Varied drawing tensions were used to draw fibers, while other parameters were maintained at constant. At a later stage in the process, micro-structured polymer optical fibers were drawn under optimized drawing conditions. Fiber diameter deviations were reduced to 2.2%, when a 0.2 N drawing tension was employed during the drawing process. Higher drawing tensions led to higher diameter fluctuations. The Young’s modulus of fibers drawn with different tensions was also measured. Our results showed that fiber elasticity increased as drawing tensions decreased. The inhomogeneity of fibers was also determined by comparing the deviation of Young’s modulus.

75 FR 55313 - Final Environmental Impact Statement (FEIS) for Grow the Army Actions at Fort Lewis and the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-10

... decisions in the 2007 Army Growth and Force Structure Realignment Programmatic EIS (also referred to as the... of Public Works, Attention: IMWE-LEW-PWE (Mr. Paul T. Steucke, Jr.), Building 2012, Liggett Avenue..., Yakima Training Center, and McChord Air Force Base were designated a joint base and renamed ``Joint Base...

Structural and Acidic Properties of Niobia-Silica and Niobia-Alumina Aerogels

DTIC Science & Technology

1991-05-06

some weak Bronsted acidity. The silica aerogel supported niobia samples also had strong Lewis acidity as well as strong iv Bronsted acidity which was...NS25w or the silica aerogel supported niobia because of the formation of a distorted octahedral niobia-rigid silica interface. Isomerization of 1...67 2.1.2 Silica Aerogel .......................................................... 70 2.1.3 Alumina

The Effect of Fragmented Pathogenic α-Synuclein Seeds on Prion-like Propagation*

PubMed Central

Tarutani, Airi; Suzuki, Genjiro; Shimozawa, Aki; Nonaka, Takashi; Akiyama, Haruhiko; Hisanaga, Shin-ichi; Hasegawa, Masato

2016-01-01

Aggregates of abnormal proteins are widely observed in neuronal and glial cells of patients with various neurodegenerative diseases, and it has been proposed that prion-like behavior of these proteins can account for not only the onset but also the progression of these diseases. However, it is not yet clear which abnormal protein structures function most efficiently as seeds for prion-like propagation. In this study, we aimed to identify the most pathogenic species of α-synuclein (α-syn), the main component of the Lewy bodies and Lewy neurites that are observed in α-synucleinopathies. We prepared various forms of α-syn protein and examined their seeding properties in vitro in cells and in mouse experimental models. We also characterized these α-syn species by means of electron microscopy and thioflavin fluorescence assays and found that fragmented β sheet-rich fibrous structures of α-syn with a length of 50 nm or less are the most efficient promoters of accumulation of phosphorylated α-syn, which is the hallmark of α-synucleinopathies. These results indicate that fragmented amyloid-like aggregates of short α-syn fibrils are the key pathogenic seeds that trigger prion-like conversion. PMID:27382062

Structural and functional properties of prefibrillar α-synuclein oligomers

PubMed Central

Pieri, Laura; Madiona, Karine; Melki, Ronald

2016-01-01

The deposition of fibrillar alpha-synuclein (α-syn) within inclusions (Lewy bodies and Lewy neurites) in neurons and glial cells is a hallmark of synucleinopathies. α-syn populates a variety of assemblies ranging from prefibrillar oligomeric species to fibrils whose specific contribution to neurodegeneration is still unclear. Here, we compare the specific structural and biological properties of distinct soluble prefibrillar α-syn oligomers formed either spontaneously or in the presence of dopamine and glutaraldehyde. We show that both on-fibrillar assembly pathway and distinct dopamine-mediated and glutaraldehyde-cross-linked α-syn oligomers are only slightly effective in perturbing cell membrane integrity and inducing cytotoxicity, while mature fibrils exhibit the highest toxicity. In contrast to low-molecular weight and unstable oligomers, large stable α-syn oligomers seed the aggregation of soluble α-syn within reporter cells although to a lesser extent than mature α-syn fibrils. These oligomers appear elongated in shape. Our findings suggest that α-syn oligomers represent a continuum of species ranging from unstable low molecular weight particles to mature fibrils via stable elongated oligomers composed of more than 15 α-syn monomers that possess seeding capacity. PMID:27075649

Cordilleran front range structural features in northwest Montana interpreted from vintage seismic reflection data

NASA Astrophysics Data System (ADS)

Porter, Mason C.; Rutherford, Bradley S.; Speece, Marvin A.; Mosolf, Jesse G.

2016-04-01

Industry seismic reflection data spanning the Rocky Mountain Cordillera front ranges of northwest Montana were reprocessed and interpreted in this study. Five seismic profiles represent 160 km of deep reflection data collected in 1983 that span the eastern Purcell anticlinorium, Rocky Mountain Trench (RMT), Rocky Mountain Basal Décollement (RMBD), and Lewis thrust. The data were reprocessed using modern techniques including refraction statics, pre-stack time migration (PSTM), and pre- and post-stack depth migration. Results indicate the RMBD is 8-13 km below the Earth's surface and dip 3-10° west. Evidence for the autochthonous Mesoproterozoic Belt and basal Cambrian rocks beneath the RMBD is present in all of the profiles and appears to extend east of the RMT. The Lewis thrust was identified in the seismic profiles and appears to sole into the RMBD east of the RMT. The RMT fault system has a dip displacement of 3-4 km and forms a half graben filled with 1 km of unconsolidated Tertiary sedimentary deposits. The RMT and adjacent Flathead fault systems are interpreted to be structurally linked and may represent a synthetic, en echelon fault system.

Controlled fragmentation of multimaterial fibres and films via polymer cold-drawing.

PubMed

Shabahang, Soroush; Tao, Guangming; Kaufman, Joshua J; Qiao, Yangyang; Wei, Lei; Bouchenot, Thomas; Gordon, Ali P; Fink, Yoel; Bai, Yuanli; Hoy, Robert S; Abouraddy, Ayman F

2016-06-23

Polymer cold-drawing is a process in which tensile stress reduces the diameter of a drawn fibre (or thickness of a drawn film) and orients the polymeric chains. Cold-drawing has long been used in industrial applications, including the production of flexible fibres with high tensile strength such as polyester and nylon. However, cold-drawing of a composite structure has been less studied. Here we show that in a multimaterial fibre composed of a brittle core embedded in a ductile polymer cladding, cold-drawing results in a surprising phenomenon: controllable and sequential fragmentation of the core to produce uniformly sized rods along metres of fibre, rather than the expected random or chaotic fragmentation. These embedded structures arise from mechanical-geometric instabilities associated with 'neck' propagation. Embedded, structured multimaterial threads with complex transverse geometry are thus fragmented into a periodic train of rods held stationary in the polymer cladding. These rods can then be easily extracted via selective dissolution of the cladding, or can self-heal by thermal restoration to re-form the brittle thread. Our method is also applicable to composites with flat rather than cylindrical geometries, in which case cold-drawing leads to the break-up of an embedded or coated brittle film into narrow parallel strips that are aligned normally to the drawing axis. A range of materials was explored to establish the universality of this effect, including silicon, germanium, gold, glasses, silk, polystyrene, biodegradable polymers and ice. We observe, and verify through nonlinear finite-element simulations, a linear relationship between the smallest transverse scale and the longitudinal break-up period. These results may lead to the development of dynamical and thermoreversible camouflaging via a nanoscale Venetian-blind effect, and the fabrication of large-area structured surfaces that facilitate high-sensitivity bio-detection.

Controlled fragmentation of multimaterial fibres and films via polymer cold-drawing

NASA Astrophysics Data System (ADS)

Shabahang, Soroush; Tao, Guangming; Kaufman, Joshua J.; Qiao, Yangyang; Wei, Lei; Bouchenot, Thomas; Gordon, Ali P.; Fink, Yoel; Bai, Yuanli; Hoy, Robert S.; Abouraddy, Ayman F.

2016-06-01

Polymer cold-drawing is a process in which tensile stress reduces the diameter of a drawn fibre (or thickness of a drawn film) and orients the polymeric chains. Cold-drawing has long been used in industrial applications, including the production of flexible fibres with high tensile strength such as polyester and nylon. However, cold-drawing of a composite structure has been less studied. Here we show that in a multimaterial fibre composed of a brittle core embedded in a ductile polymer cladding, cold-drawing results in a surprising phenomenon: controllable and sequential fragmentation of the core to produce uniformly sized rods along metres of fibre, rather than the expected random or chaotic fragmentation. These embedded structures arise from mechanical-geometric instabilities associated with ‘neck’ propagation. Embedded, structured multimaterial threads with complex transverse geometry are thus fragmented into a periodic train of rods held stationary in the polymer cladding. These rods can then be easily extracted via selective dissolution of the cladding, or can self-heal by thermal restoration to re-form the brittle thread. Our method is also applicable to composites with flat rather than cylindrical geometries, in which case cold-drawing leads to the break-up of an embedded or coated brittle film into narrow parallel strips that are aligned normally to the drawing axis. A range of materials was explored to establish the universality of this effect, including silicon, germanium, gold, glasses, silk, polystyrene, biodegradable polymers and ice. We observe, and verify through nonlinear finite-element simulations, a linear relationship between the smallest transverse scale and the longitudinal break-up period. These results may lead to the development of dynamical and thermoreversible camouflaging via a nanoscale Venetian-blind effect, and the fabrication of large-area structured surfaces that facilitate high-sensitivity bio-detection.

Comparison of standard and Lewis ECG in detection of atrioventricular dissociation in patients with wide QRS tachycardia.

PubMed

Aksu, Uğur; Kalkan, Kamuran; Gülcü, Oktay; Topcu, Selim; Sevimli, Serdar; Aksakal, Enbiya; Ipek, Emrah; Açıkel, Mahmut; Tanboğa, Ibrahim Halil

2016-12-15

The atrioventricular (AV) dissociation, which is frequently used in differential diagnosis of wide QRS complex tachycardia (WQCT), is the most specific finding of ventricular tachycardia (VT) with lower sensitivity. Herein, we aimed to show the importance of Lewis lead ECG records to detect 'visible p waves' during WQCT. A total of 21 consecutive patients who underwent electrophysiologic study (EPS) were included in the study. During EPS, by using a quadripolar diagnostic catheter directed to the right ventricular apex, a fixed stimulus was given and the ventriculoatrial (VA) Wenkebach point was found, and a VT was simulated by a RV apical stimulus at 300ms. The standard and Lewis lead ECG records were taken during this procedure. We detected 'visible p waves' in 7 (33.3%) and 14 (66.7%) patients in the standard and Lewis lead ECG groups, respectively. In terms of the 'visible p waves', there was a statistically significant difference between groups (p=0.022). The sensitivity of standard and Lewis lead ECG in determination of the visible p waves was 33.3% and 66.7%, respectively. The Lewis lead ECG can be more informative about AV dissociation than the standard 12 lead ECG. As a result, we could suggest the assessment of the Lewis lead ECG recording in addition to the standard 12 lead ECG in differential diagnosis of VT in patients with WQCT. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Reliability and risk assessment of structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1991-01-01

Development of reliability and risk assessment of structural components and structures is a major activity at Lewis Research Center. It consists of five program elements: (1) probabilistic loads; (2) probabilistic finite element analysis; (3) probabilistic material behavior; (4) assessment of reliability and risk; and (5) probabilistic structural performance evaluation. Recent progress includes: (1) the evaluation of the various uncertainties in terms of cumulative distribution functions for various structural response variables based on known or assumed uncertainties in primitive structural variables; (2) evaluation of the failure probability; (3) reliability and risk-cost assessment; and (4) an outline of an emerging approach for eventual certification of man-rated structures by computational methods. Collectively, the results demonstrate that the structural durability/reliability of man-rated structural components and structures can be effectively evaluated by using formal probabilistic methods.

Two Tracks of Thought: A Structural Model of the Test for Creative Thinking-Drawing Production (TCT-DP)

ERIC Educational Resources Information Center

Nogueira, Sara Ibérico; Almeida, Leonor S.; Lima, Tiago Souza

2017-01-01

The Test for Creative Thinking-Drawing Production (TCT-DP, Urban & Jellen, 1986) is one of the most used instruments for the assessment of creative potential. Few studies exist regarding its factorial structure, and all of them were limited to using an exploratory approach. The aim of this research was to assess the factorial structure of the…

NACA Study of Crash Fires with a Fairchild C-82 Packet

NASA Image and Video Library

1950-06-21

Researchers at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory purposely crash a Fairchild C-82 Packet aircraft to study flame propagation. A rash of passenger aircraft crashes in 1946 and 1947 spurred a White House call for an investigatory board staffed by members of the Civil Aeronautics Board, military, and the NACA. The group addressed fire segregation, extinguishment, and prevention. The NACA established a Subcommittee on Aircraft Fire Prevention in February 1948 to coordinate its efforts. The Lewis team simulated situations in which an aircraft failed to become airborne during takeoff resulting in crashes into embankments and other objects. The Lewis researchers initially used surplus C-46 and C-82 military transport planes. In these situations, the aircraft generally suffered damage to its fuel system and other components, but was structurally survivable. The aircraft were mounted to a rail that ran down a 1700-foot long test runway. The aircraft was secured at the starting point with an anchor pier so it could get its engines up to takeoff speed before launching down the track. Barriers at the end of the runway were designed to simulate a variety of different types of crashes. Telemetry and high-speed cameras were crucial elements in these studies. The preliminary testing phase identified potential ignition sources and analyzed the spread of flammable materials.

Life assessment of structural components using inelastic finite element analyses

NASA Technical Reports Server (NTRS)

Arya, Vinod K.; Halford, Gary R.

1993-01-01

The need for enhanced and improved performance of structural components subject to severe cyclic thermal/mechanical loadings, such as in the aerospace industry, requires development of appropriate solution technologies involving time-dependent inelastic analyses. Such analyses are mandatory to predict local stress-strain response and to assess more accurately the cyclic life time of structural components. The NASA-Lewis Research Center is cognizant of this need. As a result of concerted efforts at Lewis during the last few years, several such finite element solution technologies (in conjunction with the finite element program MARC) were developed and successfully applied to numerous uniaxial and multiaxial problems. These solution technologies, although developed for use with MARC program, are general in nature and can easily be extended for adaptation with other finite element programs such as ABAQUS, ANSYS, etc. The description and results obtained from two such inelastic finite element solution technologies are presented. The first employs a classical (non-unified) creep-plasticity model. An application of this technology is presented for a hypersonic inlet cowl-lip problem. The second of these technologies uses a unified creep-plasticity model put forth by Freed. The structural component for which this finite element solution technology is illustrated, is a cylindrical rocket engine thrust chamber. The advantages of employing a viscoplastic model for nonlinear time-dependent structural analyses are demonstrated. The life analyses for cowl-lip and cylindrical thrust chambers are presented. These analyses are conducted by using the stress-strain response of these components obtained from the corresponding finite element analyses.

An Alternative Proposition to Lewis' Views on the "Constructions of Professional Identity in a Dynamic Higher Education Sector"

ERIC Educational Resources Information Center

Feather, Denis

2015-01-01

This paper offers an alternative proposition to that of Lewis on identity and professional identity in higher education (HE). The proposition is provided from the narratives of 26 individual interviewees who deliver HE in college-based higher education, a viewpoint not considered by Lewis, who tends to adopt a more generalist view. Where Lewis…

Oral Interpretation of C.S. Lewis'"Narnia Tales": A Refracting of "Pictures."

ERIC Educational Resources Information Center

Keefe, Carolyn

"The Chronicles of Narnia" are a series of seven fairy tales written by C.S. Lewis that have become popular with both children and adults. Lewis points to five aspects of the fairy tale form that made the form suitable for expressing the images he saw. The aspects are: (1) no love interest; (2) no close psychology; (3) severe restraints…

11. Photocopy of drawing, February 1958. WATERTOWN ARSENAL REACTOR, SHIELD ...

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

11. Photocopy of drawing, February 1958. WATERTOWN ARSENAL REACTOR, SHIELD STRUCTURE, SECTIONS, AND PLANS. Bendix Aviation Corporation; and Giffels & Vallet, Inc., L. Rosetti, Associated Architects and Engineers, Detroit, Michigan. Drawing Number 53-198. (Original: AMTL Engineering Division, Watertown). - Watertown Arsenal, Building No. 100, Wooley Avenue, Watertown, Middlesex County, MA

Understanding Molecular Genetics through a Drawing-Based Activity

ERIC Educational Resources Information Center

Rotbain, Yosi; Marbach-Ad, Gili; Stavy, Ruth

2005-01-01

The activity uses drawings typically found in textbooks, engaging students in physical and mental activities such as drawing, painting and figure completion--as well as finding missing words and answering guiding questions. The activity deals with three topics: the structure of DNA, DNA replication and protein synthesis. In this study we…

13. Photographic copy of photocopy of bridge drawing, plans and ...

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

13. Photographic copy of photocopy of bridge drawing, plans and elevations (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 5 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

14. Photographic copy of photocopy of bridge drawing, reinforced rod ...

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

14. Photographic copy of photocopy of bridge drawing, reinforced rod specifications (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 6 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

Figure Structure, Figure Action, and Framing in Drawings by American and Egyptian Children.

ERIC Educational Resources Information Center

Wilson, Brent; Wilson, Marjorie

1979-01-01

The purpose of this study is to investigate the interaction of biological unfolding and culturally related factors on sequences of narrative figure drawings by American and Egyptian elementary students. Findings support hypotheses relating to the interaction of natural and nurtural influences on children's drawings. (Author/SJL)

Design principles for nickel hydrogen cells and batteries

NASA Technical Reports Server (NTRS)

Thaller, L. H.

1985-01-01

Nickel hydrogen cells, and more recently, bipolar batteries have been built by a variety of organizations. The design principles that have been used by the technology group at the Lewis Research Center draw upon their extensive background in separator technology, alkaline fuel cell technology, and several alkaline cell technology areas. These design principles have been incorporated into both the more contemporary individual pressure vessel (IPV) designs that were pioneered by other groups, as well as the more recent bipolar battery designs using active cooling that are being developed at LeRC and their contractors. These principles are rather straightforward applications of capillary force formalisms, coupled with the slowly developing data base resulting from careful post test analyses. The objective of this overall effort is directed towards the low Earth orbit (LEO) application where the cycle life requirements are much more severe than the geosynchronous orbit (GEO) application. Nickel hydrogen cells have already been successfully flown in an increasing number of GEO missions.

Sudden Death: An Uncommon Occurrence in Dementia with Lewy Bodies.

PubMed

Molenaar, Joery P; Wilbers, Joyce; Aerts, Marjolein B; Leijten, Quinten H; van Dijk, Jan G; Esselink, Rianne A; Bloem, Bastiaan R

2016-01-01

We present a 75-year-old woman with dementia and parkinsonism who developed severe orthostatic hypotension and eventually died. Autopsy revealed extensive Lewy body formation in the midbrain, limbic system, intermediate spinal cord, and medulla oblongata. Furthermore, a vast amount of Lewy bodies was seen in the paravertebral sympathetic ganglia which likely explained the severe autonomic failure. We speculate that this autonomic failure caused sudden death through dysregulation of respiration or heart rhythm, reminiscent of sudden death in multiple system atrophy (MSA). Clinicians should be aware of this complication in patients presenting with parkinsonism and autonomic dysfunction, and that sudden death may occur in dementia with Lewy bodies (DLB) as it does in MSA.

Neuropathology of dementia in Parkinson's disease: a prospective, community-based study.

PubMed

Aarsland, Dag; Perry, Robert; Brown, Andrew; Larsen, Jan P; Ballard, Clive

2005-11-01

Twenty-two patients with Parkinson's disease drawn from a community-based study were followed prospectively until their deaths. Even though 18 patients had dementia, none fulfilled Braak and Braak or The National Institute on Aging and Ronald and Nancy Reagan Institute of the Alzheimer's Association, whereas all patients had limbic or neocortical Lewy body disease. The Lewy body score and Braak and Braak stage were significantly associated with the rate of cognitive decline, but only the Lewy body score was associated with the rate of cognitive decline in the univariate analyses. This study strongly suggests that Lewy body disease is the main substrate driving the progression of cognitive impairment in Parkinson's disease.

Theoretical evidence of charge transfer interaction between SO₂ and deep eutectic solvents formed by choline chloride and glycerol.

PubMed

Li, Hongping; Chang, Yonghui; Zhu, Wenshuai; Wang, Changwei; Wang, Chao; Yin, Sheng; Zhang, Ming; Li, Huaming

2015-11-21

The nature of the interaction between deep eutectic solvents (DESs), formed by ChCl and glycerol, and SO2 has been systematically investigated using the M06-2X density functional combined with cluster models. Block-localized wave function energy decomposition (BLW-ED) analysis shows that the interaction between SO2 and DESs is dominated by a charge transfer interaction. After this interaction, the SO2 molecule becomes negatively charged, whereas the ChCl-glycerol molecule is positively charged, which is the result of Lewis acid-base interaction. The current result affords a theoretical proof that it is highly useful and efficient to manipulate the Lewis acidity of absorbents for SO2 capture. Moreover, hydrogen bonding as well as electrostatic interactions may also contribute to the stability of the complex. Structure analysis shows that solvent molecules will adjust their geometries to interact with SO2. In addition, the structure of SO2 is barely changed after interaction. The interaction energy between different cluster models and SO2 ranges from -6.8 to -14.4 kcal mol(-1). It is found that the interaction energy is very sensitive to the solvent structure. The moderate interaction between ChCl-glycerol and SO2 is consistent with the concept that highly efficient solvents for SO2 absorption should not only be solvable but also regenerable.

The pedagogical potential of drawing and writing in a primary science multimodal unit

NASA Astrophysics Data System (ADS)

Wilson, Rachel E.; Bradbury, Leslie U.

2016-11-01

In consideration of the potential of drawing and writing as assessment and learning tools, we explored how early primary students used these modes to communicate their science understandings. The context for this study was a curricular unit that incorporated multiple modes of representation in both the presentation of information and production of student understanding with a focus on the structure and function of carnivorous plants (CPs). Two science teacher educators and two first-grade teachers in the United States co-planned and co-taught a multimodal science unit on CP structure and function that included multiple representations of Venus flytraps (VFTs): physical specimens, photographs, videos, text, and discussions. Pre- and post-assessment student drawings and writings were statistically compared to note significant changes, and pre- and post-assessment writings were qualitatively analysed to note themes in student ideas. Results indicate that students increased their knowledge of VFT structure and function and synthesised information from multiple modes. While students included more structures of the VFT in their drawings, they were better able to describe the functions of structures in their writings. These results suggest the benefits for student learning and assessment of having early primary students represent their science understandings in multiple modes.

Distance Learning With NASA Lewis Research Center's Learning Technologies Project

NASA Technical Reports Server (NTRS)

Petersen, Ruth

1998-01-01

The NASA Lewis Research Center's Learning Technologies Project (LTP) has responded to requests from local school district technology coordinators to provide content for videoconferencing workshops. Over the past year we have offered three teacher professional development workshops that showcase NASA Lewis-developed educational products and NASA educational Internet sites. In order to determine the direction of our involvement with distance learning, the LTP staff conducted a survey of 500 U.S. schools. We received responses from 72 schools that either currently use distance learning or will be using distance learning in 98-99 school year. The results of the survey are summarized in the article. In addition, the article provides information on distance learners, distance learning technologies, and the NASA Lewis LTP videoconferencing workshops. The LTP staff will continue to offer teacher development workshops through videoconferencing during the 98-99 school year. We hope to add workshops on new educational products as they are developed at NASA Lewis.

Designed Synthesis of Mesoporous Solid-Supported Lewis Acid-Base Pairs and Their CO2 Adsorption Behaviors.

PubMed

Zakharova, Maria V; Masoumifard, Nima; Hu, Yimu; Han, Jongho; Kleitz, Freddy; Fontaine, Frédéric-Georges

2018-04-18

Conventional amines and phosphines, such as diethylenetriamine, diphenylpropylphosphine, triethylamine, and tetramethylpiperidine, were grafted or impregnated on the surface of metalated SBA-15 materials, such as Ti-, Al-, and Zr-SBA-15, to generate air-stable solid-supported Lewis acid-base pairs. The Lewis acidity of the metalated materials before and after the introduction of Lewis bases was verified by means of pyridine adsorption-Fourier transform infrared spectroscopy. Detailed characterization of the materials was achieved by solid-state 13 C and 31 P MAS NMR spectroscopy, low-temperature N 2 physisorption, X-ray photoelectron spectroscopy, and energy-dispersive X-ray mapping analyses. Study of their potential interactions with CO 2 was performed using CO 2 adsorption isotherm experiments, which provided new insights into their applicability as solid CO 2 adsorbents. A correlation between solid-supported Lewis acid-base pair strength and the resulting affinity to CO 2 is discussed based on the calculation of isosteric enthalpy of adsorption.

Summary of NASA-Lewis Research Center solar heating and cooling and wind energy programs

NASA Technical Reports Server (NTRS)

Vernon, R. W.

1975-01-01

NASA is planning to construct and operate a solar heating and cooling system in conjunction with a new office building being constructed at Langley Research Center. The technology support for this project will be provided by a solar energy program underway at NASA's Lewis Research Center. The solar program at Lewis includes: testing of solar collectors with a solar simulator, outdoor testing of collectors, property measurements of selective and nonselective coatings for solar collectors, and a solar model-systems test loop. NASA-Lewis has been assisting the National Science Foundation and now the Energy Research and Development Administration in planning and executing a national wind energy program. The areas of the wind energy program that are being conducted by Lewis include: design and operation of a 100 kW experimental wind generator, industry-designed and user-operated wind generators in the range of 50 to 3000 kW, and supporting research and technology for large wind energy systems. An overview of these activities is provided.

Surgical Anatomy and Microvascular Surgical Technique Relevant to Experimental Renal Transplant in Rat Employing Aortic and Inferior Venacaval Conduits.

PubMed

Shrestha, Badri Man; Haylor, John

2017-11-15

Rat models of renal transplant are used to investigate immunologic processes and responses to therapeutic agents before their translation into routine clinical practice. In this study, we have described details of rat surgical anatomy and our experiences with the microvascular surgical technique relevant to renal transplant by employing donor inferior vena cava and aortic conduits. For this study, 175 rats (151 Lewis and 24 Fisher) were used to establish the Fisher-Lewis rat model of chronic allograft injury at our institution. Anatomic and technical details were recorded during the period of training and establishment of the model. A final group of 12 transplanted rats were studied for an average duration of 51 weeks for the Lewis-to-Lewis isografts (5 rats) and 42 weeks for the Fisher-to-Lewis allografts (7 rats). Functional measurements and histology confirmed the diagnosis of chronic allograft injury. Mastering the anatomic details and microvascular surgical techniques can lead to the successful establishment of an experimental renal transplant model.

Chemoselective Polymerization of Polar Divinyl Monomers with Rare-Earth/Phosphine Lewis Pairs.

PubMed

Xu, Pengfei; Wu, Lei; Dong, Liqiu; Xu, Xin

2018-02-08

This work reports the chemoselective polymerization of polar divinyl monomers, including allyl methacrylate (AMA), vinyl methacrylate (VMA), and 4-vinylbenzyl methacrylate (VBMA), by using simple Lewis pairs comprised of homoleptic rare-earth (RE) aryloxide complexes RE(OAr)₃ (RE = Sc ( 1 ), Y ( 2 ), Sm ( 3 ), La ( 4 ), Ar = 2,6- t Bu₂C₆H₃) and phosphines PR₃ (R = Ph, Cy, Et, Me). Catalytic activities of polymerizations relied heavily upon the cooperation of Lewis acid and Lewis base components. The produced polymers were soluble in common organic solvents and often had a narrow molecular weight distribution. A highly syndiotactic poly(allyl methacrylate) (PAMA) with rr ~88% could be obtained by the scandium complex 1 /PEt₃ pair at -30 °C. In the case of poly(4-vinylbenzyl methacrylate) (PVBMA), it could be post-functionalized with PhCH₂SH. Mechanistic study, including the isolation of the zwitterionic active species and the end-group analysis, revealed that the frustrated Lewis pair (FLP)-type addition was the initiating step in the polymerization.

13. Photographic copy of original construction drawing dated May 5, ...

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

13. Photographic copy of original construction drawing dated May 5, 1935, from the files at the Office of the Chief Engineer, U.S. Fish and Wildlife Service Regional Office, Denver. STRUCTURAL DETAILS GATE STRUCTURE 320 - J. Clark Salyer National Wildlife Refuge, Dam 320, Along Lower Souris River, Kramer, Bottineau County, ND

Process metallurgy simulation for metal drawing process optimization by using two-scale finite element method

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

Nakamachi, Eiji; Yoshida, Takashi; Yamaguchi, Toshihiko

2014-10-06

We developed two-scale FE analysis procedure based on the crystallographic homogenization method by considering the hierarchical structure of poly-crystal aluminium alloy metal. It can be characterized as the combination of two-scale structure, such as the microscopic polycrystal structure and the macroscopic elastic plastic continuum. Micro polycrystal structure can be modeled as a three dimensional representative volume element (RVE). RVE is featured as by 3×3×3 eight-nodes solid finite elements, which has 216 crystal orientations. This FE analysis code can predict the deformation, strain and stress evolutions in the wire drawing processes in the macro- scales, and further the crystal texture andmore » hardening evolutions in the micro-scale. In this study, we analyzed the texture evolution in the wire drawing processes by our two-scale FE analysis code under conditions of various drawing angles of dice. We evaluates the texture evolution in the surface and center regions of the wire cross section, and to clarify the effects of processing conditions on the texture evolution.« less

Process metallurgy simulation for metal drawing process optimization by using two-scale finite element method

NASA Astrophysics Data System (ADS)

Nakamachi, Eiji; Yoshida, Takashi; Kuramae, Hiroyuki; Morimoto, Hideo; Yamaguchi, Toshihiko; Morita, Yusuke

2014-10-01

We developed two-scale FE analysis procedure based on the crystallographic homogenization method by considering the hierarchical structure of poly-crystal aluminium alloy metal. It can be characterized as the combination of two-scale structure, such as the microscopic polycrystal structure and the macroscopic elastic plastic continuum. Micro polycrystal structure can be modeled as a three dimensional representative volume element (RVE). RVE is featured as by 3×3×3 eight-nodes solid finite elements, which has 216 crystal orientations. This FE analysis code can predict the deformation, strain and stress evolutions in the wire drawing processes in the macro- scales, and further the crystal texture and hardening evolutions in the micro-scale. In this study, we analyzed the texture evolution in the wire drawing processes by our two-scale FE analysis code under conditions of various drawing angles of dice. We evaluates the texture evolution in the surface and center regions of the wire cross section, and to clarify the effects of processing conditions on the texture evolution.

Biofluid-Based Detection of the Migration Switch in Prostate Cancer to Predict Metastatic Disease

DTIC Science & Technology

2016-09-01

developed with a laboratory in oncology studying osteosarcoma using Dr. Lewis’ in house imaging platforms. 15. SUBJECT TERMS Metastasis, motility...that may have a role in breast cancer. Another in-house collaboration was developed with a laboratory in oncology studying osteosarcoma using Dr. Lewis...Lewis. Quantitative Analysis of human Cancer Cell Extravasation Using Intravital Imaging, Department of Oncology , University of Alberta (2016) Vol. 1458

Lewis Research Center space station electric power system test facilities

NASA Technical Reports Server (NTRS)

Birchenough, Arthur G.; Martin, Donald F.

1988-01-01

NASA Lewis Research Center facilities were developed to support testing of the Space Station Electric Power System. The capabilities and plans for these facilities are described. The three facilities which are required in the Phase C/D testing, the Power Systems Facility, the Space Power Facility, and the EPS Simulation Lab, are described in detail. The responsibilities of NASA Lewis and outside groups in conducting tests are also discussed.

In the Footsteps of the Third Spanish Expedition: James Mackay and John T. Evans's Impact on the Lewis and Clark Expedition

ERIC Educational Resources Information Center

Witte, Kevin C.

2006-01-01

The odyssey of the Lewis and Clark Expedition continues to capture the hearts of those who love tales of adventure and unknown lands. In light of the bicentennial celebration that began in 2003 and continued through 2006, the popularity and aggrandizement of Meriwether Lewis, William Clark, and their Corps of Discovery has never been greater.…

A dual Lewis base activation strategy for enantioselective carbene-catalyzed annulations.

PubMed

Izquierdo, Javier; Orue, Ane; Scheidt, Karl A

2013-07-24

A dual activation strategy integrating N-heterocyclic carbene (NHC) catalysis and a second Lewis base has been developed. NHC-bound homoenolate equivalents derived from α,β-unsaturated aldehydes combine with transient reactive o-quinone methides in an enantioselective formal [4 + 3] fashion to access 2-benzoxopinones. The overall approach provides a general blueprint for the integration of carbene catalysis with additional Lewis base activation modes.

Human Milk Oligosaccharides and Lewis Blood Group: Individual High-Throughput Sample Profiling to Enhance Conclusions From Functional Studies12

PubMed Central

Blank, Dennis; Dotz, Viktoria; Geyer, Rudolf; Kunz, Clemens

2012-01-01

Human milk oligosaccharides (HMO) are discussed to play a crucial role in an infant’s development. Lewis blood group epitopes, in particular, seem to remarkably contribute to the beneficial effects of HMO. In this regard, large-scale functional human studies could provide evidence of the variety of results from in vitro investigations, although increasing the amount and complexity of sample and data handling. Therefore, reliable screening approaches are needed. To predict the oligosaccharide pattern in milk, the routine serological Lewis blood group typing of blood samples can be applied due to the close relationship between the biosynthesis of HMO and the Lewis antigens on erythrocytes. However, the actual HMO profile of the individual samples does not necessarily correspond to the serological determinations. This review demonstrates the capabilities of merging the traditional serological Lewis blood group typing with the additional information provided by the comprehensive elucidation of individual HMO patterns by means of state-of-the-art analytics. Deduced from the association of the suggested HMO biosynthesis with the Lewis blood group, the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry profiles of oligosaccharides in individual milk samples exemplify the advantages and the limitations of sample assignment to distinct groups. PMID:22585923

The Lewis A phenotype is a restriction factor for Rotateq and Rotarix vaccine-take in Nicaraguan children.

PubMed

Bucardo, Filemón; Nordgren, Johan; Reyes, Yaoska; Gonzalez, Fredman; Sharma, Sumit; Svensson, Lennart

2018-01-24

Histo-blood group antigens (HBGAs) and the Lewis and secretor antigens are associated with susceptibility to rotavirus infection in a genotype-dependent manner. Nicaraguan children were prospectively enrolled in two cohorts vaccinated with either RotaTeq RV5 (n = 68) or Rotarix RV1 (n = 168). Lewis and secretor antigens were determined by saliva phenotyping and genotyping. Seroconversion was defined as a 4-fold increase in plasma IgA antibody titer 1 month after administration of the first dose of the vaccine. Regardless of the vaccine administered, significantly fewer of the children with Lewis A phenotype (0/14) seroconverted after receiving the first vaccine dose compared to 26% (45/175) of those with the Lewis B phenotype and 32% (15/47) of the Lewis negative individuals (P < 0.01). Furthermore, following administration of the RV1 vaccine, secretor-positive ABO blood group B children seroconverted to a significantly lesser extent (5%) compared to secretor-positive children with ABO blood groups A (26%) and O (27%) (P < 0.05). Other factors such as pre-vaccination titers, sex, breastfeeding, and calprotectin levels did not influence vaccine-take. Differences in HBGA expression appear to be a contributing factor in the discrepancy in vaccine-take and thus, in vaccine efficacy in different ethnic populations.

Research and Technology, 1998

NASA Technical Reports Server (NTRS)

1999-01-01

This report selectively summarizes the NASA Lewis Research Center's research and technology accomplishments for the fiscal year 1998. It comprises 134 short articles submitted by the staff scientists and engineers. The report is organized into five major sections: Aeronautics, Research and Technology, Space, Engineering and Technical Services, and Commercial Technology. A table of contents and an author index have been developed to assist readers in finding articles of special interest. This report is not intended to he a comprehensive summary of all the research and technology work done over the past fiscal year. Most of the work is reported in Lewis-published technical reports, journal articles, and presentations prepared by Lewis staff and contractors. In addition, university grants have enabled faculty members and graduate students to engage in sponsored research that is reported at technical meetings or in journal articles. For each article in this report, a Lewis contact person has been identified, and where possible, reference documents are listed so that additional information can be easily obtained. The diversity of topics attests to the breadth of research and technology being pursued and to the skill mix of the staff that makes it possible. At the time of publication, NASA Lewis was undergoing a name change to the NASA John H. Glenn Research Center at Lewis Field.

9. Credit JPL. Photographic copy of drawing, engineering drawing showing ...

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

9. Credit JPL. Photographic copy of drawing, engineering drawing showing structure of Test Stand 'A' (Building 4202/E-3) and its relationship to the Monitor Building or blockhouse (Building 4203/E-4) when a reinforced concrete machinery room was added to the west side of Test Stand 'A' in 1955. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering 'Electrical Layout - Muroc, Test Stand & Refrigeration Equipment Room,' drawing no. E3/7-0, April 6, 1955. - Jet Propulsion Laboratory Edwards Facility, Test Stand A, Edwards Air Force Base, Boron, Kern County, CA

On the critical flame radius and minimum ignition energy for spherical flame initiation

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

Chen, Zheng; Burke, M. P.; Ju, Yiguang

2011-01-01

Spherical flame initiation from an ignition kernel is studied theoretically and numerically using different fuel/oxygen/helium/argon mixtures (fuel: hydrogen, methane, and propane). The emphasis is placed on investigating the critical flame radius controlling spherical flame initiation and its correlation with the minimum ignition energy. It is found that the critical flame radius is different from the flame thickness and the flame ball radius and that their relationship depends strongly on the Lewis number. Three different flame regimes in terms of the Lewis number are observed and a new criterion for the critical flame radius is introduced. For mixtures with Lewis numbermore » larger than a critical Lewis number above unity, the critical flame radius is smaller than the flame ball radius but larger than the flame thickness. As a result, the minimum ignition energy can be substantially over-predicted (under-predicted) based on the flame ball radius (the flame thickness). The results also show that the minimum ignition energy for successful spherical flame initiation is proportional to the cube of the critical flame radius. Furthermore, preferential diffusion of heat and mass (i.e. the Lewis number effect) is found to play an important role in both spherical flame initiation and flame kernel evolution after ignition. It is shown that the critical flame radius and the minimum ignition energy increase significantly with the Lewis number. Therefore, for transportation fuels with large Lewis numbers, blending of small molecule fuels or thermal and catalytic cracking will significantly reduce the minimum ignition energy.« less

Lewis x is highly expressed in normal tissues: a comparative immunohistochemical study and literature revision.

PubMed

Croce, María V; Isla-Larrain, Marina; Rabassa, Martín E; Demichelis, Sandra; Colussi, Andrea G; Crespo, Marina; Lacunza, Ezequiel; Segal-Eiras, Amada

2007-01-01

An immunohistochemical analysis was employed to determine the expression of carbohydrate antigens associated to mucins in normal epithelia. Tissue samples were obtained as biopsies from normal breast (18), colon (35) and oral cavity mucosa (8). The following carbohydrate epitopes were studied: sialyl-Lewis x, Lewis x, Lewis y, Tn hapten, sialyl-Tn and Thomsen-Friedenreich antigen. Mucins were also studied employing antibodies against MUC1, MUC2, MUC4, MUC5AC, MUC6 and also normal colonic glycolipid. Statistical analysis was performed and Kendall correlations were obtained. Lewis x showed an apical pattern mainly at plasma membrane, although cytoplasmic staining was also found in most samples. TF, Tn and sTn haptens were detected in few specimens, while sLewis x was found in oral mucosa and breast tissue. Also, normal breast expressed MUC1 at a high percentage, whereas MUC4 was observed in a small number of samples. Colon specimens mainly expressed MUC2 and MUC1, while most oral mucosa samples expressed MUC4 and MUC1. A positive correlation between MUC1VNTR and TF epitope (r=0.396) was found in breast samples, while in colon specimens MUC2 and colonic glycolipid versus Lewis x were statistically significantly correlated (r=0.28 and r=0.29, respectively). As a conclusion, a defined carbohydrate epitope expression is not exclusive of normal tissue or a determined localization, and it is possible to assume that different glycoproteins and glycolipids may be carriers of carbohydrate antigens depending on the tissue localization considered.

Neurodegenerative disease concomitant proteinopathies are prevalent, age-related and APOE4-associated.

PubMed

Robinson, John L; Lee, Edward B; Xie, Sharon X; Rennert, Lior; Suh, EunRan; Bredenberg, Colin; Caswell, Carrie; Van Deerlin, Vivianna M; Yan, Ning; Yousef, Ahmed; Hurtig, Howard I; Siderowf, Andrew; Grossman, Murray; McMillan, Corey T; Miller, Bruce; Duda, John E; Irwin, David J; Wolk, David; Elman, Lauren; McCluskey, Leo; Chen-Plotkin, Alice; Weintraub, Daniel; Arnold, Steven E; Brettschneider, Johannes; Lee, Virginia M-Y; Trojanowski, John Q

2018-06-05

Lewy bodies commonly occur in Alzheimer's disease, and Alzheimer's disease pathology is frequent in Lewy body diseases, but the burden of co-pathologies across neurodegenerative diseases is unknown. We assessed the extent of tau, amyloid-β, α-synuclein and TDP-43 proteinopathies in 766 autopsied individuals representing a broad spectrum of clinical neurodegenerative disease. We interrogated pathological Alzheimer's disease (n = 247); other tauopathies (n = 95) including Pick's disease, corticobasal disease and progressive supranuclear palsy; the synucleinopathies (n = 164) including multiple system atrophy and Lewy body disease; the TDP-43 proteinopathies (n = 188) including frontotemporal lobar degeneration with TDP-43 inclusions and amyotrophic lateral sclerosis; and a minimal pathology group (n = 72). Each group was divided into subgroups without or with co-pathologies. Age and sex matched logistic regression models compared co-pathology prevalence between groups. Co-pathology prevalence was similar between the minimal pathology group and most neurodegenerative diseases for each proteinopathy: tau was nearly universal (92-100%), amyloid-β common (20-57%); α-synuclein less common (4-16%); and TDP-43 the rarest (0-16%). In several neurodegenerative diseases, co-pathology increased: in Alzheimer's disease, α-synuclein (41-55%) and TDP-43 (33-40%) increased; in progressive supranuclear palsy, α-synuclein increased (22%); in corticobasal disease, TDP-43 increased (24%); and in neocortical Lewy body disease, amyloid-β (80%) and TDP-43 (22%) increased. Total co-pathology prevalence varied across groups (27-68%), and was increased in high Alzheimer's disease, progressive supranuclear palsy, and neocortical Lewy body disease (70-81%). Increased age at death was observed in the minimal pathology group, amyotrophic lateral sclerosis, and multiple system atrophy cases with co-pathologies. In amyotrophic lateral sclerosis and neocortical Lewy body disease, co-pathologies associated with APOE ɛ4. Lewy body disease cases with Alzheimer's disease co-pathology had substantially lower Mini-Mental State Examination scores than pure Lewy body disease. Our data imply that increased age and APOE ɛ4 status are risk factors for co-pathologies independent of neurodegenerative disease; that neurodegenerative disease severity influences co-pathology as evidenced by the prevalence of co-pathology in high Alzheimer's disease and neocortical Lewy body disease, but not intermediate Alzheimer's disease or limbic Lewy body disease; and that tau and α-synuclein strains may also modify co-pathologies since tauopathies and synucleinopathies had differing co-pathologies and burdens. These findings have implications for clinical trials that focus on monotherapies targeting tau, amyloid-β, α-synuclein and TDP-43.

Photochemical Stereocontrol Using Tandem Photoredox–Chiral Lewis Acid Catalysis

PubMed Central

2016-01-01

Conspectus The physical, biological, and materials properties of organic compounds are determined by their three-dimensional molecular shape. The development of methods to dictate the stereochemistry of organic reactions has consequently emerged as one of the central themes of contemporary synthetic chemistry. Over the past several decades, chiral catalysts have been developed to control the enantioselectivity of almost every class of synthetically useful transformation. Photochemical reactions, however, are a conspicuous exception. Relatively few examples of highly enantioselective catalytic photoreactions have been reported to date, despite almost a century of research in this field. The development of robust strategies for photochemical enantiocontrol has thus proven to be a long-standing and surprisingly difficult challenge. For the past decade, our laboratory has been studying the application of transition metal photocatalysts to a variety of problems in synthetic organic chemistry. These efforts have recently culminated in the discovery of an effective system in which the activity of a visible light absorbing transition metal photoredox catalyst is combined with a second stereocontrolling chiral Lewis acid catalyst. This dual catalyst strategy has been applied to a diverse range of photochemical reactions; these have included highly enantioselective photocatalytic [2 + 2] cycloadditions, [3 + 2] cycloadditions, and radical conjugate addition reactions. This Account describes the development of the tandem Lewis acid photoredox catalysis strategy utilized in our laboratory. It provides an analysis of the factors that we believe to be particularly important to the success of this seemingly robust approach to photocatalytic stereocontrol. (1) The photocatalysts utilized in our systems are activated by wavelengths of visible light where the organic substrates are transparent, which minimizes the possibility of competitive racemic background photoreactions. (2) The high degree of tolerance that Ru(bpy)32+ and similar octahedral metal polypyridine complexes exhibit toward Lewis acids affords great flexibility in tuning the structure of the stereocontrolling chiral catalyst without perturbing the photoredox properties of the photocatalyst. (3) Synthetic chemists have amassed a substantial understanding of the features that are common in highly successful chiral Lewis acid catalyzed reactions, and these deep, well-validated insights are readily applied to the reactions of a variety of photogenerated intermediates. We hope that the recent success of this and similar dual catalytic systems will provide a useful foundation for the further development of powerful, stereocontrolled photochemical reactions. PMID:27505691

Photochemical Stereocontrol Using Tandem Photoredox-Chiral Lewis Acid Catalysis.

PubMed

Yoon, Tehshik P

2016-10-18

The physical, biological, and materials properties of organic compounds are determined by their three-dimensional molecular shape. The development of methods to dictate the stereochemistry of organic reactions has consequently emerged as one of the central themes of contemporary synthetic chemistry. Over the past several decades, chiral catalysts have been developed to control the enantioselectivity of almost every class of synthetically useful transformation. Photochemical reactions, however, are a conspicuous exception. Relatively few examples of highly enantioselective catalytic photoreactions have been reported to date, despite almost a century of research in this field. The development of robust strategies for photochemical enantiocontrol has thus proven to be a long-standing and surprisingly difficult challenge. For the past decade, our laboratory has been studying the application of transition metal photocatalysts to a variety of problems in synthetic organic chemistry. These efforts have recently culminated in the discovery of an effective system in which the activity of a visible light absorbing transition metal photoredox catalyst is combined with a second stereocontrolling chiral Lewis acid catalyst. This dual catalyst strategy has been applied to a diverse range of photochemical reactions; these have included highly enantioselective photocatalytic [2 + 2] cycloadditions, [3 + 2] cycloadditions, and radical conjugate addition reactions. This Account describes the development of the tandem Lewis acid photoredox catalysis strategy utilized in our laboratory. It provides an analysis of the factors that we believe to be particularly important to the success of this seemingly robust approach to photocatalytic stereocontrol. (1) The photocatalysts utilized in our systems are activated by wavelengths of visible light where the organic substrates are transparent, which minimizes the possibility of competitive racemic background photoreactions. (2) The high degree of tolerance that Ru(bpy) 3 2+ and similar octahedral metal polypyridine complexes exhibit toward Lewis acids affords great flexibility in tuning the structure of the stereocontrolling chiral catalyst without perturbing the photoredox properties of the photocatalyst. (3) Synthetic chemists have amassed a substantial understanding of the features that are common in highly successful chiral Lewis acid catalyzed reactions, and these deep, well-validated insights are readily applied to the reactions of a variety of photogenerated intermediates. We hope that the recent success of this and similar dual catalytic systems will provide a useful foundation for the further development of powerful, stereocontrolled photochemical reactions.

Conversion of glucose to sorbose

DOEpatents

Davis, Mark E.; Gounder, Rajamani

2016-02-09

The present invention is directed to methods for preparing sorbose from glucose, said method comprising: (a) contacting the glucose with a silica-containing structure comprising a zeolite having a topology of a 12 membered-ring or larger, an ordered mesoporous silica material, or an amorphous silica, said structure containing Lewis acidic Ti.sup.4+ or Zr.sup.4+ or both Ti.sup.4+ and Zr.sup.4+ framework centers, said contacting conducted under reaction conditions sufficient to isomerize the glucose to sorbose. The sorbose may be (b) separated or isolated; or (c) converted to ascorbic acid.

Probabilistic structural analysis to quantify uncertainties associated with turbopump blades

NASA Technical Reports Server (NTRS)

Nagpal, Vinod K.; Rubinstein, Robert; Chamis, Christos C.

1987-01-01

A probabilistic study of turbopump blades has been in progress at NASA Lewis Research Center for over the last two years. The objectives of this study are to evaluate the effects of uncertainties in geometry and material properties on the structural response of the turbopump blades to evaluate the tolerance limits on the design. A methodology based on probabilistic approach has been developed to quantify the effects of the random uncertainties. The results of this study indicate that only the variations in geometry have significant effects.

Stress Corrosion Testing

NASA Technical Reports Server (NTRS)

1985-01-01

Advanced testing of structural materials was developed by Lewis Research Center and Langley Research Center working with the American Society for Testing and Materials (ASTM). Under contract, Aluminum Company of America (Alcoa) conducted a study for evaluating stress corrosion cracking, and recommended the "breaking load" method which determines fracture strengths as well as measuring environmental degradation. Alcoa and Langley plan to submit the procedure to ASTM as a new testing method.

Laser-Induced Incandescence in Microgravity

NASA Technical Reports Server (NTRS)

VanderWal, Randall L.

1997-01-01

Microgravity offers unique opportunities for studying both soot growth and the effect of soot radiation upon flame structure and spread. LII has been characterized and developed at NASA-Lewis for soot volume fraction determination in a wide range of 1-g combustion applications. Reported here are the first demonstrations of LII performed in a microgravity environment. Examples are shown for laminar and turbulent gas-jet diffusion flames in 0-g.

Cooperative catalysis for the direct hydrodeoxygenation of vegetable oils into diesel-range alkanes over Pd/NbOPO4.

PubMed

Xia, Qineng; Zhuang, Xiaojing; Li, Molly Meng-Jung; Peng, Yung-Kang; Liu, Guoliang; Wu, Tai-Sing; Soo, Yun-Liang; Gong, Xue-Qing; Wang, Yanqin; Tsang, Shik Chi Edman

2016-04-14

Near quantitative carbon yields of diesel-range alkanes were achieved from the hydrodeoxygenation of triglycerides over Pd/NbOPO4 under mild conditions with no catalyst deactivation: catalyst characterization and theoretical calculations suggest that the high hydrodeoxygenation activity originated from the synergistic effect of Pd and strong Lewis acidity on the unique structure of NbOPO4.

At Last: "What's Discourse Got to Do with It?" A Meditation on Critical Discourse Analysis in Literacy Research

ERIC Educational Resources Information Center

Lewis, Cynthia

2006-01-01

Lewis explains why critical discourse analysis (CDA) has become an indispensable method for many researchers trying to understand how ideologies and social structures are reflected in and reified by language. The critical linguistic turn that has occurred in the humanities and social sciences for the last three decade has finally taken hold in the…

Aeropropulsion 1987

NASA Technical Reports Server (NTRS)

1990-01-01

Papers from the Aeropropulsion '87 Conference, held at the NASA Lewis Research Center (LeRC), are presented. Unclassified presentations by LeRC and NASA Headquarters senior management and many LeRC technical authors covered the philosophy and major directions of the LeRC aeropropulsion program, and presented a broad spectrum of recent research results in materials, structures, internal fluid mechanics, instrumentation and controls, and both subsonic and high-speed propulsion technology.

10. Photographic copy of photocopy of bridge drawing, half plans ...

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

10. Photographic copy of photocopy of bridge drawing, half plans and elevation (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 2 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

11. Photographic copy of photocopy of bridge drawing, half plans ...

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

11. Photographic copy of photocopy of bridge drawing, half plans and footings (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 3 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

Identifying and Assessing Self-Images in Drawings by Delinquent Adolescents (in 2 Parts).

ERIC Educational Resources Information Center

Silver, Rawley; Ellison, JoAnne

1995-01-01

Examines assumption that art therapists can objectively identify self-images in drawings by troubled adolescents without talking to these youth. Findings suggest that discussion, though preferable, is not required for identifying self-images. Analysis of adolescents' drawings indicates that structured art assessment can be useful in evaluating…

12. Photographic copy of photocopy of bridge drawing, half plans ...

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

12. Photographic copy of photocopy of bridge drawing, half plans and abutment elevation (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 4 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

9. Photographic copy of photocopy of bridge drawing, situation plan ...

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

9. Photographic copy of photocopy of bridge drawing, situation plan and profile on center line (June 12, 1937, original drawing on file in Structures Section, Utah Department of Transportation, Salt Lake City, Utah). SHEET NO. 1 OF 6 SHEETS. - Gould Wash Bridge, Spanning Gould Wash at State Route 9, Hurricane, Washington County, UT

A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini).

PubMed

Caterino, Michael S; Tishechkin, Alexey K

2013-01-01

Here we present a complete revision of the species of Baconia. Up until now there have been 27 species assigned to the genus (Mazur, 2011), in two subgenera (Binhister Cooman and Baconia s. str.), with species in the Neotropical, Nearctic, Palaearctic, and Oriental regions. We recognize all these species as valid and correctly assigned to the genus, and redescribe all of them. We synonymize Binhister, previously used for a polyphyletic assemblage of species with varied relationships in the genus. We move four species into Baconia from other genera, and describe 85 species as new, bringing the total for the genus to 116 species. We divide these into 12 informal species groups, leaving 13 species unplaced to group. We present keys and diagnoses for all species, as well as habitus photos and illustrations of male genitalia for nearly all. The genus now contains the following species and species groups: Baconia loricata group [Baconia loricata Lewis, 1885, B. patula Lewis, 1885, Baconia gounellei (Marseul, 1887a), Baconia jubaris (Lewis, 1901), Baconia festiva (Lewis, 1891), Baconia foliosoma sp. n., Baconia sapphirina sp. n., Baconia furtiva sp. n., Baconia pernix sp. n., Baconia applanatis sp. n., Baconia disciformis sp. n., Baconia nebulosa sp. n., Baconia brunnea sp. n.], Baconia godmani group [Baconia godmani (Lewis, 1888), Baconia venusta (J. E. LeConte, 1845), Baconia riehli (Marseul, 1862), comb. n., Baconia scintillans sp. n., Baconia isthmia sp. n., Baconia rossi sp. n., Baconia navarretei sp. n., Baconia maculata sp. n., Baconia deliberata sp. n., Baconia excelsa sp. n., Baconia violacea (Marseul, 1853), Baconia varicolor (Marseul, 1887b), Baconia dives (Marseul, 1862), Baconia eximia (Lewis, 1888), Baconia splendida sp. n., Baconia jacinta sp. n., Baconia prasina sp. n., Baconia opulenta sp. n., Baconia illustris (Lewis, 1900), Baconia choaspites (Lewis, 1901), Baconia lewisi Mazur, 1984], Baconia salobrus group [Baconia salobrus (Marseul, 1887b), Baconia turgifrons sp. n., Baconia crassa sp. n., Baconia anthracina sp. n., Baconia emarginata sp. n., Baconia obsoleta sp. n.], Baconia ruficauda group [Baconia ruficauda sp. n., Baconia repens sp. n.], Baconia angusta group [Baconia angusta Schmidt, 1893a, Baconia incognita sp. n., Baconia guartela sp. n., Baconia bullifrons sp. n., Baconia cavei sp. n., Baconia subtilis sp. n., Baconia dentipes sp. n., Baconia rubripennis sp. n., Baconia lunatifrons sp. n.], Baconia aeneomicans group [Baconia aeneomicans (Horn, 1873), Baconia pulchella sp. n., Baconia quercea sp. n., Baconia stephani sp. n., Baconia irinae sp. n., Baconia fornix sp. n., Baconia slipinskii Mazur, 1981, Baconia submetallica sp. n., Baconia diminua sp. n., Baconia rufescens sp. n., Baconia punctiventer sp. n., Baconia aulaea sp. n., Baconia mustax sp. n., Baconia plebeia sp. n., Baconia castanea sp. n., Baconia lescheni sp. n., Baconia oblonga sp. n., Baconia animata sp. n., Baconia teredina sp. n., Baconia chujoi (Cooman, 1941), Baconia barbarus (Cooman, 1934), Baconia reposita sp. n., Baconia kubani sp. n., Baconia wallacea sp. n., Baconia bigemina sp. n., Baconia adebratti sp. n., Baconia silvestris sp. n.], Baconia cylindrica group [Baconia cylindrica sp. n., Baconia chatzimanolisi sp. n.], Baconia gibbifer group [Baconia gibbifer sp. n., B. piluliformis sp. n., Baconia maquipucunae sp. n., Baconia tenuipes sp. n., Baconia tuberculifer sp. n., Baconia globosa sp. n.], Baconia insolita group [Baconia insolita (Schmidt, 1893a), comb. n., Baconia burmeisteri (Marseul, 1870), Baconia tricolor sp. n., Baconia pilicauda sp. n.], Baconia riouka group [Baconia riouka (Marseul, 1861), Baconia azuripennis sp. n.], Baconia famelica group [Baconia famelica sp. n., Baconia grossii sp. n., Baconia redemptor sp. n., Baconia fortis sp. n., Baconia longipes sp. n., Baconia katieae sp. n., Baconia cavifrons (Lewis, 1893), comb. n., Baconia haeterioides sp. n.], Baconia micans group [Baconia micans (Schmidt, 1889a), Baconia carinifrons sp. n., Baconia fulgida (Schmidt, 1889c)], Baconia incertae sedis [Baconia chilense (Redtenbacher, 1867), Baconia glauca (Marseul, 1884), Baconia coerulea (Bickhardt, 1917), Baconia angulifrons sp. n., Baconia sanguinea sp. n., Baconia viridimicans (Schmidt, 1893b), Baconia nayarita sp. n., Baconia viridis sp. n., Baconia purpurata sp. n., Baconia aenea sp. n., Baconia clemens sp. n., Baconia leivasi sp. n., Baconia atricolor sp. n.]. We designate lectotypes for the following species: Baconia loricata Lewis, 1885,Phelister gounellei Marseul, 1887, Baconia jubaris Lewis, 1901, Baconia festiva Lewis, 1891, Platysoma venustum J.E. LeConte, 1845, Phelister riehli Marseul, 1862, Phelister violaceus Marseul, 1853, Phelister varicolor Marseul, 1887b, Phelister illustris Lewis, 1900, Baconia choaspites Lewis, 1901, Epierus festivus Lewis, 1898, Phelister salobrus Marseul, 1887, Baconia angusta Schmidt, 1893a, Phelister insolitus Schmidt, 1893a, Pachycraerus burmeisteri Marseul, 1870, Phelister riouka Marseul, 1861, Homalopygus cavifrons Lewis, 1893, Phelister micans Schmidt, 1889a, Phelister coeruleus Bickhardt, 1917, and Phelister viridimicans Schmidt, 1893b. We designate neotypes for Baconia patula Lewis, 1885 and Hister aeneomicans Horn, 1873, whose type specimens are lost.

A systematic revision of Baconia Lewis (Coleoptera, Histeridae, Exosternini)

PubMed Central

Caterino, Michael S.; Tishechkin, Alexey K.

2013-01-01

Abstract Here we present a complete revision of the species of Baconia. Up until now there have been 27 species assigned to the genus (Mazur, 2011), in two subgenera (Binhister Cooman and Baconia s. str.), with species in the Neotropical, Nearctic, Palaearctic, and Oriental regions. We recognize all these species as valid and correctly assigned to the genus, and redescribe all of them. We synonymize Binhister, previously used for a polyphyletic assemblage of species with varied relationships in the genus. We move four species into Baconia from other genera, and describe 85 species as new, bringing the total for the genus to 116 species. We divide these into 12 informal species groups, leaving 13 species unplaced to group. We present keys and diagnoses for all species, as well as habitus photos and illustrations of male genitalia for nearly all. The genus now contains the following species and species groups: Baconia loricata group [Baconia loricata Lewis, 1885, B. patula Lewis, 1885, Baconia gounellei (Marseul, 1887a), Baconia jubaris (Lewis, 1901), Baconia festiva (Lewis, 1891), Baconia foliosoma sp. n., Baconia sapphirina sp. n., Baconia furtiva sp. n., Baconia pernix sp. n., Baconia applanatis sp. n., Baconia disciformis sp. n., Baconia nebulosa sp. n., Baconia brunnea sp. n.], Baconia godmani group [Baconia godmani (Lewis, 1888), Baconia venusta (J. E. LeConte, 1845), Baconia riehli (Marseul, 1862), comb. n., Baconia scintillans sp. n., Baconia isthmia sp. n., Baconia rossi sp. n., Baconia navarretei sp. n., Baconia maculata sp. n., Baconia deliberata sp. n., Baconia excelsa sp. n., Baconia violacea (Marseul, 1853), Baconia varicolor (Marseul, 1887b), Baconia dives (Marseul, 1862), Baconia eximia (Lewis, 1888), Baconia splendida sp. n., Baconia jacinta sp. n., Baconia prasina sp. n., Baconia opulenta sp. n., Baconia illustris (Lewis, 1900), Baconia choaspites (Lewis, 1901), Baconia lewisi Mazur, 1984], Baconia salobrus group [Baconia salobrus (Marseul, 1887b), Baconia turgifrons sp. n., Baconia crassa sp. n., Baconia anthracina sp. n., Baconia emarginata sp. n., Baconia obsoleta sp. n.], Baconia ruficauda group [Baconia ruficauda sp. n., Baconia repens sp. n.], Baconia angusta group [Baconia angusta Schmidt, 1893a, Baconia incognita sp. n., Baconia guartela sp. n., Baconia bullifrons sp. n., Baconia cavei sp. n., Baconia subtilis sp. n., Baconia dentipes sp. n., Baconia rubripennis sp. n., Baconia lunatifrons sp. n.], Baconia aeneomicans group [Baconia aeneomicans (Horn, 1873), Baconia pulchella sp. n., Baconia quercea sp. n., Baconia stephani sp. n., Baconia irinae sp. n., Baconia fornix sp. n., Baconia slipinskii Mazur, 1981, Baconia submetallica sp. n., Baconia diminua sp. n., Baconia rufescens sp. n., Baconia punctiventer sp. n., Baconia aulaea sp. n., Baconia mustax sp. n., Baconia plebeia sp. n., Baconia castanea sp. n., Baconia lescheni sp. n., Baconia oblonga sp. n., Baconia animata sp. n., Baconia teredina sp. n., Baconia chujoi (Cooman, 1941), Baconia barbarus (Cooman, 1934), Baconia reposita sp. n., Baconia kubani sp. n., Baconia wallacea sp. n., Baconia bigemina sp. n., Baconia adebratti sp. n., Baconia silvestris sp. n.], Baconia cylindrica group [Baconia cylindrica sp. n., Baconia chatzimanolisi sp. n.], Baconia gibbifer group [Baconia gibbifer sp. n., B. piluliformis sp. n., Baconia maquipucunae sp. n., Baconia tenuipes sp. n., Baconia tuberculifer sp. n., Baconia globosa sp. n.], Baconia insolita group [Baconia insolita (Schmidt, 1893a), comb. n., Baconia burmeisteri (Marseul, 1870), Baconia tricolor sp. n., Baconia pilicauda sp. n.], Baconia riouka group [Baconia riouka (Marseul, 1861), Baconia azuripennis sp. n.], Baconia famelica group [Baconia famelica sp. n., Baconia grossii sp. n., Baconia redemptor sp. n., Baconia fortis sp. n., Baconia longipes sp. n., Baconia katieae sp. n., Baconia cavifrons (Lewis, 1893), comb. n., Baconia haeterioides sp. n.], Baconia micans group [Baconia micans (Schmidt, 1889a), Baconia carinifrons sp. n., Baconia fulgida (Schmidt, 1889c)], Baconia incertae sedis [Baconia chilense (Redtenbacher, 1867), Baconia glauca (Marseul, 1884), Baconia coerulea (Bickhardt, 1917), Baconia angulifrons sp. n., Baconia sanguinea sp. n., Baconia viridimicans (Schmidt, 1893b), Baconia nayarita sp. n., Baconia viridis sp. n., Baconia purpurata sp. n., Baconia aenea sp. n., Baconia clemens sp. n., Baconia leivasi sp. n., Baconia atricolor sp. n.]. We designate lectotypes for the following species: Baconia loricata Lewis, 1885,Phelister gounellei Marseul, 1887, Baconia jubaris Lewis, 1901, Baconia festiva Lewis, 1891, Platysoma venustum J.E. LeConte, 1845, Phelister riehli Marseul, 1862, Phelister violaceus Marseul, 1853, Phelister varicolor Marseul, 1887b, Phelister illustris Lewis, 1900, Baconia choaspites Lewis, 1901, Epierus festivus Lewis, 1898, Phelister salobrus Marseul, 1887, Baconia angusta Schmidt, 1893a, Phelister insolitus Schmidt, 1893a, Pachycraerus burmeisteri Marseul, 1870, Phelister riouka Marseul, 1861, Homalopygus cavifrons Lewis, 1893, Phelister micans Schmidt, 1889a, Phelister coeruleus Bickhardt, 1917, and Phelister viridimicans Schmidt, 1893b. We designate neotypes for Baconia patula Lewis, 1885 and Hister aeneomicans Horn, 1873, whose type specimens are lost. PMID:24194656

An electromechanical actuation system for an expendable launch vehicle

NASA Technical Reports Server (NTRS)

Burrows, Linda M.; Roth, Mary Ellen

1992-01-01

A major effort at the NASA Lewis Research Center in recent years has been to develop electro-mechanical actuators (EMA's) to replace the hydraulic systems used for thrust vector control (TVC) on launch vehicles. This is an attempt ot overcome the inherent inefficiencies and costs associated with the existing hydraulic structures. General Dynamics Space Systems Division, under contract to NASA Lewis, is developing 18.6 kW (25 hp), 29.8 kW (40 hp), and 52.2 kW (70 hp) peak EMA systems to meet the power demands for TVC on a family of vehicles developed for the National Launch System. These systems utilize a pulse population modulated converter and field-oriented control scheme to obtain independent control of both the voltage and frequency. These techniques allow an induction motor to be operated at its maximum torque at all times. At NASA Lewis, we are building on this technology to develop our own in-house system capable of meeting the peak power requirements for an expendable launch vehicle (ELV) such as the Atlas. Our EMA will be capable of delivering 22.4 kW (30 hp) peak power with a nominal of 6.0 kW (8 hp). This system differs from the previous ones in two areas: (1) the use of advanced control methods, and (2) the incorporation of built-in-test. The advanced controls are essential for minimizing the controller size, while the built-in-test is necessary to enhance the system reliability and vehicle health monitoring. The ultimate goal of this program is to demonstrate an EMA which will be capable of self-test and easy integration into other projects. This paper will describe the effort underway at NASA Lewis to develop an EMA for an Atlas class ELV. An explanation will be given for each major technology block, and the status of each major technology block and the status of the overall program will be reported.

Fresh clouds: A parameterized updraft method for calculating cloud densities in one-dimensional models

NASA Astrophysics Data System (ADS)

Wong, Michael H.; Atreya, Sushil K.; Kuhn, William R.; Romani, Paul N.; Mihalka, Kristen M.

2015-01-01

Models of cloud condensation under thermodynamic equilibrium in planetary atmospheres are useful for several reasons. These equilibrium cloud condensation models (ECCMs) calculate the wet adiabatic lapse rate, determine saturation-limited mixing ratios of condensing species, calculate the stabilizing effect of latent heat release and molecular weight stratification, and locate cloud base levels. Many ECCMs trace their heritage to Lewis (Lewis, J.S. [1969]. Icarus 10, 365-378) and Weidenschilling and Lewis (Weidenschilling, S.J., Lewis, J.S. [1973]. Icarus 20, 465-476). Calculation of atmospheric structure and gas mixing ratios are correct in these models. We resolve errors affecting the cloud density calculation in these models by first calculating a cloud density rate: the change in cloud density with updraft length scale. The updraft length scale parameterizes the strength of the cloud-forming updraft, and converts the cloud density rate from the ECCM into cloud density. The method is validated by comparison with terrestrial cloud data. Our parameterized updraft method gives a first-order prediction of cloud densities in a “fresh” cloud, where condensation is the dominant microphysical process. Older evolved clouds may be better approximated by another 1-D method, the diffusive-precipitative Ackerman and Marley (Ackerman, A.S., Marley, M.S. [2001]. Astrophys. J. 556, 872-884) model, which represents a steady-state equilibrium between precipitation and condensation of vapor delivered by turbulent diffusion. We re-evaluate observed cloud densities in the Galileo Probe entry site (Ragent, B. et al. [1998]. J. Geophys. Res. 103, 22891-22910), and show that the upper and lower observed clouds at ∼0.5 and ∼3 bars are consistent with weak (cirrus-like) updrafts under conditions of saturated ammonia and water vapor, respectively. The densest observed cloud, near 1.3 bar, requires unexpectedly strong updraft conditions, or higher cloud density rates. The cloud density rate in this layer may be augmented by a composition with non-NH4SH components (possibly including adsorbed NH3).

Electric Car

NASA Technical Reports Server (NTRS)

1977-01-01

NASA's Lewis Research Center undertook research toward a practical, economical battery with higher energy density. Borrowing from space satellite battery technology, Lewis came up with a nickel-zinc battery that promises longer life and twice the range of the lead-acid counterpart. Lewis researchers fabricated a prototype battery and installed it in an Otis P-500 electric utility van, using only the battery space already available and allowing battery weight equal to that of the va's conventional lead-acid battery

Plans and status of the NASA-Lewis Research Center wind energy project

NASA Technical Reports Server (NTRS)

Thomas, R.; Puthoff, R.; Savino, J.; Johnson, W.

1975-01-01

Wind energy is investigated as a source of energy. The wind energy program that is managed by the NASA-Lewis Research Center is described. The Lewis Research Center's Wind Power Office, its organization, plans, and status are discussed. Major elements of the wind power project included are: an experimental 100 kW wind-turbine generator; first generation industry-built and user-operated wind turbine generators; and supporting research and technology tasks.

New hypersonic facility capability at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Haas, Jeffrey E.; Chamberlin, Roger; Dicus, John H.

1989-01-01

Four facility activities are underway at NASA Lewis Research Center to develop new hypersonic propulsion test capability. Two of these efforts consist of upgrades to existing operational facilities. The other two activities will reactivate facilities that have been in a standby condition for over 15 years. These four activities are discussed and the new test facilities NASA Lewis will have in place to support evolving high speed research programs are described.

Enantioselective photochemistry via Lewis acid catalyzed triplet energy transfer

PubMed Central

Blum, Travis R.; Miller, Zachary D.; Bates, Desiree M.; Guzei, Ilia A.; Yoon, Tehshik P.

2017-01-01

Relatively few catalytic systems are able to control the stereochemistry of electronically excited organic intermediates. Here we report the discovery that a chiral Lewis acid complex can catalyze triplet energy transfer from an electronically excited photosensitizer. This strategy is applied to asymmetric [2+2] photocycloadditions of 2′-hydroxychalcones using tris(bipyridyl) ruthenium(II) as a sensitizer. A variety of electrochemical, computational, and spectroscopic data rule out substrate activation via photoinduced electron transfer and instead support a mechanism in which Lewis acid coordination dramatically lowers the triplet energy of the chalcone substrate. We expect that this approach will enable chemists to more broadly apply their detailed understanding of chiral Lewis acid catalysis to stereocontrol in reactions of electronically excited states. PMID:27980203

Integrated support structure

NASA Technical Reports Server (NTRS)

Bruneau, Stephen D.; Campbell, John T.; Struven, Christopher A.

1990-01-01

This Major Qualifying Project is part of the Advanced Space Design Program at WPI. The goal is to design a support structure for a NASA GetAway Special experimental canister. The payload integration, weight, volume, and structural integrity of the canister as specified by NASA guidelines were studied. The end result is a complete set of design drawings with interface drawings and data to specify the design and leave a base on which the next group can concentrate.

Computer Program Re-layers Engineering Drawings

NASA Technical Reports Server (NTRS)

Crosby, Dewey C., III

1990-01-01

RULCHK computer program aids in structuring layers of information pertaining to part or assembly designed with software described in article "Software for Drawing Design Details Concurrently" (MFS-28444). Checks and optionally updates structure of layers for part. Enables designer to construct model and annotate its documentation without burden of manually layering part to conform to standards at design time.

Drawing-induced changes in morphology and mechanical properties of hornet silk gel films.

PubMed

Kameda, Tsunenori; Kojima, Katsura; Togawa, Eiji; Sezutsu, Hideki; Zhang, Qiang; Teramoto, Hidetoshi; Tamada, Yasushi

2010-04-12

Complete amino acid sequences of the four major proteins (Vssilk 1-4) of silk (hornet silk) obtained from yellow hornet ( Vespa simillima , Vespinae, Vespidae) cocoons have been determined. The native structure of the hornet silk (HS), in which Vssilk 1-4 have an alpha-helix domain with coiled-coil alpha-helices and a beta-sheet domain, is restored when hornet silk gel films (HSGFs) are formed by pressing and drying HS hydrogel. Necking occurs when dry HSGFs are drawn; however, wet HSGFs can be uniaxially drawn with a draw ratio (DR) of 2. Drawing helps obtain high-performance films with a maximum tensile strength and tensile modulus of 170 MPa and 5.5 GPa, respectively. Drawing-induced changes in the orientation and conformation of the coiled-coil structure are investigated.

Nitroxide stable radicals interacting as Lewis bases in hydrogen bonds: A search in the Cambridge structural data base for intermolecular contacts

NASA Astrophysics Data System (ADS)

Alkorta, Ibon; Elguero, José; Elguero, Eric

2017-11-01

1125 X-ray structures of nitroxide free radicals presenting intermolecular hydrogen bonds have been reported in the Cambridge Structural Database. We will report in this paper a qualitative and quantitative analysis of these bonds. The observation in some plots of an excluded region was statistically analyzed using convex hull and kernel smooting methodologies. A theoretical study at the MP2 level with different basis has been carried out indicating that the nitronyl nitroxide radicals (five electrons) lie just in between nitroso compounds (four electrons) and amine N-oxides (six electrons) as far as hydrogen-bond basicity is concerned.

Crystallography of rare galactic honeycomb structure near supernova 1987a

NASA Technical Reports Server (NTRS)

Noever, David A.

1994-01-01

Near supernova 1987a, the rare honeycomb structure of 20-30 galactic bubbles measures 30 x 90 light years. Its remarkable regularity in bubble size suggests a single-event origin which may correlate with the nearby supernova. To test the honeycomb's regularity in shape and size, the formalism of statistical crystallography is developed here for bubble sideness. The standard size-shape relations (Lewis's law, Desch's law, and Aboav-Weaire's law) govern area, perimeter and nearest neighbor shapes. Taken together, they predict a highly non-equilibrium structure for the galactic honeycomb which evolves as a bimodal shape distribution without dominant bubble perimeter energy.

Langerhans' cell expression of the selectin ligand, sialyl Lewis x.

PubMed Central

Ross, E L; Barker, J N; Allen, M H; Chu, A C; Groves, R W; MacDonald, D M

1994-01-01

Cellular adhesion molecules play a central role in leucocyte migration through peripheral blood and tissues. A crucial stage in these events in selectin-mediated adhesion involving E-selectin expressed on activated endothelium interacting with a range of carbohydrate ligands expressed by specific subpopulations of leucocytes. As such mechanisms may be relevant to bone marrow-derived dendritic epidermal Langerhans' cell (LC) migration, expression of these carbohydrate ligands was assessed immunocytochemically in whole skin biopsies and in epidermal cell suspensions obtained from adult humans. Double-labelling experiments revealed that sialyl Lewis x, recognized by the monoclonal antibody CSLEX1, was expressed on epidermal LC (n = 9). Furthermore, expression was enhanced at 24 hr following epicutaneous application of antigen and in the inflammatory disorder psoriasis (n = 10). E-selectin was concomitantly strongly expressed on dermal endothelium in psoriasis and allergic contact dermatitis. Intradermal injection of the T-cell-derived cytokine interferon-gamma (IFN-gamma) led to increased LC expression of sialyl Lewis x. In epidermal cell suspensions, in contrast to keratinocytes, CD1a+ cells expressed sialyl Lewis x, intensity of which was enhanced after 4 days in culture. CSLEX1 staining could be abolished and CD15 (non-sialated Lewis x) expression induced by saponification and treatment with neuraminidase. Expression of other selectin ligands was also examined. While the cutaneous lymphocyte antigen defined by the monoclonal antibody HECA-452 reacted with a small minority of LC, sialyl Lewis a and sulphatide were not expressed under any experimental conditions. These studies indicate that E-selectin-sialyl Lewis x interactions are potentially important in LC migration, both into and out of skin. Images Figure 2 Figure 3 Figure 5 Figure 6 PMID:7512530

6. Photographic copy of original construction drawing, no date, from ...

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

6. Photographic copy of original construction drawing, no date, from files in the Office of the Chief Engineer, U.S. Fish and Wildlife Service Regional Office, Denver. GATE CONTROL STRUCTURE (generic drawing used for all five dams in refuge) - J. Clark Salyer National Wildlife Refuge Dams, Along Lower Souris River, Kramer, Bottineau County, ND

Social Interactions and Familial Relationships Preservice Science Teachers Describe during Interviews about Their Drawings of the Endocrine and Gastrointestinal Systems

ERIC Educational Resources Information Center

Patrick, Patricia

2014-01-01

This study examined preservice science teachers' understandings of the structure and function of the human gastrointestinal and endocrine systems through drawings and interviews. Moreover, the preservice science teachers described where they thought they learned about the systems. The 142 preservice teachers were asked to draw the human…

Solar Mirror Fabrication in the Technical Services Building

NASA Image and Video Library

1966-02-21

Daniel Bernatowicz, Chief of the Advanced Power Systems Branch at the National Aeronautics and Space Administration (NASA) Lewis Research Center, examines a 20-foot section of a solar mirror being fabricated in the Jig Bore Room of the Technical Services Building. NASA Lewis was conducting a wide-ranging effort to explore methods of generating electrical power for spacecraft. One method employed a large parabolic mirror to concentrate the sun’s energy. The mirror had to remain rigid and withstand micrometeoroids, but remain light and compact enough to be easily launched. In 1963 Bernatowicz and his researchers undertook a program to design a solar mirror to work with the Brayton cycle system on a space station. The mirror in this photograph was prepared for a conference on Advanced Technology in Space Power Systems held at Lewis in late August 1966. Lewis experts discussed advances with batteries, fuel cells, isotope and thermoelectric generators, and the SNAP-8 space power system. Lewis was developing several types of solar mirrors to work with a Brayton cycle electric generating system. The mirror’s 12 sections were shaped using a unique forming process developed at Lewis, coated with an epoxy, and plated with aluminum. The mirror concentrated the Sun's rays on a heat storage receiver containing lithium fluoride. This material was heated to produce power in a turbogenerator system, while additional heat was stored for use when the unit was in the Earth's shadow.

Effects of Lewis number on the statistics of the invariants of the velocity gradient tensor and local flow topologies in turbulent premixed flames

NASA Astrophysics Data System (ADS)

Wacks, Daniel; Konstantinou, Ilias; Chakraborty, Nilanjan

2018-04-01

The behaviours of the three invariants of the velocity gradient tensor and the resultant local flow topologies in turbulent premixed flames have been analysed using three-dimensional direct numerical simulation data for different values of the characteristic Lewis number ranging from 0.34 to 1.2. The results have been analysed to reveal the statistical behaviours of the invariants and the flow topologies conditional upon the reaction progress variable. The behaviours of the invariants have been explained in terms of the relative strengths of the thermal and mass diffusions, embodied by the influence of the Lewis number on turbulent premixed combustion. Similarly, the behaviours of the flow topologies have been explained in terms not only of the Lewis number but also of the likelihood of the occurrence of individual flow topologies in the different flame regions. Furthermore, the sensitivity of the joint probability density function of the second and third invariants and the joint probability density functions of the mean and Gaussian curvatures to the variation in Lewis number have similarly been examined. Finally, the dependences of the scalar-turbulence interaction term on augmented heat release and of the vortex-stretching term on flame-induced turbulence have been explained in terms of the Lewis number, flow topology and reaction progress variable.

Effects of Lewis number on the statistics of the invariants of the velocity gradient tensor and local flow topologies in turbulent premixed flames

PubMed Central

Konstantinou, Ilias; Chakraborty, Nilanjan

2018-01-01

The behaviours of the three invariants of the velocity gradient tensor and the resultant local flow topologies in turbulent premixed flames have been analysed using three-dimensional direct numerical simulation data for different values of the characteristic Lewis number ranging from 0.34 to 1.2. The results have been analysed to reveal the statistical behaviours of the invariants and the flow topologies conditional upon the reaction progress variable. The behaviours of the invariants have been explained in terms of the relative strengths of the thermal and mass diffusions, embodied by the influence of the Lewis number on turbulent premixed combustion. Similarly, the behaviours of the flow topologies have been explained in terms not only of the Lewis number but also of the likelihood of the occurrence of individual flow topologies in the different flame regions. Furthermore, the sensitivity of the joint probability density function of the second and third invariants and the joint probability density functions of the mean and Gaussian curvatures to the variation in Lewis number have similarly been examined. Finally, the dependences of the scalar--turbulence interaction term on augmented heat release and of the vortex-stretching term on flame-induced turbulence have been explained in terms of the Lewis number, flow topology and reaction progress variable. PMID:29740257

Entrance to the NACA's Flight Propulsion Research Laboratory

NASA Image and Video Library

1948-08-21

The sign near the entrance of the National Advisory Committee for Aeronautics (NACA) Flight Propulsion Research Laboratory. The name was changed several weeks later to the Lewis Flight Propulsion Laboratory in honor of the NACA’s former Director of Aeronautical Research, George W. Lewis. The research laboratory has had five different names since its inception in 1941. The Cleveland laboratory was originally known as the NACA Aircraft Engine Research Laboratory. In 1947 it was renamed the NACA Flight Propulsion Research Laboratory to reflect the expansion of the research activities beyond just engines. Following the death of George Lewis, the name was changed to the NACA Lewis Flight Propulsion Laboratory in September 1948. On October 1, 1958, the lab was incorporated into the new NASA space agency, and it was renamed the NASA Lewis Research Center. Following John Glenn’s flight on the space shuttle, the name was changed again to the NASA Glenn Research Center on March 1, 1999. From his office in Washington DC, George Lewis managed the aeronautical research conducted at the NACA for over 20 years. His most important accomplishment, however, may have been an investigative tour of German research facilities in the fall of 1936. The visit resulted in the broadening of the scope of the NACA’s research and the physical expansion that included the new engine laboratory in Cleveland.

Memantine for Lewy body disorders: systematic review and meta-analysis.

PubMed

Matsunaga, Shinji; Kishi, Taro; Iwata, Nakao

2015-04-01

To clarify whether memantine is more efficacious in several outcomes and safer than placebo in patients with Lewy body disorders, we performed a meta-analysis of memantine in patients with Lewy body disorders. The meta-analysis included randomized controlled trials of memantine for Lewy body disorders in all patients with Lewy body disorders. Motor function, activities of daily living, Neuropsychiatric Inventory, Mini-Mental State Exam, discontinuation rate, and individual side effects were evaluated. No significant effects of memantine on motor function scores, Mini-Mental State Exam scores, Neuropsychiatric Inventory scores, and activity of daily living scores were found. However, memantine was superior to placebo in Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change scores (standardized mean difference: -0.26; 95% confidence interval: -0.51 to -0.02; z = 2.08; p = 0.04; two studies; N = 258). Dropout due to all causes, inefficacy, or adverse events were similar in both groups. Moreover, no significant differences in serious adverse events, somnolence/tiredness, stroke, dizziness/vertigo, and confusion were found between the groups. Our results suggest that memantine did not have a benefit for the treatment of Lewy body disorders in cognition and motor function. However, memantine may be superior to placebo for the overall impression of the disorders. Further, memantine is well tolerated. Copyright © 2015 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

7. This photographic copy of an engineering drawing displays the ...

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

7. This photographic copy of an engineering drawing displays the building's floor plan in its 1995 arrangement, with rooms designated. California Institute of Technology, Jet Propulsion Laboratory, Facilities Engineering and Construction Office, "Addition to Weigh & Control Bldg. E-35, Demolition, Floor and Roof Plans," drawing no. E35/3-0, October 5, 1983. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering: engineering drawings of structures at JPL Edwards Facility. Drawings on file at JPL Plant Engineering, Pasadena, California. - Jet Propulsion Laboratory Edwards Facility, Weigh & Control Building, Edwards Air Force Base, Boron, Kern County, CA

4. This photographic copy of an engineering drawing shows the ...

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

4. This photographic copy of an engineering drawing shows the plan and details for Test Stand "G" and the placement of the vibrator. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering: "Vibration Test Facility-Bldg E-72, Floor & Roof Plans, Sections, Details & Door Schedule," drawing no. E72/2-5, 21 May 1964. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering: engineering drawings of structures at JPL Edwards Facility. Drawings on file at JPL Plant Engineering, Pasadena, California. - Jet Propulsion Laboratory Edwards Facility, Test Stand G, Edwards Air Force Base, Boron, Kern County, CA

Rocket Propellant Talk at the 1957 NACA Lewis Inspection

NASA Image and Video Library

1957-10-21

A researcher works a demonstration board in the Rocket Engine Test Facility during the 1957 Inspection of the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory in Cleveland, Ohio. Representatives from the military, aeronautical industry, universities, and the press were invited to the laboratory to be briefed on the NACA’s latest research efforts and tour the test facilities. Over 1700 people visited the Lewis during the October 7-10, 1957 Inspection. The Soviet Union launched their first Sputnik satellite just days before on October 4. NACA Lewis had been involved in small rockets and propellants research since 1945, but the NACA leadership was wary of involving itself too deeply with the work since ballistics traditionally fell under the military’s purview. The Lewis research was performed by the High Temperature Combustion section in the Fuels and Lubricants Division in a series of small cinderblock test cells. The rocket group was expanded in 1952 and made several test runs in late 1954 using liquid hydrogen as a propellant. A larger test facility, the Rocket Engine Test Facility, was approved and became operational just in time for the Inspection.

Cholinesterase Inhibitors for Lewy Body Disorders: A Meta-Analysis

PubMed Central

Yasue, Ichiro; Iwata, Nakao

2016-01-01

Background: We performed a meta-analysis of cholinesterase inhibitors for patients with Lewy body disorders, such as Parkinson’s disease, Parkinson’s disease dementia, and dementia with Lewy bodies. Methods: The meta-analysis included only randomized controlled trials of cholinesterase inhibitors for Lewy body disorders. Results: Seventeen studies (n = 1798) were assessed. Cholinesterase inhibitors significantly improved cognitive function (standardized mean difference [SMD] = −0.53], behavioral disturbances (SMD = −0.28), activities of daily living (SMD = −0.28), and global function (SMD = −0.52) compared with control treatments. Changes in motor function were not significantly different from control treatments. Furthermore, the cholinesterase inhibitor group had a higher all-cause discontinuation (risk ratio [RR] = 1.48, number needed to harm [NNH] = 14), discontinuation due to adverse events (RR = 1.59, NNH = 20), at least one adverse event (RR = 1.13, NNH = 11), nausea (RR = 2.50, NNH = 13), and tremor (RR = 2.30, NNH = 20). Conclusions: Cholinesterase inhibitors appear beneficial for the treatment of Lewy body disorders without detrimental effects on motor function. However, a careful monitoring of treatment compliance and side effects is required. PMID:26221005

Microgravity Combustion Science: 1995 Program Update

NASA Technical Reports Server (NTRS)

Ross, Howard D. (Editor); Gokoglu, Suleyman A. (Editor); Friedman, Robert (Editor)

1995-01-01

Microgravity greatly benefits the study of fundamental combustion processes. In this environment, buoyancy-induced flow is nearly eliminated, weak or normally obscured forces and flows can be isolated, gravitational settling or sedimentation is nearly eliminated, and temporal and spatial scales can be expanded. This document reviews the state of knowledge in microgravity combustion science with the emphasis on NASA-sponsored developments in the current period of 1992 to early 1995. The subjects cover basic research in gaseous premixed and diffusion-flame systems, flame structure and sooting, liquid droplets and pools, and solid-surface ignition and flame spread. They also cover applied research in combustion synthesis of ceramic-metal composites, advanced diagnostic instrumentation, and on-orbit fire safety. The review promotes continuing research by describing the opportunities for Principal Investigator participation through the NASA Research Announcement program and the available NASA Lewis Research Center ground-based facilities and spaceflight accommodations. This review is compiled by the members and associates of the NASA Lewis Microgravity Combustion Branch, and it serves as an update of two previous overview reports.

Lewis acid-base interactions in weakly bound formaldehyde complexes with CO2, HCN, and FCN: considerations on the cooperative H-bonding effects.

PubMed

Rivelino, Roberto

2008-01-17

Ab initio quantum chemistry calculations reveal that HCN and mainly FCN can form Lewis acid-base complexes with formaldehyde associated with cooperative H bonds, as first noticed by Wallen et al. (Blatchford, M. A.; Raveendran, P.; Wallen, S. L. J. Am. Chem. Soc. 2002, 124, 14818-14819) for CO2-philic materials under supercritical conditions. The present results, obtained with MP2(Full)/aug-cc-pVDZ calculations, show that the degeneracy of the nu(2) mode in free HCN or FCN is removed upon complexation in the same fashion as that of CO2. The splitting of these bands along with the electron structure analysis provides substantial evidence of the interaction of electron lone pairs of the carbonyl oxygen with the electron-deficient carbon atom of the cyanides. Also, this work investigates the role of H bonds acting as additional stabilizing interactions in the complexes by performing the energetic and geometric characterization.

A vital sugar code for ricin toxicity.

PubMed

Taubenschmid, Jasmin; Stadlmann, Johannes; Jost, Markus; Klokk, Tove Irene; Rillahan, Cory D; Leibbrandt, Andreas; Mechtler, Karl; Paulson, James C; Jude, Julian; Zuber, Johannes; Sandvig, Kirsten; Elling, Ulrich; Marquardt, Thorsten; Thiel, Christian; Koerner, Christian; Penninger, Josef M

2017-11-01

Ricin is one of the most feared bioweapons in the world due to its extreme toxicity and easy access. Since no antidote exists, it is of paramount importance to identify the pathways underlying ricin toxicity. Here, we demonstrate that the Golgi GDP-fucose transporter Slc35c1 and fucosyltransferase Fut9 are key regulators of ricin toxicity. Genetic and pharmacological inhibition of fucosylation renders diverse cell types resistant to ricin via deregulated intracellular trafficking. Importantly, cells from a patient with SLC35C1 deficiency are also resistant to ricin. Mechanistically, we confirm that reduced fucosylation leads to increased sialylation of Lewis X structures and thus masking of ricin-binding sites. Inactivation of the sialyltransferase responsible for modifications of Lewis X (St3Gal4) increases the sensitivity of cells to ricin, whereas its overexpression renders cells more resistant to the toxin. Thus, we have provided unprecedented insights into an evolutionary conserved modular sugar code that can be manipulated to control ricin toxicity.

A vital sugar code for ricin toxicity

PubMed Central

Taubenschmid, Jasmin; Stadlmann, Johannes; Jost, Markus; Klokk, Tove Irene; Rillahan, Cory D; Leibbrandt, Andreas; Mechtler, Karl; Paulson, James C; Jude, Julian; Zuber, Johannes; Sandvig, Kirsten; Elling, Ulrich; Marquardt, Thorsten; Thiel, Christian; Koerner, Christian; Penninger, Josef M

2017-01-01

Ricin is one of the most feared bioweapons in the world due to its extreme toxicity and easy access. Since no antidote exists, it is of paramount importance to identify the pathways underlying ricin toxicity. Here, we demonstrate that the Golgi GDP-fucose transporter Slc35c1 and fucosyltransferase Fut9 are key regulators of ricin toxicity. Genetic and pharmacological inhibition of fucosylation renders diverse cell types resistant to ricin via deregulated intracellular trafficking. Importantly, cells from a patient with SLC35C1 deficiency are also resistant to ricin. Mechanistically, we confirm that reduced fucosylation leads to increased sialylation of Lewis X structures and thus masking of ricin-binding sites. Inactivation of the sialyltransferase responsible for modifications of Lewis X (St3Gal4) increases the sensitivity of cells to ricin, whereas its overexpression renders cells more resistant to the toxin. Thus, we have provided unprecedented insights into an evolutionary conserved modular sugar code that can be manipulated to control ricin toxicity. PMID:28925387

Is It Lewy Body Dementia or Something Else?

MedlinePlus

... personality and behavior, such as inappropriate or compulsive behavior, euphoria, apathy, decline in personal ... Road S.W., Lilburn, GA 30047 © 2018 Lewy Body Dementia Association, Inc. Connect ...

On the behaviour of biradicaloid [P(μ-NTer)]2 towards Lewis acids and bases.

PubMed

Hinz, Alexander; Schulz, Axel; Villinger, Alexander

2016-05-07

The well-known diphosphadiazane-1,3-diyl [P(μ-NTer)]2 (Ter = 2,6-bis(2,4,6-trimethyl-phenyl)-phenyl) was treated with Lewis bases such as N-heterocyclic carbenes and Lewis acids e.g. gold(i) chloride complexes. In the reaction with the Lewis base, fragmentation of the P2N2 framework was observed, yielding a salt of the type [(NHC)2P](+)[(TerN)2P](-) in a clean reaction. The reaction of [P(μ-NTer)]2 with gold(i) chloride afforded 1 : 1 and 1 : 2 complexes. The dinuclear complex [(ClAu)2P(μ-NTer)2P] displays a bridging P atom between both gold centers, as has been observed for P based zwitterions.

A Knowledge-Based System for Display and Prediction of O-Glycosylation Network Behaviour in Response to Enzyme Knockouts

PubMed Central

McDonald, Andrew G.; Tipton, Keith F.; Davey, Gavin P.

2016-01-01

O-linked glycosylation is an important post-translational modification of mucin-type protein, changes to which are important biomarkers of cancer. For this study of the enzymes of O-glycosylation, we developed a shorthand notation for representing GalNAc-linked oligosaccharides, a method for their graphical interpretation, and a pattern-matching algorithm that generates networks of enzyme-catalysed reactions. Software for generating glycans from the enzyme activities is presented, and is also available online. The degree distributions of the resulting enzyme-reaction networks were found to be Poisson in nature. Simple graph-theoretic measures were used to characterise the resulting reaction networks. From a study of in-silico single-enzyme knockouts of each of 25 enzymes known to be involved in mucin O-glycan biosynthesis, six of them, β-1,4-galactosyltransferase (β4Gal-T4), four glycosyltransferases and one sulfotransferase, play the dominant role in determining O-glycan heterogeneity. In the absence of β4Gal-T4, all Lewis X, sialyl-Lewis X, Lewis Y and Sda/Cad glycoforms were eliminated, in contrast to knockouts of the N-acetylglucosaminyltransferases, which did not affect the relative abundances of O-glycans expressing these epitopes. A set of 244 experimentally determined mucin-type O-glycans obtained from the literature was used to validate the method, which was able to predict up to 98% of the most common structures obtained from human and engineered CHO cell glycoforms. PMID:27054587

Surface characterization of acidic ceria-zirconia prepared by direct sulfation

NASA Astrophysics Data System (ADS)

Azambre, B.; Zenboury, L.; Weber, J. V.; Burg, P.

2010-05-01

Acidic ceria-zirconia (SCZ) solid acid catalysts with a nominal surface density of ca 2 SO 42-/nm 2 were prepared by a simple route consisting in soaking high specific surface area Ce xZr 1- xO 2 (with x = 0.21 and 0.69) mixed oxides solutions in 0.5 M sulphuric acid. Characterizations by TPD-MS, TP-DRIFTS and FT-Raman revealed that most of surface structures generated by sulfation are stable at least up to 700 °C under inert atmosphere and consist mainly as isolated sulfates located on defects or crystal planes and to a lesser extent as polysulfates. Investigations by pyridine adsorption/desorption have stated that: SCZ possess both strong Brønsted (B) and Lewis (L) acid sites, some of them being presumably superacidic; the B/L site ratio was found to be more dependent on the temperature and hydration degree than on the composition of the ceria-zirconia. By contrast, the reactivity of the parent Ce xZr 1- xO 2 materials towards pyridine is mostly driven by redox properties resulting in the formation of Py-oxide with the participation of Lewis acid sites of moderate strength ( cus Ce x+ and Zr x+ cations). Basicity studies by CO 2 adsorption/desorption reveal that SCZ surfaces are solely acidic whereas the number and strength of Lewis basic sites increases with the Ce content for the parent Ce xZr 1- xO 2 materials.

Studies of Premixed Laminar and Turbulent Flames at Microgravity

NASA Technical Reports Server (NTRS)

Ronney, Paul D.

1993-01-01

The work of the Principal Investigator (PI) has encompassed four topics related to the experimental and theoretical study of combustion limits in premixed flames at microgravity, as discussed in the following sections. These topics include: (1) radiation effects on premixed gas flames; (2) flame structure and stability at low Lewis number; (3) flame propagation and extinction is cylindrical tubes; and (4) experimental simulation of combustion processes using autocatalytic chemical reactions.

Hyper-Assembly of Self-Assembled Glycoclusters Mediated by Specific Carbohydrate-Carbohydrate Interactions.

PubMed

Yan, Gengwei; Yamaguchi, Takumi; Suzuki, Tatsuya; Yanaka, Saeko; Sato, Sota; Fujita, Makoto; Kato, Koichi

2017-05-04

Hybridization of a self-assembled, spherical complex with oligosaccharides containing Lewis X, a functional trisaccharide displayed on various cell surfaces, yielded well-defined glycoclusters. The self-assembled glycoclusters exhibited homophilic hyper-assembly in aqueous solution in a Ca 2+ -dependent manner through specific carbohydrate-carbohydrate interactions, offering a structural scaffold for functional biomimetic systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Environmental and High-Strain Rate effects on composites for engine applications

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Smith, G. T.

1982-01-01

The Lewis Research Center is conducting a series of programs intended to investigate and develop the application of composite materials to structural components for turbojet engines. A significant part of that effort is directed to establishing resistance, defect growth, and strain rate characteristics of composite materials over the wide range of environmental and load conditions found in commercial turbojet engine operations. Both analytical and experimental efforts are involved.

A forest transect of pine mountain, Kentucky: changes since E. Lucy Braun and chestnut blight

Treesearch

Tracy S. Hawkins

2006-01-01

In 1997, forest composition and structure were determined for Hi Lewis Pine Barrens State Nature Preserve, a 68-ha tract on the south slope of Pine Mountain, Harlan County, Kentucky. Data collected from 28 0.04-ha plots were used to delineate forest types. Percent canopy compositions were compared with those reported by Dr. E. Lucy Braun prior to the peak of chestnut...

Experimental and theoretical studies of the products of reaction between Ln(hfa) 3 and Cu(acac) 2 (Ln = La, Y; acac = acetylacetonate, hfa = hexafluoroacetylacetonate)

NASA Astrophysics Data System (ADS)

Rogachev, Andrey Yu.; Mironov, Andrey V.; Nemukhin, Alexander V.

2007-04-01

The new unusual heterobimetallic complex [La(hfa) 3Cu(acac) 2(H 2O)] ( I) was obtained in the reaction La(hfa) 3·2H 2O with Cu(acac) 2 in CHCl 3. This is the first example of such type of heterobimetallic complexes based on the Cu(acac) 2 species. According to the X-ray single crystal analysis, complex I crystallizes in the monoclinic space group P2 1/c, with a = 12.516(3) Å, b = 17.757(4) Å, c = 17.446(4) Å, β = 93.90(3)° and Z = 4. The structure consists of isolated heterobinuclear molecules with the coordination number of La being 9. The molecules are further assembled into dimers via hydrogen bonds. The theoretical modeling of the structure and the properties of parent monometallic complexes Ln(hfa) 3 (Ln = La, Y) and Cu(acac) 2 is described. The comparative theoretical study of lanthanide complexes indicates relations in formation of a heterobimetallic complex to the Lewis acidity of original monometallic complexes. In particular, the Lewis acidity and charge of the central metal ion in Ln(hfa) 3 are the key parameters accounting for the formation of [Ln(hfa) 3Cu(acac) 2].

Mechanistic Basis for High Stereoselectivity and Broad Substrate Scope in the (salen)Co(III)-Catalyzed Hydrolytic Kinetic Resolution

PubMed Central

Ford, David D.; Nielsen, Lars P. C.; Zuend, Stephan J.; Jacobsen, Eric N.

2013-01-01

In the (salen)Co(III)-catalyzed hydrolytic kinetic resolution (HKR) of terminal epoxides, the rate- and stereoselectivity-determining epoxide ring-opening step occurs by a cooperative bimetallic mechanism with one Co(III) complex acting as a Lewis acid and another serving to deliver the hydroxide nucleophile. In this paper, we analyze the basis for the extraordinarily high stereoselectivity and broad substrate scope observed in the HKR. We demonstrate that the stereochemistry of each of the two (salen)Co(III) complexes in the rate-determining transition structure is important for productive catalysis: a measurable rate of hydrolysis occurs only if the absolute stereochemistry of each of these (salen)Co(III) complexes is the same. Experimental and computational studies provide strong evidence that stereochemical communication in the HKR is mediated by the stepped conformation of the salen ligand, and not the shape of the chiral diamine backbone of the ligand. A detailed computational analysis reveals that the epoxide binds the Lewis acidic Co(III) complex in a well-defined geometry imposed by stereoelectronic, rather than steric effects. This insight serves as the basis of a complete stereochemical and transition structure model that sheds light on the reasons for the broad substrate generality of the HKR. PMID:24041239

Mechanistic basis for high stereoselectivity and broad substrate scope in the (salen)Co(III)-catalyzed hydrolytic kinetic resolution.

PubMed

Ford, David D; Nielsen, Lars P C; Zuend, Stephan J; Musgrave, Charles B; Jacobsen, Eric N

2013-10-16

In the (salen)Co(III)-catalyzed hydrolytic kinetic resolution (HKR) of terminal epoxides, the rate- and stereoselectivity-determining epoxide ring-opening step occurs by a cooperative bimetallic mechanism with one Co(III) complex acting as a Lewis acid and another serving to deliver the hydroxide nucleophile. In this paper, we analyze the basis for the extraordinarily high stereoselectivity and broad substrate scope observed in the HKR. We demonstrate that the stereochemistry of each of the two (salen)Co(III) complexes in the rate-determining transition structure is important for productive catalysis: a measurable rate of hydrolysis occurs only if the absolute stereochemistry of each of these (salen)Co(III) complexes is the same. Experimental and computational studies provide strong evidence that stereochemical communication in the HKR is mediated by the stepped conformation of the salen ligand, and not the shape of the chiral diamine backbone of the ligand. A detailed computational analysis reveals that the epoxide binds the Lewis acidic Co(III) complex in a well-defined geometry imposed by stereoelectronic rather than steric effects. This insight serves as the basis of a complete stereochemical and transition structure model that sheds light on the reasons for the broad substrate generality of the HKR.

Lewy Body Dementia

MedlinePlus

... People with Lewy body dementia may experience visual hallucinations, and changes in alertness and attention. Other effects ... body dementia signs and symptoms may include: Visual hallucinations. Hallucinations may be one of the first symptoms, ...

Lewis hybrid computing system, users manual

NASA Technical Reports Server (NTRS)

Bruton, W. M.; Cwynar, D. S.

1979-01-01

The Lewis Research Center's Hybrid Simulation Lab contains a collection of analog, digital, and hybrid (combined analog and digital) computing equipment suitable for the dynamic simulation and analysis of complex systems. This report is intended as a guide to users of these computing systems. The report describes the available equipment' and outlines procedures for its use. Particular is given to the operation of the PACER 100 digital processor. System software to accomplish the usual digital tasks such as compiling, editing, etc. and Lewis-developed special purpose software are described.

Addressing Uncertainty in Signal Propagation and Sensor Performance Predictions

DTIC Science & Technology

2008-11-01

Army Engineer Research and Develop- ment Center (ERDC) AT42 work package Environmental Awareness for Sensor Employment (EASE). M. S. Lewis is an Oak...L. Pettit, Sean Mackay, Matthew S. Lewis , and Peter M. Seman November 2008 C ol d R eg io n s R es ea rc h an d E n gi n ee ri n g La b...Propagation and Sensor Performance Predictions D. Keith Wilson, Matthew S. Lewis , and Peter M. Seman Cold Regions Research and Engineering Laboratory

An Engineering Approach to Management of Occupational and Community Noise Exposure at NASA Lewis Research Center

NASA Technical Reports Server (NTRS)

Cooper, Beth A.

1997-01-01

Workplace and environmental noise issues at NASA Lewis Research Center are effectively managed via a three-part program that addresses hearing conservation, community noise control, and noise control engineering. The Lewis Research Center Noise Exposure Management Program seeks to limit employee noise exposure and maintain community acceptance for critical research while actively pursuing engineered controls for noise generated by more than 100 separate research facilities and the associated services required for their operation.

Summary of Research Report Lewis Incubator for Technology

NASA Technical Reports Server (NTRS)

Zeman, Wayne P.

2000-01-01

This report summarizes the work done to establish and operate the Lewis Incubator for Technology (LIFT) for the period July 1996 through September 2000. The Lewis Incubator helps the startup and growth of technology-based businesses with the potential to incorporate technology from the NASA Glenn Research Center. During the grant period, LIFT began operation, met or exceeded all key performance measures, and continues its operation through a new cooperative agreement with NASA Glenn and also through continued funding from the State of Ohio.

Robot-assisted Ivor-Lewis esophagectomy with intrathoracic robot-sewn anastomosis.

PubMed

Jin, Runsen; Xiang, Jie; Han, Dingpei; Zhang, Yajie; Li, Hecheng

2017-11-01

This video clip demonstrated a performance of robot-assisted Ivor-Lewis esophagectomy with intrathoracic robot-sewn anastomosis. The patient had an esophageal mass located approximately 33 cm away from incisor, and robot-assisted Ivor-Lewis esophagectomy was applied for him. Importantly, a double-layer esophago-gastric anastomosis was made by robotic hand-sewn suture. Our early experience demonstrated that the robot-sewn intrathoracic anastomosis is feasible and safe with a lower complication rate and the absence of anastomotic leakage.

The Scope of Usage-Based Theory

PubMed Central

Ibbotson, Paul

2013-01-01

Usage-based approaches typically draw on a relatively small set of cognitive processes, such as categorization, analogy, and chunking to explain language structure and function. The goal of this paper is to first review the extent to which the “cognitive commitment” of usage-based theory has had success in explaining empirical findings across domains, including language acquisition, processing, and typology. We then look at the overall strengths and weaknesses of usage-based theory and highlight where there are significant debates. Finally, we draw special attention to a set of culturally generated structural patterns that seem to lie beyond the explanation of core usage-based cognitive processes. In this context we draw a distinction between cognition permitting language structure vs. cognition entailing language structure. As well as addressing the need for greater clarity on the mechanisms of generalizations and the fundamental units of grammar, we suggest that integrating culturally generated structures within existing cognitive models of use will generate tighter predictions about how language works. PMID:23658552

Lewy Body Dementia Research

MedlinePlus

... disorder that makes people physically act out their dreams, called REM sleep disorder or RBD, is a ... causes a person to physically act out their dreams and is a common in Lewy body dementia ( ...

Living and Coping with Ongoing Violence: A Cross-National Analysis of Children's Drawings Using Structured Rating Indices.

ERIC Educational Resources Information Center

Rudenberg, Stephanie Linda; Jansen, Patricia; Fridjohn, Peter

2001-01-01

Investigated the effectiveness of analyzing drawings of 8- to 12-year-old children as a method of understanding the effects of living and coping with ongoing civic unrest. Compared drawings by white and black South African children with those of children from Belfast, Ireland. Found cross-national differences in stress, emotion, adjustment, and…