Element speciation during nuclear glass alteration

NASA Astrophysics Data System (ADS)

Galoisy, L.; Calas, G.; Bergeron, B.; Jollivet, P.; Pelegrin, E.

2011-12-01

Assessing the long-term behavior of nuclear glasses implies the prediction of their long-term performance. An important controlling parameter is their evolution during interaction with water under conditions simulating geological repositories. After briefly recalling the major characteristics of the local and medium-range structure of borosilicate glasses of nuclear interest, we will present some structural features of this evolution. Specific structural tools used to determine the local structure of glass surfaces include synchrotron-radiation x-ray absorption spectroscopy with total electron yield detection. The evolution of the structure of glass surface has been determined at the Zr-, Fe-, Si- and Al-K edges and U-LIII edge. During alteration in near- or under-saturated conditions, some elements such as Fe change coordination, as other elements such as Zr only suffer structural modifications in under-saturated conditions. Uranium exhibits a modification of its speciation from an hexa-coordinated U(VI) in the borosilicate glass to an uranyl group in the gel. These structural modifications may explain the chemical dependence of the initial alteration rate and the transition to the residual regime. They also illustrate the molecular-scale origin of the processes at the origin of the glass-to-gel transformation. Eventually, they explain the provisional trapping of U by the alteration gel: the uranium retention factors in the gel depend on the alteration conditions, and thus on the nature of the resulting gel and on the trapping conditions.

Effect of high pressure homogenization on the structure and the interfacial and emulsifying properties of β-lactoglobulin.

PubMed

Ali, Ali; Le Potier, Isabelle; Huang, Nicolas; Rosilio, Véronique; Cheron, Monique; Faivre, Vincent; Turbica, Isabelle; Agnely, Florence; Mekhloufi, Ghozlene

2018-02-15

The effect of high pressure homogenization (HPH) on the structure of β-lactoglobulin (β-lg) was studied by combining spectroscopic, chromatographic, and electrophoretic methods. The consequences of the resulting structure modifications on oil/water (O/W) interfacial properties were also assessed. Moderated HPH treatment (100 MPa/4 cycles) showed no significant modification of protein structure and interfacial properties. However, a harsher HPH treatment (300 MPa/5 cycles) induced structural transformation, mainly from β-sheets to random coils, wide loss in lipocalin core, and protein aggregation via intermolecular disulfide bridges. HPH-modified β-lg displayed higher surface hydrophobicity leading to a faster adsorption rate at the interface and an earlier formation of an elastic interfacial film at C β-lg  = 0.1 wt%. However, no modification of the interfacial properties was observed at C β-lg  = 1 wt%. At this protein concentration, the prior denaturation of β-lg by HPH did not modify the droplet size of nanoemulsions prepared with these β-lg solutions as the aqueous phases. A slightly increased creaming rate was however observed. The effects of HPH and heat denaturations appeared qualitatively similar, but with differences in their extent. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid Assessment of Aircraft Structural Topologies for Multidisciplinary Optimization and Weight Estimation

NASA Technical Reports Server (NTRS)

Samareh, Jamshid A.; Sensmeier, mark D.; Stewart, Bret A.

2006-01-01

Algorithms for rapid generation of moderate-fidelity structural finite element models of air vehicle structures to allow more accurate weight estimation earlier in the vehicle design process have been developed. Application of these algorithms should help to rapidly assess many structural layouts before the start of the preliminary design phase and eliminate weight penalties imposed when actual structure weights exceed those estimated during conceptual design. By defining the structural topology in a fully parametric manner, the structure can be mapped to arbitrary vehicle configurations being considered during conceptual design optimization. Recent enhancements to this approach include the porting of the algorithms to a platform-independent software language Python, and modifications to specifically consider morphing aircraft-type configurations. Two sample cases which illustrate these recent developments are presented.

The Job Accommodation Scale (JAS): psychometric evaluation of a new measure of employer support for temporary job modifications.

PubMed

Shaw, William S; Kristman, Vicki L; Williams-Whitt, Kelly; Soklaridis, Sophie; Huang, Yueng-Hsiang; Côté, Pierre; Loisel, Patrick

2014-12-01

An employer offer of temporary job modification is a key strategy for facilitating return-to-work for musculoskeletal conditions, but there are no validated scales to assess the level of support for temporary job modifications across a range of job types and organizations. To pilot test a new 21-item self-report measure [the Job Accommodation Scale (JAS)] to assess its applicability, internal consistency, factor structure, and relation to physical job demands. Supervisors (N = 804, 72.8 % male, mean age = 46) were recruited from 19 employment settings in the USA and Canada and completed a 30-min online survey regarding job modification practices. As part of the survey, supervisors nominated and described a job position they supervised and completed the JAS for a hypothetical worker (in that position) with an episode of low back pain. Job characteristics were derived from the occupational informational network job classification database. The full response range (1-4) was utilized on all 21 items, with no ceiling or floor effects. Avoiding awkward postures was the most feasible accommodation and moving the employee to a different site or location was the least feasible. An exploratory factor analysis suggested five underlying factors (Modify physical workload; Modify work environment; Modify work schedule; Find alternate work; and Arrange for assistance), and there was an acceptable goodness-of-fit for the five parceled sub-factor scores as a single latent construct in a measurement model (structural equation model). Job accommodations were less feasible for more physical jobs and for heavier industries. The pilot administration of the JAS with respect to a hypothetical worker with low back pain showed initial support for its applicability, reliability, and validity when administered to supervisors. Future studies should assess its validity for use in actual disability cases, for a range of health conditions, and to assess different stakeholder opinions about the feasibility of job accommodation strategies.

The Job Accommodation Scale (JAS): Psychometric evaluation of a new measure of employer support for temporary job modifications

PubMed Central

Shaw, William S.; Kristman, Vicki L.; Williams-Whitt, Kelly; Soklaridis, Sophie; Huang, Yueng-Hsiang; Côté, Pierre; Loisel, Patrick

2015-01-01

INTRODUCTION An employer offer of temporary job modification is a key strategy for facilitating return-to-work (RTW) for musculoskeletal conditions, but there are no validated scales to assess the level of support for temporary job modifications across a range of job types and organizations. OBJECTIVE To pilot test a new 21-item self-report measure (the Job Accommodation Scale [JAS]) to assess its applicability, internal consistency, factor structure, and relation to physical job demands. METHODS Supervisors (N = 804, 72.8% male, mean age = 46) were recruited from 19 employment settings in the USA and Canada and completed a 30-min online survey regarding job modification practices. As part of the survey, supervisors nominated and described a job position they supervised and completed the JAS for a hypothetical worker (in that position) with an episode of low back pain. Job characteristics were derived from the occupational informational network job classification database. RESULTS The full response range (1–4) was utilized on all 21 items, with no ceiling or floor effects. Avoiding awkward postures was the most feasible accommodation and moving the employee to a different site or location was the least feasible. An exploratory factor analysis suggested five underlying factors (Modify physical workload; Modify work environment; Modify work schedule; Find alternate work; and Arrange for assistance), and there was an acceptable goodness-of-fit for the five parceled sub-factor scores as a single latent construct in a measurement model (structural equation model). Job accommodations were less feasible for more physical jobs and for heavier industries. CONCLUSIONS The pilot administration of the JAS with respect to a hypothetical worker with LBP showed initial support for its applicability, reliability, and validity when administered to supervisors. Future studies should assess its validity for use in actual disability cases, for a range of health conditions, and to assess different stakeholder opinions about the feasibility of job accommodation strategies. PMID:24643785

Efficient reanalysis of structures by a direct modification method. [local stiffness modifications of large structures

NASA Technical Reports Server (NTRS)

Raibstein, A. I.; Kalev, I.; Pipano, A.

1976-01-01

A procedure for the local stiffness modifications of large structures is described. It enables structural modifications without an a priori definition of the changes in the original structure and without loss of efficiency due to multiple loading conditions. The solution procedure, implemented in NASTRAN, involved the decomposed stiffness matrix and the displacement vectors of the original structure. It solves the modified structure exactly, irrespective of the magnitude of the stiffness changes. In order to investigate the efficiency of the present procedure and to test its applicability within a design environment, several real and large structures were solved. The results of the efficiency studies indicate that the break-even point of the procedure varies between 8% and 60% stiffness modifications, depending upon the structure's characteristics and the options employed.

Fluorine-18 radiolabeling of low-density lipoproteins: a potential approach for characterization and differentiation of metabolism of native and oxidized low-density lipoproteins in vivo.

PubMed

Pietzsch, Jens; Bergmann, Ralf; Rode, Katrin; Hultsch, Christina; Pawelke, Beate; Wuest, Frank; van den Hoff, Joerg

2004-11-01

Oxidative modification of low-density lipoprotein (LDL) is regarded as a crucial event in atherogenesis. Assessing the metabolic fate of oxidized LDL (oxLDL) in vivo with radiotracer techniques is hindered by the lack of suitable sensitive and specific radiolabeling methods. We evaluated an improved methodology based on the radiolabeling of native LDL (nLDL) and oxLDL with the positron emitter fluorine-18 ((18)F) by conjugation with N-succinimidyl-4-[(18)F]fluorobenzoate ([(18)F]SFB). We investigated whether radiolabeling of LDL induces adverse structural modifications. Results suggest that radiolabeling of both nLDL and oxLDL using [(18)F]SFB causes neither additional oxidative structural modifications of LDL lipids and proteins nor alteration of their biological activity and functionality, respectively. Thus, radiolabeling of LDL using [(18)F]SFB could prove to be a promising approach for studying the kinetics of oxLDL in vivo.

[Authorization, translation, back translation and language modification of the simplified Chinese adult comorbidity-27 index].

PubMed

Gao, L; Mao, C; Yu, G Y; Peng, X

2016-10-09

Objective: To translate the adult comorbidity evaluation-27(ACE-27) index authored by professor JF Piccirillo into Chinese and for the purpose of assessing the possible impact of comorbidity on survival of oral cancer patients and improving cancer staging. Methods: The translation included the following steps, obtaining permission from professor Piccirillo, translation, back translation, language modification, adjusted by the advice from the professors of oral and maxillofacial surgery. The test population included 154 patients who were admitted to Peking University of Stomatology during March 2011. Questionnaire survey was conducted on these patients. Retest of reliability, internal consistency reliability, content validity, and structure validity were performed. Results: The simplified Chinese ACE-27 index was established. The Cronbach's α was 0.821 in the internal consistency reliability test. The Kaiser-Meyer-Olkin (KMO) value of 8 items was 0.859 in the structure validity test. Conclusions: The simplified Chinese ACE-27 index has good feasibility and reliability. It is useful to assess the comorbidity of oral cancer patients.

Effect of deformation on the structural state of piracetam

NASA Astrophysics Data System (ADS)

Kanunnikova, O. M.; Mikhailova, S. S.; Karban', O. V.; Mukhgalin, V. V.; Aksenova, V. V.; Sen'kovskii, B. V.; Pechina, E. A.; Lad'yanov, V. I.

2016-04-01

The effect of various deformation actions on the structure-phase transformations in piracetam of modifications I and II with a sodium acetate addition is studied. Mechanical activation and pressing are shown to cause the polymorphic transformation of modification I into modification II, and modification III forms predominantly during severe plastic deformation by torsion. The structural difference between the piracetam molecules of modifications I and II is found to be retained in aqueous solutions.

Trial-Based Functional Analysis Informs Treatment for Vocal Scripting.

PubMed

Rispoli, Mandy; Brodhead, Matthew; Wolfe, Katie; Gregori, Emily

2018-05-01

Research on trial-based functional analysis has primarily focused on socially maintained challenging behaviors. However, procedural modifications may be necessary to clarify ambiguous assessment results. The purposes of this study were to evaluate the utility of iterative modifications to trial-based functional analysis on the identification of putative reinforcement and subsequent treatment for vocal scripting. For all participants, modifications to the trial-based functional analysis identified a primary function of automatic reinforcement. The structure of the trial-based format led to identification of social attention as an abolishing operation for vocal scripting. A noncontingent attention treatment was evaluated using withdrawal designs for each participant. This noncontingent attention treatment resulted in near zero levels of vocal scripting for all participants. Implications for research and practice are presented.

Response modification for enhanced operation and safety of bridges.

DOT National Transportation Integrated Search

2011-08-01

This report shows that safe extension of the service life of existing bridge structures is possible through bridge : health monitoring and structural response modification. To understand bridge health monitoring and structural : response modification...

The Chemistry and Pharmacology of Citrus Limonoids.

PubMed

Gualdani, Roberta; Cavalluzzi, Maria Maddalena; Lentini, Giovanni; Habtemariam, Solomon

2016-11-13

Citrus limonoids (CLs) are a group of highly oxygenated terpenoid secondary metabolites found mostly in the seeds, fruits and peel tissues of citrus fruits such as lemons, limes, oranges, pumellos, grapefruits, bergamots, and mandarins. Represented by limonin, the aglycones and glycosides of CLs have shown to display numerous pharmacological activities including anticancer, antimicrobial, antioxidant, antidiabetic and insecticidal among others. In this review, the chemistry and pharmacology of CLs are systematically scrutinised through the use of medicinal chemistry tools and structure-activity relationship approach. Synthetic derivatives and other structurally-related limonoids from other sources are include in the analysis. With the focus on literature in the past decade, the chemical classification of CLs, their physico-chemical properties as drugs, their biosynthesis and enzymatic modifications, possible ways of enhancing their biological activities through structural modifications, their ligand efficiency metrics and systematic graphical radar plot analysis to assess their developability as drugs are among those discussed in detail.

Preschool Education Programs for Children with Autism.

ERIC Educational Resources Information Center

Harris, Sandra L., Ed.; Handleman, Jan S., Ed.

This book highlights 10 preschool education programs for children with autism, focusing on each program's structure and content, diagnosis and assessment, staffing and administration, curriculum, integration, use of aversive behavior modification techniques, family involvement, and outcomes. The book consists of 11 chapters, the first of which is…

The structural damages of lens crystallins induced by peroxynitrite and methylglyoxal, two causative players in diabetic complications and preventive role of lens antioxidant components.

PubMed

Moghadam, Sogand Sasan; Oryan, Ahmad; Kurganov, Boris I; Tamaddon, Ali-Mohammad; Alavianehr, Mohammad Mehdi; Moosavi-Movahedi, Ali Akbar; Yousefi, Reza

2017-10-01

Peroxynitrite (PON) and methylglyoxal (MGO), two diabetes-associated compounds, are believed to be important causative players in development of diabetic cataracts. In the current study, different spectroscopic methods, gel electrophoresis, lens culture and microscopic assessments were applied to examine the impact of individual, subsequent or simultaneous modification of lens crystallins with MGO and PON on their structure, oligomerization and aggregation. The protein modifications were confirmed with detection of the significantly increased quantity of carbonyl groups and decreased levels of sulfhydryl, tyrosine and tryptophan. Also, lens proteins modification with these chemical agents was accompanied with important structural alteration, oligomerization, disulfide/chromophore mediated protein crosslinking and important proteolytic instability. All these structural damages were more pronounced when the lens proteins were modified in the presence of both mentioned chemical agents, either in sequential or simultaneous manner. Ascorbic acid and glutathione, as the main components of lens antioxidant defense mechanism, were also capable to markedly prevent the damaging effects of PON and MGO on lens crystallins, as indicated by gel electrophoresis. The results of this study may highlight the importance of lens antioxidant defense system in protection of crystallins against the structural insults induced by PON and MGO during chronic hyperglycemia in the diabetic patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Space shuttle orbiter leading-edge flight performance compared to design goals

NASA Technical Reports Server (NTRS)

Curry, D. M.; Johnson, D. W.; Kelly, R. E.

1983-01-01

Thermo-structural performance of the Space Shuttle orbiter Columbia's leading-edge structural subsystem for the first five (5) flights is compared with the design goals. Lessons learned from thse initial flights of the first reusable manned spacecraft are discussed in order to assess design maturity, deficiencies, and modifications required to rectify the design deficiencies. Flight data and post-flight inspections support the conclusion that the leading-edge structural subsystem hardware performance was outstanding for the initial five (5) flights.

Impact of active controls technology on structural integrity

NASA Technical Reports Server (NTRS)

Noll, Thomas; Austin, Edward; Donley, Shawn; Graham, George; Harris, Terry

1991-01-01

This paper summarizes the findings of The Technical Cooperation Program to assess the impact of active controls technology on the structural integrity of aeronautical vehicles and to evaluate the present state-of-the-art for predicting the loads caused by a flight-control system modification and the resulting change in the fatigue life of the flight vehicle. The potential for active controls to adversely affect structural integrity is described, and load predictions obtained using two state-of-the-art analytical methods are given.

Salmonella Typhimurium Enzymatically Landscapes the Host Intestinal Epithelial Cell (IEC) Surface Glycome to Increase Invasion*

PubMed Central

Park, Dayoung; Arabyan, Narine; Williams, Cynthia C.; Song, Ting; Mitra, Anupam; Weimer, Bart C.; Lebrilla, Carlito B.

2016-01-01

Although gut host-pathogen interactions are glycan-mediated processes, few details are known about the participating structures. Here we employ high-resolution mass spectrometric profiling to comprehensively identify and quantitatively measure the exact modifications of native intestinal epithelial cell surface N-glycans induced by S. typhimurium infection. Sixty minutes postinfection, select sialylated structures showed decreases in terms of total number and abundances. To assess the effect of cell surface mannosylation, we selectively rerouted glycan expression on the host using the alpha-mannosidase inhibitor, kifunensine, toward overexpression of high mannose. Under these conditions, internalization of S. typhimurium significantly increased, demonstrating that bacteria show preference for particular structures. Finally, we developed a novel assay to measure membrane glycoprotein turnover rates, which revealed that glycan modifications occur by bacterial enzyme activity rather than by host-derived restructuring strategies. This study is the first to provide precise structural information on how host N-glycans are altered to support S. typhimurium invasion. PMID:27754876

The Use of Gene Modification and Advanced Molecular Structure Analyses towards Improving Alfalfa Forage.

PubMed

Lei, Yaogeng; Hannoufa, Abdelali; Yu, Peiqiang

2017-01-29

Alfalfa is one of the most important legume forage crops in the world. In spite of its agronomic and nutritive advantages, alfalfa has some limitations in the usage of pasture forage and hay supplement. High rapid degradation of protein in alfalfa poses a risk of rumen bloat to ruminants which could cause huge economic losses for farmers. Coupled with the relatively high lignin content, which impedes the degradation of carbohydrate in rumen, alfalfa has unbalanced and asynchronous degradation ratio of nitrogen to carbohydrate (N/CHO) in rumen. Genetic engineering approaches have been used to manipulate the expression of genes involved in important metabolic pathways for the purpose of improving the nutritive value, forage yield, and the ability to resist abiotic stress. Such gene modification could bring molecular structural changes in alfalfa that are detectable by advanced structural analytical techniques. These structural analyses have been employed in assessing alfalfa forage characteristics, allowing for rapid, convenient and cost-effective analysis of alfalfa forage quality. In this article, we review two major obstacles facing alfalfa utilization, namely poor protein utilization and relatively high lignin content, and highlight genetic studies that were performed to overcome these drawbacks, as well as to introduce other improvements to alfalfa quality. We also review the use of advanced molecular structural analysis in the assessment of alfalfa forage for its potential usage in quality selection in alfalfa breeding.

The Use of Gene Modification and Advanced Molecular Structure Analyses towards Improving Alfalfa Forage

PubMed Central

Lei, Yaogeng; Hannoufa, Abdelali; Yu, Peiqiang

2017-01-01

Alfalfa is one of the most important legume forage crops in the world. In spite of its agronomic and nutritive advantages, alfalfa has some limitations in the usage of pasture forage and hay supplement. High rapid degradation of protein in alfalfa poses a risk of rumen bloat to ruminants which could cause huge economic losses for farmers. Coupled with the relatively high lignin content, which impedes the degradation of carbohydrate in rumen, alfalfa has unbalanced and asynchronous degradation ratio of nitrogen to carbohydrate (N/CHO) in rumen. Genetic engineering approaches have been used to manipulate the expression of genes involved in important metabolic pathways for the purpose of improving the nutritive value, forage yield, and the ability to resist abiotic stress. Such gene modification could bring molecular structural changes in alfalfa that are detectable by advanced structural analytical techniques. These structural analyses have been employed in assessing alfalfa forage characteristics, allowing for rapid, convenient and cost-effective analysis of alfalfa forage quality. In this article, we review two major obstacles facing alfalfa utilization, namely poor protein utilization and relatively high lignin content, and highlight genetic studies that were performed to overcome these drawbacks, as well as to introduce other improvements to alfalfa quality. We also review the use of advanced molecular structural analysis in the assessment of alfalfa forage for its potential usage in quality selection in alfalfa breeding. PMID:28146083

[THE HYGIENIC CONDITIONS OF THE INTERNAL ENVIRONMENT OF SYLVINITE CHAMBERS OF VARIOUS MODIFICATIONS].

PubMed

Barannikov, V G; Kirichenko, L V; Rusanova, E A; Dement'ev, S V; Vaĭsman, Ia I

2015-01-01

The performed comparative physiological-hygienic assessment of the conditions of the internal environment of salt sylvinite structures allowed to establish the complex of physical factors that have a favorable influence on the functional condition of the basic systems of the organism of patients.

An Assessment of the ECTS in Software Engineering: A Teaching Experience

ERIC Educational Resources Information Center

Salas-Morera, L.; Berral-Yeron, J.; Serrano-Gomez, I.; Martinez-Jimenez, P.

2009-01-01

Spain is currently implementing the regulatory modifications promulgated by the Declaration of Bologna, which should result in the updating of the structure of university degrees, and the inclusion of the European Credit Transfer and Accumulation System (ECTS) methodology. In some Spanish universities, the experimental adoption of this methodology…

The elusive structural role of ubiquitinated histones.

PubMed

Moore, Susan C; Jason, Laure; Ausió, Juan

2002-01-01

It is increasingly apparent that histone posttranslational modifications are important in chromatin structure and dynamics. However, histone ubiquitination has received little attention. Histones H1, H3, H2A, and H2B can be ubiquitinated in vivo, but the most prevalent are uH2A and uH2B. The size of this modification suggests some sort of structural impact. Physiological observations suggest that ubiquitinated histones may have multiple functions and structural effects. Ubiquitinated histones have been correlated with transcriptionally active DNA, implying that it may prevent chromatin folding or help maintain an open conformation. Also, in some organisms during spermiogenesis, a process involving extensive chromatin remodeling, uH2A levels increase just prior to histone replacement by protamines. Determination of chromatin's structural changes resulting from histone ubiquitination is therefore important. Recent work using reconstituted nucleosomes and chromatin fibers containing uH2A indicate that in the absence of linker histones, ubiquitination has little structural impact. DNase I digests and analytical ultracentrifugation of reconstituted ubiquitinated nucleosomes show no structural differences. Solubility assays using reconstituted chromatin fibers in the presence of divalent ions demonstrate that uH2A fibers are slightly more prone to aggregation than controls, and analytical ultracentrifugation results with different MgCl2 and NaCl concentrations determined that chromatin folding is not affected by this modification. Additional work to assess possible synergistic affects with histone acetylation also precludes any structural implications. Protamine displacement experiments concluded that the presence of uH2A does not significantly affect the ability of the protamines to displace histones. In addition, uH2A does not interfere with histone H1 binding to the nucleosome. While work with uH2B remains insufficient to come to any definitive conclusions about its structural impact, current work with uH-2A indicates that, contrary to predictions, this histone modification does not affect either nucleosome or chromatin structure. Consequently, the search for a structural role for ubiquitinated histones continues and their effect on and importance in chromatin dynamics remains elusive.

Exploiting tRNAs to Boost Virulence

PubMed Central

Albers, Suki; Czech, Andreas

2016-01-01

Transfer RNAs (tRNAs) are powerful small RNA entities that are used to translate nucleotide language of genes into the amino acid language of proteins. Their near-uniform length and tertiary structure as well as their high nucleotide similarity and post-transcriptional modifications have made it difficult to characterize individual species quantitatively. However, due to the central role of the tRNA pool in protein biosynthesis as well as newly emerging roles played by tRNAs, their quantitative assessment yields important information, particularly relevant for virus research. Viruses which depend on the host protein expression machinery have evolved various strategies to optimize tRNA usage—either by adapting to the host codon usage or encoding their own tRNAs. Additionally, several viruses bear tRNA-like elements (TLE) in the 5′- and 3′-UTR of their mRNAs. There are different hypotheses concerning the manner in which such structures boost viral protein expression. Furthermore, retroviruses use special tRNAs for packaging and initiating reverse transcription of their genetic material. Since there is a strong specificity of different viruses towards certain tRNAs, different strategies for recruitment are employed. Interestingly, modifications on tRNAs strongly impact their functionality in viruses. Here, we review those intersection points between virus and tRNA research and describe methods for assessing the tRNA pool in terms of concentration, aminoacylation and modification. PMID:26797637

Redox proteomic evaluation of oxidative modification and recovery in a 3D reconstituted human skin tissue model exposed to UVB.

PubMed

Dyer, J M; Haines, S R; Thomas, A; Wang, W; Walls, R J; Clerens, S; Harland, D P

2017-04-01

Exposure to UV in humans resulting in sunburn triggers a complex series of events that are a mix of immediate and delayed damage mediation and healing. While studies on the effects of UV exposure on DNA damage and repair have been reported, changes in the oxidative modification of skin proteins are poorly understood at the molecular level, despite the important role played by structural proteins in skin tissue, and the effect of the integrity of these proteins on skin appearance and health. Proteomic molecular mapping of oxidation was here applied to try to enhance understanding of skin damage and recovery from oxidative damage and UVB exposure. A redox proteomic-based approach was applied to evaluating skin protein modification when exposed to varying doses of UVB after initial oxidative stress, via tracking changes in protein oxidation during the healing process in vitro using a full-thickness reconstituted human skin tissue model. Bioassays and structural evaluation confirmed that our cultured skin tissues underwent a normal physiological response to UVB exposure. A set of potential skin marker peptides was generated, for use in tracking skin protein oxidative modification. Exposure to UVB after thermal oxidative stress was found to result in higher levels of skin protein oxidation than a non-irradiated control for up to seven days after exposure. Recovery of the skin proteins from oxidative stress, as assessed by the overall protein oxidation levels, was found to be impaired by UVB exposure. Oxidative modification was largely observed in skin structural proteins. Exposure of skin proteins to UVB exacerbates oxidative damage to structural skin proteins, with higher exposure levels leading to increasingly impaired recovery from this damage. This has potential implications for the functional performance of the proteins and inter-related skin health and cosmetic appearance. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Modification of nanofibrillated cellulose using amphiphilic block-structured galactoglucomannans.

PubMed

Lozhechnikova, Alina; Dax, Daniel; Vartiainen, Jari; Willför, Stefan; Xu, Chunlin; Österberg, Monika

2014-09-22

Nanofibrillated cellulose (NFC) and hemicelluloses have shown to be highly promising renewable components both as barrier materials and in novel biocomposites. However, the hydrophilic nature of these materials restricts their use in some applications. In this work, the usability of modified O-acetyl galactoglucomannan (GGM) for modification of NFC surface properties was studied. Four GGM-block-structured, amphiphilic derivatives were synthesized using either fatty acids or polydimethylsiloxane as hydrophobic tails. The adsorption of these GGM derivatives was consecutively examined in aqueous solution using a quartz crystal microbalance with dissipation monitoring (QCM-D). It was found that the hydrophobic tails did not hinder adsorption of the GGM derivatives to cellulose, which was concluded to be due to the presence of the native GGM-block with high affinity to cellulose. The layer properties of the adsorbed block-co-polymers were discussed and evaluated. Self-standing NFC films were further prepared and coated with the GGM derivatives and the effect of the surface modification on wetting properties and oxygen permeability (OP) of the modified films was assessed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Toxicological features of maleilated polyflavonoids from Pinus radiata (D. Don.) as potential functional additives for biomaterials design.

PubMed

García, Danny E; Medina, Paulina A; Zúñiga, Valentina I

2017-11-01

Polyflavonoids from Pinus radiata (D. Don.) are an abundant natural oligomers highly desirable as renewable chemicals. However, structural modification of polyflavonoids is a viable strategy in order to use such polyphenols as macrobuilding-blocks for biomaterial design. Polyflavonoids were esterified with three five-member cyclic anhydrides (maleic, itaconic, and citraconic) at 20 °C during 24 h in order to diversify physicochemical-, and biological-properties for agricultural, and food-packaging applications. In addition, the influence of the chemical modification, as well as the chemical structure of the grafting on toxicological features was evaluated. Structural features of derivatives were analyzed by spectroscopy (FT-IR and 1 H-NMR), and the degree of substitution was calculated. Toxicological profile was assessed by using three target species in a wide range of concentration (0.01-100 mgL - 1 ). Effect of polyflavonoids on the growth rate (Selenastrum capricornutum), mortality (Daphnia magna), and germination and radicle length (Lactuca sativa) was determined. Chemical modification affects the toxicological profile on the derivatives in a high extent. Results described remarkable differences in function of the target specie. The bioassays indicate differences of the polyflavonoids toxicological profile associated to the chemical structure of the grafting. Results allowed conclude that polyflavonoids from pine bark show slight toxic properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Insulin sensitizing drugs for weight loss in women of reproductive age who are overweight or obese: systematic review and meta-analysis.

PubMed

Nieuwenhuis-Ruifrok, A E; Kuchenbecker, W K H; Hoek, A; Middleton, P; Norman, R J

2009-01-01

Women of reproductive age, who are overweight or obese, are prone to infertility. Weight loss in these women leads to increased fecundity, higher chances of conception after infertility treatment and improved pregnancy outcome. In spite of the advantages, most patients have difficulty in losing weight and often regain lost weight over time. This review assesses whether treatment with insulin sensitizing drugs contributes to weight loss, compared with diet or a lifestyle modification programme. After a systematic search of the literature, only randomized controlled trials (RCTs), investigating the effect of insulin sensitizing drugs on weight loss compared with placebo and diet and/or a lifestyle modification programme, were included. Subjects were restricted to women of reproductive age. The main outcome measure was change in body mass index (BMI). Only 14 trials, unintentionally all but two on women with polycystic ovary syndrome (PCOS) only, were included in the analysis. Treatment with metformin showed a statistically significant decrease in BMI compared with placebo (weighted mean difference, -0.68; 95% CI -1.13 to -0.24). There was some indication of greater effect with high-dose metformin (>1500 mg/day) and longer duration of therapy (>8 weeks). Limitations were power, low use of intention-to-treat analysis and heterogeneity of the studies. A structured lifestyle modification programme to achieve weight loss should still be the first line treatment in obese women with or without PCOS. Adequately powered RCTs are required to confirm the findings of this review and to assess whether the addition of high-dose metformin therapy to a structured lifestyle modification programme might contribute to more weight loss.

Facilitating peer based learning through summative assessment - An adaptation of the Objective Structured Clinical Assessment tool for the blended learning environment.

PubMed

Wikander, Lolita; Bouchoucha, Stéphane L

2018-01-01

Adapting a course from face to face to blended delivery necessitates that assessments are modified accordingly. In Australia the Objective Structured Clinical Assessment tool, as a derivative from the Objective Structured Clinical Examination, has been used in the face-to-face delivery mode as a formative or summative assessment tool in medicine and nursing since 1990. The Objective Structured Clinical Assessment has been used at Charles Darwin University to assess nursing students' simulated clinical skills prior to the commencement of their clinical placements since 2008. Although the majority of the course is delivered online, students attend a one-week intensive clinical simulation block yearly, prior to attending clinical placements. Initially, the Objective Structured Clinical Assessment was introduced as a lecturer assessed summative assessment, over time it was adapted to better suit the blended learning environment. The modification of the tool from an academic to peer assessed assessment tool, was based on the empirical literature, student feedback and a cross-sectional, qualitative study exploring academics' perceptions of the Objective Structured Clinical Assessment (Bouchoucha et al., 2013a, b). This paper presents an overview of the process leading to the successful adaptation of the Objective Structured Clinical Assessment to suit the requirements of a preregistration nursing course delivered through blended learning. This is significant as many universities are moving their curriculum to fully online or blended delivery, yet little attention has been paid to adapting the assessment of simulated clinical skills. The aim is to identify the benefits and drawbacks of using the peer assessed Objective Structured Clinical Assessment and share recommendations for successful implementation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural dynamic analysis of the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Scott, L. P.; Jamison, G. T.; Mccutcheon, W. A.; Price, J. M.

1981-01-01

This structural dynamic analysis supports development of the SSME by evaluating components subjected to critical dynamic loads, identifying significant parameters, and evaluating solution methods. Engine operating parameters at both rated and full power levels are considered. Detailed structural dynamic analyses of operationally critical and life limited components support the assessment of engine design modifications and environmental changes. Engine system test results are utilized to verify analytic model simulations. The SSME main chamber injector assembly is an assembly of 600 injector elements which are called LOX posts. The overall LOX post analysis procedure is shown.

Assessing Analytical Similarity of Proposed Amgen Biosimilar ABP 501 to Adalimumab.

PubMed

Liu, Jennifer; Eris, Tamer; Li, Cynthia; Cao, Shawn; Kuhns, Scott

2016-08-01

ABP 501 is being developed as a biosimilar to adalimumab. Comprehensive comparative analytical characterization studies have been conducted and completed. The objective of this study was to assess analytical similarity between ABP 501 and two adalimumab reference products (RPs), licensed by the United States Food and Drug Administration (adalimumab [US]) and authorized by the European Union (adalimumab [EU]), using state-of-the-art analytical methods. Comprehensive analytical characterization incorporating orthogonal analytical techniques was used to compare products. Physicochemical property comparisons comprised the primary structure related to amino acid sequence and post-translational modifications including glycans; higher-order structure; primary biological properties mediated by target and receptor binding; product-related substances and impurities; host-cell impurities; general properties of the finished drug product, including strength and formulation; subvisible and submicron particles and aggregates; and forced thermal degradation. ABP 501 had the same amino acid sequence and similar post-translational modification profiles compared with adalimumab RPs. Primary structure, higher-order structure, and biological activities were similar for the three products. Product-related size and charge variants and aggregate and particle levels were also similar. ABP 501 had very low residual host-cell protein and DNA. The finished ABP 501 drug product has the same strength with regard to protein concentration and fill volume as adalimumab RPs. ABP 501 and the RPs had a similar stability profile both in normal storage and thermal stress conditions. Based on the comprehensive analytical similarity assessment, ABP 501 was found to be similar to adalimumab with respect to physicochemical and biological properties.

The Use of Gene Modification and Advanced Molecular Structure Analyses towards Improving Alfalfa Forage

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

Lei, Yaogeng; Hannoufa, Abdelali; Yu, Peiqiang

Alfalfa is one of the most important legume forage crops in the world. In spite of its agronomic and nutritive advantages, alfalfa has some limitations in the usage of pasture forage and hay supplement. High rapid degradation of protein in alfalfa poses a risk of rumen bloat to ruminants which could cause huge economic losses for farmers. Coupled with the relatively high lignin content, which impedes the degradation of carbohydrate in rumen, alfalfa has unbalanced and asynchronous degradation ratio of nitrogen to carbohydrate (N/CHO) in rumen. Genetic engineering approaches have been used to manipulate the expression of genes involved inmore » important metabolic pathways for the purpose of improving the nutritive value, forage yield, and the ability to resist abiotic stress. Such gene modification could bring molecular structural changes in alfalfa that are detectable by advanced structural analytical techniques. These structural analyses have been employed in assessing alfalfa forage characteristics, allowing for rapid, convenient and cost-effective analysis of alfalfa forage quality. In this article, we review two major obstacles facing alfalfa utilization, namely poor protein utilization and relatively high lignin content, and highlight genetic studies that were performed to overcome these drawbacks, as well as to introduce other improvements to alfalfa quality. We also review the use of advanced molecular structural analysis in the assessment of alfalfa forage for its potential usage in quality selection in alfalfa breeding.« less

Structural modifications of graphyne layers consisting of carbon atoms in the sp- and sp{sup 2}-hybridized states

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

Belenkov, E. A., E-mail: belenkov@csu.ru; Mavrinskii, V. V.; Belenkova, T. E.

2015-05-15

A model scheme is proposed for obtaining layered compounds consisting of carbon atoms in the sp- and (vnsp){sup 2}-hybridized states. This model is used to find the possibility of existing the following seven basic structural modifications of graphyne: α-, β1-, β2-, β3-, γ1-, γ2-, and γ3-graphyne. Polymorphic modifications β3 graphyne and γ3 graphyne are described. The basic structural modifications of graphyne contain diatomic polyyne chains and consist only of carbon atoms in two different crystallographically equivalent states. Other nonbasic structural modifications of graphyne can be formed via the elongation of the carbyne chains that connect three-coordinated carbon atoms and viamore » the formation of graphyne layers with a mixed structure consisting of basic layer fragments, such as α-β-graphyne, α-γ-graphyne, and β-γ-graphyne. The semiempirical quantum-mechanical MNDO, AM1, and PM3 methods and ab initio STO6-31G basis calculations are used to find geometrically optimized structures of the basic graphyne layers, their structural parameters, and energies of their sublimation. The energy of sublimation is found to be maximal for γ2-graphyne, which should be the most stable structural modification of graphyne.« less

Knowledge, attitude and practice regarding lifestyle modification in type 2 diabetic patients.

PubMed

Okonta, Henry I; Ikombele, John B; Ogunbanjo, Gboyega A

2014-12-09

The number of persons suffering from type 2 diabetes mellitus continues to rise worldwide and causes significant morbidity and mortality, especially in the developing world. Behaviour change and adoption of healthy lifestyle habits help to prevent or slow down the complications of type 2 diabetes mellitus. However, the knowledge and practice of healthy lifestyles in many diabetic patients have been inadequate. This study sought to establish the knowledge, attitude and practice regarding lifestyle modification amongst type 2 diabetic patients. The diabetic clinic of Mamelodi hospital, Pretoria, Gauteng Province, South Africa. A cross-sectional study was done using a structured questionnaire amongst 217 type 2 diabetic patients seen at the diabetic clinic of Mamelodi hospital. Baseline characteristics of the participants were obtained and their knowledge, attitude and practice regarding lifestyle modification were assessed. Of the 217 participants, 154 (71%) were obese and 15 (7%) were morbidly obese. The majority of respondents (92.2%) had poor knowledge of the benefits of exercise, weight loss and a healthy diet. What is interesting is that the majority (97.7%) demonstrated bad practices in relation to lifestyle modifications, although over four-fifths (84.3%) had a positive attitude toward healthy lifestyle modifications. Despite the positive attitudes of respondents toward healthy lifestyle modifications, the knowledge and practice regarding lifestyle modifications amongst type 2 diabetes mellitus participants seen at Mamelodi hospital were generally poor.

Protein-protein binding before and after photo-modification of albumin

NASA Astrophysics Data System (ADS)

Rozinek, Sarah C.; Glickman, Randolph D.; Thomas, Robert J.; Brancaleon, Lorenzo

2016-03-01

Bioeffects of directed-optical-energy encompass a wide range of applications. One aspect of photochemical interactions involves irradiating a photosensitizer with visible light in order to induce protein unfolding and consequent changes in function. In the past, irradiation of several dye-protein combinations has revealed effects on protein structure. Beta lactoglobulin, human serum albumin (HSA) and tubulin have all been photo-modified with meso-tetrakis(4- sulfonatophenyl)porphyrin (TSPP) bound, but only in the case of tubulin has binding caused a verified loss of biological function (loss of ability to form microtubules) as a result of this light-induced structural change. The current work questions if the photo-induced structural changes that occur to HSA, are sufficient to disable its biological function of binding to osteonectin. The albumin-binding protein, osteonectin, is about half the molecular weight of HSA, so the two proteins and their bound product can be separated and quantified by size exclusion high performance liquid chromatography. TSPP was first bound to HSA and irradiated, photo-modifying the structure of HSA. Then native HSA or photo-modified HSA (both with TSPP bound) were compared, to assess loss in HSA's innate binding ability as a result of light-induced structure modification.

Reduction and alkylation of peanut allergen isoforms Ara h 2 and Ara h 6; characterization of intermediate- and end products.

PubMed

Apostolovic, Danijela; Luykx, Dion; Warmenhoven, Hans; Verbart, Dennis; Stanic-Vucinic, Dragana; de Jong, Govardus A H; Velickovic, Tanja Cirkovic; Koppelman, Stef J

2013-12-01

Conglutins, the major peanut allergens, Ara h 2 and Ara h 6, are highly structured proteins stabilized by multiple disulfide bridges and are stable towards heat-denaturation and digestion. We sought a way to reduce their potent allergenicity in view of the development of immunotherapy for peanut allergy. Isoforms of conglutin were purified, reduced with dithiothreitol and subsequently alkylated with iodoacetamide. The effect of this modification was assessed on protein folding and IgE-binding. We found that all disulfide bridges were reduced and alkylated. As a result, the secondary structure lost α-helix and gained some β-structure content, and the tertiary structure stability was reduced. On a functional level, the modification led to a strongly decreased IgE-binding. Using conditions for limited reduction and alkylation, partially reduced and alkylated proteins were found with rearranged disulfide bridges and, in some cases, intermolecular cross-links were found. Peptide mass finger printing was applied to control progress of the modification reaction and to map novel disulfide bonds. There was no preference for the order in which disulfides were reduced, and disulfide rearrangement occurred in a non-specific way. Only minor differences in kinetics of reduction and alkylation were found between the different conglutin isoforms. We conclude that the peanut conglutins Ara h 2 and Ara h 6 can be chemically modified by reduction and alkylation, such that they substantially unfold and that their allergenic potency decreases. © 2013.

Direct runoff assessment using modified SME method in catchments in the Upper Vistula River Basin

NASA Astrophysics Data System (ADS)

Wałęga, A.; Rutkowska, A.; Grzebinoga, M.

2017-04-01

Correct determination of direct runoff is crucial for proper and safe dimensioning of hydroengineering structures. It is commonly assessed using SCS-CN method developed in the United States. However, due to deficiencies of this method, many improvements and modifications have been proposed. In this paper, a modified Sahu-Mishra-Eldo (SME) method was introduced and tested for three catchments located in the upper Vistula basin. Modification of SME method involved a determination of maximum potential retention S based on CN parameter derived from SCS-CN method. The modified SME method yielded direct runoff values very similar to those observed in the investigated catchments. Moreover, it generated significantly smaller errors in the direct runoff estimation as compared with SCS-CN and SME methods in the analyzed catchments. This approach may be used for estimating the runoff in uncontrolled catchments.

Cyclosporin A inhibits UV-radiation-induced membrane damage but is unable to inhibit carboxyatractyloside-induced permeability transition.

PubMed

García, Noemí; Zazueta, Cecilia; El-Hafidi, Mohammed; Pavón, Natalia; Martínez-Abundis, Eduardo; Hernández-Esquivel, Luz; Chávez, Edmundo

2009-11-01

This work was undertaken to gain further information on the chemical characteristics of the membrane entity involved in the formation of the nonspecific pore. Mitochondria were subjected to oxidative stress by exposure to UV radiation. The results indicate that ultraviolet C radiation induces structural modifications in the adenine nucleotide translocase that lead to membrane permeability transition. Membrane leakage was assessed by measuring mitochondrial Ca2+ transport, the transmembrane electric gradient, and mitochondrial swelling. UV-irradiated mitochondria were unable to retain matrix Ca2+ or to maintain a high level of membrane potential when Ca2+ was added; furthermore, UV-irradiated mitochondria underwent large amplitude swelling. Release of cytochrome c and formation of malondialdehyde, owing to lipid peroxidation, were also seen. Structural modifications of the translocase were revealed by an increase in the binding of the fluorescent probe eosin-5-maleimide to thiol residues of the ADP/ATP carrier. These modifications, taken together with findings indicating that cyclosporin resulted unable to inhibit carboxyatractyloside-induced permeability transition, prompted us to conclude that the translocase could constitute the nonspecific pore or at least be an important modulator of it.

Crystal structure of laser-induced subsurface modifications in Si

NASA Astrophysics Data System (ADS)

Verburg, P. C.; Smillie, L. A.; Römer, G. R. B. E.; Haberl, B.; Bradby, J. E.; Williams, J. S.; Huis in't Veld, A. J.

2015-08-01

Laser-induced subsurface modification of dielectric materials is a well-known technology. Applications include the production of optical components and selective etching. In addition to dielectric materials, the subsurface modification technology can be applied to silicon, by employing near to mid-infrared radiation. An application of subsurface modifications in silicon is laser-induced subsurface separation, which is a method to separate wafers into individual dies. Other applications for which proofs of concept exist are the formation of waveguides and resistivity tuning. However, limited knowledge is available about the crystal structure of subsurface modifications in silicon. In this work, we investigate the geometry and crystal structure of laser-induced subsurface modifications in monocrystalline silicon wafers. In addition to the generation of lattice defects, we found that transformations to amorphous silicon and Si -iii/Si -xii occur as a result of the laser irradiation.

Vision & Strategy: Predictive Ecotoxicology in the 21st Century

DTIC Science & Technology

2011-01-01

their relative abundance or modifications QSARs —Correlation of ecological or toxicological activity with chemical structure to understand or predict...data and collection methods. The dramatic increase in the amount of toxicological data we can collect and analyze is complemented by our improved...diverse disciplines such as biochemistry, ecology, molecular biology, toxicology , bioinformatics, and health and environmental risk assess- ment

The XFV-12A Thrust-Augmented Wing (TAW) prototype aircraft

NASA Technical Reports Server (NTRS)

Murphy, R.; Lewis, E. L.

1979-01-01

The XFV-12A, a unique V/STOL technology prototype aircraft being developed for the Navy, is described. The innovative design features a thrust augmented wing and a canard ejector. Structural, functional, and control test performances are discussed. Static tether test results are also discussed. Assessment of test results are given along with projections for future modification areas.

BWR Steam Dryer Alternating Stress Assessment Procedures

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

Morante, R. J.; Hambric, S. A.; Ziada, S.

2016-12-01

This report presents an overview of Boiling Water Reactor (BWR) steam dryer design; the fatigue cracking failures that occurred at the Quad Cities (QC) plants and their root causes; a history of BWR Extended Power Uprates (EPUs) in the USA; and a discussion of steam dryer modifications/replacements, alternating stress mechanisms on steam dryers, and structural integrity evaluations (static and alternating stress).

Assessment of the structure of pegylated-recombinant protein therapeutics by the NMR fingerprint assay.

PubMed

Hodgson, Derek J; Aubin, Yves

2017-05-10

A number of recombinant protein therapeutic products, such as filgrastim (methionyl granulocyte colony stimulating factor [Met-GCSF] used to boost the immune system in chemotherapy treated cancer patients), and interferon alpha-2 (used for the treatment of various viral infections), have been chemically modified with the addition of a polyethylene glycol (PEG) chain. This modification prolongs residency of the drug in the body and reduces metabolic degradation, which allows less frequent administration of the products. Here we show how NMR spectroscopy methods can assess the higher order structure (HOS) of pegylated-filgrastim (Neulasta®), pegylated interferon-α2a (Pegasys®) pegylated interferon-α2b (PEG-Intron®) purchased from the marketplace. The addition of the PEG moiety effectively doubles the molecular weight of the three products. This presents a significant challenge for the application of NMR techniques. Nevertheless, the results showed that high-resolution spectra could be recorded for two of the three products. Comparison of the spectra of the pegylated protein and the non-pegylated protein shows that the chemical modification did not alter the HOS of these proteins. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Synthetic Modifications In the Frequency Domain for Finite Element Model Update and Damage Detection

DTIC Science & Technology

2017-09-01

Sensitivity-based finite element model updating and structural damage detection has been limited by the number of modes available in a vibration test and...increase the number of modes and corresponding sensitivity data by artificially constraining the structure under test, producing a large number of... structural modifications to the measured data, including both springs-to-ground and mass modifications. This is accomplished with frequency domain

Dorsal Failures: From Saddle Deformity to Pollybeak.

PubMed

Hamilton, Grant S

2018-06-01

The nasal dorsum is an important component of a rhinoplasty and may be the primary motivation for seeking surgery. The nasal dorsum is a complex three-dimensional shape that is shrouded by local anesthetic and edema during surgery. This makes an accurate assessment of the surgical changes challenging. Complications related to dorsal modification include imbalances from over- or underresection of the structures of the nasal dorsum, inadequate or overaugmentation, an open-roof deformity, pollybeak, saddle nose, inverted-V, warped cartilage, visible grafts, contour problems, graft malposition, and extrusion. This review will discuss the common problems that can occur with dorsal modification during rhinoplasty. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Crystal structure of laser-induced subsurface modifications in Si

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

Verburg, P. C.; Smillie, L. A.; Römer, G. R. B. E.

2015-06-04

Laser-induced subsurface modification of dielectric materials is a well-known technology. Applications include the production of optical components and selective etching. In addition to dielectric materials, the subsurface modification technology can be applied to silicon, by employing near to mid-infrared radiation. An application of subsurface modifications in silicon is laser-induced subsurface separation, which is a method to separate wafers into individual dies. Other applications for which proofs of concept exist are the formation of waveguides and resistivity tuning. However, limited knowledge is available about the crystal structure of subsurface modifications in silicon. In this paper, we investigate the geometry and crystalmore » structure of laser-induced subsurface modifications in monocrystalline silicon wafers. Finally, in addition to the generation of lattice defects, we found that transformations to amorphous silicon and Si-iii/Si-xii occur as a result of the laser irradiation.« less

General Characteristics of the Changes in the Thermal Stability of Proteins and Enzymes After the Chemical Modification of Their Functional Groups

NASA Astrophysics Data System (ADS)

Kutuzova, G. D.; Ugarova, N. N.; Berezin, Ilya V.

1984-11-01

The principal structural and physicochemical factors determining the stability of protein macromolecules in solution and the characteristics of the structure of the proteins from thermophilic microorganisms are examined. The mechanism of the changes in the thermal stability of proteins and enzymes after the chemical modification of their functional side groups and the experimental data concerning the influence of chemical modification on the thermal stability of proteins are analysed. The dependence of the stabilisation effect and of the changes in the structure of protein macromolecules on the degree of modification and on the nature of the modified groups and the groups introduced into proteins in the course of modification (their charge and hydrophobic properties) is demonstrated. The great practical value of the method of chemical modification for the preparation of stabilised forms of biocatalysts is shown in relation to specific examples. The bibliography includes 178 references.

Argonne Physics Division - E-906/SeaQuest

Science.gov Websites

measure the quark and antiquark structure of the nucleon and the modifications to that structure which experiment will also examine the modifications to the antiquark structure of the proton from nuclear binding

Assessing medical decision making capacity among cancer patients: Preliminary clinical experience of using a competency assessment instrument.

PubMed

Akechi, Tatsuo; Okuyama, Toru; Uchida, Megumi; Sugano, Koji; Kubota, Yosuke; Ito, Yoshinori; Sakamoto, Nobuhiro; Kizawa, Yoshiyuki

2015-12-01

This study investigates the usefulness of the Structured Interview for Competency and Incompetency Assessment Testing and Ranking Inventory (SICIATRI) for cancer patients, which is a structured interview that assesses a patient's competency in clinical practice. The SICIATRI, originally developed to measure patients' competency to give informed consent, were administered referred cancer patients who needed for assessing medical decision making capacity. The usefulness of the SICIATRI was investigated retrospectively. Recommendation for modification of the SICIATRI for cancer patients if applicable were made by the research team. Among the 433 cancer patients referred for psychiatric consultation, 12 were administered the SICIATRI and all of the administration were conducted without big problems. All patients were 60 years or older. The most common purpose for competency evaluation was to analyze patients' understanding of the anti-cancer treatment proposed by oncologists, followed by their refusal of the treatment. Half of the patients (n = 6) were diagnosed with delirium and three among them were judged as having the most impaired status of a patient's competency. Two patients (17%) were diagnosed with major depression and another two (17%) were mental retardation and each one patient was diagnosed with dementia and past history of alcohol dependence. Among 6 patients without delirium 5 subjects including a dementia patient were judged as fully competent. Total of 5 small potential modifications of the SICIATRI for its use with Japanese cancer patients were recommended. Our experience suggests that the SICIATRI is a useful instrument for psycho-oncology clinical practice.

Nε-Acryloyllysine Piperazides as Irreversible Inhibitors of Transglutaminase 2: Synthesis, Structure-Activity Relationships, and Pharmacokinetic Profiling.

PubMed

Wodtke, Robert; Hauser, Christoph; Ruiz-Gómez, Gloria; Jäckel, Elisabeth; Bauer, David; Lohse, Martin; Wong, Alan; Pufe, Johanna; Ludwig, Friedrich-Alexander; Fischer, Steffen; Hauser, Sandra; Greif, Dieter; Pisabarro, M Teresa; Pietzsch, Jens; Pietsch, Markus; Löser, Reik

2018-05-24

Transglutaminase 2 (TGase 2)-catalyzed transamidation represents an important post-translational mechanism for protein modification with implications in physiological and pathophysiological conditions, including fibrotic and neoplastic processes. Consequently, this enzyme is considered a promising target for the diagnosis of and therapy for these diseases. In this study, we report on the synthesis and kinetic characterization of N ε -acryloyllysine piperazides as irreversible inhibitors of TGase 2. Systematic structural modifications on 54 new compounds were performed with a major focus on fluorine-bearing substituents due to the potential of such compounds to serve as radiotracer candidates for positron emission tomography. The determined inhibitory activities ranged from 100 to 10 000 M -1 s -1 , which resulted in comprehensive structure-activity relationships. Structure-activity correlations using various substituent parameters accompanied by covalent docking studies provide an advanced understanding of the molecular recognition for this inhibitor class within the active site of TGase 2. Selectivity profiling of selected compounds for other transglutaminases demonstrated an excellent selectivity toward transglutaminase 2. Furthermore, an initial pharmacokinetic profiling of selected inhibitors was performed, including the assessment of potential membrane permeability and liver microsomal stability.

Navier-Stokes simulations of slender axisymmetric shapes in supersonic, turbulent flow

NASA Astrophysics Data System (ADS)

Moran, Kenneth J.; Beran, Philip S.

1994-07-01

Computational fluid dynamics is used to study flows about slender, axisymmetric bodies at very high speeds. Numerical experiments are conducted to simulate a broad range of flight conditions. Mach number is varied from 1.5 to 8 and Reynolds number is varied from 1 X 10(exp 6)/m to 10(exp 8)/m. The primary objective is to develop and validate a computational and methodology for the accurate simulation of a wide variety of flow structures. Accurate results are obtained for detached bow shocks, recompression shocks, corner-point expansions, base-flow recirculations, and turbulent boundary layers. Accuracy is assessed through comparison with theory and experimental data; computed surface pressure, shock structure, base-flow structure, and velocity profiles are within measurement accuracy throughout the range of conditions tested. The methodology is both practical and general: general in its applicability, and practicaal in its performance. To achieve high accuracy, modifications to previously reported techniques are implemented in the scheme. These modifications improve computed results in the vicinity of symmetry lines and in the base flow region, including the turbulent wake.

TiO2 induced structural modifications in Cs containing borosilicate glasses: Raman and infrared studies

NASA Astrophysics Data System (ADS)

Pandey, M.; Banerjee, D.; Sudarsan, V.; Kshirsagar, R. J.

2018-04-01

Effect of TiO2 addition in Cs containing Sodium-borosilicate glasses is studied using Raman and infrared spectroscopic techniques. As revealed from infrared and Raman studies, TiO2 does not form segregated phase, but instead enters into the borosilicate network. It is further observed that TiO2 addition results in modifications of the borate and silicate structural units by transforming into tetraborates and metasilicate structural units. These structural modifications are responsible for Cs immobilization, leach rate and chemical durability of these glasses.

Evaluation of substituted phenalenone analogues as antiplasmodial agents.

PubMed

Gutiérrez, David; Flores, Ninoska; Abad-Grillo, Teresa; McNaughton-Smith, Grant

2013-10-01

A set of derivatives encompassing structural modifications on the privileged phenalenone scaffold were assessed for their antiplasmodial activities against a strain of chloroquine sensitive Plasmodium falciparum F32. Two compounds exhibited considerable effects against the malaria parasite (IC₅₀ ≤ 1 μg/mL), one of which maintained the same level of activity in a chloroquine-resistant strain. This is the first record of antiplasmodial activity on this type of scaffold, providing a new structural motif as a new lead for antimalarial activity. Copyright © 2013 Elsevier Inc. All rights reserved.

14 CFR 121.1109 - Supplemental inspections.

Code of Federal Regulations, 2010 CFR

2010-01-01

... damage-tolerance-based inspections and procedures for airplane structure susceptible to fatigue cracking... termed “fatigue critical structure.” (2) Adverse effects of repairs, alterations, and modifications. The..., and modifications may have on fatigue critical structure and on inspections required by paragraph (c...

Assessment of Modifications for Improving Navigation at Hilo Harbor, Hawaii

DTIC Science & Technology

2016-06-01

ER D C/ CH L TR -1 6- 9 Coastal Inlets Research Program Assessment of Modifications for Improving Navigation at Hilo Harbor, Hawaii...at http://acwc.sdp.sirsi.net/client/default. Coastal Inlets Research Program ERDC/CHL TR-16-9 June 2016 Assessment of Modifications for Improving...validation with 2013–2014 field data ................................................. 86 4.5.3 Chile tsunami effect on Hilo Harbor

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

Neitzel, D.A.; McKenzie, D.H.

To minimize adverse impact on aquatic ecosystems resulting from the operation of water intake structures, design engineers must have relevant information on the behavior, physiology and ecology of local fish and shellfish. Identification of stimulus/response relationships and the environmental factors that influence them is the first step in incorporating biological information in the design, location or modification of water intake structures. A procedure is presented in this document for providing biological input to engineers who are designing, locating or modifying a water intake structure. The authors discuss sources of stimuli at water intakes, historical approaches in assessing potential/actual impact andmore » review biological information needed for intake design.« less

Covalent modification of soy protein isolate by (-)-epigallocatechin-3-gallate: effects on structural and emulsifying properties.

PubMed

Tao, Fei; Jiang, He; Chen, Wenwei; Zhang, Yongyong; Pan, Jiarong; Jiang, Jiaxin; Jia, Zhenbao

2018-05-07

Soy protein isolate (SPI) has promising applications in various food products because of its excellent functional properties and nutritional quality. The structural and emulsifying properties of covalently modified SPI by (-)-epigallocatechin-3-gallate (EGCG) were investigated. SPI was covalently modified by EGCG under alkaline conditions. SDS-PAGE analysis revealed that EGCG modification caused cross-linking of SPI proteins. Circular dichroism spectra demonstrated that the secondary structure of SPI proteins was changed by EGCG modification. In addition, the modifications resulted in the perturbation of the tertiary structure of SPI as evidenced by intrinsic fluorescence spectra and surface hydrophobicity measurements. Oil-in-water emulsions of modified SPI had smaller droplet sizes and better creaming stability compared to those from unmodified SPI. The covalent modification by EGCG improved the emulsifying property of SPI. This study provided an innovative approach for improving the emulsifying properties of proteins. This article is protected by copyright. All rights reserved.

Sleep modifications in acute transient global amnesia.

PubMed

Della Marca, Giacomo; Mazza, Marianna; Losurdo, Anna; Testani, Elisa; Broccolini, Aldobrando; Frisullo, Giovanni; Marano, Giuseppe; Morosetti, Roberta; Pilato, Fabio; Profice, Paolo; Vollono, Catello; Di Lazzaro, Vincenzo

2013-09-15

Transient global amnesia (TGA) is a temporary memory loss characterized by an abrupt onset of antero-grade and retrograde amnesia, totally reversible. Since sleep plays a major role in memory consolidation, and in the storage of memory-related traces into the brain cortex, the aims of the present study were: (1) to evaluate changes in sleep macro-structure in TGA; (2) to assess modifications in sleep micro-structure in TGA, with particular reference to the arousal EEG and to cyclic alternating pattern (CAP); (3) to compare sleep parameters in TGA patients with a control group of patients with acute ischemic events ("minor stroke" or transient ischemic attack [TIA]) clinically and neuroradiologically "similar" to the TGA. TGA GROUP: 17 patients, (8 men and 9 women, 60.2 ± 12.5 years). Stroke or TIA (SoT) group: 17 patients hospitalized in the Stroke Unit for recent onset of minor stroke or TIA with hemispheric localization; healthy controls (HC) group: 17 healthy volunteers, matched for age and sex. Patients and controls underwent full-night polysomnography. In the multivariate analysis (conditions TGA, SoT, and HC) a significant effect of the condition was observed for sleep efficiency index, number of awakenings longer 1 min, REM latency, CAP time, and CAP rate. TGA and SoT differed only for CAP time and CAP rate, which were lower in the TGA group. Microstructural modification associated with tga could be consequent to: (1) hippocampal dysfunction and memory impairment; (2) impairment of arousal-related structures (in particular, cholinergic pathways); (3) emotional distress.

BPA-Induced Deregulation Of Epigenetic Patterns: Effects On Female Zebrafish Reproduction.

PubMed

Santangeli, Stefania; Maradonna, Francesca; Gioacchini, Giorgia; Cobellis, Gilda; Piccinetti, Chiara Carla; Dalla Valle, Luisa; Carnevali, Oliana

2016-02-25

Bisphenol A (BPA) is one of the commonest Endocrine Disruptor Compounds worldwide. It interferes with vertebrate reproduction, possibly by inducing deregulation of epigenetic mechanisms. To determine its effects on female reproductive physiology and investigate whether changes in the expression levels of genes related to reproduction are caused by histone modifications, BPA concentrations consistent with environmental exposure were administered to zebrafish for three weeks. Effects on oocyte growth and maturation, autophagy and apoptosis processes, histone modifications, and DNA methylation were assessed by Real-Time PCR (qPCR), histology, and chromatin immunoprecipitation combined with qPCR analysis (ChIP-qPCR). The results showed that 5 μg/L BPA down-regulated oocyte maturation-promoting signals, likely through changes in the chromatin structure mediated by histone modifications, and promoted apoptosis in mature follicles. These data indicate that the negative effects of BPA on the female reproductive system may be due to its upstream ability to deregulate epigenetic mechanism.

An efficient approach for the assembly of mass and stiffness matrices of structures with modifications

NASA Astrophysics Data System (ADS)

Wagner, Andreas; Spelsberg-Korspeter, Gottfried

2013-09-01

The finite element method is one of the most common tools for the comprehensive analysis of structures with applications reaching from static, often nonlinear stress-strain, to transient dynamic analyses. For single calculations the expense to generate an appropriate mesh is often insignificant compared to the analysis time even for complex geometries and therefore negligible. However, this is not the case for certain other applications, most notably structural optimization procedures, where the (re-)meshing effort is very important with respect to the total runtime of the procedure. Thus it is desirable to find methods to efficiently generate mass and stiffness matrices allowing to reduce this effort, especially for structures with modifications of minor complexity, e.g. panels with cutouts. Therefore, a modeling approach referred to as Energy Modification Method is proposed in this paper. The underlying idea is to model and discretize the basis structure, e.g. a plate, and the modifications, e.g. holes, separately. The discretized energy expressions of the modifications are then subtracted from (or added to) the energy expressions of the basis structure and the coordinates are related to each other by kinematical constraints leading to the mass and stiffness matrices of the complete structure. This approach will be demonstrated by two simple examples, a rod with varying material properties and a rectangular plate with a rectangular or circular hole, using a finite element discretization as basis. Convergence studies of the method based on the latter example follow demonstrating the rapid convergence and efficiency of the method. Finally, the Energy Modification Method is successfully used in the structural optimization of a circular plate with holes, with the objective to split all its double eigenfrequencies.

Vehicle Concept Model Abstractions For Integrated Geometric, Inertial ,Rigid Body, Powertrain and FE Analysis

DTIC Science & Technology

2011-06-17

structure through quantitative assessment of stiffness and modal parameter changes resulting from modifications to the beam geometries and positions...power transmission assembly. If the power limit at a wheel exceeds the traction limit, then depending on the type of differential placed on the axle ...components with appropriate model connectivity instead to determine the free modal response of powertrain type components, without abstraction

Vehicle Concept Model Abstractions for Integrated Geometric, Inertial, Rigid Body, Powertrain, and FE Analysis

DTIC Science & Technology

2011-01-01

refinement of the vehicle body structure through quantitative assessment of stiffness and modal parameter changes resulting from modifications to the beam...differential placed on the axle , adjustment of the torque output to the opposite wheel may be required to obtain the correct solution. Thus...represented by simple inertial components with appropriate model connectivity instead to determine the free modal response of powertrain type

Age-related carbonylation of fibrocartilage structural proteins drives tissue degenerative modification.

PubMed

Scharf, Brian; Clement, Cristina C; Yodmuang, Supansa; Urbanska, Aleksandra M; Suadicani, Sylvia O; Aphkhazava, David; Thi, Mia M; Perino, Giorgio; Hardin, John A; Cobelli, Neil; Vunjak-Novakovic, Gordana; Santambrogio, Laura

2013-07-25

Aging-related oxidative stress has been linked to degenerative modifications in different organs and tissues. Using redox proteomic analysis and illustrative tandem mass spectrometry mapping, we demonstrate oxidative posttranslational modifications in structural proteins of intervertebral discs (IVDs) isolated from aging mice. Increased protein carbonylation was associated with protein fragmentation and aggregation. Complementing these findings, a significant loss of elasticity and increased stiffness was measured in fibrocartilage from aging mice. Studies using circular dichroism and intrinsic tryptophan fluorescence revealed a significant loss of secondary and tertiary structures of purified collagens following oxidation. Collagen unfolding and oxidation promoted both nonenzymatic and enzymatic degradation. Importantly, induction of oxidative modification in healthy fibrocartilage recapitulated the biochemical and biophysical modifications observed in the aging IVD. Together, these results suggest that protein carbonylation, glycation, and lipoxidation could be early events in promoting IVD degenerative changes. Copyright © 2013 Elsevier Ltd. All rights reserved.

The impact of active controls technology on the structural integrity of aeronautical vehicles

NASA Technical Reports Server (NTRS)

Noll, Thomas E.; Austin, Edward; Donley, Shawn; Graham, George; Harris, Terry; Kaynes, Ian; Lee, Ben; Sparrow, James

1993-01-01

The findings of an investigation conducted under the auspices of The Technical Cooperation Program (TTCP) to assess the impact of active controls technology on the structural integrity of aeronautical vehicles and to evaluate the present state-of-the-art for predicting loads caused by a flight-control system modification and the resulting change in the fatigue life of the flight vehicle are summarized. Important points concerning structural technology considerations implicit in applying active controls technology in new aircraft are summarized. These points are well founded and based upon information received from within the aerospace industry and government laboratories, acquired by sponsoring workshops which brought together experts from contributing and interacting technical disciplines, and obtained by conducting a case study to independently assess the state of the technology. The paper concludes that communication between technical disciplines is absolutely essential in the design of future high performance aircraft.

An assessment of patient sign-outs conducted by University at Buffalo internal medicine residents.

PubMed

Wheat, Deirdre; Co, Christopher; Manochakian, Rami; Rich, Ellen

2012-01-01

Internal medicine residents were surveyed regarding patient sign-outs at shift change. Data were used to design and implement interventions aimed at improving sign-out quality. This quasi-experimental project incorporated the Plan, Do, Study, Act methodology. Residents completed an anonymous electronic survey regarding experiences during sign-outs. Survey questions assessed structure, process, and outcome of sign-outs. Analysis of qualitative and quantitative data was performed; interventions were implemented based on survey findings. A total of 120 surveys (89% response) and 115 surveys (83% response) were completed by residents of 4 postgraduate years in response to the first (2008) and second (2009) survey requests, respectively. Approximately 79% of the respondents to the second survey indicated that postintervention sign-out systems were superior to preintervention systems. Results indicated improvement in specific areas of structure, process, and outcome. Survey-based modifications to existing sign-out systems effected measurable quality improvement in structure, process, and outcome.

An Overview of Structurally Modified Glycyrrhetinic Acid Derivatives as Antitumor Agents.

PubMed

Xu, Bing; Wu, Gao-Rong; Zhang, Xin-Yu; Yan, Meng-Meng; Zhao, Rui; Xue, Nan-Nan; Fang, Kang; Wang, Hui; Chen, Meng; Guo, Wen-Bo; Wang, Peng-Long; Lei, Hai-Min

2017-06-02

Glycyrrhetinic Acid ( GA ), a triterpenoid aglycone component of the natural product glycyrrhizinic acid, was found to possess remarkable anti-proliferative and apoptosis-inducing activity in various cancer cell lines. Though GA was not as active as other triterpenes, such as betulinic acid and oleanolic acid, it could trigger apoptosis in tumor cells and it can be obtained easily and cheaply, which has stimulated scientific interest in using GA as a scaffold to synthesize new antitumor agents. The structural modifications of GA reported in recent decades can be divided into four groups, which include structural modifications on ring-A, ring-C, ring-E and multiple ring modifications. The lack of a comprehensive and recent review on this topic prompted us to gather more new information. This overview is dedicated to summarizing and updating the structural modification of GA to improve its antitumor activity published between 2005 and 2016. We reviewed a total of 210 GA derivatives that we encountered and compiled the most active GA derivatives along with their activity profile in different series. Furthermore, the structure activity relationships of these derivatives are briefly discussed. The included information is expected to be of benefit to further studies of structural modifications of GA to enhance its antitumor activity.

A knowledge-based patient assessment system: conceptual and technical design.

PubMed Central

Reilly, C. A.; Zielstorff, R. D.; Fox, R. L.; O'Connell, E. M.; Carroll, D. L.; Conley, K. A.; Fitzgerald, P.; Eng, T. K.; Martin, A.; Zidik, C. M.; Segal, M.

2000-01-01

This paper describes the design of an inpatient patient assessment application that captures nursing assessment data using a wireless laptop computer. The primary aim of this system is to capture structured information for facilitating decision support and quality monitoring. The system also aims to improve efficiency of recording patient assessments, reduce costs, and improve discharge planning and early identification of patient learning needs. Object-oriented methods were used to elicit functional requirements and to model the proposed system. A tools-based development approach is being used to facilitate rapid development and easy modification of assessment items and rules for decision support. Criteria for evaluation include perceived utility by clinician users, validity of decision support rules, time spent recording assessments, and perceived utility of aggregate reports for quality monitoring. PMID:11079970

A knowledge-based patient assessment system: conceptual and technical design.

PubMed

Reilly, C A; Zielstorff, R D; Fox, R L; O'Connell, E M; Carroll, D L; Conley, K A; Fitzgerald, P; Eng, T K; Martin, A; Zidik, C M; Segal, M

2000-01-01

This paper describes the design of an inpatient patient assessment application that captures nursing assessment data using a wireless laptop computer. The primary aim of this system is to capture structured information for facilitating decision support and quality monitoring. The system also aims to improve efficiency of recording patient assessments, reduce costs, and improve discharge planning and early identification of patient learning needs. Object-oriented methods were used to elicit functional requirements and to model the proposed system. A tools-based development approach is being used to facilitate rapid development and easy modification of assessment items and rules for decision support. Criteria for evaluation include perceived utility by clinician users, validity of decision support rules, time spent recording assessments, and perceived utility of aggregate reports for quality monitoring.

Assessment of Alphamagnetic Spectrometer (AMS) Upper Experiment Structural Configuration Shielding Effectiveness Associated with Change from Cryo-Cooled Magnet to Permanent Magnet

NASA Technical Reports Server (NTRS)

Scully, Robert

2012-01-01

In the spring of 2010, the Alpha Magnetic Spectrometer 2 (AMS-02) underwent a series of system level electromagnetic interference control measurements, followed by thermal vacuum testing. Shortly after completion of the thermal vacuum testing, the project decided to remove the cryogenically cooled superconducting magnet, and replace it with the original permanent magnet design employed in the earlier AMS- 01 assembly. Doing so necessitated several structural changes, as well as removal or modification of numerous electronic and thermal control devices and systems. At this stage, the project was rapidly approaching key milestone dates for hardware completion and delivery for launch, and had little time for additional testing or assessment of any impact to the electromagnetic signature of the AMS-02. Therefore, an analytical assessment of the radiated emissions behavioural changes associated with the system changes was requested.

Taurus II Stage Test Simulations: Using Large-Scale CFD Simulations to Provide Critical Insight into Plume Induced Environments During Design

NASA Technical Reports Server (NTRS)

Struzenberg, L. L.; West, J. S.

2011-01-01

This paper describes the use of targeted Loci/CHEM CFD simulations to evaluate the effects of a dual-engine first-stage hot-fire test on an evolving integrated launch pad/test article design. This effort was undertaken as a part of the NESC Independent Assessment of the Taurus II Stage Test Series. The underlying conceptual model included development of a series of computational models and simulations to analyze the plume induced environments on the pad, facility structures and test article. A pathfinder simulation was first developed, capable of providing quick-turn around evaluation of plume impingement pressures on the flame deflector. Results from this simulation were available in time to provide data for an ongoing structural assessment of the deflector. The resulting recommendation was available in a timely manner and was incorporated into construction schedule for the new launch stand under construction at Wallops Flight Facility. A series of Reynolds-Averaged Navier-Stokes (RANS) quasi-steady simulations representative of various key elements of the test profile was performed to identify potential concerns with the test configuration and test profile. As required, unsteady Hybrid-RANS/LES simulations were performed, to provide additional insight into critical aspects of the test sequence. Modifications to the test-specific hardware and facility structures thermal protection as well as modifications to the planned hot-fire test profile were implemented based on these simulation results.

Using the Modification Index and Standardized Expected Parameter Change for Model Modification

ERIC Educational Resources Information Center

Whittaker, Tiffany A.

2012-01-01

Model modification is oftentimes conducted after discovering a badly fitting structural equation model. During the modification process, the modification index (MI) and the standardized expected parameter change (SEPC) are 2 statistics that may be used to aid in the selection of parameters to add to a model to improve the fit. The purpose of this…

Modification of the supramolecular structure of collagen with nanodisperse hydroxyapatite

NASA Astrophysics Data System (ADS)

Voloskova, E. V.; Berdnikova, L. K.; Poluboyarov, V. A.; Gur'yanova, T. I.

2015-02-01

The influence of nanodisperse particles of hydroxyapatite on the structure of films based on collagen with a molecular mass of 360 kDa was studied. When coatings formed, the collagen macromolecules aggregated into spherulites; modification led to structural changes related to the decomposition of the spherulite structure and the formation of a grain structure. The variation of the physicomechanical properties of film materials directly depends on the size of the structural units.

Structural evaluation of a DTHR bundle divertor particle collector

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

Prevenslik, T.V.

1980-09-01

The purpose of this report is to present a structural evaluation of the current bundle divertor particle collector BDPC design under a peak heat flux in relation to criteria that protect against coolant leakage into the plasma over replacement schedules planned during DTHR operation. In addition, an assessment of the BDPC structural integrity at higher heat fluxes is presented. Further, recommendations for modifications in the current BDPC design that would improve design reliability to be considered in future design studies are described. Finally, experimental test programs directed to establishing materials data necessary in providing greater confidence in subsequent structural evaluationsmore » of BDPC designs in relation to coolant leakage over planned replacement schedules are identified.« less

[The psychometric properties of the new Turkish generic health-related quality of life questionnaire for children (Kid-KINDL)].

PubMed

Eser, Erhan; Yüksel, Hasan; Baydur, Hakan; Erhart, Michael; Saatli, Gül; Cengiz Ozyurt, Beyhan; Ozcan, Cemil; Ravens-Sieberer, Ulrike

2008-01-01

There are few health-related quality of life (HRQOL) instruments available that have been validated for use with Turkish children. The Kid-KINDL is a generic measure of children's (8-12 years) HRQOL, which contains 24 categorical items that assess 6 dimensions (physical well-being, emotional well-being, self-esteem, family, friends, and school). The Kid-KINDL is available in many languages. Following an elaborate translation procedure and cognitive focus group interviews, the Kid-KINDL was adopted into Turkish. This paper describes the psychometric properties of the new Turkish Kid-KINDL. In total, 1918 children aged 8-12 years at a school in Manisa completed the Kid-KINDL. A confirmatory approach was used for validity and reliability analysis. Using the Multi-trait/Multi-item analysis program (MAP) item-internal consistency and item-discriminant validity were calculated to confirm the instrument's structure. Likert scaling assumptions were tested and confirmatory factor analysis (CFA) was applied as well. After modification of 2 unsatisfactory items the Kid-KINDL was administered to a different group of 84 randomly selected children and the analyses were repeated. Cronbach's alpha was 0.35-0.78 before and 0.54-0.78 after the scales was modified. MAP-scaling success was 60%-100% before and 90%-100% after the modification. CFA confirmed the Kid-KINDL structure for the original version (RMSEA = 0.077) was less than the modified version (RMSEA = 0.059), although for the latter the sample was rather small. Floor effects were negligible, and ceiling effects reached 19%. The results indicate that the Turkish Kid-KINDL was a reliable and factorially valid assessment of the children's HRQOL. The modifications made to the 2 unsatisfactory items increased the psychometric quality of the scale.

Permit application modifications

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

NONE

1995-11-01

This document contains the Permit Application Modifications for the Y-12 Industrial Landfill V site on the Oak Ridge Reservation. These modifications include the assessment of stability of the proposed Landfill V under static and loading conditions. Analyses performed include the general slope stability, veneer stability of the bottom liner and cover system, and a liquefaction potential assessment of the foundation soils.

Biochemical and Structural Studies of RNA Modification and Repair

ERIC Educational Resources Information Center

Chan, Chio Mui

2009-01-01

RNA modification, RNA interference, and RNA repair are important events in the cell. This thesis presents three projects related to these three fields. By using both biochemical and structural methods, we characterized enzymatic activities of pseudouridine synthase TruD, solved the structure of "A. aeolicus" GidA, and reconstituted a novel…

Measuring quality of life in low-income, Spanish-speaking Puerto Ricans with type 2 diabetes residing in the mainland U.S.

PubMed

Lemon, Stephenie C; Rosal, Milagros C; Welch, Garry

2011-11-01

This study assessed the psychometric properties of the Audit of Diabetes-Dependent Quality of Life (ADDQoL) modified for low-income, low-education, Spanish-speaking Puerto Ricans with type 2 diabetes residing in the northeastern United States. Cross-sectional data from 226 patients were analyzed. Scale modifications included simplification of instructions, question wording and response format, and oral administration. Reliability was assessed with Cronbach's alpha coefficient and internal structure by exploratory factor analysis. Criterion validity was assessed using correlation analysis and linear and logistic regression models assessing the association of the ADDQoL with standardized physical health status, mental health status, depression, and comorbidity indices. Two ADDQoL items were dropped. The modified scale had excellent internal consistency and supported the original scale factor structure. Criterion validity results supported the validity of this measure. The modified ADDQoL showed psychometric properties that support its use in low-income, Spanish-speaking Puerto Ricans with type 2 diabetes who reside in mainland U.S.

Strategies for the profiling, characterisation and detailed structural analysis of N-linked oligosaccharides.

PubMed

Tharmalingam, Tharmala; Adamczyk, Barbara; Doherty, Margaret A; Royle, Louise; Rudd, Pauline M

2013-02-01

Many post-translational modifications, including glycosylation, are pivotal for the structural integrity, location and functional activity of glycoproteins. Sub-populations of proteins that are relocated or functionally changed by such modifications can change resting proteins into active ones, mediating specific effector functions, as in the case of monoclonal antibodies. To ensure safe and efficacious drugs it is essential to employ appropriate robust, quantitative analytical strategies that can (i) perform detailed glycan structural analysis, (ii) characterise specific subsets of glycans to assess known critical features of therapeutic activities (iii) rapidly profile glycan pools for at-line monitoring or high level batch to batch screening. Here we focus on these aspects of glycan analysis, showing how state-of-the-art technologies are required at all stages during the production of recombinant glycotherapeutics. These data can provide insights into processing pathways and suggest markers for intervention at critical control points in bioprocessing and also critical decision points in disease and drug monitoring in patients. Importantly, these tools are now enabling the first glycome/genome studies in large populations, allowing the integration of glycomics into other 'omics platforms in a systems biology context.

Brain Imaging and Human Nutrition: Which Measures to Use in Intervention Studies?12

PubMed Central

Sizonenko, Stéphane V.; Babiloni, Claudio; Sijben, John W.; Walhovd, Kristine B.

2013-01-01

Throughout the life span, the brain is a metabolically highly active organ that uses a large proportion of total nutrient and energy intake. Furthermore, the development and repair of neural tissue depend on the proper intake of essential structural nutrients, minerals, and vitamins. Therefore, what we eat, or refrain from eating, may have an important impact on our cognitive ability and mental performance. Two of the key areas in which diet is thought to play an important role are in optimizing neurodevelopment in children and in preventing neurodegeneration and cognitive decline during aging. From early development to aging, brain imaging can detect structural, functional, and metabolic changes in humans and modifications due to altered nutrition or to additional nutritional supplementation. Inclusion of imaging measures in clinical studies can increase understanding with regard to the modification of brain structure, metabolism, and functional endpoints and may provide early sensitive measures of long-term effects. In this symposium, the utility of existing brain imaging technologies to assess the effects of nutritional intervention in humans is described. Examples of current research showing the utility of these markers are reviewed. PMID:24038255

Immunocytochemical detection of astrocytes in brain slices in combination with Nissl staining.

PubMed

Korzhevskii, D E; Otellin, V A

2005-07-01

The present study was performed to develop a simple and reliable method for the combined staining of specimens to allow the advantages of immunocytochemical detection of astrocytes and assessment of the functional state of neurons by the Nissl method to be assessed simultaneously. The protocol suggested for processing paraffin sections allows preservation of tissue structure at high quality and allows the selective identification of astrocytes with counterstaining of neurons by the Nissl method. The protocol can be used without modification for processing brain specimens from humans and various mammals--except mice and rabbits.

C3I system modification and EMC (electromagnetic compatibility) methodology, volume 1

NASA Astrophysics Data System (ADS)

Wilson, J. L.; Jolly, M. B.

1984-01-01

A methodology (i.e., consistent set of procedures) for assessing the electromagnetic compatibility (EMC) of RF subsystem modifications on C3I aircraft was generated during this study (Volume 1). An IEMCAP (Intrasystem Electromagnetic Compatibility Analysis Program) database for the E-3A (AWACS) C3I aircraft RF subsystem was extracted to support the design of the EMC assessment methodology (Volume 2). Mock modifications were performed on the E-3A database to assess, using a preliminary form of the methodology, the resulting EMC impact. Application of the preliminary assessment methodology to modifications in the E-3A database served to fine tune the form of a final assessment methodology. The resulting final assessment methodology is documented in this report in conjunction with the overall study goals, procedures, and database. It is recommended that a similar EMC assessment methodology be developed for the power subsystem within C3I aircraft. It is further recommended that future EMC assessment methodologies be developed around expert systems (i.e., computer intelligent agents) to control both the excruciating detail and user requirement for transparency.

42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.

Code of Federal Regulations, 2011 CFR

2011-10-01

... prescribed exercise, cardiac risk factor modification, psychosocial assessment, and outcomes assessment... rehabilitation items and services are furnished. (ii) Cardiac risk factor modification, including education...

A tandem regression-outlier analysis of a ligand cellular system for key structural modifications around ligand binding.

PubMed

Lin, Ying-Ting

2013-04-30

A tandem technique of hard equipment is often used for the chemical analysis of a single cell to first isolate and then detect the wanted identities. The first part is the separation of wanted chemicals from the bulk of a cell; the second part is the actual detection of the important identities. To identify the key structural modifications around ligand binding, the present study aims to develop a counterpart of tandem technique for cheminformatics. A statistical regression and its outliers act as a computational technique for separation. A PPARγ (peroxisome proliferator-activated receptor gamma) agonist cellular system was subjected to such an investigation. Results show that this tandem regression-outlier analysis, or the prioritization of the context equations tagged with features of the outliers, is an effective regression technique of cheminformatics to detect key structural modifications, as well as their tendency of impact to ligand binding. The key structural modifications around ligand binding are effectively extracted or characterized out of cellular reactions. This is because molecular binding is the paramount factor in such ligand cellular system and key structural modifications around ligand binding are expected to create outliers. Therefore, such outliers can be captured by this tandem regression-outlier analysis.

Lactose-modified DNA tile nanostructures as drug carriers.

PubMed

Akkus Sut, Pinar; Tunc, Cansu Umran; Culha, Mustafa

2016-09-01

DNA hybridization allows the preparation of nanoscale DNA structures with desired shape and size. DNA structures using simple base pairing can be used for the delivery of drug molecules into the cells. Since DNA carries multiple negative charges, their cellular uptake efficiency is low. Thus, the modification of the DNA structures with molecules that may enhance the cellular internalization may be an option. The objective of this study is to construct DNA-based nanocarrier system and to investigate the cellular uptake of DNA tile with/without lactose modification. Doxorubicin was intercalated to DNA tile and cellular uptake of drug-loaded DNA-based carrier with/without lactose modification was investigated in vitro. HeLa, BT-474, and MDA-MB-231 cancer cells were used for cellular uptake studies and cytotoxicity assays. Using fluorescence spectroscopy, flow cytometry, and confocal microscopy, cellular uptake behavior of DNA tile was investigated. The cytotoxicity of DNA tile structures was determined with WST-1 assay. The results show that modification with lactose effectively increases the intracellular uptake of doxorubicin loaded DNA tile structure by cancer cells compared with the unmodified DNA tile. The findings of this study suggest that DNA-based nanostructures modified with carbohydrates can be used as suitable multifunctional nanocarriers with simple chemical modifications.

Loss of conformational stability in calmodulin upon methionine oxidation.

PubMed Central

Gao, J; Yin, D H; Yao, Y; Sun, H; Qin, Z; Schöneich, C; Williams, T D; Squier, T C

1998-01-01

We have used electrospray ionization mass spectrometry (ESI-MS), circular dichroism (CD), and fluorescence spectroscopy to investigate the secondary and tertiary structural consequences that result from oxidative modification of methionine residues in wheat germ calmodulin (CaM), and prevent activation of the plasma membrane Ca-ATPase. Using ESI-MS, we have measured rates of modification and molecular mass distributions of oxidatively modified CaM species (CaMox) resulting from exposure to H2O2. From these rates, we find that oxidative modification of methionine to the corresponding methionine sulfoxide does not predispose CaM to further oxidative modification. These results indicate that methionine oxidation results in no large-scale alterations in the tertiary structure of CaMox, because the rates of oxidative modification of individual methionines are directly related to their solvent exposure. Likewise, CD measurements indicate that methionine oxidation results in little change in the apparent alpha-helical content at 28 degrees C, and only a small (0.3 +/- 0.1 kcal mol(-1)) decrease in thermal stability, suggesting the disruption of a limited number of specific noncovalent interactions. Fluorescence lifetime, anisotropy, and quenching measurements of N-(1-pyrenyl)-maleimide (PMal) covalently bound to Cys26 indicate local structural changes around PMal in the amino-terminal domain in response to oxidative modification of methionine residues in the carboxyl-terminal domain. Because the opposing globular domains remain spatially distant in both native and oxidatively modified CaM, the oxidative modification of methionines in the carboxyl-terminal domain are suggested to modify the conformation of the amino-terminal domain through alterations in the structural features involving the interdomain central helix. The structural basis for the linkage between oxidative modification and these global conformational changes is discussed in terms of possible alterations in specific noncovalent interactions that have previously been suggested to stabilize the central helix in CaM. PMID:9512014

Ring structure modifications of phenylalanine 19 increase fibrillation kinetics and reduce toxicity of amyloid β (1-40).

PubMed

Korn, Alexander; Surendran, Dayana; Krueger, Martin; Maiti, Sudipta; Huster, Daniel

2018-05-24

We investigated the influence of the chemical structure of the phenylalanine side chain in position 19 of the 40 residue amyloid β peptide. Side chain modifications in this position yielded fibrils of essentially unaltered morphology, structure, and dynamics, but significantly increased fibrillation kinetics and diminished the toxicity of the peptides.

Sleep Modifications in Acute Transient Global Amnesia

PubMed Central

Della Marca, Giacomo; Mazza, Marianna; Losurdo, Anna; Testani, Elisa; Broccolini, Aldobrando; Frisullo, Giovanni; Marano, Giuseppe; Morosetti, Roberta; Pilato, Fabio; Profice, Paolo; Vollono, Catello; Di Lazzaro, Vincenzo

2013-01-01

Study Objective: Transient global amnesia (TGA) is a temporary memory loss characterized by an abrupt onset of antero-grade and retrograde amnesia, totally reversible. Since sleep plays a major role in memory consolidation, and in the storage of memory-related traces into the brain cortex, the aims of the present study were: (1) to evaluate changes in sleep macro-structure in TGA; (2) to assess modifications in sleep micro-structure in TGA, with particular reference to the arousal EEG and to cyclic alternating pattern (CAP); (3) to compare sleep parameters in TGA patients with a control group of patients with acute ischemic events (“minor stroke” or transient ischemic attack [TIA]) clinically and neuroradiologically “similar” to the TGA. Methods: TGA group: 17 patients, (8 men and 9 women, 60.2 ± 12.5 years). Stroke or TIA (SoT) group: 17 patients hospitalized in the Stroke Unit for recent onset of minor stroke or TIA with hemispheric localization; healthy controls (HC) group: 17 healthy volunteers, matched for age and sex. Patients and controls underwent full-night polysomnography. Results: In the multivariate analysis (conditions TGA, SoT, and HC) a significant effect of the condition was observed for sleep efficiency index, number of awakenings longer 1 min, REM latency, CAP time, and CAP rate. TGA and SoT differed only for CAP time and CAP rate, which were lower in the TGA group. Conclusions: Microstructural modification associated with TGA could be consequent to: (1) hippocampal dysfunction and memory impairment; (2) impairment of arousal-related structures (in particular, cholinergic pathways); (3) emotional distress. Citation: Della Marca G; Mazza M; Losurdo A; Testani E; Broccolini A; Frisullo G; Marano G; Morosetti R; Pilato F; Profice P; Vollono C; Di Lazzaro V. Sleep modifications in acute transient global amnesia. J Clin Sleep Med 2013;9(9):921-927. PMID:23997704

Raman-microscopy investigation of vitrification-induced structural damages in mature bovine oocytes

PubMed Central

De Canditiis, Carolina; Zito, Gianluigi; Rubessa, Marcello; Roca, Maria Serena; Carotenuto, Rosa; Sasso, Antonio; Gasparrini, Bianca

2017-01-01

Although oocyte cryopreservation has great potentials in the field of reproductive technologies, it still is an open challenge in the majority of domestic animals and little is known on the biochemical transformation induced by this process in the different cellular compartments. Raman micro-spectroscopy allows the non-invasive evaluation of the molecular composition of cells, based on the inelastic scattering of laser photons by vibrating molecules. The aim of this work was to assess the biochemical modifications of both the zona pellucida and cytoplasm of vitrified/warmed in vitro matured bovine oocytes at different post-warming times. By taking advantage of Principal Component Analysis, we were able to shed light on the biochemical transformation induced by the cryogenic treatment, also pointing out the specific role of cryoprotective agents (CPs). Our results suggest that vitrification induces a transformation of the protein secondary structure from the α-helices to the β-sheet form, while lipids tend to assume a more packed configuration in the zona pellucida. Both modifications result in a mechanical hardening of this cellular compartment, which could account for the reduced fertility rates of vitrified oocytes. Furthermore, biochemical modifications were observed at the cytoplasmic level in the protein secondary structure, with α-helices loss, suggesting cold protein denaturation. In addition, a decrease of lipid unsaturation was found in vitrified oocytes, suggesting oxidative damages. Interestingly, most modifications were not observed in oocytes exposed to CPs, suggesting that they do not severely affect the biochemical architecture of the oocyte. Nevertheless, in oocytes exposed to CPs decreased developmental competence and increased reactive oxygen species production were observed compared to the control. A more severe reduction of cleavage and blastocyst rates after in vitro fertilization was obtained from vitrified oocytes. Our experimental outcomes also suggest a certain degree of reversibility of the induced transformations, which renders vitrified oocytes more similar to untreated cells after 2 h warming. PMID:28531193

The Interaction between Epigenetics, Nutrition and the Development of Cancer

PubMed Central

Bishop, Karen S.; Ferguson, Lynnette R.

2015-01-01

Unlike the genome, the epigenome can be modified and hence some epigenetic risk markers have the potential to be reversed. Such modifications take place by means of drugs, diet or environmental exposures. It is widely accepted that epigenetic modifications take place during early embryonic and primordial cell development, but it is also important that we gain an understanding of the potential for such changes later in life. These “later life” epigenetic modifications in response to dietary intervention are the focus of this paper. The epigenetic modifications investigated include DNA methylation, histone modifications and the influence of microRNAs. The epigenotype could be used not only to predict susceptibility to certain cancers but also to assess the effectiveness of dietary modifications to reduce such risk. The influence of diet or dietary components on epigenetic modifications and the impact on cancer initiation or progression has been assessed herein. PMID:25647662

Structure solution of DNA-binding proteins and complexes with ARCIMBOLDO libraries

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

Pröpper, Kevin; Instituto de Biologia Molecular de Barcelona; Meindl, Kathrin

2014-06-01

The structure solution of DNA-binding protein structures and complexes based on the combination of location of DNA-binding protein motif fragments with density modification in a multi-solution frame is described. Protein–DNA interactions play a major role in all aspects of genetic activity within an organism, such as transcription, packaging, rearrangement, replication and repair. The molecular detail of protein–DNA interactions can be best visualized through crystallography, and structures emphasizing insight into the principles of binding and base-sequence recognition are essential to understanding the subtleties of the underlying mechanisms. An increasing number of high-quality DNA-binding protein structure determinations have been witnessed despite themore » fact that the crystallographic particularities of nucleic acids tend to pose specific challenges to methods primarily developed for proteins. Crystallographic structure solution of protein–DNA complexes therefore remains a challenging area that is in need of optimized experimental and computational methods. The potential of the structure-solution program ARCIMBOLDO for the solution of protein–DNA complexes has therefore been assessed. The method is based on the combination of locating small, very accurate fragments using the program Phaser and density modification with the program SHELXE. Whereas for typical proteins main-chain α-helices provide the ideal, almost ubiquitous, small fragments to start searches, in the case of DNA complexes the binding motifs and DNA double helix constitute suitable search fragments. The aim of this work is to provide an effective library of search fragments as well as to determine the optimal ARCIMBOLDO strategy for the solution of this class of structures.« less

Effect of glycation on α-crystallin structure and chaperone-like function

PubMed Central

Kumar, P. Anil; Kumar, M. Satish; Reddy, G. Bhanuprakash

2007-01-01

The chaperone-like activity of α-crystallin is considered to play an important role in the maintenance of the transparency of the eye lens. However, in the case of aging and in diabetes, the chaperone function of α-crystallin is compromized, resulting in cataract formation. Several post-translational modifications, including non-enzymatic glycation, have been shown to affect the chaperone function of α-crystallin in aging and in diabetes. A variety of agents have been identified as the predominant sources for the formation of AGEs (advanced glycation end-products) in various tissues, including the lens. Nevertheless, glycation of α-crystallin with various sugars has resulted in divergent results. In the present in vitro study, we have investigated the effect of glucose, fructose, G6P (glucose 6-phosphate) and MGO (methylglyoxal), which represent the major classes of glycating agents, on the structure and chaperone function of α-crystallin. Modification of α-crystallin with all four agents resulted in the formation of glycated protein, increased AGE fluorescence, protein cross-linking and HMM (high-molecular-mass) aggregation. Interestingly, these glycation-related profiles were found to vary with different glycating agents. For instance, CML [Nϵ-(carboxymethyl)lysine] was the predominant AGE formed upon glycation of α-crystallin with these agents. Although fructose and MGO caused significant conformational changes, there were no significant structural perturbations with glucose and G6P. With the exception of MGO modification, glycation with other sugars resulted in decreased chaperone activity in aggregation assays. However, modification with all four sugars led to the loss of chaperone activity as assessed using an enzyme inactivation assay. Glycation-induced loss of α-crystallin chaperone activity was associated with decreased hydrophobicity. Furthermore, α-crystallin isolated from glycated TSP (total lens soluble protein) had also increased AGE fluorescence, CML formation and diminished chaperone activity. These results indicate the susceptibility of α-crystallin to non-enzymatic glycation by various sugars and their derivatives, whose levels are elevated in diabetes. We also describes the effects of glycation on the structure and chaperone-like activity of α-crystallin. PMID:17696877

Incentive structure in team-based learning: graded versus ungraded Group Application exercises.

PubMed

Deardorff, Adam S; Moore, Jeremy A; McCormick, Colleen; Koles, Paul G; Borges, Nicole J

2014-04-21

Previous studies on team-based learning (TBL) in medical education demonstrated improved learner engagement, learner satisfaction, and academic performance; however, a paucity of information exists on modifications of the incentive structure of "traditional" TBL practices. The current study investigates the impact of modification to conventional Group Application exercises by examining student preference and student perceptions of TBL outcomes when Group Application exercises are excluded from TBL grades. During the 2009-2010 and 2010-2011 academic years, 175 students (95.6% response rate) completed a 22-item multiple choice survey followed by 3 open response questions at the end of their second year of medical school. These students had participated in a TBL supplemented preclinical curriculum with graded Group Application exercises during year one and ungraded Group Application exercises during year two of medical school. Chi-square analyses showed significant differences between grading categories for general assessment of TBL, participation and communication, intra-team discussion, inter-team discussion, student perceptions of their own effort and development of teamwork skills. Furthermore, 83.8% of students polled prefer ungraded Group Application exercises with only 7.2% preferring graded and 9.0% indicating no preference. The use of ungraded Group Application exercises appears to be a successful modification of TBL, making it more "student-friendly" while maintaining the goals of active learning and development of teamwork skills.

A Vastly Increased Chemical Variety of RNA Modifications Containing a Thioacetal Structure.

PubMed

Dal Magro, Christina; Keller, Patrick; Kotter, Annika; Werner, Stephan; Duarte, Victor; Marchand, Virginie; Ignarski, Michael; Freiwald, Anja; Müller, Roman-Ulrich; Dieterich, Christoph; Motorin, Yuri; Butter, Falk; Atta, Mohamed; Helm, Mark

2018-06-25

Recently discovered new chemical entities in RNA modifications have involved surprising functional groups that enlarge the chemical space of RNA. Using LC-MS, we found over 100 signals of RNA constituents that contained a ribose moiety in tRNAs from E. coli. Feeding experiments with variegated stable isotope labeled compounds identified 37 compounds that are new structures of RNA modifications. One structure was elucidated by deuterium exchange and high-resolution mass spectrometry. The structure of msms 2 i 6 A (2-methylthiomethylenethio-N6-isopentenyl-adenosine) was confirmed by methione-D3 feeding experiments and by synthesis of the nucleobase. The msms 2 i 6 A contains a thioacetal, shown in vitro to be biosynthetically derived from ms 2 i 6 A by the radical-SAM enzyme MiaB. This enzyme performs thiomethylation, forming ms 2 i 6 A from i 6 A in a first turnover. The new thioacetal is formed by a second turnover. Along with the pool of 36 new modifications, this work describes a new layer of RNA modification chemistry. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analytical and functional similarity of Amgen biosimilar ABP 215 to bevacizumab.

PubMed

Seo, Neungseon; Polozova, Alla; Zhang, Mingxuan; Yates, Zachary; Cao, Shawn; Li, Huimin; Kuhns, Scott; Maher, Gwendolyn; McBride, Helen J; Liu, Jennifer

ABP 215 is a biosimilar product to bevacizumab. Bevacizumab acts by binding to vascular endothelial growth factor A, inhibiting endothelial cell proliferation and new blood vessel formation, thereby leading to tumor vasculature normalization. The ABP 215 analytical similarity assessment was designed to assess the structural and functional similarity of ABP 215 and bevacizumab sourced from both the United States (US) and the European Union (EU). Similarity assessment was also made between the US- and EU-sourced bevacizumab to assess the similarity between the two products. The physicochemical properties and structural similarity of ABP 215 and bevacizumab were characterized using sensitive state-of-the-art analytical techniques capable of detecting small differences in product attributes. ABP 215 has the same amino acid sequence and exhibits similar post-translational modification profiles compared to bevacizumab. The functional similarity assessment employed orthogonal assays designed to interrogate all expected biological activities, including those known to affect the mechanisms of action for ABP 215 and bevacizumab. More than 20 batches of bevacizumab (US) and bevacizumab (EU), and 13 batches of ABP 215 representing unique drug substance lots were assessed for similarity. The large dataset allows meaningful comparisons and garners confidence in the overall conclusion for the analytical similarity assessment of ABP 215 to both US- and EU-sourced bevacizumab. The structural and purity attributes, and biological properties of ABP 215 are demonstrated to be highly similar to those of bevacizumab.

Development of a theory-based questionnaire to assess structure and control in parent feeding (SCPF).

PubMed

Savage, Jennifer S; Rollins, Brandi Y; Kugler, Kari C; Birch, Leann L; Marini, Michele E

2017-01-26

Parents shape children's eating environments and act as powerful socialization agents, impacting young children's behavioral controls of food intake. Most feeding measures assess parents' use of control to manage children's intake of energy dense foods. The Structure and Control in Parent Feeding (SCPF) questionnaire was developed to assess more positive aspects of feeding practices with their young children -setting limits, providing routines-that promote self-regulation, as well as controlling feeding practices. A mixed method approach was used to develop the SCPF. In 2013, cognitive interviews informed the modification, deletion and/or replacement of items. In 2014, the survey was distributed statewide to mothers of toddlers aged 12 to 36 months participating in the Women, Infants, and Children program. In 2016, exploratory factor analyses was conducted to test our theoretical parenting model and content validity and criterion validity were assessed (n = 334). Exploratory factor analysis (EFA) and second-order EFA revealed a 2-factor, 22-item Structure model and a 2-factor, 12-item Control model. Internal consistencies for all factors exceeded 0.70. As predicted, the Structure superfactor was positivity associated with responsiveness, whereas the Control superfactor was positively associated with demandingness on the Caregiver's Feeding Styles Questionnaire. The Structure subscales were also positively associated with mealtime behaviors and Control subscales were positively associated with control-oriented feeding measures from the Control in Parent Feeding Practices questionnaire. The SCPF questionnaire is a reliable tool that can be used to assess aspects of structure- and control-based feeding practices to better understand how parents feed their toddlers.

Resilience of biochemical activity in protein domains in the face of structural divergence.

PubMed

Zhang, Dapeng; Iyer, Lakshminarayan M; Burroughs, A Maxwell; Aravind, L

2014-06-01

Recent studies point to the prevalence of the evolutionary phenomenon of drastic structural transformation of protein domains while continuing to preserve their basic biochemical function. These transformations span a wide spectrum, including simple domains incorporated into larger structural scaffolds, changes in the structural core, major active site shifts, topological rewiring and extensive structural transmogrifications. Proteins from biological conflict systems, such as toxin-antitoxin, restriction-modification, CRISPR/Cas, polymorphic toxin and secondary metabolism systems commonly display such transformations. These include endoDNases, metal-independent RNases, deaminases, ADP ribosyltransferases, immunity proteins, kinases and E1-like enzymes. In eukaryotes such transformations are seen in domains involved in chromatin-related peptide recognition and protein/DNA-modification. Intense selective pressures from 'arms-race'-like situations in conflict and macromolecular modification systems could favor drastic structural divergence while preserving function. Published by Elsevier Ltd.

Structure and functional properties of TiNiZr surface layers obtained by high-velocity oxygen fuel spraying

NASA Astrophysics Data System (ADS)

Rusinov, P. O.; Blednova, Zh M.; Borovets, O. I.

2017-05-01

The authors studied a complex method of surface modification of steels for materials with shape memory effect (SME) Ti-Ni-Zr with a high-velocity oxygen-fuel spraying (HVOF) of mechanically activated (MA) powder in a protective medium. We assessed the functional properties and X-ray diffraction studies, which showed that the formation of surface layers according to the developed technology ensures the manifestation of the shape memory effect.

Food structure: Its formation and relationships with other properties.

PubMed

Joardder, Mohammad U H; Kumar, Chandan; Karim, M A

2017-04-13

Food materials are complex in nature as it has heterogeneous, amorphous, hygroscopic and porous properties. During processing, microstructure of food materials changes which significantly affects other properties of food. An appropriate understanding of the microstructure of the raw food material and its evolution during processing is critical in order to understand and accurately describe dehydration processes and quality anticipation. This review critically assesses the factors that influence the modification of microstructure in the course of drying of fruits and vegetables. The effect of simultaneous heat and mass transfer on microstructure in various drying methods is investigated. Effects of changes in microstructure on other functional properties of dried foods are discussed. After an extensive review of the literature, it is found that development of food structure significantly depends on fresh food properties and process parameters. Also, modification of microstructure influences the other properties of final product. An enhanced understanding of the relationships between food microstructure, drying process parameters and final product quality will facilitate the energy efficient optimum design of the food processor in order to achieve high-quality food.

A rational approach to predict and modulate stereolability of chiral alpha substituted ketones.

PubMed

Cirilli, Roberto; Costi, Roberta; Di Santo, Roberto; Gasparrini, Francesco; La Torre, Francesco; Pierini, Marco; Siani, Gabriella

2009-01-01

An effective strategy to assess and modulate the stereolability of chiral alpha substituted ketones (C alpha SKs) is presented. The tendency of C alpha SKs to retain or change their configuration in water is analyzed as a function of thermodynamic proton-release attitude of alpha asymmetric atoms inside the structures by linear Brønsted correlations. A molecular modeling procedure was developed to analyze and suggest chemical modifications of C alpha SKs in view to obtain the desired grade of stereochemical stability. The approach was employed to predict the tendency to enantiomerize in water of two ketones (1 and 2) endowed with inhibitory activity against monoamine oxidases (MAOs) and the results were confirmed by experimental kinetics measurements performed in organic medium. As a demonstration of practical potentialities of the approach, four new structures, conceived as simple chemical modifications of 1 and 2, were designed to improve/reduce the stereostability grade of the starting anti-MAO ketones. The possibility to extend easily the procedure to other classes of C-H acids appears of interest.

Effects of cytoskeletal disruption on transport, structure, and rheology within mammalian cells

PubMed Central

Weihs, Daphne; Mason, Thomas G.; Teitell, Michael A.

2009-01-01

Quantification of cellular responses to stimuli is challenging. Cells respond to changing external conditions through internal structural and compositional and functional modifications, thereby altering their transport and mechanical properties. By properly interpreting particle-tracking microrheology, we evaluate the response of live cells to cytoskeletal disruption mediated by the drug nocodazole. Prior to administering the drug, the particles exhibit an apparently diffusive behavior that is actually a combination of temporally heterogeneous ballistic and caged motion. Selectively depolymerizing microtubules with the drug causes actively crawling cells to halt, providing a means for assessing drug efficacy, and making the caged motion of the probes readily apparent. PMID:19816550

Enhancements to AERMOD's building downwash algorithms based on wind-tunnel and Embedded-LES modeling

NASA Astrophysics Data System (ADS)

Monbureau, E. M.; Heist, D. K.; Perry, S. G.; Brouwer, L. H.; Foroutan, H.; Tang, W.

2018-04-01

Knowing the fate of effluent from an industrial stack is important for assessing its impact on human health. AERMOD is one of several Gaussian plume models containing algorithms to evaluate the effect of buildings on the movement of the effluent from a stack. The goal of this study is to improve AERMOD's ability to accurately model important and complex building downwash scenarios by incorporating knowledge gained from a recently completed series of wind tunnel studies and complementary large eddy simulations of flow and dispersion around simple structures for a variety of building dimensions, stack locations, stack heights, and wind angles. This study presents three modifications to the building downwash algorithm in AERMOD that improve the physical basis and internal consistency of the model, and one modification to AERMOD's building pre-processor to better represent elongated buildings in oblique winds. These modifications are demonstrated to improve the ability of AERMOD to model observed ground-level concentrations in the vicinity of a building for the variety of conditions examined in the wind tunnel and numerical studies.

Crosslinking Protein Glutathionylation Mediated by O2-Arylated Bis-Diazeniumdiolate “Double JS-K”

PubMed Central

Holland, Ryan J.; Maciag, Anna E.; Kumar, Varun; Shi, Lei; Saavedra, Joseph E.; Prud’homme, Robert K.; Chakrapani, Harinath; Keefer, Larry K.

2012-01-01

Attachment of glutathione (GSH) to cysteine residues in proteins (S-glutathionylation) is a reversible post-translational modification that can profoundly alter protein structure and function. Often serving in a protective role, e.g., by temporarily saving protein thiols from irreversible oxidation and inactivation, glutathionylation can be identified and semi-quantitatively assessed using anti-GSH antibodies, thought to be specific for recognition of the S-glutathionylation modification. Here we describe an alternate mechanism of protein glutathionylation in which the sulfur atoms of the GSH and the protein’s thiol group are covalently bound via a crosslinking agent, rather than through a disulfide bond. This form of thiol crosslinking has been shown to occur and confirmed by mass spectrometry at the solution chemistry level, as well as in experiments documenting the potent antiproliferative activity of the bis-diazeniumdiolate Double JS-K in H1703 cells in vitro and in vivo. The modification is recognized by the anti-GSH antibody as if it were authentic S-glutathionylation, requiring mass spectrometry to distinguish between them. PMID:23106594

Favorable 2'-substitution in the loop region of a thrombin-binding DNA aptamer.

PubMed

Awachat, Ragini; Wagh, Atish A; Aher, Manisha; Fernandes, Moneesha; Kumar, Vaijayanti A

2018-06-01

Simple 2'-OMe-chemical modification in the loop region of the 15mer G-rich DNA sequence GGTTGGTGTGGTTGG is reported. The G-quadruplex structure of this thrombin-binding aptamer (TBA), is stabilized by single modifications (T → 2'-OMe-U), depending on the position of the modification. The structural stability also renders significantly increased inhibition of thrombin-induced fibrin polymerization, a process closely associated with blood-clotting. Copyright © 2018 Elsevier Ltd. All rights reserved.

Laser patterning of platinum electrodes for safe neurostimulation

NASA Astrophysics Data System (ADS)

Green, R. A.; Matteucci, P. B.; Dodds, C. W. D.; Palmer, J.; Dueck, W. F.; Hassarati, R. T.; Byrnes-Preston, P. J.; Lovell, N. H.; Suaning, G. J.

2014-10-01

Objective. Laser surface modification of platinum (Pt) electrodes was investigated for use in neuroprosthetics. Surface modification was applied to increase the surface area of the electrode and improve its ability to transfer charge within safe electrochemical stimulation limits. Approach. Electrode arrays were laser micromachined to produce Pt electrodes with smooth surfaces, which were then modified with four laser patterning techniques to produce surface structures which were nanosecond patterned, square profile, triangular profile and roughened on the micron scale through structured laser interference patterning (SLIP). Improvements in charge transfer were shown through electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and biphasic stimulation at clinically relevant levels. A new method was investigated and validated which enabled the assessment of in vivo electrochemically safe charge injection limits. Main results. All of the modified surfaces provided electrical advantage over the smooth Pt. The SLIP surface provided the greatest benefit both in vitro and in vivo, and this surface was the only type which had injection limits above the threshold for neural stimulation, at a level shown to produce a response in the feline visual cortex when using an electrode array implanted in the suprachoroidal space of the eye. This surface was found to be stable when stimulated with more than 150 million clinically relevant pulses in physiological saline. Significance. Critical to the assessment of implant devices is accurate determination of safe usage limits in an in vivo environment. Laser patterning, in particular SLIP, is a superior technique for improving the performance of implant electrodes without altering the interfacial electrode chemistry through coating. Future work will require chronic in vivo assessment of these electrode patterns.

Yttria-stabilized zirconia solid oxide electrolyte fuel cells: Monolithic solid oxide fuel cells

NASA Astrophysics Data System (ADS)

1990-10-01

The monolithic solid oxide fuel cell (MSOFC) is currently under development for a variety of applications including coal-based power generation. The MSOFC is a design concept that places the thin components of a solid oxide fuel cell in lightweight, compact, corrugated structure, and so achieves high efficiency and excellent performance simultaneously with high power density. The MSOFC can be integrated with coal gasification plants and is expected to have high overall efficiency in the conversion of the chemical energy of coal to electrical energy. This report describes work aimed at: (1) assessing manufacturing costs for the MSOFC and system costs for a coal-based plant; (2) modifying electrodes and electrode/electrolyte interfaces to improve the electrochemical performance of the MSOFC; and (3) testing the performance of the MSOFC on hydrogen and simulated coal gas. Manufacturing costs for both the coflow and crossflow MSOFC's were assessed based on the fabrication flow charts developed by direct scaleup of tape calendering and other laboratory processes. Integrated coal-based MSOFC systems were investigated to determine capital costs and costs of electricity. Design criteria were established for a coal-fueled 200-Mw power plant. Four plant arrangements were evaluated, and plant performance was analyzed. Interfacial modification involved modification of electrodes and electrode/electrolyte interfaces to improve the MSOFC electrochemical performance. Work in the cathode and cathode/electrolyte interface was concentrated on modification of electrode porosity, electrode morphology, electrode material, and interfacial bonding. Modifications of the anode and anode/electrolyte interface included the use of additives and improvement of nickel distribution. Single cells have been tested for their electrochemical performance. Performance data were typically obtained with humidified H2 or simulated coal gas and air or oxygen.

Epigenomic landscape modified by histone modification correlated with activation of IGF2 gene

USDA-ARS?s Scientific Manuscript database

The links of histone post-translational modifications and chromatin structure to cell cycle progression, DNA replication, and overall chromosome functions are very clear. The modulation of genome expression as a consequence of chromatin structural changes is most likely a basic mechanism. The epige...

An Empirical Comparison of Competing Factor Structures for the Repeatable Battery for the Assessment of Neuropsychological Status: A Project FRONTIER Study†

PubMed Central

Torrence, Nicole D.; John, Samantha E.; Gavett, Brandon E.; O'Bryant, Sid E.

2016-01-01

The original factor structure of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has received little empirical support, but at least eight alternative factor structures have been identified in the literature. The current study used confirmatory factor analysis to compare the original RBANS model with eight alternatives, which were adjusted to include a general factor. Participant data were obtained from Project FRONTIER, an epidemiological study of rural health, and comprised 341 adults (229 women, 112 men) with mean age of 61.2 years (SD = 12.1) and mean education of 12.4 years (SD = 3.3). A bifactor version of the model proposed by Duff and colleagues provided the best fit to the data (CFI = 0.98; root-mean-squared error of approximation = 0.07), but required further modification to produce appropriate factor loadings. The results support the inclusion of a general factor and provide partial replication of the Duff and colleagues RBANS model. PMID:26429558

Reverse osmosis membrane composition, structure and performance modification by bisulphite, iron(III), bromide and chlorite exposure.

PubMed

Ferrer, O; Gibert, O; Cortina, J L

2016-10-15

Reverse osmosis (RO) membrane exposure to bisulphite, chlorite, bromide and iron(III) was assessed in terms of membrane composition, structure and performance. Membrane composition was determined by Rutherford backscattering spectrometry (RBS) and membrane performance was assessed by water and chloride permeation, using a modified version of the solution-diffusion model. Iron(III) dosage in presence of bisulphite led to an autooxidation of the latter, probably generating free radicals which damaged the membrane. It comprised a significant raise in chloride passage (chloride permeation coefficient increased 5.3-5.1 fold compared to the virgin membrane under the conditions studied) rapidly. No major differences in terms of water permeability and membrane composition were observed. Nevertheless, an increase in the size of the network pores, and a raise in the fraction of aggregate pores of the polyamide (PA) layer were identified, but no amide bond cleavage was observed. These structural changes were therefore, in accordance with the transport properties observed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Detecting the impact of bank and channel modification on invertebrate communities in Mediterranean temporary streams (Sardinia, SW Italy).

PubMed

Buffagni, Andrea; Tenchini, Roberta; Cazzola, Marcello; Erba, Stefania; Balestrini, Raffaella; Belfiore, Carlo; Pagnotta, Romano

2016-09-15

We hypothesized that reach-scale, bank and channel modification would impact benthic communities in temporary rivers of Sardinia, when pollution and water abstraction are not relevant. A range of variables were considered, which include both artificial structures/alterations and natural features observed in a stream reach. Multivariate regression trees (MRT) were used to assess the effects of the explanatory variables on invertebrate assemblages and five groups, characterized by different habitat modification and/or features, were recognized. Four node variables determined the splits in the MRT analysis: channel reinforcement, tree-related bank and channel habitats, channel modification and bank modification. Continuity of trees in the river corridor diverged among MRT groups and significant differences among groups include presence of alders, extent of channel shading and substrate diversity. Also, the percentage of in-stream organic substrates, in particular CPOM/Xylal, showed highly significant differences among groups. For practical applications, thresholds for the extent of channel reinforcement (40%) and modification (10%) and for bank alteration (≈30%) were provided, that can be used to guide the implementation of restoration measures. In moderately altered river reaches, a significant extent of tree-related habitats (≈5%) can noticeably mitigate the effects of morphological alteration on aquatic invertebrates. The outcomes highlight the importance of riparian zone management as an opportune, achievable prospect in the restoration of Mediterranean temporary streams. The impact of bank and channel modification on ecological status (sensu WFD) was investigated and the tested benthic metrics, especially those based on abundance data, showed legible differences among MRT groups. Finally, bank and channel modification appears to be a potential threat for the conservation of a few Sardo-Corsican endemic species. The introduction of management criteria that openly use information on endemic species seems crucial to reduce the risk of improving overall ecological status while depleting biodiversity. Copyright © 2016 Elsevier B.V. All rights reserved.

Sonic hedgehog multimerization: a self-organizing event driven by post-translational modifications?

PubMed

Koleva, Mirella V; Rothery, Stephen; Spitaler, Martin; Neil, Mark A A; Magee, Anthony I

2015-01-01

Sonic hedgehog (Shh) is a morphogen active during vertebrate development and tissue homeostasis in adulthood. Dysregulation of the Shh signalling pathway is known to incite carcinogenesis. Due to the highly lipophilic nature of this protein imparted by two post-translational modifications, Shh's method of transit through the aqueous extracellular milieu has been a long-standing conundrum, prompting the proposition of numerous hypotheses to explain the manner of its displacement from the surface of the producing cell. Detection of high molecular-weight complexes of Shh in the intercellular environment has indicated that the protein achieves this by accumulating into multimeric structures prior to release from producing cells. The mechanism of assembly of the multimers, however, has hitherto remained mysterious and contentious. Here, with the aid of high-resolution optical imaging and post-translational modification mutants of Shh, we show that the C-terminal cholesterol and the N-terminal palmitate adducts contribute to the assembly of large multimers and regulate their shape. Moreover, we show that small Shh multimers are produced in the absence of any lipid modifications. Based on an assessment of the distribution of various dimensional characteristics of individual Shh clusters, in parallel with deductions about the kinetics of release of the protein from the producing cells, we conclude that multimerization is driven by self-assembly underpinned by the law of mass action. We speculate that the lipid modifications augment the size of the multimolecular complexes through prolonging their association with the exoplasmic membrane.

Hydrogen bond formation between the naturally modified nucleobase and phosphate backbone

PubMed Central

Sheng, Jia; Zhang, Wen; Hassan, Abdalla E. A.; Gan, Jianhua; Soares, Alexei S.; Geng, Song; Ren, Yi; Huang, Zhen

2012-01-01

Natural RNAs, especially tRNAs, are extensively modified to tailor structure and function diversities. Uracil is the most modified nucleobase among all natural nucleobases. Interestingly, >76% of uracil modifications are located on its 5-position. We have investigated the natural 5-methoxy (5-O-CH3) modification of uracil in the context of A-form oligonucleotide duplex. Our X-ray crystal structure indicates first a H-bond formation between the uracil 5-O-CH3 and its 5′-phosphate. This novel H-bond is not observed when the oxygen of 5-O-CH3 is replaced with a larger atom (selenium or sulfur). The 5-O-CH3 modification does not cause significant structure and stability alterations. Moreover, our computational study is consistent with the experimental observation. The investigation on the uracil 5-position demonstrates the importance of this RNA modification at the atomic level. Our finding suggests a general interaction between the nucleobase and backbone and reveals a plausible function of the tRNA 5-O-CH3 modification, which might potentially rigidify the local conformation and facilitates translation. PMID:22641848

The computational nature of memory modification.

PubMed

Gershman, Samuel J; Monfils, Marie-H; Norman, Kenneth A; Niv, Yael

2017-03-15

Retrieving a memory can modify its influence on subsequent behavior. We develop a computational theory of memory modification, according to which modification of a memory trace occurs through classical associative learning, but which memory trace is eligible for modification depends on a structure learning mechanism that discovers the units of association by segmenting the stream of experience into statistically distinct clusters (latent causes). New memories are formed when the structure learning mechanism infers that a new latent cause underlies current sensory observations. By the same token, old memories are modified when old and new sensory observations are inferred to have been generated by the same latent cause. We derive this framework from probabilistic principles, and present a computational implementation. Simulations demonstrate that our model can reproduce the major experimental findings from studies of memory modification in the Pavlovian conditioning literature.

Cost Savings Potential of Modification to the Standard Light Rail Vehicle Specification

DOT National Transportation Integrated Search

1979-02-01

This report describes an assessment of the Standard Light Rail Vehicle (SLRV) specification to determine whether the relaxation or modification of some requirements could result in a significant reduction in vehicle costs. A Technique of Assessment b...

Quality assessment of protein model-structures based on structural and functional similarities.

PubMed

Konopka, Bogumil M; Nebel, Jean-Christophe; Kotulska, Malgorzata

2012-09-21

Experimental determination of protein 3D structures is expensive, time consuming and sometimes impossible. A gap between number of protein structures deposited in the World Wide Protein Data Bank and the number of sequenced proteins constantly broadens. Computational modeling is deemed to be one of the ways to deal with the problem. Although protein 3D structure prediction is a difficult task, many tools are available. These tools can model it from a sequence or partial structural information, e.g. contact maps. Consequently, biologists have the ability to generate automatically a putative 3D structure model of any protein. However, the main issue becomes evaluation of the model quality, which is one of the most important challenges of structural biology. GOBA--Gene Ontology-Based Assessment is a novel Protein Model Quality Assessment Program. It estimates the compatibility between a model-structure and its expected function. GOBA is based on the assumption that a high quality model is expected to be structurally similar to proteins functionally similar to the prediction target. Whereas DALI is used to measure structure similarity, protein functional similarity is quantified using standardized and hierarchical description of proteins provided by Gene Ontology combined with Wang's algorithm for calculating semantic similarity. Two approaches are proposed to express the quality of protein model-structures. One is a single model quality assessment method, the other is its modification, which provides a relative measure of model quality. Exhaustive evaluation is performed on data sets of model-structures submitted to the CASP8 and CASP9 contests. The validation shows that the method is able to discriminate between good and bad model-structures. The best of tested GOBA scores achieved 0.74 and 0.8 as a mean Pearson correlation to the observed quality of models in our CASP8 and CASP9-based validation sets. GOBA also obtained the best result for two targets of CASP8, and one of CASP9, compared to the contest participants. Consequently, GOBA offers a novel single model quality assessment program that addresses the practical needs of biologists. In conjunction with other Model Quality Assessment Programs (MQAPs), it would prove useful for the evaluation of single protein models.

A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties.

PubMed

Dastjerdi, Roya; Montazer, Majid

2010-08-01

Textiles can provide a suitable substrate to grow micro-organisms especially at appropriate humidity and temperature in contact to human body. Recently, increasing public concern about hygiene has been driving many investigations for anti-microbial modification of textiles. However, using many anti-microbial agents has been avoided because of their possible harmful or toxic effects. Application of inorganic nano-particles and their nano-composites would be a good alternative. This review paper has focused on the properties and applications of inorganic nano-structured materials with good anti-microbial activity potential for textile modification. The discussed nano-structured anti-microbial agents include TiO(2) nano-particles, metallic and non-metallic TiO(2) nano-composites, titania nanotubes (TNTs), silver nano-particles, silver-based nano-structured materials, gold nano-particles, zinc oxide nano-particles and nano-rods, copper nano-particles, carbon nanotubes (CNTs), nano-clay and its modified forms, gallium, liposomes loaded nano-particles, metallic and inorganic dendrimers nano-composite, nano-capsules and cyclodextrins containing nano-particles. This review is also concerned with the application methods for the modification of textiles using nano-structured materials. Copyright 2010 Elsevier B.V. All rights reserved.

Iterative model building, structure refinement and density modification with the PHENIX AutoBuild wizard.

PubMed

Terwilliger, Thomas C; Grosse-Kunstleve, Ralf W; Afonine, Pavel V; Moriarty, Nigel W; Zwart, Peter H; Hung, Li Wei; Read, Randy J; Adams, Paul D

2008-01-01

The PHENIX AutoBuild wizard is a highly automated tool for iterative model building, structure refinement and density modification using RESOLVE model building, RESOLVE statistical density modification and phenix.refine structure refinement. Recent advances in the AutoBuild wizard and phenix.refine include automated detection and application of NCS from models as they are built, extensive model-completion algorithms and automated solvent-molecule picking. Model-completion algorithms in the AutoBuild wizard include loop building, crossovers between chains in different models of a structure and side-chain optimization. The AutoBuild wizard has been applied to a set of 48 structures at resolutions ranging from 1.1 to 3.2 A, resulting in a mean R factor of 0.24 and a mean free R factor of 0.29. The R factor of the final model is dependent on the quality of the starting electron density and is relatively independent of resolution.

Diet Modification for Hyperlipidemia

PubMed Central

Mann, Heather D.; Piotrowski, Pamela

1992-01-01

Hyperlipidemia is a major risk factor associated with cardiovascular disease. Dietary modification is effective in achieving and maintaining improved serum lipid levels. Nutritional care provided by a dietitian includes individual dietary and lifestyle assessment, formulating an appropriate dietary regimen, education, and follow-up assessments. PMID:21221406

Subtractive Structural Modification of Morpho Butterfly Wings.

PubMed

Shen, Qingchen; He, Jiaqing; Ni, Mengtian; Song, Chengyi; Zhou, Lingye; Hu, Hang; Zhang, Ruoxi; Luo, Zhen; Wang, Ge; Tao, Peng; Deng, Tao; Shang, Wen

2015-11-11

Different from studies of butterfly wings through additive modification, this work for the first time studies the property change of butterfly wings through subtractive modification using oxygen plasma etching. The controlled modification of butterfly wings through such subtractive process results in gradual change of the optical properties, and helps the further understanding of structural optimization through natural evolution. The brilliant color of Morpho butterfly wings is originated from the hierarchical nanostructure on the wing scales. Such nanoarchitecture has attracted a lot of research effort, including the study of its optical properties, its potential use in sensing and infrared imaging, and also the use of such structure as template for the fabrication of high-performance photocatalytic materials. The controlled subtractive processes provide a new path to modify such nanoarchitecture and its optical property. Distinct from previous studies on the optical property of the Morpho wing structure, this study provides additional experimental evidence for the origination of the optical property of the natural butterfly wing scales. The study also offers a facile approach to generate new 3D nanostructures using butterfly wings as the templates and may lead to simpler structure models for large-scale man-made structures than those offered by original butterfly wings. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurement Invariance of the Internet Gaming Disorder Scale-Short-Form (IGDS9-SF) between the United States of America, India and the United Kingdom.

PubMed

Pontes, Halley M; Stavropoulos, Vasileios; Griffiths, Mark D

2017-11-01

The Internet Gaming Disorder Scale-Short-Form (IGDS9-SF) has been extensively used worldwide to assess Internet Gaming Disorder (IGD) behaviors. Therefore, investigating cultural limitations and implications in its applicability is necessary. The cross-cultural feasibility of a test can be psychometrically evaluated with measurement invariance analyses. Thus, the present study used Multigroup Confirmatory Factor Analysis (MGCFA) to examine the IGDS9-SF measurement invariance across gamers from the United States of America (USA), India, and the United Kingdom (UK). A total of 1013 gamers from the USA (n = 405), India (n = 336), and the UK (n = 272) were recruited. Although the one-factor structure of the IGD construct was supported, cross-country variations were demonstrated considering the way that this was reflected on items assessing preoccupation/salience, tolerance, deception, gaming escapism/mood modification, as well as daily activities' impairment related to gaming. Furthermore, the same scores on items assessing withdrawal symptoms, tolerance, lack of control over gaming engagement, escapism/mood modification and daily activities impairment associated to gaming, have been found to reflect various levels of IGD severity across the three groups. The implications of these results are further discussed in the context of existing evidence regarding the assessment of IGD. Copyright © 2017 Elsevier B.V. All rights reserved.

30 CFR 77.216-2 - Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements...

Code of Federal Regulations, 2013 CFR

2013-07-01

... the District Manager. (b) Any changes or modifications to plans for water, sediment, or slurry... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements; changes or modifications; certification. 77.216-2 Section...

30 CFR 77.216-2 - Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements...

Code of Federal Regulations, 2012 CFR

2012-07-01

... the District Manager. (b) Any changes or modifications to plans for water, sediment, or slurry... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements; changes or modifications; certification. 77.216-2 Section...

30 CFR 77.216-2 - Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements...

Code of Federal Regulations, 2011 CFR

2011-07-01

... the District Manager. (b) Any changes or modifications to plans for water, sediment, or slurry... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements; changes or modifications; certification. 77.216-2 Section...

30 CFR 77.216-2 - Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements...

Code of Federal Regulations, 2014 CFR

2014-07-01

... the District Manager. (b) Any changes or modifications to plans for water, sediment, or slurry... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements; changes or modifications; certification. 77.216-2 Section...

Fitting Meta-Analytic Structural Equation Models with Complex Datasets

ERIC Educational Resources Information Center

Wilson, Sandra Jo; Polanin, Joshua R.; Lipsey, Mark W.

2016-01-01

A modification of the first stage of the standard procedure for two-stage meta-analytic structural equation modeling for use with large complex datasets is presented. This modification addresses two common problems that arise in such meta-analyses: (a) primary studies that provide multiple measures of the same construct and (b) the correlation…

Speckle contrast techniques in the study of tissue thermal modification and denaturation

NASA Astrophysics Data System (ADS)

Agafonov, Dmitry N.; Kuznetsova, Liana V.; Zimnyakov, Dmitry A.; Sviridov, Alexander P.; Omelchenko, Alexander I.

2002-05-01

Results of the contrast analysis of time-averaged dynamic speckle patterns in application to monitoring of the structure modification of the thermally treated collagenous tissue such as cartilage are presented. The modification presumably induced by the bound to free water phase transition in the matrix of the treated tissue cause the specific feature of evolution of the time-averaged speckle contrast with the change of the current temperature of modified collagen tissue. This evolution appears as hysteresis associated with irreversible changes in tissue structure.

[Genotoxic modification of nucleic acid bases and biological consequences of it. Review and prospects of experimental and computational investigations

NASA Technical Reports Server (NTRS)

Poltev, V. I.; Bruskov, V. I.; Shuliupina, N. V.; Rein, R.; Shibata, M.; Ornstein, R.; Miller, J.

1993-01-01

The review is presented of experimental and computational data on the influence of genotoxic modification of bases (deamination, alkylation, oxidation) on the structure and biological functioning of nucleic acids. Pathways are discussed for the influence of modification on coding properties of bases, on possible errors of nucleic acid biosynthesis, and on configurations of nucleotide mispairs. The atomic structure of nucleic acid fragments with modified bases and the role of base damages in mutagenesis and carcinogenesis are considered.

High-pressure polymorphism of As2S3 and new AsS2 modification with layered structure

NASA Astrophysics Data System (ADS)

Bolotina, N. B.; Brazhkin, V. V.; Dyuzheva, T. I.; Katayama, Y.; Kulikova, L. F.; Lityagina, L. V.; Nikolaev, N. A.

2014-01-01

At normal pressure, the As2S3 compound is the most stable equilibrium modification with unique layered structure. The possibility of high-pressure polymorphism of this substance remains questionable. Our research showed that the As2S3 substance was metastable under pressures P > 6 GPa decomposing into two high-pressure phases: As2S3 → AsS2 + AsS. New AsS2 phase can be conserved in the single crystalline form in metastable state at room pressure up to its melting temperature (470 K). This modification has the layered structure with P1211 monoclinic symmetry group; the unit-cell values are a = 7.916(2) Å, b = 9.937(2) Å, c = 7.118(1) Å, β = 106.41° ( Z = 8, density 3.44 g/cm3). Along with the recently studied AsS high-pressure modification, the new AsS2 phase suggests that high pressure polymorphism is a very powerful tool to create new layered-structure phases with "wrong" stoichiometry.

The computational nature of memory modification

PubMed Central

Gershman, Samuel J; Monfils, Marie-H; Norman, Kenneth A; Niv, Yael

2017-01-01

Retrieving a memory can modify its influence on subsequent behavior. We develop a computational theory of memory modification, according to which modification of a memory trace occurs through classical associative learning, but which memory trace is eligible for modification depends on a structure learning mechanism that discovers the units of association by segmenting the stream of experience into statistically distinct clusters (latent causes). New memories are formed when the structure learning mechanism infers that a new latent cause underlies current sensory observations. By the same token, old memories are modified when old and new sensory observations are inferred to have been generated by the same latent cause. We derive this framework from probabilistic principles, and present a computational implementation. Simulations demonstrate that our model can reproduce the major experimental findings from studies of memory modification in the Pavlovian conditioning literature. DOI: http://dx.doi.org/10.7554/eLife.23763.001 PMID:28294944

Modification of transparent materials with ultrashort laser pulses: What is energetically and mechanically meaningful?

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

Bulgakova, Nadezhda M., E-mail: nadezhda.bulgakova@hilase.cz; Institute of Thermophysics SB RAS, 1 Lavrentyev Ave., 630090 Novosibirsk; Zhukov, Vladimir P.

A comprehensive analysis of laser-induced modification of bulk glass by single ultrashort laser pulses is presented which is based on combination of optical Maxwell-based modeling with thermoelastoplastic simulations of post-irradiation behavior of matter. A controversial question on free electron density generated inside bulk glass by ultrashort laser pulses in modification regimes is addressed on energy balance grounds. Spatiotemporal dynamics of laser beam propagation in fused silica have been elucidated for the regimes used for direct laser writing in bulk glass. 3D thermoelastoplastic modeling of material relocation dynamics under laser-induced stresses has been performed up to the microsecond timescale when allmore » motions in the material decay. The final modification structure is found to be imprinted into material matrix already at sub-nanosecond timescale. Modeling results agree well with available experimental data on laser light transmission through the sample and the final modification structure.« less

Investigation of metrics to assess vascular flow modifications for diverter device designs using hydrodynamics and angiographic studies

NASA Astrophysics Data System (ADS)

Ionita, Ciprian N.; Bednarek, Daniel R.; Rudin, Stephen

2012-03-01

Intracranial aneurysm treatment with flow diverters (FD) is a new minimally invasive approach, recently approved for use in human patients. Attempts to correlate the flow reduction observed in angiograms with a parameter related to the FD structure have not been totally successful. To find the proper parameter, we investigated four porous-media flow models. The models describing the relation between the pressure drop and flow velocity that are investigated include the capillary theory linear model (CTLM), the drag force linear model (DFLM), the simple quadratic model (SQM) and the modified quadratic model (MQM). Proportionality parameters are referred to as permeability for the linear models and resistance for the quadratic ones. A two stage experiment was performed. First, we verified flow model validity by placing six different stainless-steel meshes, resembling FD structures, in known flow conditions. The best flow model was used for the second stage, where six different FD's were inserted in aneurysm phantoms and flow modification was estimated using angiographically derived time density curves (TDC). Finally, TDC peak variation was compared with the FD parameter. Model validity experiments indicated errors of: 70% for the linear models, 26% for the SQM and 7% for the MQM. The resistance calculated according to the MQM model correlated well with the contrast flow reduction. Results indicate that resistance calculated according to MQM is appropriate to characterize the FD and could explain the flow modification observed in angiograms.

Synthesis and Crystal Structure of 2’-Se-modified guanosine Containing DNA

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

Salon, J.; Sheng, J; Gan, J

Selenium modification of nucleic acids is of great importance in X-ray crystal structure determination and functional study of nucleic acids. Herein, we describe a convenient synthesis of a new building block, the 2{prime}-SeMe-modified guanosine (G{sub Se}) phosphoramidite, and report the first incorporation of the 2{prime}-Se-G moiety into DNA. The X-ray crystal structure of the 2{prime}-Se-modified octamer DNA (5{prime}-GTG{sub Se}TACAC-3{prime}) was determined at a resolution of 1.20 {angstrom}. We also found that the 2{prime}-Se modification points to the minor groove and that the modified and native structures are virtually identical. Furthermore, we observed that the 2{prime}-Se-G modification can significantly facilitate themore » crystal growth with respect to the corresponding native DNA.« less

Impact of home modification services on ability in everyday life for people ageing with disabilities.

PubMed

Petersson, Ingela; Lilja, Margareta; Hammel, Joy; Kottorp, Anders

2008-04-01

To examine the impact of home modifications on self-rated ability in everyday life from various aspects for people ageing with disabilities. The study sample was recruited from an agency providing home modification services in Sweden and comprised 73 subjects whose referrals had been approved and who were scheduled to receive home modifications (intervention group) and 41 subjects waiting for their applications to be assessed for approval (comparison group). The subjects rated their ability in everyday life using the Client-Clinician Assessment Protocol Part I on 2 occasions: at baseline and follow-up. The Client-Clinician Assessment Protocol Part I provides data on the clients' self-rated independence, difficulty and safety in everyday life. The data were first subjected to Rasch analysis in order to convert the raw scores into interval measures. Further analyses to investigate changes in self-rated ability were conducted with parametric statistics. Subjects who had received home modifications reported a statistically significant improvement in their self-rated ability in everyday life compared with those in the comparison group. Subjects who had received home modifications reported less difficulty and increased safety, especially in tasks related to self-care in the bathroom and transfers, such as getting in and out of the home. Home modifications have a positive impact on self-rated ability in everyday life, especially on decreasing the level of difficulty and increasing safety.

tRNA modification profiles of the fast-proliferating cancer cells

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

Dong, Chao; Niu, Leilei; Song, Wei

Despite the recent progress in RNA modification study, a comprehensive modification profile is still lacking for mammalian cells. Using a quantitative HPLC/MS/MS assay, we present here a study where RNA modifications are examined in term of the major RNA species. With paired slow- and fast-proliferating cell lines, distinct RNA modification profiles are first revealed for diverse RNA species. Compared to mRNAs, increased ribose and nucleobase modifications are shown for the highly-structured tRNAs and rRNAs, lending support to their contribution to the formation of high-order structures. This study also reveals a dynamic tRNA modification profile in the fast-proliferating cells. In additionmore » to cultured cells, this unique tRNA profile has been further confirmed with endometrial cancers and their adjacent normal tissues. Taken together, the results indicate that tRNA is a actively regulated RNA species in the fast-proliferating cancer cells, and suggest that they may play a more active role in biological process than expected. -- Highlights: •RNA modifications were first examined in term of the major RNA species. •A dynamic tRNA modifications was characterized for the fast-proliferating cells. •The unique tRNA profile was confirmed with endometrial cancers and their adjacent normal tissues. •tRNA was predicted as an actively regulated RNA species in the fast-proliferating cancer cells.« less

Analytical and functional similarity of Amgen biosimilar ABP 215 to bevacizumab

PubMed Central

Seo, Neungseon; Polozova, Alla; Zhang, Mingxuan; Yates, Zachary; Cao, Shawn; Li, Huimin; Kuhns, Scott; Maher, Gwendolyn; McBride, Helen J.; Liu, Jennifer

2018-01-01

ABSTRACT ABP 215 is a biosimilar product to bevacizumab. Bevacizumab acts by binding to vascular endothelial growth factor A, inhibiting endothelial cell proliferation and new blood vessel formation, thereby leading to tumor vasculature normalization. The ABP 215 analytical similarity assessment was designed to assess the structural and functional similarity of ABP 215 and bevacizumab sourced from both the United States (US) and the European Union (EU). Similarity assessment was also made between the US- and EU-sourced bevacizumab to assess the similarity between the two products. The physicochemical properties and structural similarity of ABP 215 and bevacizumab were characterized using sensitive state-of-the-art analytical techniques capable of detecting small differences in product attributes. ABP 215 has the same amino acid sequence and exhibits similar post-translational modification profiles compared to bevacizumab. The functional similarity assessment employed orthogonal assays designed to interrogate all expected biological activities, including those known to affect the mechanisms of action for ABP 215 and bevacizumab. More than 20 batches of bevacizumab (US) and bevacizumab (EU), and 13 batches of ABP 215 representing unique drug substance lots were assessed for similarity. The large dataset allows meaningful comparisons and garners confidence in the overall conclusion for the analytical similarity assessment of ABP 215 to both US- and EU-sourced bevacizumab. The structural and purity attributes, and biological properties of ABP 215 are demonstrated to be highly similar to those of bevacizumab. PMID:29553864

Exploring Covalent Allosteric Inhibition of Antigen 85C from Mycobacterium tuberculosis by Ebselen Derivatives

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

Goins, Christopher M.; Dajnowicz, Steven; Thanna, Sandeep

Previous studies identified ebselen as a potent in vitro and in vivo inhibitor of the Mycobacterium tuberculosis ( Mtb) antigen 85 (Ag85) complex, comprising three homologous enzymes required for the biosynthesis of the mycobacterial cell wall. In this study, the Mtb Ag85C enzyme was cocrystallized with azido and adamantyl ebselen derivatives, resulting in two crystallographic structures of 2.01 and 1.30 Å resolution, respectively. Both structures displayed the anticipated covalent modification of the solvent accessible, noncatalytic Cys209 residue forming a selenenylsulfide bond. Continuous difference density for both thiol modifiers allowed for the assessment of interactions that influence ebselen binding and inhibitormore » orientation that were unobserved in previous Ag85C ebselen structures. The k inact/ K I values for ebselen, adamantyl ebselen, and azido ebselen support the importance of observed constructive chemical interactions with Arg239 for increased in vitro efficacy toward Ag85C. To better understand the in vitro kinetic properties of these ebselen derivatives, the energetics of specific protein–inhibitor interactions and relative reaction free energies were calculated for ebselen and both derivatives using density functional theory. These studies further support the different in vitro properties of ebselen and two select ebselen derivatives from our previously published ebselen library with respect to kinetics and protein–inhibitor interactions. In both structures, the α9 helix was displaced farther from the enzyme active site than the previous Ag85C ebselen structure, resulting in the restructuring of a connecting loop and imparting a conformational change to residues believed to play a role in substrate binding specific to Ag85C. These notable structural changes directly affect protein stability, reducing the overall melting temperature by up to 14.5 °C, resulting in the unfolding of protein at physiological temperatures. Additionally, this structural rearrangement due to covalent allosteric modification creates a sizable solvent network that encompasses the active site and extends to the modified Cys209 residue. In all, this study outlines factors that influence enzyme inhibition by ebselen and its derivatives while further highlighting the effects of the covalent modification of Cys209 by said inhibitors on the structure and stability of Ag85C. Moreover, the results suggest a strategy for developing new classes of Ag85 inhibitors with increased specificity and potency.« less

Exploring Covalent Allosteric Inhibition of Antigen 85C from Mycobacterium tuberculosis by Ebselen Derivatives.

PubMed

Goins, Christopher M; Dajnowicz, Steven; Thanna, Sandeep; Sucheck, Steven J; Parks, Jerry M; Ronning, Donald R

2017-05-12

Previous studies identified ebselen as a potent in vitro and in vivo inhibitor of the Mycobacterium tuberculosis (Mtb) antigen 85 (Ag85) complex, comprising three homologous enzymes required for the biosynthesis of the mycobacterial cell wall. In this study, the Mtb Ag85C enzyme was cocrystallized with azido and adamantyl ebselen derivatives, resulting in two crystallographic structures of 2.01 and 1.30 Å resolution, respectively. Both structures displayed the anticipated covalent modification of the solvent accessible, noncatalytic Cys209 residue forming a selenenylsulfide bond. Continuous difference density for both thiol modifiers allowed for the assessment of interactions that influence ebselen binding and inhibitor orientation that were unobserved in previous Ag85C ebselen structures. The k inact /K I values for ebselen, adamantyl ebselen, and azido ebselen support the importance of observed constructive chemical interactions with Arg239 for increased in vitro efficacy toward Ag85C. To better understand the in vitro kinetic properties of these ebselen derivatives, the energetics of specific protein-inhibitor interactions and relative reaction free energies were calculated for ebselen and both derivatives using density functional theory. These studies further support the different in vitro properties of ebselen and two select ebselen derivatives from our previously published ebselen library with respect to kinetics and protein-inhibitor interactions. In both structures, the α9 helix was displaced farther from the enzyme active site than the previous Ag85C ebselen structure, resulting in the restructuring of a connecting loop and imparting a conformational change to residues believed to play a role in substrate binding specific to Ag85C. These notable structural changes directly affect protein stability, reducing the overall melting temperature by up to 14.5 °C, resulting in the unfolding of protein at physiological temperatures. Additionally, this structural rearrangement due to covalent allosteric modification creates a sizable solvent network that encompasses the active site and extends to the modified Cys209 residue. In all, this study outlines factors that influence enzyme inhibition by ebselen and its derivatives while further highlighting the effects of the covalent modification of Cys209 by said inhibitors on the structure and stability of Ag85C. Furthermore, the results suggest a strategy for developing new classes of Ag85 inhibitors with increased specificity and potency.

Exploring Covalent Allosteric Inhibition of Antigen 85C from Mycobacterium tuberculosis by Ebselen Derivatives

DOE PAGES

Goins, Christopher M.; Dajnowicz, Steven; Thanna, Sandeep; ...

2017-03-13

Previous studies identified ebselen as a potent in vitro and in vivo inhibitor of the Mycobacterium tuberculosis ( Mtb) antigen 85 (Ag85) complex, comprising three homologous enzymes required for the biosynthesis of the mycobacterial cell wall. In this study, the Mtb Ag85C enzyme was cocrystallized with azido and adamantyl ebselen derivatives, resulting in two crystallographic structures of 2.01 and 1.30 Å resolution, respectively. Both structures displayed the anticipated covalent modification of the solvent accessible, noncatalytic Cys209 residue forming a selenenylsulfide bond. Continuous difference density for both thiol modifiers allowed for the assessment of interactions that influence ebselen binding and inhibitormore » orientation that were unobserved in previous Ag85C ebselen structures. The k inact/ K I values for ebselen, adamantyl ebselen, and azido ebselen support the importance of observed constructive chemical interactions with Arg239 for increased in vitro efficacy toward Ag85C. To better understand the in vitro kinetic properties of these ebselen derivatives, the energetics of specific protein–inhibitor interactions and relative reaction free energies were calculated for ebselen and both derivatives using density functional theory. These studies further support the different in vitro properties of ebselen and two select ebselen derivatives from our previously published ebselen library with respect to kinetics and protein–inhibitor interactions. In both structures, the α9 helix was displaced farther from the enzyme active site than the previous Ag85C ebselen structure, resulting in the restructuring of a connecting loop and imparting a conformational change to residues believed to play a role in substrate binding specific to Ag85C. These notable structural changes directly affect protein stability, reducing the overall melting temperature by up to 14.5 °C, resulting in the unfolding of protein at physiological temperatures. Additionally, this structural rearrangement due to covalent allosteric modification creates a sizable solvent network that encompasses the active site and extends to the modified Cys209 residue. In all, this study outlines factors that influence enzyme inhibition by ebselen and its derivatives while further highlighting the effects of the covalent modification of Cys209 by said inhibitors on the structure and stability of Ag85C. Moreover, the results suggest a strategy for developing new classes of Ag85 inhibitors with increased specificity and potency.« less

Gradual adaptation of bone structure to aquatic lifestyle in extinct sloths from Peru

PubMed Central

Amson, Eli; de Muizon, Christian; Laurin, Michel; Argot, Christine; de Buffrénil, Vivian

2014-01-01

Non-pathological densification (osteosclerosis) and swelling (pachyostosis) of bones are the main modifications affecting the skeleton of land vertebrates (tetrapods) that returned to water. However, a precise temporal calibration of the acquisition of such adaptations is still wanting. Here, we assess the timing of such acquisition using the aquatic sloth Thalassocnus, from the Neogene of the Pisco Formation, Peru. This genus is represented by five species occurring in successive vertebrate-bearing horizons of distinct ages. It yields the most detailed data about the gradual acquisition of aquatic adaptations among tetrapods, in displaying increasing osteosclerosis and pachyostosis through time. Such modifications, reflecting a shift in the habitat from terrestrial to aquatic, occurred over a short geological time span (ca 4 Myr). Otherwise, the bones of terrestrial pilosans (sloths and anteaters) are much more compact than the mean mammalian condition, which suggests that the osteosclerosis of Thalassocnus may represent an exaptation. PMID:24621950

Click chemistry modification of natural keratin fibers for sustained shrink-resist performance.

PubMed

Yu, Dan; Cai, Jackie Y; Church, Jeffrey S; Wang, Lijing

2015-01-01

This paper introduces a novel chemical treatment for achieving sustained shrink-resist performance on natural keratin fibers. The new treatment involves the controlled reduction of keratin in the cuticle region of the fiber, and the application of a water soluble diacrylate, namely glycerol 1,3-diglycerolate diacrylate (GDA), on the reduced keratin substrate. The acrylate groups of the GDA react with cysteine residues in the reduced keratin through thiol-ene click reactions at room temperature, leading to GDA grafting and the formation of GDA crosslinks in the keratin structure. The modified substrates were characterized by infrared spectroscopy and scanning electron microscopy, and assessed for its shrink-resistance and wet burst strength. This chemical modification has shown to alter the fiber surface morphology and hydrophilicity, resulting in substantially improved shrink-resistance with good fiber strength retention. Possible shrink-resistance mechanisms were also discussed. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

m1A Post-Transcriptional Modification in tRNAs.

PubMed

Oerum, Stephanie; Dégut, Clément; Barraud, Pierre; Tisné, Carine

2017-02-21

To date, about 90 post-transcriptional modifications have been reported in tRNA expanding their chemical and functional diversity. Methylation is the most frequent post-transcriptional tRNA modification that can occur on almost all nitrogen sites of the nucleobases, on the C5 atom of pyrimidines, on the C2 and C8 atoms of adenosine and, additionally, on the oxygen of the ribose 2'-OH. The methylation on the N1 atom of adenosine to form 1-methyladenosine (m1A) has been identified at nucleotide position 9, 14, 22, 57, and 58 in different tRNAs. In some cases, these modifications have been shown to increase tRNA structural stability and induce correct tRNA folding. This review provides an overview of the currently known m1A modifications, the different m1A modification sites, the biological role of each modification, and the enzyme responsible for each methylation in different species. The review further describes, in detail, two enzyme families responsible for formation of m1A at nucleotide position 9 and 58 in tRNA with a focus on the tRNA binding, m1A mechanism, protein domain organisation and overall structures.

Structural and physico-chemical properties of insoluble rice bran fiber: effect of acid–base induced modifications

USDA-ARS?s Scientific Manuscript database

The structural modifications of insoluble rice bran fiber (IRBF) by sequential regimes of sulphuric acid (H2SO4) and their effects on the physicochemical attributes were studied. The increment of H2SO4 concentration resulted in decreased water holding capacity that ultimately enhanced the oil bindin...

Structural basis of ubiquitin modification by the Legionella effector SdeA.

PubMed

Dong, Yanan; Mu, Yajuan; Xie, Yongchao; Zhang, Yupeng; Han, Youyou; Zhou, Yu; Wang, Wenhe; Liu, Zihe; Wu, Mei; Wang, Hao; Pan, Man; Xu, Ning; Xu, Cong-Qiao; Yang, Maojun; Fan, Shilong; Deng, Haiteng; Tan, Tianwei; Liu, Xiaoyun; Liu, Lei; Li, Jun; Wang, Jiawei; Fang, Xianyang; Feng, Yue

2018-05-01

Protein ubiquitination is a multifaceted post-translational modification that controls almost every process in eukaryotic cells. Recently, the Legionella effector SdeA was reported to mediate a unique phosphoribosyl-linked ubiquitination through successive modifications of the Arg42 of ubiquitin (Ub) by its mono-ADP-ribosyltransferase (mART) and phosphodiesterase (PDE) domains. However, the mechanisms of SdeA-mediated Ub modification and phosphoribosyl-linked ubiquitination remain unknown. Here we report the structures of SdeA in its ligand-free, Ub-bound and Ub-NADH-bound states. The structures reveal that the mART and PDE domains of SdeA form a catalytic domain over its C-terminal region. Upon Ub binding, the canonical ADP-ribosyltransferase toxin turn-turn (ARTT) and phosphate-nicotinamide (PN) loops in the mART domain of SdeA undergo marked conformational changes. The Ub Arg72 might act as a 'probe' that interacts with the mART domain first, and then movements may occur in the side chains of Arg72 and Arg42 during the ADP-ribosylation of Ub. Our study reveals the mechanism of SdeA-mediated Ub modification and provides a framework for further investigations into the phosphoribosyl-linked ubiquitination process.

Apparatus and method for electrochemical modification of liquids

DOEpatents

James, Patrick I

2015-04-21

An apparatus for electrochemical modification of liquid streams employing an electrolytic cell which includes an anode compartment defined by an anode structure where oxidation is effected, containing a liquid electrolyte anolyte, and a cathode compartment defined by a cathode structure where reduction is effected containing a liquid electrolyte catholyte. In addition, the electrolytic cell includes at least one additional compartment arranged at least partially between the anode compartment and the cathode compartment and separated from the anode compartment and the cathode compartment by a separator structure arranged to supports ionic conduction of current between the anode structure and the cathode structure.

Molecular modification of native coffee polysaccharide using subcritical water treatment: Structural characterization, antioxidant, and DNA protecting activities.

PubMed

Getachew, Adane Tilahun; Chun, Byung Soo

2017-06-01

Polysaccharides are an abundant resource in coffee beans and have proved to show numerous bioactivities. Despite their abundance, their activities are not always satisfactory mostly due to their structure and large molecular size. Molecular modifications of native polysaccharides can overcome this problem. In this study, we used a novel and green method to modify native coffee polysaccharides using subcritical water (SCW) treatment. The SCW treatment was used at the temperature of 180°C-220°C and pressure of 30-60bar. The molecular and structural modification of the polysaccharides was confirmed using several techniques such as FT-IR, UV spectroscopy, XRD, and TGA. The antioxidant activity of the modified polysaccharides was evaluated using several chemical and Saccharomyces cerevisiae-based high throughput assays. The modified polysaccharides showed high antioxidant activities in all tested assays. Moreover, the polysaccharides showed high DNA protection activities. Therefore, SCW could be employed as a green solvent for molecular modification of polysaccharides. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of SEPS solar array technology for orbital service module application

NASA Technical Reports Server (NTRS)

1978-01-01

Work performed in the following assessment areas on the SEPS solar array is reported: (1) requirements definition, (2) electrical design evaluation, (3) mechanical design evaluation, and (4) design modification analysis. General overall assessment conclusions are summarized. There are no known serious design limitations involved in the implementation of the recommended design modifications. A section of orbiter and array engineering drawings is included.

Modifications to the accuracy assessment analysis routine MLTCRP to produce an output file

NASA Technical Reports Server (NTRS)

Carnes, J. G.

1978-01-01

Modifications are described that were made to the analysis program MLTCRP in the accuracy assessment software system to produce a disk output file. The output files produced by this modified program are used to aggregate data for regions greater than a single segment.

Development of a core outcome set for disease modification trials in mild to moderate dementia: a systematic review, patient and public consultation and consensus recommendations.

PubMed Central

Webster, Lucy; Groskreutz, Derek; Grinbergs-Saull, Anna; Howard, Rob; O'Brien, John T; Mountain, Gail; Banerjee, Sube; Woods, Bob; Perneczky, Robert; Lafortune, Louise; Roberts, Charlotte; McCleery, Jenny; Pickett, James; Bunn, Frances; Challis, David; Charlesworth, Georgina; Featherstone, Katie; Fox, Chris; Goodman, Claire; Jones, Roy; Lamb, Sallie; Moniz-Cook, Esme; Schneider, Justine; Shepperd, Sasha; Surr, Claire; Thompson-Coon, Jo; Ballard, Clive; Brayne, Carol; Burke, Orlaith; Burns, Alistair; Clare, Linda; Garrard, Peter; Kehoe, Patrick; Passmore, Peter; Holmes, Clive; Maidment, Ian; Murtagh, Fliss; Robinson, Louise; Livingston, Gill

2017-01-01

BACKGROUND There is currently no disease-modifying treatment available to halt or delay the progression of the disease pathology in dementia. An agreed core set of the best-available and most appropriate outcomes for disease modification would facilitate the design of trials and ensure consistency across disease modification trials, as well as making results comparable and meta-analysable in future trials. OBJECTIVES To agree a set of core outcomes for disease modification trials for mild to moderate dementia with the UK dementia research community and patient and public involvement (PPI). DATA SOURCES We included disease modification trials with quantitative outcomes of efficacy from (1) references from related systematic reviews in workstream 1; (2) searches of the Cochrane Dementia and Cognitive Improvement Group study register, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, EMBASE, Latin American and Caribbean Health Sciences Literature and PsycINFO on 11 December 2015, and clinical trial registries [International Standard Randomised Controlled Trial Number (ISRCTN) and clinicaltrials.gov] on 22 and 29 January 2016; and (3) hand-searches of reference lists of relevant systematic reviews from database searches. REVIEW METHODS The project consisted of four workstreams. (1) We obtained related core outcome sets and work from co-applicants. (2) We systematically reviewed published and ongoing disease modification trials to identify the outcomes used in different domains. We extracted outcomes used in each trial, recording how many used each outcome and with how many participants. We divided outcomes into the domains measured and searched for validation data. (3) We consulted with PPI participants about recommended outcomes. (4) We presented all the synthesised information at a conference attended by the wider body of National Institute for Health Research (NIHR) dementia researchers to reach consensus on a core set of outcomes. RESULTS We included 149 papers from the 22,918 papers screened, referring to 125 individual trials. Eighty-one outcomes were used across trials, including 72 scales [31 cognitive, 12 activities of daily living (ADLs), 10 global, 16 neuropsychiatric and three quality of life] and nine biological techniques. We consulted with 18 people for PPI. The conference decided that only cognition and biological markers are core measures of disease modification. Cognition should be measured by the Mini Mental State Examination (MMSE) or the Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog), and brain changes through structural magnetic resonance imaging (MRI) in a subset of participants. All other domains are important but not core. We recommend using the Neuropsychiatric Inventory for neuropsychiatric symptoms: the Disability Assessment for Dementia for ADLs, the Dementia Quality of Life Measure for quality of life and the Clinical Dementia Rating scale to measure dementia globally. LIMITATIONS Most of the trials included participants with Alzheimer's disease, so recommendations may not apply to other types of dementia. We did not conduct economic analyses. The PPI consultation was limited to members of the Alzheimer's Society Research Network. CONCLUSIONS Cognitive outcomes and biological markers form the core outcome set for future disease modification trials, measured by the MMSE or ADAS-Cog, and structural MRI in a subset of participants. FUTURE WORK We envisage that the core set may be superseded in the future, particularly for other types of dementia. There is a need to develop an algorithm to compare scores on the MMSE and ADAS-Cog. STUDY REGISTRATION The project was registered with Core Outcome Measures in Effectiveness Trials [ www.comet-initiative.org/studies/details/819?result=true (accessed 7 April 2016)]. The systematic review protocol is registered as PROSPERO CRD42015027346. FUNDING The National Institute for Health Research Health Technology Assessment programme. PMID:28625273

Rutile TiO2 Flocculent Ripples with High Antireflectivity and Superhydrophobicity on the Surface of Titanium under 10 ns Laser Irradiation without Focusing.

PubMed

Pan, Aifei; Wang, Wenjun; Mei, Xuesong; Wang, Kedian; Yang, Xianbin

2017-09-26

We report on the formation of rutile TiO 2 flocculent laser-induced periodic surface structures (LIPSSs) with high antireflectivity and superhydrophobicity on the surface of titanium under 10 ns 1064 nm laser irradiation without focusing. The center part of the Gaussian laser beam is used to deposit flocculent structure and the edge part used to produce LIPSSs. The melt and modification thresholds of titanium were determined first, and then, the melt and modification spot-overlap numbers, several responsible for the formation of flocculent structure and LIPSSs, were introduced. It is found that both the melt and modification spot-overlap numbers increase with an increase in laser fluence and spot-overlap number, contributing to the production of flocculent LIPSSs. LIPSSs are obtained with the modification spot-overlap number above 300, and the amount of flocculent structures increases with an increase in the peak laser fluence and spot-overlap number. Then, considering that the fine adjustment of the melt and modification spot-overlop numbers in one-time line scanning is quite difficult, the composite structure, of which both LIPSSs and flocculent structures are distinct, was optimized using laser line scanning twice. On this basis, a characterization test shows the sample full of the flocculent LIPSSs represents best antireflectivity with the value around 10% in the waveband between 260 and 2600 nm (advance 5 times in infrared wavelengths compared to the initial titanium surface), and shows the no-stick hydrophobicity with the contact angle of 160° and roll-off angle of 25° because of the pure rutile phase of TiO 2 .

Mass spectrometry-based carboxyl footprinting of proteins: Method evaluation

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

Zhang, Hao; Wen, Jianzhong; Huang, Richard Y-C.

2012-02-01

Protein structure determines function in biology, and a variety of approaches have been employed to obtain structural information about proteins. Mass spectrometry-based protein footprinting is one fast-growing approach. One labeling-based footprinting approach is the use of a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and glycine ethyl ester (GEE) to modify solvent-accessible carboxyl groups on glutamate (E) and aspartate (D). This paper describes method development of carboxyl-group modification in protein footprinting. The modification protocol was evaluated by using the protein calmodulin as a model. Because carboxyl-group modification is a slow reaction relative to protein folding and unfolding, there is an issue that modificationsmore » at certain sites may induce protein unfolding and lead to additional modification at sites that are not solvent-accessible in the wild-type protein. We investigated this possibility by using hydrogen deuterium amide exchange (H/DX). The study demonstrated that application of carboxyl group modification in probing conformational changes in calmodulin induced by Ca{sup 2+} binding provides useful information that is not compromised by modification-induced protein unfolding.« less

Influence of 5-N-carboxamide modifications on the thermodynamic stability of oligonucleotides

PubMed Central

Wolk, Steven K.; Shoemaker, Richard K.; Mayfield, Wes S.; Mestdagh, Andrew L.; Janjic, Nebojsa

2015-01-01

We have recently shown that the incorporation of modified nucleotides such as 5-N-carboxamide-deoxyuridines into random nucleic acid libraries improves success rates in SELEX experiments and facilitates the identification of ligands with slow off-rates. Here we report the impact of these modifications on the thermodynamic stability of both duplexes and intramolecular ‘single-stranded’ structures. Within duplexes, large, hydrophobic naphthyl groups were destabilizing relative to the all natural DNA duplex, while the hydrophilic groups exhibited somewhat improved duplex stability. All of the significant changes in stability were driven by opposing contributions from the enthalpic and entropic terms. In contrast, both benzyl and naphthyl modifications stabilized intramolecular single-stranded structures relative to their natural DNA analogs, consistent with the notion that intramolecular folding allows formation of novel, stabilizing hydrophobic interactions. Imino proton NMR data provided evidence that elements of the folded structure form at temperatures well below the Tm, with a melting transition that is distinctly less cooperative when compared to duplex DNA. Although there are no data to suggest that the unmodified DNA sequences fold into structures similar to their modified analogs, this still represents clear evidence that these modifications impart thermodynamic stability to the folded structure not achievable with unmodified DNA. PMID:26438535

Enzymatic synthesis of structured lipids.

PubMed

Iwasaki, Yugo; Yamane, Tsuneo

2004-01-01

Structured lipids (SLs) are defined as lipids that are modified chemically or enzymatically in order to change their structure. This review deals with structured triacylglycerols (STGs) and structured phospholipids (SPLs). The most typical STGs are MLM-type STGs, having medium chain fatty acids (FAs) at the 1- and 3-positions and a long chain fatty acid at the 2- position. MLM-type STGs are synthesized by: 1) 1,3-position-specific lipase-catalyzed acyl exchange of TG with FA or with FA ethylester (FAEt); 2) 1,3-position-specific lipase-catalyzed acylation of glycerol with FA, giving symmetric 1,3-diacyl-sn-glycerol, followed by chemical acylation at the sn-2 position, and; 3) 1,3-position-specific lipase-catalyzed deacylation of TG, giving 2-monoacylglycerol, followed by reacylation at the 1- and 3-positions with FA or with (FAEt). Enzymatic preparation of SPLs requires: 1) acyl group modification, and 2) head group modification of phospholipids. Acyl group modification is performed using lipases or phospholipase A2-mediated transesterification or ester synthesis to introduce arbitrary fatty acid to phospholipids. Head group modification is carried out by phospholipase D-catalyzed transphosphatidylation. A wide range of compounds can be introduced into the polar head of phospholipids, making it possible to prepare various SPLs.

Synthesis of (-)-pseudotabersonine, (-)-pseudovincadifformine, and (+)-coronaridine enabled by photoredox catalysis in flow.

PubMed

Beatty, Joel W; Stephenson, Corey R J

2014-07-23

Natural product modification with photoredox catalysis allows for mild, chemoselective access to a wide array of related structures in complex areas of chemical space, providing the possibility for novel structural motifs as well as useful quantities of less abundant congeners. While amine additives have been used extensively as stoichiometric electron donors for photocatalysis, the controlled modification of amine substrates through single-electron oxidation is ideal for the synthesis and modification of alkaloids. Here, we report the conversion of the amine (+)-catharanthine into the natural products (-)-pseudotabersonine, (-)-pseudovincadifformine, and (+)-coronaridine utilizing visible light photoredox catalysis.

Understanding the structural and dynamic consequences of DNA epigenetic modifications: Computational insights into cytosine methylation and hydroxymethylation

PubMed Central

Carvalho, Alexandra T P; Gouveia, Leonor; Kanna, Charan Raju; Wärmländer, Sebastian K T S; Platts, Jamie A; Kamerlin, Shina Caroline Lynn

2014-01-01

We report a series of molecular dynamics (MD) simulations of up to a microsecond combined simulation time designed to probe epigenetically modified DNA sequences. More specifically, by monitoring the effects of methylation and hydroxymethylation of cytosine in different DNA sequences, we show, for the first time, that DNA epigenetic modifications change the molecule's dynamical landscape, increasing the propensity of DNA toward different values of twist and/or roll/tilt angles (in relation to the unmodified DNA) at the modification sites. Moreover, both the extent and position of different modifications have significant effects on the amount of structural variation observed. We propose that these conformational differences, which are dependent on the sequence environment, can provide specificity for protein binding. PMID:25625845

Plant Sterols: Chemical and Enzymatic Structural Modifications and Effects on Their Cholesterol-Lowering Activity.

PubMed

He, Wen-Sen; Zhu, Hanyue; Chen, Zhen-Yu

2018-03-28

Plant sterols have attracted increasing attention due to their excellent cholesterol-lowering activity. However, free plant sterols have some characteristics of low oil solubility, water insolubility, high melting point, and low bioavailability, which greatly limit their application in foods. Numerous studies have been undertaken to modify their chemical structures to improve their chemical and physical properties in meeting the needs of various applications. The present review is to summarize the literature and update the progress on structural modifications of plant sterols in the following aspects: (i) synthesis of plant sterol esters by esterification and transesterification with hydrophobic fatty acids and triacylglycerols to improve their oil solubility, (ii) synthesis of plant sterol derivatives by coupling with various hydrophilic moieties to enhance their water solubility, and (iii) mechanisms by which plant sterols reduce plasma cholesterol and the effect of structural modifications on plasma cholesterol-lowering activity of plant sterols.

Assessment of protein modifications in liver of rats under chronic treatment with paracetamol (acetaminophen) using two complementary mass spectrometry-based metabolomic approaches.

PubMed

Mast, Carole; Lyan, Bernard; Joly, Charlotte; Centeno, Delphine; Giacomoni, Franck; Martin, Jean-François; Mosoni, Laurent; Dardevet, Dominique; Pujos-Guillot, Estelle; Papet, Isabelle

2015-04-29

Liver protein can be altered under paracetamol (APAP) treatment. APAP-protein adducts and other protein modifications (oxidation/nitration, expression) play a role in hepatotoxicity induced by acute overdoses, but it is unknown whether liver protein modifications occur during long-term treatment with non-toxic doses of APAP. We quantified APAP-protein adducts and assessed other protein modifications in the liver from rats under chronic (17 days) treatment with two APAP doses (0.5% or 1% of APAP in the diet w/w). A targeted metabolomic method was validated and used to quantify APAP-protein adducts as APAP-cysteine adducts following proteolytic hydrolysis. The limit of detection was found to be 7ng APAP-cysteine/mL hydrolysate i.e. an APAP-Cys to tyrosine ratio of 0.016‰. Other protein modifications were assessed on the same protein hydrolysate by untargeted metabolomics including a new strategy to process the data and identify discriminant molecules. These two complementary mass spectrometry (MS)-based metabolic approaches enabled the assessment of a wide range of protein modifications induced by chronic treatment with APAP. APAP-protein adducts were detected even in the absence of glutathione depletion and hepatotoxicity, i.e. in the 0.5% APAP group, and increased by 218% in the 1% APAP group compared to the 0.5% APAP group. At the same time, the untargeted metabolomic method revealed a decrease in the binding of cysteine, cysteinyl-glycine and GSH to thiol groups of protein cysteine residues, an increase in the oxidation of tryptophan and proline residues and a modification in protein expression. This wide range of modifications in liver proteins occurred in rats under chronic treatment with APAP that did not induce hepatotoxicity. Copyright © 2015 Elsevier B.V. All rights reserved.

Chromatin immunoprecipitation of mouse embryos.

PubMed

Voss, Anne K; Dixon, Mathew P; McLennan, Tamara; Kueh, Andrew J; Thomas, Tim

2012-01-01

During prenatal development, a large number of different cell types are formed, the vast majority of which contain identical genetic material. The basis of the great variety in cell phenotype and function is the differential expression of the approximately 25,000 genes in the mammalian genome. Transcriptional activity is regulated at many levels by proteins, including members of the basal transcriptional apparatus, DNA-binding transcription factors, and chromatin-binding proteins. Importantly, chromatin structure dictates the availability of a specific genomic locus for transcriptional activation as well as the efficiency, with which transcription can occur. Chromatin immunoprecipitation (ChIP) is a method to assess if chromatin modifications or proteins are present at a specific locus. ChIP involves the cross linking of DNA and associated proteins and immunoprecipitation using specific antibodies to DNA-associated proteins followed by examination of the co-precipitated DNA sequences or proteins. In the last few years, ChIP has become an essential technique for scientists studying transcriptional regulation and chromatin structure. Using ChIP on mouse embryos, we can document the presence or absence of specific proteins and chromatin modifications at genomic loci in vivo during mammalian development. Here, we describe a ChIP technique adapted for mouse embryos.

Divergent actions of the pyrethroid insecticides S-bioallethrin, tefluthrin, and deltamethrin on rat Na{sub v}1.6 sodium channels

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

Tan Jianguo; Soderlund, David M., E-mail: dms6@cornell.ed

2010-09-15

We expressed rat Na{sub v}1.6 sodium channels in combination with the rat {beta}{sub 1} and {beta}{sub 2} auxiliary subunits in Xenopus laevis oocytes and evaluated the effects of the pyrethroid insecticides S-bioallethrin, deltamethrin, and tefluthrin on expressed sodium currents using the two-electrode voltage clamp technique. S-Bioallethrin, a type I structure, produced transient modification evident in the induction of rapidly decaying sodium tail currents, weak resting modification (5.7% modification at 100 {mu}M), and no further enhancement of modification upon repetitive activation by high-frequency trains of depolarizing pulses. By contrast deltamethrin, a type II structure, produced sodium tail currents that were {approx}more » 9-fold more persistent than those caused by S-bioallethrin, barely detectable resting modification (2.5% modification at 100 {mu}M), and 3.7-fold enhancement of modification upon repetitive activation. Tefluthrin, a type I structure with high mammalian toxicity, exhibited properties intermediate between S-bioallethrin and deltamethrin: intermediate tail current decay kinetics, much greater resting modification (14.1% at 100 {mu}M), and 2.8-fold enhancement of resting modification upon repetitive activation. Comparison of concentration-effect data showed that repetitive depolarization increased the potency of tefluthrin {approx} 15-fold and that tefluthrin was {approx} 10-fold more potent than deltamethrin as a use-dependent modifier of Na{sub v}1.6 sodium channels. Concentration-effect data from parallel experiments with the rat Na{sub v}1.2 sodium channel coexpressed with the rat {beta}{sub 1} and {beta}{sub 2} subunits in oocytes showed that the Na{sub v}1.6 isoform was at least 15-fold more sensitive to tefluthrin and deltamethrin than the Na{sub v}1.2 isoform. These results implicate sodium channels containing the Na{sub v}1.6 isoform as potential targets for the central neurotoxic effects of pyrethroids.« less

Identification and characterization of glycation adducts on osteocalcin

PubMed Central

Thomas, Corinne J.; Cleland, Timothy P.; Zhang, Sheng; Gundberg, Caren M.; Vashishth, Deepak

2017-01-01

Osteocalcin is an important extracellular matrix bone protein that contributes to the structural properties of bone through its interactions with hydroxyapatite mineral and with collagen I. This role may be affected by glycation, a labile modification the levels of which has been shown to correlate with bone fragility. Glycation starts with the spontaneous addition of a sugar onto a free amine group on a protein, forming an Amadori product, and then proceeds through several environment-dependent stages resulting in the formation of an advanced glycation end product. Here, we induce the first step of this modification on synthetic osteocalcin, and then use multiple mass spectrometry fragmentation techniques to determine the location of this modification. Collision-induced dissociation resulted in spectra dominated by neutral loss, and was unable to identify Amadori products. Electron-transfer dissociation showed that the Amadori product formed solely on osteocalcin’s N-terminus. This suggests that the glycation of osteocalcin is unlikely to interfere with osteocalcin’s interaction with hydroxyapatite. Instead, glycation may interfere with its interaction with collagen I or another bone protein, osteopontin. Potentially, the levels of glycated osteocalcin fragments released from bone during bone resorption could be used to assess bone quality, should the N-terminal fragments be targeted. PMID:28237256

Chemical Approaches for Structure and Function of RNA in Postgenomic Era

PubMed Central

Ro-Choi, Tae Suk; Choi, Yong Chun

2012-01-01

In the study of cellular RNA chemistry, a major thrust of research focused upon sequence determinations for decades. Structures of snRNAs (4.5S RNA I (Alu), U1, U2, U3, U4, U5, and U6) were determined at Baylor College of Medicine, Houston, Tex, in an earlier time of pregenomic era. They show novel modifications including base methylation, sugar methylation, 5′-cap structures (types 0–III) and sequence heterogeneity. This work offered an exciting problem of posttranscriptional modification and underwent numerous significant advances through technological revolutions during pregenomic, genomic, and postgenomic eras. Presently, snRNA research is making progresses involved in enzymology of snRNA modifications, molecular evolution, mechanism of spliceosome assembly, chemical mechanism of intron removal, high-order structure of snRNA in spliceosome, and pathology of splicing. These works are destined to reach final pathway of work “Function and Structure of Spliceosome” in addition to exciting new exploitation of other noncoding RNAs in all aspects of regulatory functions. PMID:22347623

Structural characterization of thioether-bridged bacteriocins.

PubMed

Lohans, Christopher T; Vederas, John C

2014-01-01

Bacteriocins are a group of ribosomally synthesized antimicrobial peptides produced by bacteria, some of which are extensively post-translationally modified. Some bacteriocins, namely the lantibiotics and sactibiotics, contain one or more thioether bridges. However, these modifications complicate the structural elucidation of these bacteriocins using conventional techniques. This review will discuss the techniques and strategies that have been applied to determine the primary structures of lantibiotics and sactibiotics. A major challenge is to identify the topology of thioether bridges in these peptides (i.e., which amino-acid residues are involved in which bridges). Edman degradation, NMR spectroscopy and tandem MS have all been commonly applied to characterize these bacteriocins, but can be incompatible with the post-translational modifications present. Chemical modifications to the modified residues, such as desulfurization and reduction, make the treated bacteriocins more compatible to analysis by these standard peptide analytical techniques. Despite their differences in structure, similar strategies have proved useful to study the structures of both lantibiotics and sactibiotics.

Iterative model building, structure refinement and density modification with the PHENIX AutoBuild wizard

PubMed Central

Terwilliger, Thomas C.; Grosse-Kunstleve, Ralf W.; Afonine, Pavel V.; Moriarty, Nigel W.; Zwart, Peter H.; Hung, Li-Wei; Read, Randy J.; Adams, Paul D.

2008-01-01

The PHENIX AutoBuild wizard is a highly automated tool for iterative model building, structure refinement and density modification using RESOLVE model building, RESOLVE statistical density modification and phenix.refine structure refinement. Recent advances in the AutoBuild wizard and phenix.refine include automated detection and application of NCS from models as they are built, extensive model-completion algorithms and automated solvent-molecule picking. Model-completion algorithms in the AutoBuild wizard include loop building, crossovers between chains in different models of a structure and side-chain optimization. The AutoBuild wizard has been applied to a set of 48 structures at resolutions ranging from 1.1 to 3.2 Å, resulting in a mean R factor of 0.24 and a mean free R factor of 0.29. The R factor of the final model is dependent on the quality of the starting electron density and is relatively independent of resolution. PMID:18094468

Environmental assessment of combustion modification controls for stationary internal combustion engines. Final report Sep 78-Jul 79

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

Lips, H.I.; Gotterba, J.A.; Lim, K.J.

1981-07-01

The report gives results of an environmental assessment of combustion modification techniques for stationary internal combustion engines, with respect to NOx control reduction effectiveness, operational impact, thermal efficiency impact, capital and annualized operating costs, and effects on emissions of pollutants other than NOx.

Beliefs about Child Support Modification Following Remarriage and Subsequent Childbirth

ERIC Educational Resources Information Center

Hans, Jason D.

2009-01-01

Framed by equity theory, fairness beliefs regarding child support modification to account for the financial impact of remarriage and subsequent childbirth were assessed. Based on a random sample of 407 Kentucky residents using a multiple segment factorial vignette approach, modification was supported by 57% of respondents following remarriage, but…

Matching medical student achievement to learning objectives and outcomes: a paradigm shift for an implemented teaching module.

PubMed

Atta, Ihab Shafek; AlQahtani, Fahd Nasser

2018-01-01

Low student achievement in a basic imaging module was the impetus for an assessment of the module. A valid, reliable, and structured Likert scale was designed to measure the degree of student satisfaction with the domains of the module, including learning objectives (LO), teaching strategy and tools (TT), assessment tools (AT), and allotted credit hours (CH). Further analysis was conducted of student dissatisfaction to determine the subdomain in which module improvement was to be implemented. Statistical analysis of data among Likert scale domains was conducted. Likert scale data showed the TT domain to be the major reason for low student achievement. Statistical studies revealed 57/117 students (48.6%) were dissatisfied with TT, compared with LO 16/117 (13.6%), AT 54/117 (46.1%), and CH 12/117 (10.2%). Significant P -values were obtained for LO vs TT ( P <0.0001), LO vs AT ( P <0.0001), LO vs CH ( P <0.03), TT vs CH ( P <0.0001), and AT vs CH ( P <0.0001). No significant difference was observed between TT and AT ( P <0.29). Regarding TT, 41/117 (34.9%) students were dissatisfied with lectures (L) compared to hospital-based teaching (HPT) 24/117 (20%), problem-based learning (PBL) 8/117 (6.8%), self-directed learning (SDL) 3/117 (2.5%), and seminars (S) 4/117 (3.4%). Significant P -values were obtained for L vs HPT ( P <0.0001), L vs PBL ( P <0.0001), L vs SDL ( P <0.0001), L vs S ( P <0.0001), HPT vs PBL ( P <0.002), HPT vs SDL ( P <0.0001), and HPT vs S ( P <0.0001). Regarding lecture modifications, student satisfaction was 78.3% compared to 52% before modification. A significant P -value ( P <0.0001) was obtained between Likert scale domains before and after modification. Lecture modification resulted in a good student response and satisfaction. The major reason for low student achievement was the teaching tools, particularly the lectures. Major modifications to lectures improved student achievement. The students and most of the teaching staff were highly satisfied with the modifications, which provided for reciprocal discussion and interaction. These results should encourage and guide other medical schools to investigate the points of weakness in their curriculum.

75 FR 47880 - Notice of Application for Approval of Discontinuance or Modification of a Railroad Signal System...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-09

... Discontinuance or Modification of a Railroad Signal System or Relief Pursuant to Title 49 Code of Federal... Administration (FRA) seeking approval for the discontinuance or modification of the signal system or relief from... & Louisville Railway, Inc., Mr. C. D. Edwards, General Supervisor of Signals & Structures, 1500 Kentucky Avenue...

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

Tripathi, S., E-mail: shilpatr3@gmail.com; Shripathi, T.; Tripathi, J.

The results are reported on solution cast PMMA-PCTFE blend films characterized using x-ray diffraction and FTIR. The nanocrystalline nature of PMMA is still seen in the blends, however, the bond modifications are clearly observed. The addition of PCTFE results in the modification in structural properties, as reflected in the XRD and FTIR spectra showing modifications in bonding as a function of PCTFE percentage.

The Stability of Post Hoc Model Modifications in Covariance Structure Models.

ERIC Educational Resources Information Center

Hutchinson, Susan R.

The work of R. MacCallum et al. (1992) was extended by examining chance modifications through a Monte Carlo simulation. The stability of post hoc model modifications was examined under varying sample size, model complexity, and severity of misspecification using 2- and 4-factor oblique confirmatory factor analysis (CFA) models with four and eight…

Pharmacy student self-perception of weight and relationship to counseling patients on lifestyle modification.

PubMed

Antworth, Allen; Maffeo, Carrie

2014-03-12

To assess the accuracy of pharmacy students' self-assessment of body mass index (BMI) and determine the relationship of this to comfort level in counseling patients regarding lifestyle modification. A prospective, observational, cohort study was conducted that included first-, second-, and third-year pharmacy students who had previously undergone training in BMI self-assessment. Data on students' weight and height were collected and a survey that contained questions on self-perception of body weight and comfort with lifestyle counseling was conducted. Perceived BMI categories (underweight, normal, overweight, and obese) were then compared to actual calculated BMI to determine the accuracy of the student's self-perception. At baseline, participants' accuracy in self-assessment of BMI was 74%, 73.3%, and 75.6% respectively, for first-, second-, and third-year students (p=0.911). Students accuracy increased but not significantly as they progressed through the curriculum (7.2% and 13.3%, respectively; p=0.470 and p=0.209). Neither accuracy in self-assessment of BMI nor students' actual BMI significantly affected students' comfort level with lifestyle modification counseling within healthy weight, overweight, or obese patient categories. However, as the patients' BMI category increased, comfort level differences were observed among students of normal and overweight categories. Patients' BMI category may be a significant barrier to pharmacy students' comfort level in providing lifestyle modification counseling. This finding suggests the need to implement curriculum changes to better prepare students for lifestyle modification counseling.

Modifications to toxic CUG RNAs induce structural stability, rescue mis-splicing in a myotonic dystrophy cell model and reduce toxicity in a myotonic dystrophy zebrafish model

DOE PAGES

deLorimier, Elaine; Coonrod, Leslie A.; Copperman, Jeremy; ...

2014-10-10

In this study, CUG repeat expansions in the 3' UTR of dystrophia myotonica protein kinase ( DMPK) cause myotonic dystrophy type 1 (DM1). As RNA, these repeats elicit toxicity by sequestering splicing proteins, such as MBNL1, into protein–RNA aggregates. Structural studies demonstrate that CUG repeats can form A-form helices, suggesting that repeat secondary structure could be important in pathogenicity. To evaluate this hypothesis, we utilized structure-stabilizing RNA modifications pseudouridine (Ψ) and 2'-O-methylation to determine if stabilization of CUG helical conformations affected toxicity. CUG repeats modified with Ψ or 2'-O-methyl groups exhibited enhanced structural stability and reduced affinity for MBNL1. Molecularmore » dynamics and X-ray crystallography suggest a potential water-bridging mechanism for Ψ-mediated CUG repeat stabilization. Ψ modification of CUG repeats rescued mis-splicing in a DM1 cell model and prevented CUG repeat toxicity in zebrafish embryos. This study indicates that the structure of toxic RNAs has a significant role in controlling the onset of neuromuscular diseases.« less

Quality assessment of protein model-structures based on structural and functional similarities

PubMed Central

2012-01-01

Background Experimental determination of protein 3D structures is expensive, time consuming and sometimes impossible. A gap between number of protein structures deposited in the World Wide Protein Data Bank and the number of sequenced proteins constantly broadens. Computational modeling is deemed to be one of the ways to deal with the problem. Although protein 3D structure prediction is a difficult task, many tools are available. These tools can model it from a sequence or partial structural information, e.g. contact maps. Consequently, biologists have the ability to generate automatically a putative 3D structure model of any protein. However, the main issue becomes evaluation of the model quality, which is one of the most important challenges of structural biology. Results GOBA - Gene Ontology-Based Assessment is a novel Protein Model Quality Assessment Program. It estimates the compatibility between a model-structure and its expected function. GOBA is based on the assumption that a high quality model is expected to be structurally similar to proteins functionally similar to the prediction target. Whereas DALI is used to measure structure similarity, protein functional similarity is quantified using standardized and hierarchical description of proteins provided by Gene Ontology combined with Wang's algorithm for calculating semantic similarity. Two approaches are proposed to express the quality of protein model-structures. One is a single model quality assessment method, the other is its modification, which provides a relative measure of model quality. Exhaustive evaluation is performed on data sets of model-structures submitted to the CASP8 and CASP9 contests. Conclusions The validation shows that the method is able to discriminate between good and bad model-structures. The best of tested GOBA scores achieved 0.74 and 0.8 as a mean Pearson correlation to the observed quality of models in our CASP8 and CASP9-based validation sets. GOBA also obtained the best result for two targets of CASP8, and one of CASP9, compared to the contest participants. Consequently, GOBA offers a novel single model quality assessment program that addresses the practical needs of biologists. In conjunction with other Model Quality Assessment Programs (MQAPs), it would prove useful for the evaluation of single protein models. PMID:22998498

Biophysical analysis of the effect of chemical modification by 4-oxononenal on the structure, stability, and function of binding immunoglobulin protein (BiP)

PubMed Central

Shah, Dinen D.; Singh, Surinder M.; Dzieciatkowska, Monika

2017-01-01

Binding immunoglobulin protein (BiP) is a molecular chaperone important for the folding of numerous proteins, which include millions of immunoglobulins in human body. It also plays a key role in the unfolded protein response (UPR) in the endoplasmic reticulum. Free radical generation is a common phenomenon that occurs in cells under healthy as well as under stress conditions such as ageing, inflammation, alcohol consumption, and smoking. These free radicals attack the cell membranes and generate highly reactive lipid peroxidation products such as 4-oxononenal (4-ONE). BiP is a key protein that is modified by 4-ONE. In this study, we probed how such chemical modification affects the biophysical properties of BiP. Upon modification, BiP shows significant tertiary structural changes with no changes in its secondary structure. The protein loses its thermodynamic stability, particularly, that of the nucleotide binding domain (NBD) where ATP binds. In terms of function, the modified BiP completely loses its ATPase activity with decreased ATP binding affinity. However, modified BiP retains its immunoglobulin binding function and its chaperone activity of suppressing non-specific protein aggregation. These results indicate that 4-ONE modification can significantly affect the structure-function of key proteins such as BiP involved in cellular pathways, and provide a molecular basis for how chemical modifications can result in the failure of quality control mechanisms inside the cell. PMID:28886061

Chemical modification of citrus pectin: Structural, physical and rheologial implications.

PubMed

Fracasso, Aline Francielle; Perussello, Camila Augusto; Carpiné, Danielle; Petkowicz, Carmen Lúcia de Oliveira; Haminiuk, Charles Windson Isidoro

2018-04-01

The present study aimed to investigate the physical, structural and rheological modifications caused by the chemical modification process of citrus pectin. Therefore, three commercial citrus pectins with different degree of esterification were chemically modified by sequential alkali and acidic hydrolytic process to produce modified citrus pectins (MCP) with special properties. The molar mass (M w ), degree of esterification (DE), monosaccharide composition, 13 C NMR spectra, homogeneity, morphology (SEM) and rheological behavior of both native and modified citrus pectins (MCP) were investigated. The chemical modification reduced the acid uronic content (up to 28.3%) and molar mass (up to 29.98%), however, showed little influence on the degree of esterification of native pectins. Modified citrus pectins presented higher amounts of neutral monosaccharides, mainly galactose, arabinose and rhamnose, typical of the Ramnogalacturonana-I (RG-I) region. Rheological tests indicated that the native and modified citrus pectins presented pseudoplastic behavior, however, the MCP samples were less viscous, compared to the native ones. Modified samples presented better dissolution in water and less strong gels, with good stability during oscillatory shearing at 25°C. This study aims to better understand the implications that chemical modifications may impose on the structure of citrus pectins. Copyright © 2017 Elsevier B.V. All rights reserved.

Introduction to the thematic minireview series on redox-active protein modifications and signaling.

PubMed

Banerjee, Ruma

2013-09-13

The dynamics of redox metabolism necessitate cellular strategies for sensing redox changes and for responding to them. A common mechanism for receiving and transmitting redox changes is via reversible modifications of protein cysteine residues. A plethora of cysteine modifications have been described, including sulfenylation, glutathionylation, and disulfide formation. These post-translational modifications have the potential to alter protein structure and/or function and to modulate cellular processes ranging from division to death and from circadian rhythms to secretion. The focus of this thematic minireview series is cysteine modifications in response to reactive oxygen and nitrogen species.

Effect of ion-beam treatment on structure and fracture resistance of 12Cr1MoV steel under static, cyclic and dynamic loading

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

Panin, S. V., E-mail: svp@ispms.tsc.ru; Vlasov, I. V., E-mail: good0@yandex.ru; Sergeev, V. P., E-mail: retc@ispms.tsc.ru

2015-10-27

Features of the structure and properties modification of 12Cr1MoV steel subjected to irradiation by zirconium ion beam have been investigated with the use of optical and electron microscopy as well as microhardness measurement. It has been shown that upon treatment the structure modification occurred across the entire cross-section of specimens with the thickness of 1 mm. Changes in the mechanical properties of these specimens under static, cyclic and impact loading are interpreted in terms of identified structure changes.

Synthesis of (−)-Pseudotabersonine, (−)-Pseudovincadifformine, and (+)-Coronaridine Enabled by Photoredox Catalysis in Flow

PubMed Central

2015-01-01

Natural product modification with photoredox catalysis allows for mild, chemoselective access to a wide array of related structures in complex areas of chemical space, providing the possibility for novel structural motifs as well as useful quantities of less abundant congeners. While amine additives have been used extensively as stoichiometric electron donors for photocatalysis, the controlled modification of amine substrates through single-electron oxidation is ideal for the synthesis and modification of alkaloids. Here, we report the conversion of the amine (+)-catharanthine into the natural products (−)-pseudotabersonine, (−)-pseudovincadifformine, and (+)-coronaridine utilizing visible light photoredox catalysis. PMID:25003992

Assessing Chemical Transformation of Reactive, Interfacial Thin Films Made of End-Tethered Poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) Chains

DOE PAGES

Aden, Bethany; Kite, Camille M.; Hopkins, Benjamin W.; ...

2017-01-24

Designing thin films or surface scaffolds with an appropriate display of chemical functionality is useful for biomedical applications, sensing platforms, adhesives, and barrier coatings. Relationships between the structural characteristics of model thin films based on reactive poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) brushes and the amount and distribution of primary amines used to chemically functionalize these layers in situ are quantitatively detailed via neutron reflectometry and compared with results from ellipsometry. After functionalization, the PVDMA brush thickness increases as a result of the primary amines reacting with the azlactone rings. Both techniques show that the extent of functionalization by small-molecule amines depends onmore » the size of the amine, the grafting density of brush chains, and their molecular weight. However, constrained analysis of neutron reflectivity data predicated on that technique’s sensitivity to isotopic substitution and its ability to resolve structure at the nanoscale shows that the extent of functionalization is not accurately represented by the average extent of functionalization determined from ellipsometric thickness: reactive modification is not uniform, even in modestly dense brushes, except when the penetrant is small. In addition, there appears to be a loss of PVDMA chains during functionalization, attributed to chain scission resulting from additional stretching brought about by functionalization. In conclusion, these findings provide unprecedented insight into the alteration of surface properties by reactive modification and broadly support efforts to produce tailored surfaces in which properties such as friction, colloidal stability, adhesion, wettability, and biocompatibility can be modulated in situ by chemical modification.« less

Advanced glycation end products induce differential structural modifications and fibrillation of albumin

NASA Astrophysics Data System (ADS)

Awasthi, Saurabh; Sankaranarayanan, Kamatchi; Saraswathi, N. T.

2016-06-01

Glycation induced amyloid fibrillation is fundamental to the development of many neurodegenerative and cardiovascular complications. Excessive non-enzymatic glycation in conditions such as hyperglycaemia results in the increased accumulation of advanced glycation end products (AGEs). AGEs are highly reactive pro-oxidants, which can lead to the activation of inflammatory pathways and development of oxidative stress. Recently, the effect of non-enzymatic glycation on protein structure has been the major research area, but the role of specific AGEs in such structural alteration and induction of fibrillation remains undefined. In this study, we determined the specific AGEs mediated structural modifications in albumin mainly considering carboxymethyllysine (CML), carboxyethyllysine (CEL), and argpyrimidine (Arg-P) which are the major AGEs formed in the body. We studied the secondary structural changes based on circular dichroism (CD) and spectroscopic analysis. The AGEs induced fibrillation was determined by Congo red binding and examination of scanning and transmission electron micrographs. The amyloidogenic regions in the sequence of BSA were determined using FoldAmyloid. It was observed that CEL modification of BSA leads to the development of fibrillar structures, which was evident from both secondary structure changes and TEM analysis.

District Self-Assessment Tool: For Modification of Collective Bargaining Agreements to Achieve Flexible Conditions for School Turnaround

ERIC Educational Resources Information Center

Mass Insight Education (NJ1), 2011

2011-01-01

The District Self-Assessment Tool is designed to support districts, unions and Lead Partners, when analyzing their existing collective bargaining agreement (CBA) with the intention of making targeted modifications to support the implementation of dramatic reform in the district's lowest-performing schools. By outlining objectives and suggested…

The combined use of analytical tools for exploring tetanus toxin and tetanus toxoid structures.

PubMed

Bayart, Caroline; Peronin, Sébastien; Jean, Elisa; Paladino, Joseph; Talaga, Philippe; Borgne, Marc Le

2017-06-01

Aldehyde detoxification is a process used to convert toxin into toxoid for vaccine applications. In the case of tetanus toxin (TT), formaldehyde is used to obtain the tetanus toxoid (TTd), which is used either for the tetanus vaccine or as carrier protein in conjugate vaccines. Several studies have already been conducted to better understand the exact mechanism of this detoxification. Those studies led to the identification of a number of formaldehyde-induced modifications on lab scale TTd samples. To obtain greater insights of the changes induced by formaldehyde, we used three industrial TTd batches to identify repeatable modifications in the detoxification process. Our strategy was to combine seven analytical tools to map these changes. Mass spectrometry (MS), colorimetric test and amino acid analysis (AAA) were used to study modifications on amino acids. SDS-PAGE, asymmetric flow field flow fractionation (AF4), fluorescence spectroscopy and circular dichroism (CD) were used to study formaldehyde modifications on the whole protein structure. We identified 41 formaldehyde-induced modifications across the 1315 amino acid primary sequence of TT. Of these, five modifications on lysine residues were repeatable across TTd batches. Changes in protein conformation were also observed using SDS-PAGE, AF4 and CD techniques. Each analytical tool brought a piece of information regarding formaldehyde induced-modifications, and all together, these methods provided a comprehensive overview of the structural changes that occurred with detoxification. These results could be the first step leading to site-directed TT mutagenesis studies that may enable the production of a non-toxic equivalent protein without using formaldehyde. Copyright © 2017 Elsevier B.V. All rights reserved.

Glycan Reader is improved to recognize most sugar types and chemical modifications in the Protein Data Bank.

PubMed

Park, Sang-Jun; Lee, Jumin; Patel, Dhilon S; Ma, Hongjing; Lee, Hui Sun; Jo, Sunhwan; Im, Wonpil

2017-10-01

Glycans play a central role in many essential biological processes. Glycan Reader was originally developed to simplify the reading of Protein Data Bank (PDB) files containing glycans through the automatic detection and annotation of sugars and glycosidic linkages between sugar units and to proteins, all based on atomic coordinates and connectivity information. Carbohydrates can have various chemical modifications at different positions, making their chemical space much diverse. Unfortunately, current PDB files do not provide exact annotations for most carbohydrate derivatives and more than 50% of PDB glycan chains have at least one carbohydrate derivative that could not be correctly recognized by the original Glycan Reader. Glycan Reader has been improved and now identifies most sugar types and chemical modifications (including various glycolipids) in the PDB, and both PDB and PDBx/mmCIF formats are supported. CHARMM-GUI Glycan Reader is updated to generate the simulation system and input of various glycoconjugates with most sugar types and chemical modifications. It also offers a new functionality to edit the glycan structures through addition/deletion/modification of glycosylation types, sugar types, chemical modifications, glycosidic linkages, and anomeric states. The simulation system and input files can be used for CHARMM, NAMD, GROMACS, AMBER, GENESIS, LAMMPS, Desmond, OpenMM, and CHARMM/OpenMM. Glycan Fragment Database in GlycanStructure.Org is also updated to provide an intuitive glycan sequence search tool for complex glycan structures with various chemical modifications in the PDB. http://www.charmm-gui.org/input/glycan and http://www.glycanstructure.org. wonpil@lehigh.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Evaluating the online platform of a blended-learning pharmacist continuing education degree program.

PubMed

Wilbur, Kerry

2016-01-01

Background Distance-based continuing education opportunities are increasingly embraced by health professionals worldwide. Methods To evaluate the online component of a blended-learning degree program for pharmacists, we conducted a structured self-assessment and peer review using an instrument systematically devised according to Moore's principles of transactional distance. The web-based platform for 14 courses was reviewed by both local and external faculty, followed by shared reflection of individual and aggregate results. Results Findings indicated a number of course elements for modification to enhance the structure, dialog, and autonomy of the student learning experience. Conclusion Our process was an important exercise in quality assurance and is worthwhile for other health disciplines developing and delivering distance-based content to pursue.

Evaluating the online platform of a blended-learning pharmacist continuing education degree program

PubMed Central

Wilbur, Kerry

2016-01-01

Background Distance-based continuing education opportunities are increasingly embraced by health professionals worldwide. Methods To evaluate the online component of a blended-learning degree program for pharmacists, we conducted a structured self-assessment and peer review using an instrument systematically devised according to Moore's principles of transactional distance. The web-based platform for 14 courses was reviewed by both local and external faculty, followed by shared reflection of individual and aggregate results. Results Findings indicated a number of course elements for modification to enhance the structure, dialog, and autonomy of the student learning experience. Conclusion Our process was an important exercise in quality assurance and is worthwhile for other health disciplines developing and delivering distance-based content to pursue. PMID:27282277

An aeroelastician's perspective of wind tunnel and flight experiences with active control of structural response and stability

NASA Technical Reports Server (NTRS)

Hanson, P. W.

1984-01-01

Active controls technology is assessed based on a review of most of the wind-tunnel and flight tests and actual applications of active control concepts since the late sixties. The distinction is made between so-called ""rigid-body'' active control functions and those that involve significant modification of structural elastic response or stability. Both areas are reviewed although the focus is on the latter area. The basic goals and major results of the various studies or applications are summarized, and the anticipated use of active controls on current and near-future research and demonstration aircraft is discussed. Some of the ""holes'' remaining in the feasbility/benefits demonstration of active controls technology are examined.

Evaluating the online platform of a blended-learning pharmacist continuing education degree program.

PubMed

Wilbur, Kerry

2016-01-01

Distance-based continuing education opportunities are increasingly embraced by health professionals worldwide. To evaluate the online component of a blended-learning degree program for pharmacists, we conducted a structured self-assessment and peer review using an instrument systematically devised according to Moore's principles of transactional distance. The web-based platform for 14 courses was reviewed by both local and external faculty, followed by shared reflection of individual and aggregate results. Findings indicated a number of course elements for modification to enhance the structure, dialog, and autonomy of the student learning experience. Our process was an important exercise in quality assurance and is worthwhile for other health disciplines developing and delivering distance-based content to pursue.

Nanoscale surface modification of Li-rich layered oxides for high-capacity cathodes in Li-ion batteries

NASA Astrophysics Data System (ADS)

Lan, Xiwei; Xin, Yue; Wang, Libin; Hu, Xianluo

2018-03-01

Li-rich layered oxides (LLOs) have been developed as a high-capacity cathode material for Li-ion batteries, but the structural complexity and unique initial charging behavior lead to several problems including large initial capacity loss, capacity and voltage fading, poor cyclability, and inferior rate capability. Since the surface conditions are critical to electrochemical performance and the drawbacks, nanoscale surface modification for improving LLO's properties is a general strategy. This review mainly summarizes the surface modification of LLOs and classifies them into three types of surface pre-treatment, surface gradient doping, and surface coating. Surface pre-treatment usually introduces removal of Li2O for lower irreversible capacity while surface doping is aimed to stabilize the structure during electrochemical cycling. Surface coating layers with different properties, protective layers to suppress the interface side reaction, coating layers related to structural transformation, and electronic/ionic conductive layers for better rate capability, can avoid the shortcomings of LLOs. In addition to surface modification for performance enhancement, other strategies can also be investigated to achieve high-performance LLO-based cathode materials.

Alternative approaches used to assess structural changes of natural zircon caused by heat treatment

NASA Astrophysics Data System (ADS)

Huong, L. T. T.; Thuyet, N. T. M.; Phan, T. L.; Tran, N.; Toan, D. N.; Thang, P. D.; Huy, B. T.

2018-03-01

It is known that large changes in the crystal structure of zircon (ZrSiO4) can be assessed through the linewidth of the characteristic Raman mode (Δν3) at 1008 cm-1. However, the use of Δν3 to assess small changes caused by heat treatment at temperatures below its decomposition temperature of 1670 °C is difficult. The present work points out that the combination of X-ray diffraction (XRD) analyses, and photoluminescence (PL) and Raman (RS) measurements with different excitation wavelengths is an effective approach to solve the above problem. In this context, we have selected natural zircon containing some rare-earth (RE) impurities, and then studied the changes in its crystal structure caused by heat treatment at temperatures Tan=400-1600 °C. XRD analyses reveal that small modifications of the unit-cell parameters occur as Tan>600 °C. Taking the intensity ratios of the ν3 mode to RE-related emissions (Iν3/IRE) or the PL intensity ratios between RE-related emissions into consideration, the similar results in good agreement with the XRD analyses are also found. We believe that the small structural changes are related to the migration and redistribution of defects and impurities, and re-crystallization of zircon. This could be further confirmed though the relation between paramagnetic and ferromagnetic signals when Tan changes.

Factor structure of the autonomy preference index in people with severe mental illness.

PubMed

Bonfils, Kelsey A; Adams, Erin L; Mueser, Kim T; Wright-Berryman, Jennifer L; Salyers, Michelle P

2015-08-30

People vary in the amount of control they want to exercise over decisions about their healthcare. Given the importance of patient-centered care, accurate measurement of these autonomy preferences is critical. This study aimed to assess the factor structure of the Autonomy Preference Index (API), used widely in general healthcare, in individuals with severe mental illness. Data came from two studies of people with severe mental illness (N=293) who were receiving mental health and/or primary care/integrated care services. Autonomy preferences were assessed with the API regarding both psychiatric and primary care services. Confirmatory factor analysis was used to evaluate fit of the hypothesized two-factor structure of the API (decision-making autonomy and information-seeking autonomy). Results indicated the hypothesized structure for the API did not adequately fit the data for either psychiatric or primary care services. Three problematic items were dropped, resulting in adequate fit for both types of treatment. These results suggest that with relatively minor modifications the API has an acceptable factor structure when asking people with severe mental illness about their preferences to be involved in decision-making. The modified API has clinical and research utility for this population in the burgeoning field of autonomy in patient-centered healthcare. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

KSC-03pd0262

NASA Image and Video Library

2003-02-04

KENNEDY SPACE CENTER, FLA. -- United Space Alliance (USA) technicians install thermal protection system tiles on Space Shuttle Discovery. Discovery is undergoing its Orbiter Major Modification Period, a regularly scheduled structural inspection and modification downtime, which began in September 2002. .

Evaluation of cab car crashworthiness design modifications

DOT National Transportation Integrated Search

1997-03-01

A study was conducted to evaluate the effectiveness of structural : modifications to rail cab cars for increased crashworthiness protection in train collisions. The crashworthiness benefits were calculated based on a particular design's ability to pr...

In silico assessment of phosphorylation and O-β-GlcNAcylation sites in human NPC1 protein critical for Ebola virus entry.

PubMed

Basharat, Zarrin; Yasmin, Azra

2015-08-01

Ebola is a highly pathogenic enveloped virus responsible for deadly outbreaks of severe hemorrhagic fever. It enters human cells by binding a multifunctional cholesterol transporter Niemann-Pick C1 (NPC1) protein. Post translational modification (PTM) information for NPC1 is crucial to understand Ebola virus (EBOV) entry and action due to changes in phosphorylation or glycosylation at the binding site. It is difficult and costly to experimentally assess this type of interaction, so in silico strategy was employed. Identification of phosphorylation sites, including conserved residues that could be possible targets for 21 predicted kinases was followed by interplay study between phosphorylation and O-β-GlcNAc modification of NPC1. Results revealed that only 4 out of 48 predicted phosphosites exhibited O-β-GlcNAc activity. Predicted outcomes were integrated with residue conservation and 3D structural information. Three Yin Yang sites were located in the α-helix regions and were conserved in studied vertebrate and mammalian species. Only one modification site S425 was found in β-turn region located near the N-terminus of NPC1 and was found to differ in pig, mouse, cobra and humans. The predictions suggest that Yin Yang sites may not be important for virus attachment to NPC1, whereas phosphosite 473 may be important for binding and hence entry of Ebola virus. This information could be useful in addressing further experimental studies and therapeutic strategies targeting PTM events in EBOV entry. Copyright © 2015 Elsevier B.V. All rights reserved.

A high-throughput and rapid computational method for screening of RNA post-transcriptional modifications that can be recognized by target proteins.

PubMed

Orr, Asuka A; Gonzalez-Rivera, Juan C; Wilson, Mark; Bhikha, P Reena; Wang, Daiqi; Contreras, Lydia M; Tamamis, Phanourios

2018-02-01

There are over 150 currently known, highly diverse chemically modified RNAs, which are dynamic, reversible, and can modulate RNA-protein interactions. Yet, little is known about the wealth of such interactions. This can be attributed to the lack of tools that allow the rapid study of all the potential RNA modifications that might mediate RNA-protein interactions. As a promising step toward this direction, here we present a computational protocol for the characterization of interactions between proteins and RNA containing post-transcriptional modifications. Given an RNA-protein complex structure, potential RNA modified ribonucleoside positions, and molecular mechanics parameters for capturing energetics of RNA modifications, our protocol operates in two stages. In the first stage, a decision-making tool, comprising short simulations and interaction energy calculations, performs a fast and efficient search in a high-throughput fashion, through a list of different types of RNA modifications categorized into trees according to their structural and physicochemical properties, and selects a subset of RNA modifications prone to interact with the target protein. In the second stage, RNA modifications that are selected as recognized by the protein are examined in-detail using all-atom simulations and free energy calculations. We implement and experimentally validate this protocol in a test case involving the study of RNA modifications in complex with Escherichia coli (E. coli) protein Polynucleotide Phosphorylase (PNPase), depicting the favorable interaction between 8-oxo-7,8-dihydroguanosine (8-oxoG) RNA modification and PNPase. Further advancement of the protocol can broaden our understanding of protein interactions with all known RNA modifications in several systems. Copyright © 2018 Elsevier Inc. All rights reserved.

Examination of arthritis-related work place activity limitations and intermittent disability over four-and-a-half years and its relationship to job modifications and outcomes.

PubMed

Gignac, Monique A M; Cao, Xingshan; Tang, Kenneth; Beaton, Dorcas E

2011-07-01

To examine the type, degree, and episodic nature of arthritis-related work place activity limitations and the consistency of the relationship of activity limitations to job modifications and work place outcomes. Using an interviewer-administered structured questionnaire, individuals with osteoarthritis (OA) or inflammatory arthritis (IA) were interviewed at 4 time points, 18 months apart. At baseline, all participants (n = 490; 381 women, 109 men) were employed. Respondents were recruited using community advertising and from rheumatology and rehabilitation clinics. The Workplace Activity Limitations Scale (WALS) assessed arthritis-related disability with job tasks. Job modifications/accommodations (e.g., scheduling changes), work place outcomes (e.g., absenteeism), demographics, illness, and work context were also measured. Repeated cross-sectional logistic regressions examined levels of WALS disability with job modifications and outcomes at each time point. Similar levels of activity limitations were found comparing OA and IA with fewer difficulties with global aspects of work (e.g., scheduling) than with specific tasks (e.g., working with hands). Three-quarters of the participants had episodic or intermittent WALS difficulty over time. Medium and high levels of work place activity limitations were significantly associated with job modifications, and high WALS difficulty was consistently related to negative work outcomes. Many individuals with arthritis report some difficulty with work place activities. However, these difficulties are often intermittent and may not result in changes to work productivity until they are consistently high. This is important for designing work place interventions and for employers, insurers, and the government to understand to avoid viewing individuals with arthritis as a permanent drain on work place and health resources. Copyright © 2011 by the American College of Rheumatology.

[Preparation of honeycombed monolithic zeolite and hydrophobic modification with SiCl4].

PubMed

Wang, Xi-Qin; Li, Kai; Wei, Bing; Luan, Zhi-Qiang

2011-12-01

A kind of hydrophobic zeolitic monolith were prepared by mixing HY/ZSM-5, additives and water, followed by processes of extrusion and drying, and then hydrophobic modification with SiCl4. The structures and properties of the adsorbent were examined by nitrogen adsorption and desorption measurement, XRD, and benzene adsorption experiment. The results show that those adsorbents possess hierarchical pore structures and excellent hydrophobicity.

Composition, structure, physicochemical properties, and modifications of cassava starch.

PubMed

Zhu, Fan

2015-05-20

Cassava is highly tolerant to harsh climatic conditions and has great productivity on marginal lands. The supply of cassava starch, the major component of the root, is thus sustainable and cheap. This review summarizes the current knowledge of the composition, physical and chemical structures, physicochemical properties, nutritional quality, and modifications of cassava starch. Research opportunities to better understand this starch are provided. Copyright © 2014 Elsevier Ltd. All rights reserved.

Variation of the chemical reactivity of Thermus thermophilus HB8 ribosomal proteins as a function of pH.

PubMed

Running, William E; Reilly, James P

2010-10-01

Ribosomes occupy a central position in cellular metabolism, converting stored genetic information into active cellular machinery. Ribosomal proteins modulate both the intrinsic function of the ribosome and its interaction with other cellular complexes, such as chaperonins or the signal recognition particle. Chemical modification of proteins combined with mass spectrometric detection of the extent and position of covalent modifications is a rapid, sensitive method for the study of protein structure and flexibility. By altering the pH of the solution, we have induced non-denaturing changes in the structure of bacterial ribosomal proteins and detected these conformational changes by covalent labeling. Changes in ribosomal protein modification across a pH range from 6.6 to 8.3 are unique to each protein, and correlate with their structural environment in the ribosome. Lysine residues whose extent of modification increases as a function of increasing pH are on the surface of proteins, but in close proximity either to glutamate and aspartate residues, or to rRNA backbone phosphates. Increasing pH disrupts tertiary and quaternary interactions mediated by hydrogen bonding or ionic interactions, and regions of protein structure whose conformations are sensitive to these changes are of potential importance in modulating the flexibility of the ribosome or its interaction with other cellular complexes.

Structure modulation of helix 69 from Escherichia coli 23S ribosomal RNA by pseudouridylations.

PubMed

Jiang, Jun; Aduri, Raviprasad; Chow, Christine S; SantaLucia, John

2014-04-01

Helix 69 (H69) is a 19-nt stem-loop region from the large subunit ribosomal RNA. Three pseudouridine (Ψ) modifications clustered in H69 are conserved across phylogeny and known to affect ribosome function. To explore the effects of Ψ on the conformations of Escherichia coli H69 in solution, nuclear magnetic resonance spectroscopy was used to reveal the structural differences between H69 with (ΨΨΨ) and without (UUU) Ψ modifications. Comparison of the two structures shows that H69 ΨΨΨ has the following unique features: (i) the loop region is closed by a Watson-Crick base pair between Ψ1911 and A1919, which is potentially reinforced by interactions involving Ψ1911N1H and (ii) Ψ modifications at loop residues 1915 and 1917 promote base stacking from Ψ1915 to A1918. In contrast, the H69 UUU loop region, which lacks Ψ modifications, is less organized. Structure modulation by Ψ leads to alteration in conformational behavior of the 5' half of the H69 loop region, observed as broadening of C1914 non-exchangeable base proton resonances in the H69 ΨΨΨ nuclear magnetic resonance spectra, and plays an important biological role in establishing the ribosomal intersubunit bridge B2a and mediating translational fidelity.

Satiety Innovations: Food Products to Assist Consumers with Weight Loss, Evidence on the Role of Satiety in Healthy Eating: Overview and In Vitro Approximation.

PubMed

López-Nicolás, Rubén; Marzorati, Massimo; Scarabottolo, Lia; Halford, Jason C G; Johnstone, Alexandra M; Frontela-Saseta, Carmen; Sanmartín, Angel M; Ros-Berruezo, Gaspar; Harrold, Joanne A

2016-03-01

The prevalence of overweight and obesity is increasing globally, driven by the availability of energy-dense palatable foods. Most dietary strategies fail because of hunger generated by calorie restriction, and interventions that specifically control hunger and/or promote fullness may aid success. Current consumers have a limited choice of satiety-enhancing products with proven health benefits, and innovative ways to produce new foods (as structural modification) to enhance satiety/satiation may provide new opportunities. However, this potential is hindered by the cost of product testing. Within the SATIN-SATiety INnovation project-an in vitro platform has been developed to offer a cost-effective means of assessing the potential satiation/satiety effect of novel foods. This combines in vitro technologies to assess changes in colonic bacteria metabolism, appetite hormone release and the stability and bioavailability of active compounds in the new products/ingredients. This article provides a brief review of nutrients for which an impact on short-term appetite regulation has been demonstrated, and a summary of the changes to food structure which can be used to produce a change in appetite expression. Furthermore, the SATIN in vitro platform is discussed as a means of assessing the impact of nutritional and structural manipulations on appetite.

Advances in chemical synthesis of structurally modified bioactive RNAs.

PubMed

Li, Ziyuan; Zhou, Haipin; Wu, Xiaoming; Yao, Hequan

2013-01-01

Methods for the chemical synthesis of RNA have been available for almost half century, and presently, RNA could be chemically synthesized by automated synthesizers, using protected ribonucleosides preactivated as phosphoramidites, which has already been covered by many reviews. In addition to advancement on synthetic methods, a variety of modifications have also been made on the synthesized oligonucleotides, and previous reviews on the general synthesis of RNAs have not covered this area. In this tutorial review, three types of modifications have been summarized standing at the viewpoint of medicinal chemistry: (1) modifications on nucleobase, comprising substituent introduction and replacement with pseudobase; (2) modifications on ribose, consisting of modifications on the 2', 3' or 5'-position, alternation of configuration, and conformational restriction on ribose; (3) modifications on internucleoside linkages, including amide, formacetal, sulfide, sulfone, ether, phosphorothiolate and phosphorothioate linkages. Synthetic methods achieving these modifications along with the functions or values of these modifications have also been discussed and commented on.

Structure-activity relationship of karrikin germination stimulants.

PubMed

Flematti, Gavin R; Scaffidi, Adrian; Goddard-Borger, Ethan D; Heath, Charles H; Nelson, David C; Commander, Lucy E; Stick, Robert V; Dixon, Kingsley W; Smith, Steven M; Ghisalberti, Emilio L

2010-08-11

Karrikins (2H-furo[2,3-c]pyran-2-ones) are potent smoke-derived germination promoters for a diverse range of plant species but, to date, their mode of action remains unknown. This paper reports the structure-activity relationship of numerous karrikin analogues to increase understanding of the key structural features of the molecule that are required for biological activity. The results demonstrate that modification at the C5 position is preferred over modification at the C3, C4, or C7 positions for retaining the highest bioactivity.

Phosphorylation Interferes with Maturation of Amyloid-β Fibrillar Structure in the N Terminus.

PubMed

Rezaei-Ghaleh, Nasrollah; Kumar, Sathish; Walter, Jochen; Zweckstetter, Markus

2016-07-29

Neurodegeneration is characterized by the ubiquitous presence of modifications in protein deposits. Despite their potential significance in the initiation and progression of neurodegenerative diseases, the effects of posttranslational modifications on the molecular properties of protein aggregates are largely unknown. Here, we study the Alzheimer disease-related amyloid-β (Aβ) peptide and investigate how phosphorylation at serine 8 affects the structure of Aβ aggregates. Serine 8 is shown to be located in a region of high conformational flexibility in monomeric Aβ, which upon phosphorylation undergoes changes in local conformational dynamics. Using hydrogen-deuterium exchange NMR and fluorescence quenching techniques, we demonstrate that Aβ phosphorylation at serine 8 causes structural changes in the N-terminal region of Aβ aggregates in favor of less compact conformations. Structural changes induced by serine 8 phosphorylation can provide a mechanistic link between phosphorylation and other biological events that involve the N-terminal region of Aβ aggregates. Our data therefore support an important role of posttranslational modifications in the structural polymorphism of amyloid aggregates and their modulatory effect on neurodegeneration. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Floor-fractured crater models of the Sudbury structure, Canada

NASA Technical Reports Server (NTRS)

Wichman, R. W.; Schultz, P. H.

1992-01-01

The Sudbury structure in Ontario, Canada, is one of the oldest and largest impact structures recognized in the geological record. It is also one of the most extensively deformed and volcanically modified impact structures on Earth. Although few other terrestrial craters are recognized as volcanically modified, numerous impact craters on the Moon have been volcanically and tectonically modified and provide possible analogs for the observed pattern of modification at Sudbury. We correlate the pattern of early deformation at Sudbury to fracture patterns in two alternative lunar analogs and then use these analogs both to estimate the initial size of the Sudbury structure and to model the nature of early crater modification at Sudbury.

Prediction of possible CaMnO3 modifications using an ab initio minimization data-mining approach.

PubMed

Zagorac, Jelena; Zagorac, Dejan; Zarubica, Aleksandra; Schön, J Christian; Djuris, Katarina; Matovic, Branko

2014-10-01

We have performed a crystal structure prediction study of CaMnO3 focusing on structures generated by octahedral tilting according to group-subgroup relations from the ideal perovskite type (Pm\\overline 3 m), which is the aristotype of the experimentally known CaMnO3 compound in the Pnma space group. Furthermore, additional structure candidates have been obtained using data mining. For each of the structure candidates, a local optimization on the ab initio level using density-functional theory (LDA, hybrid B3LYP) and the Hartree--Fock (HF) method was performed, and we find that several of the modifications may be experimentally accessible. In the high-pressure regime, we identify a post-perovskite phase in the CaIrO3 type, not previously observed in CaMnO3. Similarly, calculations at effective negative pressure predict a phase transition from the orthorhombic perovskite to an ilmenite-type (FeTiO3) modification of CaMnO3.

Structural analyses of EBER1 and EBER2 ribonucleoprotein particles present in Epstein-Barr virus-infected cells.

PubMed Central

Glickman, J N; Howe, J G; Steitz, J A

1988-01-01

The ribonucleoprotein (RNP) particles containing the Epstein-Barr virus-associated small RNAs EBER1 and EBER2 were analyzed to determine their RNA secondary structures and sites of RNA-protein interaction. The secondary structures were probed with nucleases and by chemical modification with single-strand-specific reagents, and the sites of modification or cleavage were mapped by primer extension. These data were used to develop secondary structures for the two RNAs, and likely sites of close RNA-protein contact were identified by comparing modification patterns for naked RNA and RNA in RNP particles. In addition, sites of interaction between each Epstein-Barr virus-encoded RNA (EBER) and the La antigen were identified by analyzing RNA fragments resistant to digestion by RNase A or T1 after immunoprecipitation by an anti-La serum sample from a lupus patient. Our results confirm earlier findings that the La protein binds to the 3' terminus of each molecule. Possible functions for the EBER RNPs are discussed. Images PMID:2828685

Chemical Structure and Surface Modification of Dendritic Nanomaterials Tailored for Therapeutic and Diagnostic Applications.

PubMed

Myung, Ja Hye; Hsu, Hao-Jui; Bugno, Jason; Tam, Kevin A; Hong, Seungpyo

2017-01-01

Dendritic nanomaterials have attracted a great deal of scientific interest due to their high capacity for multifunctionalization and potential in various biomedical applications, such as drug/gene delivery and diagnostic systems. Depending on the molecular structure and starting monomers, several different types of dendrimers have been developed, including poly(amidoamine) (PAMAM), poly(propylenimine) (PPI), and poly(L-lysine) (PLL) dendrimers, in addition to modified dendritic nanomaterials, such as Janus dendrimers and dendritic block copolymers. The chemical structure and surface modification of dendritic nanomaterials have been found to play a critical role in governing their biological behaviors. In this review, we present a comprehensive overview focusing on the synthesis and chemical structures of dendrimers and modified dendritic nanomaterials that are currently being investigated for drug delivery, gene delivery, and diagnostic applications. In addition, the impact of chemical surface modification and functionalization to the dendritic nanomaterials on their therapeutic and diagnostic applications are highlighted. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

High temperature extended x-ray absorption fine structure study of multiferroic BiFeO3

NASA Astrophysics Data System (ADS)

Raghavendra Reddy, V.; Meneghini, Carlo; Kothari, Deepti; Gupta, Ajay; Aquilanti, Giuliana

2012-08-01

Local atomic structure modifications around Fe atoms in polycrystalline multiferroic BiFeO3 are studied by Fe K edge x-ray absorption spectroscopy as a function of temperature across the Néel temperature (TN = 643 K) in order to reveal local structure modifications related to the magnetic transition. This work demonstrates that on crossing TN the local structure around Fe shows peculiar changes: the Fe-O bond lengths get shorter, the ligand symmetry increases and the Fe-O bond length disorder (σ2) deviates from Debye behaviour. These results suggest that the structural transition at the ferroelectric Curie temperature (TC = 1103 K) is anticipated by early local rearrangement of the structure starting already at TN.

Hirsutane-type sesquiterpenes with uncommon modifications from three basidiomycetes.

PubMed

Liermann, Johannes C; Schüffler, Anja; Wollinsky, Beate; Birnbacher, Judith; Kolshorn, Heinz; Anke, Timm; Opatz, Till

2010-05-07

From three basidiomycetes, Xeromphalina sp., Stereum sp., and Pleurocybella porrigens, six triquinane sesquiterpenes with unprecendented modifications and a rearranged sesquiterpene related to coriolin C have been isolated. Their isolation, structure elucidation, and biological evaluation are described.

Structure and Modification of Electrode Materials for Protein Electrochemistry.

PubMed

Jeuken, Lars J C

The interactions between proteins and electrode surfaces are of fundamental importance in bioelectrochemistry, including photobioelectrochemistry. In order to optimise the interaction between electrode and redox protein, either the electrode or the protein can be engineered, with the former being the most adopted approach. This tutorial review provides a basic description of the most commonly used electrode materials in bioelectrochemistry and discusses approaches to modify these surfaces. Carbon, gold and transparent electrodes (e.g. indium tin oxide) are covered, while approaches to form meso- and macroporous structured electrodes are also described. Electrode modifications include the chemical modification with (self-assembled) monolayers and the use of conducting polymers in which the protein is imbedded. The proteins themselves can either be in solution, electrostatically adsorbed on the surface or covalently bound to the electrode. Drawbacks and benefits of each material and its modifications are discussed. Where examples exist of applications in photobioelectrochemistry, these are highlighted.

The role of modifications in codon discrimination by tRNA(Lys)UUU.

PubMed

Murphy, Frank V; Ramakrishnan, Venki; Malkiewicz, Andrzej; Agris, Paul F

2004-12-01

The natural modification of specific nucleosides in many tRNAs is essential during decoding of mRNA by the ribosome. For example, tRNA(Lys)(UUU) requires the modification N6-threonylcarbamoyladenosine at position 37 (t(6)A37), adjacent and 3' to the anticodon, to bind AAA in the A site of the ribosomal 30S subunit. Moreover, it can only bind both AAA and AAG lysine codons when doubly modified with t(6)A37 and either 5-methylaminomethyluridine or 2-thiouridine at the wobble position (mnm(5)U34 or s(2)U34). Here we report crystal structures of modified tRNA anticodon stem-loops bound to the 30S ribosomal subunit with lysine codons in the A site. These structures allow the rationalization of how modifications in the anticodon loop enable decoding of both lysine codons AAA and AAG.

Covalent modification of graphene and graphite using diazonium chemistry: tunable grafting and nanomanipulation.

PubMed

Greenwood, John; Phan, Thanh Hai; Fujita, Yasuhiko; Li, Zhi; Ivasenko, Oleksandr; Vanderlinden, Willem; Van Gorp, Hans; Frederickx, Wout; Lu, Gang; Tahara, Kazukuni; Tobe, Yoshito; Uji-I, Hiroshi; Mertens, Stijn F L; De Feyter, Steven

2015-05-26

We shine light on the covalent modification of graphite and graphene substrates using diazonium chemistry under ambient conditions. We report on the nature of the chemical modification of these graphitic substrates, the relation between molecular structure and film morphology, and the impact of the covalent modification on the properties of the substrates, as revealed by local microscopy and spectroscopy techniques and electrochemistry. By careful selection of the reagents and optimizing reaction conditions, a high density of covalently grafted molecules is obtained, a result that is demonstrated in an unprecedented way by scanning tunneling microscopy (STM) under ambient conditions. With nanomanipulation, i.e., nanoshaving using STM, surface structuring and functionalization at the nanoscale is achieved. This manipulation leads to the removal of the covalently anchored molecules, regenerating pristine sp(2) hybridized graphene or graphite patches, as proven by space-resolved Raman microscopy and molecular self-assembly studies.

Qualitative analysis of student beliefs and attitudes after an objective structured clinical evaluation: implications for affective domain learning in undergraduate nursing education.

PubMed

Cazzell, Mary; Rodriguez, Amber

2011-12-01

This qualitative study explored the feelings, beliefs, and attitudes of senior-level undergraduate pediatric nursing students upon completion of a medication administration Objective Structured Clinical Evaluation (OSCE). The affective domain is the most neglected domain in higher education, although it is deemed the "gateway to learning." Quantitative assessments of clinical skills performed during OSCEs usually address two of the three domains of learning: cognitive (knowledge) and psychomotor skills. Twenty students volunteered to participate in focus groups (10 per group) and were asked three questions relevant to their feelings, beliefs, and attitudes about their OSCE experiences. Students integrated the attitude of safety first into future practice but felt that anxiety, loss of control, reaction under pressure, and no feedback affected their ability to connect the OSCE performance with future clinical practice. The findings affect future affective domain considerations in the development, modification, and assessment of OSCEs across the undergraduate nursing curriculum.

Assessing Hand Muscle Structural Modifications in Chronic Stroke.

PubMed

Zong, Ya; Shin, Henry H; Wang, Ying-Chih; Li, Sheng; Zhou, Ping; Li, Xiaoyan

2018-01-01

The purpose of the study is to assess poststroke muscle structural alterations by examining muscular electrical conductivity and inherent electrophysiological properties. In particular, muscle impedance and compound muscle action potentials (CMAP) were measured from the hypothenar muscle bilaterally using the electrical impedance myography and the electrophysiological techniques, respectively. Significant changes of muscle impedance were observed in the paretic muscle compared with the contralateral side (resistance: paretic: 27.54 ± 0.97 Ω, contralateral: 25.46 ± 0.91 Ω, p  < 0.05; phase angle: paretic: 8.81 ± 0.61°, contralateral: 10.79 ± 0.69°, p  < 0.05). In addition, impedance changes correlated moderately with the CMAP amplitude in the paretic hand (phase angle: r  = 0.66, p  < 0.05; reactance: r  = 0.58, p  < 0.05). The study discloses significant muscle rearrangements as a result of fiber loss or atrophy, fat infiltration or impaired membrane integrity in chronic stroke.

Monotopic modifications derived from in vitro glycation of albumin with ribose.

PubMed

Pataridis, Statis; Stastná, Zdeňka; Sedláková, Pavla; Mikšík, Ivan

2013-06-01

Post-translational modifications are significant reactions that occur to proteins. One of these modifications is a non-enzymatic reaction between the oxo-group(s) of sugars and amino-group(s) of protein - glycation. This reaction plays an important role in the chronic complications of diabetes mellitus, or in the aging process of organisms, that is, it has an important role in the pathophysiology and "normal" physiology of animals. In the work presented here, we studied the glycation of albumins (HSA and BSA). Methodologically, we used nano-LC coupled to a QTOF mass spectrometer. In vitro-modified proteins were cleaved by trypsin and the arising peptides were separated on a C(18) nano column with a trap-column. Peptides and their modifications were analysed with a high-resolution QTOF mass spectrometer with a mass determination precision of better than 5 ppm. Non-enzymatic in vitro reaction products between albumin and ribose were identified. Besides well-known carboxymethyl lysine, new modifications were determined - creating mass shifts of 78 and 218. The origin of the first modification is discussed and its possible structure is presented. In addition, a mass shift of 132 belonging to a Schiff base was also identified. The location of all the modifications within the structure of the proteins was determined and their reactivity to various oxo-compounds was also examined. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structual Effects of Cytidine 2^' Ribose Modifications as Determined by Irmpd Action Spectroscopy

NASA Astrophysics Data System (ADS)

Hamlow, Lucas; He, Chenchen; Fan, Lin; Wu, Ranran; Yang, Bo; Rodgers, M. T.; Berden, Giel; Oomens, J.

2015-06-01

Modified nucleosides, both naturally occurring and synthetic play an important role in understanding and manipulating RNA and DNA. Naturally occurring modified nucleosides are commonly found in functionally important regions of RNA and also affect antibiotic resistance or sensitivity. Synthetic modifications of nucleosides such as fluorinated and arabinosyl nucleosides have found uses as anti-virals and chemotherapy agents. Understanding the effect that modifications have on structure and glycosidic bond stability may lend insight into the functions of these modified nucleosides. Modifications such as the naturally occurring 2^'-O-methylation and the synthetic 2^'-fluorination are believed to help stabilize the nucleoside through the glycosidic bond stability and intramolecular hydrogen bonding. Changing the sugar from ribose to arabinose alters the stereochemistry at the 2^' position and thus shifts the 3D orientation of the 2^'-hydroxyl group, which also affects intramolecular hydrogen bonding and glycosidic bond stability. The structures of 2^'-deoxy-2^'-fluorocytidine, 2^'-O-methylcytidine and cytosine arabinoside are examined in the current work by measuring the infrared spectra in the IR fingerprint region using infrared multiple photon dissociation (IRMPD) action spectroscopy. The structures accessed in the experiments were determined via comparison of the measured IRMPD action spectra to the theoretical linear IR spectra determined by density functional theory and molecular modeling for the stable low-energy structures. Although glycosidic bond stability cannot be quantitatively determined from this data, complementary TCID studies will establish the effect of these modifications. Comparison of these modified nucleosides with their RNA and DNA analogues will help elucidate differences in their intrinsic chemistry.

Structural analyses for the modification and verification of the Viking aeroshell

NASA Technical Reports Server (NTRS)

Stephens, W. B.; Anderson, M. S.

1976-01-01

The Viking aeroshell is an extremely lightweight flexible shell structure that has undergone thorough buckling analyses in the course of its development. The analytical tools and modeling technique required to reveal the structural behavior are presented. Significant results are given which illustrate the complex failure modes not usually observed in simple models and analyses. Both shell-of-revolution analysis for the pressure loads and thermal loads during entry and a general shell analysis for concentrated tank loads during launch were used. In many cases fixes or alterations to the structure were required, and the role of the analytical results in determining these modifications is indicated.

Real-time in situ study of femtosecond-laser-induced periodic structures on metals by linear and nonlinear optics.

PubMed

Zhang, Jihua; He, Yizhuo; Lam, Billy; Guo, Chunlei

2017-08-21

Femtosecond-laser surface structuring on metals is investigated in real time by both fundamental and second harmonic generation (SHG) signals. The onset of surface modification and its progress can be monitored by both the fundamental and SHG probes. However, the dynamics of femtosecond-laser-induced periodic surface structures (FLIPSSs) formation can only be revealed by SHG but not fundamental because of the higher sensitivity of SHG to structural geometry on metal. Our technique provides a simple and effective way to monitor the surface modification and FLIPSS formation thresholds and allows us to obtain the optimal FLIPSS for SHG enhancement.

Inhibitors of enzymes catalyzing modifications to histone lysine residues: structure, function and activity.

PubMed

Lillico, Ryan; Stesco, Nicholas; Khorshid Amhad, Tina; Cortes, Claudia; Namaka, Mike P; Lakowski, Ted M

2016-05-01

Gene expression is partly controlled by epigenetic mechanisms including histone-modifying enzymes. Some diseases are caused by changes in gene expression that can be mitigated by inhibiting histone-modifying enzymes. This review covers the enzyme inhibitors targeting histone lysine modifications. We summarize the enzymatic mechanisms of histone lysine acetylation, deacetylation, methylation and demethylation and discuss the biochemical roles of these modifications in gene expression and in disease. We discuss inhibitors of lysine acetylation, deacetylation, methylation and demethylation defining their structure-activity relationships and their potential mechanisms. We show that there are potentially indiscriminant off-target effects on gene expression even with the use of selective epigenetic enzyme inhibitors.

Structures of ribonucleoprotein particle modification enzymes

PubMed Central

Liang, Bo; Li, Hong

2016-01-01

Small nucleolar and Cajal body ribonucleoprotein particles (RNPs) are required for the maturation of ribosomes and spliceosomes. They consist of small nucleolar RNA or Cajal body RNA combined with partner proteins and represent the most complex RNA modification enzymes. Recent advances in structure and function studies have revealed detailed information regarding ribonucleoprotein assembly and substrate binding. These enzymes form intertwined RNA–protein assemblies that facilitate reversible binding of the large ribosomal RNA or small nuclear RNA. These revelations explain the specificity among the components in enzyme assembly and substrate modification. The multiple conformations of individual components and those of complete RNPs suggest a dynamic assembly process and justify the requirement of many assembly factors in vivo. PMID:21108865

Crash Modification Factors Needs Assessment Workshop

DOT National Transportation Integrated Search

2015-03-01

The Federal Highway Administration (FHWA) hosted a Crash Modification Factor (CMF) Stakeholder Meeting to provide a forum for CMF stakeholders to communicate ongoing efforts and identify opportunities for future collaboration. CMF stakeholders repres...

Characterization of a PEGylated protein therapeutic by ion exchange chromatography with on-line detection by native ESI MS and MS/MS.

PubMed

Muneeruddin, K; Bobst, C E; Frenkel, R; Houde, D; Turyan, I; Sosic, Z; Kaltashov, I A

2017-01-16

Detailed profiling of both enzymatic (e.g., glycosylation) and non-enzymatic (e.g., oxidation and deamidation) post-translational modifications (PTMs) is frequently required for the quality assessment of protein-based drugs. Challenging as it is, this task is further complicated for the so-called second-generation biopharmaceuticals, which also contain "designer PTMs" introduced to either enhance their pharmacokinetic profiles (e.g., PEGylated proteins) or endow them with therapeutic activity (e.g., protein-drug conjugates). Such modifications of protein covalent structure can dramatically increase structural heterogeneity, making the very notion of "molecular mass" meaningless, as ions representing different glycoforms of a PEGylated protein may have nearly identical distributions of ionic current as a function of m/z, making their contributions to the mass spectrum impossible to distinguish. In this work we demonstrate that a combination of ion exchange chromatography (IXC) with on-line detection by electrospray ionization mass spectrometry (ESI MS) and methods of ion manipulation in the gas phase (limited charge reduction and collision-induced dissociation) allows meaningful structural information to be obtained on a structurally heterogeneous sample of PEGylated interferon β-1a. IXC profiling of the protein sample gives rise to a convoluted chromatogram with several partially resolved peaks which can represent both deamidation and different glycosylation patterns within the protein, as well as varying extent of PEGylation. Thus, profiling the protein with on-line IXC/ESI/MS/MS allows it to be characterized by providing information on three different types of PTMs (designer, enzymatic and non-enzymatic) within a single protein therapeutic.

[Improvement in quality of life and exercise capacity without muscular biology changes after general training in patients with severe chronic obstructive pulmonary disease].

PubMed

Pascual-Guardia, Sergio; Wodja, Emil; Gorostiza, Amaya; López de Santamaría, Elena; Gea, Joaquim; Gáldiz, Juan B; Sliwinski, Pawel; Barreiro, Esther

2013-03-02

Despite the beneficial effects of exercise training in chronic obstructive pulmonary disease (COPD) patients, several studies have revealed functional and biological abnormalities in their peripheral muscles. The objective was to determine whether exercise training of high intensity and long duration modifies oxidative stress levels and structure of respiratory and peripheral muscles of severe COPD patients, while also improving their exercise capacity and quality of life. Multicenter study (Warsaw and Barakaldo) in which 25 severe COPD out-patients were recruited from the COPD clinics. In all patients, lung and muscle functions, exercise capacity (walking test and cycloergometer) and quality of life (QoL) were assessed, and open muscle biopsies from the vastus lateralis and external intercostals (n=14) were obtained before and after an exercise training program of high intensity (respiratory rehabilitation area, 70% maximal tolerated load in a cycloergometer) and long duration (10 weeks). Oxidative stress and muscle structural modifications were evaluated in all muscle biopsies using immunoblotting and immunohistochemistry. In all patients, after the training program, without any drop-outs, exercise capacity and QoL improved significantly, whereas oxidative stress, muscle damage and structure were not modified in their respiratory or limb muscles compared to baseline. In patients with severe COPD, exercise training of high intensity and long duration significantly improves their exercise capacity and QoL, without inducing significant modifications on oxidative stress levels or muscle structure in their respiratory or peripheral muscles. These results may have future clinical therapeutic implications. Copyright © 2011 Elsevier España, S.L. All rights reserved.

Utilization of two web-based continuing education courses evaluated by Markov chain model.

PubMed

Tian, Hao; Lin, Jin-Mann S; Reeves, William C

2012-01-01

To evaluate the web structure of two web-based continuing education courses, identify problems and assess the effects of web site modifications. Markov chain models were built from 2008 web usage data to evaluate the courses' web structure and navigation patterns. The web site was then modified to resolve identified design issues and the improvement in user activity over the subsequent 12 months was quantitatively evaluated. Web navigation paths were collected between 2008 and 2010. The probability of navigating from one web page to another was analyzed. The continuing education courses' sequential structure design was clearly reflected in the resulting actual web usage models, and none of the skip transitions provided was heavily used. The web navigation patterns of the two different continuing education courses were similar. Two possible design flaws were identified and fixed in only one of the two courses. Over the following 12 months, the drop-out rate in the modified course significantly decreased from 41% to 35%, but remained unchanged in the unmodified course. The web improvement effects were further verified via a second-order Markov chain model. The results imply that differences in web content have less impact than web structure design on how learners navigate through continuing education courses. Evaluation of user navigation can help identify web design flaws and guide modifications. This study showed that Markov chain models provide a valuable tool to evaluate web-based education courses. Both the results and techniques in this study would be very useful for public health education and research specialists.

Utilization of two web-based continuing education courses evaluated by Markov chain model

PubMed Central

Lin, Jin-Mann S; Reeves, William C

2011-01-01

Objectives To evaluate the web structure of two web-based continuing education courses, identify problems and assess the effects of web site modifications. Design Markov chain models were built from 2008 web usage data to evaluate the courses' web structure and navigation patterns. The web site was then modified to resolve identified design issues and the improvement in user activity over the subsequent 12 months was quantitatively evaluated. Measurements Web navigation paths were collected between 2008 and 2010. The probability of navigating from one web page to another was analyzed. Results The continuing education courses' sequential structure design was clearly reflected in the resulting actual web usage models, and none of the skip transitions provided was heavily used. The web navigation patterns of the two different continuing education courses were similar. Two possible design flaws were identified and fixed in only one of the two courses. Over the following 12 months, the drop-out rate in the modified course significantly decreased from 41% to 35%, but remained unchanged in the unmodified course. The web improvement effects were further verified via a second-order Markov chain model. Conclusions The results imply that differences in web content have less impact than web structure design on how learners navigate through continuing education courses. Evaluation of user navigation can help identify web design flaws and guide modifications. This study showed that Markov chain models provide a valuable tool to evaluate web-based education courses. Both the results and techniques in this study would be very useful for public health education and research specialists. PMID:21976027

Aircraft Modifications: Assessing the Current State of Air Force Aircraft Modifications and the Implications for Future Military Capability

DTIC Science & Technology

2007-01-25

Air, Space , and Cyberspace." Introduction 3 group production lots together into ’spirals’ or ’increments’. These groupings, as well as an increased...important reference point for this work. The analysis of the modification process presented in this reserach , however, does help shed light on the...planning efforts. Chapter 7- The Future of Aircraft Modifications "Strategy is the art of making use of time and space . I am less concerned about the

Synthesis, structural studies and biological properties of new TBA analogues containing an acyclic nucleotide.

PubMed

Coppola, Teresa; Varra, Michela; Oliviero, Giorgia; Galeone, Aldo; D'Isa, Giuliana; Mayol, Luciano; Morelli, Elena; Bucci, Maria-Rosaria; Vellecco, Valentina; Cirino, Giuseppe; Borbone, Nicola

2008-09-01

A new modified acyclic nucleoside, namely N(1)-(3-hydroxy-2-hydroxymethyl-2-methylpropyl)-thymidine, was synthesized and transformed into a building block useful for oligonucleotide (ON) automated synthesis. A series of modified thrombin binding aptamers (TBAs) in which the new acyclic nucleoside replaces, one at the time, the thymidine residues were then synthesized and characterized by UV, CD, MS, and (1)H NMR. The biological activity of the resulting TBAs was tested by Prothrombin Time assay (PT assay) and by purified fibrinogen clotting assay. From a structural point of view, nearly all the new TBA analogues show a similar behavior as the unmodified counterpart, being able to fold into a bimolecular or monomolecular quadruplex structure depending on the nature of monovalent cations (sodium or potassium) coordinated in the quadruplex core. From the comparison of structural and biological data, some important structure-activity relationships emerged, particularly when the modification involved the TT loops. In agreement with previous studies we found that the folding ability of TBA analogues is more affected by modifications involving positions 4 and 13, rather than positions 3 and 12. On the other hand, the highest anti-thrombin activities were detected for aptamers containing the modification at T13 or T12 positions, thus indicating that the effects produced by the introduction of the acyclic nucleoside on the biological activity are not tightly connected with structure stabilities. It is noteworthy that the modification at T7 produces an ON being more stable and active than the natural TBA.

Structural and morphological modifications of polymer thin film in the presence of nonsolvent

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

Talukdar, Hrishikesh, E-mail: hiasst@yahoo.in; Kundu, Sarathi

Thin films of sodium poly(acrylic acid) salt (Na-PAA) have been investigated to obtain the modification of the out-of-plane structure and surface morphology in the presence of toluene which is considered as nonsolvent for Na-PAA. X-ray reflectivity analysis show that the out-of-plane thickness of the Na-PAA film increases if the film is kept for longer time inside the toluene. For the thicker film the effect of toluene is more pronounced than the thinner one. Surface morphology obtained from the atomic force microscopy shows that the top surface becomes relatively rough after the dipping of the Na-PAA film inside toluene. Although toluenemore » is nonsolvent for Na-PAA molecules, however, the effect of restructuring of the nanometer-thick polymer film cannot be ignored. The reason for such structural modification has been proposed.« less

Analysis and modification of defective surface aggregates on PCDTBT:PCBM solar cell blends using combined Kelvin probe, conductive and bimodal atomic force microscopy

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

Noh, Hanaul; Diaz, Alfredo J.; Solares, Santiago D.

Organic photovoltaic systems comprising donor polymers and acceptor fullerene derivatives are attractive for inexpensive energy harvesting. Extensive research on polymer solar cells has provided insight into the factors governing device-level efficiency and stability. However, the detailed investigation of nanoscale structures is still challenging. Here we demonstrate the analysis and modification of unidentified surface aggregates. The aggregates are characterized electrically by Kelvin probe force microscopy and conductive atomic force microscopy (C-AFM), whereby the correlation between local electrical potential and current confirms a defective charge transport. Bimodal AFM modification confirms that the aggregates exist on top of the solar cell structure, andmore » is used to remove them and to reveal the underlying active layer. The systematic analysis of the surface aggregates suggests that the structure consists of PCBM molecules.« less

Analysis and modification of defective surface aggregates on PCDTBT:PCBM solar cell blends using combined Kelvin probe, conductive and bimodal atomic force microscopy

DOE PAGES

Noh, Hanaul; Diaz, Alfredo J.; Solares, Santiago D.

2017-03-08

Organic photovoltaic systems comprising donor polymers and acceptor fullerene derivatives are attractive for inexpensive energy harvesting. Extensive research on polymer solar cells has provided insight into the factors governing device-level efficiency and stability. However, the detailed investigation of nanoscale structures is still challenging. Here we demonstrate the analysis and modification of unidentified surface aggregates. The aggregates are characterized electrically by Kelvin probe force microscopy and conductive atomic force microscopy (C-AFM), whereby the correlation between local electrical potential and current confirms a defective charge transport. Bimodal AFM modification confirms that the aggregates exist on top of the solar cell structure, andmore » is used to remove them and to reveal the underlying active layer. The systematic analysis of the surface aggregates suggests that the structure consists of PCBM molecules.« less

In Vivo Multiparametric Ultrasound Imaging of Structural and Functional Tumor Modifications during Therapy.

PubMed

Dizeux, Alexandre; Payen, Thomas; Le Guillou-Buffello, Delphine; Comperat, Eva; Gennisson, Jean-Luc; Tanter, Mickael; Oelze, Michael; Bridal, S Lori

2017-09-01

Longitudinal imaging techniques are needed that can meaningfully probe the tumor microenvironment and its spatial heterogeneity. Contrast-enhanced ultrasound, shear wave elastography and quantitative ultrasound are ultrasound-based techniques that provide information on the vascular function and micro-/macroscopic tissue structure. Modifications of the tumor microenvironment induced by cytotoxic and anti-angiogenic molecules in ectopic murine Lewis lung carcinoma tumors were monitored. The most heterogenous structures were found in tumors treated with anti-angiogenic drug that simultaneously accumulated the highest levels of necrosis and fibrosis. The anti-angiogenic group presented the highest number of correlations between parameters related to vascular function and those related to the micro-/macrostructure of the tumor microenvironment. Results suggest how patterns of multiparametric ultrasound modifications can be related to provide a more insightful marker of changes occurring within tumors during therapy. Copyright © 2017. Published by Elsevier Inc.

Structuring of material parameters in lithium niobate crystals with low-mass, high-energy ion radiation

NASA Astrophysics Data System (ADS)

Peithmann, K.; Eversheim, P.-D.; Goetze, J.; Haaks, M.; Hattermann, H.; Haubrich, S.; Hinterberger, F.; Jentjens, L.; Mader, W.; Raeth, N. L.; Schmid, H.; Zamani-Meymian, M.-R.; Maier, K.

2011-10-01

Ferroelectric lithium niobate crystals offer a great potential for applications in modern optics. To provide powerful optical components, tailoring of key material parameters, especially of the refractive index n and the ferroelectric domain landscape, is required. Irradiation of lithium niobate crystals with accelerated ions causes strong structured modifications in the material. The effects induced by low-mass, high-energy ions (such as 3He with 41 MeV, which are not implanted, but transmit through the entire crystal volume) are reviewed. Irradiation yields large changes of the refractive index Δn, improved domain engineering capability within the material along the ion track, and waveguiding structures. The periodic modification of Δn as well as the formation of periodically poled lithium niobate (PPLN) (supported by radiation damage) is described. Two-step knock-on displacement processes, 3He→Nb and 3He→O causing thermal spikes, are identified as origin for the material modifications.

Analysis and modification of defective surface aggregates on PCDTBT:PCBM solar cell blends using combined Kelvin probe, conductive and bimodal atomic force microscopy

PubMed Central

Noh, Hanaul; Diaz, Alfredo J

2017-01-01

Organic photovoltaic systems comprising donor polymers and acceptor fullerene derivatives are attractive for inexpensive energy harvesting. Extensive research on polymer solar cells has provided insight into the factors governing device-level efficiency and stability. However, the detailed investigation of nanoscale structures is still challenging. Here we demonstrate the analysis and modification of unidentified surface aggregates. The aggregates are characterized electrically by Kelvin probe force microscopy and conductive atomic force microscopy (C-AFM), whereby the correlation between local electrical potential and current confirms a defective charge transport. Bimodal AFM modification confirms that the aggregates exist on top of the solar cell structure, and is used to remove them and to reveal the underlying active layer. The systematic analysis of the surface aggregates suggests that the structure consists of PCBM molecules. PMID:28382247

View of Soviet ionospheric modification research

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

Duncan, L.M.; Showen, R.L.

1990-10-01

We have reviewed and provided a technical assessment of Soviet research of the past five to ten years in ionospheric modification by high-power radio waves. This review includes a comprehensive survey of Soviet published literature, conference proceedings, and direct discussions with the involved Soviet researchers. The current state of the art for Soviet research in this field is evaluated, identifying areas of potential breakthrough discoveries, and discussing implications of this work for emerging technologies and future applications. This assessment is divided into the categories of basic research, advanced research, and applications. Basic research is further subdivided into studies of themore » modified natural geophysical environment, nonlinear plasma physics, and polar geophysical studies. Advanced research topics include the generation of artificial ionization mirrors and high-power oblique propagation effects. A separate comparative assessment of Soviet theoretical work also is included in this analysis. Our evaluation of practical and potential applications of this research discusses the utility of ionospheric modification in creating disturbed radio wave propagation environments, and its role in current and future remote-sensing and telecommunications systems. This technical assessment does not include consideration of ionospheric modification by means other than high-power radio waves. The Soviet effort in ionospheric modification sustains theoretical and experimental research at activity levels considerably greater than that found in comparable programs in the West. Notable strengths of the Soviet program are its breadth of coverage, large numbers of scientific participation, theoretical creativity and insight, and its powerful radio wave transmitting facilities.« less

Bis(dipyridophenazine)(2-(2'-pyridyl)pyrimidine-4-carboxylic acid)ruthenium(II) hexafluorophosphate: a lesson in stubbornness.

PubMed

Joshi, Tanmaya; Pierroz, Vanessa; Ferrari, Stefano; Gasser, Gilles

2014-07-01

Ruthenium complexes are currently considered to be among the most promising alternatives to platinum anticancer drugs. In this work, thirteen structural analogues and organelle/receptor-targeting peptide bioconjugates of a cytotoxic bis(dppz)-Ru(II) complex [Ru(dppz)2 (CppH)](PF6 )2 (1) were prepared, characterized, and assessed for their cytotoxicity and cellular localization (CppH=2-(2'-pyridyl)pyrimidine-4-carboxylic acid; dppz=dipyrido[3,2-a:2',3'-c]phenazine). It was observed that structural modifications (lipophilicity, charge, and size-based) result in the cytotoxic potency of 1 being compromised. Confocal microscopy studies revealed that unlike 1, the screened complexes/bioconjugates do not have a preferential accumulation in mitochondria. The results of this important structure-activity relationship strongly support our initial hypothesis that accumulation in mitochondria is crucial for 1 to exert its cytotoxic action. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the assessments of arabinoxylan localization and enzymatic modifications for enhanced protein networking and its structural impact on rye dough and bread.

PubMed

Döring, Clemens; Hussein, Mohamed A; Jekle, Mario; Becker, Thomas

2017-08-15

For rye dough structure, it is hypothesised that the presence of arabinoxylan hinders the proteins from forming a coherent network. This hypothesis was investigated using fluorescent-stained antibodies that bind to the arabinoxylan chains. Image analysis proves that the arabinoxylan surrounds the proteins, negatively affecting protein networking. Further, it is hypothesised that the dosing of xylanase and transglutaminase has a positive impact on rye dough and bread characteristics; the findings in this study evidenced that this increases the protein network by up to 38% accompanied by a higher volume rise of 10.67%, compared to standard rye dough. These outcomes combine a product-oriented and physiochemical design of a recipe, targeting structural and functional relationships, and demonstrate a successful methodology for enhancing rye bread quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

Experimental study of turbulent structures over hairy poro-elastic surfaces

NASA Astrophysics Data System (ADS)

Couliou, Marie; Hansson, Jonas; van der Wijngaart, Wouter; Lundell, Fredrik; Bagheri, Shervin

2016-11-01

Flows over slender, deformable and dense structures are ubiquitous in both nature and technological applications, ranging from the atmospheric flow over trees to the flow over the over the skin of organisms. In order to create a fundamental understanding of how poro-elatic surface can be used for flow control purposes, our work focuses on the behaviour of wall-bounded turbulent flows over fibrous poro-elastic surfaces. We fabricate the coatings using Off-Stoichiometry-Thiolene-Epoxy (OSTE+) polymers and multidirectional UV-lithography which enables us to design arrays of flexible pillars with various geometrical parameters (aspect ratio, pitch, inclinaison, etc.). We assess the effects of these coatings on an overlying low-Reynolds number turbulent flow using a water-table facility and PIV measurements. In particular, we focus on the modification of near wall turbulent structures in both space and time due to the presence of the poro-elastic coatings.

Phosphomimics destabilize Hsp27 oligomeric assemblies and enhance chaperone activity.

PubMed

Jovcevski, Blagojce; Kelly, Megan A; Rote, Anthea P; Berg, Tracey; Gastall, Heidi Y; Benesch, Justin L P; Aquilina, J Andrew; Ecroyd, Heath

2015-02-19

Serine phosphorylation of the mammalian small heat-shock protein Hsp27 at residues 15, 78, and 82 is thought to regulate its structure and chaperone function; however, the site-specific impact has not been established. We used mass spectrometry to assess the combinatorial effect of mutations that mimic phosphorylation upon the oligomeric state of Hsp27. Comprehensive dimerization yielded a relatively uncrowded spectrum, composed solely of even-sized oligomers. Modification at one or two serines decreased the average oligomeric size, while the triple mutant was predominantly a dimer. These changes were reflected in a greater propensity for oligomers to dissociate upon increased modification. The ability of Hsp27 to prevent amorphous or fibrillar aggregation of target proteins was enhanced and correlated with the amount of dissociated species present. We propose that, in vivo, phosphorylation promotes oligomer dissociation, thereby enhancing chaperone activity. Our data support a model in which dimers are the chaperone-active component of Hsp27. Copyright © 2015 Elsevier Ltd. All rights reserved.

CRISPR-Mediated Epigenome Editing

PubMed Central

Enríquez, Paul

2016-01-01

Mounting evidence has called into question our understanding of the role that the central dogma of molecular biology plays in human pathology. The conventional view that elucidating the mechanisms for translating genes into proteins can account for a panoply of diseases has proven incomplete. Landmark studies point to epigenetics as a missing piece of the puzzle. However, technological limitations have hindered the study of specific roles for histone post-translational modifications, DNA modifications, and non-coding RNAs in regulation of the epigenome and chromatin structure. This feature highlights CRISPR systems, including CRISPR-Cas9, as novel tools for targeted epigenome editing. It summarizes recent developments in the field, including integration of optogenetic and functional genomic approaches to explore new therapeutic opportunities, and underscores the importance of mitigating current limitations in the field. This comprehensive, analytical assessment identifies current research gaps, forecasts future research opportunities, and argues that as epigenome editing technologies mature, overcoming critical challenges in delivery, specificity, and fidelity should clear the path to bring these technologies into the clinic. PMID:28018139

How many human proteoforms are there?

PubMed

Aebersold, Ruedi; Agar, Jeffrey N; Amster, I Jonathan; Baker, Mark S; Bertozzi, Carolyn R; Boja, Emily S; Costello, Catherine E; Cravatt, Benjamin F; Fenselau, Catherine; Garcia, Benjamin A; Ge, Ying; Gunawardena, Jeremy; Hendrickson, Ronald C; Hergenrother, Paul J; Huber, Christian G; Ivanov, Alexander R; Jensen, Ole N; Jewett, Michael C; Kelleher, Neil L; Kiessling, Laura L; Krogan, Nevan J; Larsen, Martin R; Loo, Joseph A; Ogorzalek Loo, Rachel R; Lundberg, Emma; MacCoss, Michael J; Mallick, Parag; Mootha, Vamsi K; Mrksich, Milan; Muir, Tom W; Patrie, Steven M; Pesavento, James J; Pitteri, Sharon J; Rodriguez, Henry; Saghatelian, Alan; Sandoval, Wendy; Schlüter, Hartmut; Sechi, Salvatore; Slavoff, Sarah A; Smith, Lloyd M; Snyder, Michael P; Thomas, Paul M; Uhlén, Mathias; Van Eyk, Jennifer E; Vidal, Marc; Walt, David R; White, Forest M; Williams, Evan R; Wohlschlager, Therese; Wysocki, Vicki H; Yates, Nathan A; Young, Nicolas L; Zhang, Bing

2018-02-14

Despite decades of accumulated knowledge about proteins and their post-translational modifications (PTMs), numerous questions remain regarding their molecular composition and biological function. One of the most fundamental queries is the extent to which the combinations of DNA-, RNA- and PTM-level variations explode the complexity of the human proteome. Here, we outline what we know from current databases and measurement strategies including mass spectrometry-based proteomics. In doing so, we examine prevailing notions about the number of modifications displayed on human proteins and how they combine to generate the protein diversity underlying health and disease. We frame central issues regarding determination of protein-level variation and PTMs, including some paradoxes present in the field today. We use this framework to assess existing data and to ask the question, "How many distinct primary structures of proteins (proteoforms) are created from the 20,300 human genes?" We also explore prospects for improving measurements to better regularize protein-level biology and efficiently associate PTMs to function and phenotype.

CRISPR-Mediated Epigenome Editing.

PubMed

Enríquez, Paul

2016-12-01

Mounting evidence has called into question our understanding of the role that the central dogma of molecular biology plays in human pathology. The conventional view that elucidating the mechanisms for translating genes into proteins can account for a panoply of diseases has proven incomplete. Landmark studies point to epigenetics as a missing piece of the puzzle. However, technological limitations have hindered the study of specific roles for histone post-translational modifications, DNA modifications, and non-coding RNAs in regulation of the epigenome and chromatin structure. This feature highlights CRISPR systems, including CRISPR-Cas9, as novel tools for targeted epigenome editing. It summarizes recent developments in the field, including integration of optogenetic and functional genomic approaches to explore new therapeutic opportunities, and underscores the importance of mitigating current limitations in the field. This comprehensive, analytical assessment identifies current research gaps, forecasts future research opportunities, and argues that as epigenome editing technologies mature, overcoming critical challenges in delivery, specificity, and fidelity should clear the path to bring these technologies into the clinic.

An in vitro bacterial adhesion assessment of surface-modified medical-grade PVC.

PubMed

Asadinezhad, Ahmad; Novák, Igor; Lehocký, Marián; Sedlarík, Vladimir; Vesel, Alenka; Junkar, Ita; Sáha, Petr; Chodák, Ivan

2010-06-01

Medical-grade polyvinyl chloride was surface modified by a multistep physicochemical approach to improve bacterial adhesion prevention properties. This was fulfilled via surface activation by diffuse coplanar surface barrier discharge plasma followed by radical graft copolymerization of acrylic acid through surface-initiated pathway to render a structured high density brush. Three known antibacterial agents, bronopol, benzalkonium chloride, and chlorhexidine, were then individually coated onto functionalized surface to induce biological properties. Various modern surface probe techniques were employed to explore the effects of the modification steps. In vitro bacterial adhesion and biofilm formation assay was performed. Escherichia coli strain was found to be more susceptible to modifications rather than Staphylococcus aureus as up to 85% reduction in adherence degree of the former was observed upon treating with above antibacterial agents, while only chlorhexidine could retard the adhesion of the latter by 50%. Also, plasma treated and graft copolymerized samples were remarkably effective to diminish the adherence of E. coli. Copyright 2010 Elsevier B.V. All rights reserved.

Immobilized copper(II) macrocyclic complex on MWCNTs with antibacterial activity

NASA Astrophysics Data System (ADS)

Tarlani, Aliakbar; Narimani, Khashayar; Mohammadipanah, Fatemeh; Hamedi, Javad; Tahermansouri, Hasan; Amini, Mostafa M.

2015-06-01

In a new approach, a copper(II) tetraaza macrocyclic complex (CuTAM) was covalently bonded on modified multi-walled carbon nanotubes (MWCNTs). To achieve this purpose, MWCNTs were converted to MWCNT-COCl and then reacted to NH groups of TAM ligand. The prepared material was characterized by Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis (TGA), and FESEM (field emission scanning electron microscopy). FT-IR and TGA demonstrated the presence of the organic moieties, and XRD proved that the structure of MWCNTs remained intact during the three modification steps. An increase in the ID/IG ratio in Raman spectra confirmed the surface modifications. Finally, the samples were subjected to an antibacterial assessment to compare their biological activity. The antibacterial test showed that the grafted complex on the surface of the nanotube (MWCNT-CO-CuTAM) has higher antibacterial activity against Bacillus subtilis ATCC 6633 than the MWCNT-COOH and CuTAM with 1000 and 2000 μg/mL.

Aerodynamic Improvements to Cargo Carrying Rail Cars due to Roof Modifications

NASA Astrophysics Data System (ADS)

Condie, Robert; Maynes, Daniel

2012-11-01

The aerodynamic drag associated with the transport of commodities by rail is becoming increasingly important as the cost of diesel fuel increases. We provide an assessment of the influence of the roof structure on aerodynamic performance of two dissimilar rail cars, namely automobile carrying cars and coal carrying cars. Currently, the roof material for automobile carrying rail cars is corrugated steel, with the corrugation aligned perpendicular to the direction of travel. Coal cars are currently left uncovered for loading convenience and on the return leg from the power plant are empty. Aerodynamic drag data have been obtained through wind tunnel testing on 1/29 scale models to understand the savings that may be realized by judicious modification to the tops of both these car types. For the automobile-carrying cars, testing is performed for the corrugated and smooth roof configurations. This modification alone has the potential of reducing the car drag coefficient by nominally 25%. A broader study is performed for the coal cars, with data being acquired for coal filled models, empty models, and several cover prototype configurations. The results reveal that implementation of a cover may yield reductions in the aerodynamic drag for both coal filled (nominally 7%) and empty coal cars (nominally 30%).

Nonenzymatic glycation of guanosine 5'-triphosphate by glyceraldehyde: an in vitro study of AGE formation.

PubMed

Li, Yuyuan; Dutta, Udayan; Cohenford, Menashi A; Dain, Joel A

2007-12-01

Guanosine 5'-triphosphate (GTP) plays a significant role in the bioenergetics, metabolism, and signaling of cells; consequently, any modifications to the structure of the molecule can have profound effects on a cell's survival and function. Previous studies in our laboratory demonstrated that like proteins, purines, and pyrimidines can nonenzymatically react with sugars to generate advanced glycation endproducts (AGEs) and that these AGEs can form in vitro under physiological conditions. The objective of this investigation was twofold. First, it was to evaluate the susceptibility of ATP, GTP, CTP, and TTP to nonenzymatic modification by D-glucose and DL-glyceraldehyde, and second to assess the effect of various factors such as temperature, pH and incubation time, and sugar concentration on the rate and extent of nucleotide triphosphate AGE formation. Of the four nucleotide triphosphates that were studied, only GTP was significantly reactive forming a heterogeneous group of compounds with DL-glyceraldehyde. D-Glucose exhibited no significant reactivity with any of the nucleotide triphosphates, a finding that was supported by UV and fluorescence spectroscopy. Capillary electrophoresis, high-performance liquid chromatography and mass spectrometry allowed for a thorough analysis of the glycated GTP products and demonstrated that the modification of GTP by dl-glyceraldehyde occurred via the classical Amadori pathway.

Flight test operations using an F-106B research airplane modified with a wing leading-edge vortex flap

NASA Technical Reports Server (NTRS)

Dicarlo, Daniel J.; Brown, Philip W.; Hallissy, James B.

1992-01-01

Flight tests of an F-106B aircraft equipped with a leading-edge vortex flap, which represented the culmination of a research effort to examine the effectiveness of the flap, were conducted at the NASA Langley Research Center. The purpose of the flight tests was to establish a data base on the use of a wing leading-edge vortex flap as a means to validate the design and analysis methods associated with the development of such a vortical flow-control concept. The overall experiment included: refinements of the design codes for vortex flaps; numerous wind tunnel entries to aid in verifying design codes and determining basic aerodynamic characteristics; design and fabrication of the flaps, structural modifications to the wing tip and leading edges of the test aircraft; development and installation of an aircraft research instrumentation system, including wing and flap surface pressure measurements and selected structural loads measurements; ground-based simulation to assess flying qualities; and finally, flight testing. This paper reviews the operational aspects associated with the flight experiment, which includes a description of modifications to the research airplane, the overall flight test procedures, and problems encountered. Selected research results are also presented to illustrate the accomplishments of the research effort.

Numerical modelling to assess maintenance strategy management options for a small tidal inlet

NASA Astrophysics Data System (ADS)

Shaeri, Saeed; Tomlinson, Rodger; Etemad-Shahidi, Amir; Strauss, Darrell

2017-03-01

Small tidal inlets are found to be more sensitive to anthropogenic alteration than their larger counterparts. Such alterations, although typically supported by technical design reports, sometimes require amendments or modification. One of the most suitable tools to conduct the necessary studies in this regard is numerical modelling, since the behaviour of the inlet system in response to proposed remedial actions, can easily be identified. In this paper, various alternative proposals are investigated to determine the most practical and viable option to mitigate the need for ongoing maintenance at a typical small, jettied tidal inlet. The main tool to investigate the alternatives is the hydro-sedimentological modelling of the inlet system, which was performed using the Delft3D software package. The proposed alternative entrance modifications were based upon structural alterations of the inlet system (such as a jetty extension or submerged weir) and non-structural scenarios (such as a change of the time of the dredging campaign or the deposition location of the dredged material). It was concluded that whilst a detailed study is inevitable in order to achieve a comprehensive design plan, based upon the results of this study the construction of a submerged weir at the entrance channel can satisfy the needs of most of the stakeholders, with justifiable costs over a longer period.

Performance analyses of helical coil heat exchangers. The effect of external coil surface modification on heat exchanger effectiveness

NASA Astrophysics Data System (ADS)

Andrzejczyk, Rafał; Muszyński, Tomasz

2016-12-01

The shell and coil heat exchangers are commonly used in heating, ventilation, nuclear industry, process plant, heat recovery and air conditioning systems. This type of recuperators benefits from simple construction, the low value of pressure drops and high heat transfer. In helical coil, centrifugal force is acting on the moving fluid due to the curvature of the tube results in the development. It has been long recognized that the heat transfer in the helical tube is much better than in the straight ones because of the occurrence of secondary flow in planes normal to the main flow inside the helical structure. Helical tubes show good performance in heat transfer enhancement, while the uniform curvature of spiral structure is inconvenient in pipe installation in heat exchangers. Authors have presented their own construction of shell and tube heat exchanger with intensified heat transfer. The purpose of this article is to assess the influence of the surface modification over the performance coefficient and effectiveness. The experiments have been performed for the steady-state heat transfer. Experimental data points were gathered for both laminar and turbulent flow, both for co current- and countercurrent flow arrangement. To find optimal heat transfer intensification on the shell-side authors applied the number of transfer units analysis.

NDE1 and NDEL1: twin neurodevelopmental proteins with similar ‘nature’ but different ‘nurture’

PubMed Central

Bradshaw, Nicholas J.; Hennah, William; Soares, Dinesh C.

2013-01-01

Nuclear distribution element 1 (NDE1, also known as NudE) and NDE-like 1 (NDEL1, also known as Nudel) are paralogous proteins essential for mitosis and neurodevelopment that have been implicated in psychiatric and neurodevelopmental disorders. The two proteins possess high sequence similarity and have been shown to physically interact with one another. Numerous lines of experimental evidence in vivo and in cell culture have demonstrated that these proteins share common functions, although instances of differing functions between the two have recently emerged. We review the key aspects of NDE1 and NDEL1 in terms of recent advances in structure elucidation and cellular function, with an emphasis on their differing mechanisms of post-translational modification. Based on a review of the literature and bioinformatics assessment, we advance the concept that the twin proteins NDE1 and NDEL1, while sharing a similar ‘nature’ in terms of their structure and basic functions, appear to be different in their ‘nurture’, the manner in which they are regulated both in terms of expression and of post-translational modification within the cell. These differences are likely to be of significant importance in understanding the specific roles of NDE1 and NDEL1 in neurodevelopment and disease. PMID:24093049

Assessing analytical comparability of biosimilars: GCSF as a case study.

PubMed

Nupur, Neh; Singh, Sumit Kumar; Narula, Gunjan; Rathore, Anurag S

2016-10-01

The biosimilar industry is witnessing an unprecedented growth with the newer therapeutics increasing in complexity over time. A key step towards development of a biosimilar is to establish analytical comparability with the innovator product, which would otherwise affect the safety/efficacy profile of the product. Choosing appropriate analytical tools that can fulfil this objective by qualitatively and/or quantitatively assessing the critical quality attributes (CQAs) of the product is highly critical for establishing equivalence. These CQAs cover the primary and higher order structures of the product, product related variants and impurities, as well as process related impurities, and host cell related impurities. In the present work, we use such an analytical platform for assessing comparability of five approved Granulocyte Colony Stimulating Factor (GCSF) biosimilars (Emgrast, Lupifil, Colstim, Neukine and Grafeel) to the innovator product, Neupogen(®). The comparability studies involve assessing structural homogeneity, identity, secondary structure, and product related modifications. Physicochemical analytical tools include peptide mapping with mass determination, circular dichroism (CD) spectroscopy, reverse phase chromatography (RPC) and size exclusion chromatography (SEC) have been used in this exercise. Bioactivity assessment include comparison of relative potency through in vitro cell proliferation assays. The results from extensive analytical examination offer robust evidence of structural and biological similarity of the products under consideration with the pertinent innovator product. For the most part, the biosimilar drugs were found to be comparable to the innovator drug anomaly that was identified was that three of the biosimilars had a typical variant which was reported as an oxidized species in the literature. But, upon further investigation using RPC-FLD and ESI-MS we found that this is likely a conformational variant of the biotherapeutic been studied. Copyright © 2016 Elsevier B.V. All rights reserved.

Modifications modulate anticodon loop dynamics and codon recognition of E. coli tRNA(Arg1,2).

PubMed

Cantara, William A; Bilbille, Yann; Kim, Jia; Kaiser, Rob; Leszczyńska, Grażyna; Malkiewicz, Andrzej; Agris, Paul F

2012-03-02

Three of six arginine codons are read by two tRNA(Arg) isoacceptors in Escherichia coli. The anticodon stem and loop of these isoacceptors (ASL(Arg1,2)) differs only in that the position 32 cytidine of tRNA(Arg1) is posttranscriptionally modified to 2-thiocytidine (s(2)C(32)). The tRNA(Arg1,2) are also modified at positions 34 (inosine, I(34)) and 37 (2-methyladenosine, m(2)A(37)). To investigate the roles of modifications in the structure and function, we analyzed six ASL(Arg1,2) constructs differing in their array of modifications by spectroscopy and codon binding assays. Thermal denaturation and circular dichroism spectroscopy indicated that modifications contribute thermodynamic and base stacking properties, resulting in more order but less stability. NMR-derived structures of the ASL(Arg1,2) showed that the solution structures of the ASLs were nearly identical. Surprisingly, none possessed the U-turn conformation required for effective codon binding on the ribosome. Yet, all ASL(Arg1,2) constructs efficiently bound the cognate CGU codon. Three ASLs with I(34) were able to decode CGC, whereas only the singly modified ASL(Arg1,2)(ICG) with I(34) was able to decode CGA. The dissociation constants for all codon bindings were physiologically relevant (0.4-1.4 μM). However, with the introduction of s(2)C(32) or m(2)A(37) to ASL(Arg1,2)(ICG), the maximum amount of ASL bound to CGU and CGC was significantly reduced. These results suggest that, by allowing loop flexibility, the modifications modulate the conformation of the ASL(Arg1,2), which takes one structure free in solution and two others when bound to the cognate arginyl-tRNA synthetase or to codons on the ribosome where modifications reduce or restrict binding to specific codons. Copyright © 2011 Elsevier Ltd. All rights reserved.

Modification of gray iron produced by induction melting with barium strontium

NASA Astrophysics Data System (ADS)

Modzelevskaya, G.; Feoktistov, A. V.; Selyanin, I. F.; Kutsenko, A. I.; Kutsenko, A. A.

2016-09-01

The article provides analysis of results of gray iron experimental melts in induction furnace and the following melt modification with barium-strontium carbonate (BSC-2). It is shown that modification positively affects mechanical and casting properties and as-cast iron structure. It was established that BSC-2 granulated immediately prior to use has greater impact on melt than BSC-2 of the same faction, supplied by the manufacturer.

Posttranslational Modifications Regulate the Postsynaptic Localization of PSD-95.

PubMed

Vallejo, Daniela; Codocedo, Juan F; Inestrosa, Nibaldo C

2017-04-01

The postsynaptic density (PSD) consists of a lattice-like array of interacting proteins that organizes and stabilizes synaptic receptors, ion channels, structural proteins, and signaling molecules required for normal synaptic transmission and synaptic function. The scaffolding and hub protein postsynaptic density protein-95 (PSD-95) is a major element of central chemical synapses and interacts with glutamate receptors, cell adhesion molecules, and cytoskeletal elements. In fact, PSD-95 can regulate basal synaptic stability as well as the activity-dependent structural plasticity of the PSD and, therefore, of the excitatory chemical synapse. Several studies have shown that PSD-95 is highly enriched at excitatory synapses and have identified multiple protein structural domains and protein-protein interactions that mediate PSD-95 function and trafficking to the postsynaptic region. PSD-95 is also a target of several signaling pathways that induce posttranslational modifications, including palmitoylation, phosphorylation, ubiquitination, nitrosylation, and neddylation; these modifications determine the synaptic stability and function of PSD-95 and thus regulate the fates of individual dendritic spines in the nervous system. In the present work, we review the posttranslational modifications that regulate the synaptic localization of PSD-95 and describe their functional consequences. We also explore the signaling pathways that induce such changes.

78 FR 63861 - Modification of Class B Airspace; Minneapolis, MN

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-25

.... The committee did however indicate the proposed modifications would impact the Minnesota Soaring Club... Impact Assessment The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the Uruguay Round...

Partners in crime: The role of tandem modules in gene transcription.

PubMed

Sharma, Rajal; Zhou, Ming-Ming

2015-09-01

Histones and their modifications play an important role in the regulation of gene transcription. Numerous modifications, such as acetylation, phosphorylation, methylation, ubiquitination, and SUMOylation, have been described. These modifications almost always co-occur and thereby increase the combinatorial complexity of post-translational modification detection. The domains that recognize these histone modifications often occur in tandem in the context of larger proteins and complexes. The presence of multiple modifications can positively or negatively regulate the binding of these tandem domains, influencing downstream cellular function. Alternatively, these tandem domains can have novel functions from their independent parts. Here we summarize structural and functional information known about major tandem domains and their histone binding properties. An understanding of these interactions is key for the development of epigenetic therapy. © 2015 The Protein Society.

Sleep loss and structural plasticity.

PubMed

Areal, Cassandra C; Warby, Simon C; Mongrain, Valérie

2017-06-01

Wakefulness and sleep are dynamic states during which brain functioning is modified and shaped. Sleep loss is detrimental to many brain functions and results in structural changes localized at synapses in the nervous system. In this review, we present and discuss some of the latest observations of structural changes following sleep loss in some vertebrates and insects. We also emphasize that these changes are region-specific and cell type-specific and that, most importantly, these structural modifications have functional roles in sleep regulation and brain functions. Selected mechanisms driving structural modifications occurring with sleep loss are also discussed. Overall, recent research highlights that extending wakefulness impacts synapse number and shape, which in turn regulate sleep need and sleep-dependent learning/memory. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Quantitative Assessment of Lip Movements in Different Facial Expressions Through 3-Dimensional on 3-Dimensional Superimposition: A Cross-Sectional Study.

PubMed

Gibelli, Daniele; Codari, Marina; Pucciarelli, Valentina; Dolci, Claudia; Sforza, Chiarella

2017-11-23

The quantitative assessment of facial modifications from mimicry is of relevant interest for the rehabilitation of patients who can no longer produce facial expressions. This study investigated a novel application of 3-dimensional on 3-dimensional superimposition for facial mimicry. This cross-sectional study was based on 10 men 30 to 40 years old who underwent stereophotogrammetry for neutral, happy, sad, and angry expressions. Registration of facial expressions on the neutral expression was performed. Root mean square (RMS) point-to-point distance in the labial area was calculated between each facial expression and the neutral one and was considered the main parameter for assessing facial modifications. In addition, effect size (Cohen d) was calculated to assess the effects of labial movements in relation to facial modifications. All participants were free from possible facial deformities, pathologies, or trauma that could affect facial mimicry. RMS values of facial areas differed significantly among facial expressions (P = .0004 by Friedman test). The widest modifications of the lips were observed in happy expressions (RMS, 4.06 mm; standard deviation [SD], 1.14 mm), with a statistically relevant difference compared with the sad (RMS, 1.42 mm; SD, 1.15 mm) and angry (RMS, 0.76 mm; SD, 0.45 mm) expressions. The effect size of labial versus total face movements was limited for happy and sad expressions and large for the angry expression. This study found that a happy expression provides wider modifications of the lips than the other facial expressions and suggests a novel procedure for assessing regional changes from mimicry. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

CDUCT-LaRC Status - Shear Layer Refraction and Noise Radiation

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Farassat, F.

2006-01-01

A proposed boundary condition accounting for shear layer effects within the Ffowcs Williams-Hawkings radiation module of the CDUCT-LaRC code is investigated. The development and numerical justification of the boundary condition formulation are reviewed. An initial assessment of the effectiveness of the shear layer correction is conducted through comparison with experimental data. Preliminary results indicate that the correction provides physically meaningful modifications of the baseline predicted directivity patterns. Trends of peak directivity steepening and shifting that appeared in predicted patterns were found to follow similar structures in measured data, particularly at higher radiation angles.

An assessment of warm fog: Nucleation, control, and recommended research

NASA Technical Reports Server (NTRS)

Corrin, M. L.; Connell, J. R.; Gero, A. J.

1974-01-01

A state-of-the-art survey is given of warm fog research which has been performed up to, and including, 1974. Topics covered are nucleation, growth, coalescence, fog structures and visibility, effects of surface films, drop size spectrum, optical properties, instrumentation, liquid water content, condensation nuclei. Included is a summary of all reported fog modification experiments. Additional data is provided on air flow, turbulence, a summary of recommendations on instruments to be developed for determining turbulence, air flow, etc., as well as recommendations of various fog research tasks which should be performed for a better understanding of fog microphysics.

Technology-based functional assessment in early childhood intervention: a pilot study.

PubMed

Khetani, Mary A; McManus, Beth M; Arestad, Kristen; Richardson, Zachary; Charlifue-Smith, Renee; Rosenberg, Cordelia; Rigau, Briana

2018-01-01

Electronic patient-reported outcomes (e-PROs) may provide valid and feasible options for obtaining family input on their child's functioning for care planning and outcome monitoring, but they have not been adopted into early intervention (EI). The purpose of this pilot study was to evaluate the feasibility of implementing technology-based functional assessment into EI practice and to examine child, family, service, and environmental correlates of caregiver-reported child functioning in the home. In a cross-sectional design, eight individual EI providers participated in a 90-min technology-based functional assessment training to recruit participants and a 60-min semi-structured focus group post data collection. Participants completed the Young Children's Participation and Environment Measure (YC-PEM) home section online and Pediatric Evaluation of Disability Inventory Computer Adaptive Test (PEDI-CAT) via iPad. Participants' EI service use data were obtained from administrative records. A total of 37 caregivers of children between 6 and 35 months old (mean age = 19.4, SD = 7.7) enrolled, a rate of 44% (37/84) in 2.5 months. Providers suggested expanding staff training, gathering data during scheduled evaluations, and providing caregivers and providers with access to assessment summaries. Caregivers wanted their child's participation to change in 56% of home activities. Lower caregiver education and higher EI intensity were related to less child involvement in home activities. Implementing technology-based functional assessment is feasible with modifications, and these data can be useful for highlighting child, family, and EI service correlates of caregiver-reported child functioning that merit further study. Feasibility results informed protocol modifications related to EI provider training, timing of data collection, and management of EI service use data extraction, as preparation for a subsequent scale-up study that is underway.

Implementing a Loosely Coupled Fluid Structure Interaction Finite Element Model in PHASTA

NASA Astrophysics Data System (ADS)

Pope, David

Fluid Structure Interaction problems are an important multi-physics phenomenon in the design of aerospace vehicles and other engineering applications. A variety of computational fluid dynamics solvers capable of resolving the fluid dynamics exist. PHASTA is one such computational fluid dynamics solver. Enhancing the capability of PHASTA to resolve Fluid-Structure Interaction first requires implementing a structural dynamics solver. The implementation also requires a correction of the mesh used to solve the fluid equations to account for the deformation of the structure. This results in mesh motion and causes the need for an Arbitrary Lagrangian-Eulerian modification to the fluid dynamics equations currently implemented in PHASTA. With the implementation of both structural dynamics physics, mesh correction, and the Arbitrary Lagrangian-Eulerian modification of the fluid dynamics equations, PHASTA is made capable of solving Fluid-Structure Interaction problems.

Large structural modification with conserved conformation: analysis of delta(3)-fused aryl prolines in model beta-turns.

PubMed

Jeannotte, Guillaume; Lubell, William D

2004-11-10

For the first time, the influence of a fused Delta3-arylproline on peptide conformation has been studied by the synthesis and comparison of the conformations of peptides containing proline and pyrrolo-proline, 3 (PyPro). Pyrrolo-proline was demonstrated to be a conservative replacement for Pro in model beta-turns, 4 and 5, as shown by their similar DMSO titration curves, cis/trans-isomer populations, and NOESY spectral data. Pyrrolo-proline may thus be used for studying the structure activity relationships of Pro-containing peptides with minimal modification of secondary structures.

Near-blade flow structure modification

NASA Astrophysics Data System (ADS)

Kura, T.; Fornalik-Wajs, E.

2016-10-01

In this paper, the importance of near-blade flow structure influence on the performance of a centrifugal compressor was discussed. The negative effects of eddies and secondary flows appearance were described, together with the proposal of their reduction. Three-dimensional analyses were performed for the rotors. Focus was placed on the blade's 3D curvature impact on the efficiency of compression, and the influence of blade-shroud tip existence. A few design proposals were investigated - their performance maps were the basis of further analysis. Proposed modification of blade shape changed the near-blade flow structure and improved the compressor performance.

Development of diagnostic and treatment strategies for glaucoma through understanding and modification of scleral and lamina cribrosa connective tissue

PubMed Central

Quigley, Harry A.; Cone, Frances E.

2013-01-01

There is considerable evidence that the state of ocular connective tissues and their response in glaucomatous disease affects the degree of glaucoma damage. Both experimental and clinical data suggest that improved diagnostic and prognostic information could be derived from assessment of the mechanical responsiveness of the sclera and lamina cribrosa to intraocular pressure (IOP). Controlled mutagenesis of the sclera has produced a mouse strain that is relatively resistant to increased IOP. Alteration of the baseline scleral state could be accomplished through either increased cross-linking of fibrillar components or their reduction. The sclera is a dynamic structure, altering its structure and behavior in response to IOP change. The biochemical pathways that control these responses are fertile areas for new glaucoma treatments. PMID:23535950

Structural Dynamics Modeling of HIRENASD in Support of the Aeroelastic Prediction Workshop

NASA Technical Reports Server (NTRS)

Wieseman, Carol; Chwalowski, Pawel; Heeg, Jennifer; Boucke, Alexander; Castro, Jack

2013-01-01

An Aeroelastic Prediction Workshop (AePW) was held in April 2012 using three aeroelasticity case study wind tunnel tests for assessing the capabilities of various codes in making aeroelasticity predictions. One of these case studies was known as the HIRENASD model that was tested in the European Transonic Wind Tunnel (ETW). This paper summarizes the development of a standardized enhanced analytical HIRENASD structural model for use in the AePW effort. The modifications to the HIRENASD finite element model were validated by comparing modal frequencies, evaluating modal assurance criteria, comparing leading edge, trailing edge and twist of the wing with experiment and by performing steady and unsteady CFD analyses for one of the test conditions on the same grid, and identical processing of results.

Influence of succinylation on the conformation of yak casein micelles.

PubMed

Yang, Min; Cui, Na; Fang, Yan; Shi, Ying; Yang, Jitao; Wang, Jiangyu

2015-07-15

Succinylation modifies the physicochemical characteristics and improves the functional properties of proteins. This study assessed the effects of succinylation on the conformation of yak casein micelles with seven degree of modification. The results revealed that succinylation contributed to the dissociation of casein micelles. With the increase of succinylated degree, soluble nitrogen and minerals content increased, while casein micelle size and polydispersity index of micelles decreased. Succinylation affected the spatial conformation of yak casein micelles: turn decreased, ß-sheet and α-helix increased, and irregular structure were non-significantly affected. The intrinsic and ANS fluorescence intensity decreased and the maximum emission wavelength shifted red with increasing succinylation. Based on the results, the structure of yak casein micelles was characteristic of the sub-micelle model. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mass spectrometry based structural analysis and systems immunoproteomics strategies for deciphering the host response to endotoxin.

PubMed

Khan, Mohd M; Ernst, Orna; Sun, Jing; Fraser, Iain D C; Ernst, Robert K; Goodlett, David R; Nita-Lazar, Aleksandra

2018-06-24

One cause of sepsis is systemic maladaptive immune response of the host to bacteria and specifically, to Gram-negative bacterial outer membrane glycolipid lipopolysaccharide (LPS). On the host myeloid cell surface, proinflammatory LPS activates the innate immune system via Toll-like receptor-4 (TLR4)/myeloid differentiation factor-2 (MD2) complex. Intracellularly, LPS is also sensed by the noncanonical inflammasome through caspase-11 in mice and 4/5 in humans. The minimal functional determinant for innate immune activation is the membrane anchor of LPS called lipid A. Even subtle modifications to the lipid A scaffold can enable, diminish, or abolish immune activation. Bacteria are known to modify their LPS structure during environmental stress, and infection of hosts to alter cellular immune phenotypes. In this review, we describe how mass spectrometry (MS)-based structural analysis of endotoxin helped uncover major determinations of molecular pathogenesis. Through characterization of LPS modifications, we now better understand resistance to antibiotics and cationic antimicrobial peptides, as well as how the environment impacts overall endotoxin structure. In addition, MS-based systems immunoproteomics approaches can assist in elucidating the immune response against LPS. Many regulatory proteins have been characterized through proteomics and global/targeted analysis of protein modifications, enabling the discovery and characterization of novel endotoxin-mediated protein translational modifications (PTMs). Copyright © 2018. Published by Elsevier Ltd.

Effect of surface topological structure and chemical modification of flame sprayed aluminum coatings on the colonization of Cylindrotheca closterium on their surfaces

NASA Astrophysics Data System (ADS)

Chen, Xiuyong; He, Xiaoyan; Suo, Xinkun; Huang, Jing; Gong, Yongfeng; Liu, Yi; Li, Hua

2016-12-01

Biofouling is one of the major problems for the coatings used for protecting marine infrastructures during their long-term services. Regulation in surface structure and local chemistry is usually the key for adjusting antifouling performances of the coatings. In this study, flame sprayed multi-layered aluminum coatings with micropatterned surfaces were constructed and the effects of their surface structure and chemistry on the settlement of typical marine diatoms were investigated. Micropatterned topographical morphology of the coatings was constructed by employing steel mesh as a shielding plate during the coating deposition. A silicone elastomer layer for sealing and interconnection was further brush-coated on the micropatterned coatings. Additional surface modification was made using zwitterionic molecules via DOPA linkage. The surface-modified coatings resist effectively colonization of Cylindrotheca closterium. This is explained by the quantitative examination of a simplified conditioning layer that deteriorated adsorption of bovine calf serum proteins on the zwitterionic molecule-treated samples is revealed. The colonization behaviors of the marine diatoms are markedly influenced by the micropatterned topographical morphology. Either the surface micropatterning or the surface modification by zwitterionic molecules enhances antimicrobial ability of the coatings. However, the combined micropatterned structure and zwitterionic modification do not show synergistic effect. The results give insight into anti-corrosion/fouling applications of the modified aluminum coatings in the marine environment.

Structural and optical modification in 4H-SiC following 30 keV silver ion irradiation

NASA Astrophysics Data System (ADS)

Kaushik, Priya Darshni; Aziz, Anver; Siddiqui, Azher M.; Lakshmi, G. B. V. S.; Syväjärvi, Mikael; Yakimova, Rositsa; Yazdi, G. Reza

2018-05-01

The market of high power, high frequency and high temperature based electronic devices is captured by SiC due to its superior properties like high thermal conductivity and high sublimation temperature and also due to the limitation of silicon based electronics in this area. There is a need to investigate effect of ion irradiation on SiC due to its application in outer space as outer space is surrounded both by low and high energy ion irradiations. In this work, effect of low energy ion irradiation on structural and optical property of 4H-SiC is investigated. ATR-FTIR is used to study structural modification and UV-Visible spectroscopy is used to study optical modifications in 4H-SiC following 30 keV Ag ion irradiation. FTIR showed decrease in bond density of SiC along the ion path (track) due to the creation of point defects. UV-Visible absorption spectra showed decrease in optical band gap from 3.26 eV to 2.9 eV. The study showed degradation of SiC crystallity and change in optical band gap following low energy ion irradiation and should be addressed while fabricationg devices based on SiC for outer space application. Additionally, this study provides a platform for introducing structural and optical modification in 4H-SiC using ion beam technology in a controlled manner.

Structure modulation of helix 69 from Escherichia coli 23S ribosomal RNA by pseudouridylations

PubMed Central

Jiang, Jun; Aduri, Raviprasad; Chow, Christine S.; SantaLucia, John

2014-01-01

Helix 69 (H69) is a 19-nt stem-loop region from the large subunit ribosomal RNA. Three pseudouridine (Ψ) modifications clustered in H69 are conserved across phylogeny and known to affect ribosome function. To explore the effects of Ψ on the conformations of Escherichia coli H69 in solution, nuclear magnetic resonance spectroscopy was used to reveal the structural differences between H69 with (ΨΨΨ) and without (UUU) Ψ modifications. Comparison of the two structures shows that H69 ΨΨΨ has the following unique features: (i) the loop region is closed by a Watson–Crick base pair between Ψ1911 and A1919, which is potentially reinforced by interactions involving Ψ1911N1H and (ii) Ψ modifications at loop residues 1915 and 1917 promote base stacking from Ψ1915 to A1918. In contrast, the H69 UUU loop region, which lacks Ψ modifications, is less organized. Structure modulation by Ψ leads to alteration in conformational behavior of the 5' half of the H69 loop region, observed as broadening of C1914 non-exchangeable base proton resonances in the H69 ΨΨΨ nuclear magnetic resonance spectra, and plays an important biological role in establishing the ribosomal intersubunit bridge B2a and mediating translational fidelity. PMID:24371282

Application of Natural Mineral Additives in Construction

NASA Astrophysics Data System (ADS)

Linek, Malgorzata; Nita, Piotr; Wolka, Paweł; Zebrowski, Wojciech

2017-12-01

The article concerns the idea of using selected mineral additives in the pavement quality concrete composition. The basis of the research paper was the modification of cement concrete intended for airfield pavements. The application of the additives: metakaolonite and natural zeolite was suggested. Analyses included the assessment of basic physical properties of modifiers. Screening analysis, assessment of micro structure and chemical microanalysis were conducted in case of these materials. The influence of the applied additives on the change of concrete mix parameters was also presented. The impact of zeolite and metakaolinite on the mix density, oxygen content and consistency class was analysed. The influence of modifiers on physical and mechanical changes of the hardened cement concrete was discussed (concrete density, compressive strength and bending strength during fracturing) in diversified research periods. The impact of the applied additives on the changes of internal structure of cement concrete was discussed. Observation of concrete micro structure was conducted using the scanning electron microscope. According to the obtained lab test results, parameters of the applied modifiers and their influence on changes of internal structure of cement concrete are reflected in the increase of mechanical properties of pavement quality concrete. The increase of compressive and bending strength in case of all analysed research periods was proved.

Acetaldehyde-induced structural and conformational alterations in human immunoglobulin G: A physicochemical and multi-spectroscopic study.

PubMed

Waris, Sana; Habib, Safia; Tantry, Irfan Qadir; Khan, Rizwan Hasan; Mahmood, Riaz; Ali, Asif

2018-07-01

Acetaldehyde is a reactive aldehyde produced as an intermediate of alcohol metabolism and tobacco pyrolysis. It has the potential to interact with different biomolecules in various tissues which results in the formation of stable, unstable and covalent adducts. This causes structural and functional modifications that may lead to severe complications such as cancer. This study has probed the structural modifications in human immunoglobulin G (IgG) as a function of different concentrations of acetaldehyde in the presence of reducing agent, sodium borohydride. Acetaldehyde mediated modifications in IgG have been characterised by various physicochemical techniques. UV-spectrophotometry showed that acetaldehyde modified IgG exhibited marked increase in hyperchromicity. Fluorescence studies revealed a significant quenching of tryptophan fluorescence which resulted in loss of β-sheet secondary structure that was confirmed by circular dichroic analysis. Gross structural changes in the morphology of IgG were confirmed by increase in mass and hydrodynamic radius of this glycoprotein along with the appearance of fibrillar structures in modified IgG, when compared to the granular structure of the native form of IgG observed by scanning electron microscope. The results indicate that acetaldehyde causes alterations in the secondary and tertiary structure of the protein leading to diminution of normal function of IgG molecule. Copyright © 2018 Elsevier B.V. All rights reserved.

49 CFR Appendix A to Part 37 - Modifications to Standards for Accessible Transportation Facilities

Code of Federal Regulations, 2010 CFR

2010-10-01

... steps may have to travel compared to the general public. 406.8—Modification to 406 of Appendix D to 36... rail, commuter rail, and intercity rail systems where it is not operationally or structurally feasible...

Sorption of lead ions on diatomite and manganese oxides modified diatomite.

PubMed

Al-Degs, Y; Khraisheh, M A; Tutunji, M F

2001-10-01

Naturally occurring diatomaceous earth (diatomite) has been tested as a potential sorbent for Pb(II) ions. The intrinsic exchange properties were further improved by modification with manganese oxides. Modified adsorbent (referred to as Mn-diatomite) showed a higher tendency for adsorbing lead ions from solution at pH 4. The high performance exhibited by Mn-diatomite was attributed to increased surface area and higher negative surface charge after modification. Scanning electron microscope pictures revealed a birnessite structure of manganese oxides, which was featured by a plate-like-crystal structure. Diatomite filtration quality was improved after modification by manganese oxides. Good filtration qualities combined with high exchange capacity emphasised the potential use of Mn-diatomite in filtration systems.

Mapping RNA Structure In Vitro with SHAPE Chemistry and Next-Generation Sequencing (SHAPE-Seq).

PubMed

Watters, Kyle E; Lucks, Julius B

2016-01-01

Mapping RNA structure with selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) chemistry has proven to be a versatile method for characterizing RNA structure in a variety of contexts. SHAPE reagents covalently modify RNAs in a structure-dependent manner to create adducts at the 2'-OH group of the ribose backbone at nucleotides that are structurally flexible. The positions of these adducts are detected using reverse transcriptase (RT) primer extension, which stops one nucleotide before the modification, to create a pool of cDNAs whose lengths reflect the location of SHAPE modification. Quantification of the cDNA pools is used to estimate the "reactivity" of each nucleotide in an RNA molecule to the SHAPE reagent. High reactivities indicate nucleotides that are structurally flexible, while low reactivities indicate nucleotides that are inflexible. These SHAPE reactivities can then be used to infer RNA structures by restraining RNA structure prediction algorithms. Here, we provide a state-of-the-art protocol describing how to perform in vitro RNA structure probing with SHAPE chemistry using next-generation sequencing to quantify cDNA pools and estimate reactivities (SHAPE-Seq). The use of next-generation sequencing allows for higher throughput, more consistent data analysis, and multiplexing capabilities. The technique described herein, SHAPE-Seq v2.0, uses a universal reverse transcription priming site that is ligated to the RNA after SHAPE modification. The introduced priming site allows for the structural analysis of an RNA independent of its sequence.

Workstations for people with disabilities: an example of a virtual reality approach

PubMed Central

Budziszewski, Paweł; Grabowski, Andrzej; Milanowicz, Marcin; Jankowski, Jarosław

2016-01-01

This article describes a method of adapting workstations for workers with motion disability using computer simulation and virtual reality (VR) techniques. A workstation for grinding spring faces was used as an example. It was adjusted for two people with a disabled right upper extremity. The study had two stages. In the first, a computer human model with a visualization of maximal arm reach and preferred workspace was used to develop a preliminary modification of a virtual workstation. In the second stage, an immersive VR environment was used to assess the virtual workstation and to add further modifications. All modifications were assessed by measuring the efficiency of work and the number of movements involved. The results of the study showed that a computer simulation could be used to determine whether a worker with a disability could access all important areas of a workstation and to propose necessary modifications. PMID:26651540

Unhealthy behaviour modification, psychological distress, and 1-year survival in cardiac rehabilitation.

PubMed

Gostoli, Sara; Roncuzzi, Renzo; Urbinati, Stefano; Morisky, Donald E; Rafanelli, Chiara

2016-11-01

Cardiac rehabilitation (CR) is considered the recommended secondary prevention treatment for cardiovascular diseases (CVD), in terms of health behaviours and, secondarily, better cardiac outcomes promotion. However, the role of psychiatric and psychosomatic distress on the efficacy of CR is unclear. This research aimed to evaluate the impact of CR on unhealthy behaviour modification and cardiac course, considering the moderating role of depression, anxiety, and psychosomatic syndromes. A longitudinal design between and within groups was employed. The assessment was repeated four times: at admission to CR (T1), at discharge (T2), 6 (T3) and 12 months following CR completion (T4). One hundred and eight patients undergoing CR versus 85 patients with CVD not referred to CR, underwent psychiatric, psychosomatic, and health behaviour assessment. The assessment included the Structured Clinical Interview for DSM-IV (depression and anxiety), the interview based on Diagnostic Criteria for Psychosomatic Research, GOSPEL Study questionnaire (health behaviours), Pittsburgh Sleep Quality Index, and 8-item Morisky Medication Adherence Scale. Cardiac rehabilitation was associated with maintenance of physical activity, improvement of behavioural aspects related to food consumption, stress management, and sleep quality. On the contrary, CR was not associated with weight loss, healthy diet, and medication adherence. Depression and psychosomatic syndromes seem to moderate the modification of specific health-related behaviours (physical activity, behavioural aspects of food consumption, stress management, and pharmacological adherence). In CR settings, an integrated assessment including both psychiatric and psychosomatic syndromes is needed to address psychological factors associated with unhealthy behaviour modification. Statement of contribution What is already known on this subject? Cardiac rehabilitation (CR) is considered a class 1A treatment recommendation and the most cost-effective model of secondary prevention to reduce cardiovascular events. There is evidence about the association between psychological distress and both unhealthy behaviour and cardiac course. Depression and psychosomatic distress, such as type A behaviour and demoralization, are frequently associated with CVD course. However, the role of psychiatric and psychosomatic distress in CR is not well known. What does this study add? CR exerted a protective effect on physical activity and a positive effect on eating behaviour, stress management, and quality of sleep. CR did not show any particular effect on smoking, overweight/obesity, dietary habits, medication adherence, and patients' 1-year survival. Findings from this study suggest the importance to consider specific psychological and psychosomatic aspects in affecting lifestyle. © 2016 The British Psychological Society.

Surface modification for interaction study with bacteria and preosteoblast cells

NASA Astrophysics Data System (ADS)

Song, Qing

Surface modification plays a pivotal role in bioengineering. Polymer coatings can provide biocompatibility and biofunctionalities to biomaterials through surface modification. In this dissertation, initiated chemical vapor deposition (iCVD) was utilized to coat two-dimensional (2D) and three-dimensional (3D) substrates with differently charged polyelectrolytes in order to generate antimicrobial and osteocompatible biomaterials. ICVD is a modified CVD technique that enables surface modification in an all-dry condition without substrate damage and solvent contamination. The free-radical polymerization allows the vinyl polymers to conformally coat on various micro- and nano-structured substrates and maintains the delicate structure of the functional groups. The vapor deposition of polycations provided antimicrobial activity to planar and porous substrates through destroying the negatively charged bacterial membrane and brought about high contact-killing efficiency (99.99%) against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli. Additionally, the polyampholytes synthesized by iCVD exhibited excellent antifouling performance against the adhesion of Gram-positive Listeria innocua and Gram-negative E. coli in phosphate buffered saline (PBS). Their antifouling activities were attributed to the electrostatic interaction and hydration layers that served as physical and energetic barriers to prevent bacterial adhesion. The contact-killing and antifouling polymers synthesized by iCVD can be applied to surface modification of food processing equipment and medical devices with the aim of reducing foodborne diseases and medical infections. Moreover, the charged polyelectrolyte modified 2D polystyrene surfaces displayed good osteocompatibility and enhanced osteogenesis of preosteoblast cells than the un-modified polystyrene surface. In order to promote osteoinduction of hydroxyapatite (HA) scaffolds, bioinspired polymer-controlled mineralization was conducted on the polyelectrolyte modified HA scaffolds. The mineralized scaffolds stimulated osteogenesis of preosteoblast cells compared with the control HA scaffolds. Therefore, the surface modification through vapor deposition of polyelectrolytes and polymer-controlled mineralization can improve osteoinduction of bone materials. In summary, the iCVD-mediated surface modification is a simple and promising approach to biofunctionalizing various structured substrates and generating antimicrobial and biocompatible biomaterials.

Secondary structure model of the RNA recognized by the reverse transcriptase from the R2 retrotransposable element.

PubMed Central

Mathews, D H; Banerjee, A R; Luan, D D; Eickbush, T H; Turner, D H

1997-01-01

RNA transcripts corresponding to the 250-nt 3' untranslated region of the R2 non-LTR retrotransposable element are recognized by the R2 reverse transcriptase and are sufficient to serve as templates in the target DNA-primed reverse transcription (TPRT) reaction. The R2 protein encoded by the Bombyx mori R2 can recognize this region from both the B. mori and Drosophila melanogaster R2 elements even though these regions show little nucleotide sequence identity. A model for the RNA secondary structure of the 3' untranslated region of the D. melanogaster R2 retrotransposon was developed by sequence comparison of 10 species aided by free energy minimization. Chemical modification experiments are consistent with this prediction. A secondary structure model for the 3' untranslated region of R2 RNA from the R2 element from B. mori was obtained by a combination of chemical modification data and free energy minimization. These two secondary structure models, found independently, share several common sites. This study shows the utility of combining free energy minimization, sequence comparison, and chemical modification to model an RNA secondary structure. PMID:8990394

Chemical and Conformational Diversity of Modified Nucleosides Affects tRNA Structure and Function.

PubMed

Väre, Ville Y P; Eruysal, Emily R; Narendran, Amithi; Sarachan, Kathryn L; Agris, Paul F

2017-03-16

RNAs are central to all gene expression through the control of protein synthesis. Four major nucleosides, adenosine, guanosine, cytidine and uridine, compose RNAs and provide sequence variation, but are limited in contributions to structural variation as well as distinct chemical properties. The ability of RNAs to play multiple roles in cellular metabolism is made possible by extensive variation in length, conformational dynamics, and the over 100 post-transcriptional modifications. There are several reviews of the biochemical pathways leading to RNA modification, but the physicochemical nature of modified nucleosides and how they facilitate RNA function is of keen interest, particularly with regard to the contributions of modified nucleosides. Transfer RNAs (tRNAs) are the most extensively modified RNAs. The diversity of modifications provide versatility to the chemical and structural environments. The added chemistry, conformation and dynamics of modified nucleosides occurring at the termini of stems in tRNA's cloverleaf secondary structure affect the global three-dimensional conformation, produce unique recognition determinants for macromolecules to recognize tRNAs, and affect the accurate and efficient decoding ability of tRNAs. This review will discuss the impact of specific chemical moieties on the structure, stability, electrochemical properties, and function of tRNAs.

Nanoparticles for Protein Sensing in Primary Containers: Interaction Analysis and Application.

PubMed

Pérez Medina Martínez, Víctor; Espinosa-de la Garza, Carlos E; Méndez-Silva, Diego A; Bolívar-Vichido, Mariana; Flores-Ortiz, Luis F; Pérez, Néstor O

2018-05-01

Silver nanoparticles (AgNPs) are known to interact with proteins, leading to modifications of the plasmonic absorption that can be used to monitor this interaction, entailing a promising application for sensing adsorption of therapeutic proteins in primary containers. First, transmission electron microscopy in combination with plasmonic absorption and light scattering responses were used to characterize AgNPs and protein-AgNP complexes, including its concentration dependence, using two therapeutic molecules as models: a monoclonal antibody (mAb) and a synthetic copolymer (SC). Upon interaction, a protein corona was formed around AgNPs with the consequent shifting and broadening of their characteristic surface plasmon resonance (SPR) band (400 nm) to 410 nm and longer wavelenghts. Additional studies revealed secondary and three-dimensional structure modifications of model proteins upon interaction with AgNPs by circular dichroism and fluorescence techniques, respectively. Based on the modification of the SPR condition of AgNPs upon interaction with proteins, we developed a novel protein-sensing application of AgNPs in primary containers. This strategy was used to conduct a compatibility assessment of model proteins towards five commercially available prefillable glass syringe (PFS) models. mAb- and SC-exposed PFSs showed that 74 and 94% of cases were positive for protein adsorption, respectively. Interestingly, protein adsorption on 15% of total tested PFSs was negligible (below the nanogram level). Our results highlight the need of a case-by-case compatibility assessment of therapeutic proteins and their primary containers. This strategy has the potential to be easily applied on other containers and implemented during early-stage product development by pharmaceutical companies and for routine use during batch release by packaging manufacturers.

Insights into molecular plasticity in protein complexes from Trm9-Trm112 tRNA modifying enzyme crystal structure

PubMed Central

Létoquart, Juliette; van Tran, Nhan; Caroline, Vonny; Aleksandrov, Alexey; Lazar, Noureddine; van Tilbeurgh, Herman; Liger, Dominique; Graille, Marc

2015-01-01

Most of the factors involved in translation (tRNA, rRNA and proteins) are subject to post-transcriptional and post-translational modifications, which participate in the fine-tuning and tight control of ribosome and protein synthesis processes. In eukaryotes, Trm112 acts as an obligate activating platform for at least four methyltransferases (MTase) involved in the modification of 18S rRNA (Bud23), tRNA (Trm9 and Trm11) and translation termination factor eRF1 (Mtq2). Trm112 is then at a nexus between ribosome synthesis and function. Here, we present a structure-function analysis of the Trm9-Trm112 complex, which is involved in the 5-methoxycarbonylmethyluridine (mcm5U) modification of the tRNA anticodon wobble position and hence promotes translational fidelity. We also compare the known crystal structures of various Trm112-MTase complexes, highlighting the structural plasticity allowing Trm112 to interact through a very similar mode with its MTase partners, although those share less than 20% sequence identity. PMID:26438534

Sequence and Structure Dependent DNA-DNA Interactions

NASA Astrophysics Data System (ADS)

Kopchick, Benjamin; Qiu, Xiangyun

Molecular forces between dsDNA strands are largely dominated by electrostatics and have been extensively studied. Quantitative knowledge has been accumulated on how DNA-DNA interactions are modulated by varied biological constituents such as ions, cationic ligands, and proteins. Despite its central role in biology, the sequence of DNA has not received substantial attention and ``random'' DNA sequences are typically used in biophysical studies. However, ~50% of human genome is composed of non-random-sequence DNAs, particularly repetitive sequences. Furthermore, covalent modifications of DNA such as methylation play key roles in gene functions. Such DNAs with specific sequences or modifications often take on structures other than the canonical B-form. Here we present series of quantitative measurements of the DNA-DNA forces with the osmotic stress method on different DNA sequences, from short repeats to the most frequent sequences in genome, and to modifications such as bromination and methylation. We observe peculiar behaviors that appear to be strongly correlated with the incurred structural changes. We speculate the causalities in terms of the differences in hydration shell and DNA surface structures.

DNA Base Flipping: A General Mechanism for Writing, Reading, and Erasing DNA Modifications

PubMed Central

Cheng, Xiaodong

2017-01-01

The modification of DNA bases is a classic hallmark of epigenetics. Four forms of modified cytosine—5-methylcytosine, 5-hydroxymethylcytosine, 5-formylcytosine, and 5-carboxylcytosine—have been discovered in eukaryotic DNA. In addition to cytosine carbon-5 modifications, cytosine and adenine methylated in the exocyclic amine—N4-methylcytosine and N6-methyladenine—are other modified DNA bases discovered even earlier. Each modified base can be considered a distinct epigenetic signal with broader biological implications beyond simple chemical changes. Since 1994, crystal structures of proteins and enzymes involved in writing, reading, and erasing modified bases have become available. Here, we present a structural synopsis of writers, readers, and erasers of the modified bases from prokaryotes and eukaryotes. Despite significant differences in structures and functions, they are remarkably similar regarding their engagement in flipping a target base/nucleotide within DNA for specific recognitions and/or reactions. We thus highlight base flipping as a common structural framework broadly applied by distinct classes of proteins and enzymes across phyla for epigenetic regulations of DNA. PMID:27826845

Structural modifications induced by ion irradiation and temperature in boron carbide B4C

NASA Astrophysics Data System (ADS)

Victor, G.; Pipon, Y.; Bérerd, N.; Toulhoat, N.; Moncoffre, N.; Djourelov, N.; Miro, S.; Baillet, J.; Pradeilles, N.; Rapaud, O.; Maître, A.; Gosset, D.

2015-12-01

Already used as neutron absorber in the current French nuclear reactors, boron carbide (B4C) is also considered in the future Sodium Fast Reactors of the next generation (Gen IV). Due to severe irradiation conditions occurring in these reactors, it is of primary importance that this material presents a high structural resistance under irradiation, both in the ballistic and electronic damage regimes. Previous works have shown an important structural resistance of boron carbide even at high neutron fluences. Nevertheless, the structural modification mechanisms due to irradiation are not well understood. Therefore the aim of this paper is to study structural modifications induced in B4C samples in different damage regimes. The boron carbide pellets were shaped and sintered by using spark plasma sintering method. They were then irradiated in several conditions at room temperature or 800 °C, either by favoring the creation of ballistic damage (between 1 and 3 dpa), or by favoring the electronic excitations using 100 MeV swift iodine ions (Se ≈ 15 keV/nm). Ex situ micro-Raman spectroscopy and Doppler broadening of annihilation radiation technique with variable energy slow positrons were coupled to follow the evolution of the B4C structure under irradiation.

Assessment of the effects of multiple extreme floods on flow and transport processes under competing flood protection and environmental management strategies.

PubMed

Tu, Tongbi; Carr, Kara J; Ercan, Ali; Trinh, Toan; Kavvas, M Levent; Nosacka, John

2017-12-31

Extreme floods are regarded as one of the most catastrophic natural hazards and can result in significant morphological changes induced by pronounced sediment erosion and deposition processes over the landscape. However, the effects of extreme floods of different return intervals on the floodplain and river channel morphological evolution with the associated sediment transport processes are not well explored. Furthermore, different basin management action plans, such as engineering structure modifications, may also greatly affect the flood inundation, sediment transport, solute transport and morphological processes within extreme flood events. In this study, a coupled two-dimensional hydrodynamic, sediment transport and morphological model is applied to evaluate the impact of different river and basin management strategies on the flood inundation, sediment transport dynamics and morphological changes within extreme flood events of different magnitudes. The 10-year, 50-year, 100-year and 200-year floods are evaluated for the Lower Cache Creek system in California under existing condition and a potential future modification scenario. Modeling results showed that select locations of flood inundation within the study area tend to experience larger inundation depth and more sediment is likely to be trapped in the study area under potential modification scenario. The proposed two dimensional flow and sediment transport modeling approach implemented with a variety of inflow conditions can provide guidance to decision-makers when considering implementation of potential modification plans, especially as they relate to competing management strategies of large water bodies, such as the modeling area in this study. Copyright © 2017 Elsevier B.V. All rights reserved.

Attitudes Toward Genetic Modification Research: An Analysis of the Views of the Sputnik Generation.

ERIC Educational Resources Information Center

Miller, Jon D.

1982-01-01

Utilizing data from the 1977 National Assessment of Educational Progress (NAEP) survey of young adults, summarizes attitudes toward genetic modification research and the demographic, educational, and occupational correlates of these attitudes. (Author/SK)

The Redox Proteome*

PubMed Central

Go, Young-Mi; Jones, Dean P.

2013-01-01

The redox proteome consists of reversible and irreversible covalent modifications that link redox metabolism to biologic structure and function. These modifications, especially of Cys, function at the molecular level in protein folding and maturation, catalytic activity, signaling, and macromolecular interactions and at the macroscopic level in control of secretion and cell shape. Interaction of the redox proteome with redox-active chemicals is central to macromolecular structure, regulation, and signaling during the life cycle and has a central role in the tolerance and adaptability to diet and environmental challenges. PMID:23861437

The Role of Protein-Mineral Interactions for Protein Adsorption or Fragmentation

NASA Astrophysics Data System (ADS)

Chacon, S. S.; Reardon, P.; Washton, N.; Kleber, M.

2014-12-01

Soil exo-enzymes (EE) are proteins with the capability to catalyze the depolymerization of soil organic matter (SOM). SOM must be disassembled by EEs in order to be transported through the microbial cell wall and become metabolized. One factor determining an EE's functionality is their affinity to mineral surfaces found in the soil. Our goal was to establish the range of protein modifications, either chemical or structural, as the protein becomes associated with mineral surfaces. We hypothesized that pedogenic oxides would generate more extensive chemical alterations to the protein structure than phyllosilicates. A well-characterized protein proxy (Gb1, IEP 4.0, 6.2 kDA) was adsorbed onto functionally different mineral surfaces (goethite, montmorillonite, kaolinite and birnesite) at pH 5 and pH 7. We used 1H 15N Heteronuclear Single Quantum Coherence Nuclear Magnetic Resonance Spectroscopy (HSQC NMR) to observe structural modifications in the unadsorbed Gb1 that was allowed to equilibrate during the adsorption process for kaolinite, goethite and birnessite. Solid state NMR was used to observe the structural modifications of Gb1 while adsorbed onto kaolinite and montmorillonite. Preliminary results in the HSQC NMR spectra observed no changes in the native conformation of Gb1 when allowed to interact with goethite and kaolinite while birnessite induced strong structural modification of Gb1 at an acidic pH. Our results suggest that not all mineral surfaces in soil act as sorbents for EEs and changes in their catalytic activity upon adsorption to minerals surfaces may not just be an indication of conformational changes but of fragmentation of the protein itself.

Lessons from an evolving rRNA: 16S and 23S rRNA structures from a comparative perspective

NASA Technical Reports Server (NTRS)

Gutell, R. R.; Larsen, N.; Woese, C. R.

1994-01-01

The 16S and 23S rRNA higher-order structures inferred from comparative analysis are now quite refined. The models presented here differ from their immediate predecessors only in minor detail. Thus, it is safe to assert that all of the standard secondary-structure elements in (prokaryotic) rRNAs have been identified, with approximately 90% of the individual base pairs in each molecule having independent comparative support, and that at least some of the tertiary interactions have been revealed. It is interesting to compare the rRNAs in this respect with tRNA, whose higher-order structure is known in detail from its crystal structure (36) (Table 2). It can be seen that rRNAs have as great a fraction of their sequence in established secondary-structure elements as does tRNA. However, the fact that the former show a much lower fraction of identified tertiary interactions and a greater fraction of unpaired nucleotides than the latter implies that many of the rRNA tertiary interactions remain to be located. (Alternatively, the ribosome might involve protein-rRNA rather than intramolecular rRNA interactions to stabilize three-dimensional structure.) Experimental studies on rRNA are consistent to a first approximation with the structures proposed here, confirming the basic assumption of comparative analysis, i.e., that bases whose compositions strictly covary are physically interacting. In the exhaustive study of Moazed et al. (45) on protection of the bases in the small-subunit rRNA against chemical modification, the vast majority of bases inferred to pair by covariation are found to be protected from chemical modification, both in isolated small-subunit rRNA and in the 30S subunit. The majority of the tertiary interactions are reflected in the chemical protection data as well (45). On the other hand, many of the bases not shown as paired in Fig. 1 are accessible to chemical attack (45). However, in this case a sizeable fraction of them are also protected against chemical modification (in the isolated rRNA), which suggests that considerable higher-order structure remains to be found (although all of it may not involve base-base interactions and so may not be detectable by comparative analysis). The agreement between the higher-order structure of the small-subunit rRNA and protection against chemical modification is not perfect, however; some bases shown to covary canonically are accessible to chemical modification (45).(ABSTRACT TRUNCATED AT 400 WORDS).

Structural Color of Rock Dove’s Neck Feather

NASA Astrophysics Data System (ADS)

Nakamura, Eri; Yoshioka, Shinya; Kinoshita, Shuichi

2008-12-01

It is well known that some kinds of animal have surprisingly brilliant colors showing beautiful iridescence. These colors are called structural colors, and are thought to originate from optical interference caused by periodic microstructures that have sizes comparable with the wavelength of light. However, much larger structural modifications can also play an important role in the coloration mechanism. In this paper, we show through careful optical and structural investigations that the structural color of the neck feather of rock dove, Columba livia, has a very comprehensive mechanism: the thin-layer optical interference phenomenon fundamentally produces the iridescence, while the layer structure is accompanied by various kinds of larger-size structural modifications that control the angular range of the reflection. Further, it is found that the granules containing melanin pigment exist in a localized manner to effectively enhance the contrast of the color caused by optical interference.

Assessment and Requirements of Nuclear Reaction Databases for GCR Transport in the Atmosphere and Structures

NASA Technical Reports Server (NTRS)

Cucinotta, F. A.; Wilson, J. W.; Shinn, J. L.; Tripathi, R. K.

1998-01-01

The transport properties of galactic cosmic rays (GCR) in the atmosphere, material structures, and human body (self-shielding) am of interest in risk assessment for supersonic and subsonic aircraft and for space travel in low-Earth orbit and on interplanetary missions. Nuclear reactions, such as knockout and fragmentation, present large modifications of particle type and energies of the galactic cosmic rays in penetrating materials. We make an assessment of the current nuclear reaction models and improvements in these model for developing required transport code data bases. A new fragmentation data base (QMSFRG) based on microscopic models is compared to the NUCFRG2 model and implications for shield assessment made using the HZETRN radiation transport code. For deep penetration problems, the build-up of light particles, such as nucleons, light clusters and mesons from nuclear reactions in conjunction with the absorption of the heavy ions, leads to the dominance of the charge Z = 0, 1, and 2 hadrons in the exposures at large penetration depths. Light particles are produced through nuclear or cluster knockout and in evaporation events with characteristically distinct spectra which play unique roles in the build-up of secondary radiation's in shielding. We describe models of light particle production in nucleon and heavy ion induced reactions and make an assessment of the importance of light particle multiplicity and spectral parameters in these exposures.

Environmental risk assessment for plant pests: a procedure to evaluate their impacts on ecosystem services.

PubMed

Gilioli, G; Schrader, G; Baker, R H A; Ceglarska, E; Kertész, V K; Lövei, G; Navajas, M; Rossi, V; Tramontini, S; van Lenteren, J C

2014-01-15

The current methods to assess the environmental impacts of plant pests differ in their approaches and there is a lack of the standardized procedures necessary to provide accurate and consistent results, demonstrating the complexity of developing a commonly accepted scheme for this purpose. By including both the structural and functional components of the environment threatened by invasive alien species (IAS), in particular plant pests, we propose an environmental risk assessment scheme that addresses this complexity. Structural components are investigated by evaluating the impacts of the plant pest on genetic, species and landscape diversity. Functional components are evaluated by estimating how plant pests modify ecosystem services in order to determine the extent to which an IAS changes the functional traits that influence ecosystem services. A scenario study at a defined spatial and temporal resolution is then used to explore how an IAS, as an exogenous driving force, may trigger modifications in the target environment. The method presented here provides a standardized approach to generate comparable and reproducible results for environmental risk assessment as a component of Pest Risk Analysis. The method enables the assessment of overall environmental risk which integrates the impacts on different components of the environment and their probabilities of occurrence. The application of the proposed scheme is illustrated by evaluating the environmental impacts of the invasive citrus long-horn beetle, Anoplophora chinensis. © 2013.

Position paper on the potential of inadvertent weather modification of the Florida peninsula resulting from the stabilized ground cloud

NASA Technical Reports Server (NTRS)

Bollay, E.; Bosart, L.; Droessler, E.; Jiusto, J.; Lala, G. G.; Mohnen, V.; Schaefer, V.; Squires, P.

1976-01-01

Based on the climatology of the Florida Peninsula, we assessed the risk for weather modification. Certain weather situations warrant launch rescheduling because of the risk of possible impact on hurricanes, hail formation and lightning activity, strong wind developments, and intensification of high rainfall rates. The cumulative effects of 40 launches per year on weather modification were found to be insignificant.

Structural landscape of base pairs containing post-transcriptional modifications in RNA

PubMed Central

Seelam, Preethi P.; Sharma, Purshotam

2017-01-01

Base pairs involving post-transcriptionally modified nucleobases are believed to play important roles in a wide variety of functional RNAs. Here we present our attempts toward understanding the structural and functional role of naturally occurring modified base pairs using a combination of X-ray crystal structure database analysis, sequence analysis, and advanced quantum chemical methods. Our bioinformatics analysis reveals that despite their presence in all major secondary structural elements, modified base pairs are most prevalent in tRNA crystal structures and most commonly involve guanine or uridine modifications. Further, analysis of tRNA sequences reveals additional examples of modified base pairs at structurally conserved tRNA regions and highlights the conservation patterns of these base pairs in three domains of life. Comparison of structures and binding energies of modified base pairs with their unmodified counterparts, using quantum chemical methods, allowed us to classify the base modifications in terms of the nature of their electronic structure effects on base-pairing. Analysis of specific structural contexts of modified base pairs in RNA crystal structures revealed several interesting scenarios, including those at the tRNA:rRNA interface, antibiotic-binding sites on the ribosome, and the three-way junctions within tRNA. These scenarios, when analyzed in the context of available experimental data, allowed us to correlate the occurrence and strength of modified base pairs with their specific functional roles. Overall, our study highlights the structural importance of modified base pairs in RNA and points toward the need for greater appreciation of the role of modified bases and their interactions, in the context of many biological processes involving RNA. PMID:28341704

The impact of applied behavior analysis on diverse areas of research.

PubMed Central

Kazdin, A E

1975-01-01

The impact of applied behavior analysis on various disciplines and areas of research was assessed through two major analyses. First, the relationship of applied behavior analysis to the general area of "behavior modification" was evaluated by examining the citation characteristics of journal articles in JABA and three other behavior-modification journals. Second, the penetration of applied behavior analysis into diverse areas and disciplines, including behavior modification, psychiatry, clinical psychology, education, special education, retardation, speech and hearing, counselling, and law enforcement and correction was assessed. Twenty-five journals representing diverse research areas were evaluated from 1968 to 1974 to assess the extent to which operant techniques were applied for therapeutic, rehabilitative, and educative purposes and the degree to which methodological desiderata of applied behavior analysis were met. The analyses revealed diverse publication outlets for applied behavior analysis in various disciplines. PMID:1184488

[Absorption of Uranium with Tea Oil Tree Sawdust Modified by Succinic Acid].

PubMed

Zhang, Xiao-feng; Chen, Di-yun; Peng, Yan; Liu, Yong-sheng; Xiong, Xue-ying

2015-05-01

In order to explore how the modification of succinic acid improves the adsorption of tea oil tree sawdust for uranium, the tea oil tree sawdust was modified by succinic acid, after the pretreatments of crushing, screening, alkalization and acidification. Infrared analysis indicated carboxylic acid groups and ester groups were added to the sawdust after modification, and scanning electron microscope demonstrated after modification the appearance of tea oil tree sawdust was transferred from the structure like compact and straight stripped into the structure like loose and wrinkled leaves, which meant modification increased its inner pores. By the static experiments, effects of reaction time between adsorbent and solvent, dosage of adsorbent, temperature, pH value and initial concentration of uranium were investigated. The results showed that after the modification by succinic acid, the absorption rate of tea oil tree sawdust for uranium increased significantly by about 20% in 12.5 mg · L(-1) initial concentration uranium solution. Adsorption equilibrium was achieved within 180 min, and the kinetic data can be well described by the pseudo-second-order kinetic model. The experimental adsorption isotherm followed the Langmuir and Freundlich models. In addition, the maximum adsorption amounts of tea oil tree sawdust after modification calculated from Langmuir equation raised from 21.413 3 to 31.545 7 mg · g(-1) at 35°C and pH 4.0.

Assessing the effects of microbial metabolism and metabolities on reservoir pore structure

USGS Publications Warehouse

Udegbunam, E.O.; Adkins, J.P.; Knapp, R.M.; McInerney, M.J.; Tanner, R.S.

1991-01-01

The effect of microbial treatment on pore structure of sandstone and carbonatereservoirs was determined. Understanding how different bacterial strains and their metabolic bioproducts affect reservoir pore structure will permit the prudent application of microorganisms for enhanced oil recovery. The microbial strains tested included Clostridium acetobutylicum, a polymer-producing Bacillus strain, and an unidentified halophilic anaerobe that mainly produced acids and gases. Electrical conductivity, absolute permeability, porosity and centrifuge capillary pressure were used to examine rock pore structures. Modifications of the pore structure observed in the laboratory cores included pore enlargement due to acid dissolution of carbonates and poare throat reduction due to biomass plugging. This paper shows that careful selection of microbes based on proper understanding of the reservoir petrophysical characteristics is necessary for applications of microbially enhanced oil recovery. These methods and results can be useful to field operators and laboratory researchers involved in design and screening of reservoirs for MEOR. The methods are also applicable in evaluation of formation damage caused by drilling, injection or completion fluids or stimulation caused by acids.

VIVA LA SALUD INFANTILE: Pediatric obesity treatment in an underserved Hispanic community

USDA-ARS?s Scientific Manuscript database

Pediatric obesity in the US disproportionately impacts minority populations who face socioeconomic and cultural barriers to weight management programs. The specific aim of this pilot study was to test the effectiveness of diet behavior modification or diet behavior modification plus structured aerob...

Identification of Maillard reaction induced chemical modifications on Ara h 1

USDA-ARS?s Scientific Manuscript database

The Maillard reaction is a non-enzymatic glycation reaction between proteins and reducing sugars that can modify nut allergens during thermal processing. These modifications can alter the structural and immunological properties of these allergens, and may result in increased IgE binding. Here, we ...

Extracellular Matrix Remodeling: The Common Denominator in Connective Tissue DiseasesPossibilities for Evaluation and Current Understanding of the Matrix as More Than a Passive Architecture, but a Key Player in Tissue Failure

PubMed Central

Nielsen, Mette J.; Sand, Jannie M.; Henriksen, Kim; Genovese, Federica; Bay-Jensen, Anne-Christine; Smith, Victoria; Adamkewicz, Joanne I.; Christiansen, Claus; Leeming, Diana J.

2013-01-01

Abstract Increased attention is paid to the structural components of tissues. These components are mostly collagens and various proteoglycans. Emerging evidence suggests that altered components and noncoded modifications of the matrix may be both initiators and drivers of disease, exemplified by excessive tissue remodeling leading to tissue stiffness, as well as by changes in the signaling potential of both intact matrix and fragments thereof. Although tissue structure until recently was viewed as a simple architecture anchoring cells and proteins, this complex grid may contain essential information enabling the maintenance of the structure and normal functioning of tissue. The aims of this review are to (1) discuss the structural components of the matrix and the relevance of their mutations to the pathology of diseases such as fibrosis and cancer, (2) introduce the possibility that post-translational modifications (PTMs), such as protease cleavage, citrullination, cross-linking, nitrosylation, glycosylation, and isomerization, generated during pathology, may be unique, disease-specific biochemical markers, (3) list and review the range of simple enzyme-linked immunosorbent assays (ELISAs) that have been developed for assessing the extracellular matrix (ECM) and detecting abnormal ECM remodeling, and (4) discuss whether some PTMs are the cause or consequence of disease. New evidence clearly suggests that the ECM at some point in the pathogenesis becomes a driver of disease. These pathological modified ECM proteins may allow insights into complicated pathologies in which the end stage is excessive tissue remodeling, and provide unique and more pathology-specific biochemical markers. PMID:23046407

Evaluation of Techniques for Reducing In-Use Automotive Fuel Consumption

DOT National Transportation Integrated Search

1981-04-01

This report presents an assessment of proposed techniques for reducing fuel consumption in the in-use light duty road vehicle fleet. Three general classes of techniques are treated: (1) modification of vehicles, (2) modification of traffic flow, and ...

Spectral response modification of TiO₂ MSM photodetector with an LSPR filter.

PubMed

Calışkan, Deniz; Bütün, Bayram; Ozcan, Sadan; Ozbay, Ekmel

2014-06-16

We fabricated UVB filtered TiO₂ MSM photodetectors by the localized surface plasmon resonance effect. A plasmonic filter structure was designed using FDTD simulations. Final filter structure was fabricated with Al nano-cylinders with a 70 nm radius 180 nm period on 360 nm SiO₂film. The spectral response of the TiO₂ MSM photodetector was modified and the UVB response was reduced by approx. 60% with an LSPR structure, resulting in a peak responsivity shift of more than 40 nm. To our knowledge, this is the first published result for the spectral response modification of TiO₂ photodetectors with LSPR technique.

Tubulin post-translational modifications in the primitive protist Trichomonas vaginalis.

PubMed

Delgado-Viscogliosi, P; Brugerolle, G; Viscogliosi, E

1996-01-01

Using several specific monoclonal antibodies, we investigated the occurrence and distribution of different post-translationally modified tubulin during interphase and division of the primitive flagellated protist Trichomonas vaginalis. Immunoblotting and immunofluorescence experiments revealed that interphasic microtubular structures of T. vaginalis contained acetylated and glutamylated but non-tyrosinated and non-glycylated [Brugerolle and Adoutte, 1988: Bio Systems 21: 255-268] tubulin. Immunofluorescence studies performed on dividing cells showed that the extranuclear mitotic spindle (or paradesmosis) was acetylated and glutamylated, which contrast with the ephemeral nature of this structure. Newly formed short axostyles also contained acetylated and glutamylated tubulin suggesting that both post-translational modifications might take place very early after assembly of microtubular structures. Our results indicate that acetylation and glutamylation of tubulin appeared early in the history of eukaryotes and could reflect the occurrence of post-translational modifications of tubulin in the primitive eukaryotic cells. These cells probably had a highly ordered cross-linked microtubular cytoskeleton in which microtubules showed a low level of subunit exchange dynamics.

Modulating nanoparticle superlattice structure using proteins with tunable bond distributions

DOE PAGES

McMillan, Janet R.; Brodin, Jeffrey D.; Millan, Jaime A.; ...

2017-01-25

Here, we investigate the use of proteins with tunable DNA modification distributions to modulate nanoparticle superlattice structure. Using Beta-galactosidase (βgal) as a model system, we have employed the orthogonal chemical reactivities of surface amines and thiols to synthesize protein-DNA conjugates with 36 evenly distributed or 8 specifically positioned oligonucleotides. When assembled into crystalline superlattices with AuNPs, we find that the distribution of DNA modifications modulates the favored structure: βgal with uniformly distributed DNA bonding elements results in body-centered cubic crystals, whereas DNA functionalization of cysteines results in AB 2 packing. We probe the role of protein oligonucleotide number and conjugatemore » size on this observation, which revealed the importance of oligonucleotide distribution and number in this observed assembly behavior. These results indicate that proteins with defined DNA-modification patterns are powerful tools to control the nanoparticle superlattices architecture, and establish the importance of oligonucleotide distribution in the assembly behavior of protein-DNA conjugates.« less

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

Eremin, N. N., E-mail: neremin@geol.msu.ru; Grechanovsky, A. E.; Marchenko, E. I.

Semi-empirical and ab initio theoretical investigation of crystal structure geometry, interatomic distances, phase densities and elastic properties for some CaAl{sub 2}O{sub 4} phases under pressures up to 200 GPa was performed. Two independent simulation methods predicted the appearance of a still unknown super-dense CaAl{sub 2}O{sub 4} modification. In this structure, the Al coordination polyhedron might be described as distorted one with seven vertices. Ca atoms were situated inside polyhedra with ten vertices and Ca–O distances from 1.96 to 2.49 Å. It became the densest modification under pressures of 170 GPa (density functional theory prediction) or 150 GPa (semi-empirical prediction). Bothmore » approaches indicated that this super-dense CaAl{sub 2}O{sub 4} modification with a “stuffed α-PbO{sub 2}” type structure could be a probable candidate for mutual accumulation of Ca and Al in the lower mantle. The existence of this phase can be verified experimentally using high pressure techniques.« less

Control of peptide nanotube diameter by chemical modifications of an aromatic residue involved in a single close contact

PubMed Central

Tarabout, Christophe; Roux, Stéphane; Gobeaux, Frédéric; Fay, Nicolas; Pouget, Emilie; Meriadec, Cristelle; Ligeti, Melinda; Thomas, Daniel; IJsselstijn, Maarten; Besselievre, François; Buisson, David-Alexandre; Verbavatz, Jean-Marc; Petitjean, Michel; Valéry, Céline; Perrin, Lionel; Rousseau, Bernard; Artzner, Franck; Paternostre, Maité; Cintrat, Jean-Christophe

2011-01-01

Supramolecular self-assembly is an attractive pathway for bottom-up synthesis of novel nanomaterials. In particular, this approach allows the spontaneous formation of structures of well-defined shapes and monodisperse characteristic sizes. Because nanotechnology mainly relies on size-dependent physical phenomena, the control of monodispersity is required, but the possibility of tuning the size is also essential. For self-assembling systems, shape, size, and monodispersity are mainly settled by the chemical structure of the building block. Attempts to change the size notably by chemical modification usually end up with the loss of self-assembly. Here, we generated a library of 17 peptides forming nanotubes of monodisperse diameter ranging from 10 to 36 nm. A structural model taking into account close contacts explains how a modification of a few Å of a single aromatic residue induces a fourfold increase in nanotube diameter. The application of such a strategy is demonstrated by the formation of silica nanotubes of various diameters. PMID:21518895

33 CFR 238.4 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., containing such structures as residences, public and commercial buildings, and industrial sites. (b) Flood... major storms and snowmelt. They include structural and other engineering modifications to natural...

33 CFR 238.4 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., containing such structures as residences, public and commercial buildings, and industrial sites. (b) Flood... major storms and snowmelt. They include structural and other engineering modifications to natural...

33 CFR 238.4 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., containing such structures as residences, public and commercial buildings, and industrial sites. (b) Flood... major storms and snowmelt. They include structural and other engineering modifications to natural...

33 CFR 238.4 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., containing such structures as residences, public and commercial buildings, and industrial sites. (b) Flood... major storms and snowmelt. They include structural and other engineering modifications to natural...

33 CFR 238.4 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., containing such structures as residences, public and commercial buildings, and industrial sites. (b) Flood... major storms and snowmelt. They include structural and other engineering modifications to natural...

Histone ubiquitination: a tagging tail unfolds?

PubMed

Jason, Laure J M; Moore, Susan C; Lewis, John D; Lindsey, George; Ausió, Juan

2002-02-01

Despite the fact that histone H2A ubiquitination affects about 10-15% of this histone in most eukaryotic cells, histone ubiquitination is among one of the less-well-characterized post-translational histone modifications. Nevertheless, some important observations have been made in recent years. Whilst several enzymes had been known to ubiquitinate histones in vitro, recent studies in yeast have led to the unequivocal identification of the enzyme responsible for this post-translational modification in this organism. A strong functional co-relation to meiosis and spermiogenesis has also now been well documented, although its participation in other functional aspects of chromatin metabolism, such as transcription or DNA repair, still remains rather speculative and controversial. Because of its nature, histone ubiquitination represents the most bulky structural change to histones and as such it would be expected to exert an important effect on chromatin structure. Past and recent structural studies, however, indicate a surprising lack of effect of (H2A/H2B) ubiquitination on nucleosome architecture and of uH2A on chromatin folding. These results suggest that this modification may serve as a signal for recognition by functionally relevant trans-acting factors and/or operate synergistically in conjunction with other post-translational modifications such as for instance acetylation. Copyright 2002 Wiley Periodicals, Inc.

Structural behavior of the space shuttle SRM Tang-Clevis joint

NASA Technical Reports Server (NTRS)

Greene, W. H.; Knight, N. F., Jr.; Stockwell, A. E.

1986-01-01

The space shuttle Challenger accident investigation focused on the failure of a tang-clevis joint on the right solid rocket motor. The existence of relative motion between the inner arm of the clevis and the O-ring sealing surface on the tang has been identified as a potential contributor to this failure. This motion can cause the O-rings to become unseated and therefore lose their sealing capability. Finite element structural analyses have been performed to predict both deflections and stresses in the joint under the primary, pressure loading condition. These analyses have demonstrated the difficulty of accurately predicting the structural behavior of the tang-clevis joint. Stresses in the vicinity of the connecting pins, obtained from elastic analyses, considerably exceed the material yield allowables indicating that inelastic analyses are probably necessary. Two modifications have been proposed to control the relative motion between the inner clevis arm and the tang at the O-ring sealing surface. One modification, referred to as the capture feature, uses additional material on the inside of the tang to restrict motion of the inner clevis arm. The other modification uses external stiffening rings above and below the joint to control the local bending in the shell near the joint. Both of these modifications are shown to be effective in controlling the relative motion in the joint.

Structural behavior of the space shuttle SRM tang-clevis joint

NASA Technical Reports Server (NTRS)

Greene, William H.; Knight, Norman F., Jr.; Stockwell, Alan E.

1988-01-01

The space shuttle Challenger accident investigation focused on the failure of a tang-clevis joint on the right solid rocket motor. The existence of relative motion between the inner arm of the clevis and the O-ring sealing surface on the tang has been identified as a potential contributor to this failure. This motion can cause the O-rings to become unseated and therefore lose their sealing capability. Finite element structural analyses have been performed to predict both deflections and stresses in the joint under the primary, pressure loading condition. These analyses have demonstrated the difficulty of accurately predicting the structural behavior of the tang-clevis joint. Stresses in the vicinity of the connecting pins, obtained from elastic analyses, considerably exceed the material yield allowables indicating that inelastic analyses are probably necessary. Two modifications have been proposed to control the relative motion between the inner clevis arm and the tang at the O-ring sealing surface. One modification, referred to as the capture feature, uses additional material on the inside of the tang to restrict motion of the inner clevis arm. The other modification uses external stiffening rings above and below the joint to control the local bending in the shell near the joint. Both of these modifications are shown to be effective in controlling the relative motion in the joint.

Hydraulic modeling of stream channels and structures in Harbor and Crow Hollow Brooks, Meriden, Connecticut

USGS Publications Warehouse

Weiss, Lawrence A.; Sears, Michael P.; Cervione, Michael A.

1994-01-01

Effects of urbanization have increased the frequency and size of floods along certain reaches of Harbor Brook and Crow Hollow Brook in Meriden, Conn. A floodprofile-modeling study was conducted to model the effects of selected channel and structural modifications on flood elevations and inundated areas. The study covered the reach of Harbor Brook downstream from Interstate 691 and the reach of Crow Hollow Brook downstream from Johnson Avenue. Proposed modifications, which include changes to bank heights, channel geometry, structural geometry, and streambed armoring on Harbor Brook and changes to bank heights on Crow Hollow Brook, significantly lower flood elevations. Results of the modeling indicate a significant reduction of flood elevations for the 10-year, 25-year, 35-year, 50-year, and 100-year flood frequencies using proposed modifications to (1 ) bank heights between Harbor Brook Towers and Interstate 691 on Harbor Brook, and between Centennial Avenue and Johnson Avenue on Crow Hollow Brook; (2) channel geometry between Coe Avenue and Interstate 69 1 on Harbor Brook; (3) bridge and culvert opening geometry between Harbor Brook Towers and Interstate 691 on Harbor Brook; and (4) channel streambed armoring between Harbor Brook Towers and Interstate 691 on Harbor Brook. The proposed modifications were developed without consideration of cost-benefit ratios.

Visual soil evaluation - future research requirements

NASA Astrophysics Data System (ADS)

Emmet-Booth, Jeremy; Forristal, Dermot; Fenton, Owen; Ball, Bruce; Holden, Nick

2017-04-01

A review of Visual Soil Evaluation (VSE) techniques (Emmet-Booth et al., 2016) highlighted their established utility for soil quality assessment, though some limitations were identified; (1) The examination of aggregate size, visible intra-porosity and shape forms a key assessment criterion in almost all methods, thus limiting evaluation to structural form. The addition of criteria that holistically examine structure may be desirable. For example, structural stability can be indicated using dispersion tests or examining soil surface crusting, while the assessment of soil colour may indirectly indicate soil organic matter content, a contributor to stability. Organic matter assessment may also indicate structural resilience, along with rooting, earthworm numbers or shrinkage cracking. (2) Soil texture may influence results or impeded method deployment. Modification of procedures to account for extreme texture variation is desirable. For example, evidence of compaction in sandy or single grain soils greatly differs to that in clayey soils. Some procedures incorporate separate classification systems or adjust deployment based on texture. (3) Research into impacts of soil moisture content on VSE evaluation criteria is required. Criteria such as rupture resistance and shape may be affected by moisture content. It is generally recommended that methods are deployed on moist soils and quantification of influences of moisture variation on results is necessary. (4) Robust sampling strategies for method deployment are required. Dealing with spatial variation differs between methods, but where methods can be deployed over large areas, clear instruction on sampling is required. Additionally, as emphasis has been placed on the agricultural production of soil, so the ability of VSE for exploring structural quality in terms of carbon storage, water purification and biodiversity support also requires research. References Emmet-Booth, J.P., Forristal. P.D., Fenton, O., Ball, B.C. & Holden, N.M. 2016. A review of visual soil evaluation techniques for soil structure. Soil Use and Management, 32, 623-634.

78 FR 42720 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-17

... airplane reaching its limit of validity (LOV) of the engineering data that support the established structural maintenance program. For certain airplanes, this proposed AD would require modification of the web... would require an inspection for cracks in the web, and repair or modification as applicable. We are...

78 FR 65185 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-31

... airplane reaching its limit of validity (LOV) of the engineering data that support the established structural maintenance program. This AD requires, for certain airplanes, a modification of the web of the... cracks in the web, and repair or modification as applicable. We are issuing this AD to prevent cracking...

Feasibility study of modifications to BQM-34E drone for NASA research applications

NASA Technical Reports Server (NTRS)

James, H. A.

1972-01-01

The feasibility of modifying an existing supersonic drone into a free-flight research vehicle is examined. Appropriate structural and control system modifications, reliability and operational considerations, and ROM costs indicate that the BQM-34E drone is indeed suitable as a NASA research vehicle.

Outstanding effects on antithrombin activity of modified TBA diastereomers containing an optically pure acyclic nucleotide analogue.

PubMed

Scuotto, M; Persico, M; Bucci, M; Vellecco, V; Borbone, N; Morelli, E; Oliviero, G; Novellino, E; Piccialli, G; Cirino, G; Varra, M; Fattorusso, C; Mayol, L

2014-07-28

Herein, we report optically pure modified acyclic nucleosides as ideal probes for aptamer modification. These new monomers offer unique advantages in exploring the role played in thrombin inhibition by a single residue modification at key positions of the TBA structure.

Using Chromatin Immunoprecipitation in Toxicology: A Step-by-Step Guide to Increasing Efficiency, Reducing Variability, and Expanding Applications

EPA Science Inventory

Histone modifications work in concert with DNA methylation to regulate cellular structure, function, and the response to environmental stimuli. More than 130 unique histone modifications have been described to date and chromatin immunoprecipitation (ChIP) allows for the explorat...

Celebrating wobble decoding: Half a century and still much is new.

PubMed

Agris, Paul F; Eruysal, Emily R; Narendran, Amithi; Väre, Ville Y P; Vangaveti, Sweta; Ranganathan, Srivathsan V

2017-08-16

A simple post-transcriptional modification of tRNA, deamination of adenosine to inosine at the first, or wobble, position of the anticodon, inspired Francis Crick's Wobble Hypothesis 50 years ago. Many more naturally-occurring modifications have been elucidated and continue to be discovered. The post-transcriptional modifications of tRNA's anticodon domain are the most diverse and chemically complex of any RNA modifications. Their contribution with regards to chemistry, structure and dynamics reveal individual and combined effects on tRNA function in recognition of cognate and wobble codons. As forecast by the Modified Wobble Hypothesis 25 years ago, some individual modifications at tRNA's wobble position have evolved to restrict codon recognition whereas others expand the tRNA's ability to read as many as four synonymous codons. Here, we review tRNA wobble codon recognition using specific examples of simple and complex modification chemistries that alter tRNA function. Understanding natural modifications has inspired evolutionary insights and possible innovation in protein synthesis.

Comparative study of ferromagnetic and non-ferromagnetic modifications of TDAE-C60

NASA Astrophysics Data System (ADS)

Arčon, D.; Blinc, R.; Cevc, P.; Omerzu, A.; Mihailovič, D.

1999-09-01

The magnetic properties of two different modifications of TDAE-C60 have been studied with the ESR and 1H NMR. Well-annealed single crystals display a transition to a ferromagnetically ordered state as confirmed by the observation of the ferromagnetic resonance. On the other hand the magnetic ground state of the non-ferromagnetic modification is consistent with the singlet ground state. The gap between the singlet and low laying triplet excited state opens below 11 K and reaches about 15 K at 5 K. A possible structural differences and their impact on the observed magnetic properties of the two modifications are discussed.

2'-O-[2-[2-(N,N-Dimethylamino)ethoxy]ethyl] Modified Antisense Oligonucleotides: Symbiosis of Charge Interaction Factors and Stereoelectronic Effects

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

Prhavc, M.; Prakash, T.P.; Minasov, G.

Oligonucleotides with a novel, 2'-O-[2-[2-(N,N-dimethylamino)ethoxy]ethyl] (2'-O-DMAEOE) modification have been synthesized. This modification, a cationic analogue of the 2'-O-(2-methoxyethyl) (2'-O-MOE) modification, exhibits high binding affinity to target RNA (but not to DNA) and exceptional resistance to nuclease degradation. Analysis of the crystal structure of a self-complementary oligonucleotide containing a single 2'-O-DMAEOE modification explains the importance of charge factors and gauche effects on the observed antisense properties. 2'-O-DMAEOE modified oligonucleotides are ideal candidates for antisense drugs.

Quantitative PCR measurement of tRNA 2-methylthio modification for assessing type 2 diabetes risk.

PubMed

Xie, Peiyu; Wei, Fan-Yan; Hirata, Shoji; Kaitsuka, Taku; Suzuki, Tsutomu; Suzuki, Takeo; Tomizawa, Kazuhito

2013-11-01

Genetic variants in the human CDKAL1 (CDK5 regulatory subunit associated protein 1-like 1) gene have been associated with reduced insulin secretion and type 2 diabetes (T2D). CDKAL1 is a methylthiotransferase that catalyzes 2-methylthio (ms(2)) modification of the adenine at position 37 (A37) of cytoplasmic tRNA(Lys)(UUU). We investigated the ms(2)-modification level of tRNA(Lys)(UUU) as a direct readout of CDKAL1 enzyme activity in human samples. We developed a quantitative PCR (qPCR)-based method to measure ms(2) modification. tRNA(Lys)(UUU) was reverse-transcribed with 2 unique primers: Reverse primer r1 was designed to anneal to the middle of this tRNA, including the nucleotide at A37, and reverse primer r2 was designed to anneal to the region downstream (3') of A37. Subsequent qPCR was performed to detect the corresponding transcribed cDNAs. The efficiency of reverse transcription of tRNA(Lys)(UUU) was ms(2)-modification dependent. The relative difference in threshold cycle number obtained with the r1 or r2 primer yielded the ms(2)-modification level in tRNA(Lys)(UUU) precisely as predicted by an original mathematical model. The method was capable of measuring ms(2)-modification levels in tRNA(Lys)(UUU) in total RNA isolated from human peripheral blood samples, revealing that the ms(2)-modification rate in tRNA(Lys)(UUU) was decreased in individuals carrying the CDKAL1 genotype associated with T2D. In addition, the ms(2)-modification level was correlated with insulin secretion. The results point to the critical role of ms(2) modification in T2D and to a potential clinical use of a simple and high-throughput method for assessing T2D risk.

14 CFR 152.605 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) Consideration of using alternative, renewable energy sources. Major building modification means modification of... AIRPORT AID PROGRAM Energy Conservation in Airport Aid Program § 152.605 Definitions. As used in this... the program, which will exceed $200,000 in construction cost. Energy assessment means an analysis of...

45 CFR 641.19 - Modification of environmental documents.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 3 2013-10-01 2013-10-01 false Modification of environmental documents. 641.19 Section 641.19 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION ENVIRONMENTAL ASSESSMENT PROCEDURES FOR PROPOSED NATIONAL SCIENCE FOUNDATION ACTIONS IN ANTARCTICA...

45 CFR 641.19 - Modification of environmental documents.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 45 Public Welfare 3 2012-10-01 2012-10-01 false Modification of environmental documents. 641.19 Section 641.19 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION ENVIRONMENTAL ASSESSMENT PROCEDURES FOR PROPOSED NATIONAL SCIENCE FOUNDATION ACTIONS IN ANTARCTICA...

45 CFR 641.19 - Modification of environmental documents.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 3 2010-10-01 2010-10-01 false Modification of environmental documents. 641.19 Section 641.19 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION ENVIRONMENTAL ASSESSMENT PROCEDURES FOR PROPOSED NATIONAL SCIENCE FOUNDATION ACTIONS IN ANTARCTICA...

45 CFR 641.19 - Modification of environmental documents.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 3 2011-10-01 2011-10-01 false Modification of environmental documents. 641.19 Section 641.19 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION ENVIRONMENTAL ASSESSMENT PROCEDURES FOR PROPOSED NATIONAL SCIENCE FOUNDATION ACTIONS IN ANTARCTICA...

45 CFR 641.19 - Modification of environmental documents.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 3 2014-10-01 2014-10-01 false Modification of environmental documents. 641.19 Section 641.19 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION ENVIRONMENTAL ASSESSMENT PROCEDURES FOR PROPOSED NATIONAL SCIENCE FOUNDATION ACTIONS IN ANTARCTICA...

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

Kulchin, Yu N; Mayor, A Yu; Proschenko, D Yu

Specific features of modification of a new photorecording material based on PMMA doped with 2,2-difluoro-4-(9-antracyl)-6-methyl-1,3,2-dioxaborine are studied. The recording of the filament distribution in the studied material occurs at the expense of two-photon photochemical processes. The three-dimensional modification of the material is achieved in the filamentation regime without supercontinuum generation. It is possible to order the volume structure by preliminary photo-modification of the near-surface layer of the material. (extreme light fields and their applications)

Post-translational modifications in secreted peptide hormones in plants.

PubMed

Matsubayashi, Yoshikatsu

2011-01-01

More than a dozen secreted peptides are now recognized as important hormones that coordinate and specify cellular functions in plants. Recent evidence has shown that secreted peptide hormones often undergo post-translational modification and proteolytic processing, which are critical for their function. Such 'small post-translationally modified peptide hormones' constitute one of the largest groups of peptide hormones in plants. This short review highlights recent progress in research on post-translationally modified peptide hormones, with particular emphasis on their structural characteristics and modification mechanisms.

Habit modification of potassium acid phthalate (KAP) single crystals by impurities

NASA Astrophysics Data System (ADS)

Murugakoothan, P.; Mohan Kumar, R.; Ushasree, P. M.; Jayavel, R.; Dhanasekaran, R.; Ramasamy, P.

1999-12-01

Nonlinear optical materials potassium dihydrogen phosphate (KDP), urea and L-arginine phosphate (LAP)-doped KAP crystals were grown by the slow cooling method. The LAP-doped crystals show pronounced habit modification compared to KDP and urea doping. The effect of these impurities on growth kinetics, surface morphology, habit modification, structure, optical and mechanical properties have been studied. Among the three impurities, urea doping yields high mechanical stability and optical transmission and for KDP and LAP doping there is a decrease in optical transmission.

Controlling the potential hazards of government-sponsored technology. [such as weather modification and the supersonic transports

NASA Technical Reports Server (NTRS)

Wollan, M. J.

1975-01-01

The ability was examined of governmental agencies to adequately assess technological programs or projects to which they are committed. The hazards of government-sponsored activities are discussed; these include weather modification, supersonic transport noise, and the value conflicts involved in the fluoridation controversy. These three case studies indicate that the Federal vested interests in the continuation of its technological programs limit its ability to provide adequate technology assessment.

Effects of structural modifications on the metal binding, anti-amyloid activity, and cholinesterase inhibitory activity of chalcones.

PubMed

Fosso, Marina Y; LeVine, Harry; Green, Keith D; Tsodikov, Oleg V; Garneau-Tsodikova, Sylvie

2015-09-28

As the number of individuals affected with Alzheimer's disease (AD) increases and the availability of drugs for AD treatment remains limited, the need to develop effective therapeutics for AD becomes more and more pressing. Strategies currently pursued include inhibiting acetylcholinesterase (AChE) and targeting amyloid-β (Aβ) peptides and metal-Aβ complexes. This work presents the design, synthesis, and biochemical evaluation of a series of chalcones, and assesses the relationship between their structures and their ability to bind metal ions and/or Aβ species, and inhibit AChE/BChE activity. Several chalcones were found to exhibit potent disaggregation of pre-formed N-biotinyl Aβ1-42 (bioAβ42) aggregates in vitro in the absence and presence of Cu(2+)/Zn(2+), while others were effective at inhibiting the action of AChE.

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

Avdontceva, Margarita S.; Zolotarev, Andrey A.; Krivovichev, Sergey V., E-mail: s.krivovichev@spbu.ru

High-temperature phase transition of synthetic kogarkoite, Na{sub 3}SO{sub 4}F, has been studied by high-temperature X-ray powder and single-crystal diffraction. The temperature of the phase transition can be estimated as 112.5±12.5 °C. The low-temperature phase, α-Na{sub 3}SO{sub 4}F, at 293 K, is monoclinic, P2{sub 1}/m, a=18.065(3), b=6.958(1), c=11.446(1) Å, β=107.711(1)°, Z=12. The structure contains thirteen symmetrically independent Na sites with coordination numbers varying from 6 to 8, and six independent S sites. The high-temperature β-phase at 423 K is rhombohedral, R-3m, a=6.94(1), c=24.58(4) Å, Z=9. The crystal structure of both polymorphs of Na{sub 3}SO{sub 4}F can be described as a 9Rmore » antiperovskite polytype based upon triplets of face-sharing [FNa{sub 6}] octahedra linked into a three-dimensional framework by sharing corners. In the α-modification, the SO{sub 4} tetrahedra are completely ordered and located in the framework cavities. In the β-modification, there are only two symmetrically independent Na atoms in the structure. The main difference between the structures of the α- and β-phases is the degree of ordering of the SO{sub 4} tetrahedra: in the α-modification, they are completely ordered, whereas, in the β-modification, the complete disorder is observed, which is manifested in a number of low-occupied O sites around fully occupied S sites. The phase transition is therefore has an order–disorder character and is associated with the decrease of structural complexity measured as an information content per unit cell [577.528 bits for the low- (α) and 154.830 bits for the high- (β) temperature modifications]. - Graphical abstract: High-temperature phase transition of synthetic kogarkoite, Na{sub 3}SO{sub 4}F, revealed the existence of the monoclinic-to-rhombohedral phase transition at 112.5±12.5 °C. The phase transition has an order–disorder character and is associated with the decrease of structural complexity. - Highlights: • Phase transition in Na{sub 3}SO{sub 4}F (kogarkoite) has an order–disorder character. • Antiperovskite framework of F-centered octahedra has a high stability. • Information-based structural complexity decreases across the phase transition.« less

Using Chromatin Immunoprecipitation in Toxicology: A Step-by-Step Guide to Increasing Efficiency, Reducing Variability, and Expanding Applications.

PubMed

McCullough, Shaun D; On, Doan M; Bowers, Emma C

2017-05-02

Histone modifications work in concert with DNA methylation to regulate cellular structure, function, and response to environmental stimuli. More than 130 unique histone modifications have been described to date, and chromatin immunoprecipitation (ChIP) allows for the exploration of their associations with the regulatory regions of target genes and other DNA/chromatin-associated proteins across the genome. Many variations of ChIP have been developed in the 30 years since its earliest version came into use, which makes it challenging for users to integrate the procedure into their research programs. Furthermore, the differences in ChIP protocols can confound efforts to increase reproducibility across studies. The streamlined ChIP procedure presented here can be readily applied to samples from a wide range of in vitro studies (cell lines and primary cells) and clinical samples (peripheral leukocytes) in toxicology. We also provide detailed guidance on the optimization of critical protocol parameters, such as chromatin fixation, fragmentation, and immunoprecipitation, to increase efficiency and improve reproducibility. Expanding toxicoepigenetic studies to more readily include histone modifications will facilitate a more comprehensive understanding of the role of the epigenome in environmental exposure effects and the integration of epigenetic data in mechanistic toxicology, adverse outcome pathways, and risk assessment. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Engineered/designer biochar for contaminant removal/immobilization from soil and water: Potential and implication of biochar modification.

PubMed

Rajapaksha, Anushka Upamali; Chen, Season S; Tsang, Daniel C W; Zhang, Ming; Vithanage, Meththika; Mandal, Sanchita; Gao, Bin; Bolan, Nanthi S; Ok, Yong Sik

2016-04-01

The use of biochar has been suggested as a means of remediating contaminated soil and water. The practical applications of conventional biochar for contaminant immobilization and removal however need further improvements. Hence, recent attention has focused on modification of biochar with novel structures and surface properties in order to improve its remediation efficacy and environmental benefits. Engineered/designer biochars are commonly used terms to indicate application-oriented, outcome-based biochar modification or synthesis. In recent years, biochar modifications involving various methods such as, acid treatment, base treatment, amination, surfactant modification, impregnation of mineral sorbents, steam activation and magnetic modification have been widely studied. This review summarizes and evaluates biochar modification methods, corresponding mechanisms, and their benefits for contaminant management in soil and water. Applicability and performance of modification methods depend on the type of contaminants (i.e., inorganic/organic, anionic/cationic, hydrophilic/hydrophobic, polar/non-polar), environmental conditions, remediation goals, and land use purpose. In general, modification to produce engineered/designer biochar is likely to enhance the sorption capacity of biochar and its potential applications for environmental remediation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clients' experiences of a community based lifestyle modification program: a qualitative study.

PubMed

Chan, Ruth S M; Lok, Kris Y W; Sea, Mandy M M; Woo, Jean

2009-10-01

There is little information about how clients attending lifestyle modification programs view the outcomes. This qualitative study examined the clients' experience of a community based lifestyle modification program in Hong Kong. Semi-structured interviews were conducted with 25 clients attending the program. Clients perceived the program had positive impacts on their health and nutrition knowledge. They experienced frustration, negative emotion, lack of motivation, and pressure from others during the program. Working environment and lack of healthy food choices in restaurants were the major perceived environmental barriers for lifestyle modification. Clients valued nutritionists' capability of providing professional information and psychological support in the program. Our results suggest that nutritionist's capability of providing quality consultations and patient-centered care are important for empowering clients achieve lifestyle modification.

High-resolution structure of the Escherichia coli ribosome

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

Noeske, Jonas; Wasserman, Michael R.; Terry, Daniel S.

Protein synthesis by the ribosome is highly dependent on the ionic conditions in the cellular environment, but the roles of ribosome solvation remain poorly understood. Moreover, the function of modifications to ribosomal RNA and ribosomal proteins are unclear. Here we present the structure of the Escherichia coli 70S ribosome to 2.4 Å resolution. The structure reveals details of the ribosomal subunit interface that are conserved in all domains of life, and suggest how solvation contributes to ribosome integrity and function. The structure also suggests how the conformation of ribosomal protein uS12 likely impacts its contribution to messenger RNA decoding. Inmore » conclusion, this structure helps to explain the phylogenetic conservation of key elements of the ribosome, including posttranscriptional and posttranslational modifications and should serve as a basis for future antibiotic development.« less

High-resolution structure of the Escherichia coli ribosome

DOE PAGES

Noeske, Jonas; Wasserman, Michael R.; Terry, Daniel S.; ...

2015-03-16

Protein synthesis by the ribosome is highly dependent on the ionic conditions in the cellular environment, but the roles of ribosome solvation remain poorly understood. Moreover, the function of modifications to ribosomal RNA and ribosomal proteins are unclear. Here we present the structure of the Escherichia coli 70S ribosome to 2.4 Å resolution. The structure reveals details of the ribosomal subunit interface that are conserved in all domains of life, and suggest how solvation contributes to ribosome integrity and function. The structure also suggests how the conformation of ribosomal protein uS12 likely impacts its contribution to messenger RNA decoding. Inmore » conclusion, this structure helps to explain the phylogenetic conservation of key elements of the ribosome, including posttranscriptional and posttranslational modifications and should serve as a basis for future antibiotic development.« less

Compositional and structural analysis of nitrogen incorporated and ion implanted diamond thin films

NASA Astrophysics Data System (ADS)

Garratt, Elias James

Significant progress in area of nano-structured thin film systems has taken place in recent decades. In particular, diamond thin film systems are being widely studied for their wear resistant, optical and electronic properties. Of the various methods researchers use to modify the structure of such films, three techniques in particular are of interest due to their versatility: modification of the growth atmosphere, growth on metalized substrates, providing an interfacial layer, and modification through post-growth ion implantation. The aim of this study is to investigate the effects each has to the structure and composition of elements. Different techniques are applied in each section; nitrogen gas dilution in a microwave plasma CVD system, diamond deposition on a metal interfacial layer and ion implantation in thin nanocrystalline diamond film. The forms of nanocrystalline diamond film resulting from such modifications are investigated using advanced spectroscopic and spectrometric techniques, as well as mechanical testing and surface mapping. The impact of these characterizations will provide valuable perspective to researchers in materials science. Understanding the changes to the structure and properties of this class of thin films, which can be induced through various mechanisms, will allow future researchers to refine these films towards technological applications in areas of hard coatings, electronics and photonics.

Acclimation of isoprene emission and photosynthesis to growth temperature in hybrid aspen: resolving structural and physiological controls

PubMed Central

Rasulov, Bahtijor; Bichele, Irina; Hüve, Katja; Vislap, Vivian; Niinemets, Ülo

2018-01-01

Acclimation of foliage to growth temperature involves both structural and physiological modifications, but the relative importance of these two mechanisms of acclimation is poorly known, especially for isoprene emission responses. We grew hybrid aspen (Populus tremula x P. tremuloides) under control (day/night temperature of 25/20 °C) and high temperature conditions (35/27 °C) to gain insight into the structural and physiological acclimation controls. Growth at high temperature resulted in larger and thinner leaves with smaller and more densely packed chloroplasts and with lower leaf dry mass per area (MA). High growth temperature also led to lower photosynthetic and respiration rates, isoprene emission rate and leaf pigment content and isoprene substrate dimethylallyl diphosphate pool size per unit area, but to greater stomatal conductance. However, the declining characteristics were similar when expressed per unit dry mass, indicating that the area-based differences were primarily driven by MA. Acclimation to high temperature further increased heat stability of photosynthesis, and increased activation energies for isoprene emission and isoprene synthase rate constant. This study demonstrates that temperature acclimation of photosynthetic and isoprene emission characteristics per unit leaf area was primarily driven by structural modifications, and we argue that future studies investigating acclimation to growth temperature must consider structural modifications. PMID:25158785

Characterization of Chlamydomonas Ribulose-1,5-bisphosphate carboxylase/oxygenase variants mutated at residues that are post-translationally modified.

PubMed

Rasineni, Girish Kumar; Loh, Pek Chin; Lim, Boon Hoe

2017-02-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the chloroplast enzyme that fixes CO 2 in photosynthesis, but the enzyme also fixes O 2 , which leads to the wasteful photorespiratory pathway. If we better understand the structure-function relationship of the enzyme, we might be able to engineer improvements. When the crystal structure of Chlamydomonas Rubisco was solved, four new posttranslational modifications were observed which are not present in other species. The modifications were 4-hydroxylation of the conserved Pro-104 and 151 residues, and S-methylation of the variable Cys-256 and 369 residues, which are Phe-256 and Val-369 in land plants. Because the modifications were only observed in Chlamydomonas Rubisco, they might account for the differences in kinetic properties between the algal and plant enzymes. Site-directed mutagenesis and chloroplast transformation have been used to test the essentiality of these modifications by replacing each of the residues with alanine (Ala). Biochemical analyses were done to determine the specificity factors and kinetic constants. Replacing the modified-residues in Chlamydomonas Rubisco affected the enzyme's catalytic activity. Substituting hydroxy-Pro-104 and methyl-Cys-256 with alanine influenced Rubisco catalysis. This is the first study on these posttranslationally-modified residues in Rubisco by genetic engineering. As these forms of modifications/regulation are not available in plants, the modified residues could be a means to modulate Rubisco activity. With a better understanding of Rubisco structure-function, we can define targets for improving the enzyme. Copyright © 2016 Elsevier B.V. All rights reserved.

The 1984 NASA/ASEE summer faculty fellowship program

NASA Technical Reports Server (NTRS)

1984-01-01

The assessment of forest productivity and associated nitrogen flux in a number of conifer ecosystems is described. As a base line study of acid precipitation in the Sierra Nevada, involved is the extraction and integration of a number of data planes describing the terrain, soils, lithology, vegetation cover and structure, and microclimate of the region. The development of automated techniques to extract topographic networks (stream canyons and ridge lines) for use as a landscrape skeleton to organize and integrate data sets into an efficient geographical information system is examined. The software is written in both FORTRAN and C, and is portable to a number of different computer environments with minimal modification.

World petroleum assessment 2000; compiled PowerPoint slides

USGS Publications Warehouse

Ahlbrandt, Thomas S.

2001-01-01

The slides in this compilation have been produced for a number of presentations on the World Petroleum Assessment 20000. Many of the figures are taken directly form the publication "U.S. Geological Survey World Petroleum Assessment 2000" - Description and Results: USGS Digital Data Series DDS-60, 2000. Some of the slides are modifications of figures from DDS-60, some are new descriptive slides, and a few are new slides. Several of the slides appear to be duplicates, but in fact are slight modifications for format or content from the same image. Forty-one people participated in this effort as part of the World Energy Assessment Team. The full list of contributors is given ion DDS-60. 

Characterization of IXINITY® (Trenonacog Alfa), a Recombinant Factor IX with Primary Sequence Corresponding to the Threonine-148 Polymorph

PubMed Central

Monroe, Dougald M.; Jenny, Richard J.; Van Cott, Kevin E.; Saward, Laura L.

2016-01-01

The goal of these studies was to extensively characterize the first recombinant FIX therapeutic corresponding to the threonine-148 (Thr-148) polymorph, IXINITY (trenonacog alfa [coagulation factor IX (recombinant)]). Gel electrophoresis, circular dichroism, and gel filtration were used to determine purity and confirm structure. Chromatographic and mass spectrometry techniques were used to identify and quantify posttranslational modifications. Activity was assessed as the ability to activate factor X (FX) both with and without factor VIIIa (FVIIIa) and in a standard clotting assay. All results were consistent across multiple lots. Trenonacog alfa migrated as a single band on Coomassie-stained gels; activity assays were normal and showed <0.002 IU of activated factor IX (FIXa) per IU of FIX. The molecule has >97%  γ-carboxylation and underwent the appropriate structural change upon binding calcium ions. Trenonacog alfa was activated normally with factor XIa (FXIa); once activated it bound to FVIIIa and FXa. When activated to FIXa, it was inhibited efficiently by antithrombin. Glycosylation patterns were similar to plasma-derived FIX with sialic acid content consistent with the literature reports of good pharmacokinetic performance. These studies have shown that trenonacog alfa is a highly pure product with a primary sequence and posttranslational modifications consistent with the common Thr-148 polymorphism of plasma-derived FIX. PMID:26997955

Heparin sodium compliance to USP monograph: structural elucidation of an atypical 2.18 ppm NMR signal.

PubMed

Mourier, Pierre A J; Guichard, Olivier Y; Herman, Fréderic; Viskov, Christian

2012-01-01

The ¹H nuclear magnetic resonance (NMR) acceptance criteria in the new heparin US Pharmacopeia (USP) monograph do not take into account potential structural modifications responsible for any extra signals observed in ¹H NMR spectra, some purified heparins may be non-compliant under the proposed new USP guidelines and incorrectly classified as unsuitable for pharmaceutical use. Heparins from the "ES" source, containing an extra signal at 2.18 ppm, were depolymerized under controlled conditions using heparinases I, II, and III. The oligosaccharides responsible for the 2.18 ppm signal were enriched using orthogonal chromatographic techniques. After multiple purification steps, we obtained an oligosaccharide mixture containing a highly enriched octasaccharide bearing the structural modification responsible for the extra signal. Following heparinase I depolymerization, a pure tetrasaccharide containing the fingerprint structural modification was isolated for full structural determination. Using 1D and 2D ¹H NMR spectroscopy, the structural moiety responsible for the extra signal at 2.18 ppm was identified as an acetyl group on the heparin backbone, most likely resulting from a very minor manufacturing process side reaction that esterifies the uronic acid at position 3. Such analytical peculiarity has always been present in this heparin source and it was used safety over the years. Copyright © 2012 Elsevier B.V. All rights reserved.

SRB Altitude Switch Assembly Wire Harness Failure

NASA Technical Reports Server (NTRS)

Blanche, Jim

2002-01-01

This paper presents an assessment of two wire harness failures that had occurred in Solid Rocket Booster Altitude Switch Assemblies S/N 200001 and S/N 20002. A list of modifications to EDU #4 and modification of qualification units 2000001 and 2000002 are also presented.

Core outcome measures for interventions to prevent or slow the progress of dementia for people living with mild to moderate dementia: Systematic review and consensus recommendations

PubMed Central

Groskreutz, Derek; Grinbergs-Saull, Anna; Howard, Rob; O’Brien, John T.; Mountain, Gail; Woods, Bob; Perneczky, Robert; McCleery, Jenny; Pickett, James; Challis, David; Charlesworth, Georgina; Featherstone, Katie; Jones, Roy; Schneider, Justine; Shepperd, Sasha; Thompson-Coon, Jo; Ballard, Clive; Burns, Alistair; Garrard, Peter; Kehoe, Patrick; Passmore, Peter; Robinson, Louise

2017-01-01

Background There are no disease-modifying treatments for dementia. There is also no consensus on disease modifying outcomes. We aimed to produce the first evidence-based consensus on core outcome measures for trials of disease modification in mild-to-moderate dementia. Methods and findings We defined disease-modification interventions as those aiming to change the underlying pathology. We systematically searched electronic databases and previous systematic reviews for published and ongoing trials of disease-modifying treatments in mild-to-moderate dementia. We included 149/22,918 of the references found; with 81 outcome measures from 125 trials. Trials involved participants with Alzheimer’s disease (AD) alone (n = 111), or AD and mild cognitive impairment (n = 8) and three vascular dementia. We divided outcomes by the domain measured (cognition, activities of daily living, biological markers, neuropsychiatric symptoms, quality of life, global). We calculated the number of trials and of participants using each outcome. We detailed psychometric properties of each outcome. We sought the views of people living with dementia and family carers in three cities through Alzheimer’s society focus groups. Attendees at a consensus conference (experts in dementia research, disease-modification and harmonisation measures) decided on the core set of outcomes using these results. Recommended core outcomes were cognition as the fundamental deficit in dementia and to indicate disease modification, serial structural MRIs. Cognition should be measured by Mini Mental State Examination or Alzheimer's Disease Assessment Scale-Cognitive Subscale. MRIs would be optional for patients. We also made recommendations for measuring important, but non-core domains which may not change despite disease modification. Limitations Most trials were about AD. Specific instruments may be superseded. We searched one database for psychometric properties. Interpretation This is the first review to identify the 81 outcome measures the research community uses for disease-modifying trials in mild-to-moderate dementia. Our recommendations will facilitate designing, comparing and meta-analysing disease modification trials in mild-to-moderate dementia, increasing their value. Trial registration PROSPERO no. CRD42015027346. PMID:28662127

Self-Perception versus Students' Perception of Teachers' Personal Style in College Science and Mathematics Courses

NASA Astrophysics Data System (ADS)

Ben-Chaim, David; Zoller, Uri

2001-06-01

This study focuses on the assessment of students' (N=138) versus their teachers' (N=8) self-perception of the latter's personal style (PS) in the context of science and mathematics teaching in college; it uses the Personal Style Questionnaire and structured interviews for this purpose. The teacher's preferred (the ideal) and the actual personal style profiles thus obtained indicate that there is a good correspondence between the students' and teachers' perceptions concerning the preferred personal style of teachers. It also indicates that the students assess quite adequately the actual PS of their teachers. Regarding the significance of the association between the students' preferred and the teachers' actual PS in College science and mathematics teaching for effective learning, the self-modification of PS by reflective prospective and in-service science teachers is recommended.

Photo-Darkening Kinetics and Structural Anisotropic Modifications in the Chalcogenide Glass Arsenic Trisulfide: a Study of Kinetic X-Ray Absorption Spectroscopy

NASA Astrophysics Data System (ADS)

Lee, Jay Min

1990-08-01

The purpose of the study is to investigate the mechanisms involved with photo-induced atomic structural modifications in the chalcogenide glass As_2 S_3. This glass exhibits the reversible effects of photo-darkening followed by thermal bleaching. We observed the time behavior of photo-induced properties under the influence of linearly polarized band -gap light. In a macroscopic optical investigation, we monitor optical changes in the photo-darkening process, and in a local structural probe we study kinetic (or time -resolved dispersive) x-ray absorption spectroscopy. Our observations center on kinetic phenomena and structural modifications induced by polarized excitation of lone-pair orbitals in the chalcogenide glass. Experimental results include the following observations: (i) The polarity of the optically induced anisotropy is critically dependent on the intensity and the polarization of the band-gap irradiation beam. (ii) The near edge peak height in x-ray absorption spectra shows subtle but sensitive change during the photo-darkening process. (iii) Photon intensity dependent dichroic kinetics reflect a connection between the optically probed macroscopic property and the x-ray probed local anisotropic structure. Analysis of the x-ray absorption results includes a computer simulation of the polarized absorption spectra. These results suggest that specific structural units tend to orient themselves with respect to the photon polarization. A substantial part of the analysis involves a major effort in dealing with the x-ray kinetic data manipulation and the experimental difficulties caused by a synchrotron instability problem. Based on our observations, we propose a possible mechanism for the observed photo-structural modifications. Through a model of computer relaxed photo-darkening kinetics, we support the notion that a twisting of a specific intermediate range order structure is responsible for local directional variations and global network distortions. In the course of this study, we refine knowledge of intermediate range order structural configurations and the bistabilities related to these configurations. The importance of the lone-pair orbital interactions in the chalcogenide glassy network is underscored.

The incorporation of plotting capability into the Unified Subsonic Supersonic Aerodynamic Analysis program, version B

NASA Technical Reports Server (NTRS)

Winter, O. A.

1980-01-01

The B01 version of the United Subsonic Supersonic Aerodynamic Analysis program is the result of numerous modifications and additions made to the B00 version. These modifications and additions affect the program input, its computational options, the code readability, and the overlay structure. The following are described: (1) the revised input; (2) the plotting overlay programs which were also modified, and their associated subroutines, (3) the auxillary files used by the program, the revised output data; and (4) the program overlay structure.

Insights into molecular plasticity in protein complexes from Trm9-Trm112 tRNA modifying enzyme crystal structure.

PubMed

Létoquart, Juliette; van Tran, Nhan; Caroline, Vonny; Aleksandrov, Alexey; Lazar, Noureddine; van Tilbeurgh, Herman; Liger, Dominique; Graille, Marc

2015-12-15

Most of the factors involved in translation (tRNA, rRNA and proteins) are subject to post-transcriptional and post-translational modifications, which participate in the fine-tuning and tight control of ribosome and protein synthesis processes. In eukaryotes, Trm112 acts as an obligate activating platform for at least four methyltransferases (MTase) involved in the modification of 18S rRNA (Bud23), tRNA (Trm9 and Trm11) and translation termination factor eRF1 (Mtq2). Trm112 is then at a nexus between ribosome synthesis and function. Here, we present a structure-function analysis of the Trm9-Trm112 complex, which is involved in the 5-methoxycarbonylmethyluridine (mcm(5)U) modification of the tRNA anticodon wobble position and hence promotes translational fidelity. We also compare the known crystal structures of various Trm112-MTase complexes, highlighting the structural plasticity allowing Trm112 to interact through a very similar mode with its MTase partners, although those share less than 20% sequence identity. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Electronic Structures of Silicene Nanoribbons: Two-Edge-Chemistry Modification and First-Principles Study.

PubMed

Yao, Yin; Liu, Anping; Bai, Jianhui; Zhang, Xuanmei; Wang, Rui

2016-12-01

In this paper, we investigate the structural and electronic properties of zigzag silicene nanoribbons (ZSiNRs) with edge-chemistry modified by H, F, OH, and O, using the ab initio density functional theory method and local spin-density approximation. Three kinds of spin polarized configurations are considered: nonspin polarization (NM), ferromagnetic spin coupling for all electrons (FM), ferromagnetic ordering along each edge, and antiparallel spin orientation between the two edges (AFM). The H, F, and OH groups modified 8-ZSiNRs have the AFM ground state. The directly edge oxidized (O1) ZSiNRs yield the same energy and band structure for NM, FM, and AFM configurations, owning to the same s p (2) hybridization. And replacing the Si atoms on the two edges with O atoms (O2) yields FM ground state. The edge-chemistry-modified ZSiNRs all exhibit metallic band structures. And the modifications introduce special edge state strongly localized at the Si atoms in the edge, except for the O1 form. The modification of the zigzag edges of silicene nanoribbons is a key issue to apply the silicene into the field effect transistors (FETs) and gives more necessity to better understand the experimental findings.

Hospitalization Drug Regimen Changes in Geriatric Patients and Adherence to Modifications by General Practitioners in Primary Care.

PubMed

Rouch, L; Farbos, F; Cool, C; McCambridge, C; Hein, C; Elmalem, S; Rolland, Y; Vellas, B; Cestac, P

2018-01-01

To evaluate the overall rate of adherence by general practitioners (GPs) to treatment modifications suggested at discharge from hospital and to assess the way communication between secondary and primary care could be improved. Observational prospective cohort study. Patients hospitalized from the emergency department to the acute geriatric care unit of a university hospital. 206 subjects with a mean age of 85 years. Changes in drug regimen undertaken during hospitalization were collected with the associated justifications. Adherence at one month by GPs to treatment modifications was assessed as well as modifications implemented in primary care with their rationale in case of non-adherence. Community pharmacists' and GPs' opinions about quality of communication and information transfer at hospital-general practice interface were investigated. 5.5 ± 2.8 drug regimen changes were done per patient during hospitalization. The rate of adherence by GPs to treatment modifications suggested at discharge from hospital was 83%. In most cases, non-adherence by GPs to treatment modifications done during hospitalization was due to dosage adjustments, symptoms resolution but also worsening of symptoms. The last of which was particularly true for psychotropic drugs. All GPs received their patients' discharge letters but the timely dissemination still needs to be improved. Only 6.6% of community pharmacists were informed of treatment modifications done during their patients' hospitalization. Our findings showed a successful rate of adherence by GPs to treatment modifications suggested at discharge from hospital, due to the fact that optimization was done in a collaborative way between geriatricians and hospital pharmacists and that justifications for drug regimen changes were systematically provided in discharge letters. Communication processes at the interface between secondary and primary care, particularly with community pharmacists, must be strengthened to improve seamless care.

Posttranscriptional modification of tRNA in thermophilic archaea (Archaebacteria).

PubMed Central

Edmonds, C G; Crain, P F; Gupta, R; Hashizume, T; Hocart, C H; Kowalak, J A; Pomerantz, S C; Stetter, K O; McCloskey, J A

1991-01-01

Nucleoside modification has been studied in unfractionated tRNA from 11 thermophilic archaea (archaebacteria), including phylogenetically diverse representatives of thermophilic methanogens and sulfur-metabolizing hyperthermophiles which grow optimally in the temperature range of 56 (Thermoplasma acidophilum) to 105 degrees C (Pyrodictium occultum), and for comparison from the most thermophilic bacterium (eubacterium) known, Thermotoga maritima (80 degrees C). Nine nucleosides are found to be unique to the archaea, six of which are structurally novel in being modified both in the base and by methylation in ribose and occur primarily in tRNA from the extreme thermophiles in the Crenarchaeota of the archaeal phylogenetic tree. 2-Thiothymine occurs in tRNA from Thermococcus sp., and constitutes the only known occurrence of the thymine moiety in archaeal RNA, in contrast to its near-ubiquitous presence in tRNA from bacteria and eukarya. A total of 33 modified nucleosides are rigorously characterized in archaeal tRNA in the present study, demonstrating that the structural range of posttranscriptional modifications in archaeal tRNA is more extensive than previously known. From a phylogenetic standpoint, certain tRNA modifications occur in the archaea which are otherwise unique to either the bacterial or eukaryal domain, although the overall patterns of modification are more typical of eukaryotes than bacteria. PMID:1708763

A Co-Precursor Approach Coupled with a Supercritical Modification Method for Constructing Highly Transparent and Superhydrophobic Polymethylsilsesquioxane Aerogels.

PubMed

Lei, Chaoshuai; Li, Junning; Sun, Chencheng; Yang, Hailong; Xia, Tao; Hu, Zijun; Zhang, Yue

2018-03-30

Polymethylsilsesquioxane (PMSQ) aerogels obtained from methyltrimethoxysilane (MTMS) are well-known high-performance porous materials. Highly transparent and hydrophobic PMSQ aerogel would play an important role in transparent vacuum insulation panels. Herein, the co-precursor approach and supercritical modification method were developed to prepare the PMSQ aerogels with high transparency and superhydrophobicity. Firstly, benefiting from the introduction of tetramethoxysilane (TMOS) in the precursor, the pore structure became more uniform and the particle size was decreased. As the TMOS content increased, the light transmittance increased gradually from 54.0% to 81.2%, whereas the contact angle of water droplet decreased from 141° to 99.9°, ascribed to the increase of hydroxyl groups on the skeleton surface. Hence, the supercritical modification method utilizing hexamethyldisilazane was also introduced to enhance the hydrophobic methyl groups on the aerogel's surface. As a result, the obtained aerogels revealed superhydrophobicity with a contact angle of 155°. Meanwhile, the developed surface modification method did not lead to any significant changes in the pore structure resulting in the superhydrophobic aerogel with a high transparency of 77.2%. The proposed co-precursor approach and supercritical modification method provide a new horizon in the fabrication of highly transparent and superhydrophobic PMSQ aerogels.

Methylated nucleosides in tRNA and tRNA methyltransferases

PubMed Central

Hori, Hiroyuki

2014-01-01

To date, more than 90 modified nucleosides have been found in tRNA and the biosynthetic pathways of the majority of tRNA modifications include a methylation step(s). Recent studies of the biosynthetic pathways have demonstrated that the availability of methyl group donors for the methylation in tRNA is important for correct and efficient protein synthesis. In this review, I focus on the methylated nucleosides and tRNA methyltransferases. The primary functions of tRNA methylations are linked to the different steps of protein synthesis, such as the stabilization of tRNA structure, reinforcement of the codon-anticodon interaction, regulation of wobble base pairing, and prevention of frameshift errors. However, beyond these basic functions, recent studies have demonstrated that tRNA methylations are also involved in the RNA quality control system and regulation of tRNA localization in the cell. In a thermophilic eubacterium, tRNA modifications and the modification enzymes form a network that responses to temperature changes. Furthermore, several modifications are involved in genetic diseases, infections, and the immune response. Moreover, structural, biochemical, and bioinformatics studies of tRNA methyltransferases have been clarifying the details of tRNA methyltransferases and have enabled these enzymes to be classified. In the final section, the evolution of modification enzymes is discussed. PMID:24904644

Pore structure modification of diatomite as sulfuric acid catalyst support by high energy electron beam irradiation and hydrothermal treatment

NASA Astrophysics Data System (ADS)

Li, Chong; Zhang, Guilong; Wang, Min; Chen, Jianfeng; Cai, Dongqing; Wu, Zhengyan

2014-08-01

High energy electron beam (HEEB) irradiation and hydrothermal treatment (HT), were applied in order to remove the impurities and enlarge the pore size of diatomite, making diatomite more suitable to be a catalyst support. The results demonstrated that, through thermal, charge, impact and etching effects, HEEB irradiation could make the impurities in the pores of diatomite loose and remove some of them. Then HT could remove rest of them from the pores and contribute significantly to the modification of the pore size distribution of diatomite due to thermal expansion, water swelling and thermolysis effects. Moreover, the pore structure modification improved the properties (BET (Brunauer-Emmett-Teller) specific surface area, bulk density and pore volume) of diatomite and the catalytic efficiency of the catalyst prepared from the treated diatomite.

Enhancing Reactivity in Structural Energetic Materials

NASA Astrophysics Data System (ADS)

Glumac, Nick

2017-06-01

In many structural energetic materials, only a small fraction of the metal oxidizes, and yet this provides a significant boost in the overall energy release of the system. Different methodologies to enhance this reactivity include alloying and geometric modifications of microstructure of the reactive material (RM). In this presentation, we present the results of several years of systematic study of both chemical (alloy) and mechanical (geometry) effects on reactivity for systems with typical charge to case mass ratios. Alloys of aluminum with magnesium and lithium are considered, as these are common alloys in aerospace applications. In terms of geometric modifications, we consider surface texturing, inclusion of dense additives, and inclusion of voids. In all modifications, a measurable influence on output is observed, and this influence is related to the fragment size distribution measured from the observed residue. Support from DTRA is gratefully acknowledged.

Multifunctional structural energy storage composite supercapacitors.

PubMed

Shirshova, Natasha; Qian, Hui; Houllé, Matthieu; Steinke, Joachim H G; Kucernak, Anthony R J; Fontana, Quentin P V; Greenhalgh, Emile S; Bismarck, Alexander; Shaffer, Milo S P

2014-01-01

This paper addresses the challenge of producing multifunctional composites that can simultaneously carry mechanical loads whilst storing (and delivering) electrical energy. The embodiment is a structural supercapacitor built around laminated structural carbon fibre (CF) fabrics. Each cell consists of two modified structural CF fabric electrodes, separated by a structural glass fibre fabric or polymer membrane, infused with a multifunctional polymeric electrolyte. Rather than using conventional activated carbon fibres, structural carbon fibres were treated to produce a mechanically robust, high surface area material, using a variety of methods, including direct etching, carbon nanotube sizing, and carbon nanotube in situ growth. One of the most promising approaches is to integrate a porous bicontinuous monolithic carbon aerogel (CAG) throughout the matrix. This nanostructured matrix both provides a dramatic increase in active surface area of the electrodes, and has the potential to address mechanical issues associated with matrix-dominated failures. The effect of the initial reaction mixture composition is assessed for both the CAG modified carbon fibre electrodes and resulting devices. A low temperature CAG modification of carbon fibres was evaluated using poly(3,4-ethylenedioxythiophene) (PEDOT) to enhance the electrochemical performance. For the multifunctional structural electrolyte, simple crosslinked gels have been replaced with bicontinuous structural epoxy-ionic liquid hybrids that offer a much better balance between the conflicting demands of rigidity and molecular motion. The formation of both aerogel precursors and the multifunctional electrolyte are described, including the influence of key components, and the defining characteristics of the products. Working structural supercapacitor composite prototypes have been produced and characterised electrochemically. The effect of introducing the necessary multifunctional resin on the mechanical properties has also been assessed. Larger scale demonstrators have been produced including a full size car boot/trunk lid.

Commercial processed soy-based food product contains glycated and glycoxidated lunasin proteoforms.

PubMed

Serra, Aida; Gallart-Palau, Xavier; See-Toh, Rachel Su-En; Hemu, Xinya; Tam, James P; Sze, Siu Kwan

2016-05-18

Nutraceuticals have been proposed to exert positive effects on human health and confer protection against many chronic diseases. A major bioactive component of soy-based foods is lunasin peptide, which has potential to exert a major impact on the health of human consumers worldwide, but the biochemical features of dietary lunasin still remain poorly characterized. In this study, lunasin was purified from a soy-based food product via strong anion exchange solid phase extraction and then subjected to top-down mass spectrometry analysis that revealed in detail the molecular diversity of lunasin in processed soybean foods. We detected multiple glycated proteoforms together with potentially toxic advanced glycation end products (AGEs) derived from lunasin. In both cases, modification sites were Lys24 and Lys29 located at the helical region that shows structural homology with a conserved region of chromatin-binding proteins. The identified post-translational modifications may have an important repercussion on lunasin epigenetic regulatory capacity. Taking together, our results demonstrate the importance of proper chemical characterization of commercial processed food products to assess their impact on consumer's health and risk of chronic diseases.

A novel fabrication method of carbon electrodes using 3D printing and chemical modification process.

PubMed

Tian, Pan; Chen, Chaoyang; Hu, Jie; Qi, Jin; Wang, Qianghua; Chen, Jimmy Ching-Ming; Cavanaugh, John; Peng, Yinghong; Cheng, Mark Ming-Cheng

2017-11-23

Three-dimensional (3D) printing is an emerging technique in the field of biomedical engineering and electronics. This paper presents a novel biofabrication method of implantable carbon electrodes with several advantages including fast prototyping, patient-specific and miniaturization without expensive cleanroom. The method combines stereolithography in additive manufacturing and chemical modification processes to fabricate electrically conductive carbon electrodes. The stereolithography allows the structures to be 3D printed with very fine resolution and desired shapes. The resin is then chemically modified to carbon using pyrolysis to enhance electrochemical performance. The electrochemical characteristics of 3D printing carbon electrodes are assessed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The specific capacitance of 3D printing carbon electrodes is much higher than the same sized platinum (Pt) electrode. In-vivo electromyography (EMG) recording, 3D printing carbon electrodes exhibit much higher signal-to-noise ratio (40.63 ± 7.73) than Pt electrodes (14.26 ± 6.83). The proposed biofabrication method is envisioned to enable 3D printing in many emerging applications in biomedical engineering and electronics.

Commercial processed soy-based food product contains glycated and glycoxidated lunasin proteoforms

PubMed Central

Serra, Aida; Gallart-Palau, Xavier; See-Toh, Rachel Su-En; Hemu, Xinya; Tam, James P.; Sze, Siu Kwan

2016-01-01

Nutraceuticals have been proposed to exert positive effects on human health and confer protection against many chronic diseases. A major bioactive component of soy-based foods is lunasin peptide, which has potential to exert a major impact on the health of human consumers worldwide, but the biochemical features of dietary lunasin still remain poorly characterized. In this study, lunasin was purified from a soy-based food product via strong anion exchange solid phase extraction and then subjected to top-down mass spectrometry analysis that revealed in detail the molecular diversity of lunasin in processed soybean foods. We detected multiple glycated proteoforms together with potentially toxic advanced glycation end products (AGEs) derived from lunasin. In both cases, modification sites were Lys24 and Lys29 located at the helical region that shows structural homology with a conserved region of chromatin-binding proteins. The identified post-translational modifications may have an important repercussion on lunasin epigenetic regulatory capacity. Taking together, our results demonstrate the importance of proper chemical characterization of commercial processed food products to assess their impact on consumer’s health and risk of chronic diseases. PMID:27189269

Chemically Patterned Inverse Opal Created by a Selective Photolysis Modification Process.

PubMed

Tian, Tian; Gao, Ning; Gu, Chen; Li, Jian; Wang, Hui; Lan, Yue; Yin, Xianpeng; Li, Guangtao

2015-09-02

Anisotropic photonic crystal materials have long been pursued for their broad applications. A novel method for creating chemically patterned inverse opals is proposed here. The patterning technique is based on selective photolysis of a photolabile polymer together with postmodification on released amine groups. The patterning method allows regioselective modification within an inverse opal structure, taking advantage of selective chemical reaction. Moreover, combined with the unique signal self-reporting feature of the photonic crystal, the fabricated structure is capable of various applications, including gradient photonic bandgap and dynamic chemical patterns. The proposed method provides the ability to extend the structural and chemical complexity of the photonic crystal, as well as its potential applications.

Surface and local electronic structure modification of MgO film using Zn and Fe ion implantation

NASA Astrophysics Data System (ADS)

Singh, Jitendra Pal; Lim, Weon Cheol; Lee, Jihye; Song, Jonghan; Lee, Ik-Jae; Chae, Keun Hwa

2018-02-01

Present work is motivated to investigate the surface and local electronic structure modifications of MgO films implanted with Zn and Fe ions. MgO film was deposited using radio frequency sputtering method. Atomic force microscopy measurements exhibit morphological changes associated with implantation. Implantation of Fe and Zn ions leads to the reduction of co-ordination geometry of Mg2+ ions in host lattice. The effect is dominant at bulk of film rather than surface as the large concentration of implanted ions resides inside bulk. Moreover, the evidences of interaction among implanted ions and oxygen are not being observed using near edge fine structure measurements.

77 FR 65506 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-29

...We propose to supersede an existing airworthiness directive (AD) that applies to certain The Boeing Company Model 757-200 and - 200PF series airplanes. The existing AD currently requires modification of the nacelle strut and wing structure, and repair of any damage found during the modification. Since we issued that AD, a compliance time error involving the optional threshold formula was discovered, which could allow an airplane to exceed the acceptable compliance time for addressing the unsafe condition. This proposed AD would specify a maximum compliance time limit that overrides the optional threshold formula results. We are proposing this AD to prevent fatigue cracking in primary strut structure and consequent reduced structural integrity of the strut.

A practical modification of horizontal line sampling for snag and cavity tree inventory

Treesearch

M. J. Ducey; G. J. Jordan; J. H. Gove; H. T. Valentine

2002-01-01

Snags and cavity trees are important structural features in forests, but they are often sparsely distributed, making efficient inventories problematic. We present a straightforward modification of horizontal line sampling designed to facilitate inventory of these features while remaining compatible with commonly employed sampling methods for the living overstory. The...

Posttranslational nitro-glycative modifications of albumin in Alzheimer's disease: implications in cytotoxicity and amyloid-β peptide aggregation.

PubMed

Ramos-Fernández, Eva; Tajes, Marta; Palomer, Ernest; Ill-Raga, Gerard; Bosch-Morató, Mònica; Guivernau, Biuse; Román-Dégano, Irene; Eraso-Pichot, Abel; Alcolea, Daniel; Fortea, Juan; Nuñez, Laura; Paez, Antonio; Alameda, Francesc; Fernández-Busquets, Xavier; Lleó, Alberto; Elosúa, Roberto; Boada, Mercé; Valverde, Miguel A; Muñoz, Francisco J

2014-01-01

Glycation and nitrotyrosination are pathological posttranslational modifications that make proteins prone to losing their physiological properties. Since both modifications are increased in Alzheimer's disease (AD) due to amyloid-β peptide (Aβ) accumulation, we have studied their effect on albumin, the most abundant protein in cerebrospinal fluid and blood. Brain and plasmatic levels of glycated and nitrated albumin were significantly higher in AD patients than in controls. In vitro turbidometry and electron microscopy analyses demonstrated that glycation and nitrotyrosination promote changes in albumin structure and biochemical properties. Glycated albumin was more resistant to proteolysis and less uptake by hepatoma cells occurred. Glycated albumin also reduced the osmolarity expected for a solution containing native albumin. Both glycation and nitrotyrosination turned albumin cytotoxic in a cell type-dependent manner for cerebral and vascular cells. Finally, of particular relevance to AD, these modified albumins were significantly less effective in avoiding Aβ aggregation than native albumin. In summary, nitrotyrosination and especially glycation alter albumin structural and biochemical properties, and these modifications might contribute for the progression of AD.

Incorporation of post-translational modified amino acids as an approach to increase both chemical and biological diversity of conotoxins and conopeptides.

PubMed

Espiritu, Michael J; Cabalteja, Chino C; Sugai, Christopher K; Bingham, Jon-Paul

2014-01-01

Bioactive peptides from Conus venom contain a natural abundance of post-translational modifications that affect their chemical diversity, structural stability, and neuroactive properties. These modifications have continually presented hurdles in their identification and characterization. Early endeavors in their analysis relied on classical biochemical techniques that have led to the progressive development and use of novel proteomic-based approaches. The critical importance of these post-translationally modified amino acids and their specific assignment cannot be understated, having impact on their folding, pharmacological selectivity, and potency. Such modifications at an amino acid level may also provide additional insight into the advancement of conopeptide drugs in the quest for precise pharmacological targeting. To achieve this end, a concerted effort between the classical and novel approaches is needed to completely elucidate the role of post-translational modifications in conopeptide structure and dynamics. This paper provides a reflection in the advancements observed in dealing with numerous and multiple post-translationally modified amino acids within conotoxins and conopeptides and provides a summary of the current techniques used in their identification.

Friction Stir Processing of Particle Reinforced Composite Materials

PubMed Central

Gan, Yong X.; Solomon, Daniel; Reinbolt, Michael

2010-01-01

The objective of this article is to provide a review of friction stir processing (FSP) technology and its application for microstructure modification of particle reinforced composite materials. The main focus of FSP was on aluminum based alloys and composites. Recently, many researchers have investigated this technology for treating other alloys and materials including stainless steels, magnesium, titanium, and copper. It is shown that FSP technology is very effective in microstructure modification of reinforced metal matrix composite materials. FSP has also been used in the processing and structure modification of polymeric composite materials. Compared with other manufacturing processes, friction stir processing has the advantage of reducing distortion and defects in materials. The layout of this paper is as follows. The friction stir processing technology will be presented first. Then, the application of this technology in manufacturing and structure modification of particle reinforced composite materials will be introduced. Future application of friction stir processing in energy field, for example, for vanadium alloy and composites will be discussed. Finally, the challenges for improving friction stir processing technology will be mentioned.

Structural modifications of polymethacrylates: impact on thermal behavior and release characteristics of glassy solid solutions.

PubMed

Claeys, Bart; De Coen, Ruben; De Geest, Bruno G; de la Rosa, Victor R; Hoogenboom, Richard; Carleer, Robert; Adriaensens, Peter; Remon, Jean Paul; Vervaet, Chris

2013-11-01

Polymethacrylates such as Eudragit® polymers are well established as drug delivery matrix. Here, we synthesize several Eudragit E PO (n-butyl-, dimethylaminoethyl-, methyl-methacrylate-terpolymer) analogues via free radical polymerization. These polymers are processed via hot melt extrusion, followed by injection molding and evaluated as carriers to produce immediate release solid solution tablets. Three chemical modifications increased the glass transition temperature of the polymer: (a) substitution of n-butyl by t-butyl groups, (b) reduction of the dimethylaminoethyl methacrylate (DMAEMA) content, and (c) incorporation of a bulky isobornyl repeating unit. These structural modifications revealed the possibility to increase the mechanical stability of the tablets via altering the polymer Tg without influencing the drug release characteristics and glassy solid solution forming properties. The presence of DMAEMA units proved to be crucial with respect to API/polymer interaction (essential in creating glassy solid solutions) and drug release characteristics. Moreover, these chemical modifications accentuate the need for a more rational design of (methacrylate) polymer matrix excipients for drug formulation via hot melt extrusion and injection molding. Copyright © 2013 Elsevier B.V. All rights reserved.

Laser-Based Surface Modification of Microstructure for Carbon Fiber-Reinforced Plastics

NASA Astrophysics Data System (ADS)

Yang, Wenfeng; Sun, Ting; Cao, Yu; Li, Shaolong; Liu, Chang; Tang, Qingru

2018-05-01

Bonding repair is a powerful feature of carbon fiber-reinforced plastics (CFRP). Based on the theory of interface bonding, the interface adhesion strength and reliability of the CFRP structure will be directly affected by the microscopic features of the CFRP surface, including the microstructure, physical, and chemical characteristics. In this paper, laser-based surface modification was compared to Peel-ply, grinding, and polishing to comparatively evaluate the surface microstructure of CFRP. The surface microstructure, morphology, fiber damage, height and space parameters were investigated by scanning electron microscopy (SEM) and laser confocal microscopy (LCM). Relative to the conventional grinding process, laser modification of the CFRP surface can result in more uniform resin removal and better processing control and repeatability. This decreases the adverse impact of surface fiber fractures and secondary damage. The surface properties were significantly optimized, which has been reflected such things as the obvious improvement of surface roughness, microstructure uniformity, and actual area. The improved surface microstructure based on laser modification is more conducive to interface bonding of CFRP structure repair. This can enhance the interfacial adhesion strength and reliability of repair.

Structural modifications due to interface chemistry at metal-nitride interfaces

DOE PAGES

Yadav, S. K.; Shao, S.; Wang, J.; ...

2015-11-27

Based on accurate first principles density functional theory (DFT) calculations, an unusual phenomenon of interfacial structural modifications, due to the interface chemistry influence is identified at two metal-nitride interfaces with strong metal-nitrogen affinity, Al/TiN {111} and Al/VN {111} interfaces. It is shown that at such interfaces, a faulted stacking structure is energetically preferred on the Al side of the interface. And both intrinsic and extrinsic stacking fault energies in the vicinity Al layers are negligibly small. However, such phenomenon does not occur in Pt/TiN and Pt/VN interfaces because of the weak Pt-N affinity. As a result, corresponding to structural energiesmore » of metal-nitride interfaces, the linear elasticity analysis predicts characteristics of interfacial misfit dislocations at metal-nitride interfaces.« less

Structural modifications due to interface chemistry at metal-nitride interfaces

PubMed Central

Yadav, S. K.; Shao, S.; Wang, J.; Liu, X.-Y.

2015-01-01

Based on accurate first principles density functional theory (DFT) calculations, an unusual phenomenon of interfacial structural modifications, due to the interface chemistry influence is identified at two metal-nitride interfaces with strong metal-nitrogen affinity, Al/TiN {111} and Al/VN {111} interfaces. It is shown that at such interfaces, a faulted stacking structure is energetically preferred on the Al side of the interface. And both intrinsic and extrinsic stacking fault energies in the vicinity Al layers are negligibly small. However, such phenomenon does not occur in Pt/TiN and Pt/VN interfaces because of the weak Pt-N affinity. Corresponding to structural energies of metal-nitride interfaces, the linear elasticity analysis predicts characteristics of interfacial misfit dislocations at metal-nitride interfaces. PMID:26611639

Micro-structural integrity of dental enamel subjected to two tooth whitening regimes.

PubMed

Tanaka, Reina; Shibata, Yo; Manabe, Atsufumi; Miyazaki, Takashi

2010-04-01

Colour modification of tooth enamel has proven successful, but it is unclear how various bleaching applications affect micro-structural integrity of the whitened enamel. To investigate the internal structural integrity of human intact tooth enamel with the application of two commonly used whitening regimes (in-office power bleaching with 35% hydrogen peroxide and home bleaching with 10% carbamide peroxide), evaluations were performed on teeth of identical colour classification. After the bleaching applications, the enamel mineral density was quantified and visualised with micro-computed tomography. The micro-structural differences between the whitened tooth enamel samples were distinctive, though the colour parameter changes within the samples were equivalent. Home bleaching achieved colour modification by demineralisation, whereas in-office bleaching depended on redistribution of the minerals after treatment and subsequent enhanced mineralisation.

The impact of biotechnological advances on the future of US bioenergy

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

Davison, Brian H.; Brandt, Craig C.; Guss, Adam M.

Modern biotechnology has the potential to substantially advance the feasibility, structure, and efficiency of future biofuel supply chains. Advances might be direct or indirect. A direct advance would be improving the efficiency of biochemical conversion processes and feedstock production. Direct advances in processing may involve developing improved enzymes and bacteria to convert lignocellulosic feedstocks to ethanol. Progress in feedstock production could include enhancing crop yields via genetic modification or the selection of specific natural variants and breeds. Other direct results of biotechnology might increase the production of fungible biofuels and bioproducts, which would impact the supply chain. Indirect advances mightmore » include modifications to dedicated bioenergy crops that enable them to grow on marginal lands rather than land needed for food production. This study assesses the feasibility and advantages of near-future (10-year) biotechnological developments for a US biomass-based supply chain for bioenergy production. We assume a simplified supply chain of feedstock, logistics and land use, conversion, and products and utilization. The primary focus is how likely developments in feedstock production and conversion technologies will impact bioenergy and biofuels in the USA; a secondary focus is other innovative uses of biotechnologies in the energy arenas. The assessment addresses near-term biofuels based on starch, sugar, and cellulosic feedstocks and considers some longer-term options, such as oil-crop and algal technologies.« less

The impact of biotechnological advances on the future of US bioenergy

DOE PAGES

Davison, Brian H.; Brandt, Craig C.; Guss, Adam M.; ...

2015-05-14

Modern biotechnology has the potential to substantially advance the feasibility, structure, and efficiency of future biofuel supply chains. Advances might be direct or indirect. A direct advance would be improving the efficiency of biochemical conversion processes and feedstock production. Direct advances in processing may involve developing improved enzymes and bacteria to convert lignocellulosic feedstocks to ethanol. Progress in feedstock production could include enhancing crop yields via genetic modification or the selection of specific natural variants and breeds. Other direct results of biotechnology might increase the production of fungible biofuels and bioproducts, which would impact the supply chain. Indirect advances mightmore » include modifications to dedicated bioenergy crops that enable them to grow on marginal lands rather than land needed for food production. This study assesses the feasibility and advantages of near-future (10-year) biotechnological developments for a US biomass-based supply chain for bioenergy production. We assume a simplified supply chain of feedstock, logistics and land use, conversion, and products and utilization. The primary focus is how likely developments in feedstock production and conversion technologies will impact bioenergy and biofuels in the USA; a secondary focus is other innovative uses of biotechnologies in the energy arenas. The assessment addresses near-term biofuels based on starch, sugar, and cellulosic feedstocks and considers some longer-term options, such as oil-crop and algal technologies.« less

Protein comparability assessments and potential applicability of high throughput biophysical methods and data visualization tools to compare physical stability profiles

PubMed Central

Alsenaidy, Mohammad A.; Jain, Nishant K.; Kim, Jae H.; Middaugh, C. Russell; Volkin, David B.

2014-01-01

In this review, some of the challenges and opportunities encountered during protein comparability assessments are summarized with an emphasis on developing new analytical approaches to better monitor higher-order protein structures. Several case studies are presented using high throughput biophysical methods to collect protein physical stability data as function of temperature, agitation, ionic strength and/or solution pH. These large data sets were then used to construct empirical phase diagrams (EPDs), radar charts, and comparative signature diagrams (CSDs) for data visualization and structural comparisons between the different proteins. Protein samples with different sizes, post-translational modifications, and inherent stability are presented: acidic fibroblast growth factor (FGF-1) mutants, different glycoforms of an IgG1 mAb prepared by deglycosylation, as well as comparisons of different formulations of an IgG1 mAb and granulocyte colony stimulating factor (GCSF). Using this approach, differences in structural integrity and conformational stability profiles were detected under stress conditions that could not be resolved by using the same techniques under ambient conditions (i.e., no stress). Thus, an evaluation of conformational stability differences may serve as an effective surrogate to monitor differences in higher-order structure between protein samples. These case studies are discussed in the context of potential utility in protein comparability studies. PMID:24659968

Spatially Informed Plant PRA Models for Security Assessment

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

Wheeler, Timothy A.; Thomas, Willard; Thornsbury, Eric

2006-07-01

Traditional risk models can be adapted to evaluate plant response for situations where plant systems and structures are intentionally damaged, such as from sabotage or terrorism. This paper describes a process by which traditional risk models can be spatially informed to analyze the effects of compound and widespread harsh environments through the use of 'damage footprints'. A 'damage footprint' is a spatial map of regions of the plant (zones) where equipment could be physically destroyed or disabled as a direct consequence of an intentional act. The use of 'damage footprints' requires that the basic events from the traditional probabilistic riskmore » assessment (PRA) be spatially transformed so that the failure of individual components can be linked to the destruction of or damage to specific spatial zones within the plant. Given the nature of intentional acts, extensive modifications must be made to the risk models to account for the special nature of the 'initiating events' associated with deliberate adversary actions. Intentional acts might produce harsh environments that in turn could subject components and structures to one or more insults, such as structural, fire, flood, and/or vibration and shock damage. Furthermore, the potential for widespread damage from some of these insults requires an approach that addresses the impacts of these potentially severe insults even when they occur in locations distant from the actual physical location of a component or structure modeled in the traditional PRA. (authors)« less

Protein comparability assessments and potential applicability of high throughput biophysical methods and data visualization tools to compare physical stability profiles.

PubMed

Alsenaidy, Mohammad A; Jain, Nishant K; Kim, Jae H; Middaugh, C Russell; Volkin, David B

2014-01-01

In this review, some of the challenges and opportunities encountered during protein comparability assessments are summarized with an emphasis on developing new analytical approaches to better monitor higher-order protein structures. Several case studies are presented using high throughput biophysical methods to collect protein physical stability data as function of temperature, agitation, ionic strength and/or solution pH. These large data sets were then used to construct empirical phase diagrams (EPDs), radar charts, and comparative signature diagrams (CSDs) for data visualization and structural comparisons between the different proteins. Protein samples with different sizes, post-translational modifications, and inherent stability are presented: acidic fibroblast growth factor (FGF-1) mutants, different glycoforms of an IgG1 mAb prepared by deglycosylation, as well as comparisons of different formulations of an IgG1 mAb and granulocyte colony stimulating factor (GCSF). Using this approach, differences in structural integrity and conformational stability profiles were detected under stress conditions that could not be resolved by using the same techniques under ambient conditions (i.e., no stress). Thus, an evaluation of conformational stability differences may serve as an effective surrogate to monitor differences in higher-order structure between protein samples. These case studies are discussed in the context of potential utility in protein comparability studies.

[A Methodological Quality Assessment of South Korean Nursing Research using Structural Equation Modeling in South Korea].

PubMed

Kim, Jung-Hee; Shin, Sujin; Park, Jin-Hwa

2015-04-01

The purpose of this study was to evaluate the methodological quality of nursing studies using structural equation modeling in Korea. Databases of KISS, DBPIA, and National Assembly Library up to March 2014 were searched using the MeSH terms 'nursing', 'structure', 'model'. A total of 152 studies were screened. After removal of duplicates and non-relevant titles, 61 papers were read in full. Of the sixty-one articles retrieved, 14 studies were published between 1992 and 2000, 27, between 2001 and 2010, and 20, between 2011 and March 2014. The methodological quality of the review examined varied considerably. The findings of this study suggest that more rigorous research is necessary to address theoretical identification, two indicator rule, distribution of sample, treatment of missing values, mediator effect, discriminant validity, convergent validity, post hoc model modification, equivalent models issues, and alternative models issues should be undergone. Further research with robust consistent methodological study designs from model identification to model respecification is needed to improve the validity of the research.

The Exotic Legume Tree Species Acacia holosericea Alters Microbial Soil Functionalities and the Structure of the Arbuscular Mycorrhizal Community▿

PubMed Central

Remigi, P.; Faye, A.; Kane, A.; Deruaz, M.; Thioulouse, J.; Cissoko, M.; Prin, Y.; Galiana, A.; Dreyfus, B.; Duponnois, R.

2008-01-01

The response of microbial functional diversity as well as its resistance to stress or disturbances caused by the introduction of an exotic tree species, Acacia holosericea, ectomycorrhized or not with Pisolithus albus, was examined. The results show that this ectomycorrhizal fungus promotes drastically the growth of this fast-growing tree species in field conditions after 7 years of plantation. Compared to the crop soil surrounding the A. holosericea plantation, this exotic tree species, associated or not with the ectomycorrhizal symbiont, induced strong modifications in soil microbial functionalities (assessed by measuring the patterns of in situ catabolic potential of microbial communities) and reduced soil resistance in response to increasing stress or disturbance (salinity, temperature, and freeze-thaw and wet-dry cycles). In addition, A. holosericea strongly modified the structure of arbuscular mycorrhizal fungus communities. These results show clearly that exotic plants may be responsible for important changes in soil microbiota affecting the structure and functions of microbial communities. PMID:18203858

Chronic exposure to glufosinate-ammonium induces spatial memory impairments, hippocampal MRI modifications and glutamine synthetase activation in mice.

PubMed

Calas, André-Guilhem; Richard, Olivier; Même, Sandra; Beloeil, Jean-Claude; Doan, Bich-Thuy; Gefflaut, Thierry; Même, William; Crusio, Wim E; Pichon, Jacques; Montécot, Céline

2008-07-01

Glufosinate-ammonium (GLA), the active compound of a worldwide-used herbicide, acts by inhibiting the plant glutamine synthetase (GS) leading to a lethal accumulation of ammonia. GS plays a pivotal role in the mammalian brain where it allows neurotransmitter glutamate recycling within astroglia. Clinical studies report that an acute GLA ingestion induces convulsions and memory impairment in humans. Toxicological studies performed at doses used for herbicidal activity showed that GLA is probably harmless at short or medium range periods. However, effects of low doses of GLA on chronically exposed subjects are not known. In our study, C57BL/6J mice were treated during 10 weeks three times a week with 2.5, 5 and 10mg/kg of GLA. Effects of this chronic treatment were assessed at behavioral, structural and metabolic levels by using tests of spatial memory, locomotor activity and anxiety, hippocampal magnetic resonance imaging (MRI) texture analysis, and hippocampal GS activity assay, respectively. Chronic GLA treatments have effects neither on anxiety nor on locomotor activity of mice but at 5 and 10mg/kg induce (1) mild memory impairments, (2) a modification of hippocampal texture and (3) a significant increase in hippocampal GS activity. It is suggested that these modifications may be causally linked one to another. Since glutamate is the main neurotransmitter in hippocampus where it plays a crucial role in spatial memory, hippocampal MRI texture and spatial memory alterations might be the consequences of hippocampal glutamate homeostasis modification revealed by increased GS activity in hippocampus. The present study provides the first data that show cerebral alterations after chronic exposure to GLA.

Lorentz invariance with an invariant energy scale.

PubMed

Magueijo, João; Smolin, Lee

2002-05-13

We propose a modification of special relativity in which a physical energy, which may be the Planck energy, joins the speed of light as an invariant, in spite of a complete relativity of inertial frames and agreement with Einstein's theory at low energies. This is accomplished by a nonlinear modification of the action of the Lorentz group on momentum space, generated by adding a dilatation to each boost in such a way that the Planck energy remains invariant. The associated algebra has unmodified structure constants. We also discuss the resulting modifications of field theory and suggest a modification of the equivalence principle which determines how the new theory is embedded in general relativity.

Recent advances in the chemical modification of unsaturated polymers

NASA Technical Reports Server (NTRS)

Schulz, D. N.; Turner, S. R.; Golub, M. A.

1982-01-01

The present discussion has the objective to update the most comprehensive reviews on the considered subject and to fill in the gaps of less complete, but more modern treatments. Only simple chemical functionalization or structural modification of unsaturated polymers are covered, and the literature of diene polymer modification since 1974 is emphasized. Attention is given to hydrogenation, halogenation and hydrohalogenation, cyclization, cis-trans isomerization, epoxidation, ene and other cycloaddition reactions, sulfonation, carboxylation, phosphonylation, sulfenyl chloride addition, carbene addition, metalation, and silylation. It is pointed out that modern synthetic reagents and catalysts have been advantageously employed to improve process and/or product quality. Synthetic techniques have been refined to allow the selective modification of specific polymer microstructures or blocks.

Plasma assisted surface coating/modification processes - An emerging technology

NASA Technical Reports Server (NTRS)

Spalvins, T.

1987-01-01

A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation. These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

Plasma assisted surface coating/modification processes: An emerging technology

NASA Technical Reports Server (NTRS)

Spalvins, T.

1986-01-01

A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation). These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

Consume, Modify, Share (CMS): The Interplay between Individual Decisions and Structural Network Properties in the Diffusion of Information

PubMed Central

Koren, Hila; Kaminer, Ido

2016-01-01

Widely used information diffusion models such as Independent Cascade Model, Susceptible Infected Recovered (SIR) and others fail to acknowledge that information is constantly subject to modification. Some aspects of information diffusion are best explained by network structural characteristics while in some cases strong influence comes from individual decisions. We introduce reinvention, the ability to modify information, as an individual level decision that affects the diffusion process as a whole. Based on a combination of constructs from the Diffusion of Innovations and the Critical Mass Theories, the present study advances the CMS (consume, modify, share) model which accounts for the interplay between network structure and human behavior and interactions. The model's building blocks include processes leading up to and following the formation of a critical mass of information adopters and disseminators. We examine the formation of an inflection point, information reach, sustainability of the diffusion process and collective value creation. The CMS model is tested on two directed networks and one undirected network, assuming weak or strong ties and applying constant and relative modification schemes. While all three networks are designed for disseminating new knowledge they differ in structural properties. Our findings suggest that modification enhances the diffusion of information in networks that support undirected connections and carries the biggest effect when information is shared via weak ties. Rogers' diffusion model and traditional information contagion models are fine tuned. Our results show that modifications not only contribute to a sustainable diffusion process, but also aid information in reaching remote areas of the network. The results point to the importance of cultivating weak ties, allowing reciprocal interaction among nodes and supporting the modification of information in promoting diffusion processes. These results have theoretical and practical implications for designing networks aimed at accelerating the creation and diffusion of information. PMID:27798636

Consume, Modify, Share (CMS): The Interplay between Individual Decisions and Structural Network Properties in the Diffusion of Information.

PubMed

Koren, Hila; Kaminer, Ido; Raban, Daphne Ruth

2016-01-01

Widely used information diffusion models such as Independent Cascade Model, Susceptible Infected Recovered (SIR) and others fail to acknowledge that information is constantly subject to modification. Some aspects of information diffusion are best explained by network structural characteristics while in some cases strong influence comes from individual decisions. We introduce reinvention, the ability to modify information, as an individual level decision that affects the diffusion process as a whole. Based on a combination of constructs from the Diffusion of Innovations and the Critical Mass Theories, the present study advances the CMS (consume, modify, share) model which accounts for the interplay between network structure and human behavior and interactions. The model's building blocks include processes leading up to and following the formation of a critical mass of information adopters and disseminators. We examine the formation of an inflection point, information reach, sustainability of the diffusion process and collective value creation. The CMS model is tested on two directed networks and one undirected network, assuming weak or strong ties and applying constant and relative modification schemes. While all three networks are designed for disseminating new knowledge they differ in structural properties. Our findings suggest that modification enhances the diffusion of information in networks that support undirected connections and carries the biggest effect when information is shared via weak ties. Rogers' diffusion model and traditional information contagion models are fine tuned. Our results show that modifications not only contribute to a sustainable diffusion process, but also aid information in reaching remote areas of the network. The results point to the importance of cultivating weak ties, allowing reciprocal interaction among nodes and supporting the modification of information in promoting diffusion processes. These results have theoretical and practical implications for designing networks aimed at accelerating the creation and diffusion of information.

Behavior modification therapy in hyperactive children. Research and clinical implications.

PubMed

Wolraich, M L

1979-09-01

One hundred fifty-seven studies employing behavior modification in the management of hyperactive and disruptive children were reviewed. The studies were analyzed against standards of scientific validity. The review found: (1) behavior modification was effective in alleviating problem behaviors; (2) token programs were the most commonly used; (3) both positive reinforcement and punishment were effective; positive reinforcement, however, had the advantage of improving self-esteem; (4) behavioral problems occurring in the home most likely require a home-based program; (5) behavior modification and stimulant medication can be used simultaneously, often with additive effects; and (6) long-term benefits beyond one year have not been assessed.

Tribute to the contribution of Gerard Lallenment to structural dynamics

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

Los Alamos National Laboratory

The Society for Experimental Mechanics and the International Modal Analysis Conference recognize the remarkable contribution to experimental mechanics, mechanical engineering and structural dynamics of Professor Gerard Lallement, from the University of Franche-Comte, France. A special session is organized during the IMAC-XX to outline the many achievements of Gerard Lallement in the fields of modal analysis, structural system identification, the theory and practice of structural modification, component mode synthesis and finite element model updating. The purpose of this publication is not to provide an exhaustive account of Gerard Lallement's contribution to structural dynamics. Numerous references are provided that should help themore » interested reader learn more about the many aspects of his work. Instead, the significance of this work is illustrated by discussing the role of structural dynamics in industrial applications and its future challenges. The technical aspects of Gerard Lallement's work are illustrated with a discussion of structural modification, modeling error localization and model updating.« less

The Androgen Receptor and Its Use in Biological Assays: Looking Toward Effect-Based Testing and Its Applications

PubMed Central

Cadwallader, Amy B.; Lim, Carol S.; Rollins, Douglas E.; Botrè, Francesco

2015-01-01

Steroid abuse is a growing problem among amateur and professional athletes. Because of an inundation of newly and illegally synthesized steroids with minor structural modifications and other designer steroid receptor modulators, there is a need to develop new methods of detection which do not require prior knowledge of the abused steroid structure. The number of designer steroids currently being abused is unknown because detection methods in general are only identifying substances with a known structure. The detection of doping is moving away from merely checking for exposure to prohibited substance toward detecting an effect of prohibited substances, as biological assays can do. Cell-based biological assays are the next generation of assays which should be utilized by antidoping laboratories; they can detect androgenic anabolic steroid and other human androgen receptor (hAR) ligand presence without knowledge of their structure and assess the relative biological activity of these compounds. This review summarizes the hAR and its action and discusses its relevance to sports doping and its use in biological assays. PMID:22080898

Micro- and nanoscale devices for the investigation of epigenetics and chromatin dynamics

NASA Astrophysics Data System (ADS)

Aguilar, Carlos A.; Craighead, Harold G.

2013-10-01

Deoxyribonucleic acid (DNA) is the blueprint on which life is based and transmitted, but the way in which chromatin -- a dynamic complex of nucleic acids and proteins -- is packaged and behaves in the cellular nucleus has only begun to be investigated. Epigenetic modifications sit 'on top of' the genome and affect how DNA is compacted into chromatin and transcribed into ribonucleic acid (RNA). The packaging and modifications around the genome have been shown to exert significant influence on cellular behaviour and, in turn, human development and disease. However, conventional techniques for studying epigenetic or conformational modifications of chromosomes have inherent limitations and, therefore, new methods based on micro- and nanoscale devices have been sought. Here, we review the development of these devices and explore their use in the study of DNA modifications, chromatin modifications and higher-order chromatin structures.

A miniaturized technique for assessing protein thermodynamics and function using fast determination of quantitative cysteine reactivity.

PubMed

Isom, Daniel G; Marguet, Philippe R; Oas, Terrence G; Hellinga, Homme W

2011-04-01

Protein thermodynamic stability is a fundamental physical characteristic that determines biological function. Furthermore, alteration of thermodynamic stability by macromolecular interactions or biochemical modifications is a powerful tool for assessing the relationship between protein structure, stability, and biological function. High-throughput approaches for quantifying protein stability are beginning to emerge that enable thermodynamic measurements on small amounts of material, in short periods of time, and using readily accessible instrumentation. Here we present such a method, fast quantitative cysteine reactivity, which exploits the linkage between protein stability, sidechain protection by protein structure, and structural dynamics to characterize the thermodynamic and kinetic properties of proteins. In this approach, the reaction of a protected cysteine and thiol-reactive fluorogenic indicator is monitored over a gradient of temperatures after a short incubation time. These labeling data can be used to determine the midpoint of thermal unfolding, measure the temperature dependence of protein stability, quantify ligand-binding affinity, and, under certain conditions, estimate folding rate constants. Here, we demonstrate the fQCR method by characterizing these thermodynamic and kinetic properties for variants of Staphylococcal nuclease and E. coli ribose-binding protein engineered to contain single, protected cysteines. These straightforward, information-rich experiments are likely to find applications in protein engineering and functional genomics. Copyright © 2010 Wiley-Liss, Inc.

Profiling of integral membrane proteins and their post translational modifications using high-resolution mass spectrometry

PubMed Central

Souda, Puneet; Ryan, Christopher M.; Cramer, William A.; Whitelegge, Julian

2011-01-01

Integral membrane proteins pose challenges to traditional proteomics approaches due to unique physicochemical properties including hydrophobic transmembrane domains that limit solubility in aqueous solvents. A well resolved intact protein molecular mass profile defines a protein’s native covalent state including post-translational modifications, and is thus a vital measurement toward full structure determination. Both soluble loop regions and transmembrane regions potentially contain post-translational modifications that must be characterized if the covalent primary structure of a membrane protein is to be defined. This goal has been achieved using electrospray-ionization mass spectrometry (ESI-MS) with low-resolution mass analyzers for intact protein profiling, and high-resolution instruments for top-down experiments, toward complete covalent primary structure information. In top-down, the intact protein profile is supplemented by gas-phase fragmentation of the intact protein, including its transmembrane regions, using collisionally activated and/or electroncapture dissociation (CAD/ECD) to yield sequence-dependent high-resolution MS information. Dedicated liquid chromatography systems with aqueous/organic solvent mixtures were developed allowing us to demonstrate that polytopic integral membrane proteins are amenable to ESI-MS analysis, including top-down measurements. Covalent post-translational modifications are localized regardless of their position in transmembrane domains. Top-down measurements provide a more detail oriented high-resolution description of post-transcriptional and post-translational diversity for enhanced understanding beyond genomic translation. PMID:21982782

Profiling of integral membrane proteins and their post translational modifications using high-resolution mass spectrometry.

PubMed

Souda, Puneet; Ryan, Christopher M; Cramer, William A; Whitelegge, Julian

2011-12-01

Integral membrane proteins pose challenges to traditional proteomics approaches due to unique physicochemical properties including hydrophobic transmembrane domains that limit solubility in aqueous solvents. A well resolved intact protein molecular mass profile defines a protein's native covalent state including post-translational modifications, and is thus a vital measurement toward full structure determination. Both soluble loop regions and transmembrane regions potentially contain post-translational modifications that must be characterized if the covalent primary structure of a membrane protein is to be defined. This goal has been achieved using electrospray-ionization mass spectrometry (ESI-MS) with low-resolution mass analyzers for intact protein profiling, and high-resolution instruments for top-down experiments, toward complete covalent primary structure information. In top-down, the intact protein profile is supplemented by gas-phase fragmentation of the intact protein, including its transmembrane regions, using collisionally activated and/or electron-capture dissociation (CAD/ECD) to yield sequence-dependent high-resolution MS information. Dedicated liquid chromatography systems with aqueous/organic solvent mixtures were developed allowing us to demonstrate that polytopic integral membrane proteins are amenable to ESI-MS analysis, including top-down measurements. Covalent post-translational modifications are localized regardless of their position in transmembrane domains. Top-down measurements provide a more detail oriented high-resolution description of post-transcriptional and post-translational diversity for enhanced understanding beyond genomic translation. Copyright © 2011 Elsevier Inc. All rights reserved.

Synthesis of Nanoscale TiO2 and Study of the Effect of Their Crystal Structure on Single Cell Response

PubMed Central

Ismagilov, Z. R.; Shikina, N. V.; Mazurkova, N. A.; Tsikoza, L. T.; Tuzikov, F. V.; Ushakov, V. A.; Ishchenko, A. V.; Rudina, N. A.; Korneev, D. V.; Ryabchikova, E. I.

2012-01-01

To study the effect of nanoscale titanium dioxide (TiO2) on cell responses, we synthesized four modifications of the TiO2 (amorphous, anatase, brookite, and rutile) capable of keeping their physicochemical characteristics in a cell culture medium. The modifications of nanoscale TiO2 were obtained by hydrolysis of TiCl4 and Ti(i-OC3H7)4 (TIP) upon variation of the synthesis conditions; their textural, morphological, structural, and dispersion characteristics were examined by a set of physicochemical methods: XRD, BET, SAXS, DLS, AFM, SEM, and HR-TEM. The effect of synthesis conditions (nature of precursor, pH, temperature, and addition of a complexing agent) on the structural-dispersion properties of TiO2 nanoparticles was studied. The hydrolysis methods providing the preparation of amorphous, anatase, brookite, and rutile modifications of TiO2 nanoparticles 3–5 nm in size were selected. Examination of different forms of TiO2 nanoparticles interaction with MDCK cells by transmission electron microscopy of ultrathin sections revealed different cell responses after treatment with different crystalline modifications and amorphous form of TiO2. The obtained results allowed us to conclude that direct contact of the nanoparticles with cell plasma membrane is the primary and critical step of their interaction and defines a subsequent response of the cell. PMID:22623903

78 FR 18331 - East Tennessee Natural Gas, LLC; Notice of Intent To Prepare an Environmental Assessment for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-26

... Glade Spring Compressor Station and Fordtown Compressor Station. The Kingsport Expansion Project would...; and modifications at the Fordtown Compressor Station. Washington County, Virginia construction of... increase capacity. modifications at the Glade Spring Compressor Station. Washington and Smyth Counties...

78 FR 42062 - Columbia Gas Transmission, LLC; Notice of Intent to Prepare an Environmental Assessment and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-15

... facilities: New compressor station (Redd Farm Compressor Station) on Columbia's existing Line 1570 in... setting; Modifications to the Smithfield Compressor Station consisting of upgrades to the existing... coolers; Modifications to the Glenville Compressor Station by installing two gas-fired turbines, each...

40 CFR 58.14 - System modification.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.14 System modification. (a) The State, or where... monitoring network that complies with the findings of the network assessments required every 5 years by § 58... schedule with respect to the SLAMS network are subject to the approval of the EPA Regional Administrator...

40 CFR 58.14 - System modification.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.14 System modification. (a) The State, or where... monitoring network that complies with the findings of the network assessments required every 5 years by § 58... schedule with respect to the SLAMS network are subject to the approval of the EPA Regional Administrator...

Promoting Student Learning in a Large General Chemistry Course

ERIC Educational Resources Information Center

Buchanan, Stacey A.; Reynolds, Melissa M.; Duersch, Brett S.; Lohr, Lawrence L.; Coppola, Brian P.; Zusho, Akane; Pintrich, Paul R.

2004-01-01

Based on recent reports in the science education literature, curricular modifications were made to one section of a freshman-level general chemistry course. Assessment results indicate that these modifications resulted in a more student-centered learning environment and increased student learning and satisfaction as compared to results from…

24 CFR 901.110 - PHA request for exclusion or modification of an indicator or component.

Code of Federal Regulations, 2010 CFR

2010-04-01

... HOUSING, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT PUBLIC HOUSING MANAGEMENT ASSESSMENT PROGRAM § 901... right to request the exclusion or modification of any indicator or component in its management... its PHMAP certification submission to the State/Area Office along with supporting documentary...

Modification of Children's Racial Attitudes. Final Progress Report.

ERIC Educational Resources Information Center

Katz, Phyllis

This study investigated some of the attitudinal and behavioral components of racial prejudice in elementary school children. It also assessed the effectiveness of various modification procedures upon children's racial attitudes and inter-group behavior at different age levels. A four-stage research design was used. The pre-test stage involved…

Operant conditioning-based behavior modification: one approach to treating somatic disorders.

PubMed

LeBow, M D

1975-01-01

The applicability of behavior modification as a process for treating somatic difficulties is examined within the framework of measurement, modification, and evaluation. Illustrations of this process are presented throughout. In particular, the last section of the paper gives an example of a currently operative and multifaceted approach to the problem of obesity. Among the topics considered herein are the use of behavioral contracts that specify ameliorative weight reduction practices and the assessment as well as manipulation of eating speed.

The concomitant effects of phrase length and informational content in sentence comprehension.

PubMed

Thornton, R; MacDonald, M C; Arnold, J E

2000-03-01

Recent evidence suggests that phrase length plays a crucial role in modification ambiguities. Using a self-paced reading task, we extended these results by examining the additional pragmatic effects that length manipulations may exert. The results demonstrate that length not only modulates modification preferences directly, but that it also necessarily changes the informational content of a sentence, which itself affects modification preferences. Our findings suggest that the same length manipulation affects multiple sources of constraints, both structural and pragmatic, which can each exert differing effects on processing.

FIBER OPTICS: Role of point defects in the photosensitivity of hydrogen-loaded phosphosilicate glass

NASA Astrophysics Data System (ADS)

Larionov, Yu V.

2010-08-01

It is shown that point defect modifications in hydrogen-loaded phosphosilicate glass (PSG) do not play a central role in determining its photosensitivity. Photochemical reactions that involve a two-step point defect modification and pre-exposure effect are incapable of accounting for photoinduced refractive index changes. It seems likely that a key role in UV-induced refractive index modifications is played by structural changes in the PSG network. Experimental data are presented that demonstrate intricate network rearrangement dynamics during UV exposure of PSG.

Detection of histone modifications in plant leaves.

PubMed

Jaskiewicz, Michal; Peterhansel, Christoph; Conrath, Uwe

2011-09-23

Chromatin structure is important for the regulation of gene expression in eukaryotes. In this process, chromatin remodeling, DNA methylation, and covalent modifications on the amino-terminal tails of histones H3 and H4 play essential roles(1-2). H3 and H4 histone modifications include methylation of lysine and arginine, acetylation of lysine, and phosphorylation of serine residues(1-2). These modifications are associated either with gene activation, repression, or a primed state of gene that supports more rapid and robust activation of expression after perception of appropriate signals (microbe-associated molecular patterns, light, hormones, etc.)(3-7). Here, we present a method for the reliable and sensitive detection of specific chromatin modifications on selected plant genes. The technique is based on the crosslinking of (modified) histones and DNA with formaldehyde(8,9), extraction and sonication of chromatin, chromatin immunoprecipitation (ChIP) with modification-specific antibodies(9,10), de-crosslinking of histone-DNA complexes, and gene-specific real-time quantitative PCR. The approach has proven useful for detecting specific histone modifications associated with C(4;) photosynthesis in maize(5,11) and systemic immunity in Arabidopsis(3).

Managing medical technology: lessons for the United States from Quebec and France.

PubMed

Rosenau, P V

2000-01-01

Important modifications to technology assessment, diffusion, adoption, and utilization must take place if the United States is to better employ medical technology and save resources so as to assure access for the uninsured and underinsured. The United States can learn from other health systems that are more successful in achieving these goals. The author selects for comparison the health systems of France and Quebec. The discussion focuses on the differences between the three systems in the management of medical technology on a range of policy-relevant dimensions, including health system structure, attitudes about planning versus market competition, government regulation, the balance between decentralization and centralization, the needs of the individual and those of the society, linkages between technology assessment and policy-making, and the importance of medical technology assessment for medical practice. Seven specific recommendations are made for better managing medical technology in the United States, drawing on what can be observed from the experiences of Quebec and France.

Experimental assessment of thermal effects of high power density light stimulation for optogenetics control of deep brain structures (Conference Presentation)

NASA Astrophysics Data System (ADS)

Senova, Suhan; Scisniak, Ilona; Chiang, Chih Chieh; Doignon, Isabelle; Martin, Claire; Palfi, Stephane; Chaillet, Antoine; Pain, Frederic

2016-03-01

2D surface maps of light distribution and temperature increase were recorded in wild type anesthetized rats brains during 90s light stimulation at 478nm (blue) and 638nm (red) with continuous or pulsed optical stimulations with corresponding power ranging from 100 up to 1200 mW/mm² at the output of an optical fiber. Post mortem maps were recorded in the same animals to assess the cooling effect of blood flow. Post mortem histological analysis were carried out to assess whether high power light stimulations had phototoxic effects or could trigger non physiological functional activation. Temperature increase remains below physiological changes (0,5 -1°) for stimulations up to 400mW/mm² at 40Hz. . Histology did not show significant irreversible modifications or damage to the tissues. The spatial profile of light distribution and heat were correlated and demonstrate as expected a rapid attenuation with diatnce to the fiber.

Nano-modification to improve the ductility of cementitious composites

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

Yeşilmen, Seda; Al-Najjar, Yazin; Balav, Mohammad Hatam

2015-10-15

Effect of nano-sized mineral additions on ductility of engineered cementitious composites (ECC) containing high volumes of fly ash was investigated at different hydration degrees. Various properties of ECC mixtures with different mineral additions were compared in terms of microstructural properties of matrix, fiber-matrix interface, and fiber surface to assess improvements in ductility. Microstructural characterization was made by measuring pore size distributions through mercury intrusion porosimetry (MIP). Hydration characteristics were assessed using thermogravimetric analysis/differential thermal analysis (TGA/DTA), and fiber-matrix interface and fiber surface characteristics were assessed using scanning electron microscopy (SEM) through a period of 90 days. Moreover, compressive and flexuralmore » strength developments were monitored for the same period. Test results confirmed that mineral additions could significantly improve both flexural strength and ductility of ECC, especially at early ages. Cheaper Nano-CaCO{sub 3} was more effective compared to nano-silica. However, the crystal structure of CaCO{sub 3} played a very important role in the range of expected improvements.« less

Quantitative risk assessment system (QRAS)

NASA Technical Reports Server (NTRS)

Tan, Zhibin (Inventor); Mosleh, Ali (Inventor); Weinstock, Robert M (Inventor); Smidts, Carol S (Inventor); Chang, Yung-Hsien (Inventor); Groen, Francisco J (Inventor); Swaminathan, Sankaran (Inventor)

2001-01-01

A quantitative risk assessment system (QRAS) builds a risk model of a system for which risk of failure is being assessed, then analyzes the risk of the system corresponding to the risk model. The QRAS performs sensitivity analysis of the risk model by altering fundamental components and quantifications built into the risk model, then re-analyzes the risk of the system using the modifications. More particularly, the risk model is built by building a hierarchy, creating a mission timeline, quantifying failure modes, and building/editing event sequence diagrams. Multiplicities, dependencies, and redundancies of the system are included in the risk model. For analysis runs, a fixed baseline is first constructed and stored. This baseline contains the lowest level scenarios, preserved in event tree structure. The analysis runs, at any level of the hierarchy and below, access this baseline for risk quantitative computation as well as ranking of particular risks. A standalone Tool Box capability exists, allowing the user to store application programs within QRAS.

Improving the Welfare of a Zoo-Housed Male Drill (Mandrillus leucophaeus poensis) Aggressive Toward Visitors.

PubMed

Martín, Olga; Vinyoles, Dolors; García-Galea, Eduardo; Maté, Carmen

2016-01-01

Improving the welfare of nonhuman animals in captivity and maintaining behavioral competence for future conservation purposes is of the highest priority for zoos. The behavior of an aggressive male drill (Mandrillus leucophaeus poensis) was assessed in Barcelona Zoo. The 2-year study presented in this article examined the effects of introducing changes in the exhibit of the drill to improve his welfare by analyzing scan behaviors. First, a partial visual barrier was applied and proved to be insufficient to decrease the long-term stress indicators assessed. Next, a feeding enrichment program was implemented. The results supported the hypothesis that feeding and explorative activities would increase, whereas apathetic and stereotypic behaviors would decrease. However, visitor-directed aggression did not vary, indicating that more profound structural modifications were needed to reduce the negative impact of the agonistic interactions between the drill and the public. The study emphasized the usefulness of environmental enrichment evaluations in assessing captive animal welfare.

Low damage electrical modification of 4H-SiC via ultrafast laser irradiation

NASA Astrophysics Data System (ADS)

Ahn, Minhyung; Cahyadi, Rico; Wendorf, Joseph; Bowen, Willie; Torralva, Ben; Yalisove, Steven; Phillips, Jamie

2018-04-01

The electrical properties of 4H-SiC under ultrafast laser irradiation in the low fluence regime (<0.50 J/cm2) are presented. The appearance of high spatial frequency laser induced periodic surface structures is observed at a fluence near 0.25 J/cm2 and above, with variability in environments like in air, nitrogen, and a vacuum. In addition to the formation of periodic surface structures, ultrafast laser irradiation results in possible surface oxidation and amorphization of the material. Lateral conductance exhibits orders of magnitude increase, which is attributed to either surface conduction or modification of electrical contact properties, depending on the initial material conductivity. Schottky barrier formation on ultrafast laser irradiated 4H-SiC shows an increase in the barrier height, an increase in the ideality factor, and sub-bandgap photovoltaic responses, suggesting the formation of photo-active point defects. The results suggest that the ultrafast laser irradiation technique provides a means of engineering spatially localized structural and electronic modification of wide bandgap materials such as 4H-SiC with relatively low surface damage via low temperature processing.

A new method of passive modifications for partial frequency assignment of general structures

NASA Astrophysics Data System (ADS)

Belotti, Roberto; Ouyang, Huajiang; Richiedei, Dario

2018-01-01

The assignment of a subset of natural frequencies to vibrating systems can be conveniently achieved by means of suitable structural modifications. It has been observed that such an approach usually leads to the undesired change of the unassigned natural frequencies, which is a phenomenon known as frequency spill-over. Such an issue has been dealt with in the literature only in simple specific cases. In this paper, a new and general method is proposed that aims to assign a subset of natural frequencies with low spill-over. The optimal structural modifications are determined through a three-step procedure that considers both the prescribed eigenvalues and the feasibility constraints, assuring that the obtained solution is physically realizable. The proposed method is therefore applicable to very general vibrating systems, such as those obtained through the finite element method. The numerical difficulties that may occur as a result of employing the method are also carefully addressed. Finally, the capabilities of the method are validated in three test-cases in which both lumped and distributed parameters are modified to obtain the desired eigenvalues.

Enzymatic modification of phospholipids for functional applications and human nutrition.

PubMed

Guo, Zheng; Vikbjerg, Anders F; Xu, Xuebing

2005-05-01

Rapid progress in biochemistry of phospholipids and evolution of modern bioengineering has brought forth a number of novel concepts and technical advancements in the modification of phospholipids for industrial applications and human nutrition. Highlights cover preparation of novel phospholipid analogs based on the latest understanding of pivotal role of phospholipids in manifold biological processes, exploration of remarkable application potentials of phospholipids in meliorating human health, as well as development of new chemical and biotechnological approaches applied to the modification of phospholipids. This work reviews the natural occurrence and structural characteristics of phospholipids, their updated knowledge on manifold biological and nutritional functions, traditional and novel physical and chemical approaches to modify phospholipids as well as their applications to obtain novel phospholipids, and brief introduction of the efforts focusing on de novo syntheses of phospholipids. Special attention is given to the summary of molecular structural characteristics and catalytic properties of multiple phospholipases, which helps to interpret experimental phenomena and to improve reaction design. This will of course provide fundamental bases also for the development of enzymatic technology to produce structured or modified phospholipids.

Basic evaluation of typical nanoporous silica nanoparticles in being drug carrier: Structure, wettability and hemolysis.

PubMed

Li, Jing; Guo, Yingyu

2017-04-01

Herein, the present work devoted to study the basic capacity of nanoporous silica nanoparticles in being drug carrier that covered structure, wettability and hemolysis so as to provide crucial evaluation. Typical nanoporous silica nanoparticles that consist of nanoporous silica nanoparticles (NSN), amino modified nanoporous silica nanoparticles (amino-NSN), carboxyl modified nanoporous silica nanoparticles (carboxyl-NSN) and hierachical nanoporous silica nanoparticles (hierachical-NSN) were studied. The results showed that their wettability and hemolysis were closely related to structure and surface modification. Basically, wettability became stronger as the amount of OH on the surface of NSN was higher. Both large nanopores and surface modification can reduce the wettability of NSN. Furthermore, NSN series were safe to be used when they circulated into the blood in low concentration, while if high concentration can not be avoided during administration, high porosity or amino modification of NSN were safer to be considered. It is believed that the basic evaluation of NSN can make contribution in providing scientific instruction for designing drug loaded NSN systems. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of robust hydrogel coatings on polydimethylsiloxane substrates using micropillar anchor structures with chemical surface modification.

PubMed

Zhang, Hongbin; Bian, Chao; Jackson, John K; Khademolhosseini, Farzad; Burt, Helen M; Chiao, Mu

2014-06-25

A durable hydrophilic and protein-resistant surface of polydimethylsiloxane (PDMS) based devices is desirable in many biomedical applications such as implantable and microfluidic devices. This paper describes a stable antifouling hydrogel coating on PDMS surfaces. The coating method combines chemical modification and surface microstructure fabrication of PDMS substrates. Three-(trimethoxysilyl)propyl methacrylates containing C═C groups were used to modify PDMS surfaces with micropillar array structures fabricated by a replica molding method. The micropillar structures increase the surface area of PDMS surfaces, which facilitates secure bonding with a hydrogel coating compared to flat PMDS surfaces. The adhesion properties of the hydrogel coating on PDMS substrates were characterized using bending, stretching and water immersion tests. Long-term hydrophilic stability (maintaining a contact angle of 55° for a month) and a low protein adsorption property (35 ng/cm(2) of adsorbed BSA-FITC) of the hydrogel coated PDMS were demonstrated. This coating method is suitable for PDMS modification with most crosslinkable polymers containing C═C groups, which can be useful for improving the anti-biofouling performance of PDMS-based biomedical microdevices.

Magnetic and topographical modifications of amorphous Co-Fe thin films induced by high energy Ag7+ ion irradiation

NASA Astrophysics Data System (ADS)

Pookat, G.; Hysen, T.; Al-Harthi, S. H.; Al-Omari, I. A.; Lisha, R.; Avasthi, D. K.; Anantharaman, M. R.

2013-09-01

We have investigated the effects of swift heavy ion irradiation on thermally evaporated 44 nm thick, amorphous Co77Fe23 thin films on silicon substrates using 100 MeV Ag7+ ions fluences of 1 × 1011 ions/cm2, 1 × 1012 ions/cm2, 1 × 1013 ions/cm2, and 3 × 1013 ions/cm2. The structural modifications upon swift heavy irradiation were investigated using glancing angle X-ray diffraction. The surface morphological evolution of thin film with irradiation was studied using Atomic Force Microscopy. Power spectral density analysis was used to correlate the roughness variation with structural modifications investigated using X-ray diffraction. Magnetic measurements were carried out using vibrating sample magnetometry and the observed variation in coercivity of the irradiated films is explained on the basis of stress relaxation. Magnetic force microscopy images are subjected to analysis using the scanning probe image processor software. These results are in agreement with the results obtained using vibrating sample magnetometry. The magnetic and structural properties are correlated.

RNA Framework: an all-in-one toolkit for the analysis of RNA structures and post-transcriptional modifications.

PubMed

Incarnato, Danny; Morandi, Edoardo; Simon, Lisa Marie; Oliviero, Salvatore

2018-06-09

RNA is emerging as a key regulator of a plethora of biological processes. While its study has remained elusive for decades, the recent advent of high-throughput sequencing technologies provided the unique opportunity to develop novel techniques for the study of RNA structure and post-transcriptional modifications. Nonetheless, most of the required downstream bioinformatics analyses steps are not easily reproducible, thus making the application of these techniques a prerogative of few laboratories. Here we introduce RNA Framework, an all-in-one toolkit for the analysis of most NGS-based RNA structure probing and post-transcriptional modification mapping experiments. To prove the extreme versatility of RNA Framework, we applied it to both an in-house generated DMS-MaPseq dataset, and to a series of literature available experiments. Notably, when starting from publicly available datasets, our software easily allows replicating authors' findings. Collectively, RNA Framework provides the most complete and versatile toolkit to date for a rapid and streamlined analysis of the RNA epistructurome. RNA Framework is available for download at: http://www.rnaframework.com.

Limited family structure and BRCA gene mutation status in single cases of breast cancer.

PubMed

Weitzel, Jeffrey N; Lagos, Veronica I; Cullinane, Carey A; Gambol, Patricia J; Culver, Julie O; Blazer, Kathleen R; Palomares, Melanie R; Lowstuter, Katrina J; MacDonald, Deborah J

2007-06-20

An autosomal dominant pattern of hereditary breast cancer may be masked by small family size or transmission through males given sex-limited expression. To determine if BRCA gene mutations are more prevalent among single cases of early onset breast cancer in families with limited vs adequate family structure than would be predicted by currently available probability models. A total of 1543 women seen at US high-risk clinics for genetic cancer risk assessment and BRCA gene testing were enrolled in a prospective registry study between April 1997 and February 2007. Three hundred six of these women had breast cancer before age 50 years and no first- or second-degree relatives with breast or ovarian cancers. The main outcome measure was whether family structure, assessed from multigenerational pedigrees, predicts BRCA gene mutation status. Limited family structure was defined as fewer than 2 first- or second-degree female relatives surviving beyond age 45 years in either lineage. Family structure effect and mutation probability by the Couch, Myriad, and BRCAPRO models were assessed with stepwise multiple logistic regression. Model sensitivity and specificity were determined and receiver operating characteristic curves were generated. Family structure was limited in 153 cases (50%). BRCA gene mutations were detected in 13.7% of participants with limited vs 5.2% with adequate family structure. Family structure was a significant predictor of mutation status (odds ratio, 2.8; 95% confidence interval, 1.19-6.73; P = .02). Although none of the models performed well, receiver operating characteristic analysis indicated that modification of BRCAPRO output by a corrective probability index accounting for family structure was the most accurate BRCA gene mutation status predictor (area under the curve, 0.72; 95% confidence interval, 0.63-0.81; P<.001) for single cases of breast cancer. Family structure can affect the accuracy of mutation probability models. Genetic testing guidelines may need to be more inclusive for single cases of breast cancer when the family structure is limited and probability models need to be recreated using limited family history as an actual variable.

Multihospital system management structure to meet the challenges of the 1980s.

PubMed

Lloyd, R W

1985-07-01

An improved operational structure is necessary to deal with today's rapidly changing health care environment. This article explores the alternatives for organizational structure that have been used to date and recommends modifications which will lead to more proactive management.

Mobility power flow analysis of an L-shaped plate structure subjected to distributed loading

NASA Technical Reports Server (NTRS)

Cuschieri, J. M.; Cimmerman, B.

1990-01-01

An analytical investigation based in the Mobility Power Flow (MPF) method is presented for the determination of the vibrational response and power flow for two coupled flat plate structures in an L-shaped configuration, subjected to distributed excitation. The principle of the MPF method consists of dividing the global structure into a series of subsystems coupled together using mobility functions. Each separate subsystem is analyzed independently to determine the structural mobility functions for the junction and excitation locations. The mobility functions, together with the characteristics of the junction between the subsystems, are then used to determine the response of the global structure and the MPF. In the considered coupled plate structure, MPF expressions are derived for distributed mechanical excitation which is independent of the structure response. However using a similar approach with some modifications excitation by an acoustic plane wave can be considered. Some modifications are required to deal with the latter case are necessary because the forces (acoustic pressure) acting on the structure are dependent on the response of the structure due to the presence of the scattered pressure.

How to decrease pedestrian injuries: conceptual evolutions starting from 137 crash tests.

PubMed

Thollon, Lionel; Jammes, Christian; Behr, Michel; Arnoux, Pierre-Jean; Cavallero, Claude; Brunet, Christian

2007-02-01

The improvement of vulnerable users' protection has become an essential objective for our society. Injury assessments observed in clinical traumatology have led researchers and manufacturers to understand the mechanisms involved and to design safe vehicles (to reduce the severity of pedestrian injuries). In all, 137 crash tests between 1979 and 2004 with postmortal human subjects (PMHS) were performed at the Laboratory of Applied Biomechanics to access pedestrian protection. A retrospective analysis of these experimental tests, pedestrian/car impacts (full scale or subsystems), performed at the laboratory is thus proposed. This document focuses on injury mechanisms investigation on the evolution of the experimental approach, as well as on the vehicles' technological improvements performed by car manufacturers. The analysis of experimental results (injury assessment, kinematics, vehicle deformations, etc.) shows the complexity and variety of injury mechanisms. The injury assessment shows the need to improve lower-limb joints protection, as well as head and spine segments, because of the difficulties of surgical repair of these injuries. Experimental tests contribute to evaluate the automobile safety evolution in the field of pedestrian protection. The main induced car improvements concern considerable efforts on vehicle material behavior and their capacity to dissipate energy during shocks (replacement of the convex rigid bumpers by deformable structures, modification of the windscreen structure). They also concern the suppression of all aggressive structures for the pedestrian (spare wheel initially placed on the front part of the vehicle, protection of the heels of windscreen wiper, etc.).

Mn-modification effects on Nb2O5 structural, optical and vibrational properties

NASA Astrophysics Data System (ADS)

Raba, A. M.; Murillo, E.; Joya, M. R.

2017-12-01

In this study Mn-modification (at 1%, 2.5%, 5% and 10%) on Nb2O5 was carried out through the Pechini method; the annealing temperatures: 400°C, 500°C, 600°C and 700°C, were used to study the thermal stability of the system and the crystalline growth. The crystallization at high temperatures has been investigated because low annealing temperature cannot improve the crystallization and the effect of Mn-modification concentration is worthy of a further investigation. Before annealing the samples were analysed by TGA. The structural analysis through XRD is carried out to study a possible increase of the crystallite size (L) by increasing the Mn concentration; for the samples at 700°C and 1% and 2.5% concentrations, L is increased from 39.81 to 46.45nm while L changes from 32.67 to 35.63 with 5% and 10%, respectively. After Mn-modification the evolution of (100) and (180) peaks Nb2O5 was observed suggesting that they were well defined only until 2.5%. IR and Raman spectroscopies allowed to analyse vibrational modes present in the samples: the IR spectrums for the samples at 400°C, 500°C and 600°C showed a band around 1100cm-1 which can be associated to C-C(νC-C) and C-O(νC-O) vibrations; at 700°C the shoulder was distinguished around 750cm-1 characteristics of the Nb2O5 orthorhombic structure. Vibration modes associated with Nb2O5 were found with the Raman spectroscopy; these become less intense after Mn-modification. The band gap energy was obtained through UV-Vis spectrophotometry which revealed a slight increase at 700°C.

A selective reaction of fructose bisphosphate aldolase with fluorescein isothiocyanate in chicken muscle extracts.

PubMed

Gehring, Andrew G; Ezzell, John L; Lebherz, Herbert G

2008-01-01

The present work describes the selective covalent modification of fructose bisphosphate aldolase in crude extracts of chicken breast muscle by fluorescein 5'-isothiocyanate (5'-FITC) at pH 7.0 and 35 degrees C. The modification was observed after 1 min while no other major soluble protein was labeled even after 30 min. We calculated that ca. one 5'-FITC molecule was incorporated into each aldolase tetramer after a 30 min reaction which resulted in a minimal loss of enzyme activity. The "native" structure of aldolase was required for the selective modification by 5'-FITC since high pH, high temperature, and ionic detergents either inhibited or prevented the reaction of 5'-FITC with aldolase. Certain metabolites (ATP, ADP, CTP, GTP, FBP) and erythrosin B also inhibited the 5'-FITC modification of aldolase. In contrast, F-6-P, AMP, NADH, and NAD(+) as well as free lysine and most importantly, the 6'-isomer of FITC exhibited no competition with 5'-FITC for the labeling of aldolase. Alone, the 6'-isomer of FITC did not exhibit preferential reaction when combined with aldolase. 5'-FITC-labeled and -unlabeled aldolases were not distinguished by their ability to bind to muscle myofibrils (MFs) or by their abilities to refold following reversible denaturation in urea. Structural analysis revealed that 5'-FITC-labeled a tryptic peptide corresponding to residues 112-134 in the primary structure of aldolase, a peptide that does not contain lysine, the amino acid believed to be the primary target of this reagent. Unlike chicken and rabbit muscle aldolases, chicken brain and liver aldolase isoforms along with several other aldolases derived from diverse biological sources did not exhibit this highly selective modification by 5'-FITC. 2008 John Wiley & Sons, Ltd

New capacities and modifications for NASTRAN level 17.5 at DTNSRDC

NASA Technical Reports Server (NTRS)

Hurwitz, M. M.

1980-01-01

Since 1970 DTNSRDC has been modifying NASTRAN to suite various Navy requirements. These modifications include capabilities as well as user conveniences and error corrections. The new features added to NASTRAN Level 17.5 are described. The subject areas of the additions include magnetostatics, piezoelectricity, fluid structure interactions, isoparametric finite elements, and shock design for shipboard equipment.

Ink and Holes: Correlates and Predictive Associations of Body Modification among Adolescents

ERIC Educational Resources Information Center

Dukes, Richard L.; Stein, Judith A.

2011-01-01

We examined correlates and predictive associations of tattoos and body piercings among 1,462 Colorado students in grades 9 to 12. More boys (19%) than girls (17%) reported tattoos, but more girls (42%) than boys (16%) reported piercings (earlobes not included). Older students reported more body modification. Structural equation models showed that…

Large woody debris input and its influence on channel structure in agricultural lands of Southeast Brazil.

PubMed

de Paula, Felipe Rossetti; Ferraz, Silvio Frosini de Barros; Gerhard, Pedro; Vettorazzi, Carlos Alberto; Ferreira, Anderson

2011-10-01

Riparian forests are important for the structure and functioning of stream ecosystems, providing structural components such as large woody debris (LWD). Changes in these forests will cause modifications in the LWD input to streams, affecting their structure. In order to assess the influence of riparian forests changes in LWD supply, 15 catchments (third and fourth order) with riparian forests at different conservation levels were selected for sampling. In each catchment we quantified the abundance, volume and diameter of LWD in stream channels; the number, area and volume of pools formed by LWD and basal area and tree diameter of riparian forest. We found that riparian forests were at a secondary successional stage with predominantly young trees (diameter at breast height <10 cm) in all studied streams. Results showed that basal area and diameter of riparian forest differed between the stream groups (forested and non-forested), but tree density did not differ between groups. Differences were also observed in LWD abundance, volume, frequency of LWD pools with subunits and area and volume of LWD pools. LWD diameter, LWD that form pools diameter and frequency of LWD pools without subunits did not differ between stream groups. Regression analyses showed that LWD abundance and volume, and frequency of LWD pools (with and without subunits) were positively related with the proportion of riparian forest. LWD diameter was not correlated to riparian tree diameter. The frequency of LWD pools was correlated to the abundance and volume of LWD, but characteristics of these pools (area and volume) were not correlated to the diameter of LWD that formed the pools. These results show that alterations in riparian forest cause modifications in the LWD abundance and volume in the stream channel, affecting mainly the structural complexity of these ecosystems (reduction in the number and structural characteristics of LWD pools). Our results also demonstrate that riparian forest conservation actions must consider not only its extension, but also successional stage to guarantee the quantity and quality of LWD necessary to enable the structuring of stream channels.

Surprising Alteration of Antibacterial Activity of 5″-Modified Neomycin against Resistant Bacteria

PubMed Central

Zhang, Jianjun; Chiang, Fang-I; Wu, Long; Czyryca, Przemyslaw Greg; Li, Ding; Chang, Cheng-Wei Tom

2009-01-01

A facile synthetic protocol for the production of neomycin B derivatives with various modifications at the 5″ position has been developed. Structural activity relationship (SAR) against aminoglycoside resistant bacteria equipped with various aminoglycoside-modifying enzymes (AME's) was investigated. Enzymatic and molecular modeling studies reveal that the superb substrate promiscuity of AME's allows the resistant bacteria to cope with diverse structural modifications despite the observation that several derivatives show enhanced antibacterial activity than the parent neomycin. Surprisingly, when testing synthetic neomycin derivatives against other human pathogens, two leads exhibit prominent activity against both Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) that are known to exert high level of resistance against clinically used aminoglycosides. These findings can be extremely useful in developing new aminoglycoside antibiotics against resistant bacteria. Our result also suggests that new biological and antimicrobial activities can be obtained by chemical modifications of old drugs. PMID:19012394

Efficient computational nonlinear dynamic analysis using modal modification response technique

NASA Astrophysics Data System (ADS)

Marinone, Timothy; Avitabile, Peter; Foley, Jason; Wolfson, Janet

2012-08-01

Generally, structural systems contain nonlinear characteristics in many cases. These nonlinear systems require significant computational resources for solution of the equations of motion. Much of the model, however, is linear where the nonlinearity results from discrete local elements connecting different components together. Using a component mode synthesis approach, a nonlinear model can be developed by interconnecting these linear components with highly nonlinear connection elements. The approach presented in this paper, the Modal Modification Response Technique (MMRT), is a very efficient technique that has been created to address this specific class of nonlinear problem. By utilizing a Structural Dynamics Modification (SDM) approach in conjunction with mode superposition, a significantly smaller set of matrices are required for use in the direct integration of the equations of motion. The approach will be compared to traditional analytical approaches to make evident the usefulness of the technique for a variety of test cases.

Post isolation modification of exosomes for nanomedicine applications.

PubMed

Hood, Joshua L

2016-07-01

Exosomes are extracellular nanovesicles. They innately possess ideal structural and biocompatible nanocarrier properties. Exosome components can be engineered at the cellular level. Alternatively, when exosome source cells are unavailable for customized exosome production, exosomes derived from a variety of biological origins can be modified post isolation which is the focus of this article. Modification of exosome surface structures allows for exosome imaging and tracking in vivo. Exosome membranes can be loaded with hydrophobic therapeutics to increase drug stability and efficacy. Hydrophilic therapeutics such as RNA can be encapsulated in exosomes to improve cellular delivery. Despite advances in post isolation exosome modification strategies, many challenges to effectively harnessing their therapeutic potential remain. Future topics of exploration include: matching exosome subtypes with nanomedicine applications, optimizing exosomal nanocarrier formulation and investigating how modified exosomes interface with the immune system. Research into these areas will greatly facilitate personalized exosome-based nanomedicine endeavors.

Post isolation modification of exosomes for nanomedicine applications

PubMed Central

Hood, Joshua L

2016-01-01

Exosomes are extracellular nanovesicles. They innately possess ideal structural and biocompatible nanocarrier properties. Exosome components can be engineered at the cellular level. Alternatively, when exosome source cells are unavailable for customized exosome production, exosomes derived from a variety of biological origins can be modified post isolation which is the focus of this article. Modification of exosome surface structures allows for exosome imaging and tracking in vivo. Exosome membranes can be loaded with hydrophobic therapeutics to increase drug stability and efficacy. Hydrophilic therapeutics such as RNA can be encapsulated in exosomes to improve cellular delivery. Despite advances in post isolation exosome modification strategies, many challenges to effectively harnessing their therapeutic potential remain. Future topics of exploration include: matching exosome subtypes with nanomedicine applications, optimizing exosomal nanocarrier formulation and investigating how modified exosomes interface with the immune system. Research into these areas will greatly facilitate personalized exosome-based nanomedicine endeavors. PMID:27348448

Numerical modeling analysis of stress transfer modification concepts for deep longwall mines. Report of investigations/1995

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

Vandergrift, T.L.; Jude, C.V.

1995-12-31

This U.S. Bureau of Mines (USBM) report evaluates three stress-transfer-modification concepts for their potential in reducing longwall gate road stresses and closures. In each of the three concepts--packwalling, gob infilling, and entry filling--support structures are constructed on the headgate side of the panel parallel with or inby the face line. When the headgate becomes the tailgate of the adjacent panel, these structures are in place to accept stresses transferred from the mined-out panel. Using the USBM nonlinear boundary-element program MULSIM/NL, baseline models of typical longwall stress transfer behavior were developed for both intermediate depth and deep mining conditions. These modelsmore » were verified by comparing model results with field measurements and observations. The stress-transfer-modification concepts were then incorporated into the deep baseline model to quantify the effects of each concept on tailgate closure.« less

Approximate techniques of structural reanalysis

NASA Technical Reports Server (NTRS)

Noor, A. K.; Lowder, H. E.

1974-01-01

A study is made of two approximate techniques for structural reanalysis. These include Taylor series expansions for response variables in terms of design variables and the reduced-basis method. In addition, modifications to these techniques are proposed to overcome some of their major drawbacks. The modifications include a rational approach to the selection of the reduced-basis vectors and the use of Taylor series approximation in an iterative process. For the reduced basis a normalized set of vectors is chosen which consists of the original analyzed design and the first-order sensitivity analysis vectors. The use of the Taylor series approximation as a first (initial) estimate in an iterative process, can lead to significant improvements in accuracy, even with one iteration cycle. Therefore, the range of applicability of the reanalysis technique can be extended. Numerical examples are presented which demonstrate the gain in accuracy obtained by using the proposed modification techniques, for a wide range of variations in the design variables.

Structural basis for m7G recognition and 2'-O-methyl discrimination in capped RNAs by the innate immune receptor RIG-I

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

Devarkar, Swapnil C.; Wang, Chen; Miller, Matthew T.

The cytosolic innate immune receptor Retinoic Acid Inducible Gene-I (RIG-I) is the principal detector of pathogenic RNAs carrying a 5'-triphosphate (5'ppp). Self RNAs like mRNAs evade recognition by RIG-I due to posttranscriptional modifications like 5'-end capping with 7-methyl guanosine (m7G) and 2'-O-methylation of 5'-end nucleotides. Viruses have also evolved mechanisms to mimic these modifications, which in part is believed to aid in immune evasion. Currently, it is unclear how these modifications modulate RIG-I recognition. This paper provides structural and mechanistic insights into the roles of the m7G cap and 2'-O-methylation in RIG-I evasion. We show that RIG-I accommodates the m7Gmore » base while maintaining the 5'ppp contacts and can recognize Cap-0 RNAs but not Cap-1.« less

Modification of chemical reactivity of enzymatic hydrolysis lignin by ultrasound treatment in dilute alkaline solutions.

PubMed

Ma, Zhuoming; Li, Shujun; Fang, Guizhen; Patil, Nikhil; Yan, Ning

2016-12-01

In this study, we have explored various ultrasound treatment conditions for structural modification of enzymatic hydrolysis lignin (EHL) for enhanced chemical reactivity. The key structural modifications were characterized by using a combination of analytical methods, including, Fourier Transform-Infrared spectroscopy (FTIR), Proton Nuclear Magnetic Resonance ( 1 H NMR), Gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS), and Folin-Ciocalteu (F-C) method. Chemical reactivity of the modified EHL samples was determined by both 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and their reactivity towards formaldehyde. It was observed that the modified EHL had a higher phenolic hydroxyl group content, a lower molecular weight, a higher reactivity towards formaldehyde, and a greater antioxidant property. The higher reactivity demonstrated by the samples after treatment suggesting that ultrasound is a promising method for modifying enzymatic hydrolysis lignin for value-added applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Ice cream structure modification by ice-binding proteins.

PubMed

Kaleda, Aleksei; Tsanev, Robert; Klesment, Tiina; Vilu, Raivo; Laos, Katrin

2018-04-25

Ice-binding proteins (IBPs), also known as antifreeze proteins, were added to ice cream to investigate their effect on structure and texture. Ice recrystallization inhibition was assessed in the ice cream mixes using a novel accelerated microscope assay and the ice cream microstructure was studied using an ice crystal dispersion method. It was found that adding recombinantly produced fish type III IBPs at a concentration 3 mg·L -1 made ice cream hard and crystalline with improved shape preservation during melting. Ice creams made with IBPs (both from winter rye, and type III IBP) had aggregates of ice crystals that entrapped pockets of the ice cream mixture in a rigid network. Larger individual ice crystals and no entrapment in control ice creams was observed. Based on these results a model of ice crystals aggregates formation in the presence of IBPs was proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural aspects of the solvation shell of lysine and acetylated lysine: A Car-Parrinello and classical molecular dynamics investigation

NASA Astrophysics Data System (ADS)

Carnevale, V.; Raugei, S.

2009-12-01

Lysine acetylation is a post-translational modification, which modulates the affinity of protein-protein and/or protein-DNA complexes. Its crucial role as a switch in signaling pathways highlights the relevance of charged chemical groups in determining the interactions between water and biomolecules. A great effort has been recently devoted to assess the reliability of classical molecular dynamics simulations in describing the solvation properties of charged moieties. In the spirit of these investigations, we performed classical and Car-Parrinello molecular dynamics simulations on lysine and acetylated-lysine in aqueous solution. A comparative analysis between the two computational schemes is presented with a focus on the first solvation shell of the charged groups. An accurate structural analysis unveils subtle, yet statistically significant, differences which are discussed in connection to the significant electronic density charge transfer occurring between the solute and the surrounding water molecules.

Temporal genetic stability of Stegomyia aegypti (= Aedes aegypti) populations.

PubMed

Gloria-Soria, A; Kellner, D A; Brown, J E; Gonzalez-Acosta, C; Kamgang, B; Lutwama, J; Powell, J R

2016-06-01

The mosquito Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) is the primary vector of viruses that cause yellow fever, dengue and Chikungunya fever. In the absence of effective vaccines, the reduction of these diseases relies on vector control strategies. The success of these strategies is tightly linked to the population dynamics of target populations. In the present study, 14 collections from St. aegypti populations separated by periods of 1-13 years were analysed to determine their temporal genetic stability. Although temporal structure is discernible in most populations, the degree of temporal differentiation is dependent on the population and does not obscure the geographic structure of the various populations. The results suggest that performing detailed studies in the years prior to and after population reduction- or modification-based control interventions at each target field site may be useful in assessing the probability of success. © 2016 The Royal Entomological Society.

UV-POSIT: Web-Based Tools for Rapid and Facile Structural Interpretation of Ultraviolet Photodissociation (UVPD) Mass Spectra

NASA Astrophysics Data System (ADS)

Rosenberg, Jake; Parker, W. Ryan; Cammarata, Michael B.; Brodbelt, Jennifer S.

2018-04-01

UV-POSIT (Ultraviolet Photodissociation Online Structure Interrogation Tools) is a suite of web-based tools designed to facilitate the rapid interpretation of data from native mass spectrometry experiments making use of 193 nm ultraviolet photodissociation (UVPD). The suite includes four separate utilities which assist in the calculation of fragment ion abundances as a function of backbone cleavage sites and sequence position; the localization of charge sites in intact proteins; the calculation of hydrogen elimination propensity for a-type fragment ions; and mass-offset searching of UVPD spectra to identify unknown modifications and assess false positive fragment identifications. UV-POSIT is implemented as a Python/Flask web application hosted at http://uv-posit.cm.utexas.edu. UV-POSIT is available under the MIT license, and the source code is available at https://github.com/jarosenb/UV_POSIT. [Figure not available: see fulltext.

UV-POSIT: Web-Based Tools for Rapid and Facile Structural Interpretation of Ultraviolet Photodissociation (UVPD) Mass Spectra.

PubMed

Rosenberg, Jake; Parker, W Ryan; Cammarata, Michael B; Brodbelt, Jennifer S

2018-06-01

UV-POSIT (Ultraviolet Photodissociation Online Structure Interrogation Tools) is a suite of web-based tools designed to facilitate the rapid interpretation of data from native mass spectrometry experiments making use of 193 nm ultraviolet photodissociation (UVPD). The suite includes four separate utilities which assist in the calculation of fragment ion abundances as a function of backbone cleavage sites and sequence position; the localization of charge sites in intact proteins; the calculation of hydrogen elimination propensity for a-type fragment ions; and mass-offset searching of UVPD spectra to identify unknown modifications and assess false positive fragment identifications. UV-POSIT is implemented as a Python/Flask web application hosted at http://uv-posit.cm.utexas.edu . UV-POSIT is available under the MIT license, and the source code is available at https://github.com/jarosenb/UV_POSIT . Graphical Abstract.

Nanoscale dose deposition in cell structures under X-ray irradiation treatment assisted with nanoparticles: An analytical approach to the relative biological effectiveness.

PubMed

Melo-Bernal, W; Chernov, V; Chernov, G; Barboza-Flores, M

2018-08-01

In this study, an analytical model for the assessment of the modification of cell culture survival under ionizing radiation assisted with nanoparticles (NPs) is presented. The model starts from the radial dose deposition around a single NP, which is used to describe the dose deposition in a cell structure with embedded NPs and, in turn, to evaluate the number of lesions formed by ionizing radiation. The model is applied to the calculation of relative biological effectiveness values for cells exposed to 0.5mg/g of uniformly dispersed NPs with a radius of 10nm made of Fe, I, Gd, Hf, Pt and Au and irradiated with X-rays of energies 20keV higher than the element K-shell binding energy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Materials and structural aspects of advanced gas-turbine helicopter engines

NASA Technical Reports Server (NTRS)

Freche, J. C.; Acurio, J.

1979-01-01

The key to improved helicopter gas turbine engine performance lies in the development of advanced materials and advanced structural and design concepts. The modification of the low temperature components of helicopter engines (such as the inlet particle separator), the introduction of composites for use in the engine front frame, the development of advanced materials with increased use-temperature capability for the engine hot section, can result in improved performance and/or decreased engine maintenance cost. A major emphasis in helicopter engine design is the ability to design to meet a required lifetime. This, in turn, requires that the interrelated aspects of higher operating temperatures and pressures, cooling concepts, and environmental protection schemes be integrated into component design. The major material advances, coatings, and design life-prediction techniques pertinent to helicopter engines are reviewed; the current state-of-the-art is identified; and when appropriate, progress, problems, and future directions are assessed.

Chemical modification of botryosphaeran: structural characterization and anticoagulant activity of a water-soluble sulfonated (1-->3)(1-->6)-β-D-glucan.

PubMed

Brandi, Jamile; Oliveira, Éder C; Monteiro, Nilson; Vasconcelos, Ana Flora D; Dekker, Robert F H; Barbosa, Aneli M; Silveira, Joana L M; Mourão, Paulo A S; Corradi da Silva, Maria de Lourdes

2011-10-01

The exopolysaccharide botryosphaeran (EPS(GLC); a (1--> 3)(1-->6)-β-D-glucan from Botryosphaeria rhodina MAMB- 05) was sulfonated to produce a water-soluble fraction (EPS(GLC)-S) using pyridine and chlorosulfonic acid in formamid. This procedure was then repeated twice to produce another fraction (EPSGLC-RS) with a higher degree of substitution (DS, 1.64). The purity of each botryosphaeran sample (unsulfonated and sulfonated) was assessed by gel filtration chromatography (Sepharose CL-4B), where each polysaccharide was eluted as a single symmetrical peak. The structures of the sulfonated and re-sulfonated botryosphaerans were investigated using ultraviolet-visible (UV-Vis), Fourier-transform infrared (FT-IR), and (13)C nuclear magnetic resonance ((13)C NMR) spectroscopies. EPS(GLC) and EPS(GLC)-RS were also assayed for anticoagulation activity, and EPS(GLC)-RS was identified as an anticoagulant.

Acclimation of isoprene emission and photosynthesis to growth temperature in hybrid aspen: resolving structural and physiological controls.

PubMed

Rasulov, Bahtijor; Bichele, Irina; Hüve, Katja; Vislap, Vivian; Niinemets, Ülo

2015-04-01

Acclimation of foliage to growth temperature involves both structural and physiological modifications, but the relative importance of these two mechanisms of acclimation is poorly known, especially for isoprene emission responses. We grew hybrid aspen (Populus tremula x P. tremuloides) under control (day/night temperature of 25/20 °C) and high temperature conditions (35/27 °C) to gain insight into the structural and physiological acclimation controls. Growth at high temperature resulted in larger and thinner leaves with smaller and more densely packed chloroplasts and with lower leaf dry mass per area (MA). High growth temperature also led to lower photosynthetic and respiration rates, isoprene emission rate and leaf pigment content and isoprene substrate dimethylallyl diphosphate pool size per unit area, but to greater stomatal conductance. However, all physiological characteristics were similar when expressed per unit dry mass, indicating that the area-based differences were primarily driven by MA. Acclimation to high temperature further increased heat stability of photosynthesis and increased activation energies for isoprene emission and isoprene synthase rate constant. This study demonstrates that temperature acclimation of photosynthetic and isoprene emission characteristics per unit leaf area were primarily driven by structural modifications, and we argue that future studies investigating acclimation to growth temperature must consider structural modifications. © 2014 John Wiley & Sons Ltd.

Derivatization of DNAs with Selenium at 6-Position of Guanine for Function and Crystal Structure Studies

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

Salon, J.; Jiang, J; Sheng, J

2008-01-01

To investigate nucleic acid base pairing and stacking via atom-specific mutagenesis and crystallography, we have synthesized for the first time the 6-Se-deoxyguanosine phosphoramidite and incorporated it into DNAs via solid-phase synthesis with a coupling yield over 97%. We found that the UV absorption of the Se-DNAs red-shifts over 100 nm to 360 nm ({Epsilon} = 2.3 x 10{sup 4} M{sup -1} cm{sup -1}), the Se-DNAs are yellow colored, and this Se modification is relatively stable in water and at elevated temperature. Moreover, we successfully crystallized a ternary complex of the Se-G-DNA, RNA and RNase H. The crystal structure determination andmore » analysis reveal that the overall structures of the native and Se-modified nucleic acid duplexes are very similar, the selenium atom participates in a Se-mediated hydrogen bond (Se H-N), and the {sup Se}G and C form a base pair similar to the natural G-C pair though the Se-modification causes the base-pair to shift (approximately 0.3 {angstrom}). Our biophysical and structural studies provide new insights into the nucleic acid flexibility, duplex recognition and stability. Furthermore, this novel selenium modification of nucleic acids can be used to investigate chemogenetics and structure of nucleic acids and their protein complexes.« less

PTFE-nanocomposites structure and wear-resistance changing in various methods of structural modification

NASA Astrophysics Data System (ADS)

Mashkov, Yu K.; Ruban, A. S.; Rogachev, E. A.; Chemisenko, O. V.

2018-01-01

Conditions of polymer materials usage containing nanoelements as modifiers significantly affect the requirements for their physic-mechanical and tribological properties. However, the mechanisms of nanoparticles effect to the polymers tribotechnical properties have not been studied enough. The article aim is to analyze the results of studying polytetrafluoroethylene modified with cryptocrystalline graphite and silicon dioxide and to determine the effectiveness of the modification methods used and methods for further improving filled PTFE mechanical and tribotechnical properties. The effect of modifiers to PCM supramolecular structure was analyzed with SEM methods. The results of modifying the PCM samples surface by depositing a copper film with ion-vacuum deposition methods and changing the structural-phase composition and tribological characteristics are considered. The findings make possible to characterize the physicochemical processes under frictional interaction in metal polymer tribosystems.

A new triclinic modification of the pyrochlore-type KOs{sub 2}O{sub 6} superconductor

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

Katrych, S.; Gu, Q.F.; Bukowski, Z.

2009-03-15

A new modification of KOs{sub 2}O{sub 6}, the representative of a new structural type (Pearson symbol aP18, a=5.5668(1) A, b=6.4519(2) A, c=7.2356(2) A, {alpha}=65.377(3){sup o}, {beta}=70.572(3){sup o}, {gamma}=75.613(2){sup o} space group P-1, no. 2 was synthesized employing high pressure technique. Its structure was determined by single-crystal X-ray diffraction. The structure can be described as two OsO{sub 6} octahedral chains relating to each other through inversion and forming big voids with K atoms inside. Quantum chemical calculations were performed on the novel compound and structurally related cubic compound. High-pressure X-ray study showed that cubic KOs{sub 2}O{sub 6} phase was stable upmore » to 32.5(2) GPa at room temperature. - Graphical abstract: A new modification of KOs{sub 2}O{sub 6}, the representative of a new structural type (Pearson symbol aP18, a=5.5668(1) A, b=6.4519(2) A, c=7.2356(2) A, {alpha}=65.377(3){sup o}, {beta}=70.572(3){sup o}, {gamma}=75.613(2){sup o} space group P-1, no. 2 was synthesized employing high pressure technique. The structure can be described as two OsO{sub 6} octahedral chains relating to each other through inversion and forming big voids with K atoms inside.« less

Modified Amber Force Field Correctly Models the Conformational Preference for Tandem GA pairs in RNA

PubMed Central

2015-01-01

Molecular mechanics with all-atom models was used to understand the conformational preference of tandem guanine-adenine (GA) noncanonical pairs in RNA. These tandem GA pairs play important roles in determining stability, flexibility, and structural dynamics of RNA tertiary structures. Previous solution structures showed that these tandem GA pairs adopt either imino (cis Watson–Crick/Watson–Crick A-G) or sheared (trans Hoogsteen/sugar edge A-G) conformations depending on the sequence and orientation of the adjacent closing base pairs. The solution structures (GCGGACGC)2 [Biochemistry, 1996, 35, 9677–9689] and (GCGGAUGC)2 [Biochemistry, 2007, 46, 1511–1522] demonstrate imino and sheared conformations for the two central GA pairs, respectively. These systems were studied using molecular dynamics and free energy change calculations for conformational changes, using umbrella sampling. For the structures to maintain their native conformations during molecular dynamics simulations, a modification to the standard Amber ff10 force field was required, which allowed the amino group of guanine to leave the plane of the base [J. Chem. Theory Comput., 2009, 5, 2088–2100] and form out-of-plane hydrogen bonds with a cross-strand cytosine or uracil. The requirement for this modification suggests the importance of out-of-plane hydrogen bonds in stabilizing the native structures. Free energy change calculations for each sequence demonstrated the correct conformational preference when the force field modification was used, but the extent of the preference is underestimated. PMID:24803859

Progress in aminosugar derived asymmetric organocatalysis.

PubMed

Agarwal, Jyoti

2016-11-22

In the last decade aminosugars, especially d-glucoamine based organocatalysts, have been applied to catalyze various asymmetric reactions such as aldol reactions, Michael addition, Strecker reactions, Biginelli reactions, epoxidation, fluorination, and imine reduction, and for the synthesis of various biologically important molecules such as 3-alkylnitro-2-hydroxynaphthoquinones, trans-dihydrobenzofurans etc. Immense growth has been also observed in the structural modification of aminosugar based organocatalysts to obtain the best results from them. This review sheds light on such organocatalytic transformations reported in last the decade including the effect of the structural modification of sugar amines on their catalytic efficiency and the stereoselectivity of the reaction.

Structures, properties, modifications, and uses of oat starch.

PubMed

Zhu, Fan

2017-08-15

There has been increasing interest to utilise oats and their components to formulate healthy food products. Starch is the major component of oat kernels and may account up to 60% of the dry weight. Starch properties may greatly determine the product quality. As a by-product of oat processing and fractionation, the starch may also be utilised for food and non-food applications. This mini-review updates the recent advances in the isolation, chemical and granular structures, physicochemical properties, chemical and physical modifications, and food and non-food uses of oat starch. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural and Functional Coordination of DNA and Histone Methylation

PubMed Central

Cheng, Xiaodong

2014-01-01

One of the most fundamental questions in the control of gene expression in mammals is how epigenetic methylation patterns of DNA and histones are established, erased, and recognized. This central process in controlling gene expression includes coordinated covalent modifications of DNA and its associated histones. This article focuses on structural aspects of enzymatic activities of histone (arginine and lysine) methylation and demethylation and functional links between the methylation status of the DNA and histones. An interconnected network of methyltransferases, demethylases, and accessory proteins is responsible for changing or maintaining the modification status of specific regions of chromatin. PMID:25085914

Identifying Novel Molecular Structures for Advanced Melanoma by Ligand-Based Virtual Screening

PubMed Central

Wang, Zhao; Lu, Yan; Seibel, William; Miller, Duane D.; Li, Wei

2009-01-01

We recently discovered a new class of thiazole analogs that are highly potent against melanoma cells. To expand the structure-activity relationship study and to explore potential new molecular scaffolds, we performed extensive ligand-based virtual screening against a compound library containing 342,910 small molecules. Two different approaches of virtual screening were carried out using the structure of our lead molecule: 1) connectivity-based search using Scitegic Pipeline Pilot from Accelerys and 2) molecular shape similarity search using Schrodinger software. Using a testing compound library, both approaches can rank similar compounds very high and rank dissimilar compounds very low, thus validating our screening methods. Structures identified from these searches were analyzed, and selected compounds were tested in vitro to assess their activity against melanoma cancer cell lines. Several molecules showed good anticancer activity. While none of the identified compounds showed better activity than our lead compound, they provided important insight into structural modifications for our lead compound and also provided novel platforms on which we can optimize new classes of anticancer compounds. One of the newly synthesized analogs based on this virtual screening has improved potency and selectivity against melanoma. PMID:19445498

14 CFR 1216.203 - Definition of key terms.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Floodplain and Wetlands Management § 1216.203 Definition of key terms. (a) Action—any NASA activity including... buildings, structures and utility items, marine structures, bridges and other land development items, such... wetlands. (i) Floodproofing—the modification of individual structures and facilities, their sites, and...

Salvage of failed protein targets by reductive alkylation.

PubMed

Tan, Kemin; Kim, Youngchang; Hatzos-Skintges, Catherine; Chang, Changsoo; Cuff, Marianne; Chhor, Gekleng; Osipiuk, Jerzy; Michalska, Karolina; Nocek, Boguslaw; An, Hao; Babnigg, Gyorgy; Bigelow, Lance; Joachimiak, Grazyna; Li, Hui; Mack, Jamey; Makowska-Grzyska, Magdalena; Maltseva, Natalia; Mulligan, Rory; Tesar, Christine; Zhou, Min; Joachimiak, Andrzej

2014-01-01

The growth of diffraction-quality single crystals is of primary importance in protein X-ray crystallography. Chemical modification of proteins can alter their surface properties and crystallization behavior. The Midwest Center for Structural Genomics (MCSG) has previously reported how reductive methylation of lysine residues in proteins can improve crystallization of unique proteins that initially failed to produce diffraction-quality crystals. Recently, this approach has been expanded to include ethylation and isopropylation in the MCSG protein crystallization pipeline. Applying standard methods, 180 unique proteins were alkylated and screened using standard crystallization procedures. Crystal structures of 12 new proteins were determined, including the first ethylated and the first isopropylated protein structures. In a few cases, the structures of native and methylated or ethylated states were obtained and the impact of reductive alkylation of lysine residues was assessed. Reductive methylation tends to be more efficient and produces the most alkylated protein structures. Structures of methylated proteins typically have higher resolution limits. A number of well-ordered alkylated lysine residues have been identified, which make both intermolecular and intramolecular contacts. The previous report is updated and complemented with the following new data; a description of a detailed alkylation protocol with results, structural features, and roles of alkylated lysine residues in protein crystals. These contribute to improved crystallization properties of some proteins.

Salvage of Failed Protein Targets by Reductive Alkylation

PubMed Central

Tan, Kemin; Kim, Youngchang; Hatzos-Skintges, Catherine; Chang, Changsoo; Cuff, Marianne; Chhor, Gekleng; Osipiuk, Jerzy; Michalska, Karolina; Nocek, Boguslaw; An, Hao; Babnigg, Gyorgy; Bigelow, Lance; Joachimiak, Grazyna; Li, Hui; Mack, Jamey; Makowska-Grzyska, Magdalena; Maltseva, Natalia; Mulligan, Rory; Tesar, Christine; Zhou, Min; Joachimiak, Andrzej

2014-01-01

The growth of diffraction-quality single crystals is of primary importance in protein X-ray crystallography. Chemical modification of proteins can alter their surface properties and crystallization behavior. The Midwest Center for Structural Genomics (MCSG) has previously reported how reductive methylation of lysine residues in proteins can improve crystallization of unique proteins that initially failed to produce diffraction-quality crystals. Recently, this approach has been expanded to include ethylation and isopropylation in the MCSG protein crystallization pipeline. Applying standard methods, 180 unique proteins were alkylated and screened using standard crystallization procedures. Crystal structures of 12 new proteins were determined, including the first ethylated and the first isopropylated protein structures. In a few cases, the structures of native and methylated or ethylated states were obtained and the impact of reductive alkylation of lysine residues was assessed. Reductive methylation tends to be more efficient and produces the most alkylated protein structures. Structures of methylated proteins typically have higher resolution limits. A number of well-ordered alkylated lysine residues have been identified, which make both intermolecular and intramolecular contacts. The previous report is updated and complemented with the following new data; a description of a detailed alkylation protocol with results, structural features, and roles of alkylated lysine residues in protein crystals. These contribute to improved crystallization properties of some proteins. PMID:24590719

The development of a supportive care needs assessment tool for Indigenous people with cancer

PubMed Central

2012-01-01

Background Little is known about the supportive care needs of Indigenous people with cancer and to date, existing needs assessment tools have not considered cultural issues for this population. We aimed to adapt an existing supportive care needs assessment tool for use with Indigenous Australians with cancer. Methods Face-to-face interviews with Indigenous cancer patients (n = 29) and five focus groups with Indigenous key-informants (n = 23) were conducted to assess the face and content validity, cultural acceptability, utility and relevance of the Supportive Care Needs Survey - Short Form 34 (SCNS-SF34) for use with Indigenous patients with cancer. Results All items from the SCNS-SF34 were shortened and changed to use more appropriate language (e.g. the word 'anxiety' was substituted with 'worry'). Seven questions were omitted (e.g. items on death and future considerations) as they were deemed culturally inappropriate or irrelevant and 12 items were added (e.g. accessible transport). Optional instructions were added before the sexual items. The design and response format of the SCNS-SF34 was modified to make it easier to use for Indigenous cancer patients. Given the extensive modifications to the SCNS-SF34 and the liklihood of a different factor structure we consider this tool to be a new tool rather than a modification. The Supportive care needs assessment tool for Indigenous people (SCNAT-IP) shows promising face and content validity and will be useful in informing services where they need to direct their attention for these patients. Conclusions Indigenous people with cancer have language, customs and specific needs that are not accommodated within the standard SCNS-SF34. Our SCNAT-IP improves acceptability, relevance and face validity for Indigenous-specific concerns. Our SCNAT-IP will allow screening for supportive care needs that are specific to Indigenous cancer patients' and greatly inform targeted policy development and practice. PMID:22817614

Environmental Modifications and 2-Year Measured and Self-reported Stair-Use: A Worksite Randomized Trial

PubMed Central

Linde, Jennifer A.; Cousins, Julie M.; Jeffery, Robert W.

2014-01-01

Environmental modifications have been shown to increase short-term stair use, longer-term success is unclear. This study assessed the 2-year effectiveness of an environmental intervention promoting worksite stair use. We assessed stair use at work by means of self-reports and infrared beam counters (which send a safe and invisible beam of infrared light from one side of a stairwell to a reflector on the other side; when an individual uses the stairs, the infrared beam is disrupted and an instance of stair use is recorded) at six worksites (three intervention, three control) in a group randomized, controlled worksite weight-gain prevention trial in Minneapolis/St. Paul, MN. Intervention modifications were signs encouraging stair use, music, and art posters in stairwells. We collected data before environmental modifications (2006–2007) and at the end of the 2-year intervention (2008–2009). The intervention had a significant positive effect on stair use measured both objectively and via self-report, with greatest increases reported among those participants who used the stairs least at baseline. Following 2-years of continuously-maintained stairwell modifications, increases in both objectively-measured and self-reported stair use were significantly larger at intervention than control worksites. Study findings suggest that the positive impact of environmental modifications on stair use persist over a longer time period than has been previously demonstrated. Results also indicate that infrequent stair users may be most amenable to the behavior changes encouraged by these environmental enhancements. PMID:23979097

Mapping of ribosomal 23S ribosomal RNA modifications in Clostridium sporogenes.

PubMed

Kirpekar, Finn; Hansen, Lykke H; Mundus, Julie; Tryggedsson, Stine; Teixeira Dos Santos, Patrícia; Ntokou, Eleni; Vester, Birte

2018-06-27

All organisms contain RNA modifications in their ribosomal RNA (rRNA), but the importance, positions and exact function of these are still not fully elucidated. Various functions such as stabilising structures, controlling ribosome assembly and facilitating interactions have been suggested and in some cases substantiated. Bacterial rRNA contains much fewer modifications than eukaryotic rRNA. The rRNA modification patterns in bacteria differ from each other, but too few organisms have been mapped to draw general conclusions. This study maps 23S ribosomal RNA modifications in Clostridium sporogenes that can be characterised as a non-toxin producing Clostridium botulinum. Clostridia are able to sporulate and thereby survive harsh conditions, and are in general considered to be resilient to antibiotics. Selected regions of the 23S rRNA were investigated by mass spectrometry and by primer extension analysis to pinpoint modified sites and the nature of the modifications. Apparently, C. sporogenes 23S rRNA contains few modifications compared to other investigated bacteria. No modifications were identified in domain II and III of 23S rRNA. Three modifications were identified in domain IV, all of which have also been found in other organisms. Two unusual modifications were identified in domain V, methylated dihydrouridine at position U2449 and dihydrouridine at position U2500 (Escherichia coli numbering), in addition to four previously known modified positions. The enzymes responsible for the modifications were searched for in the C. sporogenes genome using BLAST with characterised enzymes as query. The search identified genes potentially coding for RNA modifying enzymes responsible for most of the found modifications.

Selective Modification of Chitin and Chitosan: En Route to Tailored Oligosaccharides.

PubMed

Carvalho, Luísa C R; Queda, Fausto; Santos, Cátia V Almeida; Marques, M Manuel B

2016-12-19

Chitin and chitosan are attractive biopolymers with enormous structural possibilities for chemical modification, creating platforms for new chemical entities with a broad scope of applications, ranging from material science to medicine. During the last few years, incredible efforts have been dedicated to the regioselective modification of these biopolymers paving the way for improved properties and tailored activities. Herein, the most recent advances in chitin/chitosan regioselective modification, reaction conditions, selectivity, and the impact on its applications are highlighted. Moreover, the recent focus on chitooligosaccharides, their regioselective and chemoselective functionalization, as well as their role in biological studies, including molecular recognition with several biological targets are also covered. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advanced Maillard reaction end products are associated with Alzheimer disease pathology.

PubMed Central

Smith, M A; Taneda, S; Richey, P L; Miyata, S; Yan, S D; Stern, D; Sayre, L M; Monnier, V M; Perry, G

1994-01-01

During aging long-lived proteins accumulate specific post-translational modifications. One family of modifications, termed Maillard reaction products, are initiated by the condensation between amino groups of proteins and reducing sugars. Protein modification by the Maillard reaction is associated with crosslink formation, decreased protein solubility, and increased protease resistance. Here, we present evidence that the characteristic pathological structures associated with Alzheimer disease contain modifications typical of advanced Maillard reaction end products. Specifically, antibodies against two Maillard end products, pyrraline and pentosidine, immunocytochemically label neurofibrillary tangles and senile plaques in brain tissue from patients with Alzheimer disease. In contrast, little or no staining is observed in apparently healthy neurons of the same brain. The Maillard-reaction-related modifications described herein could account for the biochemical and insolubility properties of the lesions of Alzheimer disease through the formation of protein crosslinks. Images PMID:8202552

Epigenomics, Pharmacoepigenomics, and Personalized Medicine in Cervical Cancer.

PubMed

Kabekkodu, Shama Prasada; Chakrabarty, Sanjiban; Ghosh, Supriti; Brand, Angela; Satyamoorthy, Kapaettu

2017-01-01

Epigenomics encompasses the study of genome-wide changes in DNA methylation, histone modifications and noncoding RNAs leading to altered transcription, chromatin structure, and posttranscription RNA processing, respectively, resulting in an altered rate of gene expression. The role of epigenetic modifications facilitating human diseases is well established. Previous studies have identified histone and cytosine code during normal and pathological conditions with special emphasis on how these modifications regulate transcriptional events. Recent studies have also mapped these epigenetic modification and pathways leading to carcinogenesis. Discovery of drugs that target proteins/enzymes in the epigenetic pathways may provide better therapeutic opportunities, and identification of such modulators for DNA methylation, histone modifications, and expression of noncoding RNAs for several cancer types is underway. In this review, we provide a detailed description of recent developments in the field of epigenetics and its impact on personalized medicine to manage cervical cancer. © 2017 S. Karger AG, Basel.

Improving the Dynamic Characteristics of Body-in-White Structure Using Structural Optimization

PubMed Central

Yahaya Rashid, Aizzat S.; Mohamed Haris, Sallehuddin; Alias, Anuar

2014-01-01

The dynamic behavior of a body-in-white (BIW) structure has significant influence on the noise, vibration, and harshness (NVH) and crashworthiness of a car. Therefore, by improving the dynamic characteristics of BIW, problems and failures associated with resonance and fatigue can be prevented. The design objectives attempt to improve the existing torsion and bending modes by using structural optimization subjected to dynamic load without compromising other factors such as mass and stiffness of the structure. The natural frequency of the design was modified by identifying and reinforcing the structure at critical locations. These crucial points are first identified by topology optimization using mass and natural frequencies as the design variables. The individual components obtained from the analysis go through a size optimization step to find their target thickness of the structure. The thickness of affected regions of the components will be modified according to the analysis. The results of both optimization steps suggest several design modifications to achieve the target vibration specifications without compromising the stiffness of the structure. A method of combining both optimization approaches is proposed to improve the design modification process. PMID:25101312

The Modification of Biocellular Chemical Reactions by Environmental Physicochemicals

NASA Astrophysics Data System (ADS)

Ishido, M.

Environmental risk factors affect human biological system to different extent from modification of biochemical reaction to cellular catastrophe. There are considerable public concerns about electromagnetic fields and endocrine disruptors. Their risk assessments have not been fully achieved because of their scientific uncertainty: electromagnetic fields just modify the bioreaction in the restricted cells and endocrine disruptors are quite unique in that their expression is dependent on the exposure periods throughout a life. Thus, we here describe their molecular characterization to establish the new risk assessments for environmental physicochemicals.

Calyx{trademark} EA implementation at AECB

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

NONE

1997-12-31

This report describes a project to examine the applicability of a knowledge-based decision support software for environmental assessment (Calyx) to assist the Atomic Energy Control Board in environmental screenings, assessment, management, and database searches. The report begins with background on the Calyx software and then reviews activities with regard to modification of the Calyx knowledge base for application to the nuclear sector. This is followed by lists of standard activities handled by the software and activities specific to the Board; the hierarchy of environmental components developed for the Board; details of impact rules that describe the conditions under which environmentalmore » impacts will occur (the bulk of the report); information on mitigation and monitoring rules and on instance data; and considerations for future work on implementing Calyx at the Board. Appendices include an introduction to expert systems and an overview of the Calyx knowledge base structure.« less

[Modifications in treatment of tetanus and prognosis--observations from the Cracow Department of Infectious Diseases].

PubMed

Garlicki, A; Caban, J; Bociaga-Jasik, M; Kluba-Wojewoda, U; Krukowiecki, J

1999-01-01

The assessment of modifications in the tetanus treatment, which included using metronidazol and midazolam instead penicillin and diazepam, was presented. According to our own observations and previous investigations, mentioned above changes in the tetanus therapy improve survival rate, reduce psychiatric disturbances and shorten hospitalisation time.

Synthesis, base pairing and structure studies of geranylated RNA

PubMed Central

Wang, Rui; Vangaveti, Sweta; Ranganathan, Srivathsan V.; Basanta-Sanchez, Maria; Haruehanroengra, Phensinee; Chen, Alan; Sheng, Jia

2016-01-01

Natural RNAs utilize extensive chemical modifications to diversify their structures and functions. 2-Thiouridine geranylation is a special hydrophobic tRNA modification that has been discovered very recently in several bacteria, such as Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa and Salmonella Typhimurium. The geranylated residues are located in the first anticodon position of tRNAs specific for lysine, glutamine and glutamic acid. This big hydrophobic terpene functional group affects the codon recognition patterns and reduces frameshifting errors during translation. We aimed to systematically study the structure, function and biosynthesis mechanism of this geranylation pathway, as well as answer the question of why nature uses such a hydrophobic modification in hydrophilic RNA systems. Recently, we have synthesized the deoxy-analog of S-geranyluridine and showed the geranylated T-G pair is much stronger than the geranylated T-A pair and other mismatched pairs in the B-form DNA duplex context, which is consistent with the observation that the geranylated tRNAGluUUC recognizes GAG more efficiently than GAA. In this manuscript we report the synthesis and base pairing specificity studies of geranylated RNA oligos. We also report extensive molecular simulation studies to explore the structural features of the geranyl group in the context of A-form RNA and its effect on codon–anticodon interaction during ribosome binding. PMID:27307604

Structural and Functional Characterization of a New Double Variant Haemoglobin (HbG-Philadelphia/Duarte α(2)β(2)).

PubMed

Fais, Antonella; Casu, Mariano; Ruggerone, Paolo; Ceccarelli, Matteo; Porcu, Simona; Era, Benedetta; Anedda, Roberto; Sollaino, Maria Carla; Galanello, Renzo; Corda, Marcella

2011-01-01

WE REPORT THE FIRST CASE OF COSEGREGATION OF TWO HAEMOGLOBINS (HBS): HbG-Philadelphia [α68(E17)Asn → Lys] and HbDuarte [β62(E6)Ala → Pro]. The proband is a young patient heterozygous also for β°-thalassaemia. We detected exclusively two haemoglobin variants: HbDuarte and HbG-Philadelphia/Duarte. Functional study of the new double variant HbG-Philadelphia/Duarte exhibited an increase in oxygen affinity, with a slight decrease of cooperativity and Bohr effect. This functional behaviour is attributed to β62Ala → Pro instead of α68Asn → Lys substitution. Indeed, HbG-Philadelphia isolated in our laboratory from blood cells donor carrier for this variant is not affected by any functional modification, whereas purified Hb Duarte showed functional properties very similar to the double variant. NMR and MD simulation studies confirmed that the presence of Pro instead of Ala at the β62 position produces displacement of the E helix and modifications of the tertiary structure. The substitution α68(E17)Asn → Lys does not cause significant structural and dynamical modifications of the protein. A possible structure-based rational of substitution effects is suggested.

A novel modification of the Turing test for artificial intelligence and robotics in healthcare.

PubMed

Ashrafian, Hutan; Darzi, Ara; Athanasiou, Thanos

2015-03-01

The increasing demands of delivering higher quality global healthcare has resulted in a corresponding expansion in the development of computer-based and robotic healthcare tools that rely on artificially intelligent technologies. The Turing test was designed to assess artificial intelligence (AI) in computer technology. It remains an important qualitative tool for testing the next generation of medical diagnostics and medical robotics. Development of quantifiable diagnostic accuracy meta-analytical evaluative techniques for the Turing test paradigm. Modification of the Turing test to offer quantifiable diagnostic precision and statistical effect-size robustness in the assessment of AI for computer-based and robotic healthcare technologies. Modification of the Turing test to offer robust diagnostic scores for AI can contribute to enhancing and refining the next generation of digital diagnostic technologies and healthcare robotics. Copyright © 2014 John Wiley & Sons, Ltd.

Scaling up functional traits for ecosystem services with remote sensing: concepts and methods.

PubMed

Abelleira Martínez, Oscar J; Fremier, Alexander K; Günter, Sven; Ramos Bendaña, Zayra; Vierling, Lee; Galbraith, Sara M; Bosque-Pérez, Nilsa A; Ordoñez, Jenny C

2016-07-01

Ecosystem service-based management requires an accurate understanding of how human modification influences ecosystem processes and these relationships are most accurate when based on functional traits. Although trait variation is typically sampled at local scales, remote sensing methods can facilitate scaling up trait variation to regional scales needed for ecosystem service management. We review concepts and methods for scaling up plant and animal functional traits from local to regional spatial scales with the goal of assessing impacts of human modification on ecosystem processes and services. We focus our objectives on considerations and approaches for (1) conducting local plot-level sampling of trait variation and (2) scaling up trait variation to regional spatial scales using remotely sensed data. We show that sampling methods for scaling up traits need to account for the modification of trait variation due to land cover change and species introductions. Sampling intraspecific variation, stratification by land cover type or landscape context, or inference of traits from published sources may be necessary depending on the traits of interest. Passive and active remote sensing are useful for mapping plant phenological, chemical, and structural traits. Combining these methods can significantly improve their capacity for mapping plant trait variation. These methods can also be used to map landscape and vegetation structure in order to infer animal trait variation. Due to high context dependency, relationships between trait variation and remotely sensed data are not directly transferable across regions. We end our review with a brief synthesis of issues to consider and outlook for the development of these approaches. Research that relates typical functional trait metrics, such as the community-weighted mean, with remote sensing data and that relates variation in traits that cannot be remotely sensed to other proxies is needed. Our review narrows the gap between functional trait and remote sensing methods for ecosystem service management.

Economic Effects of Precipitation Enhancement in the Corn Belt.

NASA Astrophysics Data System (ADS)

Gapcia, Philip; Changnon, Stanley; Pinar, Musa

1990-01-01

Policy formulation in weather modification requires an understanding of the economic effects from altered weather. The focus of this study is to provide insight into the beneficiaries of a functioning weather modification technology when applied at various spatial and temporal levels. An econometric model which links the corn/scybean production to U.S. cattle, hog and poultry sectors is used to determine the effects of precipitation enhancement in the U.S. Corn Belt, a humid climatic region. A regional supply formulation permits assessment of weather modification on production, prices, revenues to producers, and savings in consumers expenditures on meat. The results provide insight into the distribution of economic effects, emphasize the importance of careful planning in the use of weather modification technology, and provide useful information on the roles of local, state, and federal governments in the support of weather modification.

Simulating smokers' acceptance of modifications in a cessation program.

PubMed Central

Spoth, R

1992-01-01

Recent research has underscored the importance of assessing barriers to smokers' acceptance of cessation programs. This paper illustrates the use of computer simulations to gauge smokers' response to program modifications which may produce barriers to participation. It also highlights methodological issues encountered in conducting this work. Computer simulations were based on conjoint analysis, a consumer research method which enables measurement of smokers' relative preference for various modifications of cessation programs. Results from two studies are presented in this paper. The primary study used a randomly selected sample of 218 adult smokers who participated in a computer-assisted phone interview. Initially, the study assessed smokers' relative utility rating of 30 features of cessation programs. Utility data were used in computer-simulated comparisons of a low-cost, self-help oriented program under development and five other existing programs. A baseline version of the program under development and two modifications (for example, use of a support group with a higher level of cost) were simulated. Both the baseline version and modifications received a favorable response vis-à-vis comparison programs. Modifications requiring higher program costs were, however, associated with moderately reduced levels of favorable consumer response. The second study used a sample of 70 smokers who responded to an expanded set of smoking cessation program features focusing on program packaging. This secondary study incorporate in-person, computer-assisted interviews at a shopping mall, with smokers viewing an artist's mock-up of various program options on display. A similar pattern of responses to simulated program modifications emerged, with monetary cost apparently playing a key role. The significance of conjoint-based computer simulation as a tool in program development or dissemination, salient methodological issues, and implications for further research are discussed. PMID:1738813

Simulating smokers' acceptance of modifications in a cessation program.

PubMed

Spoth, R

1992-01-01

Recent research has underscored the importance of assessing barriers to smokers' acceptance of cessation programs. This paper illustrates the use of computer simulations to gauge smokers' response to program modifications which may produce barriers to participation. It also highlights methodological issues encountered in conducting this work. Computer simulations were based on conjoint analysis, a consumer research method which enables measurement of smokers' relative preference for various modifications of cessation programs. Results from two studies are presented in this paper. The primary study used a randomly selected sample of 218 adult smokers who participated in a computer-assisted phone interview. Initially, the study assessed smokers' relative utility rating of 30 features of cessation programs. Utility data were used in computer-simulated comparisons of a low-cost, self-help oriented program under development and five other existing programs. A baseline version of the program under development and two modifications (for example, use of a support group with a higher level of cost) were simulated. Both the baseline version and modifications received a favorable response vis-à-vis comparison programs. Modifications requiring higher program costs were, however, associated with moderately reduced levels of favorable consumer response. The second study used a sample of 70 smokers who responded to an expanded set of smoking cessation program features focusing on program packaging. This secondary study incorporate in-person, computer-assisted interviews at a shopping mall, with smokers viewing an artist's mock-up of various program options on display. A similar pattern of responses to simulated program modifications emerged, with monetary cost apparently playing a key role. The significance of conjoint-based computer simulation as a tool in program development or dissemination, salient methodological issues, and implications for further research are discussed.

DNA.

ERIC Educational Resources Information Center

Felsenfeld, Gary

1985-01-01

Structural form, bonding scheme, and chromatin structure of and gene-modification experiments with deoxyribonucleic acid (DNA) are described. Indicates that DNA's double helix is variable and also flexible as it interacts with regulatory and other molecules to transfer hereditary messages. (DH)

Neuroplastic Changes Induced by Cognitive Rehabilitation in Traumatic Brain Injury: A Review.

PubMed

Galetto, Valentina; Sacco, Katiuscia

2017-09-01

Cognitive deficits are among the most disabling consequences of traumatic brain injury (TBI), leading to long-term outcomes and interfering with the individual's recovery. One of the most effective ways to reduce the impact of cognitive disturbance in everyday life is cognitive rehabilitation, which is based on the principles of brain neuroplasticity and restoration. Although there are many studies in the literature focusing on the effectiveness of cognitive interventions in reducing cognitive deficits following TBI, only a few of them focus on neural modifications induced by cognitive treatment. The use of neuroimaging or neurophysiological measures to evaluate brain changes induced by cognitive rehabilitation may have relevant clinical implications, since they could add individualized elements to cognitive assessment. Nevertheless, there are no review studies in the literature investigating neuroplastic changes induced by cognitive training in TBI individuals. Due to lack of data, the goal of this article is to review what is currently known on the cerebral modifications following rehabilitation programs in chronic TBI. Studies investigating both the functional and structural neural modifications induced by cognitive training in TBI subjects were identified from the results of database searches. Forty-five published articles were initially selected. Of these, 34 were excluded because they did not meet the inclusion criteria. Eleven studies were found that focused solely on the functional and neurophysiological changes induced by cognitive rehabilitation. Outcomes showed that cerebral activation may be significantly modified by cognitive rehabilitation, in spite of the severity of the injury.

Chemical modifications of antisense morpholino oligomers enhance their efficacy against Ebola virus infection.

PubMed

Swenson, Dana L; Warfield, Kelly L; Warren, Travis K; Lovejoy, Candace; Hassinger, Jed N; Ruthel, Gordon; Blouch, Robert E; Moulton, Hong M; Weller, Dwight D; Iversen, Patrick L; Bavari, Sina

2009-05-01

Phosphorodiamidate morpholino oligomers (PMOs) are uncharged nucleic acid-like molecules designed to inactivate the expression of specific genes via the antisense-based steric hindrance of mRNA translation. PMOs have been successful at knocking out viral gene expression and replication in the case of acute viral infections in animal models and have been well tolerated in human clinical trials. We propose that antisense PMOs represent a promising class of therapeutic agents that may be useful for combating filoviral infections. We have previously shown that mice treated with a PMO whose sequence is complementary to a region spanning the start codon of VP24 mRNA were protected against lethal Ebola virus challenge. In the present study, we report on the abilities of two additional VP24-specific PMOs to reduce the cell-free translation of a VP24 reporter, to inhibit the in vitro replication of Ebola virus, and to protect mice against lethal challenge when the PMOs are delivered prior to infection. Additionally, structure-activity relationship evaluations were conducted to assess the enhancement of antiviral efficacy associated with PMO chemical modifications that included conjugation with peptides of various lengths and compositions, positioning of conjugated peptides to either the 5' or the 3' terminus, and the conferring of charge modifications by the addition of piperazine moieties. Conjugation with arginine-rich peptides greatly enhanced the antiviral efficacy of VP24-specific PMOs in infected cells and mice during lethal Ebola virus challenge.

Determination of supplier-to-supplier and lot-to-lot variability in glycation of recombinant human serum albumin expressed in Oryza sativa.

PubMed

Frahm, Grant E; Smith, Daryl G S; Kane, Anita; Lorbetskie, Barry; Cyr, Terry D; Girard, Michel; Johnston, Michael J W

2014-01-01

The use of different expression systems to produce the same recombinant human protein can result in expression-dependent chemical modifications (CMs) leading to variability of structure, stability and immunogenicity. Of particular interest are recombinant human proteins expressed in plant-based systems, which have shown particularly high CM variability. In studies presented here, recombinant human serum albumins (rHSA) produced in Oryza sativa (Asian rice) (OsrHSA) from a number of suppliers have been extensively characterized and compared to plasma-derived HSA (pHSA) and rHSA expressed in yeast (Pichia pastoris and Saccharomyces cerevisiae). The heterogeneity of each sample was evaluated using size exclusion chromatography (SEC), reversed-phase high-performance liquid chromatography (RP-HPLC) and capillary electrophoresis (CE). Modifications of the samples were identified by liquid chromatography-mass spectrometry (LC-MS). The secondary and tertiary structure of the albumin samples were assessed with far U/V circular dichroism spectropolarimetry (far U/V CD) and fluorescence spectroscopy, respectively. Far U/V CD and fluorescence analyses were also used to assess thermal stability and drug binding. High molecular weight aggregates in OsrHSA samples were detected with SEC and supplier-to-supplier variability and, more critically, lot-to-lot variability in one manufactures supplied products were identified. LC-MS analysis identified a greater number of hexose-glycated arginine and lysine residues on OsrHSA compared to pHSA or rHSA expressed in yeast. This analysis also showed supplier-to-supplier and lot-to-lot variability in the degree of glycation at specific lysine and arginine residues for OsrHSA. Both the number of glycated residues and the degree of glycation correlated positively with the quantity of non-monomeric species and the chromatographic profiles of the samples. Tertiary structural changes were observed for most OsrHSA samples which correlated well with the degree of arginine/lysine glycation. The extensive glycation of OsrHSA from multiple suppliers may have further implications for the use of OsrHSA as a therapeutic product.

Damage severity assessment in wind turbine blade laboratory model through fuzzy finite element model updating

NASA Astrophysics Data System (ADS)

Turnbull, Heather; Omenzetter, Piotr

2017-04-01

The recent shift towards development of clean, sustainable energy sources has provided a new challenge in terms of structural safety and reliability: with aging, manufacturing defects, harsh environmental and operational conditions, and extreme events such as lightning strikes wind turbines can become damaged resulting in production losses and environmental degradation. To monitor the current structural state of the turbine, structural health monitoring (SHM) techniques would be beneficial. Physics based SHM in the form of calibration of a finite element model (FEMs) by inverse techniques is adopted in this research. Fuzzy finite element model updating (FFEMU) techniques for damage severity assessment of a small-scale wind turbine blade are discussed and implemented. The main advantage is the ability of FFEMU to account in a simple way for uncertainty within the problem of model updating. Uncertainty quantification techniques, such as fuzzy sets, enable a convenient mathematical representation of the various uncertainties. Experimental frequencies obtained from modal analysis on a small-scale wind turbine blade were described by fuzzy numbers to model measurement uncertainty. During this investigation, damage severity estimation was investigated through addition of small masses of varying magnitude to the trailing edge of the structure. This structural modification, intended to be in lieu of damage, enabled non-destructive experimental simulation of structural change. A numerical model was constructed with multiple variable additional masses simulated upon the blades trailing edge and used as updating parameters. Objective functions for updating were constructed and minimized using both particle swarm optimization algorithm and firefly algorithm. FFEMU was able to obtain a prediction of baseline material properties of the blade whilst also successfully predicting, with sufficient accuracy, a larger magnitude of structural alteration and its location.

Progress Toward Overset-Grid Moving Body Capability for USM3D Unstructured Flow Solver

NASA Technical Reports Server (NTRS)

Pandyna, Mohagna J.; Frink, Neal T.; Noack, Ralph W.

2005-01-01

A static and dynamic Chimera overset-grid capability is added to an established NASA tetrahedral unstructured parallel Navier-Stokes flow solver, USM3D. Modifications to the solver primarily consist of a few strategic calls to the Donor interpolation Receptor Transaction library (DiRTlib) to facilitate communication of solution information between various grids. The assembly of multiple overlapping grids into a single-zone composite grid is performed by the Structured, Unstructured and Generalized Grid AssembleR (SUGGAR) code. Several test cases are presented to verify the implementation, assess overset-grid solution accuracy and convergence relative to single-grid solutions, and demonstrate the prescribed relative grid motion capability.