CEC's Policy on Children with Exceptionalities in Charter Schools

ERIC Educational Resources Information Center

Council for Exceptional Children (NJ3), 2011

2011-01-01

The Council for Exceptional Children (CEC) vigorously supports educational reforms within the public schools which promote rigorous learning standards, strong educational outcomes, shared decision making, diverse educational offerings, and the removal of unnecessary administrative requirements. However, such schools must reflect a commitment to…

Emotional suppression and breast cancer: validation research on the Spanish Adaptation of the Courtauld Emotional Control Scale (CECS).

PubMed

Durá, Estrella; Andreu, Yolanda; Galdón, Maria José; Ibáñez, Elena; Pérez, Sandra; Ferrando, Maite; Murgui, Sergio; Martínez, Paula

2010-05-01

Emotional suppression has played an important role in the research on psychosocial factors related to cancer. It has been argued to be an important psychological factor predicting worse psychosocial adjustment in people with cancer and it may mediate health outcomes. The reference instrument in the research on emotional suppression is the Courtauld Emotional Control Scale (CECS). The present study analysed construct validity of a new Spanish adaptation of the CECS in a sample of 175 breast cancer patients. The results confirmed the proposal by Watson and Greer claiming that the CECS is composed of three subscales that measure different dimensions, but not independent, from emotional control. The present Spanish version of the CECS showed high internal consistency in each subseale as well as the total score. According to Derogatis (BSI-18) criteria, emotional suppression predicts clinically significant distress. In short, our results support the reliability, validity and utility of this Spanish adaptation of the CECS in clinical and research settings.

The Mussel Watch California pilot study on contaminants of emerging concern (CECs): synthesis and next steps

USGS Publications Warehouse

Maruya, Keith A.; Dodder, Nathan G.; Weisberg, Stephen B.; Gregorio, Dominic; Bishop, Jonathan S.; Klosterhaus, Susan; Alvarez, David A.; Furlong, Edward T.; Bricker, Suzanne B.; Kimbrough, Kimani L.; Lauenstein, Gunnar G.

2014-01-01

A multiagency pilot study on mussels (Mytilus spp.) collected at 68 stations in California revealed that 98% of targeted contaminants of emerging concern (CECs) were infrequently detectable at concentrations ⩽1 ng/g. Selected chemicals found in commercial and consumer products were more frequently detected at mean concentrations up to 470 ng/g dry wt. The number of CECs detected and their concentrations were greatest for stations categorized as urban or influenced by storm water discharge. Exposure to a broader suite of CECs was also characterized by passive sampling devices (PSDs), with estimated water concentrations of hydrophobic compounds correlated with Mytilus concentrations. The results underscore the need for focused CEC monitoring in coastal ecosystems and suggest that PSDs are complementary to bivalves in assessing water quality. Moreover, the partnership established among participating agencies led to increased spatial coverage, an expanded list of analytes and a more efficient use of available resources.

Asymmetric design for Compound Elliptical Concentrators (CEC) and its geometric flux implications

NASA Astrophysics Data System (ADS)

Jiang, Lun; Winston, Roland

2015-08-01

The asymmetric compound elliptical concentrator (CEC) has been a less discussed subject in the nonimaging optics society. The conventional way of understanding an ideal concentrator is based on maximizing the concentration ratio based on a uniformed acceptance angle. Although such an angle does not exist in the case of CEC, the thermodynamic laws still hold and we can produce concentrators with the maximum concentration ratio allowed by them. Here we restate the problem and use the string method to solve this general problem. Built on the solution, we can discover groups of such ideal concentrators using geometric flux field, or flowline method.

Impact of hydraulic and carbon loading rates of constructed wetlands on contaminants of emerging concern (CECs) removal.

PubMed

Sharif, Fariya; Westerhoff, Paul; Herckes, Pierre

2014-02-01

Constructed wetlands remove trace organic contaminants via synergistic processes involving plant biomass that include hydrolysis, volatilization, sorption, biodegradation, and photolysis. Wetland design conditions, such as hydraulic loading rates (HLRs) and carbon loading rates (CLRs), influence these processes. Contaminant of emerging concern (CEC) removal by wetland plants was investigated at varying HLRs and CLRs. Rate constants and parameters obtained from batch-scale studies were used in a mechanistic model to evaluate the effect of these two loading rates on CEC removal. CLR significantly influenced CEC removal when wetlands were operated at HLR >5 cm/d. High values of CLR increased removal of estradiol and carbamazepine but lowered that of testosterone and atrazine. Without increasing the cumulative HLR, operating two wetlands in series with varying CLRs could be a way to improve CEC removal. Copyright © 2013 Elsevier Ltd. All rights reserved.

The CEC Action Plan for Libraries and IMPACT 2.

ERIC Educational Resources Information Center

de Bruine, R. Frans

1992-01-01

Discusses the role of the Commission of the European Communities (CEC) in the development of the electronic information industry in Europe. Activities aimed at libraries are described; the IMPACT program for developing the market for information services is explained; and problems of multilingualism are addressed. (LRW)

Requirements for CEC POP Machine Protection System

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

Pinayev, I.

2015-02-18

The requirements of CEC POP machine protection system are meant to prevent damage to a vacuum chamber by a missteered electron beam. In this example, beam energy = 22 MeV, Maximal bunch charge = 5 nC, Maximal repetition rate = 78 kHz, Normalized emittance = 5 mm mrad, Minimal β-function = 1 m. From this information the requirements of the protection system can be calculated by factoring the information into equations to find beam densities and temperature excursions.

EPA's Role in the North American Commission for Environmental Cooperation (CEC)

EPA Pesticide Factsheets

EPA takes a leadership role in the Commission for Environmental Cooperation (CEC), an international organization established by the United States, Canada, and Mexico under the North American Agreement on Environmental Cooperation (NAAEC).

News from CEC: High-Leverage Practices in Special Education

ERIC Educational Resources Information Center

TEACHING Exceptional Children, 2017

2017-01-01

In fall 2014, the Council for Exceptional Children's (CEC) Board of Directors approved a proposal from the Professional Standards and Practice Committee (PSPC) to develop a set of high-leverage practices (HLPs) for special education teachers. The CEEDAR Center at the University of Florida, which is funded by the U.S. Department of Education's…

Separation of delta-, gamma- and alpha-tocopherols by CEC.

PubMed

Fanali, Salvatore; Catarcini, Paolo; Quaglia, Maria Giovanna; Camera, Emanuela; Rinaldi, Mariarosa; Picardo, Mauro

2002-08-01

In this study capillary electrochromatography (CEC) was used for the separation of three tocopherols (TOHs), namely delta-, gamma- and alpha-TOH and the antioxidant compound, butylated hydroxytoluene (BHT). The CEC experiments were carried out using an octadecylsilica (ODS) stationary phase packed, in our laboratory, in a fused-silica capillary (100 microm I.D., 365 microm O.D. x 33 cm of total length and 24.6 or 8.4 cm effective length). The mobile phase was composed by a mixture of methanol (MeOH) and acetonitrile (ACN), at different concentrations and 0.01% (w/v) of ammonium acetate. Retention time (t(R)), retention factor (k), resolution (R(s)) of the three TOHs were strongly influenced by the organic solvent composition of the run buffer and by the effective length of the capillary. Optimum experimental conditions were found even employing the short effective length of the capillary achieving the baseline separation of the studied analytes in a relatively short time (less than 5 min). The optimized method was applied to the qualitative analysis of vitamin E (alpha-TOH) present in a human serum extract.

Update on the CeC PoP 704 MHz 5-cell cavity cryomodule design and fabrication

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

Brutus, J. C.; Belomestnykh, S.; Ben-Zvi, I.

2015-05-03

A 5-cell SRF cavity operating at 704 MHz will be used for the Coherent Electron Cooling Proof of Principle (CeC PoP) system under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The CeC PoP experiment will demonstrate the new technique of cooling proton and ion beams that may increase the beam luminosity in certain cases, by as much as tenfold. The 704 MHz cavity will accelerate 2 MeV electrons from a 112 MHz SRF gun up to 22MeV. This paper provides an overview of the design, the project status and schedule of the 704 MHz 5-cellmore » SRF for CeC PoP experiment.« less

Measurement of cation exchange capacity (CEC) on natural zeolite by percolation method

NASA Astrophysics Data System (ADS)

Wiyantoko, Bayu; Rahmah, Nafisa

2017-12-01

The cation exchange capacity (CEC)measurement has been carried out in natural zeolite by percolation method. The natural zeolite samples used for cation exchange capacity measurement were activated beforehand with physical activation and chemical activation. The physically activated zeolite was done by calcination process at 600 °C for 4 hours. The natural zeolite was activated chemically by using sodium hydroxide by refluxing process at 60-80 °C for 3 hours. In summary, cation exchange capacity (CEC) determination was performed by percolation, distillation and titration processes. Based on the measurement that has been done, the exchange rate results from physical activated and chemical activated of natural zeolite were 181.90cmol (+)/kg and 901.49cmol (+)/kg respectively.

Determination of CEC value (Cation Exchange Capacity) of Bentonites from North Aceh and Bener Meriah, Aceh Province, Indonesia using three methods

NASA Astrophysics Data System (ADS)

Rihayat, T.; Salim, S.; Arlina, A.; Fona, Z.; Jalal, R.; Alam, P. N.; Zaimahwati; Sami, M.; Syarif, J.; Juhan, N.

2018-03-01

Research on determination of value CEC (Cation Exchange Capacity) Bentonite North Aceh and Bener Meriah with three methods has been studied. The purpose of this study was to determine the value of CEC bentonite North Aceh and Bener Meriah. The methods used in this research were pH equilibrium, BaCl2/MgSO4 and the adsorption of methylene blue. These three methods used to determine, compare, and calculation of the CEC value and determine the effect of particle size of bentonite on the value of the CEC. Bentonite North Aceh and Bener Meriah sieved with particle sizes of 80, 100, 150, 200, 250 mesh. The results showed that determination of the value of CEC bentonite North Aceh using BaCl2/MgSO4 with a particle size of 250 mesh is the value of the highest, reaching 79.09 meq/100 g.

[The clinical ethics committee (CEC) in the area of conflict between hospital certification, moral pragmatics and scientific approach].

PubMed

Bauer, Axel W

2007-01-01

During the last decade numerous consultative bodies for bioethical and medical ethical issues have been established. In this study we will introduce the clinical ethics committee (CEC), which can be mainly brought into action for three purposes: discussing moral problems in a hospital's everyday work, developing guidelines for the clinic, and giving further education to the hospital's staff. Starting with the denominational hospitals at the end of the 1990s, CECs have been established in the meantime at a large number of German clinics, often in an interrelation with hospital certification. We will describe the process of establishing a CEC at the university hospital in Mannheim (Baden-Württemberg) and examine its formal structure given by the statutes and the standing orders. An important issue of the CEC's activities consists in individual consultation, for instance concerning withholding or withdrawing life-supporting therapy from comatose patients. First and foremost it has to be clarified whether there is really an ethical problem which cannot be solved by those seeking advice or whether the CEC is just asked a rhetorical question in order to attain allies. In this case disappointment will often be the consequence. The quality of an ethical consultation cannot be treated as equivalent to the correspondence with preconceived moral attitudes. The CEC is not a "moral police" but a multi-professional body, in which scientific medical ethics should play an important but under no circumstances a dominating role. Meaningful criteria and measuring methods to study the effectiveness of clinical ethics committees will have to be evolved and tested in practice as soon as possible.

Education for Sustainability--Looking Backward and Looking Forward--IUCN CEC Perspective on the United Nations Decade of ESD

ERIC Educational Resources Information Center

Wheeler, Keith A.; Hesselink, Frits; Goldstein, Wendy

2015-01-01

A network of volunteers, the International Union for Conservation of Nature Commission on Education and Communication (CEC), present some reflections on their contributions towards the field of education for sustainability from 1992 to the present. Many CEC members have been thought leaders to this multidimensional field, and advocates for a more…

Refocusing Mussel Watch on contaminants of emerging concern (CECs): the California pilot study (2009-10)

USGS Publications Warehouse

Maruya, Keith A.; Dodder, Nathan G.; Schaffner, Rebecca A.; Weisberg, Stephen B.; Gregorio, Dominic; Klosterhaus, Susan; Alvarez, David A.; Furlong, Edward T.; Kimbrough, Kimani L.; Lauenstein, Gunnar G.; Christensen, John D.

2014-01-01

To expand the utility of the Mussel Watch Program, local, regional and state agencies in California partnered with NOAA to design a pilot study that targeted contaminants of emerging concern (CECs). Native mussels (Mytilus spp.) from 68 stations, stratified by land use and discharge scenario, were collected in 2009–10 and analyzed for 167 individual pharmaceuticals, industrial and commercial chemicals and current use pesticides. Passive sampling devices (PSDs) and caged Mytilus were co-deployed to expand the list of CECs, and to assess the ability of PSDs to mimic bioaccumulation by Mytilus. A performance-based quality assurance/quality control (QA/QC) approach was developed to ensure a high degree of data quality, consistency and comparability. Data management and analysis were streamlined and standardized using automated software tools. This pioneering study will help shape future monitoring efforts in California’s coastal ecosystems, while serving as a model for monitoring CECs within the region and across the nation.

Educators' Perspectives: Survey on the 2009 CEC Advanced Content Standards

ERIC Educational Resources Information Center

Othman, Lama Bergstrand; Kieran, Laura; Anderson, Christine J.

2015-01-01

Educators who pursue an advanced degree or certification in special education must learn and master the Advanced Content Standards as set forth by the Council for Exceptional Children. These six content standards were validated by the CEC to guide educators through the process of assuming an advanced role in special education teaching or…

US EPA bioeffects monitoring under the Great Lakes Restoration Initiative: Overview of efforts to assess the biological impacts of CECs

EPA Science Inventory

Product Description:Concern exists regarding the potential biological effects of contaminants of emerging concern (CECs) in the Great Lakes. CECs arise from multiple sources, including agriculture, wastewater effluents, and urban nonpoint sources. The Great Lakes Restoration Init...

CEC with new monolithic stationary phase based on a fluorinated monomer, trifluoroethyl methacrylate.

PubMed

Yurtsever, Arda; Saraçoğlu, Berna; Tuncel, Ali

2009-02-01

A new, fluorinated monolithic stationary phase for CEC was first synthesized by a single-stage, thermally initiated copolymerization of a fluorinated monomer, 2,2,2-trifluoroethyl methacrylate (TFEM) and ethylene dimethacrylate (EDMA) in the presence of a porogen mixture. In this preparation, 2-acrylamido-2-methyl-1-propanesulfonic acid was used as the charge-bearing monomer. The porogen mixture was prepared by mixing isoamylalcohol and 1,4-butanediol. A clear increase in the electroosmotic mobility was observed with increasing pH. The electroosmotic mobility decreased with increasing ACN concentration. Poly(TFEM-co-EDMA) monolith prepared under optimized polymerization conditions was successfully used in the separation of alkylbenzenes and phenols by CEC. The best chromatographic separation for alkylbenzenes was performed with lower ACN concentrations (i.e. 60% v/v) with respect to the common acrylic-based CEC monoliths. The theoretical plate numbers up to 220 000 plates/m were achieved in the reversed phase separation of phenols. Poly(TFEM-co-EDMA) monolith also allowed the simultaneous separation of aniline and benzoic acid derivatives by a single run and by using a lower ACN concentration in the mobile phase with respect to the similar electrochromatographic separations. A stable retention behaviour in reversed phase separation of alkylbenzenes was obtained with the poly(TFEM-co-EDMA) monolith.

CEC-atmospheric pressure ionization MS of pesticides using a surfactant-bound monolithic column.

PubMed

Gu, Congying; Shamsi, Shahab A

2010-04-01

A surfactant bound poly (11-acrylaminoundecanoic acid-ethylene dimethacrylate) monolithic column was simply prepared by in situ co-polymerization of 11-acrylaminoundecanoic acid and ethylene dimethacrylate with 1-propanol, 1,4-butanediol and water as porogens in 100 microm id fused-silica capillary in one step. This column was used in CEC-atmospheric pressure photoionization (APPI)-MS system for separation and detection of N-methylcarbamates pesticides. Numerous parameters are optimized for CEC-APPI-MS. After evaluation of the mobile phase composition, sheath liquid composition and the monolithic capillary outlet position, a fractional factorial design was selected as a screening procedure to identify factors of ionization source parameters, such as sheath liquid flow rate, drying gas flow rate, drying gas temperature, nebulizing gas pressure, vaporizer temperature and capillary voltage, which significantly influence APPI-MS sensitivity. A face-centered central composite design was further utilized to optimize the most significant parameters and predict the best sensitivity. Under optimized conditions, S/Ns around 78 were achieved for an injection of 100 ng/mL of each pesticide. Finally, this CEC-APPI-MS method was successfully applied to the analysis of nine N-methylcarbamates in spiked apple juice sample after solid phase extraction with recoveries in the range of 65-109%.

PREFACE: Advances in Cryogenic Engineering: Proceedings of the Cryogenic Engineering Conference (CEC) 2015

NASA Astrophysics Data System (ADS)

Kittel, Peter; Sumption, Michael

2015-12-01

The 2015 joint Cryogenic Engineering and International Cryogenic Materials Conferences were held from June 28 through July 2 at the JW Marriott Starr Pass Resort & Spa in Tucson, Arizona. As at past conferences, the international scope of these meetings was strongly maintained with 26 countries being represented by 561 attendees who gathered to enjoy the joint technical programs, industrial exhibits, special events, and natural beauty of the surrounding Sonoran Desert. The program for the joint conferences included a total of 363 presentations in the plenary, oral, and poster sessions. Four plenary talks gave in-depth discussions of the readiness of bulk superconductors for applications, the role of cryogenics in the development of the hydrogen bomb and vice versa, superconducting turboelectric aircraft propulsion and UPS's uses and plans for LNG fuel. Contributed papers covered a wide range of topics including large-scale and small-scale cryogenics, advances in superconductors and their applications. In total, 234 papers were submitted for publication of which 224 are published in these proceedings. The CEC/ICMC Cryo Industrial Expo displayed the products and services of 38 industrial exhibitors and provided a congenial venue for a reception and refreshments throughout the week as well as the conference poster sessions. Spectacular panoramic views of Saguaro National Park, the Sonoran Desert and the night time lights of Tucson set the stage for a memorable week in the American Southwest. Conference participants enjoyed scenic hikes and bike rides, exploring Old Town Tucson, hot and spicy southwestern cuisine, a nighttime lightning display and a hailstorm. Conference Chairs for 2015 were Peter Kittel, Consultant, for CEC and Michael Sumption from The Ohio State University, Materials Science Department for ICMC. Program Chairs were Jonathan Demko from the LeTourneau University for CEC and Timothy Haugan from AFRL/RQQM for ICMC, assisted by the CEC Program Vice Chair

[BO-CEC National Advisory Committee Meetings and Conference: January 21, 1974; January 13, 1975; July 15, 1975:] Appendix B.

ERIC Educational Resources Information Center

1975

Appendix B to the final report of the Business and Office Career Education Curriculum (BO-CEC) project contains three sections. Sections 1 and 2 briefly present the agenda, the participants, and the reports of the BO-CEC National Advisory Committee Meetings of January 1974 and January 1975. Section 3 concerns the July 1975 dissemination conference…

Experimental design methodologies in the optimization of chiral CE or CEC separations: an overview.

PubMed

Dejaegher, Bieke; Mangelings, Debby; Vander Heyden, Yvan

2013-01-01

In this chapter, an overview of experimental designs to develop chiral capillary electrophoresis (CE) and capillary electrochromatographic (CEC) methods is presented. Method development is generally divided into technique selection, method optimization, and method validation. In the method optimization part, often two phases can be distinguished, i.e., a screening and an optimization phase. In method validation, the method is evaluated on its fit for purpose. A validation item, also applying experimental designs, is robustness testing. In the screening phase and in robustness testing, screening designs are applied. During the optimization phase, response surface designs are used. The different design types and their application steps are discussed in this chapter and illustrated by examples of chiral CE and CEC methods.

New dual asymmetric CEC linear Fresnel concentrator for evacuated tubular receivers

NASA Astrophysics Data System (ADS)

Canavarro, Diogo; Chaves, Julio; Collares-Pereira, Manuel

2017-06-01

Linear Fresnel Reflector concentrators (LFR) are a potential solution for low-cost electricity production. Nevertheless in order to become more competitive with other CSP (Concentrated Solar Power) technologies, in particular with the Parabolic Trough concentrator, their overall solar to electricity efficiencies must increase. A possible path to achieve this goal is to increase the concentration factor, hence increasing the working temperatures for higher thermodynamic efficiency (more energy collection) and decrease the total number of rows of the solar field (less parasitic losses and corresponding cost reduction). This paper presents a dual asymmetric CEC-type (Compound Elliptical Concentrator) LFR (Linear Fresnel Concentrator) for evacuated tubular receivers. The concentrator is designed for a high concentration factor, presenting an asymmetric configuration enabling a very compact solution. The CEC-type secondary mirror is introduced to accommodate very high concentration values with a wide enough acceptance-angle (augmenting optical tolerances) for simple mechanical tracking solutions, achieving a higher CAP (Concentration Acceptance Product) in comparison with conventional LFR solutions. The paper presents an optical and thermal analysis of the concentrator using two different locations, Faro (Portugal) and Hurghada (Egypt).

Evaluation of State Urban Education (CEC) Programs District 19, New York City Board of Education.

ERIC Educational Resources Information Center

Schweitzer, Paul; And Others

The five State Urban Education C.E.C. programs in District 19 include Project Excellence, a recycled clinical program which provides diagnostic, referral, and educational service to elementary and junior school students who demonstrate some difficulty in their scholastic and/or emotional adjustment to school. In Operation Reading Success for Sixth…

Subglacial Lake CECs: Discovery and in situ survey of a privileged research site in West Antarctica

NASA Astrophysics Data System (ADS)

Rivera, Andrés.; Uribe, José; Zamora, Rodrigo; Oberreuter, Jonathan

2015-05-01

We report the discovery and on-the-ground radar mapping of a subglacial lake in Antarctica, that we have named Lake CECs (Centro de Estudios Científicos) in honor of the institute we belong to. It is located in the central part of the West Antarctic Ice Sheet, right underneath the Institute Ice Stream and Minnesota Glacier ice divide, and has not experienced surface elevation changes during the last 10 years. The ratio between the area of the subglacial lake and that of its feeding basin is larger than those for either subglacial lakes Ellsworth or Whillans, and it has a depth comparable to that of Ellsworth and greater than that of Whillans. Its ice thickness is ˜600 m less than that over Ellsworth. The lake is very likely a system with long water residence time. The recent finding of microbial life in Lake Whillans emphasizes the potential of Subglacial Lake CECs for biological exploration.

Development and testing of the questionnaire CEC-61: Knowledge about cervical cancer in Chilean adolescents.

PubMed

Urrutia, María Teresa; Gajardo, Macarena; Padilla, Oslando

2017-05-22

Despite a clear association between human papillomavirus and cervical cancer, knowledge in adolescent populations regarding the disease and methods for its detection and prevention is deficient. The aim of this study was to develop and test a new questionnaire concerning knowledge on cervical cancer. An instrument was developed and validated to measure knowledge in 226 Chilean adolescents between April and June 2011. Content validity, construct validity, and reliability analysis of the instrument were performed. The new, validated instrument, called CEC-61 (Conocimientos en Cancer Cérvicouterino-61 items/Knowledge in Cervical Cancer-61 items), contains nine factors and 61 items. The new questionnaire explained 81% of the variance with a reliability of 0.96. The assessment of knowledge with a valid and reliable instrument is the first step in creating interventions for a population and to encourage appropriate preventive behavior. CEC-61 is highly reliable and has a clear factorial structure to evaluate knowledge in nine domains related to cervical cancer disease, cervical cancer risk, papilloma virus infection, the Papanicolaou test, and the papilloma virus vaccine.

Strengthening Education to Drive Economic Development: A Manual for Replicating "The CEC Experience" in Your Community

ERIC Educational Resources Information Center

Yoder, Karla; Walker James, Donna

2006-01-01

The Central Educational Center (CEC) is a unique educational experience worth replicating in Georgia and nationally. It is a bold experiment--offering required academic courses and state-of-the-art technical and occupational courses to high-school students with the opportunity for dual-enrollment college credit while still in high school. Open to…

Preparation of polyhedral oligomeric silsesquioxane based hybrid monoliths by ring-opening polymerization for capillary LC and CEC.

PubMed

Lin, Hui; Zhang, Zhenbin; Dong, Jing; Liu, Zhongshan; Ou, Junjie; Zou, Hanfa

2013-09-01

A new organic-inorganic hybrid monolith was prepared by the ring-opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxane (POSS) with 1,4-butanediamine (BDA) using 1-propanol, 1,4-butanediol, and PEG 10,000 as a porogenic system. Benefiting from the moderate phase separation process, the resulting poly(POSS-co-BDA) hybrid monolith possessed a uniform microstructure and exhibited excellent performance in chromatographic applications. Neutral, acidic, and basic compounds were successfully separated on the hybrid monolith in capillary LC (cLC), and high column efficiencies were achieved in all of the separations. In addition, as the amino groups could generate a strong EOF, the hybrid monolith was also applied in CEC for the separation of neutral and polar compounds, and a satisfactory performance was obtained. These results demonstrate that the poly(POSS-co-BDA) hybrid monolith is a good separation media in chromatographic separations of various types of compounds by both cLC and CEC. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel use of magnetic biochars for the remediation of soils contaminated by contaminants of emerging concerns (CECs)

NASA Astrophysics Data System (ADS)

Sani, Badruddeen; Mrozik, Wojciech; Werner, David

2016-04-01

The advantage of using magnetic biochar over nonmagnetic biochar in amendments of contaminated soils is in the fact that the former can be easily removed from the soil matrix whenever the need arises, using simple principles of magnetism. In this study, magnetic biochar was produced using a simple co-precipitation technique. The resulting composite has about 33% (w/w) magnetic iron oxides, the presence of which resulted in modification of the biochar's surface characteristics such as BET surface area, porosity and point of zero charge. Modifications in these properties will most likely alter the CEC sorption properties of the biochar, hence the necessity for the proper evaluation of the possible trade off that exist between the need for magnetisation and altered sorption characteristics of the biochar. To achieve this, bottle point sorption experiments in aqueous solutions were conducted using activated and non-activated biochars in magnetic and nonmagnetic forms as sorbents and two pharmaceuticals -ibuprofen and diclofenac- as representative CECs. Sorption isotherms were evaluated and the data was fitted to Langmuir, Freundlich, Redlich-Peterson, Dubinin-Ashtakov and Polanyi-Dubinin-Manes isotherm models. Removal efficiencies and sorption capacities correlated well with the effective mass of pristine biochar used, therefore the sorption characteristics of both magnetic and nonmagnetic biochars are not detrimentally affected by the magnetite impregnation. Biochars in activated form show superior sorption capacities due to amplified surface area and better developed pores. Also, non-activated biochars needed to be used in higher amounts to achieve considerable level of CEC removal, thus they are more easily exhausted. Sorption was observed to decrease with a corresponding increase in solution pH. This suggests that sorption is favoured within the acidic pH range when the surfaces of the sorbents have net positive charge and the sorbates are in their neutral forms.

Nanostructured pillars based on vertically aligned carbon nanotubes as the stationary phase in micro-CEC.

PubMed

Wu, Ren-Guei; Yang, Chung-Shi; Wang, Pen-Cheng; Tseng, Fan-Gang

2009-06-01

We present a micro-CEC chip carrying out a highly efficient separation of dsDNA fragments through vertically aligned multi-wall carbon nanotubes (MWCNTs) in a microchannel. The vertically aligned MWCNTs were grown directly in the microchannel to form straight nanopillar arrays as ordered and directional chromatographic supports. 1-Pyrenedodecanoic acid was employed for the surface modification of the MWCNTs' stationary phase to adsorb analytes by hydrophobic interactions. This device was used for separating dsDNA fragments of three different lengths (254, 360, and 572 bp), and fluorescence detection was employed to verify the electrokinetic transport in the MWCNT array. The micro-CEC separation of the three compounds was achieved in less than 300 s at a field strength of 66 V/cm due to superior laminar flow patterns and a lower flow resistance resulting from the vertically aligned MWCNTs being used as the stationary phase medium. In addition, a fivefold reduction of band broadening was obtained when the analyte was separated by the chromatographic MWCNT array channel instead of the CE channel. From all of the results, we suggest that an in situ grown and directional MWCNT array can potentially be useful for preparing more diversified forms of stationary phases for vertically efficient chip-based electrochromatography.

SEM Anthology

ERIC Educational Resources Information Center

Rodgers, Michelle; Zimar, Heather

2004-01-01

The "SEM Anthology" is a compilation of articles by more than 30 enrollment management professionals from a variety of institutions across the country. This collection, which has appeared in SEM Monthly over the past year, chronicles Strategic Enrollment Management efforts at campuses nationwide. The book illustrates the successes and challenges…

PHOTOMICROPHOTOGRAPHY- GEOLOGY ( SEM)

NASA Image and Video Library

1972-10-13

PHOTOMICROPHOTOGRAPHY -GEOLOGY (SEM) High magnification and resolution views of lunar, meteorite and terrestrial materials using the Scanning Electron MIcroscope (SEM), Bldg. 31 Planetary and Earth Science Laboratory.

Modeling fate and transport of "Contaminants of Emerging Concern" (CECs): is the Soil Water Assessment Tool (SWAT) the appropriate model?

USDA-ARS?s Scientific Manuscript database

Background/Question/Methods As the scientific and regulatory communities realize the significant environmental impacts and ubiquity of “contaminants of emerging concern” (CECs), it is increasingly imperative to develop quantitative assessment tools to evaluate and predict the fate and transport of...

DEVELOPMENT OF A SCALABLE, LOW-COST, ULTRANANOCRYSTALLINE DIAMOND ELECTROCHEMICAL PROCESS FOR THE DESTRUCTION OF CONTAMINANTS OF EMERGING CONCERN (CECS) - PHASE I

EPA Science Inventory

This Small Business Innovative Research (SBIR) project will develop and ready for commercialization a scalable, low-cost process for purification of water containing Contaminants of Emerging Concern (CECs) using anodic oxidation with boron-doped ultrananocrystalline diam...

Think Aloud in Groups: Mediating Poetry for Children with Cecília Meireles, Paulo Freire, and John Dewey

ERIC Educational Resources Information Center

Diniz, Telma Franco

2018-01-01

As suggested by its title, this article reports on a Think Aloud in Group (TAG) practice in which a group of Y5 children thought aloud the poem "The Blue Boy", written in Portuguese by Cecília Meireles and translated into English by Sarah Rebecca Kersley. As a dialogical and collaborative literacy practice, TAG aims to transform the…

Determination of suxamethonium in a pharmaceutical formulation by capillary electrophoresis with contactless conductivity detection (CE-C(4)D).

PubMed

Nussbaumer, Susanne; Fleury-Souverain, Sandrine; Rudaz, Serge; Bonnabry, Pascal; Veuthey, Jean-Luc

2009-02-20

A simple method based on capillary electrophoresis with a capacitively coupled contactless conductivity detector (CE-C(4)D) was developed for the determination of suxamethonium (SUX) in a pharmaceutical formulation. A hydro-organic mixture, consisting of 100mM Tris-acetate buffer at pH 4.2 and acetonitrile (90:10, v/v), was selected as background electrolyte (BGE). The applied voltage was 30kV, and the sample injection was performed in the hydrodynamic mode. All analyses were carried out in a fused silica capillary with an internal diameter of 50 microm and a total length of 64.5cm. Under these conditions, a complete separation between SUX, sodium ions and the main degradation products (choline) was achieved in less than 4min. The presence of acetonitrile in the BGE allowed a reduction of SUX adsorption on the capillary wall. The CE-C(4)D method was validated, and trueness values between 98.8% and 101.1% were obtained with repeatability and intermediate precision values of 0.7-1.3% and 1.2-1.6%, respectively. Therefore, this method was found appropriate for controlling pharmaceutical formulations containing suxamethonium and degradation products.

A Multi-Agency Effort for Assessing the Occurrence and Biological Impacts of CECs in Support of the Great Lakes Restoration Initiative

EPA Science Inventory

In recent years, there has been a substantial increase in the detection of a variety of contaminants for which little is known regarding their potential impact(s) on Great Lakes ecosystems. These contaminants of emerging concern, or CECs, include an assortment of industrial (e.g....

Modified UMS, Modified SemRep and SemMedDB-UTH | Informatics Technology for Cancer Research (ITCR)

Cancer.gov

Modified UMLS, modified SemRep and SemMedDB-UTH – these are resources (UMLS, SemMedDB-UT) and tools (SemRep) created and maintained by National Library of Medicine that we have modified for personalized cancer therapy and returned to the NLM.

SEM-based overlay measurement between via patterns and buried M1 patterns using high-voltage SEM

NASA Astrophysics Data System (ADS)

Hasumi, Kazuhisa; Inoue, Osamu; Okagawa, Yutaka; Shao, Chuanyu; Leray, Philippe; Halder, Sandip; Lorusso, Gian; Jehoul, Christiane

2017-03-01

The miniaturization of semiconductors continues, importance of overlay measurement is increasing. We measured overlay with analysis SEM called Miracle Eye which can output ultrahigh acceleration voltage in 1998. Meanwhile, since 2006, we have been working on SEM based overlay measurement and developed overlay measurement function of the same layer using CD-SEM. Then, we evaluated overlay of the same layer pattern after etching. This time, in order to measure overlay after lithography, we evaluated the see-through overlay using high voltage SEM CV5000 released in October 2016. In collaboration between imec and Hitachi High-Technologies, we evaluated repeatability, TIS of SEM-OVL as well as correlation between SEM-OVL and Opt-OVL in the M1@ADI and V0@ADI process. Repeatability and TIS results are reasonable and SEM-OVL has good correlation with Opt-OVL. By overlay measurement using CV 5000, we got the following conclusions. (1)SEM_OVL results of both M1 and V0 at ADI show good correlation to OPT_OVL. (2)High voltage SEM can prove the measurement capability of a small pattern(Less than 1 2um) like device that can be placed in-die area. (3)"In-die SEM based overlay" shows possibility for high order control of scanner

Commissioning of the 112 MHz SRF Gun and 500 MHz bunching cavities for the CeC PoP Linac

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

Belomestnykh, S.; Ben-Zvi, I.; Brutus, J. C.

The Coherent electron Cooling Proof-of-Principle (CeC PoP) experiment at BNL includes a short electron linac. During Phase 1, a 112 MHz superconducting RF photo-emission gun and two 500 MHz normal conducting bunching cavities were installed and are under commissioning. The paper describes the Phase1 linac layout and presents commissioning results for the cavities and associated RF, cryogenic and other sub-systems

SEMS vs cSEMS in duodenal and small bowel obstruction: High risk of migration in the covered stent group

PubMed Central

Waidmann, Oliver; Trojan, Jörg; Friedrich-Rust, Mireen; Sarrazin, Christoph; Bechstein, Wolf Otto; Ulrich, Frank; Zeuzem, Stefan; Albert, Jörg Gerhard

2013-01-01

AIM: To compare clinical success and complications of uncovered self-expanding metal stents (SEMS) vs covered SEMS (cSEMS) in obstruction of the small bowel. METHODS: Technical success, complications and outcome of endoscopic SEMS or cSEMS placement in tumor related obstruction of the duodenum or jejunum were retrospectively assessed. The primary end points were rates of stent migration and overgrowth. Secondary end points were the effect of concomitant biliary drainage on migration rate and overall survival. The data was analyzed according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. RESULTS: Thirty-two SEMS were implanted in 20 patients. In all patients, endoscopic stent implantation was successful. Stent migration was observed in 9 of 16 cSEMS (56%) in comparison to 0/16 SEMS (0%) implantations (P = 0.002). Stent overgrowth did not significantly differ between the two stent types (SEMS: 3/16, 19%; cSEMS: 2/16, 13%). One cSEMS dislodged and had to be recovered from the jejunum by way of laparotomy. Time until migration between SEMS and cSEMS in patients with and without concomitant biliary stents did not significantly differ (HR = 1.530, 95%CI 0.731-6.306; P = 0.556). The mean follow-up was 57 ± 71 d (range: 1-275 d). CONCLUSION: SEMS and cSEMS placement is safe in small bowel tumor obstruction. However, cSEMS is accompanied with a high rate of migration in comparison to uncovered SEMS. PMID:24115817

Enantiomers Recognition of Propranolol Based on Organic-Inorganic Hybrid Open-Tubular MIPs-CEC Column Using 3-(Trimethoxysilyl)Propyl Methacrylate as a Cross-Linking Monomer.

PubMed

Chen, Guo-Ning; Li, Ning; Luo, Tian; Dong, Yu-Ming

2017-04-01

In this study, 3-(trimethoxysilyl)propyl methacrylate (γ-MPS), a bifunctional group compound, was used as a single cross-linking agent to prepare molecular imprinted inorganic-organic hybrid polymers by in situ polymerization for open-tubular capillary electro chromatography (CEC) column. The optimal preparation conditions were: the ratio between template molecule and functional monomer was 1:4; the volume proportion of porogen toluene and methanol was 1:1 and the volume of cross-linking agent γ-MPS was 69 μL. The optimal separation conditions were separation voltage of 15 kV; detection wavelength at 215 nm and background electrolyte composed of 70% acetonitrile/20 mmol/L boric acid salt (pH 6.9). Under the optimized conditions, the propranolol enantiomers can be separated well by CEC. The method is simple and fast, it can be a potentially useful approach for propranolol enantiomers separation. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

EPA Region 2 SEMS_CERCLIS Sites All [R2] and SEMS_CERCLIS Sites NPL [R2] GIS Layers

EPA Pesticide Factsheets

The Region 2 SEMS_CERCLIS Sites All [R2] GIS layer contains unique Superfund Enterprise Management System (SEMS) site records. These records have the following NPL_STATUS designations: CURRENTLY ON FINAL NPL, DELETED FROM FINAL NPL, NOT ON NPL, PROPOSED FOR NPL, REMOVED FROM PROPOSED NPL, and SITE IS PART OF NPL SITE. The Region 2 SEMS_CERCLIS NPL Sites [R2] GIS layer only has SEMS records with the following NPL_STATUS designations: 'CURRENTLY ON FINAL NPL', 'DELETED FROM FINAL NPL', 'PROPOSED FOR NPL'.The Superfund Enterprise Management System (SEMS) is EPA's official record for tracking hazardous waste sites, potentially hazardous waste sites, and remedial activities performed in support of the Superfund Program across the nation. This includes sites that are on the National Priorities List (NPL) or are being considered for the NPL. SEMS represents a joint development and ongoing collaboration between Superfund's Remedial, Removal, Federal Facilities, Enforcement, and Emergency Response programs. It provides its wide audience base with a means of ongoing analysis of Superfund Program activities and informational needs at the site, regional management, and national management levels. The customers of SEMS or SEMS data are five EPA Headquarters offices and regional staff, citizens, the regulated community, other Federal agencies, States, Tribes, local agencies, and industry. SEMS stakeholders are States, Congress, other Federal agencies, industry groups, and cit

FIB/SEM and SEM/EDS microstructural analysis of metal-ceramic and zirconia-ceramic interfaces.

PubMed

Massimi, F; Merlati, G; Sebastiani, M; Battaini, P; Menghini, P; Bemporad, E

2012-01-10

Recently introduced FIB/SEM analysis in microscopy seems to provide a high-resolution characterization of the samples by 3D (FIB) cross-sectioning and (SEM) high resolution imaging. The aim of this study was to apply the FIB/SEM and SEM/EDS analysis to the interfaces of a metal-ceramic vs. two zirconia-ceramic systems. Plate samples of three different prosthetic systems were prepared in the dental lab following the manufacturers' instructions, where metal-ceramic was the result of a ceramic veneering (porcelain-fused-to-metal) and the two zirconia-ceramic systems were produced by the dedicated CAD-CAM procedures of the zirconia cores (both with final sintering) and then veneered by layered or heat pressed ceramics. In a FIB/SEM equipment (also called DualBeam), a thin layer of platinum (1 μm) was deposited on samples surface crossing the interfaces, in order to protect them during milling. Then, increasingly deeper trenches were milled by a focused ion beam, first using a relatively higher and later using a lower ion current (from 9 nA to 0.28 nA, 30KV). Finally, FEG-SEM (5KV) micrographs (1000-50,000X) were acquired. In a SEM the analysis of the morphology and internal microstructure was performed by 13KV secondary and backscattered electrons signals (in all the samples). The compositional maps were then performed by EDS probe only in the metal-ceramic system (20kV). Despite the presence of many voids in all the ceramic layers, it was possible to identify: (1) the grain structures of the metallic and zirconia substrates, (2) the thin oxide layer at the metal-ceramic interface and its interactions with the first ceramic layer (wash technique), (3) the roughness of the two different zirconia cores and their interactions with the ceramic interface, where the presence of zirconia grains in the ceramic layer was reported in two system possibly due to sandblasting before ceramic firing.

Comparing the detection of iron-based pottery pigment on a carbon-coated sherd by SEM-EDS and by Micro-XRF-SEM.

PubMed

Pendleton, Michael W; Washburn, Dorothy K; Ellis, E Ann; Pendleton, Bonnie B

2014-03-01

The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis.

Comparing the Detection of Iron-Based Pottery Pigment on a Carbon-Coated Sherd by SEM-EDS and by Micro-XRF-SEM

PubMed Central

Pendleton, Michael W.; Washburn, Dorothy K.; Ellis, E. Ann; Pendleton, Bonnie B.

2014-01-01

The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis. PMID:24600333

FIB-SEM tomography in biology.

PubMed

Kizilyaprak, Caroline; Bittermann, Anne Greet; Daraspe, Jean; Humbel, Bruno M

2014-01-01

Three-dimensional information is much easier to understand than a set of two-dimensional images. Therefore a layman is thrilled by the pseudo-3D image taken in a scanning electron microscope (SEM) while, when seeing a transmission electron micrograph, his imagination is challenged. First approaches to gain insight in the third dimension were to make serial microtome sections of a region of interest (ROI) and then building a model of the object. Serial microtome sectioning is a tedious and skill-demanding work and therefore seldom done. In the last two decades with the increase of computer power, sophisticated display options, and the development of new instruments, an SEM with a built-in microtome as well as a focused ion beam scanning electron microscope (FIB-SEM), serial sectioning, and 3D analysis has become far easier and faster.Due to the relief like topology of the microtome trimmed block face of resin-embedded tissue, the ROI can be searched in the secondary electron mode, and at the selected spot, the ROI is prepared with the ion beam for 3D analysis. For FIB-SEM tomography, a thin slice is removed with the ion beam and the newly exposed face is imaged with the electron beam, usually by recording the backscattered electrons. The process, also called "slice and view," is repeated until the desired volume is imaged.As FIB-SEM allows 3D imaging of biological fine structure at high resolution of only small volumes, it is crucial to perform slice and view at carefully selected spots. Finding the region of interest is therefore a prerequisite for meaningful imaging. Thin layer plastification of biofilms offers direct access to the original sample surface and allows the selection of an ROI for site-specific FIB-SEM tomography just by its pronounced topographic features.

Space Experiment Module (SEM)

NASA Technical Reports Server (NTRS)

Brodell, Charles L.

1999-01-01

The Space Experiment Module (SEM) Program is an education initiative sponsored by the National Aeronautics and Space Administration (NASA) Shuttle Small Payloads Project. The program provides nationwide educational access to space for Kindergarten through University level students. The SEM program focuses on the science of zero-gravity and microgravity. Within the program, NASA provides small containers or "modules" for students to fly experiments on the Space Shuttle. The experiments are created, designed, built, and implemented by students with teacher and/or mentor guidance. Student experiment modules are flown in a "carrier" which resides in the cargo bay of the Space Shuttle. The carrier supplies power to, and the means to control and collect data from each experiment.

Sexual Arousal and Sexually Explicit Media (SEM): Comparing Patterns of Sexual Arousal to SEM and Sexual Self-Evaluations and Satisfaction Across Gender and Sexual Orientation.

PubMed

Hald, Gert Martin; Stulhofer, Aleksandar; Lange, Theis

2018-03-01

Investigations of patterns of sexual arousal to certain groups of sexually explicit media (SEM) in the general population in non-laboratory settings are rare. Such knowledge could be important to understand more about the relative specificity of sexual arousal in different SEM users. (i) To investigate whether sexual arousal to non-mainstream vs mainstream SEM contents could be categorized across gender and sexual orientation, (ii) to compare levels of SEM-induced sexual arousal, sexual satisfaction, and self-evaluated sexual interests and fantasies between non-mainstream and mainstream SEM groups, and (iii) to explore the validity and predictive accuracy of the Non-Mainstream Pornography Arousal Scale (NPAS). Online cross-sectional survey of 2,035 regular SEM users in Croatia. Patterns of sexual arousal to 27 different SEM themes, sexual satisfaction, and self-evaluations of sexual interests and sexual fantasies. Groups characterized by sexual arousal to non-mainstream SEM could be identified across gender and sexual orientation. These non-mainstream SEM groups reported more SEM use and higher average levels of sexual arousal across the 27 SEM themes assessed compared with mainstream SEM groups. Only few differences were found between non-mainstream and mainstream SEM groups in self-evaluative judgements of sexual interests, sexual fantasies, and sexual satisfaction. The internal validity and predictive accuracy of the NPAS was good across most user groups investigated. The findings suggest that in classified non-mainstream SEM groups, patterns of sexual arousal might be less fixated and category specific than previously assumed. Further, these groups are not more judgmental of their SEM-related sexual arousal patterns than groups characterized by patterns of sexual arousal to more mainstream SEM content. Moreover, accurate identification of non-mainstream SEM group membership is generally possible across gender and sexual orientation using the NPAS. Hald GM

Framework for SEM contour analysis

NASA Astrophysics Data System (ADS)

Schneider, L.; Farys, V.; Serret, E.; Fenouillet-Beranger, C.

2017-03-01

SEM images provide valuable information about patterning capability. Geometrical properties such as Critical Dimension (CD) can be extracted from them and are used to calibrate OPC models, thus making OPC more robust and reliable. However, there is currently a shortage of appropriate metrology tools to inspect complex two-dimensional patterns in the same way as one would work with simple one-dimensional patterns. In this article we present a full framework for the analysis of SEM images. It has been proven to be fast, reliable and robust for every type of structure, and particularly for two-dimensional structures. To achieve this result, several innovative solutions have been developed and will be presented in the following pages. Firstly, we will present a new noise filter which is used to reduce noise on SEM images, followed by an efficient topography identifier, and finally we will describe the use of a topological skeleton as a measurement tool that can extend CD measurements on all kinds of patterns.

Multi-signal FIB/SEM tomography

NASA Astrophysics Data System (ADS)

Giannuzzi, Lucille A.

2012-06-01

Focused ion beam (FIB) milling coupled with scanning electron microscopy (SEM) on the same platform enables 3D microstructural analysis of structures using FIB for serial sectioning and SEM for imaging. Since FIB milling is a destructive technique, the acquisition of multiple signals from each slice is desirable. The feasibility of collecting both an inlens backscattered electron (BSE) signal and an inlens secondary electron (SE) simultaneously from a single scan of the electron beam from each FIB slice is demonstrated. The simultaneous acquisition of two different SE signals from two different detectors (inlens vs. Everhart-Thornley (ET) detector) is also possible. Obtaining multiple signals from each FIB slice with one scan increases the acquisition throughput. In addition, optimization of microstructural and morphological information from the target is achieved using multi-signals. Examples of multi-signal FIB/SEM tomography from a dental implant will be provided where both material contrast from the bone/ceramic coating/Ti substrate phases and porosity in the ceramic coating will be characterized.

Individual tree size inequality enhances aboveground biomass in homegarden agroforestry systems in the dry zone of Sri Lanka.

PubMed

Ali, Arshad; Mattsson, Eskil

2017-01-01

Individual tree size variation, which is generally quantified by variances in tree diameter at breast height (DBH) and height in isolation or conjunction, plays a central role in ecosystem functioning in both controlled and natural environments, including forests. However, none of the studies have been conducted in homegarden agroforestry systems. In this study, aboveground biomass, stand quality, cation exchange capacity (CEC), DBH variation, and species diversity were determined across 45 homegardens in the dry zone of Sri Lanka. We employed structural equation modeling (SEM) to test for the direct and indirect effects of stand quality and CEC, via tree size inequality and species diversity, on aboveground biomass. The SEM accounted for 26, 8, and 1% of the variation in aboveground biomass, species diversity and DBH variation, respectively. DBH variation had the strongest positive direct effect on aboveground biomass (β=0.49), followed by the non-significant direct effect of species diversity (β=0.17), stand quality (β=0.17) and CEC (β=-0.05). There were non-significant direct effects of CEC and stand quality on DBH variation and species diversity. Stand quality and CEC had also non-significant indirect effects, via DBH variation and species diversity, on aboveground biomass. Our study revealed that aboveground biomass substantially increased with individual tree size variation only, which supports the niche complementarity mechanism. However, aboveground biomass was not considerably increased with species diversity, stand quality and soil fertility, which might be attributable to the adaptation of certain productive species to the local site conditions. Stand structure shaped by few productive species or independent of species diversity is a main determinant for the variation in aboveground biomass in the studied homegardens. Maintaining stand structure through management practices could be an effective approach for enhancing aboveground biomass in these dry

Variation in whole DNA methylation in red maple (Acer rubrum) populations from a mining region: association with metal contamination and cation exchange capacity (CEC) in podzolic soils.

PubMed

Kalubi, K N; Mehes-Smith, M; Spiers, G; Omri, A

2017-04-01

Although a number of publications have provided convincing evidence that abiotic stresses such as drought and high salinity are involved in DNA methylation reports on the effects of metal contamination, pH, and cation exchange on DNA modifications are limited. The main objective of the present study is to determine the relationship between metal contamination and Cation exchange capacity (CEC) on whole DNA modifications. Metal analysis confirms that nickel and copper are the main contaminants in sampled sites within the Greater Sudbury Region (Ontario, Canada) and liming has increased soil pH significantly even after 30 years following dolomitic limestone applications. The estimated CEC values varied significantly among sites, ranging between 1.8 and 10.5 cmol(+) kg -1 , with a strong relationship being observed between CEC and pH (r = 0.96**). Cation exchange capacity, significantly lower in highly metal contaminated sites compared to both reference and less contaminated sites, was higher in the higher organic matter limed compared to unlimed sites. There was a significant variation in the level of cytosine methylation among the metal-contaminated sites. Significant and strong negative correlations between [5mdC]/[dG] and bioavailable nickel (r = -0.71**) or copper (r = -0.72**) contents were observed. The analysis of genomic DNA for adenine methylation in this study showed a very low level of [6N-mdA]/dT] in Acer rubrum plants analyzed ranging from 0 to 0.08%. Significant and very strong positive correlation was observed between [6N-mdA]/dT] and soil bioavailable nickel (r = 0.78**) and copper (r = 0.88**) content. This suggests that the increased bioavailable metal levels associated with contamination by nickel and copper particulates are associated with cytosine and adenine methylation.

Advanced metrology by offline SEM data processing

NASA Astrophysics Data System (ADS)

Lakcher, Amine; Schneider, Loïc.; Le-Gratiet, Bertrand; Ducoté, Julien; Farys, Vincent; Besacier, Maxime

2017-06-01

Today's technology nodes contain more and more complex designs bringing increasing challenges to chip manufacturing process steps. It is necessary to have an efficient metrology to assess process variability of these complex patterns and thus extract relevant data to generate process aware design rules and to improve OPC models. Today process variability is mostly addressed through the analysis of in-line monitoring features which are often designed to support robust measurements and as a consequence are not always very representative of critical design rules. CD-SEM is the main CD metrology technique used in chip manufacturing process but it is challenged when it comes to measure metrics like tip to tip, tip to line, areas or necking in high quantity and with robustness. CD-SEM images contain a lot of information that is not always used in metrology. Suppliers have provided tools that allow engineers to extract the SEM contours of their features and to convert them into a GDS. Contours can be seen as the signature of the shape as it contains all the dimensional data. Thus the methodology is to use the CD-SEM to take high quality images then generate SEM contours and create a data base out of them. Contours are used to feed an offline metrology tool that will process them to extract different metrics. It was shown in two previous papers that it is possible to perform complex measurements on hotspots at different process steps (lithography, etch, copper CMP) by using SEM contours with an in-house offline metrology tool. In the current paper, the methodology presented previously will be expanded to improve its robustness and combined with the use of phylogeny to classify the SEM images according to their geometrical proximities.

Sparsity-Based Super Resolution for SEM Images.

PubMed

Tsiper, Shahar; Dicker, Or; Kaizerman, Idan; Zohar, Zeev; Segev, Mordechai; Eldar, Yonina C

2017-09-13

The scanning electron microscope (SEM) is an electron microscope that produces an image of a sample by scanning it with a focused beam of electrons. The electrons interact with the atoms in the sample, which emit secondary electrons that contain information about the surface topography and composition. The sample is scanned by the electron beam point by point, until an image of the surface is formed. Since its invention in 1942, the capabilities of SEMs have become paramount in the discovery and understanding of the nanometer world, and today it is extensively used for both research and in industry. In principle, SEMs can achieve resolution better than one nanometer. However, for many applications, working at subnanometer resolution implies an exceedingly large number of scanning points. For exactly this reason, the SEM diagnostics of microelectronic chips is performed either at high resolution (HR) over a small area or at low resolution (LR) while capturing a larger portion of the chip. Here, we employ sparse coding and dictionary learning to algorithmically enhance low-resolution SEM images of microelectronic chips-up to the level of the HR images acquired by slow SEM scans, while considerably reducing the noise. Our methodology consists of two steps: an offline stage of learning a joint dictionary from a sequence of LR and HR images of the same region in the chip, followed by a fast-online super-resolution step where the resolution of a new LR image is enhanced. We provide several examples with typical chips used in the microelectronics industry, as well as a statistical study on arbitrary images with characteristic structural features. Conceptually, our method works well when the images have similar characteristics, as microelectronics chips do. This work demonstrates that employing sparsity concepts can greatly improve the performance of SEM, thereby considerably increasing the scanning throughput without compromising on analysis quality and resolution.

Difficult removal of fully covered self expandable metal stents (SEMS) for benign biliary strictures: the "SEMS in SEMS" technique.

PubMed

Tringali, Andrea; Blero, Daniel; Boškoski, Ivo; Familiari, Pietro; Perri, Vincenzo; Devière, Jacques; Costamagna, Guido

2014-06-01

Removal of biliary Fully Covered Self Expandable Metal Stents can fail due to stent migration and/or hyperplastic ingrowth/overgrowth. A case series of 5 patients with benign biliary strictures (2 post-cholecystectomy, 2 following liver transplantation and 1 related to chronic pancreatitis) is reported. The biliary stricture was treated by temporary insertion of Fully Covered Self Expandable Metal Stents. Stent removal failed due to proximal stent migration and/or overgrowth. Metal stent removal was attempted a few weeks after the insertion of another Fully Covered Metal Stent into the first one. The inner Fully Covered Self Expandable Metal Stent compressed the hyperplastic tissue, leading to the extraction of both the stents in all cases. Two complications were reported as a result of the attempt to stents removal (mild pancreatitis and self-limited haemobilia). In the present series, the "SEMS in SEMS" technique revealed to be effective when difficulties are encountered during Fully Covered Self Expandable Metal Stents removal. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Scanning Electron Microscopy (SEM) Procedure for HE Powders on a Zeiss Sigma HD VP SEM

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

Zaka, F.

This method describes the characterization of inert and HE materials by the Zeiss Sigma HD VP field emission Scanning Electron Microscope (SEM). The SEM uses an accelerated electron beam to generate high-magnification images of explosives and other materials. It is fitted with five detectors (SE, Inlens, STEM, VPSE, HDBSD) to enable imaging of the sample via different secondary electron signatures, angles, and energies. In addition to imaging through electron detection, the microscope is also fitted with two Oxford Instrument Energy Dispersive Spectrometer (EDS) 80 mm detectors to generate elemental constituent spectra and two-dimensional maps of the material being scanned.

FIB-SEM cathodoluminescence tomography: practical and theoretical considerations.

PubMed

De Winter, D A M; Lebbink, M N; Wiggers De Vries, D F; Post, J A; Drury, M R

2011-09-01

Focused ion beam-scanning electron microscope (FIB-SEM) tomography is a powerful application in obtaining three-dimensional (3D) information. The FIB creates a cross section and subsequently removes thin slices. The SEM takes images using secondary or backscattered electrons, or maps every slice using X-rays and/or electron backscatter diffraction patterns. The objective of this study is to assess the possibilities of combining FIB-SEM tomography with cathodoluminescence (CL) imaging. The intensity of CL emission is related to variations in defect or impurity concentrations. A potential problem with FIB-SEM CL tomography is that ion milling may change the defect state of the material and the CL emission. In addition the conventional tilted sample geometry used in FIB-SEM tomography is not compatible with conventional CL detectors. Here we examine the influence of the FIB on CL emission in natural diamond and the feasibility of FIB-SEM CL tomography. A systematic investigation establishes that the ion beam influences CL emission of diamond, with a dependency on both the ion beam and electron beam acceleration voltage. CL emission in natural diamond is enhanced particularly at low ion beam and electron beam voltages. This enhancement of the CL emission can be partly explained by an increase in surface defects induced by ion milling. CL emission enhancement could be used to improve the CL image quality. To conduct FIB-SEM CL tomography, a recently developed novel specimen geometry is adopted to enable sequential ion milling and CL imaging on an untilted sample. We show that CL imaging can be manually combined with FIB-SEM tomography with a modified protocol for 3D microstructure reconstruction. In principle, automated FIB-SEM CL tomography should be feasible, provided that dedicated CL detectors are developed that allow subsequent milling and CL imaging without manual intervention, as the current CL detector needs to be manually retracted before a slice can be milled

Maria Cecília Puntel de Almeida: builder of bridges between Nursing and Public Health in Brazil.

PubMed

Scochi, Maria José; Mishima, Silvana Martins; Peduzzi, Marina

2015-12-01

Professor Maria Cecília Puntel de Almeida (1944-2009) built a professional and academic career of which the main feature was her attempt to create and strengthen the interface between Nursing and Public Health in Brazil. From the beginning of her career she recognized this connection and understood the complexity of health problems and peoples' needs when seeking care. Her commitment took the form of both scientific output and also her contributions to the various fields in which she worked. As well as her contribution to the concept of the work process of nursing, she contributed to thinking on health practices and multi-professional training in the construction of a differentiated body of knowledge, which she approached from the perspective of the struggle for democracy in health and understanding of this as a right of citizenship.

Simulation of FIB-SEM images for analysis of porous microstructures.

PubMed

Prill, Torben; Schladitz, Katja

2013-01-01

Focused ion beam nanotomography-scanning electron microscopy tomography yields high-quality three-dimensional images of materials microstructures at the nanometer scale combining serial sectioning using a focused ion beam with SEM. However, FIB-SEM tomography of highly porous media leads to shine-through artifacts preventing automatic segmentation of the solid component. We simulate the SEM process in order to generate synthetic FIB-SEM image data for developing and validating segmentation methods. Monte-Carlo techniques yield accurate results, but are too slow for the simulation of FIB-SEM tomography requiring hundreds of SEM images for one dataset alone. Nevertheless, a quasi-analytic description of the specimen and various acceleration techniques, including a track compression algorithm and an acceleration for the simulation of secondary electrons, cut down the computing time by orders of magnitude, allowing for the first time to simulate FIB-SEM tomography. © Wiley Periodicals, Inc.

Nondestructive SEM for surface and subsurface wafer imaging

NASA Technical Reports Server (NTRS)

Propst, Roy H.; Bagnell, C. Robert; Cole, Edward I., Jr.; Davies, Brian G.; Dibianca, Frank A.; Johnson, Darryl G.; Oxford, William V.; Smith, Craig A.

1987-01-01

The scanning electron microscope (SEM) is considered as a tool for both failure analysis as well as device characterization. A survey is made of various operational SEM modes and their applicability to image processing methods on semiconductor devices.

Recent advances in 3D SEM surface reconstruction.

PubMed

Tafti, Ahmad P; Kirkpatrick, Andrew B; Alavi, Zahrasadat; Owen, Heather A; Yu, Zeyun

2015-11-01

The scanning electron microscope (SEM), as one of the most commonly used instruments in biology and material sciences, employs electrons instead of light to determine the surface properties of specimens. However, the SEM micrographs still remain 2D images. To effectively measure and visualize the surface attributes, we need to restore the 3D shape model from the SEM images. 3D surface reconstruction is a longstanding topic in microscopy vision as it offers quantitative and visual information for a variety of applications consisting medicine, pharmacology, chemistry, and mechanics. In this paper, we attempt to explain the expanding body of the work in this area, including a discussion of recent techniques and algorithms. With the present work, we also enhance the reliability, accuracy, and speed of 3D SEM surface reconstruction by designing and developing an optimized multi-view framework. We then consider several real-world experiments as well as synthetic data to examine the qualitative and quantitative attributes of our proposed framework. Furthermore, we present a taxonomy of 3D SEM surface reconstruction approaches and address several challenging issues as part of our future work. Copyright © 2015 Elsevier Ltd. All rights reserved.

CD-SEM real time bias correction using reference metrology based modeling

NASA Astrophysics Data System (ADS)

Ukraintsev, V.; Banke, W.; Zagorodnev, G.; Archie, C.; Rana, N.; Pavlovsky, V.; Smirnov, V.; Briginas, I.; Katnani, A.; Vaid, A.

2018-03-01

Accuracy of patterning impacts yield, IC performance and technology time to market. Accuracy of patterning relies on optical proximity correction (OPC) models built using CD-SEM inputs and intra die critical dimension (CD) control based on CD-SEM. Sub-nanometer measurement uncertainty (MU) of CD-SEM is required for current technologies. Reported design and process related bias variation of CD-SEM is in the range of several nanometers. Reference metrology and numerical modeling are used to correct SEM. Both methods are slow to be used for real time bias correction. We report on real time CD-SEM bias correction using empirical models based on reference metrology (RM) data. Significant amount of currently untapped information (sidewall angle, corner rounding, etc.) is obtainable from SEM waveforms. Using additional RM information provided for specific technology (design rules, materials, processes) CD extraction algorithms can be pre-built and then used in real time for accurate CD extraction from regular CD-SEM images. The art and challenge of SEM modeling is in finding robust correlation between SEM waveform features and bias of CD-SEM as well as in minimizing RM inputs needed to create accurate (within the design and process space) model. The new approach was applied to improve CD-SEM accuracy of 45 nm GATE and 32 nm MET1 OPC 1D models. In both cases MU of the state of the art CD-SEM has been improved by 3x and reduced to a nanometer level. Similar approach can be applied to 2D (end of line, contours, etc.) and 3D (sidewall angle, corner rounding, etc.) cases.

A Data-Driven Approach to SEM Development at a Two-Year College

ERIC Educational Resources Information Center

Pirius, Landon K.

2014-01-01

This article explores implementation of strategic enrollment management (SEM) at a two-year college and why SEM is critical to the long-term viability of an institution. This article also outlines the five initial steps needed to implement SEM, including identifying SEM leadership, building a SEM committee, developing a common understanding of…

Improvement of CD-SEM mark position measurement accuracy

NASA Astrophysics Data System (ADS)

Kasa, Kentaro; Fukuhara, Kazuya

2014-04-01

CD-SEM is now attracting attention as a tool that can accurately measure positional error of device patterns. However, the measurement accuracy can get worse due to pattern asymmetry as in the case of image based overlay (IBO) and diffraction based overlay (DBO). For IBO and DBO, a way of correcting the inaccuracy arising from measurement patterns was suggested. For CD-SEM, although a way of correcting CD bias was proposed, it has not been argued how to correct the inaccuracy arising from pattern asymmetry using CD-SEM. In this study we will propose how to quantify and correct the measurement inaccuracy affected by pattern asymmetry.

A methodology for extending domain coverage in SemRep.

PubMed

Rosemblat, Graciela; Shin, Dongwook; Kilicoglu, Halil; Sneiderman, Charles; Rindflesch, Thomas C

2013-12-01

We describe a domain-independent methodology to extend SemRep coverage beyond the biomedical domain. SemRep, a natural language processing application originally designed for biomedical texts, uses the knowledge sources provided by the Unified Medical Language System (UMLS©). Ontological and terminological extensions to the system are needed in order to support other areas of knowledge. We extended SemRep's application by developing a semantic representation of a previously unsupported domain. This was achieved by adapting well-known ontology engineering phases and integrating them with the UMLS knowledge sources on which SemRep crucially depends. While the process to extend SemRep coverage has been successfully applied in earlier projects, this paper presents in detail the step-wise approach we followed and the mechanisms implemented. A case study in the field of medical informatics illustrates how the ontology engineering phases have been adapted for optimal integration with the UMLS. We provide qualitative and quantitative results, which indicate the validity and usefulness of our methodology. Published by Elsevier Inc.

Scientific disputes that spill over into Research Ethics: interview with Maria Cecília de Souza Minayo.

PubMed

Minayo, Maria Cecília de Souza

2015-09-01

This is an interview with Maria Cecília de Souza Minayo, by university lecturers Iara Coelho Zito Guerriero and Maria Lúcia Magalhães Bosi. It reflects the heat of the current debates surrounding implementation of a specific protocol for evaluation of research in the Human and Social Sciences (HSS), vis-à-vis the current rules set by the National Health Council, which have a clearly biomedical bias. The interview covers the difficulties of introducing appropriate and fair rules for judgment of HSS projects, in the face of a hegemonic understanding of the very concept of science by biologists and medical doctors, who tend not to recognize other approaches unless those approaches adopt their frames of reference. In this case, the National Health Council becomes the arena of this polemic, leading researchers in the human and social sciences to ask themselves whether the health sector has the competency to create rules for other areas of knowledge.

Safety in the SEM laboratory--1981 update

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

Bance, G.N.; Barber, V.C.; Sholdice, J.A.

1981-01-01

The article reviews recent information on hazards as they relate to safety in SEM laboratories. The first section lists the safety equipment that should be available in a SEM laboratory. Flammable and combustible liquids are discussed, and particular warnings are given concerning the fire and explosion risks associated with diethyl ether and diisopropyl ether. The possible hazards associated with electrical equipment, and the risk of X-ray emissions from EM's are briefly outlined. The hazards associated with acute and chronic toxicity of chemicals used in the EM laboratory are discussed. The need to reduce exposure to a growing list of recognizablemore » hazardous chemicals is emphasized. This reduction can be accomplished by more extensive use of functioning fume hoods, and the use of more appropriate and effective protective gloves. Allergies and the hazards of dangerous pathogens in the SEM laboratory are discussed. The explosion and other hazards associated with cryogens, vacuum evaporators, critical point dryers, and compressed gas cylinders are emphasized.« less

SemVisM: semantic visualizer for medical image

NASA Astrophysics Data System (ADS)

Landaeta, Luis; La Cruz, Alexandra; Baranya, Alexander; Vidal, María.-Esther

2015-01-01

SemVisM is a toolbox that combines medical informatics and computer graphics tools for reducing the semantic gap between low-level features and high-level semantic concepts/terms in the images. This paper presents a novel strategy for visualizing medical data annotated semantically, combining rendering techniques, and segmentation algorithms. SemVisM comprises two main components: i) AMORE (A Modest vOlume REgister) to handle input data (RAW, DAT or DICOM) and to initially annotate the images using terms defined on medical ontologies (e.g., MesH, FMA or RadLex), and ii) VOLPROB (VOlume PRObability Builder) for generating the annotated volumetric data containing the classified voxels that belong to a particular tissue. SemVisM is built on top of the semantic visualizer ANISE.1

Studies of Al-Ti Alloys by SEM

NASA Astrophysics Data System (ADS)

Yildiz, K.; Atici, Y.; Keşlİ Oǧlu, K.; Yaşar, E.

2007-04-01

Al-Ti (1, 2 wt. %) alloys were investigated by Scanning Electron Microscopy (SEM). SEM observations and energy-dispersive x-ray analyses (EDX) showed that the phase structure of Al-Ti (1 %) alloy at 165 μm/s is composed of Al matrix and C, Ni, Fe and Si particles and the Al-Ti (1 %) alloys at 16 and 8 μm/s have only the Al matrix and C particles. It was also found that the Al-Ti (2 %) form the Al matrix and intermetallic TiAl.

Three dimensional profile measurement using multi-channel detector MVM-SEM

NASA Astrophysics Data System (ADS)

Yoshikawa, Makoto; Harada, Sumito; Ito, Keisuke; Murakawa, Tsutomu; Shida, Soichi; Matsumoto, Jun; Nakamura, Takayuki

2014-07-01

In next generation lithography (NGL) for the 1x nm node and beyond, the three dimensional (3D) shape measurements such as side wall angle (SWA) and height of feature on photomask become more critical for the process control. Until today, AFM (Atomic Force Microscope), X-SEM (cross-section Scanning Electron Microscope) and TEM (Transmission Electron Microscope) tools are normally used for 3D measurements, however, these techniques require time-consuming preparation and observation. And both X-SEM and TEM are destructive measurement techniques. This paper presents a technology for quick and non-destructive 3D shape analysis using multi-channel detector MVM-SEM (Multi Vision Metrology SEM), and also reports its accuracy and precision.

Application of SEM and EDX in studying biomineralization in plant tissues.

PubMed

He, Honghua; Kirilak, Yaowanuj

2014-01-01

This chapter describes protocols using formalin-acetic acid-alcohol (FAA) to fix plant tissues for studying biomineralization by means of scanning electron microscopy (SEM) and qualitative energy-dispersive X-ray microanalysis (EDX). Specimen preparation protocols for SEM and EDX mainly include fixation, dehydration, critical point drying (CPD), mounting, and coating. Gold-coated specimens are used for SEM imaging, while gold- and carbon-coated specimens are prepared for qualitative X-ray microanalyses separately to obtain complementary information on the elemental compositions of biominerals. During the specimen preparation procedure for SEM, some biominerals may be dislodged or scattered, making it difficult to determine their accurate locations, and light microscopy is used to complement SEM studies. Specimen preparation protocols for light microscopy generally include fixation, dehydration, infiltration and embedding with resin, microtome sectioning, and staining. In addition, microwave processing methods are adopted here to speed up the specimen preparation process for both SEM and light microscopy.

The Antiphagocytic Activity of SeM of Streptococcus equi Requires Capsule.

PubMed

Timoney, John F; Suther, Pranav; Velineni, Sridhar; Artiushin, Sergey C

2014-01-01

Resistance to phagocytosis is a crucial virulence property of Streptococcus equi (Streptococcus equi subsp. equi; Se), the cause of equine strangles. The contribution and interdependence of capsule and SeM to killing in equine blood and neutrophils were investigated in naturally occurring strains of Se. Strains CF32, SF463 were capsule and SeM positive, strains Lex90, Lex93 were capsule negative and SeM positive and strains Se19, Se1-8 were capsule positive and SeM deficient. Phagocytosis and killing of Se19, Se1-8, Lex90 and Lex93 in equine blood and by neutrophils suspended in serum were significantly (P ≤ 0.02) greater compared to CF32 and SF463. The results indicate capsule and SeM are both required for resistance to phagocytosis and killing and that the anti-phagocytic property of SeM is greatly reduced in the absence of capsule.

A Simulation of the Topographic Contrast in the SEM

NASA Astrophysics Data System (ADS)

Kotera, Masatoshi; Fujiwara, Takafumi; Suga, Hiroshi; Wittry, David B.

1990-10-01

A simulation model is presented to analyze the topographic contast in the scanning electron microscope (SEM). This simulation takes into account all major mechanisms from signal generation to signal detection in the SEM. The calculated result shows that the resolution of the secondary electron image is better than that of the backscattered electron image for 1 and 3 keV primary electrons incident on an Al target. An asymmetric intensity profile of a signal at a topographic pattern, usually found in the SEM equipped with the Everhart-Thornley detector, is mainly due to the asymmetric profile of the backscattered electron signal.

In situ mineralization of hydroxyapatite on electrospun chitosan-based nanofibrous scaffolds.

PubMed

Yang, Dongzhi; Jin, Yu; Zhou, Yingshan; Ma, Guiping; Chen, Xiangmei; Lu, Fengmin; Nie, Jun

2008-03-10

A biocomposite of hydroxyapatite (HAp) with electrospun nanofibrous scaffolds was prepared by using chitosan/polyvinyl alcohol (CS/PVA) and N-carboxyethyl chitosan/PVA (CECS/PVA) electrospun membranes as organic matrix, and HAp was formed in supersaturated CaCl2 and KH2PO4 solution. The influences of carboxylic acid groups in CECS/PVA fibrous scaffold and polyanionic additive poly(acrylic acid) (PAA) in the incubation solution on the crystal distribution of the HAp were investigated. Field-emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), wide-angle X-ray diffraction (WAXD), and Fourier transform infrared (FTIR) were used to characterize the morphology and structure of the deposited mineral phase on the scaffolds. It was found that addition of PAA to the mineral solution and use of matrix with carboxylic acid groups promoted mineral growth and distribution of HAp. MTT testing and SEM imaging from mouse fibroblast (L929) cell culture revealed the attachment and growth of mouse fibroblast on the surface of biocomposite scaffold, and that the cell morphology and viability were satisfactory for the composite to be used in bioapplications.

Multiple-Group Analysis Using the sem Package in the R System

ERIC Educational Resources Information Center

Evermann, Joerg

2010-01-01

Multiple-group analysis in covariance-based structural equation modeling (SEM) is an important technique to ensure the invariance of latent construct measurements and the validity of theoretical models across different subpopulations. However, not all SEM software packages provide multiple-group analysis capabilities. The sem package for the R…

The effect of Sinabung volcanic ash and rock phosphate nanoparticle on CEC (cation exchange capacity) base saturation exchange (K, Na, Ca, Mg) and base saturation at Andisol soils Ciater, West Java

NASA Astrophysics Data System (ADS)

Yuniarti, Anni; Arifin, Mahfud; Sofyan, Emma Trinurasi; Natalie, Betty; Sudirja, Rija; Dahliani, Dewi

2018-02-01

Andisol, soil orders which covers an upland area dominantly. The aim of this research is to know the effect between the ameliorant of Sinabung volcanic ashes with the ameliorant of rock phosphatenanoparticle towards CEC and base saturation exchange (K, Na, Ca, Mg) and the base saturation on Ciater's Andisols, West Java. A randomized complete block design (RCBD) factorial with two factors was used in this research. The first factor is the volcanic ash and the second factor is rock phosphate which consists of four levels each amount of 0%, 2.5%, 5%, 7.5% with three replications. The result showed that there was no interaction between volcanic ash and rock phosphate nanoparticle formed in first month and fourth month towards the improvement of CEC and saturation base exchange rate unless magnesium cation exchange increased in fourth month. There was independent effect of volcanic ash formed nanoparticles towards base saturation exchange increased for 5% dose. There was independent effect of rock phosphate formed nanoparticles towards base saturation exchange and increased for 5% dose. The dose combination of volcanic ashes 7.5% with phosphate rock, 5% increased the base saturation in the first month incubation.

[Contextualized editorial practices: Maria Cecília de Souza Minayo and the journal Ciência & Saúde Coletiva].

PubMed

Spinelli, Hugo; Martinovich, Viviana

2016-01-01

This interview forms part of a series of dialogues that Salud Colectiva has been holding with key editors in the field, with the purpose of examining the similar difficulties confronted by Latin American journals and the diverse ways the journals have faced these difficulties as a likely starting point for uncovering contextualized solutions. In this interview, carried out in 2015 in the Instituto de Salud Colectiva of the Universidad Nacional de Lanús, Maria Cecília de Souza Minayo speaks to us about the context in which the journal Ciência & Saúde Coletiva emerged, the political disputes existing within the collective health field, and the relevance of debate as a constitutive process of science itself. Additionally, Minayo analyzes both the importance of funding to the growth of a journal and the problems and difficulties in obtaining funds, which puts into evidence the lack of policy regarding scientific publishing in Brazil.

SEM: A Cultural Change Agent

ERIC Educational Resources Information Center

Barnes, Bradley; Bourke, Brian

2015-01-01

The authors advance the concept that institutional culture is a purposeful framework by which to view SEM's utility, particularly as a cultural change agent. Through the connection of seemingly independent functions of performance and behavior, implications emerge that deepen the understanding of the influence of culture on performance outcomes…

On the Nature of SEM Estimates of ARMA Parameters.

ERIC Educational Resources Information Center

Hamaker, Ellen L.; Dolan, Conor V.; Molenaar, Peter C. M.

2002-01-01

Reexamined the nature of structural equation modeling (SEM) estimates of autoregressive moving average (ARMA) models, replicated the simulation experiments of P. Molenaar, and examined the behavior of the log-likelihood ratio test. Simulation studies indicate that estimates of ARMA parameters observed with SEM software are identical to those…

CECs and IL-8 Have Prognostic and Predictive Utility in Patients with Recurrent Platinum-Sensitive Ovarian Cancer: Biomarker Correlates from the Randomized Phase-2 Trial of Olaparib and Cediranib Compared with Olaparib in Recurrent Platinum-Sensitive Ovarian Cancer.

PubMed

Lee, Jung-Min; Trepel, Jane B; Choyke, Peter; Cao, Liang; Sissung, Tristan; Houston, Nicole; Yu, Minshu; Figg, William D; Turkbey, Ismail Baris; Steinberg, Seth M; Lee, Min-Jung; Ivy, S Percy; Liu, Joyce F; Matulonis, Ursula A; Kohn, Elise C

2015-01-01

Olaparib (O), a polyADPribose polymerase (PARP) inhibitor, and cediranib (C), a VEGF receptor (VEGFR)1-3 inhibitor together had greater activity than O alone in women with recurrent platinum-sensitive ovarian cancer (OvCa). The objective of this study is to identify potential lead biomarker candidates for response to O + C in the setting of a multi-institutional phase II study of O with and without C in recurrent platinum-sensitive OvCa. A self-selected group of patients participated in a prospectively planned exploratory biomarker substudy of the randomized phase II study of O versus O + C. Whole blood for peripheral blood mononuclear cell (PBMC) and plasma isolation was collected prior to and on day 3 of treatment. Quantitation of circulating endothelial cells (CEC), IL-6, IL-8, VEGF, and soluble VEGFR-2 plasma concentrations, and polyADPribose (PAR) incorporation were performed. Single nucleotide polymorphism analysis of XRCC1 280H, R194W, and Q399R was done. Dynamic contrast-enhanced-magnetic resonance imaging (DCE-MRI) was performed at baseline and day 3 of treatment. Parameter changes were compared between the two arms using an exact Wilcoxon rank sum test. Kaplan-Meier and log-rank tests were used to examine survival outcome. Thirteen patients elected to participate in the translational substudy, seven patients on O and six patients on O + C. Patients on O + C had a greater decrease in IL-8 concentration and larger CEC fold increase compared with those on O alone (p = 0.026, p = 0.032). The fold increase in CEC on day 3 was associated with duration of progression-free survival (PFS) (R (2) = 0.77, 95% CI 0.55-0.97, p < 0.001). IL-8 post-pretreatment changes correlate with PFS (p = 0.028). XRCC1 DNA polymorphisms were not related to PFS. All patients had reduction in PAR incorporation, and all except one had reduction in vascular flow on DCE-MRI. Our exploratory correlative studies indicate that CEC and IL-8 changes may be

The C. elegans Spalt-like protein SEM-4 functions through the SoxC transcription factor SEM-2 to promote a proliferative blast cell fate in the postembryonic mesoderm.

PubMed

Shen, Qinfang; Shi, Herong; Tian, Chenxi; Ghai, Vikas; Liu, Jun

2017-09-01

Proper development of a multicellular organism relies on well-coordinated regulation of cell fate specification, cell proliferation and cell differentiation. The C. elegans postembryonic mesoderm provides a useful system for uncovering factors involved in these processes and for further dissecting their regulatory relationships. The single Spalt-like zinc finger containing protein SEM-4/SALL is known to be involved in specifying the proliferative sex myoblast (SM) fate. We have found that SEM-4/SALL is sufficient to promote the SM fate and that it does so in a cell autonomous manner. We further showed that SEM-4/SALL acts through the SoxC transcription factor SEM-2 to promote the SM fate. SEM-2 is known to promote the SM fate by inhibiting the expression of two BWM-specifying transcription factors. In light of recent findings in mammals showing that Sall4, one of the mammalian homologs of SEM-4, contributes to pluripotency regulation by inhibiting differentiation, our work suggests that the function of SEM-4/SALL proteins in regulating pluripotency versus differentiation appears to be evolutionarily conserved. Copyright © 2017 Elsevier Inc. All rights reserved.

Three-Dimensional (3D) Nanometrology Based on Scanning Electron Microscope (SEM) Stereophotogrammetry.

PubMed

Tondare, Vipin N; Villarrubia, John S; Vlada R, András E

2017-10-01

Three-dimensional (3D) reconstruction of a sample surface from scanning electron microscope (SEM) images taken at two perspectives has been known for decades. Nowadays, there exist several commercially available stereophotogrammetry software packages. For testing these software packages, in this study we used Monte Carlo simulated SEM images of virtual samples. A virtual sample is a model in a computer, and its true dimensions are known exactly, which is impossible for real SEM samples due to measurement uncertainty. The simulated SEM images can be used for algorithm testing, development, and validation. We tested two stereophotogrammetry software packages and compared their reconstructed 3D models with the known geometry of the virtual samples used to create the simulated SEM images. Both packages performed relatively well with simulated SEM images of a sample with a rough surface. However, in a sample containing nearly uniform and therefore low-contrast zones, the height reconstruction error was ≈46%. The present stereophotogrammetry software packages need further improvement before they can be used reliably with SEM images with uniform zones.

Tillandsia stricta Sol (Bromeliaceae) leaves as monitors of airborne particulate matter-A comparative SEM methods evaluation: Unveiling an accurate and odd HP-SEM method.

PubMed

de Oliveira, Martha Lima; de Melo, Edésio José Tenório; Miguens, Flávio Costa

2016-09-01

Airborne particulate matter (PM) has been included among the most important air pollutants by governmental environment agencies and academy researchers. The use of terrestrial plants for monitoring PM has been widely accepted, particularly when it is coupled with SEM/EDS. Herein, Tillandsia stricta leaves were used as monitors of PM, focusing on a comparative evaluation of Environmental SEM (ESEM) and High-Pressure SEM (HPSEM). In addition, specimens air-dried at formaldehyde atmosphere (AD/FA) were introduced as an SEM procedure. Hydrated specimen observation by ESEM was the best way to get information from T. stricta leaves. If any artifacts were introduced by AD/FA, they were indiscernible from those caused by CPD. Leaf anatomy was always well preserved. PM density was determined on adaxial and abaxial leaf epidermis for each of the SEM proceedings. When compared with ESEM, particle extraction varied from 0 to 20% in air-dried leaves while 23-78% of particles deposited on leaves surfaces were extracted by CPD procedures. ESEM was obviously the best choice over other methods but morphological artifacts increased in function of operation time while HPSEM operation time was without limit. AD/FA avoided the shrinkage observed in the air-dried leaves and particle extraction was low when compared with CPD. Structural and particle density results suggest AD/FA as an important methodological approach to air pollution biomonitoring that can be widely used in all electron microscopy labs. Otherwise, previous PM assessments using terrestrial plants as biomonitors and performed by conventional SEM could have underestimated airborne particulate matter concentration. © 2016 Wiley Periodicals, Inc.

3DSEM++: Adaptive and intelligent 3D SEM surface reconstruction.

PubMed

Tafti, Ahmad P; Holz, Jessica D; Baghaie, Ahmadreza; Owen, Heather A; He, Max M; Yu, Zeyun

2016-08-01

Structural analysis of microscopic objects is a longstanding topic in several scientific disciplines, such as biological, mechanical, and materials sciences. The scanning electron microscope (SEM), as a promising imaging equipment has been around for decades to determine the surface properties (e.g., compositions or geometries) of specimens by achieving increased magnification, contrast, and resolution greater than one nanometer. Whereas SEM micrographs still remain two-dimensional (2D), many research and educational questions truly require knowledge and facts about their three-dimensional (3D) structures. 3D surface reconstruction from SEM images leads to remarkable understanding of microscopic surfaces, allowing informative and qualitative visualization of the samples being investigated. In this contribution, we integrate several computational technologies including machine learning, contrario methodology, and epipolar geometry to design and develop a novel and efficient method called 3DSEM++ for multi-view 3D SEM surface reconstruction in an adaptive and intelligent fashion. The experiments which have been performed on real and synthetic data assert the approach is able to reach a significant precision to both SEM extrinsic calibration and its 3D surface modeling. Copyright © 2016 Elsevier Ltd. All rights reserved.

SEM probe of IC radiation sensitivity

NASA Technical Reports Server (NTRS)

Gauthier, M. K.; Stanley, A. G.

1979-01-01

Scanning Electron Microscope (SEM) used to irradiate single integrated circuit (IC) subcomponent to test for radiation sensitivity can localize area of IC less than .03 by .03 mm for determination of exact location of radiation sensitive section.

Using digital colour to increase the realistic appearance of SEM micrographs of bloodstains.

PubMed

Hortolà, Policarp

2010-10-01

Although in the scientific-research literature the micrographs from scanning electron microscopes (SEMs) are usually displayed in greyscale, the potential of colour resources provided by the SEM-coupled image-acquiring systems and, subsidiarily, by image-manipulation free softwares deserves be explored as a tool for colouring SEM micrographs of bloodstains. After acquiring greyscale SEM micrographs of a (dark red to the naked eye) human blood smear on grey chert, they were manually obtained in red tone using both the SEM-coupled image-acquiring system and an image-manipulation free software, as well as they were automatically generated in thermal tone using the SEM-coupled system. Red images obtained by the SEM-coupled system demonstrated lower visual-discrimination capability than the other coloured images, whereas those in red generated by the free software rendered better magnitude of scopic information than the red images generated by the SEM-coupled system. Thermal-tone images, although were further from the real sample colour than the red ones, not only increased their realistic appearance over the greyscale images, but also yielded the best visual-discrimination capability among all the coloured SEM micrographs, and fairly enhanced the relief effect of the SEM micrographs over both the greyscale and the red images. The application of digital colour by means of the facilities provided by an SEM-coupled image-acquiring system or, when required, by an image-manipulation free software provides a user-friendly, quick and inexpensive way of obtaining coloured SEM micrographs of bloodstains, avoiding to do sophisticated, time-consuming colouring procedures. Although this work was focused on bloodstains, well probably other monochromatic or quasi-monochromatic samples are also susceptible of increasing their realistic appearance by colouring them using the simple methods utilized in this study.

30 CFR 250.1901 - What is the goal of my SEMS program?

Code of Federal Regulations, 2011 CFR

2011-07-01

... Section 250.1901 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT... and Environmental Management Systems (SEMS) § 250.1901 What is the goal of my SEMS program? The goal... your SEMS program must be trained to have the skills and knowledge to perform their assigned duties. ...

From patterns to causal understanding: Structural equation modeling (SEM) in soil ecology

USGS Publications Warehouse

Eisenhauer, Nico; Powell, Jeff R; Grace, James B.; Bowker, Matthew A.

2015-01-01

In this perspectives paper we highlight a heretofore underused statistical method in soil ecological research, structural equation modeling (SEM). SEM is commonly used in the general ecological literature to develop causal understanding from observational data, but has been more slowly adopted by soil ecologists. We provide some basic information on the many advantages and possibilities associated with using SEM and provide some examples of how SEM can be used by soil ecologists to shift focus from describing patterns to developing causal understanding and inspiring new types of experimental tests. SEM is a promising tool to aid the growth of soil ecology as a discipline, particularly by supporting research that is increasingly hypothesis-driven and interdisciplinary, thus shining light into the black box of interactions belowground.

Structural Equations and Causal Explanations: Some Challenges for Causal SEM

ERIC Educational Resources Information Center

Markus, Keith A.

2010-01-01

One common application of structural equation modeling (SEM) involves expressing and empirically investigating causal explanations. Nonetheless, several aspects of causal explanation that have an impact on behavioral science methodology remain poorly understood. It remains unclear whether applications of SEM should attempt to provide complete…

Assessing the utility of FIB-SEM images for shale digital rock physics

NASA Astrophysics Data System (ADS)

Kelly, Shaina; El-Sobky, Hesham; Torres-Verdín, Carlos; Balhoff, Matthew T.

2016-09-01

Shales and other unconventional or low permeability (tight) reservoirs house vast quantities of hydrocarbons, often demonstrate considerable water uptake, and are potential repositories for fluid sequestration. The pore-scale topology and fluid transport mechanisms within these nanoporous sedimentary rocks remain to be fully understood. Image-informed pore-scale models are useful tools for studying porous media: a debated question in shale pore-scale petrophysics is whether there is a representative elementary volume (REV) for shale models? Furthermore, if an REV exists, how does it differ among petrophysical properties? We obtain three dimensional (3D) models of the topology of microscale shale volumes from image analysis of focused ion beam-scanning electron microscope (FIB-SEM) image stacks and investigate the utility of these models as a potential REV for shale. The scope of data used in this work includes multiple local groups of neighboring FIB-SEM images of different microscale sizes, corresponding core-scale (milli- and centimeters) laboratory data, and, for comparison, series of two-dimensional (2D) cross sections from broad ion beam SEM images (BIB-SEM), which capture a larger microscale field of view than the FIB-SEM images; this array of data is larger than the majority of investigations with FIB-SEM-derived microscale models of shale. Properties such as porosity, organic matter content, and pore connectivity are extracted from each model. Assessments of permeability with single phase, pressure-driven flow simulations are performed in the connected pore space of the models using the lattice-Boltzmann method. Calculated petrophysical properties are compared to those of neighboring FIB-SEM images and to core-scale measurements of the sample associated with the FIB-SEM sites. Results indicate that FIB-SEM images below ∼5000 μm3 volume (the largest volume analyzed) are not a suitable REV for shale permeability and pore-scale networks; i.e. field of view

Expanding the Conversation about SEM: Advancing SEM Efforts to Improve Student Learning and Persistence--Part I

ERIC Educational Resources Information Center

Yale, Amanda

2010-01-01

It's now nearly ten years since the author started participating in and presenting at national conferences related to strategic enrollment management (SEM). Having entered this profession with nearly 20 years of experience in transitional initiatives related to the first-year experience and academic advisement services, she has perceived an…

SEM based overlay measurement between resist and buried patterns

NASA Astrophysics Data System (ADS)

Inoue, Osamu; Okagawa, Yutaka; Hasumi, Kazuhisa; Shao, Chuanyu; Leray, Philippe; Lorusso, Gian; Baudemprez, Bart

2016-03-01

With the continuous shrink in pattern size and increased density, overlay control has become one of the most critical issues in semiconductor manufacturing. Recently, SEM based overlay of AEI (After Etch Inspection) wafer has been used for reference and optimization of optical overlay (both Image Based Overlay (IBO) and Diffraction Based Overlay (DBO)). Overlay measurement at AEI stage contributes monitor and forecast the yield after formation by etch and calibrate optical measurement tools. however those overlay value seems difficult directly for feedback to a scanner. Therefore, there is a clear need to have SEM based overlay measurements of ADI (After Develop Inspection) wafers in order to serve as reference for optical overlay and make necessary corrections before wafers go to etch. Furthermore, to make the corrections as accurate as possible, actual device like feature dimensions need to be measured post ADI. This device size measurement is very unique feature of CDSEM , which can be measured with smaller area. This is currently possible only with the CD-SEM. This device size measurement is very unique feature of CD-SEM , which can be measured with smaller area. In this study, we assess SEM based overlay measurement of ADI and AEI wafer by using a sample from an N10 process flow. First, we demonstrate SEM based overlay performance at AEI by using dual damascene process for Via 0 (V0) and metal 1 (M1) layer. We also discuss the overlay measurements between litho-etch-litho stages of a triple patterned M1 layer and double pattern V0. Second, to illustrate the complexities in image acquisition and measurement we will measure overlay between M1B resist and buried M1A-Hard mask trench. Finally, we will show how high accelerating voltage can detect buried pattern information by BSE (Back Scattering Electron). In this paper we discuss the merits of this method versus standard optical metrology based corrections.

Human cardiac telocytes: 3D imaging by FIB-SEM tomography

PubMed Central

Cretoiu, D; Hummel, E; Zimmermann, H; Gherghiceanu, M; Popescu, L M

2014-01-01

Telocyte (TC) is a newly identified type of cell in the cardiac interstitium (www.telocytes.com). TCs are described by classical transmission electron microscopy as cells with very thin and long telopodes (Tps; cellular prolongations) having podoms (dilations) and podomers (very thin segments). TCs’ three-dimensional (3D) morphology is still unknown. Cardiac TCs seem to be particularly involved in long and short distance intercellular signalling and, therefore, their 3D architecture is important for understanding their spatial connections. Using focused ion beam scanning electron microscopy (FIB-SEM) we show, for the first time, the whole ultrastructural anatomy of cardiac TCs. 3D reconstruction of cardiac TCs by FIB-SEM tomography confirms that they have long, narrow but flattened (ribbon-like) telopodes, with humps generated by the podoms. FIB-SEM tomography also confirms the network made by TCs in the cardiac interstitium through adherens junctions. This study provides the first FIB-SEM tomography of a human cell type. PMID:25327290

Two novel approaches to study arthropod anatomy by using dualbeam FIB/SEM.

PubMed

Di Giulio, Andrea; Muzzi, Maurizio

2018-03-01

Transmission Electron Microscopy (TEM) has always been the conventional method to study arthropod ultrastructure, while the use of Scanning Electron Microscopy (SEM) was mainly devoted to the examination of the external cuticular structures by secondary electrons. The new generation field emission SEMs are capable to generate images at sub-cellular level, comparable to TEM images employing backscattered electrons. The potential of this kind of acquisition becomes very powerful in the dual beam FIB/SEM where the SEM column is combined with a Focused Ion Beam (FIB) column. FIB uses ions as a nano-scalpel to slice samples fixed and embedded in resin, replacing traditional ultramicrotomy. We here present two novel methods, which optimize the use of FIB/SEM for studying arthropod anatomy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Expanding the Conversation about SEM: Advancing SEM Efforts to Improve Student Learning and Persistence--Part II

ERIC Educational Resources Information Center

Yale, Amanda

2010-01-01

The first article in this two-part series focused on the need for enrollment management conceptual and organizational models to focus more intentionally and purposefully on efforts related to improving student learning, success, and persistence. Time and again, SEM is viewed from a conventional lens comprising marketing, recruitment and …

In Situ Characterization of Boehmite Particles in Water Using Liquid SEM

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

Yao, Juan; Arey, Bruce W.; Yang, Li

In situ imaging and elemental analysis of boehmite (AlOOH) particles in water is realized using the System for Analysis at the Liquid Vacuum Interface (SALVI) and Scanning Electron Microscopy (SEM). This paper describes the method and key steps in integrating the vacuum compatible SAVLI to SEM and obtaining secondary electron (SE) images of particles in liquid in high vacuum. Energy dispersive x-ray spectroscopy (EDX) is used to obtain elemental analysis of particles in liquid. A synthesized AlOOH particle is used as a model in the liquid SEM illustration. Our results demonstrate that particles can be imaged in the SE modemore » with good resolution. The AlOOH EDX spectrum shows significant signal from the Al compared with deionized water and the empty channel control. In situ liquid SEM is a powerful technique to study particles in liquid with many exciting applications. This procedure aims to provide technical details in how to conduct liquid SEM imaging and EDX analysis using SALVI and reduce potential pitfalls using this approach for other researchers.« less

The relationship between cost estimates reliability and BIM adoption: SEM analysis

NASA Astrophysics Data System (ADS)

Ismail, N. A. A.; Idris, N. H.; Ramli, H.; Rooshdi, R. R. Raja Muhammad; Sahamir, S. R.

2018-02-01

This paper presents the usage of Structural Equation Modelling (SEM) approach in analysing the effects of Building Information Modelling (BIM) technology adoption in improving the reliability of cost estimates. Based on the questionnaire survey results, SEM analysis using SPSS-AMOS application examined the relationships between BIM-improved information and cost estimates reliability factors, leading to BIM technology adoption. Six hypotheses were established prior to SEM analysis employing two types of SEM models, namely the Confirmatory Factor Analysis (CFA) model and full structural model. The SEM models were then validated through the assessment on their uni-dimensionality, validity, reliability, and fitness index, in line with the hypotheses tested. The final SEM model fit measures are: P-value=0.000, RMSEA=0.079<0.08, GFI=0.824, CFI=0.962>0.90, TLI=0.956>0.90, NFI=0.935>0.90 and ChiSq/df=2.259; indicating that the overall index values achieved the required level of model fitness. The model supports all the hypotheses evaluated, confirming that all relationship exists amongst the constructs are positive and significant. Ultimately, the analysis verified that most of the respondents foresee better understanding of project input information through BIM visualization, its reliable database and coordinated data, in developing more reliable cost estimates. They also perceive to accelerate their cost estimating task through BIM adoption.

SEM Analysis of Surface Impact on Biofilm Antibiotic Treatment.

PubMed

Gomes, Luciana Calheiros; Mergulhão, Filipe José

2017-01-01

The aim of this work was to use scanning electron microscopy (SEM) to investigate the effect of ampicillin treatment on Escherichia coli biofilms formed on two surface materials with different properties, silicone (SIL) and glass (GLA). Epifluorescence microscopy (EM) was initially used to assess biofilm formation and killing efficiency on both surfaces. This technique showed that higher bacterial colonization was obtained in the hydrophobic SIL than in the hydrophilic GLA. It has also shown that higher biofilm inactivation was attained for GLA after the antibiotic treatment (7-log reduction versus 1-log reduction for SIL). Due to its high resolution and magnification, SEM enabled a more detailed analysis of the antibiotic effect on biofilm cells, complementing the killing efficiency information obtained by EM. SEM micrographs revealed that ampicillin-treated cells have an elongated form when compared to untreated cells. Additionally, it has shown that different materials induced different levels of elongation on cells exposed to antibiotic. Biofilms formed on GLA showed a 37% higher elongation than those formed on SIL. Importantly, cell elongation was related to viability since ampicillin had a higher bactericidal effect on GLA-formed biofilms. These findings raise the possibility of using SEM for understanding the efficacy of antimicrobial treatments by observation of biofilm morphology.

Focused ion beam (FIB)/scanning electron microscopy (SEM) in tissue structural research.

PubMed

Leser, Vladka; Milani, Marziale; Tatti, Francesco; Tkalec, Ziva Pipan; Strus, Jasna; Drobne, Damjana

2010-10-01

The focused ion beam (FIB) and scanning electron microscope (SEM) are commonly used in material sciences for imaging and analysis of materials. Over the last decade, the combined FIB/SEM system has proven to be also applicable in the life sciences. We have examined the potential of the focused ion beam/scanning electron microscope system for the investigation of biological tissues of the model organism Porcellio scaber (Crustacea: Isopoda). Tissue from digestive glands was prepared as for conventional SEM or as for transmission electron microscopy (TEM). The samples were transferred into FIB/SEM for FIB milling and an imaging operation. FIB-milled regions were secondary electron imaged, back-scattered electron imaged, or energy dispersive X-ray (EDX) analyzed. Our results demonstrated that FIB/SEM enables simultaneous investigation of sample gross morphology, cell surface characteristics, and subsurface structures. The same FIB-exposed regions were analyzed by EDX to provide basic compositional data. When samples were prepared as for TEM, the information obtained with FIB/SEM is comparable, though at limited magnification, to that obtained from TEM. A combination of imaging, micro-manipulation, and compositional analysis appears of particular interest in the investigation of epithelial tissues, which are subjected to various endogenous and exogenous conditions affecting their structure and function. The FIB/SEM is a promising tool for an overall examination of epithelial tissue under normal, stressed, or pathological conditions.

Recent improvement of a FIB-SEM serial-sectioning method for precise 3D image reconstruction - application of the orthogonally-arranged FIB-SEM.

PubMed

Hara, Toru

2014-11-01

IntroductionWe installed the first "orthogonally-arranged" FIB-SEM in 2011. The most characteristic point of this instrument is that the FIB and SEM columns are perpendicularly mounted; this is specially designed to obtain a serial-sectioning dataset more accurately and precisely with higher contrast and higher spatial resolution compare to other current FIB-SEMs [1]. Since the installation in 2011, we have developed the hardware and methodology of the serial-sectioning based on this orthogonal FIB-SEM. In order to develop this technique, we have widely opened this instrument to every researcher of all fields. In the presentation, I would like to introduce some of application results that are obtained by users of this instrument. The characteristic points of the orthogonal systemFigure 1 shows a difference between the standard and the orthogonal FIB-SEM systems: In the standard system, shown in Fig.1(a), optical axes of a FIB and a SEM crosses around 60deg., while in the orthogonal system (Fig.1(b)), they are perpendicular to each other. The standard arrangement (a) is certainly suitable for TEM lamellae preparation etc. because the FIB and the SEM can see the same position simultaneously. However, for a serial-sectioning, it is not to say the best arrangement. One of the reasons is that the sliced plane by the FIB is not perpendicular to the electron beam so that the background contrast is not uniform and observed plane is distorted. On the other hand, in case of the orthogonally-arranged system,(b), these problems are resolved. In addition, spatial resolution can keep high enough even in a low accelerating voltage (e.g. 500V) because a working distance is set very small, 2mm. From these special design, we can obtain the serial-sectioning dataset from rather wide area (∼100um) with high spatial resolution (Max. 2×2×2nm). As this system has many kinds of detectors: SE, ET, Backscatter Electron(Energy-selective), EDS, EBSD, STEM(BF&ADF), with Ar+ ion-gun and a

Building a SEM Analytics Reporting Portfolio

ERIC Educational Resources Information Center

Goff, Jay W.; Williams, Brian G.; Kilgore, Wendy

2016-01-01

Effective strategic enrollment management (SEM) efforts require vast amounts of internal and external data to ensure that meaningful reporting and analysis systems can assist managers in decision making. A wide range of information is integral for leading effective and efficient student recruitment and retention programs. This article is designed…

Human cardiac telocytes: 3D imaging by FIB-SEM tomography.

PubMed

Cretoiu, D; Hummel, E; Zimmermann, H; Gherghiceanu, M; Popescu, L M

2014-11-01

Telocyte (TC) is a newly identified type of cell in the cardiac interstitium (www.telocytes.com). TCs are described by classical transmission electron microscopy as cells with very thin and long telopodes (Tps; cellular prolongations) having podoms (dilations) and podomers (very thin segments). TCs' three-dimensional (3D) morphology is still unknown. Cardiac TCs seem to be particularly involved in long and short distance intercellular signalling and, therefore, their 3D architecture is important for understanding their spatial connections. Using focused ion beam scanning electron microscopy (FIB-SEM) we show, for the first time, the whole ultrastructural anatomy of cardiac TCs. 3D reconstruction of cardiac TCs by FIB-SEM tomography confirms that they have long, narrow but flattened (ribbon-like) telopodes, with humps generated by the podoms. FIB-SEM tomography also confirms the network made by TCs in the cardiac interstitium through adherens junctions. This study provides the first FIB-SEM tomography of a human cell type. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

In Situ Characterization of Boehmite Particles in Water Using Liquid SEM.

PubMed

Yao, Juan; Arey, Bruce W; Yang, Li; Zhang, Fei; Komorek, Rachel; Chun, Jaehun; Yu, Xiao-Ying

2017-09-27

In situ imaging and elemental analysis of boehmite (AlOOH) particles in water is realized using the System for Analysis at the Liquid Vacuum Interface (SALVI) and Scanning Electron Microscopy (SEM). This paper describes the method and key steps in integrating the vacuum compatible SAVLI to SEM and obtaining secondary electron (SE) images of particles in liquid in high vacuum. Energy dispersive x-ray spectroscopy (EDX) is used to obtain elemental analysis of particles in liquid and control samples including deionized (DI) water only and an empty channel as well. Synthesized boehmite (AlOOH) particles suspended in liquid are used as a model in the liquid SEM illustration. The results demonstrate that the particles can be imaged in the SE mode with good resolution (i.e., 400 nm). The AlOOH EDX spectrum shows significant signal from the aluminum (Al) when compared with the DI water and the empty channel control. In situ liquid SEM is a powerful technique to study particles in liquid with many exciting applications. This procedure aims to provide technical know-how in order to conduct liquid SEM imaging and EDX analysis using SALVI and to reduce potential pitfalls when using this approach.

Three dimensional rock microstructures: insights from FIB-SEM tomography

NASA Astrophysics Data System (ADS)

Drury, Martyn; Pennock, Gill; de Winter, Matthijs

2016-04-01

Most studies of rock microstructures investigate two-dimensional sections or thin slices of three dimensional grain structures. With advances of X-ray and electron tomography methods the 3-D microstructure can be(relatively) routinely investigated on scales from a few microns to cm. 3D studies are needed to investigate the connectivity of microstructures and to test the assumptions we use to calculate 3D properties from 2D sections. We have used FIB-SEM tomography to study the topology of melts in synthetic olivine rocks, 3D crystal growth microstructures, pore networks and subgrain structures. The technique uses a focused ion beam to make serial sections with a spacing of tens to hundreds of nanometers. Each section is then imaged or mapped using the electron beam. The 3D geometry of grains and subgrains can be investigated using orientation contrast or EBSD mapping. FIB-SEM tomography of rocks and minerals can be limited by charging of the uncoated surfaces exposed by the ion beam. The newest generation of FIB-SEMs have much improved low voltage imaging capability allowing high resolution charge free imaging. Low kV FIB-SEM tomography is now widely used to study the connectivity of pore networks. In-situ fluids can also be studied using cryo-FIB-SEM on frozen samples, although special freezing techniques are needed to avoid artifacts produced by ice crystallization. FIB-SEM tomography is complementary, in terms of spatial resolution and sampled volume, to TEM tomography and X-ray tomography, and the combination of these methods can cover a wide range of scales. Our studies on melt topology in synthetic olivine rocks with a high melt content show that many grain boundaries are wetted by nanometre scale melt layers that are too thin to resolve by X-ray tomography. A variety of melt layer geometries occur consistent with several mechanisms of melt layer formation. The nature of melt geometries along triple line junctions and quadruple points can be resolved

Comparison of SEM and VPSEM imaging techniques with respect to Streptococcus mutans biofilm topography.

PubMed

Weber, Kathryn; Delben, Juliana; Bromage, Timothy G; Duarte, Simone

2014-01-01

The study compared images of mature Streptococcus mutans biofilms captured at increasing magnification to determine which microscopy method is most acceptable for imaging the biofilm topography and the extracellular polymeric substance (EPS). In vitro S. mutans biofilms were imaged using (1) scanning electron microscopy (SEM), which requires a dehydration process; (2) SEM and ruthenium red (SEM-RR), which has been shown to support the EPS of biofilms during the SEM dehydration; and (3) variable pressure scanning electron microscopy (VPSEM), which does not require the intensive dehydration process of SEM. The dehydration process and high chamber vacuum of both SEM techniques devastated the biofilm EPS, removed supporting structures, and caused cracking on the biofilm surface. The VPSEM offered the most comprehensive representation of the S. mutans biofilm morphology. VPSEM provides similar contrast and focus as the SEM, but the procedure is far less time-consuming, and the use of hazardous chemicals associated with SEM dehydration protocol is avoided with the VPSEM. The inaccurate representations of the biofilm EPS in SEM experimentation is a possible source of inaccurate data and impediments in the study of S. mutans biofilms. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Inter-operator and inter-device agreement and reliability of the SEM Scanner.

PubMed

Clendenin, Marta; Jaradeh, Kindah; Shamirian, Anasheh; Rhodes, Shannon L

2015-02-01

The SEM Scanner is a medical device designed for use by healthcare providers as part of pressure ulcer prevention programs. The objective of this study was to evaluate the inter-rater and inter-device agreement and reliability of the SEM Scanner. Thirty-one (31) volunteers free of pressure ulcers or broken skin at the sternum, sacrum, and heels were assessed with the SEM Scanner. Each of three operators utilized each of three devices to collect readings from four anatomical sites (sternum, sacrum, left and right heels) on each subject for a total of 108 readings per subject collected over approximately 30 min. For each combination of operator-device-anatomical site, three SEM readings were collected. Inter-operator and inter-device agreement and reliability were estimated. Over the course of this study, more than 3000 SEM Scanner readings were collected. Agreement between operators was good with mean differences ranging from -0.01 to 0.11. Inter-operator and inter-device reliability exceeded 0.80 at all anatomical sites assessed. The results of this study demonstrate the high reliability and good agreement of the SEM Scanner across different operators and different devices. Given the limitations of current methods to prevent and detect pressure ulcers, the SEM Scanner shows promise as an objective, reliable tool for assessing the presence or absence of pressure-induced tissue damage such as pressure ulcers. Copyright © 2015 Bruin Biometrics, LLC. Published by Elsevier Ltd.. All rights reserved.

Automated CD-SEM recipe creation technology for mass production using CAD data

NASA Astrophysics Data System (ADS)

Kawahara, Toshikazu; Yoshida, Masamichi; Tanaka, Masashi; Ido, Sanyu; Nakano, Hiroyuki; Adachi, Naokaka; Abe, Yuichi; Nagatomo, Wataru

2011-03-01

Critical Dimension Scanning Electron Microscope (CD-SEM) recipe creation needs sample preparation necessary for matching pattern registration, and recipe creation on CD-SEM using the sample, which hinders the reduction in test production cost and time in semiconductor manufacturing factories. From the perspective of cost reduction and improvement of the test production efficiency, automated CD-SEM recipe creation without the sample preparation and the manual operation has been important in the production lines. For the automated CD-SEM recipe creation, we have introduced RecipeDirector (RD) that enables the recipe creation by using Computer-Aided Design (CAD) data and text data that includes measurement information. We have developed a system that automatically creates the CAD data and the text data necessary for the recipe creation on RD; and, for the elimination of the manual operation, we have enhanced RD so that all measurement information can be specified in the text data. As a result, we have established an automated CD-SEM recipe creation system without the sample preparation and the manual operation. For the introduction of the CD-SEM recipe creation system using RD to the production lines, the accuracy of the pattern matching was an issue. The shape of design templates for the matching created from the CAD data was different from that of SEM images in vision. Thus, a development of robust pattern matching algorithm that considers the shape difference was needed. The addition of image processing of the templates for the matching and shape processing of the CAD patterns in the lower layer has enabled the robust pattern matching. This paper describes the automated CD-SEM recipe creation technology for the production lines without the sample preparation and the manual operation using RD applied in Sony Semiconductor Kyusyu Corporation Kumamoto Technology Center (SCK Corporation Kumamoto TEC).

Correlative SEM SERS for quantitative analysis of dimer nanoparticles.

PubMed

Timmermans, F J; Lenferink, A T M; van Wolferen, H A G M; Otto, C

2016-11-14

A Raman microscope integrated with a scanning electron microscope was used to investigate plasmonic structures by correlative SEM-SERS analysis. The integrated Raman-SEM microscope combines high-resolution electron microscopy information with SERS signal enhancement from selected nanostructures with adsorbed Raman reporter molecules. Correlative analysis is performed for dimers of two gold nanospheres. Dimers were selected on the basis of SEM images from multi aggregate samples. The effect of the orientation of the dimer with respect to the polarization state of the laser light and the effect of the particle gap size on the Raman signal intensity is observed. Additionally, calculations are performed to simulate the electric near field enhancement. These simulations are based on the morphologies observed by electron microscopy. In this way the experiments are compared with the enhancement factor calculated with near field simulations and are subsequently used to quantify the SERS enhancement factor. Large differences between experimentally observed and calculated enhancement factors are regularly detected, a phenomenon caused by nanoscale differences between the real and 'simplified' simulated structures. Quantitative SERS experiments reveal the structure induced enhancement factor, ranging from ∼200 to ∼20 000, averaged over the full nanostructure surface. The results demonstrate correlative Raman-SEM microscopy for the quantitative analysis of plasmonic particles and structures, thus enabling a new analytical method in the field of SERS and plasmonics.

Focused Ion Beam (FIB) combined with SEM (FIB/SEM) and TEM: Advanced tools for nano-analysis in Geosciences

NASA Astrophysics Data System (ADS)

Wirth, R.; Morales, L. G.

2011-12-01

Focused ion beam (FIB) techniques have been successfully applied to the preparation of site-specific electron transparent membranes for transmission electron microscopy (TEM) investigations in Geosciences since several years. For example, systematic TEM studies of nano-inclusions in diamond foils prepared with FIB have improved our knowledge on diamond formation. However, FIB is not exclusively used for sample preparation for TEM application because it has been proved that one and the same TEM foil can also be used for Synchrotron IR, Synchrotron X-Ray fluorescence (XRF), scanning transmission X-Ray microscopy (STXM) and NanoSIMS analysis. In addition, FIB milling turned out to be very useful for sample preparation of Brillouin scattering experiments and has a strong potential for preparation of highly-polished, micrometer-scale samples. However, a real break through in FIB application was achieved combining a Ga-ion source of the FIB with an electron source of a scanning electron microscope (SEM) in one single instrument. The combination of FIB/SEM renders access to the third dimension of the sample possible. A cavity normal to the sample surface is sputtered with Ga-ions and this newly created inner surface is imaged with the electron beam. Alternating slicing and viewing along these cavities allow the acquisition of a sequence of images that allows the observation in 3 dimensions. Recently, this technique has been successfully applied to image the structure of grain or phase boundaries in metamorphic rocks as well as micro- and nanoporosity in shales, but its applicability goes far beyond these few examples. Combining slicing and viewing with X-Ray and electron backscatter diffraction (EBSD) analysis can provide 3D elemental mapping and 3D crystallographic orientation mapping of crystalline materials. Combined FIB/SEM devices also facilitate the preparation of substantially thinner and cleaner TEM foils (approximately 30 nm) because electron beam imaging

GAGG:ce single crystalline films: New perspective scintillators for electron detection in SEM.

PubMed

Bok, Jan; Lalinský, Ondřej; Hanuš, Martin; Onderišinová, Zuzana; Kelar, Jakub; Kučera, Miroslav

2016-04-01

Single crystal scintillators are frequently used for electron detection in scanning electron microscopy (SEM). We report gadolinium aluminum gallium garnet (GAGG:Ce) single crystalline films as a new perspective scintillators for the SEM. For the first time, the epitaxial garnet films were used in a practical application: the GAGG:Ce scintillator was incorporated into a SEM scintillation electron detector and it showed improved image quality. In order to prove the GAGG:Ce quality accurately, the scintillation properties were examined using electron beam excitation and compared with frequently used scintillators in the SEM. The results demonstrate excellent emission efficiency of the GAGG:Ce single crystalline films together with their very fast scintillation decay useful for demanding SEM applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Diversity of seM in Streptococcus equi subsp. equi isolated from strangles outbreaks.

PubMed

Libardoni, Felipe; Vielmo, Andréia; Farias, Luana; Matter, Letícia Beatriz; Pötter, Luciana; Spilki, Fernando Rosado; de Vargas, Agueda Castagna

2013-03-23

Strangles is the main upper respiratory tract disease of horses. There are currently no studies on the changes in alleles of the M protein gene (seM) in Brazilian isolates of Streptococcus equi ssp. equi (S. equi). This study aimed to analyze and differentiate molecularly S. equi isolates from equine clinical specimens from southern Brazil, between 1994 and 2010. seM alleles were analyzed in 47 isolates of S. equi obtained from clinical cases of strangles (15 Thoroughbred horses, 29 Crioulo breed horses and three Brasileiro de Hipismo--BH). seM alleles characterization was performed by comparing variable region sequences of the seM gene. The alleles were also phylogenetically grouped by Neighbor-joining analysis, which demonstrated the geographic distribution of those in properties from southern Brazil. Fifteen alleles of the gene seM were found among the 47 S. equi isolates analyzed. Among these, only one allele (seM-61), which was identified in seven isolates (14.9%), was found in the database PubMLST-seM. Within the new alleles, allele seM-115 was the most prevalent, having been found in 13 isolates (27.7%), followed by allele seM-117 in 10 isolates (21.3%). In the Brazilian horse population studied, there is greater diversity of M protein alleles in S. equi isolates compared to worldwide data deposited in PubMLST-seM. Among the 15 seM alleles identified, only one allele sequence was previously published. The alleles identification is important to control the disease by guiding selection of strains for the manufacture of commercial and autogenous vaccines. Copyright © 2012 Elsevier B.V. All rights reserved.

Automated SEM-EDS GSR Analysis for Turkish Ammunitions

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

Cakir, Ismail; Uner, H. Bulent

2007-04-23

In this work, Automated Scanning Electron Microscopy with Energy Dispersive X-ray Spectrometry (SEM-EDS) was used to characterize 7.65 and 9mm cartridges Turkish ammunition. All samples were analyzed in a SEM Jeol JSM-5600LV equipped BSE detector and a Link ISIS 300 (EDS). A working distance of 20mm, an accelerating voltage of 20 keV and gunshot residue software was used in all analysis. Automated search resulted in a high number of particles analyzed containing gunshot residues (GSR) unique elements (PbBaSb). The obtained data about the definition of characteristic GSR particles was concordant with other studies on this topic.

FIB-SEM imaging of carbon nanotubes in mouse lung tissue.

PubMed

Købler, Carsten; Saber, Anne Thoustrup; Jacobsen, Nicklas Raun; Wallin, Håkan; Vogel, Ulla; Qvortrup, Klaus; Mølhave, Kristian

2014-06-01

Ultrastructural characterisation is important for understanding carbon nanotube (CNT) toxicity and how the CNTs interact with cells and tissues. The standard method for this involves using transmission electron microscopy (TEM). However, in particular, the sample preparation, using a microtome to cut thin sample sections for TEM, can be challenging for investigation of regions with agglomerations of large and stiff CNTs because the CNTs cut with difficulty. As a consequence, the sectioning diamond knife may be damaged and the uncut CNTs are left protruding from the embedded block surface excluding them from TEM analysis. To provide an alternative to ultramicrotomy and subsequent TEM imaging, we studied focused ion beam scanning electron microscopy (FIB-SEM) of CNTs in the lungs of mice, and we evaluated the applicability of the method compared to TEM. FIB-SEM can provide serial section volume imaging not easily obtained with TEM, but it is time-consuming to locate CNTs in the tissue. We demonstrate that protruding CNTs after ultramicrotomy can be used to locate the region of interest, and we present FIB-SEM images of CNTs in lung tissue. FIB-SEM imaging was applied to lung tissue from mice which had been intratracheally instilled with two different multiwalled CNTs; one being short and thin, and the other longer and thicker. FIB-SEM was found to be most suitable for detection of the large CNTs (Ø ca. 70 nm), and to be well suited for studying CNT agglomerates in biological samples which is challenging using standard TEM techniques.

GPU accelerated Monte-Carlo simulation of SEM images for metrology

NASA Astrophysics Data System (ADS)

Verduin, T.; Lokhorst, S. R.; Hagen, C. W.

2016-03-01

In this work we address the computation times of numerical studies in dimensional metrology. In particular, full Monte-Carlo simulation programs for scanning electron microscopy (SEM) image acquisition are known to be notoriously slow. Our quest in reducing the computation time of SEM image simulation has led us to investigate the use of graphics processing units (GPUs) for metrology. We have succeeded in creating a full Monte-Carlo simulation program for SEM images, which runs entirely on a GPU. The physical scattering models of this GPU simulator are identical to a previous CPU-based simulator, which includes the dielectric function model for inelastic scattering and also refinements for low-voltage SEM applications. As a case study for the performance, we considered the simulated exposure of a complex feature: an isolated silicon line with rough sidewalls located on a at silicon substrate. The surface of the rough feature is decomposed into 408 012 triangles. We have used an exposure dose of 6 mC/cm2, which corresponds to 6 553 600 primary electrons on average (Poisson distributed). We repeat the simulation for various primary electron energies, 300 eV, 500 eV, 800 eV, 1 keV, 3 keV and 5 keV. At first we run the simulation on a GeForce GTX480 from NVIDIA. The very same simulation is duplicated on our CPU-based program, for which we have used an Intel Xeon X5650. Apart from statistics in the simulation, no difference is found between the CPU and GPU simulated results. The GTX480 generates the images (depending on the primary electron energy) 350 to 425 times faster than a single threaded Intel X5650 CPU. Although this is a tremendous speedup, we actually have not reached the maximum throughput because of the limited amount of available memory on the GTX480. Nevertheless, the speedup enables the fast acquisition of simulated SEM images for metrology. We now have the potential to investigate case studies in CD-SEM metrology, which otherwise would take unreasonable

Application of the SEM to the measurement of solar cell parameters

NASA Technical Reports Server (NTRS)

Weizer, V. G.; Andrews, C. W.

1977-01-01

Techniques are described which make use of the SEM to measure the minority carrier diffusion length and the metallurgical junction depth in silicon solar cells. The former technique permits the measurement of the true bulk diffusion length through the application of highly doped field layers to the back surfaces of the cells being investigated. It is shown that the secondary emission contrast observed in the SEM on a reverse-biased diode can depict the location of the metallurgical junction if the diode has been prepared with the proper beveled geometry. The SEM provides the required contrast and the option of high magnification, permitting the measurement of extremely shallow junction depths.

Single-entry models (SEMs) for scheduled services: Towards a roadmap for the implementation of recommended practices.

PubMed

Lopatina, Elena; Damani, Zaheed; Bohm, Eric; Noseworthy, Tom W; Conner-Spady, Barbara; MacKean, Gail; Simpson, Chris S; Marshall, Deborah A

2017-09-01

Long waiting times for elective services continue to be a challenging issue. Single-entry models (SEMs) are used to increase access to and flow through the healthcare system. This paper provides a roadmap for healthcare decision-makers, managers, physicians, and researchers to guide implementation and management of successful and sustainable SEMs. The roadmap was informed by an inductive qualitative synthesis of the findings from a deliberative process (a symposium on SEMs, with clinicians, researchers, senior policy-makers, healthcare managers, and patient representatives) and focus groups with the symposium participants. SEMs are a promising strategy to improve the management of referrals and represent one approach to reduce waiting times. The SEMs roadmap outlines current knowledge about SEMs and critical success factors for SEMs' implementation and management. This SEM roadmap is intended to help clinicians, decision-makers, managers, and researchers interested in developing new or strengthening existing SEMs. We consider this roadmap to be a living document that will continue to evolve as we learn more about implementing and managing sustainable SEMs. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of surfactant types and their concentration on the structural characteristics of nanoclay

NASA Astrophysics Data System (ADS)

Zawrah, M. F.; Khattab, R. M.; Saad, E. M.; Gado, R. A.

2014-03-01

A series of organo-modified nanoclays was synthesized using three different surfactants having different alkyl chain lengths and concentrations [0.5-5.0 cation exchange capacity (CEC)]. These surfactants were Ethanolamine (EA), Cetyltrimethylammoniumbromide (CTAB) and Tetraoctadecylammoniumbromide (TO). The obtained modified nanoclays were characterized by X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) and compared with unmodified nanoclay. The results of XRD analysis indicated that the basal d-spacing has increased with increasing alkyl chain length and surfactant concentration. From the obtained microstructures of these organo-modified nanoclays, the mechanism of surfactant adsorption was proposed. At relatively low loading of surfactant, most of surfactant entered the spacing by an ion-exchange mechanism and is adsorbed onto the interlayer cation sites. When the concentration of the surfactant exceeds the CEC of clay, the surfactant molecules then adhere to the surface adsorbed surfactant. Some surfactants entered the interlayers, whereas the others were attached to the clay surface. When the concentration of surfactant increased further beyond 2.0 CEC, the surfactants might occupy the inter-particle space within the house-of-cards aggregate structure.

[Sem: a suitable statistical software adaptated for research in oncology].

PubMed

Kwiatkowski, F; Girard, M; Hacene, K; Berlie, J

2000-10-01

Many softwares have been adapted for medical use; they rarely enable conveniently both data management and statistics. A recent cooperative work ended up in a new software, Sem (Statistics Epidemiology Medicine), which allows data management of trials and, as well, statistical treatments on them. Very convenient, it can be used by non professional in statistics (biologists, doctors, researchers, data managers), since usually (excepted with multivariate models), the software performs by itself the most adequate test, after what complementary tests can be requested if needed. Sem data base manager (DBM) is not compatible with usual DBM: this constitutes a first protection against loss of privacy. Other shields (passwords, cryptage...) strengthen data security, all the more necessary today since Sem can be run on computers nets. Data organization enables multiplicity: forms can be duplicated by patient. Dates are treated in a special but transparent manner (sorting, date and delay calculations...). Sem communicates with common desktop softwares, often with a simple copy/paste. So, statistics can be easily performed on data stored in external calculation sheets, and slides by pasting graphs with a single mouse click (survival curves...). Already used over fifty places in different hospitals for daily work, this product, combining data management and statistics, appears to be a convenient and innovative solution.

High resolution SEM characterization of nano-precipitates in ODS steels.

PubMed

Jóźwik, Iwona; Strojny-Nędza, Agata; Chmielewski, Marcin; Pietrzak, Katarzyna; Kurpaska, Łukasz; Nosewicz, Szymon

2018-05-01

The performance of the present-day scanning electron microscopy (SEM) extends far beyond delivering electronic images of the surface topography. Oxide dispersion strengthened (ODS) steel is on of the most promising materials for the future nuclear fusion reactor because of its good radiation resistance, and higher operation temperature up to 750°C. The microstructure of ODS should not exceed tens of nm, therefore there is a strong need in a fast and reliable technique for their characterization. In this work, the results of low-kV SEM characterization of nanoprecipitates formed in the ODS matrix are presented. Application of highly sensitive photo-diode BSE detector in SEM imaging allowed for the registration of single nm-sized precipitates in the vicinity of the ODS alloys. The composition of the precipitates has been confirmed by TEM-EDS. © 2018 Wiley Periodicals, Inc.

A brief discussion about image quality and SEM methods for quantitative fractography of polymer composites.

PubMed

Hein, L R O; Campos, K A; Caltabiano, P C R O; Kostov, K G

2013-01-01

The methodology for fracture analysis of polymeric composites with scanning electron microscopes (SEM) is still under discussion. Many authors prefer to use sputter coating with a conductive material instead of applying low-voltage (LV) or variable-pressure (VP) methods, which preserves the original surfaces. The present work examines the effects of sputter coating with 25 nm of gold on the topography of carbon-epoxy composites fracture surfaces, using an atomic force microscope. Also, the influence of SEM imaging parameters on fractal measurements is evaluated for the VP-SEM and LV-SEM methods. It was observed that topographic measurements were not significantly affected by the gold coating at tested scale. Moreover, changes on SEM setup leads to nonlinear outcome on texture parameters, such as fractal dimension and entropy values. For VP-SEM or LV-SEM, fractal dimension and entropy values did not present any evident relation with image quality parameters, but the resolution must be optimized with imaging setup, accompanied by charge neutralization. © Wiley Periodicals, Inc.

Minimal resin embedding of multicellular specimens for targeted FIB-SEM imaging.

PubMed

Schieber, Nicole L; Machado, Pedro; Markert, Sebastian M; Stigloher, Christian; Schwab, Yannick; Steyer, Anna M

2017-01-01

Correlative light and electron microscopy (CLEM) is a powerful tool to perform ultrastructural analysis of targeted tissues or cells. The large field of view of the light microscope (LM) enables quick and efficient surveys of the whole specimen. It is also compatible with live imaging, giving access to functional assays. CLEM protocols take advantage of the features to efficiently retrace the position of targeted sites when switching from one modality to the other. They more often rely on anatomical cues that are visible both by light and electron microscopy. We present here a simple workflow where multicellular specimens are embedded in minimal amounts of resin, exposing their surface topology that can be imaged by scanning electron microscopy (SEM). LM and SEM both benefit from a large field of view that can cover whole model organisms. As a result, targeting specific anatomic locations by focused ion beam-SEM (FIB-SEM) tomography becomes straightforward. We illustrate this application on three different model organisms, used in our laboratory: the zebrafish embryo Danio rerio, the marine worm Platynereis dumerilii, and the dauer larva of the nematode Caenorhabditis elegans. Here we focus on the experimental steps to reduce the amount of resin covering the samples and to image the specimens inside an FIB-SEM. We expect this approach to have widespread applications for volume electron microscopy on multiple model organisms. Copyright © 2017 Elsevier Inc. All rights reserved.

Viewing Integrated-Circuit Interconnections By SEM

NASA Technical Reports Server (NTRS)

Lawton, Russel A.; Gauldin, Robert E.; Ruiz, Ronald P.

1990-01-01

Back-scattering of energetic electrons reveals hidden metal layers. Experiment shows that with suitable operating adjustments, scanning electron microscopy (SEM) used to look for defects in aluminum interconnections in integrated circuits. Enables monitoring, in situ, of changes in defects caused by changes in temperature. Gives truer picture of defects, as etching can change stress field of metal-and-passivation pattern, causing changes in defects.

Feature evaluation of complex hysteresis smoothing and its practical applications to noisy SEM images.

PubMed

Suzuki, Kazuhiko; Oho, Eisaku

2013-01-01

Quality of a scanning electron microscopy (SEM) image is strongly influenced by noise. This is a fundamental drawback of the SEM instrument. Complex hysteresis smoothing (CHS) has been previously developed for noise removal of SEM images. This noise removal is performed by monitoring and processing properly the amplitude of the SEM signal. As it stands now, CHS may not be so utilized, though it has several advantages for SEM. For example, the resolution of image processed by CHS is basically equal to that of the original image. In order to find wide application of the CHS method in microscopy, the feature of CHS, which has not been so clarified until now is evaluated correctly. As the application of the result obtained by the feature evaluation, cursor width (CW), which is the sole processing parameter of CHS, is determined more properly using standard deviation of noise Nσ. In addition, disadvantage that CHS cannot remove the noise with excessively large amplitude is improved by a certain postprocessing. CHS is successfully applicable to SEM images with various noise amplitudes. © Wiley Periodicals, Inc.

Enhanced FIB-SEM systems for large-volume 3D imaging

DOE PAGES

Xu, C. Shan; Hayworth, Kenneth J.; Lu, Zhiyuan; ...

2017-05-13

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 10 6 ?m 3 . These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processesmore » and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology.« less

Enhanced FIB-SEM systems for large-volume 3D imaging.

PubMed

Xu, C Shan; Hayworth, Kenneth J; Lu, Zhiyuan; Grob, Patricia; Hassan, Ahmed M; García-Cerdán, José G; Niyogi, Krishna K; Nogales, Eva; Weinberg, Richard J; Hess, Harald F

2017-05-13

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 10 6 µm 3 . These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processes and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology.

Multi-scale characterization by FIB-SEM/TEM/3DAP.

PubMed

Ohkubo, T; Sepehri-Amin, H; Sasaki, T T; Hono, K

2014-11-01

In order to improve properties of functional materials, it is important to understand the relation between the structure and the properties since the structure has large effect to the properties. This can be done by using multi-scale microstructure analysis from macro-scale to nano and atomic scale. Scanning electron microscope (SEM) equipped with focused ion beam (FIB), transmission electron microscope (TEM) and 3D atom probe (3DAP) are complementary analysis tools making it possible to know the structure and the chemistry from micron to atomic resolution. SEM gives us overall microstructural and chemical information by various kinds of detectors such as secondary electron, backscattered electron, EDS and EBSD detectors. Also, it is possible to analyze 3D structure and chemistry via FIB serial sectioning. In addition, using TEM we can focus on desired region to get more complementary information from HRTEM/STEM/Lorentz images, SAED/NBD patterns and EDS/EELS to see the detail micro or nano-structure and chemistry. Especially, combination of probe Cs corrector and split EDS detectors with large detector size enable us to analyze the atomic scale elemental distribution. Furthermore, if the specimen has a complicated 3D nanostructure, or we need to analyze light elements such as hydrogen, lithium or boron, 3DAP can be used as the only technique which can visualize and analyze distribution of all constituent atoms of our materials within a few hundreds nm area. Hence, site-specific sample preparation using FIB/SEM is necessary to get desired information from region of interest. Therefore, this complementary analysis combination works very well to understand the detail of materials.In this presentation, we will show the analysis results obtained from some of functional materials by Carl Zeiss CrossBeam 1540EsB FIB/SEM, FEI Tecnai G(2) F30, Titan G2 80-200 TEMs and locally build laser assisted 3DAP. As the one of the example, result of multi-scale characterization for

Some Esoteric Aspects of SEM that Its Practitioners Should Want to Know

ERIC Educational Resources Information Center

Rozeboom, William W.

2009-01-01

The topic of this article is the interpretation of structural equation modeling (SEM) solutions. Its purpose is to augment structural modeling's metatheoretic resources while enhancing awareness of how problematic is the causal significance of SEM-parameter solutions. Part I focuses on the nonuniqueness and consequent dubious interpretability of…

Evaluation of an Approximate Method for Synthesizing Covariance Matrices for Use in Meta-Analytic SEM

ERIC Educational Resources Information Center

Beretvas, S. Natasha; Furlow, Carolyn F.

2006-01-01

Meta-analytic structural equation modeling (MA-SEM) is increasingly being used to assess model-fit for variables' interrelations synthesized across studies. MA-SEM researchers have analyzed synthesized correlation matrices using structural equation modeling (SEM) estimation that is designed for covariance matrices. This can produce incorrect…

Information or resolution: Which is required from an SEM to study bulk inorganic materials?

PubMed

Xing, Q

2016-11-01

Significant technological advances in scanning electron microscopy (SEM) have been achieved over the past years. Different SEMs can have significant differences in functionality and performance. This work presents the perspectives on selecting an SEM for research on bulk inorganic materials. Understanding materials demands quantitative composition and orientation information, and informative and interpretable images that reveal subtle differences in chemistry, orientation/structure, topography, and electronic structure. The capability to yield informative and interpretable images with high signal-to-noise ratios and spatial resolutions is an overall result of the SEM system as a whole, from the electron optical column to the detection system. The electron optical column determines probe performance. The roles of the detection system are to capture, filter or discriminate, and convert signal electrons to imaging information. The capability to control practical operating parameters including electron probe size and current, acceleration voltage or landing voltage, working distance, detector selection, and signal filtration is inherently determined by the SEM itself. As a platform for various accessories, e.g. an energy-dispersive spectrometer and an electron backscatter diffraction detector, the properties of the electron optical column, specimen chamber, and stage greatly affect the performance of accessories. Ease-of-use and ease-of-maintenance are of practical importance. It is practically important to select appropriate test specimens, design suitable imaging conditions, and analyze the specimen chamber geometry and dimensions to assess the overall functionality and performance of an SEM. For an SEM that is controlled/operated with a computer, the stable software and user-friendly interface significantly improve the usability of the SEM. SCANNING 38:864-879, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Surface topography characterization using 3D stereoscopic reconstruction of SEM images

NASA Astrophysics Data System (ADS)

Vedantha Krishna, Amogh; Flys, Olena; Reddy, Vijeth V.; Rosén, B. G.

2018-06-01

A major drawback of the optical microscope is its limitation to resolve finer details. Many microscopes have been developed to overcome the limitations set by the diffraction of visible light. The scanning electron microscope (SEM) is one such alternative: it uses electrons for imaging, which have much smaller wavelength than photons. As a result high magnification with superior image resolution can be achieved. However, SEM generates 2D images which provide limited data for surface measurements and analysis. Often many research areas require the knowledge of 3D structures as they contribute to a comprehensive understanding of microstructure by allowing effective measurements and qualitative visualization of the samples under study. For this reason, stereo photogrammetry technique is employed to convert SEM images into 3D measurable data. This paper aims to utilize a stereoscopic reconstruction technique as a reliable method for characterization of surface topography. Reconstructed results from SEM images are compared with coherence scanning interferometer (CSI) results obtained by measuring a roughness reference standard sample. This paper presents a method to select the most robust/consistent surface texture parameters that are insensitive to the uncertainties involved in the reconstruction technique itself. Results from the two-stereoscopic reconstruction algorithms are also documented in this paper.

Application of the SEM to the measurement of solar cell parameters

NASA Technical Reports Server (NTRS)

Weizer, V. G.; Andrews, C. W.

1977-01-01

A pair of techniques are described which make use of the SEM to measure, respectively, the minority carrier diffusion length and the metallurgical junction depth in silicon solar cells. The former technique permits the measurement of the true bulk diffusion length through the application of highly doped field layers to the back surfaces of the cells being investigated. The technique yields an absolute value of the diffusion length from a knowledge of the collected fraction of the injected carriers and the cell thickness. It is shown that the secondary emission contrast observed in the SEM on a reverse-biased diode can depict the location of the metallurgical junction if the diode has been prepared with the proper beveled geometry. The SEM provides the required contrast and the option of high magnification, permitting the measurement of extremely shallow junction depths.

The SEM description of interaction of a transient electromagnetic wave with an object

NASA Technical Reports Server (NTRS)

Pearson, L. W.; Wilton, D. R.

1980-01-01

The singularity expansion method (SEM), proposed as a means for determining and representing the transient surface current density induced on a scatterer by a transient electromagnetic wave is described. The resulting mathematical description of the transient surface current on the object is discussed. The data required to represent the electromagnetic scattering properties of a given object are examined. Experimental methods which were developed for the determination of the SEM description are discussed. The feasibility of characterizing the surface current induced on aircraft flying in proximity to a lightning stroke by way of SEM is examined.

3D imaging of cells and tissues by focused ion beam/scanning electron microscopy (FIB/SEM).

PubMed

Drobne, Damjana

2013-01-01

Integration of a scanning electron microscope (SEM) and focused ion beam (FIB) technology into a single FIB/SEM system permits use of the FIB as a nano-scalpel to reveal site-specific subsurface microstructures which can be examined in great detail by SEM. The FIB/SEM technology is widely used in the semiconductor industry and material sciences, and recently its use in the life sciences has been initiated. Samples for FIB/SEM investigation can be either embedded in a plastic matrix, the traditional means of preparation of transmission electron microscopy (TEM) specimens, or simply dried as in samples prepared for SEM imaging. Currently, FIB/SEM is used in the life sciences for (a) preparation by the lift-out technique of lamella for TEM analysis, (b) tomography of samples embedded in a matrix, and (c) in situ site-specific FIB milling and SEM imaging using a wide range of magnifications. Site-specific milling and imaging has attracted wide interest as a technique in structural research of single eukaryotic and prokaryotic cells, small animals, and different animal tissue, but it still remains to be explored more thoroughly. In the past, preparation of samples for site-specific milling and imaging by FIB/SEM has typically adopted the embedding techniques used for TEM samples, and which have been very well described in the literature. Sample preparation protocols for the use of dried samples in FIB/SEM have been less well investigated. The aim of this chapter is to encourage application of FIB/SEM on dried biological samples. A detailed description of conventional dried sample preparation and FIB/SEM investigation of dried biological samples is presented. The important steps are described and illustrated, and direct comparison between embedded and dried samples of same tissues is provided. The ability to discover links between gross morphology of the tissue or organ, surface characteristics of any selected region, and intracellular structural details on the nanometer

Enhanced FIB-SEM systems for large-volume 3D imaging

PubMed Central

Xu, C Shan; Hayworth, Kenneth J; Lu, Zhiyuan; Grob, Patricia; Hassan, Ahmed M; García-Cerdán, José G; Niyogi, Krishna K; Nogales, Eva; Weinberg, Richard J; Hess, Harald F

2017-01-01

Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 106 µm3. These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processes and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology. DOI: http://dx.doi.org/10.7554/eLife.25916.001 PMID:28500755

Automated Transmission-Mode Scanning Electron Microscopy (tSEM) for Large Volume Analysis at Nanoscale Resolution

PubMed Central

Kuwajima, Masaaki; Mendenhall, John M.; Lindsey, Laurence F.; Harris, Kristen M.

2013-01-01

Transmission-mode scanning electron microscopy (tSEM) on a field emission SEM platform was developed for efficient and cost-effective imaging of circuit-scale volumes from brain at nanoscale resolution. Image area was maximized while optimizing the resolution and dynamic range necessary for discriminating key subcellular structures, such as small axonal, dendritic and glial processes, synapses, smooth endoplasmic reticulum, vesicles, microtubules, polyribosomes, and endosomes which are critical for neuronal function. Individual image fields from the tSEM system were up to 4,295 µm2 (65.54 µm per side) at 2 nm pixel size, contrasting with image fields from a modern transmission electron microscope (TEM) system, which were only 66.59 µm2 (8.160 µm per side) at the same pixel size. The tSEM produced outstanding images and had reduced distortion and drift relative to TEM. Automated stage and scan control in tSEM easily provided unattended serial section imaging and montaging. Lens and scan properties on both TEM and SEM platforms revealed no significant nonlinear distortions within a central field of ∼100 µm2 and produced near-perfect image registration across serial sections using the computational elastic alignment tool in Fiji/TrakEM2 software, and reliable geometric measurements from RECONSTRUCT™ or Fiji/TrakEM2 software. Axial resolution limits the analysis of small structures contained within a section (∼45 nm). Since this new tSEM is non-destructive, objects within a section can be explored at finer axial resolution in TEM tomography with current methods. Future development of tSEM tomography promises thinner axial resolution producing nearly isotropic voxels and should provide within-section analyses of structures without changing platforms. Brain was the test system given our interest in synaptic connectivity and plasticity; however, the new tSEM system is readily applicable to other biological systems. PMID:23555711

Measurement of pattern roughness and local size variation using CD-SEM: current status

NASA Astrophysics Data System (ADS)

Fukuda, Hiroshi; Kawasaki, Takahiro; Kawada, Hiroki; Sakai, Kei; Kato, Takashi; Yamaguchi, Satoru; Ikota, Masami; Momonoi, Yoshinori

2018-03-01

Measurement of line edge roughness (LER) is discussed from four aspects: edge detection, PSD prediction, sampling strategy, and noise mitigation, and general guidelines and practical solutions for LER measurement today are introduced. Advanced edge detection algorithms such as wave-matching method are shown effective for robustly detecting edges from low SNR images, while conventional algorithm with weak filtering is still effective in suppressing SEM noise and aliasing. Advanced PSD prediction method such as multi-taper method is effective in suppressing sampling noise within a line edge to analyze, while number of lines is still required for suppressing line to line variation. Two types of SEM noise mitigation methods, "apparent noise floor" subtraction method and LER-noise decomposition using regression analysis are verified to successfully mitigate SEM noise from PSD curves. These results are extended to LCDU measurement to clarify the impact of SEM noise and sampling noise on LCDU.

Nano-amylose-2,3-bis(3,5-dimethylphenylcarbamate)-silica hybrid sol immobilized on open tubular capillary column for capillary electrochromatography enantioseparation.

PubMed

Sun, Yaming; Wu, Qi; Shi, Xiaofeng; Gao, Jie; Dong, Shuqing; Zhao, Liang

2018-04-01

The chiral organic-inorganic hybrid materials can exhibit a high loading, and the chiral selector nanoparticles can create efficient stationary phases for open-tubular capillary electrochromatography (OT-CEC). Hence, a novel protocol for the preparation of an OT column coated with nano-amylose-2,3-bis(3,5-dimethylphenylcarbamate) (nano-ABDMPC)-silica hybrid sol through in situ layer-by-layer self-assembly method was developed for CEC enantioseparation. By controlling the assembly cycle number of nano-ABDMPC-silica hybrid sol, a homogeneous, dense and stable coating was successfully prepared, which was confirmed by SEM and elemental analysis. As the main parameter influencing the chiral separating effect, the nano-ABDMPC bearing 3-(triethoxysilyl)propyl residues concentration was investigated. The experimental results showed that 10.0 mg/mL nano-ABDMPC bearing 3-(triethoxysilyl)propyl residues coated OT capillary column possessed chiral recognition ability toward the six enantiomers (phenylalanine, tyrosine, tryptophan, phenethyl alcohol, 1-phenyl-2-propanol, and Tröger's base) at some of the different conditions tested. Additionally, the coated OT column revealed adequate repeatability concerning run-to-run, day-to-day and column-to-column. These results demonstrated the promising applicability of nano-ABDMPC-silica hybrid sol coated OT column in CEC enantioseparations. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SEM (Symmetry Equivalent Molecules): a web-based GUI to generate and visualize the macromolecules

PubMed Central

Hussain, A. S. Z.; Kumar, Ch. Kiran; Rajesh, C. K.; Sheik, S. S.; Sekar, K.

2003-01-01

SEM, Symmetry Equivalent Molecules, is a web-based graphical user interface to generate and visualize the symmetry equivalent molecules (proteins and nucleic acids). In addition, the program allows the users to save the three-dimensional atomic coordinates of the symmetry equivalent molecules in the local machine. The widely recognized graphics program RasMol has been deployed to visualize the reference (input atomic coordinates) and the symmetry equivalent molecules. This program is written using CGI/Perl scripts and has been interfaced with all the three-dimensional structures (solved using X-ray crystallography) available in the Protein Data Bank. The program, SEM, can be accessed over the World Wide Web interface at http://dicsoft2.physics.iisc.ernet.in/sem/ or http://144.16.71.11/sem/. PMID:12824326

Raman-in-SEM, a multimodal and multiscale analytical tool: performance for materials and expertise.

PubMed

Wille, Guillaume; Bourrat, Xavier; Maubec, Nicolas; Lahfid, Abdeltif

2014-12-01

The availability of Raman spectroscopy in a powerful analytical scanning electron microscope (SEM) allows morphological, elemental, chemical, physical and electronic analysis without moving the sample between instruments. This paper documents the metrological performance of the SEMSCA commercial Raman interface operated in a low vacuum SEM. It provides multiscale and multimodal analyses as Raman/EDS, Raman/cathodoluminescence or Raman/STEM (STEM: scanning transmission electron microscopy) as well as Raman spectroscopy on nanomaterials. Since Raman spectroscopy in a SEM can be influenced by several SEM-related phenomena, this paper firstly presents a comparison of this new tool with a conventional micro-Raman spectrometer. Then, some possible artefacts are documented, which are due to the impact of electron beam-induced contamination or cathodoluminescence contribution to the Raman spectra, especially with geological samples. These effects are easily overcome by changing or adapting the Raman spectrometer and the SEM settings and methodology. The deletion of the adverse effect of cathodoluminescence is solved by using a SEM beam shutter during Raman acquisition. In contrast, this interface provides the ability to record the cathodoluminescence (CL) spectrum of a phase. In a second part, this study highlights the interest and efficiency of the coupling in characterizing micrometric phases at the same point. This multimodal approach is illustrated with various issues encountered in geosciences. Copyright © 2014 Elsevier Ltd. All rights reserved.

SD-SEM: sparse-dense correspondence for 3D reconstruction of microscopic samples.

PubMed

Baghaie, Ahmadreza; Tafti, Ahmad P; Owen, Heather A; D'Souza, Roshan M; Yu, Zeyun

2017-06-01

Scanning electron microscopy (SEM) imaging has been a principal component of many studies in biomedical, mechanical, and materials sciences since its emergence. Despite the high resolution of captured images, they remain two-dimensional (2D). In this work, a novel framework using sparse-dense correspondence is introduced and investigated for 3D reconstruction of stereo SEM images. SEM micrographs from microscopic samples are captured by tilting the specimen stage by a known angle. The pair of SEM micrographs is then rectified using sparse scale invariant feature transform (SIFT) features/descriptors and a contrario RANSAC for matching outlier removal to ensure a gross horizontal displacement between corresponding points. This is followed by dense correspondence estimation using dense SIFT descriptors and employing a factor graph representation of the energy minimization functional and loopy belief propagation (LBP) as means of optimization. Given the pixel-by-pixel correspondence and the tilt angle of the specimen stage during the acquisition of micrographs, depth can be recovered. Extensive tests reveal the strength of the proposed method for high-quality reconstruction of microscopic samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

X-ray microscopy using reflection targets based on SEM with tungsten filament

NASA Astrophysics Data System (ADS)

Liu, Junbiao; Ma, Yutian; Zhao, Weixia; Niu, Geng; Chu, Mingzhang; Yin, Bohua; Han, Li; Liu, Baodong

2016-10-01

X-ray MicroandNano imaging is developed based on the conventional x-ray tomography, it can not only provide nondestructive testing with higher resolution measurement, but also be used to examine the material or the structure with low atomic number and low density. The source with micro-focal spot size is one of the key components of x-ray MicroandNano imaging. The focused electron beam from SEM bombarding the metal target can generate x-ray with ultra-small size. It is convenient to set up x-ray microscopy based on SEM for laboratory use. This paper describes a new x-ray microscopy using reflection targets based on FEI Quanta600 SEM with tungsten filament. The flat panel detector is placed outside of the vacuum chamber with 300μm thickness Be-window to isolate vacuum from the air. A stage with 3 DOFs is added to adjust the positions of the target, the SEM's sample stage is used to move sample. And the shape of target is designed as cone with 60° half cone angle to get the maximum x-ray dosage. The attenuation coefficient of Bewindow for x-ray is about 25%. Finally, the line pair card is used to evaluate the resolution and the result shows that the resolution of the system can receive less than 750nm, when the acceleration voltage is 30keV, the beam current is 160nA, the SEM working distance is 5mm and the acquisition time of the detector is 60s.

30 CFR 250.1909 - What are management's general responsibilities for the SEMS program?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE... performance of the SEMS program. (d) At intervals specified in the SEMS program and at least annually, review... the observations, conclusions and recommendations of that review. (e) Develop and endorse a written...

Enabling CD SEM metrology for 5nm technology node and beyond

NASA Astrophysics Data System (ADS)

Lorusso, Gian Francesco; Ohashi, Takeyoshi; Yamaguchi, Astuko; Inoue, Osamu; Sutani, Takumichi; Horiguchi, Naoto; Bömmels, Jürgen; Wilson, Christopher J.; Briggs, Basoene; Tan, Chi Lim; Raymaekers, Tom; Delhougne, Romain; Van den Bosch, Geert; Di Piazza, Luca; Kar, Gouri Sankar; Furnémont, Arnaud; Fantini, Andrea; Donadio, Gabriele Luca; Souriau, Laurent; Crotti, Davide; Yasin, Farrukh; Appeltans, Raf; Rao, Siddharth; De Simone, Danilo; Rincon Delgadillo, Paulina; Leray, Philippe; Charley, Anne-Laure; Zhou, Daisy; Veloso, Anabela; Collaert, Nadine; Hasumi, Kazuhisa; Koshihara, Shunsuke; Ikota, Masami; Okagawa, Yutaka; Ishimoto, Toru

2017-03-01

The CD SEM (Critical Dimension Scanning Electron Microscope) is one of the main tools used to estimate Critical Dimension (CD) in semiconductor manufacturing nowadays, but, as all metrology tools, it will face considerable challenges to keep up with the requirements of the future technology nodes. The root causes of these challenges are not uniquely related to the shrinking CD values, as one might expect, but to the increase in complexity of the devices in terms of morphology and chemical composition as well. In fact, complicated threedimensional device architectures, high aspect ratio features, and wide variety of materials are some of the unavoidable characteristics of the future metrology nodes. This means that, beside an improvement in resolution, it is critical to develop a CD SEM metrology capable of satisfying the specific needs of the devices of the nodes to come, needs that sometimes will have to be addressed through dramatic changes in approach with respect to traditional CD SEM metrology. In this paper, we report on the development of advanced CD SEM metrology at imec on a variety of device platform and processes, for both logic and memories. We discuss newly developed approaches for standard, IIIV, and germanium FinFETs (Fin Field Effect Transistors), for lateral and vertical nanowires (NW), 3D NAND (three-dimensional NAND), STT-MRAM (Spin Transfer Magnetic Torque Random-Access Memory), and ReRAM (Resistive Random Access Memory). Applications for both front-end of line (FEOL) and back-end of line (BEOL) are developed. In terms of process, S/D Epi (Source Drain Epitaxy), SAQP (Self-Aligned Quadruple Patterning), DSA (Dynamic Self-Assembly), and EUVL (Extreme Ultraviolet Lithography) have been used. The work reported here has been performed on Hitachi CG5000, CG6300, and CV5000. In terms of logic, we discuss here the S/D epi defect classification, the metrology optimization for STI (Shallow Trench Isolation) Ge FinFETs, the defectivity of III-V STI Fin

Mathematical model of the seismic electromagnetic signals (SEMS) in non crystalline substances

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

Dennis, L. C. C.; Yahya, N.; Daud, H.

The mathematical model of seismic electromagnetic waves in non crystalline substances is developed and the solutions are discussed to show the possibility of improving the electromagnetic waves especially the electric field. The shear stress of the medium in fourth order tensor gives the equation of motion. Analytic methods are selected for the solutions written in Hansen vector form. From the simulated SEMS, the frequency of seismic waves has significant effects to the SEMS propagating characteristics. EM waves transform into SEMS or energized seismic waves. Traveling distance increases once the frequency of the seismic waves increases from 100% to 1000%. SEMSmore » with greater seismic frequency will give seismic alike waves but greater energy is embedded by EM waves and hence further distance the waves travel.« less

30 CFR 250.1909 - What are management's general responsibilities for the SEMS program?

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL... intervals specified in the SEMS program and at least annually, review the SEMS program to determine if it... recommendations of that review. (e) Develop and endorse a written description of your safety and environmental...

30 CFR 250.1909 - What are management's general responsibilities for the SEMS program?

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL... intervals specified in the SEMS program and at least annually, review the SEMS program to determine if it... recommendations of that review. (e) Develop and endorse a written description of your safety and environmental...

30 CFR 250.1909 - What are management's general responsibilities for the SEMS program?

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL... intervals specified in the SEMS program and at least annually, review the SEMS program to determine if it... recommendations of that review. (e) Develop and endorse a written description of your safety and environmental...

Resolving Differences in Absolute Irradiance Measurements Between the SOHO/CELIAS/SEM and the SDO/EVE.

PubMed

Wieman, S R; Didkovsky, L V; Judge, D L

The Solar EUV Monitor (SEM) onboard SOHO has measured absolute extreme ultraviolet (EUV) and soft X-ray solar irradiance nearly continuously since January 1996. The EUV Variability Experiment (EVE) on SDO, in operation since April of 2010, measures solar irradiance in a wide spectral range that encompasses the band passes (26 - 34 nm and 0.1 - 50 nm) measured by SOHO/SEM. However, throughout the mission overlap, irradiance values from these two instruments have differed by more than the combined stated uncertainties of the measurements. In an effort to identify the sources of these differences and eliminate them, we investigate in this work the effect of reprocessing the SEM data using a more accurate SEM response function (obtained from synchrotron measurements with a SEM sounding-rocket clone instrument taken after SOHO was already in orbit) and time-dependent, measured solar spectral distributions - i.e ., solar reference spectra that were unavailable prior to the launch of the SDO. We find that recalculating the SEM data with these improved parameters reduces mean differences with the EVE measurements from about 20 % to less than 5 % in the 26 - 34 nm band, and from about 35 % to about 15 % for irradiances in the 0.1 - 7 nm band extracted from the SEM 0.1 - 50 nm channel.

A semantic proteomics dashboard (SemPoD) for data management in translational research.

PubMed

Jayapandian, Catherine P; Zhao, Meng; Ewing, Rob M; Zhang, Guo-Qiang; Sahoo, Satya S

2012-01-01

One of the primary challenges in translational research data management is breaking down the barriers between the multiple data silos and the integration of 'omics data with clinical information to complete the cycle from the bench to the bedside. The role of contextual metadata, also called provenance information, is a key factor ineffective data integration, reproducibility of results, correct attribution of original source, and answering research queries involving "What", "Where", "When", "Which", "Who", "How", and "Why" (also known as the W7 model). But, at present there is limited or no effective approach to managing and leveraging provenance information for integrating data across studies or projects. Hence, there is an urgent need for a paradigm shift in creating a "provenance-aware" informatics platform to address this challenge. We introduce an ontology-driven, intuitive Semantic Proteomics Dashboard (SemPoD) that uses provenance together with domain information (semantic provenance) to enable researchers to query, compare, and correlate different types of data across multiple projects, and allow integration with legacy data to support their ongoing research. The SemPoD platform, currently in use at the Case Center for Proteomics and Bioinformatics (CPB), consists of three components: (a) Ontology-driven Visual Query Composer, (b) Result Explorer, and (c) Query Manager. Currently, SemPoD allows provenance-aware querying of 1153 mass-spectrometry experiments from 20 different projects. SemPod uses the systems molecular biology provenance ontology (SysPro) to support a dynamic query composition interface, which automatically updates the components of the query interface based on previous user selections and efficiently prunes the result set usinga "smart filtering" approach. The SysPro ontology re-uses terms from the PROV-ontology (PROV-O) being developed by the World Wide Web Consortium (W3C) provenance working group, the minimum information required for

Why semicarbazide (SEM) is not an appropriate marker for the usage of nitrofurazone on agricultural animals.

PubMed

Stadler, Richard H; Verzegnassi, Ludovica; Seefelder, Walburga; Racault, Lucie

2015-01-01

A comprehensive global database on semicarbazide (SEM) in foodstuffs and food ingredients is presented, with over 4000 data collected in foods such as seafood (crustaceans, fish powders), meat (beef, chicken powders), dairy products (e.g. raw milk, milk powders, whey, sweet buttermilk powder, caseinate, yoghurt, cheese), honey and other ingredients. The results provide evidence that the presence of SEM in certain dairy ingredients (whey, milk protein concentrates) is a by-product of chemical reactions taking place during the manufacturing process. Of the dairy ingredients tested (c. 2000 samples), 5.3% showed traces of SEM > 0.5 µg/kg. The highest incidence of SEM-positive samples in the dairy category were whey (powders, liquid) and milk protein concentrates (35% positive), with up to 13 µg/kg measured in a whey powder. Sweet buttermilk powder and caseinate followed, with 27% and 9.3% positives, respectively. SEM was not detected in raw milk, or in yoghurt or cheese. Of the crustacean products (shrimp and prawn powders) tested, 44% were positive for SEM, the highest value measured at 284 µg/kg. Fish powders revealed an unexpectedly high incidence of positive samples (25%); in this case, fraudulent addition of shellfish shells or carry-over during processing cannot be excluded. Overall, the data provide new insights into the occurrence of SEM (for dairy products and fish powders), substantially strengthening the arguments that SEM in certain food categories is not a conclusive marker of the use of the illegal antibiotic nitrofurazone.

Connected component analysis of review-SEM images for sub-10nm node process verification

NASA Astrophysics Data System (ADS)

Halder, Sandip; Leray, Philippe; Sah, Kaushik; Cross, Andrew; Parisi, Paolo

2017-03-01

Analysis of hotspots is becoming more and more critical as we scale from node to node. To define true process windows at sub-14 nm technology nodes, often defect inspections are being included to weed out design weak spots (often referred to as hotspots). Defect inspection sub 28 nm nodes is a two pass process. Defect locations identified by optical inspection tools need to be reviewed by review-SEM's to understand exactly which feature is failing in the region flagged by the optical tool. The images grabbed by the review-SEM tool are used for classification but rarely for quantification. The goal of this paper is to see if the thousands of review-SEM images which are existing can be used for quantification and further analysis. More specifically we address the SEM quantification problem with connected component analysis.

Performance of SEM scintillation detector evaluated by modulation transfer function and detective quantum efficiency function.

PubMed

Bok, Jan; Schauer, Petr

2014-01-01

In the paper, the SEM detector is evaluated by the modulation transfer function (MTF) which expresses the detector's influence on the SEM image contrast. This is a novel approach, since the MTF was used previously to describe only the area imaging detectors, or whole imaging systems. The measurement technique and calculation of the MTF for the SEM detector are presented. In addition, the measurement and calculation of the detective quantum efficiency (DQE) as a function of the spatial frequency for the SEM detector are described. In this technique, the time modulated e-beam is used in order to create well-defined input signal for the detector. The MTF and DQE measurements are demonstrated on the Everhart-Thornley scintillation detector. This detector was alternated using the YAG:Ce, YAP:Ce, and CRY18 single-crystal scintillators. The presented MTF and DQE characteristics show good imaging properties of the detectors with the YAP:Ce or CRY18 scintillator, especially for a specific type of the e-beam scan. The results demonstrate the great benefit of the description of SEM detectors using the MTF and DQE. In addition, point-by-point and continual-sweep e-beam scans in SEM were discussed and their influence on the image quality was revealed using the MTF. © 2013 Wiley Periodicals, Inc.

High resolution SEM imaging of gold nanoparticles in cells and tissues.

PubMed

Goldstein, A; Soroka, Y; Frušić-Zlotkin, M; Popov, I; Kohen, R

2014-12-01

The growing demand of gold nanoparticles in medical applications increases the need for simple and efficient characterization methods of the interaction between the nanoparticles and biological systems. Due to its nanometre resolution, modern scanning electron microscopy (SEM) offers straightforward visualization of metallic nanoparticles down to a few nanometre size, almost without any special preparation step. However, visualization of biological materials in SEM requires complicated preparation procedure, which is typically finished by metal coating needed to decrease charging artefacts and quick radiation damage of biomaterials in the course of SEM imaging. The finest conductive metal coating available is usually composed of a few nanometre size clusters, which are almost identical to the metal nanoparticles employed in medical applications. Therefore, SEM monitoring of metal nanoparticles within cells and tissues is incompatible with the conventional preparation methods. In this work, we show that charging artefacts related to non-conductive biological specimen can be successfully eliminated by placing the uncoated biological sample on a conductive substrate. By growing the cells on glass pre-coated with a chromium layer, we were able to observe the uptake of 10 nm gold nanoparticles inside uncoated and unstained macrophages and keratinocytes cells. Imaging in back scattered electrons allowed observation of gold nanoparticles located inside the cells, while imaging in secondary electron gave information on gold nanoparticles located on the surface of the cells. By mounting a skin cross-section on an improved conductive holder, consisting of a silicon substrate coated with copper, we were able to observe penetration of gold nanoparticles of only 5 nm size through the skin barrier in an uncoated skin tissue. The described method offers a convenient modification in preparation procedure for biological samples to be analyzed in SEM. The method provides high

SEM AutoAnalysis: enhancing photomask and NIL defect disposition and review

NASA Astrophysics Data System (ADS)

Schulz, Kristian; Egodage, Kokila; Tabbone, Gilles; Ehrlich, Christian; Garetto, Anthony

2017-06-01

For defect disposition and repair verification regarding printability, AIMS™ is the state of the art measurement tool in industry. With its unique capability of capturing aerial images of photomasks it is the one method that comes closest to emulating the printing behaviour of a scanner. However for nanoimprint lithography (NIL) templates aerial images cannot be applied to evaluate the success of a repair process. Hence, for NIL defect dispositioning scanning, electron microscopy (SEM) imaging is the method of choice. In addition, it has been a standard imaging method for further root cause analysis of defects and defect review on optical photomasks which enables 2D or even 3D mask profiling at high resolutions. In recent years a trend observed in mask shops has been the automation of processes that traditionally were driven by operators. This of course has brought many advantages one of which is freeing cost intensive labour from conducting repetitive and tedious work. Furthermore, it reduces variability in processes due to different operator skill and experience levels which at the end contributes to eliminating the human factor. Taking these factors into consideration, one of the software based solutions available under the FAVOR® brand to support customer needs is the aerial image evaluation software, AIMS™ AutoAnalysis (AAA). It provides fully automated analysis of AIMS™ images and runs in parallel to measurements. This is enabled by its direct connection and communication with the AIMS™tools. As one of many positive outcomes, generating automated result reports is facilitated, standardizing the mask manufacturing workflow. Today, AAA has been successfully introduced into production at multiple customers and is supporting the workflow as described above. These trends indeed have triggered the demand for similar automation with respect to SEM measurements leading to the development of SEM AutoAnalysis (SAA). It aims towards a fully automated SEM image

Enhanced EDX images by fusion of multimodal SEM images using pansharpening techniques.

PubMed

Franchi, G; Angulo, J; Moreaud, M; Sorbier, L

2018-01-01

The goal of this paper is to explore the potential interest of image fusion in the context of multimodal scanning electron microscope (SEM) imaging. In particular, we aim at merging the backscattered electron images that usually have a high spatial resolution but do not provide enough discriminative information to physically classify the nature of the sample, with energy-dispersive X-ray spectroscopy (EDX) images that have discriminative information but a lower spatial resolution. The produced images are named enhanced EDX. To achieve this goal, we have compared the results obtained with classical pansharpening techniques for image fusion with an original approach tailored for multimodal SEM fusion of information. Quantitative assessment is obtained by means of two SEM images and a simulated dataset produced by a software based on PENELOPE. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Using ICP-OES and SEM-EDX in biosorption studies

PubMed Central

Chojnacka, Katarzyna; Marycz, Krzysztof

2010-01-01

We have compared the analytical results obtained by inductively coupled plasma optical emission spectroscopy (ICP-OES) and by scanning electron microscopy with an energy dispersive X-ray analytical system (SEM-EDX) in order to explore the mechanism of metal ions biosorption by biomass using two independent methods. The marine macroalga Enteromorpha sp. was enriched with Cu(II), Mn(II), Zn(II), and Co(II) ions via biosorption, and the biosorption capacity of alga determined from the solution and biomass composition before and after biosorption process was compared. The first technique was used to analyze the composition of the natural and metal-loaded biomass, and additionally the composition of the solution before and after biosorption. The second technique was used to obtain a picture of the surface of natural and metal ion-loaded macroalgae, to map the elements on the cell wall of dry biomass, and to determine their concentration before and after biosorption. ICP-OES showed a better precision and lower detection limit than EDX, but SEM-EDX gave more information regarding the sample composition of Enteromorpha sp. Both techniques confirmed that biosorption is a surface phenomenon, in which alkali and alkaline earth metal ions were exchanged by metal ions from aqueous solution. Figure The advantages and disadvantages of ICP-OES and SEM-EDX techniques Electronic supplementary material The online version of this article (doi:10.1007/s00604-010-0468-0) contains supplementary material, which is available to authorized users. PMID:21423317

Using ICP-OES and SEM-EDX in biosorption studies.

PubMed

Michalak, Izabela; Chojnacka, Katarzyna; Marycz, Krzysztof

2011-02-01

We have compared the analytical results obtained by inductively coupled plasma optical emission spectroscopy (ICP-OES) and by scanning electron microscopy with an energy dispersive X-ray analytical system (SEM-EDX) in order to explore the mechanism of metal ions biosorption by biomass using two independent methods. The marine macroalga Enteromorpha sp. was enriched with Cu(II), Mn(II), Zn(II), and Co(II) ions via biosorption, and the biosorption capacity of alga determined from the solution and biomass composition before and after biosorption process was compared. The first technique was used to analyze the composition of the natural and metal-loaded biomass, and additionally the composition of the solution before and after biosorption. The second technique was used to obtain a picture of the surface of natural and metal ion-loaded macroalgae, to map the elements on the cell wall of dry biomass, and to determine their concentration before and after biosorption. ICP-OES showed a better precision and lower detection limit than EDX, but SEM-EDX gave more information regarding the sample composition of Enteromorpha sp. Both techniques confirmed that biosorption is a surface phenomenon, in which alkali and alkaline earth metal ions were exchanged by metal ions from aqueous solution.FigureThe advantages and disadvantages of ICP-OES and SEM-EDX techniques ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00604-010-0468-0) contains supplementary material, which is available to authorized users.

Physicochemical and functional properties of coconut (Cocos nucifera L) cake dietary fibres: Effects of cellulase hydrolysis, acid treatment and particle size distribution.

PubMed

Zheng, Yajun; Li, Yan

2018-08-15

Effects of cellulase hydrolysis, acid treatment and particle size distribution on the structure, physicochemical and functional properties of coconut cake dietary fiber (DCCDF) were studied. Results showed that both the cellulase hydrolysis and acid treatment contributed to the structural modification of DCCDF as evident from XRD, FT-IR and SEM analysis. Moreover, the cellulase hydrolysis enhanced soluble carbohydrate content, water holding capacity (WHC) and swelling capacity (WSC), α-amylase inhibition activity (α-AAIR), glucose dialysis retardation index (GDRI) and cation-exchange capacity (CEC) of DCCDF; but it had undesirable effects on colour, oil holding capacity (OHC) and emulsifying capacity (EC). On other hand, acid treatment decreased the WHC, WSC and GDRI, but improved the colour, CEC, OHC and emulsion stability of DCCDF. Furthermore, the WHC, WSC and EC of DCCDF increased as the particle size reduced from 250 to 167 μm, while the GDRI, OHC, α-AAIR and emulsion stability decreased with decreasing particle size. Copyright © 2018 Elsevier Ltd. All rights reserved.

University of Maryland MRSEC - Facilities: SEM/STM/AFM

Science.gov Websites

MRSEC Templates Opportunities Search Home » Facilities » SEM/STM/AFM Shared Experimental Facilities conducting and non conducting samples. The sample stage permits electronic device imaging under operational Specifications: Image Modes - STM, STS, MFM, EFM, SKPM, contact- and non-contact AFM Three Sample Contacts 0.1 nm

Cryo-Scanning Electron Microscopy (SEM) and Scanning Transmission Electron Microscopy (STEM)-in-SEM for Bio- and Organo-Mineral Interface Characterization in the Environment.

PubMed

Wille, Guillaume; Hellal, Jennifer; Ollivier, Patrick; Richard, Annie; Burel, Agnes; Jolly, Louis; Crampon, Marc; Michel, Caroline

2017-12-01

Understanding biofilm interactions with surrounding substratum and pollutants/particles can benefit from the application of existing microscopy tools. Using the example of biofilm interactions with zero-valent iron nanoparticles (nZVI), this study aims to apply various approaches in biofilm preparation and labeling for fluorescent or electron microscopy and energy dispersive X-ray spectrometry (EDS) microanalysis for accurate observations. According to the targeted microscopy method, biofilms were sampled as flocs or attached biofilm, submitted to labeling using 4',6-diamidino-2-phenylindol, lectins PNA and ConA coupled to fluorescent dye or gold nanoparticles, and prepared for observation (fixation, cross-section, freezing, ultramicrotomy). Fluorescent microscopy revealed that nZVI were embedded in the biofilm structure as aggregates but the resolution was insufficient to observe individual nZVI. Cryo-scanning electron microscopy (SEM) observations showed nZVI aggregates close to bacteria, but it was not possible to confirm direct interactions between nZVI and cell membranes. Scanning transmission electron microscopy in the SEM (STEM-in-SEM) showed that nZVI aggregates could enter the biofilm to a depth of 7-11 µm. Bacteria were surrounded by a ring of extracellular polymeric substances (EPS) preventing direct nZVI/membrane interactions. STEM/EDS mapping revealed a co-localization of nZVI aggregates with lectins suggesting a potential role of EPS in nZVI embedding. Thus, the combination of divergent microscopy approaches is a good approach to better understand and characterize biofilm/metal interactions.

Detailed methodology for high resolution scanning electron microscopy (SEM) of murine malaria parasitized-erythrocytes.

PubMed

Hayakawa, Eri H; Matsuoka, Hiroyuki

2016-10-01

Scanning electron microscopy (SEM) is a powerful tool used to investigate object surfaces and has been widely applied in both material science and biology. With respect to the study of malaria, SEM revealed that erythrocytes infected with Plasmodium falciparum, a human parasite, display 'knob-like' structures on their surface comprising parasitized proteins. However, detailed methodology for SEM studies of malaria parasites is lacking in the literature making such studies challenging. Here, we provide a step-by-step guide to preparing Plasmodium-infected erythrocytes from two mouse strains for SEM analysis with minimal structural deterioration. We tested three species of murine malaria parasites, P. berghei, P. yoelii, and P. chabaudi, as well as non-parasitized human erythrocytes and P. falciparum-infected erythrocytes for comparisons. Our data demonstrated that the surface structures of parasitized erythrocytes between the three species of murine parasites in the two different strains of mice were indistinguishable and no surface alterations were observed in P. falciparum-erythrocytes. Our SEM observations contribute towards an understanding of the molecular mechanisms of parasite maturation in the erythrocyte cytoplasm and, along with future studies using our detailed methodology, may help to gain insight into the clinical phenomena of human malaria. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

30 CFR 250.1924 - How will BOEMRE determine if my SEMS program is effective?

Code of Federal Regulations, 2011 CFR

2011-07-01

... protecting the safety and health of workers, the environment, and preventing incidents. BOEMRE or its..., (2) You can explain and demonstrate the procedures and policies included in your SEMS program; and (3) You can produce evidence to support the implementation of your SEMS program. (d) Representatives from...

30 CFR 250.1916 - What criteria for mechanical integrity must my SEMS program meet?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 2 2011-07-01 2011-07-01 false What criteria for mechanical integrity must my SEMS program meet? 250.1916 Section 250.1916 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT... mechanical integrity must my SEMS program meet? You must develop and implement written procedures that...

Characterization of some biological specimens using TEM and SEM

NASA Astrophysics Data System (ADS)

Ghosh, Nabarun; Smith, Don W.

2009-05-01

The advent of novel techniques using the Transmission and Scanning Electron Microscopes improved observation on various biological specimens to characterize them. We studied some biological specimens using Transmission and Scanning Electron Microscopes. We followed negative staining technique with Phosphotungstic acid using bacterial culture of Bacillus subtilis. Negative staining is very convenient technique to view the structural morphology of different samples including bacteria, phage viruses and filaments in a cell. We could observe the bacterial cell wall and flagellum very well when trapped the negative stained biofilm from bacterial culture on a TEM grid. We cut ultra thin sections from the fixed root tips of Pisum sativum (Garden pea). Root tips were pre fixed with osmium tetroxide and post fixed with uranium acetate and placed in the BEEM capsule for block making. The ultrathin sections on the grid under TEM showed the granular chromatin in the nucleus. The protein bodies and large vacuoles with the storage materials were conspicuous. We followed fixation, critical point drying and sputter coating with gold to view the tissues with SEM after placing on stubs. SEM view of the leaf surface of a dangerous weed Tragia hispida showed the surface trichomes. These trichomes when break on touching releases poisonous content causing skin irritation. The cultured tissue from in vitro culture of Albizia lebbeck, a tree revealed the regenerative structures including leaf buds and stomata on the tissue surface. SEM and TEM allow investigating the minute details characteristic morphological features that can be used for classroom teaching.

Counting Synapses Using FIB/SEM Microscopy: A True Revolution for Ultrastructural Volume Reconstruction.

PubMed

Merchán-Pérez, Angel; Rodriguez, José-Rodrigo; Alonso-Nanclares, Lidia; Schertel, Andreas; Defelipe, Javier

2009-01-01

The advent of transmission electron microscopy (TEM) in the 1950s represented a fundamental step in the study of neuronal circuits. The application of this technique soon led to the realization that the number of synapses changes during the course of normal life, as well as under certain pathological or experimental circumstances. Since then, one of the main goals in neurosciences has been to define simple and accurate methods to estimate the magnitude of these changes. Contrary to analysing single sections, TEM reconstructions are extremely time-consuming and difficult. Therefore, most quantitative studies use stereological methods to define the three-dimensional characteristics of synaptic junctions that are studied in two dimensions. Here, to count the exact number of synapses per unit of volume we have applied a new three-dimensional reconstruction method that involves the combination of focused ion beam milling and scanning electron microscopy (FIB/SEM). We show that the images obtained with FIB/SEM are similar to those obtained with TEM, but with the advantage that FIB/SEM permits serial reconstructions of large volumes of tissue to be generated rapidly and automatically. Furthermore, we compared the estimates of the number of synapses obtained with stereological methods with the values obtained by FIB/SEM reconstructions. We concluded that FIB/SEM not only provides the actual number of synapses per volume but it is also much easier and faster to use than other currently available TEM methods. More importantly, it also avoids most of the errors introduced by stereological methods and overcomes the difficulties associated with these techniques.

Carotene location in processed food samples measured by cryo In-SEM Raman.

PubMed

Lopez-Sanchez, Patricia; Schumm, Stephan; Pudney, Paul D A; Hazekamp, Johan

2011-09-21

Cryo In-SEM Raman has been used for the first time to localise carotene compounds in a food matrix. Raman spectra of lycopene and β-carotene have been obtained from sampling oil droplets and plant cell structures visualised with cryo-SEM in tomato and carrot based emulsions containing 5% oil. It was possible to identify the carotenoids in both the oil droplets and the cell walls. Furthermore our results gave some indication that the carotenoids were in the non-crystalline state. It has been suggested that a higher amount of carotenes solubilised into the oil phase of the food matrix would lead to a higher bioaccessibility, thus understanding the effect of processing conditions on micronutrients distribution in a food matrix might help the design of plant based food products with a better nutritional quality. This shows improved structural characterisation of the cryo-SEM with the molecular sensitivity of Raman spectroscopy as a promising approach for complex biological problems.

Automated SEM and TEM sample preparation applied to copper/low k materials

NASA Astrophysics Data System (ADS)

Reyes, R.; Shaapur, F.; Griffiths, D.; Diebold, A. C.; Foran, B.; Raz, E.

2001-01-01

We describe the use of automated microcleaving for preparation of both SEM and TEM samples as done by SELA's new MC500 and TEMstation tools. The MC500 is an automated microcleaving tool that is capable of producing cleaves with 0.25 μm accuracy resulting in SEM-ready samples. The TEMstation is capable of taking a sample output from the MC500 (or from SELA's earlier MC200 tool) and producing a FIB ready slice of 25±5 μm, mounted on a TEM-washer and ready for FIB thinning to electron transparency for TEM analysis. The materials selected for the tool set evaluation mainly included the Cu/TaN/HOSP low-k system. The paper is divided into three sections, experimental approach, SEM preparation and analysis of HOSP low-k, and TEM preparation and analysis of Cu/TaN/HOSP low-k samples. For the samples discussed, data is presented to show the quality of preparation provided by these new automated tools.

Application of Replica Technique and SEM in Accuracy Measurement of Ceramic Crowns

NASA Astrophysics Data System (ADS)

Trifkovic, B.; Budak, I.; Todorovic, A.; Hodolic, J.; Puskar, T.; Jevremovic, D.; Vukelic, D.

2012-01-01

The paper presents a comparative study of the measuring values of the marginal gap related to the ceramic crowns made by dental CAD/CAM system using the replica technique and SEM. The study was conducted using three experimental groups, which consisted of ceramic crowns manufactured by the Cerec CAD/CAM system. The scanning procedure was carried out using three specialized dental 3D digitization systems from the Cerec family - two types of extraoral optical scanning systems and an intraoral optical scanner. Measurements of the marginal gap were carried out using the replica technique and SEM. The comparison of aggregate values of the marginal gap using the replica technique showed a statistically significant difference between the systems. The measured values of marginal gaps of ceramic crowns using the replica technique were significantly lower compared to those measured by SEM. The results indicate that the choice of technique for measuring the accuracy of ceramic crowns influences the final results of investigation.

Soft tissue digestion of Paradiplozoon vaalense for SEM of sclerites and simultaneous molecular analysis.

PubMed

Dos Santos, Q M; Avenant-Oldewage, A

2015-02-01

Classification of most monogeneans is primarily based on size, shape, and arrangement of haptoral sclerites. These structures are often obscured or misinterpreted when studied using light microscopy, leading to confusion regarding defining characters. Scanning electron microscopy (SEM) has predominantly been used to study haptoral sclerites in smaller monogeneans, focusing on hooks and anchors. In the Diplozoidae, SEM has not been used to study haptoral sclerites. Using new and modified techniques, the sclerites of diplozoids collected in South Africa were successfully studied using SEM. The digestion buffer from a DNA extraction kit was used to digest the surrounding tissue, and Poly-L-lysine-coated and concavity slides were employed to limit the movement and loss of sclerites, with the latter being more user-friendly. In addition to the success of visualizing the sclerites using SEM, the digested tissue from as little as half of the haptor provided viable genetic material for molecular characterization. From the results presented here, the study of the sclerites of larger monogeneans using SEM, including those bearing clamps, is a viable possibility for future research. Also, this method may be beneficial for the study of other, non-haptoral sclerites, such as cirri in other families of monogeneans. During this study, Labeo capensis was noted as a valid host of Paradiplozoon vaalense in a region of the Vaal River where the type host, Labeo umbratus, appears to be absent.

Detection of glass particles on bone lesions using SEM-EDS.

PubMed

Montoriol, Romain; Guilbeau-Frugier, Céline; Chantalat, Elodie; Roumiguié, Mathieu; Delisle, Marie-Bernadette; Payré, Bruno; Telmon, Norbert; Savall, Frédéric

2017-09-01

The problem of identifying the wounding agent in forensic cases is recurrent. Moreover, when several tools are involved, distinguishing the origin of lesions can be difficult. Scanning electron microscopy (SEM)/energy dispersive X-ray analysis (EDS) equipment is increasingly available to the scientific and medical community, and some studies have reported its use in forensic anthropology. However, at our knowledge, no study has reported the use of SEM-EDS in forensic cases involving glass tools, whether in case reports or experiments. We performed an experimental study on human rib fragments, on which we manually created wounds using fragments of window and mirror glass. SEM-EDS was executed on samples without any further preparation on low vacuum mode, then on the same samples after defleshing them completely by boiling them. Window and mirror glass particles were detected on experimental wounds. Both had silica in their spectra, and the opaque side of the mirror contained titanium, allowing for their identification. Boiling and defleshing the bone samples involved a loss of information in terms of the number of wounds detected as positive for glass particles and in the number of glass particles detected, for both window and mirror glass. We suggest the analysis of wounds with suspected glass particles using low vacuum mode and with no defleshment by boiling.

Surface characteristics of isopod digestive gland epithelium studied by SEM.

PubMed

Millaku, Agron; Leser, Vladka; Drobne, Damjana; Godec, Matjaz; Torkar, Matjaz; Jenko, Monika; Milani, Marziale; Tatti, Francesco

2010-05-01

The structure of the digestive gland epithelium of a terrestrial isopod Porcellio scaber has been investigated by conventional scanning electron microscopy (SEM), focused ion beam-scanning electron microscopy (FIB/SEM), and light microscopy in order to provide evidence on morphology of the gland epithelial surface in animals from a stock culture. We investigated the shape of cells, extrusion of lipid droplets, shape and distribution of microvilli, and the presence of bacteria on the cell surface. A total of 22 animals were investigated and we found some variability in the appearance of the gland epithelial surface. Seventeen of the animals had dome-shaped digestive gland "normal" epithelial cells, which were densely and homogeneously covered by microvilli and varying proportions of which extruded lipid droplets. On the surface of microvilli we routinely observed sparsely distributed bacteria of different shapes. Five of the 22 animals had "abnormal" epithelial cells with a significantly altered shape. In three of these animals, the cells were much smaller, partly or completely flat or sometimes pyramid-like. A thick layer of bacteria was detected on the microvillous border, and in places, the shape and size of microvilli were altered. In two animals, hypertrophic cells containing large vacuoles were observed indicating a characteristic intracellular infection. The potential of SEM in morphological investigations of epithelial surfaces is discussed.

Three-dimensional ultrastructure of osteocytes assessed by focused ion beam-scanning electron microscopy (FIB-SEM).

PubMed

Hasegawa, Tomoka; Yamamoto, Tomomaya; Hongo, Hiromi; Qiu, Zixuan; Abe, Miki; Kanesaki, Takuma; Tanaka, Kawori; Endo, Takashi; de Freitas, Paulo Henrique Luiz; Li, Minqi; Amizuka, Norio

2018-04-01

The aim of this study is to demonstrate the application of focused ion beam-scanning electron microscopy, FIB-SEM for revealing the three-dimensional features of osteocytic cytoplasmic processes in metaphyseal (immature) and diaphyseal (mature) trabeculae. Tibiae of eight-week-old male mice were fixed with aldehyde solution, and treated with block staining prior to FIB-SEM observation. While two-dimensional backscattered SEM images showed osteocytes' cytoplasmic processes in a fragmented fashion, three-dimensional reconstructions of FIB-SEM images demonstrated that osteocytes in primary metaphyseal trabeculae extended their cytoplasmic processes randomly, thus maintaining contact with neighboring osteocytes and osteoblasts. In contrast, diaphyseal osteocytes extended thin cytoplasmic processes from their cell bodies, which ran perpendicular to the bone surface. In addition, these osteocytes featured thick processes that branched into thinner, transverse cytoplasmic processes; at some point, however, these transverse processes bend at a right angle to run perpendicular to the bone surface. Osteoblasts also possessed thicker cytoplasmic processes that branched off as thinner processes, which then connected with cytoplasmic processes of neighboring osteocytes. Thus, FIB-SEM is a useful technology for visualizing the three-dimensional structures of osteocytes and their cytoplasmic processes.

Investigation of hidden periodic structures on SEM images of opal-like materials using FFT and IFFT.

PubMed

Stephant, Nicolas; Rondeau, Benjamin; Gauthier, Jean-Pierre; Cody, Jason A; Fritsch, Emmanuel

2014-01-01

We have developed a method to use fast Fourier transformation (FFT) and inverse fast Fourier transformation (IFFT) to investigate hidden periodic structures on SEM images. We focused on samples of natural, play-of-color opals that diffract visible light and hence are periodically structured. Conventional sample preparation by hydrofluoric acid etch was not used; untreated, freshly broken surfaces were examined at low magnification relative to the expected period of the structural features, and, the SEM was adjusted to get a very high number of pixels in the images. These SEM images were treated by software to calculate autocorrelation, FFT, and IFFT. We present how we adjusted SEM acquisition parameters for best results. We first applied our procedure on an SEM image on which the structure was obvious. Then, we applied the same procedure on a sample that must contain a periodic structure because it diffracts visible light, but on which no structure was visible on the SEM image. In both cases, we obtained clearly periodic patterns that allowed measurements of structural parameters. We also investigated how the irregularly broken surface interfered with the periodic structure to produce additional periodicity. We tested the limits of our methodology with the help of simulated images. © 2014 Wiley Periodicals, Inc.

A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for In-Situ Mars Surface Sample Analysis

NASA Technical Reports Server (NTRS)

Edmunson, J.; Gaskin, J. A.; Jerman, G. A.; Harvey, R. P.; Doloboff, I. J.; Neidholdt, E. L.

2016-01-01

The Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) project, funded by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Research Opportunities in Space and Earth Sciences (ROSES), will build upon previous miniaturized SEM designs and recent advancements in variable pressure SEM's to design and build a SEM to complete analyses of samples on the surface of Mars using the atmosphere as an imaging medium. This project is a collaboration between NASA Marshall Space Flight Center (MSFC), the Jet Propulsion Laboratory (JPL), electron gun and optics manufacturer Applied Physics Technologies, and small vacuum system manufacturer Creare. Dr. Ralph Harvery and environmental SEM (ESEM) inventor Dr. Gerry Danilatos serve as advisors to the team. Variable pressure SEMs allow for fine (nm-scale) resolution imaging and micron-scale chemical study of materials without sample preparation (e.g., carbon or gold coating). Charging of a sample is reduced or eliminated by the gas surrounding the sample. It is this property of ESEMs that make them ideal for locations where sample preparation is not yet feasible, such as the surface of Mars. In addition, the lack of sample preparation needed here will simplify the sample acquisition process and allow caching of the samples for future complementary payload use.

Payload isolation and stabilization by a Suspended Experiment Mount (SEM)

NASA Technical Reports Server (NTRS)

Bailey, Wayne L.; Desanctis, Carmine E.; Nicaise, Placide D.; Schultz, David N.

1992-01-01

Many Space Shuttle and Space Station payloads can benefit from isolation from crew or attitude control system disturbances. Preliminary studies have been performed for a Suspended Experiment Mount (SEM) system that will provide isolation from accelerations and stabilize the viewing direction of a payload. The concept consists of a flexible suspension system and payload-mounted control moment gyros. The suspension system, which is rigidly locked for ascent and descent, isolates the payload from high frequency disturbances. The control moment gyros stabilize the payload orientation. The SEM will be useful for payloads that require a lower-g environment than a manned vehicle can provide, such as materials processing, and for payloads that require stabilization of pointing direction, but not large angle slewing, such as nadir-viewing earth observation or solar viewing payloads.

Recent Advances on In Situ SEM Mechanical and Electrical Characterization of Low-Dimensional Nanomaterials.

PubMed

Jiang, Chenchen; Lu, Haojian; Zhang, Hongti; Shen, Yajing; Lu, Yang

2017-01-01

In the past decades, in situ scanning electron microscopy (SEM) has become a powerful technique for the experimental study of low-dimensional (1D/2D) nanomaterials, since it can provide unprecedented details for individual nanostructures upon mechanical and electrical stimulus and thus uncover the fundamental deformation and failure mechanisms for their device applications. In this overview, we summarized recent developments on in situ SEM-based mechanical and electrical characterization techniques including tensile, compression, bending, and electrical property probing on individual nanostructures, as well as the state-of-the-art electromechanical coupling analysis. In addition, the advantages and disadvantages of in situ SEM tests were also discussed with some possible solutions to address the challenges. Furthermore, critical challenges were also discussed for the development and design of robust in situ SEM characterization platform with higher resolution and wider range of samples. These experimental efforts have offered in-depth understanding on the mechanical and electrical properties of low-dimensional nanomaterial components and given guidelines for their further structural and functional applications.

Recent Advances on In Situ SEM Mechanical and Electrical Characterization of Low-Dimensional Nanomaterials

PubMed Central

Jiang, Chenchen; Lu, Haojian; Zhang, Hongti

2017-01-01

In the past decades, in situ scanning electron microscopy (SEM) has become a powerful technique for the experimental study of low-dimensional (1D/2D) nanomaterials, since it can provide unprecedented details for individual nanostructures upon mechanical and electrical stimulus and thus uncover the fundamental deformation and failure mechanisms for their device applications. In this overview, we summarized recent developments on in situ SEM-based mechanical and electrical characterization techniques including tensile, compression, bending, and electrical property probing on individual nanostructures, as well as the state-of-the-art electromechanical coupling analysis. In addition, the advantages and disadvantages of in situ SEM tests were also discussed with some possible solutions to address the challenges. Furthermore, critical challenges were also discussed for the development and design of robust in situ SEM characterization platform with higher resolution and wider range of samples. These experimental efforts have offered in-depth understanding on the mechanical and electrical properties of low-dimensional nanomaterial components and given guidelines for their further structural and functional applications. PMID:29209445

The advancement of the built environment research through employment of structural equation modeling (SEM)

NASA Astrophysics Data System (ADS)

Wasilah, S.; Fahmyddin, T.

2018-03-01

The employment of structural equation modeling (SEM) in research has taken an increasing attention in among researchers in built environment. There is a gap to understand the attributes, application, and importance of this approach in data analysis in built environment study. This paper intends to provide fundamental comprehension of SEM method in data analysis, unveiling attributes, employment and significance and bestow cases to assess associations amongst variables and constructs. The study uses some main literature to grasp the essence of SEM regarding with built environment research. The better acknowledgment of this analytical tool may assist the researcher in the built environment to analyze data under complex research questions and to test multivariate models in a single study.

Are the evidences of forensic entomology preserved in ethanol suitable for SEM studies?

PubMed

López-Esclapez, Raquel; García, María-Dolores; Arnaldos, María-Isabel; Presa, Juan José; Ubero-Pascal, Nicolás

2014-07-01

In forensic practice, the use of arthropod evidences to estimate the postmortem interval is a very good approach when the elapsed time from death is long, but it requires the correct identification of the specimens. This is a crucial step, not always easy to achieve, in particular when dealing with immature specimens. In this case, scanning electronic microscopy (SEM) can be useful, but the techniques used to preserve specimens in forensic practice are usually different from those used to prepare specimens for SEM studies. To determine whether forensic evidences preserving techniques are also compatible with SEM analysis, we have compared specimens of all the immature stages of Calliphora vicina Robineau-Desvoidy, 1830 (Diptera, Calliphoridae) preserved in 70% ethanol, with others prepared with aldehydic fixative techniques that are more appropriate for SEM studies. At the same time, two drying techniques have also been compared with both fixative techniques, the critical point drying and air-drying following with hexamethyldisilizane treatment (HMDS). Our results indicate that there are not basis against recommending the use of ethanol to preserve forensic entomological evidences and that both drying methods appear to offer good results for second and third instar larvae, although HMDS behaves better with eggs and pupae. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Revisiting the chemical diversity in prostatic calculi: a SEM and FT-IR investigation].

PubMed

Dessombz, A; Méria, P; Bazin, D; Foy, E; Rouzière, S; Weil, R; Daudon, M

2011-12-01

Revisiting the chemical diversity of the crystalline phases of prostatic calculi by means of SEM and FT-IR analysis. A set of 32 prostatic calculi has been studied by FT-IR and SEM. FT-IR analysis has determined the chemical composition of each prostatic calculus and the SEM observation has described the morphology of the calculi surfaces and layers. Infrared analysis revealed that 90.7% of the stones were mainly composed of calcium phosphates. However, several mineral phases previously not reported in prostatic calculi were observed, as brushite or octocalcium phosphate pentahydrate. Prostatic calculi exhibited a diversity of crystalline composition and morphology. As previously reported for urinary calculi, relationships between composition and morphology of prostatic stones and étiopathogenic conditions could be of interest in clinical practice. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Developing 3D SEM in a broad biological context

PubMed Central

Kremer, A; Lippens, S; Bartunkova, S; Asselbergh, B; Blanpain, C; Fendrych, M; Goossens, A; Holt, M; Janssens, S; Krols, M; Larsimont, J-C; Mc Guire, C; Nowack, MK; Saelens, X; Schertel, A; Schepens, B; Slezak, M; Timmerman, V; Theunis, C; Van Brempt, R; Visser, Y; GuÉRin, CJ

2015-01-01

When electron microscopy (EM) was introduced in the 1930s it gave scientists their first look into the nanoworld of cells. Over the last 80 years EM has vastly increased our understanding of the complex cellular structures that underlie the diverse functions that cells need to maintain life. One drawback that has been difficult to overcome was the inherent lack of volume information, mainly due to the limit on the thickness of sections that could be viewed in a transmission electron microscope (TEM). For many years scientists struggled to achieve three-dimensional (3D) EM using serial section reconstructions, TEM tomography, and scanning EM (SEM) techniques such as freeze-fracture. Although each technique yielded some special information, they required a significant amount of time and specialist expertise to obtain even a very small 3D EM dataset. Almost 20 years ago scientists began to exploit SEMs to image blocks of embedded tissues and perform serial sectioning of these tissues inside the SEM chamber. Using first focused ion beams (FIB) and subsequently robotic ultramicrotomes (serial block-face, SBF-SEM) microscopists were able to collect large volumes of 3D EM information at resolutions that could address many important biological questions, and do so in an efficient manner. We present here some examples of 3D EM taken from the many diverse specimens that have been imaged in our core facility. We propose that the next major step forward will be to efficiently correlate functional information obtained using light microscopy (LM) with 3D EM datasets to more completely investigate the important links between cell structures and their functions. Lay Description Life happens in three dimensions. For many years, first light, and then EM struggled to image the smallest parts of cells in 3D. With recent advances in technology and corresponding improvements in computing, scientists can now see the 3D world of the cell at the nanoscale. In this paper we present the

SEM/EDS and optical microscopy analyses of microplastics in ocean trawl and fish guts.

PubMed

Wang, Zhong-Min; Wagner, Jeff; Ghosal, Sutapa; Bedi, Gagandeep; Wall, Stephen

2017-12-15

Microplastic particles from Atlantic and Pacific Ocean trawls, lab-fed fish guts and ocean fish guts have been characterized using optical microscopy and SEM/EDS in terms of size, morphology, and chemistry. We assessed whether these measurements could serve as a rapid screening process for subsequent identification of the likely microplastic candidates by micro-spectroscopy. Optical microscopy enabled morphological classification of the types of particles or fibers present in the sample, as well as the quantification of particle size ranges and fiber lengths. SEM/EDS analysis was used to rule out non-plastic particles and screen the prepared samples for potential microplastic, based on their element signatures and surface characteristics. Chlorinated plastics such as polyvinyl chloride (PVC) could be easily identified with SEM/EDS due to their unique elemental signatures including chlorine, as could mineral species that are falsely identified as plastics by optical microscopy. Particle morphology determined by optical microscopy and SEM suggests the fish ingested particles contained both degradation fragments from larger plastic pieces and also manufactured microplastics. SEM images of microplastic particle surfaces revealed characteristic cracks consistent with environmental exposure, as well as pigment particles consistent with manufactured materials. Most of the microplastic surfaces in the fish guts and ocean trawls were covered with biofilms, radiolarians, and crustaceans. Many of the fish stomachs contained micro-shell pieces which visually resembled microplastics. Copyright © 2017 Elsevier B.V. All rights reserved.

New airtight transfer box for SEM experiments: Application to lithium and sodium metals observation and analyses.

PubMed

Stephant, Nicolas; Grissa, Rabeb; Guillou, Fanch; Bretaudeau, Mickaël; Borjon-Piron, Yann; Guillet, Jacques; Moreau, Philippe

2018-04-18

The surface of some materials reacts very quickly on contact with air, either because it is oxidized or because it gets humidity from the air. For the sake of original surface observation by scanning electron microscopy (SEM), we conceived an airtight transfer box to keep the samples under vacuum from the place of manufacturing to the SEM chamber. This object is designed to fit in all the models of SEM including those provided with an airlock chamber. The design is voluntarily simplified to allow the manufacturing of the object by a standard mechanical workshop. The transfer box can be easily opened by gravity inside the SEM and allows the preservation of the best vacuum inside, before opening. SEM images and energy dispersive spectroscopy (EDX) analyses of metallic lithium and sodium samples are presented prior and after exposure to the air. X-ray Photoelectron Spectroscopy (XPS) analyses of all samples are also discussed in order to investigate the chemical environments of the detected elements. Copyright © 2018 Elsevier Ltd. All rights reserved.

Seasonal AVS-SEM relationship in sediments and potential bioavailability of metals in industrialized estuary, southeastern Brazil.

PubMed

Nizoli, Erico Casare; Luiz-Silva, Wanilson

2012-04-01

In anoxic sediments, as those found in estuaries, the mobility of metals can be controlled by the formation of stable sulfide complexes. The potential bioavailability of a metal can then be predicted on the basis of the acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) criterion. Distributions of AVS and SEM (Hg, Cu, Pb, Cd, Zn, and Ni) along the sediment profiles were determined seasonally for three rivers that constitute the Santos-Cubatão estuarine system (SE Brazil), which is located in one of the most industrialized areas of Latin America. AVS and SEM concentrations varied significantly, from 0.04 to 31.9 μmol g(-1) and 0.086-6.659 μmol g(-1), respectively. The highest AVS levels in sediments were detected in the winter, whereas high SEM values predominated in the summer. Considering SEM-AVS molar differences as a parameter to evaluate potential bioavailability, sediments nearest to the industrial area represent higher risk to biota, especially during the summer. It is due to relatively low AVS values and not necessarily high concentrations of metals.

The effect of SEM imaging on the Ar/Ar system in feldspars

NASA Astrophysics Data System (ADS)

Flude, S.; Sherlock, S.; Lee, M.; Kelley, S. P.

2010-12-01

Complex microtextures form in K-feldspar crystals as they cool and are affected by deuteric alteration. This complex structure is the cause of variable closure temperatures for Ar-Ar, a phenomenon which has been utilized in multi domain diffusion (MDD) modelling to recover thermal histories [1]. However, there has been substantial controversy regarding the precise interaction between feldspar microtextures and Ar-diffusion [2,3]. A number of studies have addressed this issue using coupled SEM imaging and Ar/Ar UV laser ablation microprobe (UV-LAMP) analysis on the same sample, to enable direct comparison of microtextures with Ar/Ar age data [4]. Here we have tested the idea that SEM work may affect Ar/Ar ages, leading to inaccurate results in subsequent Ar/Ar analyses. Three splits of alkali feldspar from the Dartmoor Granite in SW England were selected for Ar/Ar UV-LAMP analysis. Split 1 (“control”) was prepared as a polished thick section for Ar/Ar analysis. Split 2 (“SEM”) was prepared as a polished thick section, was chemically-mechanically polished with colloidal silica and underwent SEM imaging (uncoated) and focussed ion beam (FIB) milling (gold coated); electron beam damage in the SEM was maximised by leaving the sample at high magnification for eight minutes. Split 3 (“Etch”) is a cleavage fragment that was etched with HF vapour and underwent low to moderate magnification SEM imaging. The control split gave a range of laser-spot ages consistent with the expected cooling age of the granite and high yields of radiogenic 40Ar* (>90%). The area of the “SEM” split that experienced significant electron beam damage gave younger than expected ages and 40Ar* yields as low as 57%. These are interpreted as a combination of implantation of atmospheric Ar and local redistribution of K within the sample. The area of “SEM” that underwent FIB milling gave ages and 40Ar* yields comparable to the control split, suggesting that the Au-coat minimises FIB

Precise and economic FIB/SEM for CLEM: with 2 nm voxels through mitosis.

PubMed

Luckner, Manja; Wanner, Gerhard

2018-05-23

A portfolio is presented documenting economic, high-resolution correlative focused ion beam scanning electron microscopy (FIB/SEM) in routine, comprising: (i) the use of custom-labeled slides and coverslips, (ii) embedding of cells in thin, or ultra-thin resin layers for correlative light and electron microscopy (CLEM) and (iii) the claim to reach the highest resolution possible with FIB/SEM in xyz. Regions of interest (ROIs) defined in light microscope (LM), can be relocated quickly and precisely in SEM. As proof of principle, HeLa cells were investigated in 3D context at all stages of the cell cycle, documenting ultrastructural changes during mitosis: nuclear envelope breakdown and reassembly, Golgi degradation and reconstitution and the formation of the midzone and midbody.

FIB-SEM tomography of human skin telocytes and their extracellular vesicles

PubMed Central

Cretoiu, Dragos; Gherghiceanu, Mihaela; Hummel, Eric; Zimmermann, Hans; Simionescu, Olga; Popescu, Laurentiu M

2015-01-01

We have shown in 2012 the existence of telocytes (TCs) in human dermis. TCs were described by transmission electron microscopy (TEM) as interstitial cells located in non-epithelial spaces (stroma) of many organs (see www.telocytes.com). TCs have very long prolongations (tens to hundreds micrometers) named Telopodes (Tps). These Tps have a special conformation with dilated portions named podoms (containing mitochondria, endoplasmic reticulum and caveolae) and very thin segments (below resolving power of light microscopy), called podomers. To show the real 3D architecture of TC network, we used the most advanced available electron microscope technology: focused ion beam scanning electron microscopy (FIB-SEM) tomography. Generally, 3D reconstruction of dermal TCs by FIB-SEM tomography revealed the existence of Tps with various conformations: (i) long, flattened irregular veils (ribbon-like segments) with knobs, corresponding to podoms, and (ii) tubular structures (podomers) with uneven calibre because of irregular dilations (knobs) – the podoms. FIB-SEM tomography also showed numerous extracellular vesicles (diameter 438.6 ± 149.1 nm, n = 30) released by a human dermal TC. Our data might be useful for understanding the role(s) of TCs in intercellular signalling and communication, as well as for comprehension of pathologies like scleroderma, multiple sclerosis, psoriasis, etc. PMID:25823591

Surface ultrastructural (SEM) characteristics of oropharyngeal cavity of house sparrow (Passer domesticus).

PubMed

Abumandour, Mohamed M A

2018-06-01

The focus of the present study is to provide a full morphological description of the oropharyngeal cavity of the house sparrow. The head of six birds was prepared for gross examination and by stereo and electron microscopy. The bifid lingual apex has multiple long, rostrally directed needle-like processes. The lateral border of the apex carries rostromedially directed needle-like processes. The dorsal lingual surface of the apex and body carries numerous caudomedially directed filiform papillae and many orifices of lingual salivary glands. The lingual body is divided into two parts: rostral and caudal. The caudal part is divided into two laterally elevated regions by a median groove, while the rostral part is bounded laterally by a rostrodorsally directed papillary row, which on SEM is formed from two rows. On SEM, the lingual root has many orifices of posterior salivary glands. The pharyngeal papillary row is located at the caudal border of the laryngeal mound, but this single papillary row is formed from two rows at SEM magnification. The laryngeal cleft continues caudally as a laryngeal fissure bounded by two longitudinal rows of caudally directed papillae; at high SEM magnification, this fissure is divided into two halves by a median ridge which carries caudally directed papillae on its posterior part. The choanal cleft proceeds rostrally by the median tubercle. There are a small number of orifices of palatine salivary glands. The morphological characters of the oropharyngeal cavity of the sparrow confirm its adaptation to surrounding environmental conditions and available food particles.

3D reconstruction of SEM images by use of optical photogrammetry software.

PubMed

Eulitz, Mona; Reiss, Gebhard

2015-08-01

Reconstruction of the three-dimensional (3D) surface of an object to be examined is widely used for structure analysis in science and many biological questions require information about their true 3D structure. For Scanning Electron Microscopy (SEM) there has been no efficient non-destructive solution for reconstruction of the surface morphology to date. The well-known method of recording stereo pair images generates a 3D stereoscope reconstruction of a section, but not of the complete sample surface. We present a simple and non-destructive method of 3D surface reconstruction from SEM samples based on the principles of optical close range photogrammetry. In optical close range photogrammetry a series of overlapping photos is used to generate a 3D model of the surface of an object. We adapted this method to the special SEM requirements. Instead of moving a detector around the object, the object itself was rotated. A series of overlapping photos was stitched and converted into a 3D model using the software commonly used for optical photogrammetry. A rabbit kidney glomerulus was used to demonstrate the workflow of this adaption. The reconstruction produced a realistic and high-resolution 3D mesh model of the glomerular surface. The study showed that SEM micrographs are suitable for 3D reconstruction by optical photogrammetry. This new approach is a simple and useful method of 3D surface reconstruction and suitable for various applications in research and teaching. Copyright © 2015 Elsevier Inc. All rights reserved.

Correlation of two-photon in vivo imaging and FIB/SEM microscopy

PubMed Central

Blazquez-Llorca, L; Hummel, E; Zimmerman, H; Zou, C; Burgold, S; Rietdorf, J; Herms, J

2015-01-01

Advances in the understanding of brain functions are closely linked to the technical developments in microscopy. In this study, we describe a correlative microscopy technique that offers a possibility of combining two-photon in vivo imaging with focus ion beam/scanning electron microscope (FIB/SEM) techniques. Long-term two-photon in vivo imaging allows the visualization of functional interactions within the brain of a living organism over the time, and therefore, is emerging as a new tool for studying the dynamics of neurodegenerative diseases, such as Alzheimer’s disease. However, light microscopy has important limitations in revealing alterations occurring at the synaptic level and when this is required, electron microscopy is mandatory. FIB/SEM microscopy is a novel tool for three-dimensional high-resolution reconstructions, since it acquires automated serial images at ultrastructural level. Using FIB/SEM imaging, we observed, at 10 nm isotropic resolution, the same dendrites that were imaged in vivo over 9 days. Thus, we analyzed their ultrastructure and monitored the dynamics of the neuropil around them. We found that stable spines (present during the 9 days of imaging) formed typical asymmetric contacts with axons, whereas transient spines (present only during one day of imaging) did not form a synaptic contact. Our data suggest that the morphological classification that was assigned to a dendritic spine according to the in vivo images did not fit with its ultrastructural morphology. The correlative technique described herein is likely to open opportunities for unravelling the earlier unrecognized complexity of the nervous system. Lay Description Neuroscience and the understanding of brain functions are closely linked to the technical advances in microscopy. In this study we performed a correlative microscopy technique that offers the possibility to combine 2 photon in vivo imaging and FIB/SEM microscopy. Long term 2 photon in vivo imaging allows the

Classification and printability of EUV mask defects from SEM images

NASA Astrophysics Data System (ADS)

Cho, Wonil; Price, Daniel; Morgan, Paul A.; Rost, Daniel; Satake, Masaki; Tolani, Vikram L.

2017-10-01

Classification and Printability of EUV Mask Defects from SEM images EUV lithography is starting to show more promise for patterning some critical layers at 5nm technology node and beyond. However, there still are many key technical obstacles to overcome before bringing EUV Lithography into high volume manufacturing (HVM). One of the greatest obstacles is manufacturing defect-free masks. For pattern defect inspections in the mask-shop, cutting-edge 193nm optical inspection tools have been used so far due to lacking any e-beam mask inspection (EBMI) or EUV actinic pattern inspection (API) tools. The main issue with current 193nm inspection tools is the limited resolution for mask dimensions targeted for EUV patterning. The theoretical resolution limit for 193nm mask inspection tools is about 60nm HP on masks, which means that main feature sizes on EUV masks will be well beyond the practical resolution of 193nm inspection tools. Nevertheless, 193nm inspection tools with various illumination conditions that maximize defect sensitivity and/or main-pattern modulation are being explored for initial EUV defect detection. Due to the generally low signal-to-noise in the 193nm inspection imaging at EUV patterning dimensions, these inspections often result in hundreds and thousands of defects which then need to be accurately reviewed and dispositioned. Manually reviewing each defect is difficult due to poor resolution. In addition, the lack of a reliable aerial dispositioning system makes it very challenging to disposition for printability. In this paper, we present the use of SEM images of EUV masks for higher resolution review and disposition of defects. In this approach, most of the defects detected by the 193nm inspection tools are first imaged on a mask SEM tool. These images together with the corresponding post-OPC design clips are provided to KLA-Tencor's Reticle Decision Center (RDC) platform which provides ADC (Automated Defect Classification) and S2A (SEM

Design of a solar collector system formed by a Fresnel lens and a CEC coupled to plastic fibers

NASA Astrophysics Data System (ADS)

Viera-González, Perla M.; Sánchez-Guerrero, Guillermo E.; Ceballos-Herrera, Daniel E.; Selvas-Aguilar, Romeo

2015-08-01

Among the main challenges for systems based in solar concentrators and plastic optical fibers (POF) the accuracy needed for the solar tracking is founded. One approach to overcome these requirements is increasing acceptance angle of the components, usually by secondary optical elements (SOE), however this technique is effective for photovoltaic applications but it has not been analyzed for systems coupled to POFs for indoor illumination. On this subject, it is presented a numerical analysis of a solar collector assembled by a Fresnel lens as primary optical element (POE) combined with a compound elliptical concentrator (CEC) coupled to POF in order to compare its performance under incidence angle direction and also to show a trade-off analysis for two different Fresnel lens shapes, imaging and nonimaging, used in the collector system. The description of the Fresnel lenses and its designs are included, in addition to the focal areas with space and angular distribution profiles considering the optimal alignment with the source and maximum permissible incident angle for each case. For both systems the coupling between the optical components is analyzed and the total performance is calculated, having as result its comparison for indoor illumination. In both cases, the systems have better performance increasing the final output power, but the angular tolerance only was improved for the system with nonimaging concentrator that had an efficiency over 80% with acceptance angles 𝜃𝑖 ≤ 2° and, the system integrated by the imaging lens, presented an efficiency ratio over 75% for acceptance angles 𝜃𝑖 ≤ 0.7°.

Does your SEM really tell the truth?--How would you know? Part 1.

PubMed

Postek, Michael T; Vladár, András E

2013-01-01

The scanning electron microscope (SEM) has gone through a tremendous evolution to become a critical tool for many and diverse scientific and industrial applications. The high resolution of the SEM is especially suited for both qualitative and quantitative applications especially for nanotechnology and nanomanufacturing. Quantitatively, measurement, or metrology is one of the main uses. It is likely that one of the first questions asked before even the first scanning electron micrograph was ever recorded was: "… how big is that?" The quality of that answer has improved a great deal over the past few years especially since today these instruments are being used as a primary measurement tool on semiconductor processing lines to monitor the manufacturing processes. The well-articulated needs of semiconductor production prompted a rapid evolution of the instrument and its capabilities. Over the past 20 years or so, instrument manufacturers, through substantial semiconductor industry investment of research and development (R&D) money, have vastly improved the performance of these instruments. All users have benefited from this investment, especially where quantitative measurements with an SEM are concerned. But, how good are these data? This article discusses some of the most important aspects and larger issues associated with imaging and measurements with the SEM that every user should know, and understand before any critical quantitative work is attempted. © Wiley Periodicals, Inc.

Robust surface reconstruction by design-guided SEM photometric stereo

NASA Astrophysics Data System (ADS)

Miyamoto, Atsushi; Matsuse, Hiroki; Koutaki, Gou

2017-04-01

We present a novel approach that addresses the blind reconstruction problem in scanning electron microscope (SEM) photometric stereo for complicated semiconductor patterns to be measured. In our previous work, we developed a bootstrapping de-shadowing and self-calibration (BDS) method, which automatically calibrates the parameter of the gradient measurement formulas and resolves shadowing errors for estimating an accurate three-dimensional (3D) shape and underlying shadowless images. Experimental results on 3D surface reconstruction demonstrated the significance of the BDS method for simple shapes, such as an isolated line pattern. However, we found that complicated shapes, such as line-and-space (L&S) and multilayered patterns, produce deformed and inaccurate measurement results. This problem is due to brightness fluctuations in the SEM images, which are mainly caused by the energy fluctuations of the primary electron beam, variations in the electronic expanse inside a specimen, and electrical charging of specimens. Despite these being essential difficulties encountered in SEM photometric stereo, it is difficult to model accurately all the complicated physical phenomena of electronic behavior. We improved the robustness of the surface reconstruction in order to deal with these practical difficulties with complicated shapes. Here, design data are useful clues as to the pattern layout and layer information of integrated semiconductors. We used the design data as a guide of the measured shape and incorporated a geometrical constraint term to evaluate the difference between the measured and designed shapes into the objective function of the BDS method. Because the true shape does not necessarily correspond to the designed one, we use an iterative scheme to develop proper guide patterns and a 3D surface that provides both a less distorted and more accurate 3D shape after convergence. Extensive experiments on real image data demonstrate the robustness and effectiveness

Optimization of SEM-EDS to determine the C–A–S–H composition in matured cement paste samples

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

Rossen, J.E., E-mail: john.rossen@alumni.epfl.ch

Microanalysis of characteristic X-rays in the SEM is a powerful method to assess the chemical composition of phases in cement pastes, in particular the calcium silicate hydrate containing aluminium (C–A–S–H). Nevertheless, many variables may influence the results obtained, due mainly to the intimate mixing of C–A–S–H with other hydrate phases and the susceptibility of this phase to damage by the electron beam. In this study the effect of various acquisition parameters was examined, along with methods to determine an “average” C–A–S–H composition. The results acquired in the SEM were compared with the analysis of the same samples in the TEM,more » where phases can be analyzed without intermixing. A simple method was used to obtain compositions from SEM based analysis that are very close to those which can be obtained in the TEM. - Highlights: •The intermixing of phases is the limiting factor in the analysis of C–A–S–H composition by SEM-EDS •Guidelines to limit beam damage and properly analyze C–A–S–H composition by SEM-EDS are given •SEM-EDS and TEM-EDS give similar results when proper data treatment is made.« less

Signal-to-noise ratio estimation on SEM images using cubic spline interpolation with Savitzky-Golay smoothing.

PubMed

Sim, K S; Kiani, M A; Nia, M E; Tso, C P

2014-01-01

A new technique based on cubic spline interpolation with Savitzky-Golay noise reduction filtering is designed to estimate signal-to-noise ratio of scanning electron microscopy (SEM) images. This approach is found to present better result when compared with two existing techniques: nearest neighbourhood and first-order interpolation. When applied to evaluate the quality of SEM images, noise can be eliminated efficiently with optimal choice of scan rate from real-time SEM images, without generating corruption or increasing scanning time. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

Strategic Enrolment Management (SEM) in Self-Financed Higher Education of Hong Kong: Evaluation and Measurement

ERIC Educational Resources Information Center

Ng, Peggy; Galbraith, Craig

2016-01-01

The purpose of this study is to examine how the dimensions of strategic enrolment management (SEM) tie to the success metrics in the area of enrolment, retention and graduation from senior and programme management perspectives of a self-financed institution in Hong Kong. The literature on SEM has demonstrated that managing enrolment is a global…

SEM Imaging for Observation of Morphological Changes in Anaemic Human Blood Cell

NASA Astrophysics Data System (ADS)

Datta, Triparna; Roychoudhury, Uttam

Scanning Electron Microscopy (SEM) is utilized to elucidate the morphological changes in anaemic human red blood cells. Haemoglobin concentration in human blood is in the range of 11.5-13.5 g/dl in healthy adults. Haemoglobin concentration in anaemic red blood is below the lower limit of normal range. Sometimes, the nature of the abnormal shape of the blood cell determines the cause of anaemia. Normally, there occurs a variation in the diameter of the red blood cell (RBC) for different types of anaemia. Increased variation of size in blood cell is termed anisocytosis (a type of anaemia) (Mohan H, Text book of pathology, New Delhi). In case of anisocytosis, diameter of cells larger than normal cell is observed. The classification of anaemia by the size of blood cell is logical, i.e. common morphological abnormality of human blood cell (Davidson's principle and practice of medicine, Publisher Churchill Livingstone, London). Cells are studied under ZEISS SEM with different magnification and applied potential of kV range. Thus the diameters of RBCs in SEM have been compared with RBCs photographed with light microscope. Anaemic cells are observed overlapped with each other with increasing diameter.

FIB-SEM tomography of human skin telocytes and their extracellular vesicles.

PubMed

Cretoiu, Dragos; Gherghiceanu, Mihaela; Hummel, Eric; Zimmermann, Hans; Simionescu, Olga; Popescu, Laurentiu M

2015-04-01

We have shown in 2012 the existence of telocytes (TCs) in human dermis. TCs were described by transmission electron microscopy (TEM) as interstitial cells located in non-epithelial spaces (stroma) of many organs (see www.telocytes.com). TCs have very long prolongations (tens to hundreds micrometers) named Telopodes (Tps). These Tps have a special conformation with dilated portions named podoms (containing mitochondria, endoplasmic reticulum and caveolae) and very thin segments (below resolving power of light microscopy), called podomers. To show the real 3D architecture of TC network, we used the most advanced available electron microscope technology: focused ion beam scanning electron microscopy (FIB-SEM) tomography. Generally, 3D reconstruction of dermal TCs by FIB-SEM tomography revealed the existence of Tps with various conformations: (i) long, flattened irregular veils (ribbon-like segments) with knobs, corresponding to podoms, and (ii) tubular structures (podomers) with uneven calibre because of irregular dilations (knobs) - the podoms. FIB-SEM tomography also showed numerous extracellular vesicles (diameter 438.6 ± 149.1 nm, n = 30) released by a human dermal TC. Our data might be useful for understanding the role(s) of TCs in intercellular signalling and communication, as well as for comprehension of pathologies like scleroderma, multiple sclerosis, psoriasis, etc. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Does your SEM really tell the truth? How would you know? Part 2.

PubMed

Postek, Michael T; Vladár, András E; Purushotham, Kavuri P

2014-01-01

The scanning electron microscope (SEM) has gone through a tremendous evolution to become indispensable for many and diverse scientific and industrial applications. The improvements have significantly enriched and augmented the overall SEM performance and have made the instrument far easier to operate. But, the ease of operation also might lead, through operator complacency, to poor results. In addition, the user friendliness has seemingly reduced the need for thorough operator training for using these complex instruments. One might then conclude that the SEM is just a very expensive digital camera or another peripheral device for a computer. Hence, a person using the instrument may be lulled into thinking that all of the potential pitfalls have been eliminated and they believe everything they see on the micrograph is always correct. But, this may not be the case. An earlier paper (Part 1), discussed some of the potential issues related to signal generation in the SEM, instrument calibration, electron beam interactions and the need for physics-based modeling to understand the actual image formation mechanisms. All these were summed together in a discussion of how these issues effect measurements made with the instrument. This second paper discusses another major issue confronting the microscopist: electron-beam-induced specimen contamination. Over the years, NIST has done a great deal of research into the issue of sample contamination and its removal and elimination and some of this work is reviewed and discussed here. © 2013 Wiley Periodicals, Inc.

Information or resolution: Which is required from an SEM to study bulk inorganic materials?: Evaluate SEMs’ practical performance

DOE PAGES

Xing, Q.

2016-07-11

Significant technological advances in scanning electron microscopy (SEM) have been achieved over the past years. Different SEMs can have significant differences in functionality and performance. This work presents the perspectives on selecting an SEM for research on bulk inorganic materials. Understanding materials demands quantitative composition and orientation information, and informative and interpretable images that reveal subtle differences in chemistry, orientation/structure, topography, and electronic structure. The capability to yield informative and interpretable images with high signal-to-noise ratios and spatial resolutions is an overall result of the SEM system as a whole, from the electron optical column to the detection system. Themore » electron optical column determines probe performance. The roles of the detection system are to capture, filter or discriminate, and convert signal electrons to imaging information. The capability to control practical operating parameters including electron probe size and current, acceleration voltage or landing voltage, working distance, detector selection, and signal filtration is inherently determined by the SEM itself. As a platform for various accessories, e.g. an energydispersive spectrometer and an electron backscatter diffraction detector, the properties of the electron optical column, specimen chamber, and stage greatly affect the performance of accessories. Ease-of-use and ease-of-maintenance are of practical importance. It is practically important to select appropriate test specimens, design suitable imaging conditions, and analyze the specimen chamber geometry and dimensions to assess the overall functionality and performance of an SEM. Finally, for an SEM that is controlled/operated with a computer, the stable software and user-friendly interface significantly affect the usability of the SEM.« less

Information or resolution: Which is required from an SEM to study bulk inorganic materials?: Evaluate SEMs’ practical performance

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

Xing, Q.

Significant technological advances in scanning electron microscopy (SEM) have been achieved over the past years. Different SEMs can have significant differences in functionality and performance. This work presents the perspectives on selecting an SEM for research on bulk inorganic materials. Understanding materials demands quantitative composition and orientation information, and informative and interpretable images that reveal subtle differences in chemistry, orientation/structure, topography, and electronic structure. The capability to yield informative and interpretable images with high signal-to-noise ratios and spatial resolutions is an overall result of the SEM system as a whole, from the electron optical column to the detection system. Themore » electron optical column determines probe performance. The roles of the detection system are to capture, filter or discriminate, and convert signal electrons to imaging information. The capability to control practical operating parameters including electron probe size and current, acceleration voltage or landing voltage, working distance, detector selection, and signal filtration is inherently determined by the SEM itself. As a platform for various accessories, e.g. an energydispersive spectrometer and an electron backscatter diffraction detector, the properties of the electron optical column, specimen chamber, and stage greatly affect the performance of accessories. Ease-of-use and ease-of-maintenance are of practical importance. It is practically important to select appropriate test specimens, design suitable imaging conditions, and analyze the specimen chamber geometry and dimensions to assess the overall functionality and performance of an SEM. Finally, for an SEM that is controlled/operated with a computer, the stable software and user-friendly interface significantly affect the usability of the SEM.« less

Study of SEM preparation artefacts with correlative microscopy: Cell shrinkage of adherent cells by HMDS-drying.

PubMed

Katsen-Globa, Alisa; Puetz, Norbert; Gepp, Michael M; Neubauer, Julia C; Zimmermann, Heiko

2016-11-01

One of the often reported artefacts during cell preparation to scanning electron microscopy (SEM) is the shrinkage of cellular objects, that mostly occurs at a certain time-dependent stage of cell drying. Various methods of drying for SEM, such as critical point drying, freeze-drying, as well as hexamethyldisilazane (HMDS)-drying, were usually used. The latter becomes popular since it is a low cost and fast method. However, the correlation of drying duration and real shrinkage of objects was not investigated yet. In this paper, cell shrinkage at each stage of preparation for SEM was studied. We introduce a shrinkage coefficient using correlative light microscopy (LM) and SEM of the same human mesenchymal stem cells (hMSCs). The influence of HMDS-drying duration on the cell shrinkage is shown: the longer drying duration, the more shrinkage is observed. Furthermore, it was demonstrated that cell shrinkage is inversely proportional to cultivation time: the longer cultivation time, the more cell spreading area and the less cell shrinkage. Our results can be applicable for an exact SEM quantification of cell size and determination of cell spreading area in engineering of artificial cellular environments using biomaterials. SCANNING 38:625-633, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

FIB–SEM tomography of 4th generation PWA 1497 superalloy

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

Ziętara, Maciej, E-mail: zietara@agh.edu.pl; Kruk, Adam, E-mail: kruczek@agh.edu.pl; Gruszczyński, Adam, E-mail: gruszcz@agh.edu.pl

2014-01-15

The effect of creep deformation on the microstructure of the PWA 1497 single crystal Ni-base superalloy developed for turbine blade applications was investigated. The aim of the present study was to characterize quantitatively a superalloy microstructure and subsequent development of rafted γ′ precipitates in the PWA 1497 during creep deformation at 982 °C and 248 MPa up to rupture. The PWA1497 microstructure was characterized by scanning electron microscopy and FIB–SEM electron tomography. The 3D reconstruction of the PWA1497 microstructure is presented and discussed. - Highlights: • The microstructure of PWA1497 superalloy was examined using FIB–SEM tomography. • In case ofmore » modern single crystal superalloys, measurements of A{sub A} are adequate for V{sub V}. • During creep the γ channel width increases from 65 to 193 nm for ruptured specimen. • Tomography is a useful technique for quantitative studies of material microstructure.« less

In-situ thermal cycling in SEM of a graphite-aluminum composite

NASA Technical Reports Server (NTRS)

Cheong, Y. M.; Marcus, H. L.

1987-01-01

In situ SEM observations of a graphite-aluminum composite (unidirectional P100 graphite-fiber-reinforced 6061 aluminum MMC plates) were used to measure displacements within the graphite fiber relative to the interface between the graphite fiber and the aluminum matrix during thermal cycling. Specimens were thermally cycled from room temperature to 300 C or 500 C in a SEM chamber and then cooled to room temperature. The obtained shear strains within the fiber were then related to anomalous values of measured residual stresses and to the impact on the composite coefficient of expansion and potential damage under thermal fatigue loading. The shear mechanism was proposed as a source of temperature limits on the low coefficient of expansion of these composites, as well as a potential source of thermal fatigue degradation.

AxiSEM3D: broadband seismic wavefields in 3-D aspherical Earth models

NASA Astrophysics Data System (ADS)

Leng, K.; Nissen-Meyer, T.; Zad, K. H.; van Driel, M.; Al-Attar, D.

2017-12-01

Seismology is the primary tool for data-informed inference of Earth structure and dynamics. Simulating seismic wave propagation at a global scale is fundamental to seismology, but remains as one of most challenging problems in scientific computing, because of both the multiscale nature of Earth's interior and the observable frequency band of seismic data. We present a novel numerical method to simulate global seismic wave propagation in realistic 3-D Earth models. Our method, named AxiSEM3D, is a hybrid of spectral element method and pseudospectral method. It reduces the azimuthal dimension of wavefields by means of a global Fourier series parameterization, of which the number of terms can be locally adapted to the inherent azimuthal smoothness of the wavefields. AxiSEM3D allows not only for material heterogeneities, such as velocity, density, anisotropy and attenuation, but also for finite undulations on radial discontinuities, both solid-solid and solid-fluid, and thereby a variety of aspherical Earth features such as ellipticity, topography, variable crustal thickness, and core-mantle boundary topography. Such interface undulations are equivalently interpreted as material perturbations of the contiguous media, based on the "particle relabelling transformation". Efficiency comparisons show that AxiSEM3D can be 1 to 3 orders of magnitude faster than conventional 3-D methods, with the speedup increasing with simulation frequency and decreasing with model complexity, but for all realistic structures the speedup remains at least one order of magnitude. The observable frequency range of global seismic data (up to 1 Hz) has been covered for wavefield modelling upon a 3-D Earth model with reasonable computing resources. We show an application of surface wave modelling within a state-of-the-art global crustal model (Crust1.0), with the synthetics compared to real data. The high-performance C++ code is released at github.com/AxiSEM3D/AxiSEM3D.

Attempt of correlative observation of morphological synaptic connectivity by combining confocal laser-scanning microscope and FIB-SEM for immunohistochemical staining technique.

PubMed

Sonomura, Takahiro; Furuta, Takahiro; Nakatani, Ikuko; Yamamoto, Yo; Honma, Satoru; Kaneko, Takeshi

2014-11-01

Ten years have passed since a serial block-face scanning electron microscopy (SBF-SEM) method was developed [1]. In this innovative method, samples were automatically sectioned with an ultramicrotome placed inside a scanning electron microscope column, and the block surfaces were imaged one after another by SEM to capture back-scattered electrons. The contrast-inverted images obtained by the SBF-SEM were very similar to those acquired using conventional TEM. SFB-SEM has made easy to acquire image stacks of the transmission electron microscopy (TEM) in the mesoscale, which is taken with the confocal laser-scanning microcopy(CF-LSM).Furthermore, serial-section SEM has been combined with the focused ion beam (FIB) milling method [2]. FIB-incorporated SEM (FIB-SEM) has enabled the acquisition of three-dimensional images with a higher z-axis resolution com- pared to ultramicrotome-equipped SEM.We tried immunocytochemistry for FIB-SEM and correlated this immunoreactivity with that in CF-LSM. Dendrites of neurons in the rat neostriatum were visualized using a recombinant viral vector. Moreover, the thalamostriatal afferent terminals were immunolabeled with Cy5 fluorescence for vesicular glutamate transporter 2 (VGluT2). After detection of the sites of terminals apposed to the dendrites by using CF-LSM, GFP and VGluT2 immunoreactivities were further developed for EM by using immunogold/silver enhancement and immunoperoxidase/diaminobenzidine (DAB) methods, respectively.We showed that conventional immuno-cytochemical staining for TEM was applicable to FIB-SEM. Furthermore, several synaptic contacts, which were thought to exist on the basis of CF-LSM findings, were confirmed with FIB-SEM, revealing the usefulness of the combined method of CF-LSM and FIB-SEM. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The Capabilities and Applications of FY-3A/B SEM on Monitoring Space Weather Events

NASA Astrophysics Data System (ADS)

Huang, C.; Li, J.; Yu, T.; Xue, B.; Wang, C.; Zhang, X.; Cao, G.; Liu, D.; Tang, W.

2012-12-01

The Space Environment Monitor (SEM), on board the Chinese meteorological satellites, FengYun-3A/B has the abilities to measure proton flux in 3-300 Mev energy range and electron flux in 0.15-5.7 Mev energy range. SEM can also detect the heavy ion compositions, satellite surface potential, the radiation dose in sensors, and the single events. The space environment information derived from SEM can be utilized for satellite security designs, scientific studies, development of radiation belt models, and space weather monitoring and disaster warning. In this study, the SEM's instrument characteristics are introduced and the post-launch calibration algorithm is presented. The applications in monitoring space weather events and the service for manned spaceflights are also demonstrated.; The protons with particle energy over 10 Mev are called "killer particles". These particles may damage the satellite and cause disruption of satellite's system. The protons flux of 10 M-26 Mev energy band reached 5000 in the SPE caused by a solar flare with CME during the period of 2012.01.23 to 2012.01.27 as shown in the figure. THE COMPARISONS OF HEAVY IONS (2010.11.11-2010.12.15)t;

High incorrect use of the standard error of the mean (SEM) in original articles in three cardiovascular journals evaluated for 2012.

PubMed

Wullschleger, Marcel; Aghlmandi, Soheila; Egger, Marcel; Zwahlen, Marcel

2014-01-01

In biomedical journals authors sometimes use the standard error of the mean (SEM) for data description, which has been called inappropriate or incorrect. To assess the frequency of incorrect use of SEM in articles in three selected cardiovascular journals. All original journal articles published in 2012 in Cardiovascular Research, Circulation: Heart Failure and Circulation Research were assessed by two assessors for inappropriate use of SEM when providing descriptive information of empirical data. We also assessed whether the authors state in the methods section that the SEM will be used for data description. Of 441 articles included in this survey, 64% (282 articles) contained at least one instance of incorrect use of the SEM, with two journals having a prevalence above 70% and "Circulation: Heart Failure" having the lowest value (27%). In 81% of articles with incorrect use of SEM, the authors had explicitly stated that they use the SEM for data description and in 89% SEM bars were also used instead of 95% confidence intervals. Basic science studies had a 7.4-fold higher level of inappropriate SEM use (74%) than clinical studies (10%). The selection of the three cardiovascular journals was based on a subjective initial impression of observing inappropriate SEM use. The observed results are not representative for all cardiovascular journals. In three selected cardiovascular journals we found a high level of inappropriate SEM use and explicit methods statements to use it for data description, especially in basic science studies. To improve on this situation, these and other journals should provide clear instructions to authors on how to report descriptive information of empirical data.

Quantifying Golgi structure using EM: combining volume-SEM and stereology for higher throughput.

PubMed

Ferguson, Sophie; Steyer, Anna M; Mayhew, Terry M; Schwab, Yannick; Lucocq, John Milton

2017-06-01

Investigating organelles such as the Golgi complex depends increasingly on high-throughput quantitative morphological analyses from multiple experimental or genetic conditions. Light microscopy (LM) has been an effective tool for screening but fails to reveal fine details of Golgi structures such as vesicles, tubules and cisternae. Electron microscopy (EM) has sufficient resolution but traditional transmission EM (TEM) methods are slow and inefficient. Newer volume scanning EM (volume-SEM) methods now have the potential to speed up 3D analysis by automated sectioning and imaging. However, they produce large arrays of sections and/or images, which require labour-intensive 3D reconstruction for quantitation on limited cell numbers. Here, we show that the information storage, digital waste and workload involved in using volume-SEM can be reduced substantially using sampling-based stereology. Using the Golgi as an example, we describe how Golgi populations can be sensed quantitatively using single random slices and how accurate quantitative structural data on Golgi organelles of individual cells can be obtained using only 5-10 sections/images taken from a volume-SEM series (thereby sensing population parameters and cell-cell variability). The approach will be useful in techniques such as correlative LM and EM (CLEM) where small samples of cells are treated and where there may be variable responses. For Golgi study, we outline a series of stereological estimators that are suited to these analyses and suggest workflows, which have the potential to enhance the speed and relevance of data acquisition in volume-SEM.

Three-dimensional imaging of adherent cells using FIB/SEM and STEM.

PubMed

Villinger, Clarissa; Schauflinger, Martin; Gregorius, Heiko; Kranz, Christine; Höhn, Katharina; Nafeey, Soufi; Walther, Paul

2014-01-01

In this chapter we describe three different approaches for three-dimensional imaging of electron microscopic samples: serial sectioning transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) tomography, and focused ion beam/scanning electron microscopy (FIB/SEM) tomography. With these methods, relatively large volumes of resin-embedded biological structures can be analyzed at resolutions of a few nm within a reasonable expenditure of time. The traditional method is serial sectioning and imaging the same area in all sections. Another method is TEM tomography that involves tilting a section in the electron beam and then reconstruction of the volume by back projection of the images. When the scanning transmission (STEM) mode is used, thicker sections (up to 1 μm) can be analyzed. The third approach presented here is focused ion beam/scanning electron microscopy (FIB/SEM) tomography, in which a sample is repeatedly milled with a focused ion beam (FIB) and each newly produced block face is imaged with the scanning electron microscope (SEM). This process can be repeated ad libitum in arbitrary small increments allowing 3D analysis of relatively large volumes such as eukaryotic cells. We show that resolution of this approach is considerably improved when the secondary electron signal is used. However, the most important prerequisite for three-dimensional imaging is good specimen preparation. For all three imaging methods, cryo-fixed (high-pressure frozen) and freeze-substituted samples have been used.

30 CFR 250.1917 - What criteria for pre-startup review must be in my SEMS program?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 2 2011-07-01 2011-07-01 false What criteria for pre-startup review must be in... pre-startup review must be in my SEMS program? Your SEMS program must require that the commissioning process include a pre-startup safety and environmental review for new and significantly modified...

COMPARISON OF PROLIFERATIVE CAPACITY OF GENETICALLY-ENGINEERED PIG AND HUMAN CORNEAL ENDOTHELIAL CELLS

PubMed Central

Fujita, Minoru; Mehra, Ruhina; Lee, Seung Eun; Roh, Danny S.; Long, Cassandra; Funderburgh, James L.; Ayares, David L.; Cooper, David K. C.; Hara, Hidetaka

2013-01-01

Purpose The possibility of providing cultured corneal endothelial cells (CECs) for clinical transplantation has gained much attention. However, the worldwide need for human (h) donor corneas far exceeds supply. The pig (p) might provide an alternative source. The aim of this study was to compare the proliferative capacity of CECs from wild-type (WT) pigs, genetically-engineered (GE) pigs, and humans. Methods The following CECs were cultured – hCECs from donors (i) ≤36 years (young), (ii) ≥49 years (old), and WT pCECs from (iii) neonatal (<5 days), (iv) young (<2 months), and (v) old (>20 months) pigs, and CECs from young (vi) GE pigs (GTKO/CD46 and GTKO/CD46/CD55). Proliferative capacity of CECs was assessed by direct cell counting over 15 days of culture and by BrdU assay. Cell viability during culture was assessed by annexin V staining. The MTT assay assessed cell metabolic activity. Results There was significantly lower proliferative capacity of old CECs than of young CECs (p<0.01) in both pigs and humans. There was no significant difference in proliferative capacity/metabolic activity between young pCECs and young hCECs. However, there was a significantly higher percentage of cell death in hCECs compared to pCECs during culture (p<0.01). Young GE pCECs showed similar proliferative capacity/cell viability/metabolic activity to young WT pCECs. Conclusions Because of the greater availability of young pigs and the excellent proliferative capacity of cultured GE pCECs, GE pigs could provide a source of CECs for clinical transplantation. PMID:23258190

Super-resolution for asymmetric resolution of FIB-SEM 3D imaging using AI with deep learning.

PubMed

Hagita, Katsumi; Higuchi, Takeshi; Jinnai, Hiroshi

2018-04-12

Scanning electron microscopy equipped with a focused ion beam (FIB-SEM) is a promising three-dimensional (3D) imaging technique for nano- and meso-scale morphologies. In FIB-SEM, the specimen surface is stripped by an ion beam and imaged by an SEM installed orthogonally to the FIB. The lateral resolution is governed by the SEM, while the depth resolution, i.e., the FIB milling direction, is determined by the thickness of the stripped thin layer. In most cases, the lateral resolution is superior to the depth resolution; hence, asymmetric resolution is generated in the 3D image. Here, we propose a new approach based on an image-processing or deep-learning-based method for super-resolution of 3D images with such asymmetric resolution, so as to restore the depth resolution to achieve symmetric resolution. The deep-learning-based method learns from high-resolution sub-images obtained via SEM and recovers low-resolution sub-images parallel to the FIB milling direction. The 3D morphologies of polymeric nano-composites are used as test images, which are subjected to the deep-learning-based method as well as conventional methods. We find that the former yields superior restoration, particularly as the asymmetric resolution is increased. Our super-resolution approach for images having asymmetric resolution enables observation time reduction.

The risk assessment of heavy metals in Futian mangrove forest sediment in Shenzhen Bay (South China) based on SEM-AVS analysis.

PubMed

Chai, Minwei; Shen, Xiaoxue; Li, Ruili; Qiu, Guoyu

2015-08-15

The risks of heavy metal in Futian mangrove forest sediment were assessed using the acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) methods. The results indicated that AVS distributions were more variable than the SEM distributions at all 16 sampling sites. The positive correlation between AVS and SEM indicated that their similar formative and existing conditions and that AVS acted as an important carrier for SEM. The major SEM component was Zn (69.7.3-94.2%), whereas the Cd contribution (the most toxic metal present) to SEM was no more than 1%. The possible adverse effects caused by heavy metals at ten sampling sites may be due to higher levels of SEMs, rather than AVSs. The total organic carbon (TOC) was an important metal-binding phase in the sediments. Taking into account the TOC concentration, there were no adverse effects due to heavy metals in any of the Futian mangrove forest sediments. Copyright © 2015 Elsevier Ltd. All rights reserved.

SEM Analysis Techniques for LSI Microcircuits. Volume 2

DTIC Science & Technology

1980-08-01

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Development of a SEM-based low-energy in-line electron holography microscope for individual particle imaging.

PubMed

Adaniya, Hidehito; Cheung, Martin; Cassidy, Cathal; Yamashita, Masao; Shintake, Tsumoru

2018-05-01

A new SEM-based in-line electron holography microscope has been under development. The microscope utilizes conventional SEM and BF-STEM functionality to allow for rapid searching of the specimen of interest, seamless interchange between SEM, BF-STEM and holographic imaging modes, and makes use of coherent low-energy in-line electron holography to obtain low-dose, high-contrast images of light element materials. We report here an overview of the instrumentation and first experimental results on gold nano-particles and carbon nano-fibers for system performance tests. Reconstructed images obtained from the holographic imaging mode of the new microscope show substantial image contrast and resolution compared to those acquired by SEM and BF-STEM modes, demonstrating the feasibility of high-contrast imaging via low-energy in-line electron holography. The prospect of utilizing the new microscope to image purified biological specimens at the individual particle level is discussed and electron optical issues and challenges to further improve resolution and contrast are considered. Copyright © 2018 Elsevier B.V. All rights reserved.

SEM Characterization of Extinguished Grains from Plasma-Ignited M30 Charges

NASA Technical Reports Server (NTRS)

Kinkennon, A.; Birk, A.; DelGuercio, M.; Kaste, P.; Lieb, R.; Newberry, J.; Pesce-Rodriguez, R.; Schroeder, M.

2000-01-01

M30 propellant grains that had been ignited in interrupted closed bomb experiments were characterize by scanning electron microscopy (SEM). Previous chemical analysis of extinguished grains had given no indications of plasma-propellant chemical interactions that could explain the increased burning rates that had been previously observed in full-pressure closed bomb experiments. (This does not mean that there is no unique chemistry occurring with plasma ignition. It may occur very early in the ignition event and then become obscured by the burning chemistry.) In this work, SEM was used to look at grain morphologies to determine if there were increases in the surface areas of the plasma-ignited grains which would contribute to the apparent increase in the burning rate. Charges were made using 30 propellant grains (approximately 32 grams) stacked in two tiers and in two concentric circles around a plastic straw. Each grain was notched so that, when the grains were expelled from the bomb during extinguishment, it could be determined in which tier and which circle each grain was originally packed. Charges were ignited in a closed bomb by either a nickel wire/Mylar-capillary plasma or black powder. The bomb contained a blowout disk that ruptured when the pressure reached 35 MPa, and the propellant was vented into a collection chamber packed with polyurethane foam. SEM analysis of the grains fired with a conventional black powder igniter showed no signs of unusual burning characteristics. The surfaces seemed to be evenly burned on the exteriors of the grains and in the perforations. Grains that had been subjected to plasma ignition, however, had pits, gouges, chasms, and cracks in the surfaces. The sides of the grains closest to the plasma had the greatest amount of damage, but even surfaces facing the outer wall of the bomb had small pits. The perforations contained gouges and abnormally burned regions (wormholes) that extended into the web. The SEM photos indicated that

SEM and AFM studies of dip-coated CuO nanofilms.

PubMed

Dhanasekaran, V; Mahalingam, T; Ganesan, V

2013-01-01

Cupric oxide (CuO) semiconducting thin films were prepared at various copper sulfate concentrations by dip coating. The copper sulfate concentration was varied to yield films of thicknesses in the range of 445-685 nm by surface profilometer. X-ray diffraction patterns revealed that the deposited films were polycrystalline in nature with monoclinic structure of (-111) plane. The surface morphology and topography of monoclinic-phase CuO thin films were examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Surface roughness profile was plotted using WSxM software and the estimated surface roughness was about ∼19.4 nm at 30 mM molar concentration. The nanosheets shaped grains were observed by SEM and AFM studies. The stoichiometric compound formation was observed at 30 mM copper sulfate concentration prepared film by EDX. The indirect band gap energy of CuO films was increased from 1.08 to 1.20 eV with the increase of copper sulfate concentrations. Copyright © 2012 Wiley Periodicals, Inc.

A hybrid 3D SEM reconstruction method optimized for complex geologic material surfaces.

PubMed

Yan, Shang; Adegbule, Aderonke; Kibbey, Tohren C G

2017-08-01

Reconstruction methods are widely used to extract three-dimensional information from scanning electron microscope (SEM) images. This paper presents a new hybrid reconstruction method that combines stereoscopic reconstruction with shape-from-shading calculations to generate highly-detailed elevation maps from SEM image pairs. The method makes use of an imaged glass sphere to determine the quantitative relationship between observed intensity and angles between the beam and surface normal, and the detector and surface normal. Two specific equations are derived to make use of image intensity information in creating the final elevation map. The equations are used together, one making use of intensities in the two images, the other making use of intensities within a single image. The method is specifically designed for SEM images captured with a single secondary electron detector, and is optimized to capture maximum detail from complex natural surfaces. The method is illustrated with a complex structured abrasive material, and a rough natural sand grain. Results show that the method is capable of capturing details such as angular surface features, varying surface roughness, and surface striations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Specimen's plane misaligned installation solution based on charge fluctuation inside SEM

NASA Astrophysics Data System (ADS)

Lu, Haojian; Liu, Yanting; Yang, Yuanyuan; Wang, Panbing; Shen, Yajing

2018-04-01

Precise specimen's installation is a sticking point to ensure the characterization accuracy of the in-situ material property test. Although it is common knowledge that specimen's plane misaligned installation (PMI) would cause extra force loading during mechanical testing, there are few effective solutions available to deal with it at the current stage, especially during the in-situ scanning electron microscopy (SEM) test. Taking into consideration the charge fluctuation phenomenon under SEM, this paper proposes a highlight area variation (HAV) method for specimen deformation judgment, i.e., the specimen deformation is defined when the highlight area changes greater than 20% of the initial value of the specimen surface. Three types of specimens with different resistivities, i.e., human hair (electrical resistivity ˜3 × 1012 Ω cm), optical fiber (electrical resistivity ˜1017 Ω cm), and magnetic wire (electrical resistivity ˜2 × 10-5 Ω cm), are chosen to verify the effectiveness of the HAV method. Furthermore, combined with the developed robot-aided alignment system, the specimen's PMI problem can also be solved. In the demonstration, the human hair specimen is installed across two specimen stages and its in-situ twisting (in 360°) test is implemented. The results clearly indicate that the HAV method and the robot-aided alignment system are practical and reliable, and the specimen can be aligned on the same plane and installed precisely with accuracy up to 3 μm. This method will benefit the in-situ SEM material mechanical property test and has a significant impact in fundamental material research.

SEM analysis of ionizing radiation effects in linear integrated circuits. [Scanning Electron Microscope

NASA Technical Reports Server (NTRS)

Stanley, A. G.; Gauthier, M. K.

1977-01-01

A successful diagnostic technique was developed using a scanning electron microscope (SEM) as a precision tool to determine ionization effects in integrated circuits. Previous SEM methods radiated the entire semiconductor chip or major areas. The large area exposure methods do not reveal the exact components which are sensitive to radiation. To locate these sensitive components a new method was developed, which consisted in successively irradiating selected components on the device chip with equal doses of electrons /10 to the 6th rad (Si)/, while the whole device was subjected to representative bias conditions. A suitable device parameter was measured in situ after each successive irradiation with the beam off.

Patterns of use and toxicity of new para-halogenated substituted cathinones: 4-CMC (clephedrone), 4-CEC (4-chloroethcatinone) and 4-BMC (brephedrone).

PubMed

Grifell, Marc; Ventura, Mireia; Carbón, Xoán; Quintana, Pol; Galindo, Liliana; Palma, Álvaro; Fornis, Ivan; Gil, Cristina; Farre, Magi; Torrens, Marta

2017-05-01

This paper aims to present results of the analysis of clephedrone (4-CMC), 4-chloroethcathinone (4-CEC), and brephedrone (4-BMC) on recreational drug markets and a systematic review of all the available information concerning these substances. Samples collected by the drug checking service of the Spanish harm reduction NGO-Energy Control were analyzed and systematic research was conducted. Between June 2014 and October 2016, 1,471 samples with at least one NPS were analyzed, 397 of which contained cathinones. Clephedrone was found in 29 samples, brephedrone in 8, and both were present in 2 samples. 4-Chloroethcathinone was detected in 5 samples. Eleven out of the 47 purchased samples (23.4%) were tested to contain the substance the user expected. Samples received were mainly sold as 3-MMC, MDMA, ketamine, and other cathinones. No literature on the effects or toxicity of these substances was found; the only information available was on internet fora. On many posts, users exhibit concerns about potential toxicity and side effects of using these substances. Since the emergence of these substances could prove to be the next step to the cat-and-mouse game existing between drug producers and legislation, further clinical and epidemiological research should be carried out in order to build evidence to support policy for public health issues. Copyright © 2017 John Wiley & Sons, Ltd.

Sol-gel synthesis, phase composition, morphological and structural characterization of Ca10(PO4)6(OH)2: XRD, FTIR, SEM, 3D SEM and solid-state NMR studies

NASA Astrophysics Data System (ADS)

Kareiva, Simonas; Klimavicius, Vytautas; Momot, Aleksandr; Kausteklis, Jonas; Prichodko, Aleksandra; Dagys, Laurynas; Ivanauskas, Feliksas; Sakirzanovas, Simas; Balevicius, Vytautas; Kareiva, Aivaras

2016-09-01

Aqueous sol-gel chemistry route based on ammonium-hydrogen phosphate as the phosphorus precursor, calcium acetate monohydrate as source of calcium ions, and 1,2-ethylendiaminetetraacetic acid (EDTA), or 1,2-diaminocyclohexanetetracetic acid (DCTA), or tartaric acid (TA), or ethylene glycol (EG), or glycerol (GL) as complexing agents have been used to prepare calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp). The phase transformations, composition, and structural changes in the polycrystalline samples were studied by infrared spectroscopy (FTIR), X-ray powder diffraction analysis (XRD), and scanning electron microscopy (SEM). The local short-range (nano- and mezo-) scale effects in CHAp were studied using solid-state NMR spectroscopy. The spatial 3D data from the SEM images of CHAp samples obtained by TA, EG and GL sol-gel routes were recovered for the first time to our knowledge.

The Role of Sexually Explicit Material (SEM) in the Sexual Development of Black Young Same-Sex-Attracted Men

PubMed Central

Morgan, Anthony; Ogunbajo, Adedotun; Trent, Maria; Harper, Gary W.; Fortenberry, J. Dennis

2015-01-01

Sexually explicit material (SEM) (including Internet, video, and print) may play a key role in the lives of Black same-sex sexually active youth by providing the only information to learn about sexual development. There is limited school-and/or family-based sex education to serve as models for sexual behaviors for Black youth. We describe the role SEM plays in the sexual development of a sample of Black same-sex attracted (SSA) young adolescent men ages 15–19. Adolescents recruited from clinics, social networking sites, and through snowball sampling were invited to participate in a 90-min, semi-structured qualitative interview. Most participants described using SEM prior to their first same-sex sexual experience. Participants described using SEM primarily for sexual development, including learning about sexual organs and function, the mechanics of same-gender sex, and to negotiate one’s sexual identity. Secondary functions were to determine readiness for sex; to learn about sexual performance, including understanding sexual roles and responsibilities (e.g., “top” or “bottom”); to introduce sexual performance scripts; and to develop models for how sex should feel (e.g., pleasure and pain). Youth also described engaging in sexual behaviors (including condom non-use and/or swallowing ejaculate) that were modeled on SEM. Comprehensive sexuality education programs should be designed to address the unmet needs of young, Black SSA young men, with explicit focus on sexual roles and behaviors that may be inaccurately portrayed and/or involve sexual risk-taking (such as unprotected anal intercourse and swallowing ejaculate) in SEM. This work also calls for development of Internet-based HIV/STI prevention strategies targeting young Black SSA men who maybe accessing SEM. PMID:25677334

Evaluating the Use of Synthetic Replicas for SEM Identification of Bloodstains (with Emphasis on Archaeological and Ethnographic Artifacts).

PubMed

Hortolà, Policarp

2015-12-01

Some archaeological or ethnographic specimens are unavailable for direct examination using a scanning electron microscope (SEM) due to methodological obstacles or legal issues. In order to assess the feasibility of using SEM synthetic replicas for the identification of bloodstains (BSs) via morphology of red blood cells (RBCs), three fragments of different natural raw material (inorganic, stone; plant, wood; animal, shell) were smeared with peripheral human blood. Afterwards, molds and casts of the bloodstained areas were made using vinyl polysiloxane (VPS) silicone impression and polyurethane (PU) resin casting material, respectively. Then, the original samples and the resulting casts were coated with gold and examined in secondary-electron mode using a high-vacuum SEM. Results suggest that PU resin casts obtained from VPS silicone molds can preserve RBC morphology in BSs, and consequently that synthetic replicas are feasible for SEM identification of BSs on cultural heritage specimens made of natural raw materials. Although the focus of this study was on BSs, the method reported in this paper may be applicable to organic residues other than blood, as well as to the surface of other specimens when, for any reason, the original is unavailable for an SEM.

Short-time pretreatment of wood with low-concentration and room-temperature ionic liquid for SEM observation.

PubMed

Yamashita, Taiji; Miyamoto, Kenji; Yonenobu, Hitoshi

2018-06-20

A new pretreatment method using room-temperature ionic liquid (IL) was proposed for observing wood specimens in scanning electron microscopy (SEM). A variety of concentrations were examined for ethanol solution of the IL, [Emim][MePO3Me], to determine an optimal pretreatment procedure. It was concluded that 10% ethanol solution of the IL was the most adequate to acquire good SEM images. Using the procedure optimized, SEM images were taken for typical anatomical types of modern soft and hardwood species and archeological wood. SEM images taken were sufficiently good in observing wood cells. The pretreatment method was also effective to archeological wood dated ca. 1600 years ago. It was thus concluded that the method developed in this study is more useful than those conventionally used. Additionally, pretreatment at the high temperature was performed to confirm morphological changes in softwood. Deformation of latewood cells (tracheids) was occurred by treating with undiluted IL at the high temperature of 50°C, probably due to higher accessibility of the IL into intercellular space. Nonetheless, it was confirmed that this happens under far more extreme conditions than our proposed method.

Evaluation of bone formation in calcium phosphate scaffolds with μCT-method validation using SEM.

PubMed

Lewin, S; Barba, A; Persson, C; Franch, J; Ginebra, M-P; Öhman-Mägi, C

2017-10-05

There is a plethora of calcium phosphate (CaP) scaffolds used as synthetic substitutes to bone grafts. The scaffold performance is often evaluated from the quantity of bone formed within or in direct contact with the scaffold. Micro-computed tomography (μCT) allows three-dimensional evaluation of bone formation inside scaffolds. However, the almost identical x-ray attenuation of CaP and bone obtrude the separation of these phases in μCT images. Commonly, segmentation of bone in μCT images is based on gray scale intensity, with manually determined global thresholds. However, image analysis methods, and methods for manual thresholding in particular, lack standardization and may consequently suffer from subjectivity. The aim of the present study was to provide a methodological framework for addressing these issues. Bone formation in two types of CaP scaffold architectures (foamed and robocast), obtained from a larger animal study (a 12 week canine animal model) was evaluated by μCT. In addition, cross-sectional scanning electron microscopy (SEM) images were acquired as references to determine thresholds and to validate the result. μCT datasets were registered to the corresponding SEM reference. Global thresholds were then determined by quantitatively correlating the different area fractions in the μCT image, towards the area fractions in the corresponding SEM image. For comparison, area fractions were also quantified using global thresholds determined manually by two different approaches. In the validation the manually determined thresholds resulted in large average errors in area fraction (up to 17%), whereas for the evaluation using SEM references, the errors were estimated to be less than 3%. Furthermore, it was found that basing the thresholds on one single SEM reference gave lower errors than determining them manually. This study provides an objective, robust and less error prone method to determine global thresholds for the evaluation of bone formation in

In situ SEM Study of Lithium Intercalation in individual V 2O 5 Nanowires

DOE PAGES

Strelcov, Evgheni; Cothren, Joshua E.; Leonard, Donovan N.; ...

2015-01-08

Progress in rational engineering of Li-ion batteries requires better understanding of the electrochemical processes and accompanying transformations in the electrode materials on multiple length scales. In spite of recent progress in utilizing transmission electron microscopy (TEM) to analyze these materials, in situ scanning electron microscopy (SEM) was mostly overlooked as a powerful tool that allows probing these phenomena on the nano and mesoscale. In this paper, we report on in situ SEM study of lithiation in a V 2O 5-based single-nanobelt battery with ionic liquid electrolyte. Coupled with cyclic voltammetry measurements, in situ SEM revealed the peculiarities of subsurface intercalation,more » formation of solid-electrolyte interface (SEI) and electromigration of liquid. We observed that single-crystalline vanadia nanobelts do not undergo large-scale amorphization or fracture during electrochemical cycling, but rather transform topochemically with only a slight shape distortion. Lastly, the SEI layer seems to have significant influence on the lithium ion diffusion and overall capacity of the single-nanobelt battery.« less

SEM image quality enhancement technology for bright field mask

NASA Astrophysics Data System (ADS)

Fukuda, Naoki; Chihara, Yuta; Shida, Soichi; Ito, Keisuke

2013-09-01

Bright-field photomasks are used to print small contact holes via ArF immersion multiple patterning lithography. There are some technical difficulties when small floating dots are to be measured by SEM tools because of a false imaging shadow. However, a new scan technology of Multi Vision Metrology SEMTM E3630 presents a solution for this issue. The combination of new scan technology and the other MVM-SEM® functions can provide further extended applications with more accurate measurement results.

Surgery on spinal epidural metastases (SEM) in renal cell carcinoma: a plea for a new paradigm.

PubMed

Bakker, Nicolaas A; Coppes, Maarten H; Vergeer, Rob A; Kuijlen, Jos M A; Groen, Rob J M

2014-09-01

Prediction models for outcome of decompressive surgical resection of spinal epidural metastases (SEM) have in common that they have been developed for all types of SEM, irrespective of the type of primary tumor. It is our experience in clinical practice, however, that these models often fail to accurately predict outcome in the individual patient. To investigate whether decision making could be optimized by applying tumor-specific prediction models. For the proof of concept, we analyzed patients with SEM from renal cell carcinoma that we have operated on. Retrospective chart analysis 2006 to 2012. Twenty-one consecutive patients with symptomatic SEM of renal cell carcinoma. Predictive factors for survival. Next to established predictive factors for survival, we analyzed the predictive value of the Motzer criteria in these patients. The Motzer criteria comprise a specific and validated risk model for survival in patients with renal cell carcinoma. After multivariable analysis, only Motzer intermediate (hazard ratio [HR] 17.4, 95% confidence interval [CI] 1.82-166, p=.01) and high risk (HR 39.3, 95% CI 3.10-499, p=.005) turned out to be significantly associated with survival in patients with renal cell carcinoma that we have operated on. In this study, we have demonstrated that decision making could have been optimized by implementing the Motzer criteria next to established prediction models. We, therefore, suggest that in future, in patients with SEM from renal cell carcinoma, the Motzer criteria are also taken into account. Copyright © 2014 Elsevier Inc. All rights reserved.

Fluid phase biopsy for detection and characterization of circulating endothelial cells in myocardial infarction

NASA Astrophysics Data System (ADS)

Bethel, Kelly; Luttgen, Madelyn S.; Damani, Samir; Kolatkar, Anand; Lamy, Rachelle; Sabouri-Ghomi, Mohsen; Topol, Sarah; Topol, Eric J.; Kuhn, Peter

2014-02-01

Elevated levels of circulating endothelial cells (CECs) occur in response to various pathological conditions including myocardial infarction (MI). Here, we adapted a fluid phase biopsy technology platform that successfully detects circulating tumor cells in the blood of cancer patients (HD-CTC assay), to create a high-definition circulating endothelial cell (HD-CEC) assay for the detection and characterization of CECs. Peripheral blood samples were collected from 79 MI patients, 25 healthy controls and six patients undergoing vascular surgery (VS). CECs were defined by positive staining for DAPI, CD146 and von Willebrand Factor and negative staining for CD45. In addition, CECs exhibited distinct morphological features that enable differentiation from surrounding white blood cells. CECs were found both as individual cells and as aggregates. CEC numbers were higher in MI patients compared with healthy controls. VS patients had lower CEC counts when compared with MI patients but were not different from healthy controls. Both HD-CEC and CellSearch® assays could discriminate MI patients from healthy controls with comparable accuracy but the HD-CEC assay exhibited higher specificity while maintaining high sensitivity. Our HD-CEC assay may be used as a robust diagnostic biomarker in MI patients.

Electron Beam Irradiation Induced Multiwalled Carbon Nanotubes Fusion inside SEM.

PubMed

Shen, Daming; Chen, Donglei; Yang, Zhan; Liu, Huicong; Chen, Tao; Sun, Lining; Fukuda, Toshio

2017-01-01

This paper reported a method of multiwalled carbon nanotubes (MWCNTs) fusion inside a scanning electron microscope (SEM). A CNT was picked up by nanorobotics manipulator system which was constructed in SEM with 21 DOFs and 1 nm resolution. The CNT was picked up and placed on two manipulators. The tensile force was 140 nN when the CNT was pulled into two parts. Then, two parts of the CNT were connected to each other by two manipulators. The adhered force between two parts was measured to be about 20 nN. When the two parts of CNT were connected again, the contact area was fused by focused electron beam irradiation for 3 minutes. The tensile force of the junction was measured to be about 100 nN. However, after fusion, the tensile force was five times larger than the tensile force connected only by van der Waals force. This force was 70 percent of the tensile force before pulling out of CNTs. The results revealed that the electron beam irradiation was a promising method for CNT fusion. We hope this technology will be applied to nanoelectronics in the near future.

A SEM-correlation of the anatomy of the vitreous body: making visible the invisible.

PubMed

Jongebloed, W L; Humalda, D; Worst, J F

1986-12-30

The naked human vitreous (sclera, iris and cornea removed) suspended in water does not reveal inner structures. After ink injection into the vitreous, the presence of different compartments and the existence of cisterns becomes evident. A concept of the internal system of cisterns is given on the basis of stereoscopic-lightmicroscopic images. An attempt is made to correlate images of the complete vitreous body, obtained with a stereo-lightmicroscope, with images of segments of cisternal walls produced with a scanning electron-microscope (SEM). A comparison is made between SEM-images of the vitreous bodies of human and rabbit eyes.

Characterization of Polycapillary Optics in a TES Microcalorimeter EDS System Installed on an SEM

NASA Astrophysics Data System (ADS)

Takano, A.; Maehata, K.; Iyomoto, N.; Yasuda, K.; Maeno, H.; Shiiyama, K.; Tanaka, K.

2016-08-01

Energy-dispersive spectroscopic measurements are performed using a superconducting transition-edge sensor (TES) microcalorimeter mounted on a scanning electron microscope (SEM) for advanced research at Kyushu University. Because the sensitive area of the TES microcalorimeter is about 0.02~mm2, polycapillary optics is used to collect the X-rays emitted by the SEM specimen on the TES microcalorimeter. The X-ray transmission efficiency of the polycapillary optics is obtained by analyzing the X-ray energy spectra measured by the TES microcalorimeter. The obtained transmission efficiency of the polycapillary optics is reproduced by the calculated results of the simulation.

High-resolution 3D analyses of the shape and internal constituents of small volcanic ash particles: The contribution of SEM micro-computed tomography (SEM micro-CT)

NASA Astrophysics Data System (ADS)

Vonlanthen, Pierre; Rausch, Juanita; Ketcham, Richard A.; Putlitz, Benita; Baumgartner, Lukas P.; Grobéty, Bernard

2015-02-01

The morphology of small volcanic ash particles is fundamental to our understanding of magma fragmentation, and in transport modeling of volcanic plumes and clouds. Until recently, the analysis of 3D features in small objects (< 250 μm) was either restricted to extrapolations from 2D approaches, partial stereo-imaging, or CT methods having limited spatial resolution and/or accessibility. In this study, an X-ray computed-tomography technique known as SEM micro-CT, also called 3D X-ray ultramicroscopy (3D XuM), was used to investigate the 3D morphology of small volcanic ash particles (125-250 μm sieve fraction), as well as their vesicle and microcrystal distribution. The samples were selected from four stratigraphically well-established tephra layers of the Meerfelder Maar (West Eifel Volcanic Field, Germany). Resolution tests performed on a Beametr v1 pattern sample along with Monte Carlo simulations of X-ray emission volumes indicated that a spatial resolution of 0.65 μm was obtained for X-ray shadow projections using a standard thermionic SEM and a bulk brass target as X-ray source. Analysis of a smaller volcanic ash particle (64-125 μm sieve fraction) showed that features with volumes > 20 μm3 (~ 3.5 μm in diameter) can be successfully reconstructed and quantified. In addition, new functionalities of the Blob3D software were developed to allow the particle shape factors frequently used as input parameters in ash transport and dispersion models to be calculated. This study indicates that SEM micro-CT is very well suited to quantify the various aspects of shape in fine volcanic ash, and potentially also to investigate the 3D morphology and internal structure of any object < 0.1 mm3.

Prophylometric and SEM analyses of four different finishing methods

PubMed Central

CHIODERA, G.; CERUTTI, F.; CERUTTI, A.; PUTIGNANO, A.; MANGANI, F.

2013-01-01

Summary Adhesion is the pivot of the modern restorative dentistry. Inlays, onlays and veneers have become a valid alternative to the traditional prosthetic treatments even in the rehabilitation of extremely damaged teeth, allowing a consistent saving of sound tooth tissues. Composite resins and dental adhesive are continously investigated and improved, nevertheless the optimization of the tooth-adhesive interface has to be considered: in fact, the long-term stability of adhesion between tooth and composite material depends on the treatment of the amelo-dentinal surfaces. This study investigated the quality of the occlusal walls of a cavity prepared to receive an inlay and finished with four different systems: thin and extra-thin diamond coated burs, a 12-blades carbide burs and a diamond-coated tip driven by sonic instrument. Consequently, prophylometric and SEM analyses were performed on the samples. The average roughness values recorded by the prophylometer were expressed by the parameters Ra and RZ: there is a correspondence between the numeric values and the pictures of the SEM. The results show a better quality (low roughness values) of the surface treated with multi-blade burs, followed by the this and extra-thin diamond coated burs. The 25 micron diamond-coated tip of the sonic instrument obtains the roughest surface and a sensibly higher amount of smear layer than the other tested systems. PMID:23741601

Tracing outbreaks of Streptococcus equi infection (strangles) in horses using sequence variation in the seM gene and pulsed-field gel electrophoresis.

PubMed

Lindahl, Susanne; Söderlund, Robert; Frosth, Sara; Pringle, John; Båverud, Viveca; Aspán, Anna

2011-11-21

Strangles is a serious respiratory disease in horses caused by Streptococcus equi subspecies equi (S. equi). Transmission of the disease occurs by direct contact with an infected horse or contaminated equipment. Genetically, S. equi strains are highly homogenous and differentiation of strains has proven difficult. However, the S. equi M-protein SeM contains a variable N-terminal region and has been proposed as a target gene to distinguish between different strains of S. equi and determine the source of an outbreak. In this study, strains of S. equi (n=60) from 32 strangles outbreaks in Sweden during 1998-2003 and 2008-2009 were genetically characterized by sequencing the SeM protein gene (seM), and by pulsed-field gel electrophoresis (PFGE). Swedish strains belonged to 10 different seM types, of which five have not previously been described. Most were identical or highly similar to allele types from strangles outbreaks in the UK. Outbreaks in 2008/2009 sharing the same seM type were associated by geographic location and/or type of usage of the horses (racing stables). Sequencing of the seM gene generally agreed with pulsed-field gel electrophoresis profiles. Our data suggest that seM sequencing as a epidemiological tool is supported by the agreement between seM and PFGE and that sequencing of the SeM protein gene is more sensitive than PFGE in discriminating strains of S. equi. Copyright © 2011 Elsevier B.V. All rights reserved.

SEM-induced shrinkage and site-selective modification of single-crystal silicon nanopores

NASA Astrophysics Data System (ADS)

Chen, Qi; Wang, Yifan; Deng, Tao; Liu, Zewen

2017-07-01

Solid-state nanopores with feature sizes around 5 nm play a critical role in bio-sensing fields, especially in single molecule detection and sequencing of DNA, RNA and proteins. In this paper we present a systematic study on shrinkage and site-selective modification of single-crystal silicon nanopores with a conventional scanning electron microscope (SEM). Square nanopores with measurable sizes as small as 8 nm × 8 nm and rectangle nanopores with feature sizes (the smaller one between length and width) down to 5 nm have been obtained, using the SEM-induced shrinkage technique. The analysis of energy dispersive x-ray spectroscopy and the recovery of the pore size and morphology reveal that the grown material along with the edge of the nanopore is the result of deposition of hydrocarbon compounds, without structural damage during the shrinking process. A simplified model for pore shrinkage has been developed based on observation of the cross-sectional morphology of the shrunk nanopore. The main factors impacting on the task of controllably shrinking the nanopores, such as the accelerating voltage, spot size, scanned area of e-beam, and the initial pore size have been discussed. It is found that single-crystal silicon nanopores shrink linearly with time under localized irradiation by SEM e-beam in all cases, and the pore shrinkage rate is inversely proportional to the initial equivalent diameter of the pore under the same e-beam conditions.

Teacher's Corner: Structural Equation Modeling with the Sem Package in R

ERIC Educational Resources Information Center

Fox, John

2006-01-01

R is free, open-source, cooperatively developed software that implements the S statistical programming language and computing environment. The current capabilities of R are extensive, and it is in wide use, especially among statisticians. The sem package provides basic structural equation modeling facilities in R, including the ability to fit…

Contrast of Backscattered Electron SEM Images of Nanoparticles on Substrates with Complex Structure.

PubMed

Kowoll, Thomas; Müller, Erich; Fritsch-Decker, Susanne; Hettler, Simon; Störmer, Heike; Weiss, Carsten; Gerthsen, Dagmar

2017-01-01

This study is concerned with backscattered electron scanning electron microscopy (BSE SEM) contrast of complex nanoscaled samples which consist of SiO 2 nanoparticles (NPs) deposited on indium-tin-oxide covered bulk SiO 2 and glassy carbon substrates. BSE SEM contrast of NPs is studied as function of the primary electron energy and working distance. Contrast inversions are observed which prevent intuitive interpretation of NP contrast in terms of material contrast. Experimental data is quantitatively compared with Monte-Carlo- (MC-) simulations. Quantitative agreement between experimental data and MC-simulations is obtained if the transmission characteristics of the annular semiconductor detector are taken into account. MC-simulations facilitate the understanding of NP contrast inversions and are helpful to derive conditions for optimum material and topography contrast.

X-ray diffraction, FTIR, UV-VIS and SEM studies on chromium (III) complexes

NASA Astrophysics Data System (ADS)

Mishra, Ashutosh; Dwivedi, Jagrati; Shukla, Kritika

2015-06-01

Five Chromium (III) complexes have been prepared using Schiff base ligands which derived from benzoin and five different amino acids (H2N-R). Samples were characterized by XRD, FTIR, UV-VIS and SEM method. X-Ray diffraction pattern analyzed that all chromium (III) complexes have hexagonal structure and crystalline, in nature, using Bruker D8 Advance instrument. Using VERTAX 70, FTIR spectroscopy reveals that Samples have (C=N), (C-O), (M-N) and (M-O) bonds in the range of 4000-400cm-1. UV-VIS spectroscopy give information that samples absorb the visible light which is in the range of 380-780nm. For this, Lambda 960 spectrometer used. SEM is designed for studying of the solid objects, using JEOL JSM 5600 instrument.

Faults and foibles of quantitative scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS)

NASA Astrophysics Data System (ADS)

Newbury, Dale E.; Ritchie, Nicholas W. M.

2012-06-01

Scanning electron microscopy with energy dispersive x-ray spectrometry (SEM/EDS) is a powerful and flexible elemental analysis method that can identify and quantify elements with atomic numbers > 4 (Be) present as major constituents (where the concentration C > 0.1 mass fraction, or 10 weight percent), minor (0.01<= C <= 0.1) and trace (C < 0.01, with a minimum detectable limit of ~+/- 0.0005 - 0.001 under routine measurement conditions, a level which is analyte and matrix dependent ). SEM/EDS can select specimen volumes with linear dimensions from ~ 500 nm to 5 μm depending on composition (masses ranging from ~ 10 pg to 100 pg) and can provide compositional maps that depict lateral elemental distributions. Despite the maturity of SEM/EDS, which has a history of more than 40 years, and the sophistication of modern analytical software, the method is vulnerable to serious shortcomings that can lead to incorrect elemental identifications and quantification errors that significantly exceed reasonable expectations. This paper will describe shortcomings in peak identification procedures, limitations on the accuracy of quantitative analysis due to specimen topography or failures in physical models for matrix corrections, and quantitative artifacts encountered in xray elemental mapping. Effective solutions to these problems are based on understanding the causes and then establishing appropriate measurement science protocols. NIST DTSA II and Lispix are open source analytical software available free at www.nist.gov that can aid the analyst in overcoming significant limitations to SEM/EDS.

SEM visualization of glycosylated surface molecules using lectin-coated microspheres

NASA Technical Reports Server (NTRS)

Duke, J.; Janer, L.; Campbell, M.

1985-01-01

There are several techniques currently used to localize glycosylated surface molecules by scanning electron microscopy (Grinnell, 1980; Molday, 1976; Linthicum and Sell, 1975; Nicolson, 1974; Lo Buglio, et al, 1972). A simple and rapid method, using a modification of Grinnell's technique is reported here. Essentially, microspheres coated with Concavalin A are used to bind to glycosylated regions of the palatal shelf epithelium and are visualized in the scanning electron microscope (SEM).

One-Step Hydrothermal Synthesis of Zeolite X Powder from Natural Low-Grade Diatomite.

PubMed

Yao, Guangyuan; Lei, Jingjing; Zhang, Xiaoyu; Sun, Zhiming; Zheng, Shuilin

2018-05-28

Zeolite X powder was synthesized using natural low-grade diatomite as the main source of Si but only as a partial source of Al via a simple and green hydrothermal method. The microstructure and surface properties of the obtained samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), wavelength dispersive X-ray fluorescence (XRF), calcium ion exchange capacity (CEC), thermogravimetric-differential thermal (TG-DTA) analysis, and N₂ adsorption-desorption technique. The influence of various synthesis factors, including aging time and temperature, crystallization time and temperature, Na₂O/SiO₂ and H₂O/Na₂O ratio on the CEC of zeolite, were systematically investigated. The as-synthesized zeolite X with binary meso-microporous structure possessed remarkable thermal stability, high calcium ion exchange capacity of 248 mg/g and large surface area of 453 m²/g. In addition, the calcium ion exchange capacity of zeolite X was found to be mainly determined by the crystallization degree. In conclusion, the synthesized zeolite X using diatomite as a cost-effective raw material in this study has great potential for industrial application such as catalyst support and adsorbent.

SEMS: System for Environmental Monitoring and Sustainability

NASA Technical Reports Server (NTRS)

Arvidson, Raymond E.

1998-01-01

The goal of this project was to establish a computational and data management system, SEMS, building on our existing system and MTPE-related research. We proposed that the new system would help support Washington University's efforts in environmental sustainability through use in: (a) Problem-based environmental curriculum for freshmen and sophomores funded by the Hewlett Foundation that integrates scientific, cultural, and policy perspectives to understand the dynamics of wetland degradation, deforestation, and desertification and that will develop policies for sustainable environments and economies; (b) Higher-level undergraduate and graduate courses focused on monitoring the environment and developing policies that will lead to sustainable environmental and economic conditions; and (c) Interdisciplinary research focused on the dynamics of the Missouri River system and development of policies that lead to sustainable environmental and economic floodplain conditions.

Comparison of ethical judgments exhibited by clients and ethics consultants in Japan.

PubMed

Nagao, Noriko; Kadooka, Yasuhiro; Asai, Atsushi

2014-03-04

Healthcare professionals must make decisions for patients based on ethical considerations. However, they rely on clinical ethics consultations (CEC) to review ethical justifications of their decisions. CEC consultants support the cases reviewed and guide medical care. When both healthcare professionals and CEC consultants face ethical problems in medical care, how is their judgment derived? How do medical judgments differ from the ethical considerations of CECs? This study examines CECs in Japan to identify differences in the ethical judgment of clients and CEC consultants. The CEC request and response documents of all 60 cases reviewed across Japan between October 2006 and the end of October 2011 were classified in terms of the presence of decisional capacity in the patient. We conducted a qualitative content analysis of the differences in reasoning between client and CEC consultants. Reasoned judgments were verified in individual cases to classify the similarities or differences of opinion between CEC clients and teams. As the result of classification of the decisional capacity and the difference of opinion regarding medical care, the most frequent category was 25 cases (41.7%) of "uncertain decisional capacity," and 23 cases (38.3%) of "withholding of decision-making." A chi-square analysis was performed on presence of decisional capacity and agreement in decision-making, yielding a statistically significant difference (p < 0.05). The CEC consultants' reasoning was based on "patient's preference was ambiguous," "validity of family as a surrogate," "estimation of patient preference," and "patient's best interest," whereas the CEC client's reasoning was based on "consistent family preference was shown/not shown" and "appropriate therapeutic methods to manage patient safety." Differences in opinions were found in cases classified according to decisional capacity. Furthermore, the reasoning behind judgments differed between CEC clients and CEC consultants. The

Is scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) quantitative?

PubMed

Newbury, Dale E; Ritchie, Nicholas W M

2013-01-01

Scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) is a widely applied elemental microanalysis method capable of identifying and quantifying all elements in the periodic table except H, He, and Li. By following the "k-ratio" (unknown/standard) measurement protocol development for electron-excited wavelength dispersive spectrometry (WDS), SEM/EDS can achieve accuracy and precision equivalent to WDS and at substantially lower electron dose, even when severe X-ray peak overlaps occur, provided sufficient counts are recorded. Achieving this level of performance is now much more practical with the advent of the high-throughput silicon drift detector energy dispersive X-ray spectrometer (SDD-EDS). However, three measurement issues continue to diminish the impact of SEM/EDS: (1) In the qualitative analysis (i.e., element identification) that must precede quantitative analysis, at least some current and many legacy software systems are vulnerable to occasional misidentification of major constituent peaks, with the frequency of misidentifications rising significantly for minor and trace constituents. (2) The use of standardless analysis, which is subject to much broader systematic errors, leads to quantitative results that, while useful, do not have sufficient accuracy to solve critical problems, e.g. determining the formula of a compound. (3) EDS spectrometers have such a large volume of acceptance that apparently credible spectra can be obtained from specimens with complex topography that introduce uncontrolled geometric factors that modify X-ray generation and propagation, resulting in very large systematic errors, often a factor of ten or more. © Wiley Periodicals, Inc.

Endobacterial morphotypes in nudibranch cerata tips: a SEM analysis

NASA Astrophysics Data System (ADS)

Schuett, Christian; Doepke, Hilke

2013-06-01

The SEM investigation of nudibranch cerata material exhibits endobacterial morphotypes found in 12 out of 13 species tested: Aeolidia papillosa, Berghia caerulescens, Coryphella brownii, Coryphella lineata, Coryphella verrucosa, Cuthona amoena, Facelina coronata, Flabellina pedata, Dendronotus frondosus, Doto coronata, Tritonia plebeia and Janolus cristatus. Endobacteria could not be detected inside Tritonia hombergi. Endobacterial morphology found inside nudibranch species was compared to bacterial morphotypes detected earlier in tentacles of cnidarian species. SEM micrographs show endobacterial analogy among nudibranch species, but also similarity to cnidarian endobacteria investigated earlier. Of course, morphological data of microbes do not allow their identification. However, since most of these nudibranch species prey on cnidaria, it cannot be excluded that many of the endobacteria detected inside nudibranch species may originate from their cnidarian prey. Our previous data describing genetic affiliation of endobacteria from nudibranchian and cnidarian species support this assumption. Dominant coccoid endobacteria mostly exhibit smooth surface and are tightly packed as aggregates and/or wrapped in envelopes. Such bacterial aggregate type has been described previously in tentacles of the cnidarian species Sagartia elegans. Similar coccoid bacteria, lacking envelopes were also found in other nudibranch species. A different type of coccoid bacteria, characterized by a rough surface, was detected inside cerata of the nudibranch species Berghia caerulescens, and surprisingly, inside tentacles of the cnidarian species Tubularia indivisa. In contrast to cnidarian endobacteria, rod-shaped microorganisms are largely absent in nudibranch cerata.

CD-SEM metrology and OPC modeling for 2D patterning in advanced technology nodes (Conference Presentation)

NASA Astrophysics Data System (ADS)

Wallow, Thomas I.; Zhang, Chen; Fumar-Pici, Anita; Chen, Jun; Laenens, Bart; Spence, Christopher A.; Rio, David; van Adrichem, Paul; Dillen, Harm; Wang, Jing; Yang, Peng-Cheng; Gillijns, Werner; Jaenen, Patrick; van Roey, Frieda; van de Kerkhove, Jeroen; Babin, Sergey

2017-03-01

In the course of assessing OPC compact modeling capabilities and future requirements, we chose to investigate the interface between CD-SEM metrology methods and OPC modeling in some detail. Two linked observations motivated our study: 1) OPC modeling is, in principle, agnostic of metrology methods and best practice implementation. 2) Metrology teams across the industry use a wide variety of equipment, hardware settings, and image/data analysis methods to generate the large volumes of CD-SEM measurement data that are required for OPC in advanced technology nodes. Initial analyses led to the conclusion that many independent best practice metrology choices based on systematic study as well as accumulated institutional knowledge and experience can be reasonably made. Furthermore, these choices can result in substantial variations in measurement of otherwise identical model calibration and verification patterns. We will describe several experimental 2D test cases (i.e., metal, via/cut layers) that examine how systematic changes in metrology practice impact both the metrology data itself and the resulting full chip compact model behavior. Assessment of specific methodology choices will include: • CD-SEM hardware configurations and settings: these may range from SEM beam conditions (voltage, current, etc.,) to magnification, to frame integration optimizations that balance signal-to-noise vs. resist damage. • Image and measurement optimization: these may include choice of smoothing filters for noise suppression, threshold settings, etc. • Pattern measurement methodologies: these may include sampling strategies, CD- and contour- based approaches, and various strategies to optimize the measurement of complex 2D shapes. In addition, we will present conceptual frameworks and experimental methods that allow practitioners of OPC metrology to assess impacts of metrology best practice choices on model behavior. Finally, we will also assess requirements posed by node scaling

The SEM Risk Behavior (SRB) Model: A New Conceptual Model of how Pornography Influences the Sexual Intentions and HIV Risk Behavior of MSM.

PubMed

Wilkerson, J Michael; Iantaffi, Alex; Smolenski, Derek J; Brady, Sonya S; Horvath, Keith J; Grey, Jeremy A; Rosser, B R Simon

2012-01-01

While the effects of sexually explicit media (SEM) on heterosexuals' sexual intentions and behaviors have been studied, little is known about the consumption and possible influence of SEM among men who have sex with men (MSM). Importantly, conceptual models of how Internet-based SEM influences behavior are lacking. Seventy-nine MSM participated in online focus groups about their SEM viewing preferences and sexual behavior. Twenty-three participants reported recent exposure to a new behavior via SEM. Whether participants modified their sexual intentions and/or engaged in the new behavior depended on three factors: arousal when imagining the behavior, pleasure when attempting the behavior, and trust between sex partners. Based on MSM's experience, we advance a model of how viewing a new sexual behavior in SEM influences sexual intentions and behaviors. The model includes five paths. Three paths result in the maintenance of sexual intentions and behaviors. One path results in a modification of sexual intentions while maintaining previous sexual behaviors, and one path results in a modification of both sexual intentions and behaviors. With this model, researchers have a framework to test associations between SEM consumption and sexual intentions and behavior, and public health programs have a framework to conceptualize SEM-based HIV/STI prevention programs.

The SEM Risk Behavior (SRB) Model: A New Conceptual Model of how Pornography Influences the Sexual Intentions and HIV Risk Behavior of MSM

PubMed Central

Wilkerson, J. Michael; Iantaffi, Alex; Smolenski, Derek J.; Brady, Sonya S.; Horvath, Keith J.; Grey, Jeremy A.; Rosser, B. R. Simon

2012-01-01

While the effects of sexually explicit media (SEM) on heterosexuals’ sexual intentions and behaviors have been studied, little is known about the consumption and possible influence of SEM among men who have sex with men (MSM). Importantly, conceptual models of how Internet-based SEM influences behavior are lacking. Seventy-nine MSM participated in online focus groups about their SEM viewing preferences and sexual behavior. Twenty-three participants reported recent exposure to a new behavior via SEM. Whether participants modified their sexual intentions and/or engaged in the new behavior depended on three factors: arousal when imagining the behavior, pleasure when attempting the behavior, and trust between sex partners. Based on MSM’s experience, we advance a model of how viewing a new sexual behavior in SEM influences sexual intentions and behaviors. The model includes five paths. Three paths result in the maintenance of sexual intentions and behaviors. One path results in a modification of sexual intentions while maintaining previous sexual behaviors, and one path results in a modification of both sexual intentions and behaviors. With this model, researchers have a framework to test associations between SEM consumption and sexual intentions and behavior, and public health programs have a framework to conceptualize SEM-based HIV/STI prevention programs. PMID:23185126

The detection of metallic residues in skin stab wounds by means of SEM-EDS: A pilot study.

PubMed

Palazzo, Elisa; Amadasi, Alberto; Boracchi, Michele; Gentile, Guendalina; Maciocco, Francesca; Marchesi, Matteo; Zoja, Riccardo

2018-05-01

The morphological analysis of stab wounds may often not be accurate enough to link it with the type of wounding weapon, but a further evaluation may be performed with the search for metallic residues left during the contact between the instrument and the skin. In this study, Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) was applied to the study of cadaveric stab wounds performed with kitchen knives composed of iron, chromium and nickel, in order to verify the presence of metallic residues on the wound's edge. Two groups of 10 corpses were selected: group A, including victims of stab wounds and a control group B (died of natural causes). Samplings were performed on the lesions and in intact areas of group A, whereas in group B sampling were performed in non-exposed intact skin. Samples were then analysed with optical microscopy and SEM-EDS. In group A, optical microscopic analysis showed the presence of vital haemorrhagic infiltration, while SEM-EDS showed evidence of microscopic metal traces, isolated or clustered, consisting of iron, chromium and nickel. Moreover, in two cases organic residues of calcium and phosphate were detected, as a probable sign of bone lesion. Control samples (group A in intact areas and group B), were negative for the search of exogenous material to optical microscopy and SEM-EDS. The results show the utility and possible application of the SEM-EDS in theidentification of metallic residues from sharp weapons on the skin. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

Comparison of selective staining of fungi in paraffin sections by light microscopy, SEM and BEI

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

Berman, E.L.; Laudate, A.; Carter, H.W.

Paraffin-embedded sections from human tissues with fungi or organisms classified with fungi were studied by light microscopy (LM), scanning electron microscopy (SEM), and the backscatter electron imaging (BEI) mode of the SEM. The fungal organisms selected for study were those familiar to the pathologist on the basis of their appearance in paraffin-embedded material stained with the Gomori-Grocott Chromic Acid Methenamine Silver Stain (GMS). The organisms were Actinomyces, Rhizopus, Cryptococcus, Histoplasma capsulatum, and Coccidia imitis. Sections were stained with the GMS Stain and/or the Becker modification of the GMS Stain (BGMS) and examined in the secondary electron imaging mode (SEI) andmore » BEI mode with an annular backscatter electron detector. This silver staining technique accentuated the wall of fungal organisms, in the backscatter mode. Depending on the fungal organism and type of silver stain employed, the GMS seemed the preferable stain. The advantages of SEM over LM were greater depth of focus and potential range of magnifications. BEI may also be used in conjunction with LM stain for microorganisms to establish their presence.« less

[Recent advances and applications of capillary electrochromatography and pressurized capillary electrochromatography].

PubMed

Wu, Yi; Zhang, Xiaohui; Wei, Juan; Xue, Yunyun; Bahatibieke, Marjan; Wang, Yan; Yan, Chao

2009-09-01

Capillary electrochromatography (CEC), in which electroosmotic flow (EOF) created from the electrical double layer is made to act as a pump to drive the mobile phase in a capillary column packed with micro-particulates or coated with stationary phase. Both neutral and charged species can be resolved by CEC. It has been demonstrated that the efficiency of a separation obtained by electroosmotic propulsion is superior to that obtained by pressure-driven flow (as is the case in HPLC). CEC combines the best features of CE and versatile selectivity and large sample capacity of HPLC, promising high efficiency, high resolution, high selectivity and high peak capacity. However, in practice, when CEC is used without pressure, often used on a commercial CE instrument, there are problems and difficulties associated with bubbles formation and column dry-out. These difficulties can be overcome by a pressurized CEC (pCEC) system, in which a supplementary pressure is applied to the column in addition to the EOF. In such a system, a pressure can be applied to the capillary column to suppress bubbles formation. Quantitative sample introduction in pCEC can be easily achieved through a rotary-type injector. Most importantly, it is amenable for a solvent gradient mode, similar to that in HPLC, by programming the composition of mobile phase. The article brings a comprehensive survey of recent development of CEC and pCEC, including the development of instrumentation, capillary columns and stationary phase as well as CEC and pCEC applications in life science, biotechnology, pharmaceutical analysis, food safety and environmental security. Prospects for CEC and pCEC development and application are also discussed.

Contrast of Backscattered Electron SEM Images of Nanoparticles on Substrates with Complex Structure

PubMed Central

Müller, Erich; Fritsch-Decker, Susanne; Hettler, Simon; Störmer, Heike; Weiss, Carsten; Gerthsen, Dagmar

2017-01-01

This study is concerned with backscattered electron scanning electron microscopy (BSE SEM) contrast of complex nanoscaled samples which consist of SiO2 nanoparticles (NPs) deposited on indium-tin-oxide covered bulk SiO2 and glassy carbon substrates. BSE SEM contrast of NPs is studied as function of the primary electron energy and working distance. Contrast inversions are observed which prevent intuitive interpretation of NP contrast in terms of material contrast. Experimental data is quantitatively compared with Monte-Carlo- (MC-) simulations. Quantitative agreement between experimental data and MC-simulations is obtained if the transmission characteristics of the annular semiconductor detector are taken into account. MC-simulations facilitate the understanding of NP contrast inversions and are helpful to derive conditions for optimum material and topography contrast. PMID:29109816

RBS, TEM and SEM Characterization of Gold Nanoclusters in TiO2(110)

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

Shutthanandan, V; Zhang, Yanwen; Wang, Chong M.

2004-05-01

Nucleation of gold nanoclusters in TiO2(110) single crystal using ion implantation and subsequent annealing were studied by Rutherford backscattering spectrometry /channeling (RBS/C), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Approximately 1000 Au2+/nm2 was implanted at room temperature in TiO2(110) substrates. TEM and SEM measurements revel that rounded nanoclusters were formed during the implantation. In contrast subsequent annealing in air for 10 hours at 1275 K promoted the formation of faceted (rectangular shaped) Au nano structures in TiO2. RBS channeling measurements further reveled that Au atoms randomly occupied in the host TiO2 lattice during the implantation. However, some ofmore » the gold atoms were moved into the Ti lattice position after annealing.« less

Estimating Soil Cation Exchange Capacity from Soil Physical and Chemical Properties

NASA Astrophysics Data System (ADS)

Bateni, S. M.; Emamgholizadeh, S.; Shahsavani, D.

2014-12-01

The soil Cation Exchange Capacity (CEC) is an important soil characteristic that has many applications in soil science and environmental studies. For example, CEC influences soil fertility by controlling the exchange of ions in the soil. Measurement of CEC is costly and difficult. Consequently, several studies attempted to obtain CEC from readily measurable soil physical and chemical properties such as soil pH, organic matter, soil texture, bulk density, and particle size distribution. These studies have often used multiple regression or artificial neural network models. Regression-based models cannot capture the intricate relationship between CEC and soil physical and chemical attributes and provide inaccurate CEC estimates. Although neural network models perform better than regression methods, they act like a black-box and cannot generate an explicit expression for retrieval of CEC from soil properties. In a departure with regression and neural network models, this study uses Genetic Expression Programming (GEP) and Multivariate Adaptive Regression Splines (MARS) to estimate CEC from easily measurable soil variables such as clay, pH, and OM. CEC estimates from GEP and MARS are compared with measurements at two field sites in Iran. Results show that GEP and MARS can estimate CEC accurately. Also, the MARS model performs slightly better than GEP. Finally, a sensitivity test indicates that organic matter and pH have respectively the least and the most significant impact on CEC.

In vitro biomimetic platforms featuring a perfusion system and 3D spheroid culture promote the construction of tissue-engineered corneal endothelial layers.

PubMed

Li, Shanyi; Han, Yuting; Lei, Hao; Zeng, Yingxin; Cui, Zekai; Zeng, Qiaolang; Zhu, Deliang; Lian, Ruiling; Zhang, Jun; Chen, Zhe; Chen, Jiansu

2017-04-10

Corneal endothelial cells (CECs) are very important for the maintenance of corneal transparency. However, in vitro, CECs display limited proliferation and loss of phenotype via endothelial to mesenchymal transformation (EMT) and cellular senescence. In this study, we demonstrate that continuous supplementary nutrition using a perfusion culture bioreactor and three-dimensional (3D) spheroid culture can be used to improve CEC expansion in culture and to construct a tissue-engineered CEC layer. Compared with static culture, perfusion-derived CECs exhibited an increased proliferative ability as well as formed close cell-cell contact junctions and numerous surface microvilli. We also demonstrated that the CEC spheroid culture significantly down-regulated gene expression of the proliferation marker Ki67 and EMT-related markers Vimentin and α-SMA, whereas the gene expression level of the CEC marker ATP1A1 was significantly up-regulated. Furthermore, use of the perfusion system in conjunction with a spheroid culture on decellularized corneal scaffolds and collagen sheets promoted the generation of CEC monolayers as well as neo-synthesized ECM formation. This study also confirmed that a CEC spheroid culture on a curved collagen sheet with controlled physiological intraocular pressure could generate a CEC monolayer. Thus, our results show that the use of a perfusion system and 3D spheroid culture can promote CEC expansion and the construction of tissue-engineered corneal endothelial layers in vitro.

Nanomanufacturing Concerns about Measurements Made in the SEM Part IV: Charging and its Mitigation.

PubMed

Postek, Michael T; Vladár, András E

2015-01-01

This is the fourth part of a series of tutorial papers discussing various causes of measurement uncertainty in scanned particle beam instruments, and some of the solutions researched and developed at NIST and other research institutions. Scanned particle beam instruments especially the scanning electron microscope (SEM) have gone through tremendous evolution to become indispensable tools for many and diverse scientific and industrial applications. These improvements have significantly enhanced their performance and made them far easier to operate. But, the ease of operation has also fostered operator complacency. In addition, the user-friendliness has reduced the apparent need for extensive operator training. Unfortunately, this has led to the idea that the SEM is just another expensive "digital camera" or another peripheral device connected to a computer and that all of the problems in obtaining good quality images and data have been solved. Hence, one using these instruments may be lulled into thinking that all of the potential pitfalls have been fully eliminated and believing that, everything one sees on the micrograph is always correct. But, as described in this and the earlier papers, this may not be the case. Care must always be taken when reliable quantitative data are being sought. The first paper in this series discussed some of the issues related to signal generation in the SEM, including instrument calibration, electron beam-sample interactions and the need for physics-based modeling to understand the actual image formation mechanisms to properly interpret SEM images. The second paper has discussed another major issue confronting the microscopist: specimen contamination and methods to eliminate it. The third paper discussed mechanical vibration and stage drift and some useful solutions to mitigate the problems caused by them, and here, in this the fourth contribution, the issues related to specimen "charging" and its mitigation are discussed relative to

Micro-fabric damages in Boom Clay inferred from cryo-BIB-SEM experiment: recent results

NASA Astrophysics Data System (ADS)

Desbois, Guillaume; Schmatz, Joyce; Klaver, Jop; Urai, Janos L.

2017-04-01

The Boom Clay is considered as a potential host rock in Belgium for nuclear waste disposal in a deep geological formation. One of the keys to understand the long-term performance of such a host rock is the fundamental understanding of coupling between microstructural evolution, poromechanical behaviour and the state of hydration of the system. At in situ conditions, Boom Clay is a nearly water-saturated (>94%) clay-rich geomaterial. Subsequently, for measurement of mechanical and transport properties in laboratory, cores of Boom Clay are vacuum-packed in Al-coated-poly-ethylene barrier foil to be best preserved at original hydric state. Because clay microstructures are very sensitive to dehydration, the validity of investigations done on such preserved or/and dried samples is often questionable. Desbois et al. (2009, 2013, 2014) showed the possibility to image fluid-filled porosity in Boom Clay, by using the FIB-cryo-SEM (FIB: Focussed Ion Beam) and FIB-cryo-SEM (BIB: Broad Ion Beam) techniques. However, surprisingly in Desbois et al. (2014), BIB-cryo-SEM experiments on Boom Clay, shown that the majority of the pores were fluid-free, contrasting with result in Desbois et al. (2009). In Desbois et al. (2014), several reasons were discussed to explain such discrepancies. The likely ones are the sealing efficiency of the Al-barrier foil at long term and the volume expansion due to the release of in-situ stress after core extraction, contributing both to dehydration and microfabric damage. This contribution presents the newest results based on cryo-BIB-SEM. Small pieces (30 mm3) of Boom Clay were preserved in liquid nitrogen after the core extraction at the MOL/Dessel Underground Research Laboratory in Belgium. A maximum of ten minutes time span was achieved between opening the core, the sub-sample extraction and the quenching of sub-samples in liquid nitrogen. First results show that all pores visible at cryo-SEM resolution are water saturated. However, water

Endoscopic treatment of large pancreatic fluid collections (PFC) using self-expanding metallic stents (SEMS) - a two-center experience.

PubMed

Chaves, Dalton Marques; Mönkemüller, Klaus; Carneiro, Fred; Medrado, Bruno; Dos Santos, Marcos; Wodak, Stephanie; Reimão, Sílvia; Sakai, Paulo; de Moura, Eduardo

2014-12-01

Background/study aim: During the last several years, endoscopic ultrasound (EUS)-guided pancreatic fluid collections' (PFC) drainage has evolved into the preferred drainage technique. Recently, self-expanding metallic stents (SEMS) have been used as an alternative to double pigtail stents, with the advantage of providing a larger diameter fistula, thereby decreasing the risk of early obstruction and also allowing for direct endoscopic exploration of the cavity. The aim of this study was to evaluate the technical and clinical success, safety, and outcome of patients undergoing EUS-guided drainage of complex PFC using SEMS. The study was conducted at two tertiary hospitals from January 2010 to January 2013. All patients with PFC referred for endoscopic drainage were enrolled in a prospective database. The inclusion criteria were: (1) patients with pseudocysts or walled-off necrosis based on the revised Atlanta classification; (2) symptomatic patients with thick PFC; (3) PFC that persisted more than 6 weeks; and (4) large PFC diameter (≥ 9 cm). The exclusion criteria consisted of coagulation disorders, PFC bleeding or infection, and failure-to-inform written consent. A total of 16 patients (9 females, 7 males; mean age 52.6, range 20 - 82) underwent EUS drainage with SEMS. There were 14 cases of pseudocysts and 2 cases of walled-off necrosis. The etiologies of the PFC were mainly gallstones (8 of 16 patients, 50 %) and alcohol (5 of 16 patients, 31 %). Technical success was achieved in 100 % of the cases. All patients had a complete resolution of the PFC. Transmural EUS-guided drainage of complex PFC using SEMS is feasible, appears safe, and is efficacious. However, the exchange of the UC (uncovered)-SEMS for plastic stents is mandatory within 1 week. Future prospective studies, preferably multicenter studies, comparing SEMS versus traditional plastic stents for the drainage of PFC are warranted.

Photomask quality evaluation using lithography simulation and precision SEM image contour data

NASA Astrophysics Data System (ADS)

Murakawa, Tsutomu; Fukuda, Naoki; Shida, Soichi; Iwai, Toshimichi; Matsumoto, Jun; Nakamura, Takayuki; Hagiwara, Kazuyuki; Matsushita, Shohei; Hara, Daisuke; Adamov, Anthony

2012-11-01

To evaluate photomask quality, the current method uses spatial imaging by optical inspection tools. This technique at 1Xnm node has a resolution limit because small defects will be difficult to extract. To simulate the mask error-enhancement factor (MEEF) influence for aggressive OPC in 1Xnm node, wide FOV contour data and tone information are derived from high precision SEM images. For this purpose we have developed a new contour data extraction algorithm with sub-nanometer accuracy resulting in a wide Field of View (FOV) SEM image: (for example, more than 10um x 10um square). We evaluated MEEF influence of high-end photomask pattern using the wide FOV contour data of "E3630 MVM-SEMTM" and lithography simulator "TrueMaskTM DS" of D2S, Inc. As a result, we can detect the "invisible defect" as the MEEF influence using the wide FOV contour data and lithography simulator.

A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for the Surface of Mars: An Instrument for the Planetary Science Community

NASA Technical Reports Server (NTRS)

Edmunson, J.; Gaskin, J. A.; Danilatos, G.; Doloboff, I. J.; Effinger, M. R.; Harvey, R. P.; Jerman, G. A.; Klein-Schoder, R.; Mackie, W.; Magera, B.;

Image contrast enhancement of Ni/YSZ anode during the slice-and-view process in FIB-SEM.

PubMed

Liu, Shu-Sheng; Takayama, Akiko; Matsumura, Syo; Koyama, Michihisa

2016-03-01

Focused ion beam-scanning electron microscopy (FIB-SEM) is a widely used and easily operational equipment for three-dimensional reconstruction with flexible analysis volume. It has been using successfully and increasingly in the field of solid oxide fuel cell. However, the phase contrast of the SEM images is indistinct in many cases, which will bring difficulties to the image processing. Herein, the phase contrast of a conventional Ni/yttria stabilized zirconia anode is tuned in an FIB-SEM with In-Lens secondary electron (SE) and backscattered electron detectors. Two accessories, tungsten probe and carbon nozzle, are inserted during the observation. The former has no influence on the contrast. When the carbon nozzle is inserted, best and distinct contrast can be obtained by In-Lens SE detector. This method is novel for contrast enhancement. Phase segmentation of the image can be automatically performed. The related mechanism for different images is discussed. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

30 CFR 250.1902 - What must I include in my SEMS program?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 2 2011-07-01 2011-07-01 false What must I include in my SEMS program? 250.1902 Section 250.1902 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT... § 250.1915) (8) Mechanical Integrity (Assurance of Quality and Mechanical Integrity of Critical...

Modelling and analysis of FMS productivity variables by ISM, SEM and GTMA approach

NASA Astrophysics Data System (ADS)

Jain, Vineet; Raj, Tilak

2014-09-01

Productivity has often been cited as a key factor in a flexible manufacturing system (FMS) performance, and actions to increase it are said to improve profitability and the wage earning capacity of employees. Improving productivity is seen as a key issue for survival and success in the long term of a manufacturing system. The purpose of this paper is to make a model and analysis of the productivity variables of FMS. This study was performed by different approaches viz. interpretive structural modelling (ISM), structural equation modelling (SEM), graph theory and matrix approach (GTMA) and a cross-sectional survey within manufacturing firms in India. ISM has been used to develop a model of productivity variables, and then it has been analyzed. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) are powerful statistical techniques. CFA is carried by SEM. EFA is applied to extract the factors in FMS by the statistical package for social sciences (SPSS 20) software and confirming these factors by CFA through analysis of moment structures (AMOS 20) software. The twenty productivity variables are identified through literature and four factors extracted, which involves the productivity of FMS. The four factors are people, quality, machine and flexibility. SEM using AMOS 20 was used to perform the first order four-factor structures. GTMA is a multiple attribute decision making (MADM) methodology used to find intensity/quantification of productivity variables in an organization. The FMS productivity index has purposed to intensify the factors which affect FMS.

FIB/SEM technology and Alzheimer's disease: three-dimensional analysis of human cortical synapses.

PubMed

Blazquez-Llorca, Lidia; Merchán-Pérez, Ángel; Rodríguez, José-Rodrigo; Gascón, Jorge; DeFelipe, Javier

2013-01-01

The quantification and measurement of synapses is a major goal in the study of brain organization in both health and disease. Serial section electron microscopy (EM) is the ideal method since it permits the direct quantification of crucial features such as the number of synapses per unit volume or the distribution and size of synapses. However, a major limitation is that obtaining long series of ultrathin sections is extremely time-consuming and difficult. Consequently, quantitative EM studies are scarce and the most common method employed to estimate synaptic density in the human brain is indirect, by counting at the light microscopic level immunoreactive puncta using synaptic markers. The recent development of automatic EM methods in experimental animals, such as the combination of focused ion beam milling and scanning electron microscopy (FIB/SEM), are opening new avenues. Here we explored the utility of FIB/SEM to examine the cerebral cortex of Alzheimer's disease patients. We found that FIB/SEM is an excellent tool to study in detail the ultrastructure and alterations of the synaptic organization of the human brain. Using this technology, it is possible to reconstruct different types of plaques and the surrounding neuropil to find new aspects of the pathological process associated with the disease, namely; to count the exact number and types of synapses in different regions of the plaques, to study the spatial distribution of synapses, and to analyze the morphology and nature of the various types of dystrophic neurites and amyloid deposits.

Quantification of silver nanoparticle uptake and distribution within individual human macrophages by FIB/SEM slice and view.

PubMed

Guehrs, Erik; Schneider, Michael; Günther, Christian M; Hessing, Piet; Heitz, Karen; Wittke, Doreen; López-Serrano Oliver, Ana; Jakubowski, Norbert; Plendl, Johanna; Eisebitt, Stefan; Haase, Andrea

2017-03-21

Quantification of nanoparticle (NP) uptake in cells or tissues is very important for safety assessment. Often, electron microscopy based approaches are used for this purpose, which allow imaging at very high resolution. However, precise quantification of NP numbers in cells and tissues remains challenging. The aim of this study was to present a novel approach, that combines precise quantification of NPs in individual cells together with high resolution imaging of their intracellular distribution based on focused ion beam/ scanning electron microscopy (FIB/SEM) slice and view approaches. We quantified cellular uptake of 75 nm diameter citrate stabilized silver NPs (Ag 75 Cit) into an individual human macrophage derived from monocytic THP-1 cells using a FIB/SEM slice and view approach. Cells were treated with 10 μg/ml for 24 h. We investigated a single cell and found in total 3138 ± 722 silver NPs inside this cell. Most of the silver NPs were located in large agglomerates, only a few were found in clusters of fewer than five NPs. Furthermore, we cross-checked our results by using inductively coupled plasma mass spectrometry and could confirm the FIB/SEM results. Our approach based on FIB/SEM slice and view is currently the only one that allows the quantification of the absolute dose of silver NPs in individual cells and at the same time to assess their intracellular distribution at high resolution. We therefore propose to use FIB/SEM slice and view to systematically analyse the cellular uptake of various NPs as a function of size, concentration and incubation time.

Measuring topographies from conventional SEM acquisitions.

PubMed

Shi, Qiwei; Roux, Stéphane; Latourte, Félix; Hild, François; Loisnard, Dominique; Brynaert, Nicolas

2018-04-27

The present study extends the stereoscopic imaging principle for estimating the surface topography to two orientations, namely, normal to the electron beam axis and inclined at 70° as suited for EBSD analyses. In spite of the large angle difference, it is shown that the topography can be accurately determined using regularized global Digital Image Correlation. The surface topography is compared to another estimate issued from a 3D FIB-SEM procedure where the sample surface is first covered by a Pt layer, and its initial topography is progressively revealed from successive FIB-milling. These two methods are successfully compared on a 6% strained steel specimen in an in situ mechanical test. This analysis is supplemented by a third approach estimating the change of topography from crystal rotations as measured from successive EBSD images. This last technique ignores plastic deformation, and thus only holds in an elastic regime. For the studied example, despite the large plastic flow, it is shown that crystal rotation already accounts for a significant part of the deformation-induced topography. Copyright © 2018 Elsevier B.V. All rights reserved.

Comparison of ethical judgments exhibited by clients and ethics consultants in Japan

PubMed Central

2014-01-01

Background Healthcare professionals must make decisions for patients based on ethical considerations. However, they rely on clinical ethics consultations (CEC) to review ethical justifications of their decisions. CEC consultants support the cases reviewed and guide medical care. When both healthcare professionals and CEC consultants face ethical problems in medical care, how is their judgment derived? How do medical judgments differ from the ethical considerations of CECs? This study examines CECs in Japan to identify differences in the ethical judgment of clients and CEC consultants. Methods The CEC request and response documents of all 60 cases reviewed across Japan between October 2006 and the end of October 2011 were classified in terms of the presence of decisional capacity in the patient. We conducted a qualitative content analysis of the differences in reasoning between client and CEC consultants. Reasoned judgments were verified in individual cases to classify the similarities or differences of opinion between CEC clients and teams. Results As the result of classification of the decisional capacity and the difference of opinion regarding medical care, the most frequent category was 25 cases (41.7%) of “uncertain decisional capacity,” and 23 cases (38.3%) of “withholding of decision-making.” A chi-square analysis was performed on presence of decisional capacity and agreement in decision-making, yielding a statistically significant difference (p < 0.05). The CEC consultants’ reasoning was based on “patient’s preference was ambiguous,” “validity of family as a surrogate,” “estimation of patient preference,” and “patient’s best interest,” whereas the CEC client’s reasoning was based on “consistent family preference was shown/not shown” and “appropriate therapeutic methods to manage patient safety.” Conclusion Differences in opinions were found in cases classified according to decisional capacity. Furthermore, the

Prescriptive Statements and Educational Practice: What Can Structural Equation Modeling (SEM) Offer?

ERIC Educational Resources Information Center

Martin, Andrew J.

2011-01-01

Longitudinal structural equation modeling (SEM) can be a basis for making prescriptive statements on educational practice and offers yields over "traditional" statistical techniques under the general linear model. The extent to which prescriptive statements can be made will rely on the appropriate accommodation of key elements of research design,…

Quantitative Determination of Noa (Naturally Occurring Asbestos) in Rocks : Comparison Between Pcom and SEM Analysis

NASA Astrophysics Data System (ADS)

Baietto, Oliviero; Amodeo, Francesco; Giorgis, Ilaria; Vitaliti, Martina

2017-04-01

The quantification of NOA (Naturally Occurring Asbestos) in a rock or soil matrix is complex and subject to numerous errors. The purpose of this study is to compare two fundamental methodologies used for the analysis: the first one uses Phase Contrast Optical Microscope (PCOM) while the second one uses Scanning Electron Microscope (SEM). The two methods, although they provide the same result, which is the asbestos mass to total mass ratio, have completely different characteristics and both present pros and cons. The current legislation in Italy involves the use of SEM, DRX, FTIR, PCOM (DM 6/9/94) for the quantification of asbestos in bulk materials and soils and the threshold beyond which the material is considered as hazardous waste is a concentration of asbestos fiber of 1000 mg/kg.(DM 161/2012). The most used technology is the SEM which is the one among these with the better analytical sensitivity.(120mg/Kg DM 6 /9/94) The fundamental differences among the analyses are mainly: - Amount of analyzed sample portion - Representativeness of the sample - Resolution - Analytical precision - Uncertainty of the methodology - Operator errors Due to the problem of quantification of DRX and FTIR (1% DM 6/9/94) our Asbestos Laboratory (DIATI POLITO) since more than twenty years apply the PCOM methodology and in the last years the SEM methodology for quantification of asbestos content. The aim of our research is to compare the results obtained from a PCOM analysis with the results provided by SEM analysis on the base of more than 100 natural samples both from cores (tunnel-boring or explorative-drilling) and from tunnelling excavation . The results obtained show, in most cases, a good correlation between the two techniques. Of particular relevance is the fact that both techniques are reliable for very low quantities of asbestos, even lower than the analytical sensitivity. This work highlights the comparison between the two techniques emphasizing strengths and weaknesses of

Optimization study of direct morphology observation by cold field emission SEM without gold coating.

PubMed

He, Dan; Fu, Cheng; Xue, Zhigang

2018-06-01

Gold coating is a general operation that is generally applied on non-conductive or low conductive materials, during which the morphology of the materials can be examined by scanning electron microscopy (SEM). However, fatal deficiencies in the materials can result in irreversible distortion and damage. The present study directly characterized different low conductive materials such as hydroxyapatite, modified poly(vinylidene fluoride) (PVDF) fiber, and zinc oxide nanopillar by cold field emission scanning electron microscopy (FE-SEM) without a gold coating. According to the characteristics of the low conductive materials, various test conditions, such as different working signal modes, accelerating voltages, electron beam spots, and working distances, were characterized to determine the best morphological observations of each sample. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preliminary SEM Observations on the Surface of Elastomeric Impression Materials after Immersion or Ozone Disinfection

PubMed Central

Prombonas, Anthony; Yannikakis, Stavros; Karampotsos, Thanasis; Katsarou, Martha-Spyridoula; Drakoulis, Nikolaos

2016-01-01

Introduction Surface integrity of dental elastomeric impression materials that are subjected to disinfection is of major importance for the quality of the final prosthetic restorations. Aim The aim of this qualitative Scanning Electronic Microscopy (SEM) study was to reveal the effects of immersion or ozone disinfection on the surface of four dental elastomeric impression materials. Materials and Methods Four dental elastomeric impression material brands were used (two vinyl polysiloxane silicones, one polyether, and one vinyl polyether silicone). Total of 32 specimens were fabricated, eight from each impression material. Specimens were immersion (0.525% sodium hypochlorite solution or 0.3% benzalkonium chloride solution) or ozone disinfected or served as controls and examined with SEM. Results Surface degradation was observed on several speci-mens disinfected with 0.525% sodium hypochlorite solution. Similar wavy-wrinkling surface structures were observed in almost all specimens, when treated either with 0.3% benzalkonium chloride solution or ozone. Conclusion The SEM images obtained from this study revealed that both immersion disinfectants and ozone show similar impression material surface alterations. Ozone seems to be non-inferior as compared to immersion disinfectants, but superior as to environmental protection. PMID:28208993

Analyzing indirect secondary electron contrast of unstained bacteriophage T4 based on SEM images and Monte Carlo simulations

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

Ogura, Toshihiko, E-mail: t-ogura@aist.go.jp

2009-03-06

The indirect secondary electron contrast (ISEC) condition of the scanning electron microscopy (SEM) produces high contrast detection with minimal damage of unstained biological samples mounted under a thin carbon film. The high contrast image is created by a secondary electron signal produced under the carbon film by a low acceleration voltage. Here, we show that ISEC condition is clearly able to detect unstained bacteriophage T4 under a thin carbon film (10-15 nm) by using high-resolution field emission (FE) SEM. The results show that FE-SEM provides higher resolution than thermionic emission SEM. Furthermore, we investigated the scattered electron area within themore » carbon film under ISEC conditions using Monte Carlo simulation. The simulations indicated that the image resolution difference is related to the scattering width in the carbon film and the electron beam spot size. Using ISEC conditions on unstained virus samples would produce low electronic damage, because the electron beam does not directly irradiate the sample. In addition to the routine analysis, this method can be utilized for structural analysis of various biological samples like viruses, bacteria, and protein complexes.« less

SemEHR: A general-purpose semantic search system to surface semantic data from clinical notes for tailored care, trial recruitment, and clinical research.

PubMed

Wu, Honghan; Toti, Giulia; Morley, Katherine I; Ibrahim, Zina M; Folarin, Amos; Jackson, Richard; Kartoglu, Ismail; Agrawal, Asha; Stringer, Clive; Gale, Darren; Gorrell, Genevieve; Roberts, Angus; Broadbent, Matthew; Stewart, Robert; Dobson, Richard J B

2018-05-01

Unlocking the data contained within both structured and unstructured components of electronic health records (EHRs) has the potential to provide a step change in data available for secondary research use, generation of actionable medical insights, hospital management, and trial recruitment. To achieve this, we implemented SemEHR, an open source semantic search and analytics tool for EHRs. SemEHR implements a generic information extraction (IE) and retrieval infrastructure by identifying contextualized mentions of a wide range of biomedical concepts within EHRs. Natural language processing annotations are further assembled at the patient level and extended with EHR-specific knowledge to generate a timeline for each patient. The semantic data are serviced via ontology-based search and analytics interfaces. SemEHR has been deployed at a number of UK hospitals, including the Clinical Record Interactive Search, an anonymized replica of the EHR of the UK South London and Maudsley National Health Service Foundation Trust, one of Europe's largest providers of mental health services. In 2 Clinical Record Interactive Search-based studies, SemEHR achieved 93% (hepatitis C) and 99% (HIV) F-measure results in identifying true positive patients. At King's College Hospital in London, as part of the CogStack program (github.com/cogstack), SemEHR is being used to recruit patients into the UK Department of Health 100 000 Genomes Project (genomicsengland.co.uk). The validation study suggests that the tool can validate previously recruited cases and is very fast at searching phenotypes; time for recruitment criteria checking was reduced from days to minutes. Validated on open intensive care EHR data, Medical Information Mart for Intensive Care III, the vital signs extracted by SemEHR can achieve around 97% accuracy. Results from the multiple case studies demonstrate SemEHR's efficiency: weeks or months of work can be done within hours or minutes in some cases. SemEHR provides a more

Misfit and microleakage of implant-supported crown copings obtained by laser sintering and casting techniques, luted with glass-ionomer, resin cements and acrylic/urethane-based agents.

PubMed

Castillo-Oyagüe, Raquel; Lynch, Christopher D; Turrión, Andrés S; López-Lozano, José F; Torres-Lagares, Daniel; Suárez-García, María-Jesús

2013-01-01

This study evaluated the marginal misfit and microleakage of cement-retained implant-supported crown copings. Single crown structures were constructed with: (1) laser-sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC) and (3) vacuum-cast Ni-Cr-Ti (CN). Samples of each alloy group were randomly luted in standard fashion onto machined titanium abutments using: (1) GC Fuji PLUS (FP); (2) Clearfil Esthetic Cement (CEC); (3) RelyX Unicem 2 Automix (RXU) and (4) DentoTemp (DT) (n=15 each). After 60 days of water ageing, vertical discrepancy was SEM-measured and cement microleakage was scored using a digital microscope. Misfit data were subjected to two-way ANOVA and Student-Newman-Keuls multiple comparisons tests. Kruskal-Wallis and Dunn's tests were run for microleakage analysis (α=0.05). Regardless of the cement type, LS samples exhibited the best fit, whilst CC and CN performed equally well. Despite the framework alloy and manufacturing technique, FP and DT provide comparably better fit and greater microleakage scores than did CEC and RXU, which showed no differences. DMLS of Co-Cr may be a reliable alternative to the casting of base metal alloys to obtain well-fitted implant-supported crowns, although all the groups tested were within the clinically acceptable range of vertical discrepancy. No strong correlations were found between misfit and microleakage. Notwithstanding the framework alloy, definitive resin-modified glass-ionomer (FP) and temporary acrylic/urethane-based (DT) cements demonstrated comparably better marginal fit and greater microleakage scores than did 10-methacryloxydecyl-dihydrogen phosphate-based (CEC) and self-adhesive (RXU) dual-cure resin agents. Copyright © 2012 Elsevier Ltd. All rights reserved.

Applications of Real Space Crystallography in Characterization of Dislocations in Geological Materials in a Scanning Electron Microscope (SEM)

NASA Astrophysics Data System (ADS)

Kaboli, S.; Burnley, P. C.

2017-12-01

Imaging and characterization of defects in crystalline materials is of significant importance in various disciplines including geoscience, materials science, and applied physics. Linear defects such as dislocations and planar defects such as twins and stacking faults, strongly influence many of the properties of crystalline materials and also reflect the conditions and degree of deformation. Dislocations have been conventionally imaged in thin foils in a transmission electron microscope (TEM). Since the development of field emission scanning electron microscopes (FE-SEM) with high gun brightness and small spot size, extensive efforts have been dedicated to the imaging and characterization of dislocations in semi-conductors using electron channeling contrast imaging (ECCI) in the SEM. The obvious advantages of using SEM over TEM include easier and non-destructive sample preparation and a large field of view enabling statistical examination of the density and distribution of dislocations and other defects. In this contribution, we extend this technique to geological materials and introduce the Real Space Crystallography methodology for imaging and complete characterization of dislocations based on bend contour contrast obtained by ECCI in FE-SEM. Bend contours map out the distortion in the crystal lattice across a deformed grain. The contrast of dislocations is maximum in the vicinity of bend contours where crystal planes diffract at small and positive deviations from the Bragg positions (as defined by Bragg's law of electron diffraction). Imaging is performed in a commercial FE-SEM equipped with a standard silicon photodiode backscattered (BSE) detector and an electron backscatter diffraction (EBSD) system for crystal orientation measurements. We demonstrate the practice of this technique in characterization of a number of geological materials in particular quartz, forsterite olivine and corundum, experimentally deformed at high pressure-temperature conditions. This

COMPARATIVE SEM EVALUATION OF THREE SOLVENTS USED IN ENDODONTIC RETREATMENT: AN EX VIVO STUDY

PubMed Central

Scelza, Miriam F. Zaccaro; Coil, Jeffrey M.; Maciel, Ana Carolina de Carvalho; Oliveira, Lílian Rachel L.; Scelza, Pantaleo

2008-01-01

This study compared, by scanning electron microscopy (SEM), the efficacy of three solvents on the removal of filling materials from dentinal tubules during endodontic retreatment. Forty human maxillary canines with straight canals were prepared according to a crown-down technique and enlarged to a#30 apical file size, before obturation with gutta-percha and a zinc-oxide-eugenol based sealer. The samples were stored for 3 months before being randomly assigned to four groups: chloroform (n=10), orange oil (n=10), eucalyptol (n=10) and control (n=10). Solvents were applied to a reservoir created on the coronal root third using Gates Glidden drills. The total time for retreatment using the solvents was 5 minutes per tooth. Following retreatment the roots were split longitudinally for SEM evaluation. SEM images were digitized, analyzed using Image ProPlus 4.5 software, and the number of dentinal tubules free of filling material from the middle and apical thirds was recorded. No significant difference was found among the solvent groups regarding the number of dentinal tubules free of root filling remnants in the middle and apical root thirds (p>0.05). However, the control group had fewer dentinal tubules free of filling material (p<0.05). Under the tested conditions, it may be concluded that there was no significant difference among the solvents used to obtain dentinal tubules free of filling material remnants. PMID:19089285

Maximum Likelihood Dynamic Factor Modeling for Arbitrary "N" and "T" Using SEM

ERIC Educational Resources Information Center

Voelkle, Manuel C.; Oud, Johan H. L.; von Oertzen, Timo; Lindenberger, Ulman

2012-01-01

This article has 3 objectives that build on each other. First, we demonstrate how to obtain maximum likelihood estimates for dynamic factor models (the direct autoregressive factor score model) with arbitrary "T" and "N" by means of structural equation modeling (SEM) and compare the approach to existing methods. Second, we go beyond standard time…

Chapter 24: Strategic Energy Management (SEM) Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

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

Stewart, James

Strategic energy management (SEM) focuses on achieving energy-efficiency improvements through systematic and planned changes in facility operations, maintenance, and behaviors (OM&B) and capital equipment upgrades in large energy-using facilities, including industrial buildings, commercial buildings, and multi-facility organizations such as campuses or communities. Facilities can institute a spectrum of SEM actions, ranging from a simple process for regularly identifying energy-savings actions, to establishing a formal, third-party recognized or certified SEM framework for continuous improvement of energy performance. In general, SEM programs that would be considered part of a utility program will contain a set of energy-reducing goals, principles, and practices emphasizingmore » continuous improvements in energy performance or savings through energy management and an energy management system (EnMS).« less

Validation of cell-free culture using scanning electron microscopy (SEM) and gene expression studies.

PubMed

Yang, R; Elankumaran, Y; Hijjawi, N; Ryan, U

2015-06-01

A cell-free culture system for Cryptosporidium parvum was analysed using scanning electron microscopy (SEM) to characterise life cycle stages and compare gene expression in cell-free culture and cell culture using HCT-8 cells. Cryptosporidium parvum samples were harvested at 2 h, 8 h, 14 h, 26 h, 50 h, 74 h, 98 h, 122 h and 170 h, chemically fixed and specimens were observed using a Zeiss 1555 scanning electron microscope. The presence of sporozoites, trophozoites and type I merozoites were identified by SEM. Gene expression in cell culture and cell-free culture was studied using reverse transcriptase quantitative PCR (RT-qPCR) of the sporozoite surface antigen protein (cp15), the glycoprotein 900 (gp900), the Cryptosporidium oocyst wall protein (COWP) and 18S ribosomal RNA (rRNA) genes in both cell free and conventional cell culture. In cell culture, cp15 expression peaked at 74 h, gp900 expression peaked at 74 h and 98 h and COWP expression peaked at 50 h. In cell-free culture, CP15 expression peaked at 98 h, gp900 expression peaked at 74 h and COWP expression peaked at 122 h. The present study is the first to compare gene expression of C. parvum in cell culture and cell-free culture and to characterise life cycle stages of C. parvum in cell-free culture using SEM. Findings from this study showed that gene expression patterns in cell culture and cell-free culture were similar but in cell-free culture, gene expression was delayed for CP15 and COWP in cell free culture compared with the cell culture system and was lower. Although three life cycle stageswere conclusively identified, improvements in SEM methodology should lead to the detection of more life cycle stages. Copyright © 2015 Elsevier Inc. All rights reserved.

Testing the best method to prepare recent and fossil brachiopod shells for SEM analysis

NASA Astrophysics Data System (ADS)

Crippa, Gaia; Ye, Facheng

2017-04-01

The analysis of shell microstructures by Scanning Electron Microscope (SEM) is a method easily available to most palaeontologists and geochemists. This kind of analysis is a fundamental step in the study of the mineralised parts of marine and terrestrial organisms, and it provides invaluable information in different fields of palaeontology, from the comprehension of evolutionary taxonomy and biomineralisation processes to the screening of shell diagenetic alteration. In precipitating their low-magnesium calcite shells in isotopic equilibrium with ambient seawater, brachiopods are excellent archives of past seawater temperature and ocean chemistry. However, diagenetic processes may alter the original fabric and the original geochemical composition of the shells; the SEM analysis of the microstructure represents one of the most common method used to test fossil shell preservation and eventually exclude diagenetic alteration. Notwithstanding the importance of this analysis, only few and scattered data have been published about the preparation and cleaning of brachiopod shells for SEM analyses Here, we describe several tests performed on recent and fossil brachiopod shells, experimenting new and old methodologies in order to identify a general protocol to better highlight and analyze the shell fabric. Recent taxa include Liothyrella uva and Liothyrella neozelanica, respectively collected from Antarctica and New Zealand; fossil shells are those of Terebratula scillae collected from the lower Pleistocene Stirone River sedimentary succession in Northern Italy. We carried out several tests to check the response of the shell fabric to the resin used to embed the valves before cutting and to different times of exposure to hydrochloric acid; furthermore, as the presence of the organic matrix in recent shells represents the main obstacle to obtaining high quality SEM images, we used bleach and hydrogen peroxide with different concentrations and times of exposure to remove it

Contaminants of emerging concern in fresh leachate from landfills in the conterminous United States

USGS Publications Warehouse

Masoner, Jason R.; Kolpin, Dana W.; Furlong, Edward T.; Cozzarelli, Isabelle M.; Gray, James L.; Schwab, Eric A.

2014-01-01

To better understand the composition of contaminants of emerging concern (CECs) in landfill leachate, fresh leachate from 19 landfills was sampled across the United States during 2011. The sampled network included 12 municipal and 7 private landfills with varying landfill waste compositions, geographic and climatic settings, ages of waste, waste loads, and leachate production. A total of 129 out of 202 CECs were detected during this study, including 62 prescription pharmaceuticals, 23 industrial chemicals, 18 nonprescription pharmaceuticals, 16 household chemicals, 6 steroid hormones, and 4 plant/animal sterols. CECs were detected in every leachate sample, with the total number of detected CECs in samples ranging from 6 to 82 (median = 31). Bisphenol A (BPA), cotinine, and N,N-diethyltoluamide (DEET) were the most frequently detected CECs, being found in 95% of the leachate samples, followed by lidocaine (89%) and camphor (84%). Other frequently detected CECs included benzophenone, naphthalene, and amphetamine, each detected in 79% of the leachate samples. CEC concentrations spanned six orders of magnitude, ranging from ng L−1 to mg L−1. Industrial and household chemicals were measured in the greatest concentrations, composing more than 82% of the total measured CEC concentrations. Maximum concentrations for three household and industrial chemicals, para-cresol (7020000 ng L−1), BPA (6380000 ng L−1), and phenol (1550000 ng L−1), were the largest measured, with these CECs composing 70% of the total measured CEC concentrations. Nonprescription pharmaceuticals represented 12%, plant/animal sterols 4%, prescription pharmaceuticals 1%, and steroid hormones <1% of the total measured CEC concentrations. Leachate from landfills in areas receiving greater amounts of precipitation had greater frequencies of CEC detections and concentrations in leachate than landfills receiving less precipitation.

Novel Paths to Relevance: How Clinical Ethics Committees Promote Ethical Reflection.

PubMed

Magelssen, Morten; Pedersen, Reidar; Førde, Reidun

2016-09-01

How may clinical ethics committees (CECs) inspire ethical reflection among healthcare professionals? How may they deal with organizational ethics issues? In recent years, Norwegian CECs have attempted different activites that stretch or go beyond the standard trio of education, consultation, and policy work. We studied the novel activities of Norwegian CECs by examining annual reports and interviewing CEC members. Through qualitative analysis we identified nine categories of novel CEC activities, which we describe by way of examples. In light of the findings, we argue that some novel working methods may be well suited to promote ethical reflection among clinicians, and that the CEC may be a suitable venue for discussing issues of organizational ethics.

Risk assessment of heavy metals in Vembanad Lake sediments (south-west coast of India), based on acid-volatile sulfide (AVS)-simultaneously extracted metal (SEM) approach.

PubMed

Shyleshchandran, Mohanachandran Nair; Mohan, Mahesh; Ramasamy, Eswara Venkatesaperumal

2018-03-01

Contamination of estuarine system due to heavy metals is a severe issue in tropical countries, especially in India. For the evaluation of the risk due to heavy metals, the current study assessed spatial and temporal variation of acid-volatile sulfide (AVS), simultaneously extracted metal (SEM), and total metal concentration as toxicity indicator of aquatic sediments in Vembanad Lake System (VLS), India. Surface sediment samples collected from 12 locations from the northern portion of VLS for 4 years during different seasons. The results suggest, in post-monsoon season, 91% of the sampling locations possessed high bioavailability of metals and results in toxicity to aquatic biota. The average seasonal distribution of SEM during the period of observations was in the order post-monsoon > pre-monsoon > monsoon (1.76 ± 2.00 > 1.35 ± 0.60 > 0.80 ± 0.54 μmol/g). The concentration of individual metals on ∑SEM are in the order SEM Zn > SEM Cu> SEM Cd ≈ SEM Pb > SEM Hg. Considering annual ΣSEM/AVS ratio, 83% of the sites cross the critical value of 'One,' reveals that active sulfide phase of the sediment for fixing the metals is saturated. The molar ratio (differences between SEM and AVS) and its normalized organic carbon ratio reveals that in the post-monsoon season, about 42% of the sites are in the category of adverse effects are possible. The study suggests the toxicity and mobility of the metals largely depend on the available AVS, and the current situation may pose harm to benthic organisms.

Electron-beam-induced potentials in semiconductors: calculation and measurement with an SEM/SPM hybrid system

NASA Astrophysics Data System (ADS)

Thomas, Ch; Joachimsthaler, I.; Heiderhoff, R.; Balk, L. J.

2004-10-01

In this work electron-beam-induced potentials are analysed theoretically and experimentally for semiconductors. A theoretical model is developed to describe the surface potential distribution produced by an electron beam. The distribution of generated carriers is calculated using semiconductor equations. This distribution causes a local change in surface potential, which is derived with the help of quasi-Fermi energies. The potential distribution is simulated using the model developed and measured with a scanning probe microscope (SPM) built inside a scanning electron microscope (SEM), for different samples, for different beam excitations and for different cantilever voltages of SPM. In the end, some fields of application are shown where material properties can be determined using an SEM/SPM hybrid system.

SEM stereo-section fractography (SSF) observations

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

Zhang, X.J.; Tregoning, R.L.; Armstrong, R.W.

1997-12-31

Cleavage initiation in engineering materials is governed by local microstructural inhomogeneities. These features are often the principal reason for the large scatter evident in fracture toughness measurements which, in extreme cases, can mask the fundamental relationship between cracking resistance and global material properties. The SEM stereo-section fractography (SSF) technique can be used to carefully evaluate these local inhomogeneities through simultaneous observation of both the fracture surface and the underlying microstructure. By sectioning the fracture surface close to the cleavage initiation site (within 10 {micro}m), and perpendicular to both the fracture surface and the precrack front, a direct correspondence between initiationmore » and the local microstructure can be established. Information obtained from this technique can provide quantitative input about important, local microstructural features which can then be used to calibrate or create realistic micromechanical models. A compendium of SSF results is presented herein for cleavage cracking in disparate materials (A533B steel plates, MIL-70S multi-pass weldments, and Ti6A14V forgings), under various testing conditions. In each case, the SSF technique was able to unambiguously identify the dominant, local features which triggered cleavage initiation.« less

Ecosystem classification, Chapter 2

Treesearch

M.J. Robin-Abbott; L.H. Pardo

2011-01-01

The ecosystem classification in this report is based on the ecoregions developed through the Commission for Environmental Cooperation (CEC) for North America (CEC 1997). Only ecosystems that occur in the United States are included. CEC ecoregions are described, with slight modifications, below (CEC 1997) and shown in Figures 2.1 and 2.2. We chose this ecosystem...

XRD and SEM study of alumina silicate porcelain insulator

NASA Astrophysics Data System (ADS)

Duddi, Dharmender; Singh, G. P.; Kalra, Swati; Shekhawat, M. S.; Tak, S. K.

2018-05-01

Higher strength electrical porcelain is a requirement of industry. This will be achieved by a specific composition of raw materials, which is consisted of clays and feldspars. Water absorption, particle size and insulating properties are of special interest now a day. China clay, Ball clay and Quartz are widely used by ceramic industries in Bikaner district of Rajasthan. Sample for present study were prepared by mixing of above clay, feldspar with MnO2, then shrinkage is observed. Bar shaped samples were prepared and heated up to a temperature of about 1185° C to observe shrinkage. For phase study of XRD and SEM are observed.

Microcircuit failure analysis using the SEM. [Scanning Electron Microscopes

NASA Technical Reports Server (NTRS)

Nicolas, D. P.

1974-01-01

The scanning electron microscope adds a new dimension to the knowledge that can be obtained from a failed microcircuit. When used with conventional techniques, SEM assists and clarifies the analysis, but it does not replace light microscopy. The most advantageous features for microcircuit analysis are long working distances and great depth of field. Manufacturer related failure modes of microcircuits are metallization defects, poor bonding, surface and particle contamination, and design and fabrication faults. User related failure modes are caused by abuse, such as overstress. The Physics of Failure Procedure followed by the Astrionics Laboratory in failure analysis is described, which is designed to obtain maximum information available from each step.

Comparative SEM analysis of nine F22 aligner cleaning strategies.

PubMed

Lombardo, Luca; Martini, Marco; Cervinara, Francesca; Spedicato, Giorgio Alfredo; Oliverio, Teresa; Siciliani, Giuseppe

2017-12-01

The orthodontics industry has paid great attention to the aesthetics of orthodontic appliances, seeking to make them as invisible as possible. There are several advantages to clear aligner systems, including aesthetics, comfort, chairside time reduction, and the fact that they can be removed for meals and oral hygiene procedures. Five patients were each given a series of F22 aligners, each to be worn for 14 days and nights, with the exception of meal and brushing times. Patients were instructed to clean each aligner using a prescribed strategy, and sections of the used aligners were observed under SEM. One grey-scale SEM image was saved per aligner in JPEG format with an 8-bit colour depth, and a total of 45 measurements on the grey scale ("Value" variable) were made. This dataset was analysed statistically via repeated measures ANOVA to determine the effect of each of the nine cleaning strategies in each of the five patients. A statistically significant difference in the efficacy of the cleaning strategies was detected. Specifically, rinsing with water alone was significantly less efficacious, and a combination of cationic detergent solution and ultrasonication was significantly more efficacious than the other methods (p < 0.05). Of the nine cleaning strategies examined, only that involving 5 min of ultrasonication at 42 k Hz combined with a 0.3% germicidal cationic detergent was observed to be statistically effective at removing the bacterial biofilm from the surface of F22 aligners.

Improvement in the Characterization of the 2099 Al-Li Alloy by FE-SEM

NASA Astrophysics Data System (ADS)

Brodusch, Nicolas; Trudeau, Michel L.; Michaud, Pierre; Brochu, Mathieu; Rodrigue, Lisa; Boselli, Julien; Gauvin, Raynald

This paper describes how state-of-the-art Field-Emission Scanning Electron Microscopy (FE-SEM) can contribute to the characterization of the 2099 aluminum-lithium alloy, and metallic alloys in general. Investigations were carried out on bulk and thinned samples. BSE imaging at 3kV and STEM imaging at 30kV along with highly efficient microanalysis permitted to correlate experimental and expected structures. Although our results confirm previous studies, this work points out possible substitutions of Mg and Zn with Li, Al and Cu in the T1 precipitates. Zinc and magnesium are also present in "rice grain" shaped precipitates at the grain boundaries. The versatility of the FE-SEM is highlighted in that it can provide information at the macro and micro scales with relevant details. Its ability to probe the distribution of precipitates from nano-to micro-sizes throughout the matrix makes Field-Emission Scanning Electron Microscopy a suitable technique for the characterization of metallic alloys.

Circulating endothelial cells as marker of endothelial damage in male hypogonadism.

PubMed

Milardi, Domenico; Grande, Giuseppe; Giampietro, Antonella; Vendittelli, Francesca; Palumbo, Sara; Tartaglione, Linda; Marana, Riccardo; Pontecorvi, Alfredo; de Marinis, Laura; Zuppi, Cecilia; Capoluongo, Ettore

2012-01-01

Testosterone deficiency has become a frequently diagnosed condition in today's society affected by epidemic obesity, and is associated with cardiovascular risk. Recent studies have established the importance of altered vascular endothelium function in cardiovascular disease. The damage to the endothelium might also cause endothelial cell detachment, resulting in increased numbers of circulating endothelial cells (CEC) within the bloodstream. To evaluate whether hypogonadism could modify CEC count in peripheral bloodstream, we investigated peripheral blood CEC count using the CellSearch System, a semiautomatic method to accurately and reliably enumerate CECs, which are sorted based on a CD146(+), CD105(+), DAPI(+), CD45(-) phenotype, in a population of 20 patients with hypogonadism. The control group comprised 10 age- and sex-matched healthy participants. CEC count per milliliter was significantly increased in patients with hypogonadism vs the control group. In the group with hypogonadism, an inverse exponential correlation was present between testosterone levels and CEC count per milliliter. A direct linear correlation was present between waist circumference and CECs and between body mass index and CECs. The regression analysis showed that testosterone was the significant independent determinant of CECs. Our results underline that male hypogonadism is associated with endothelial dysfunction. The correlation between CEC and waist circumference underlines that visceral obesity may be synergically implicated in this regulation. Future studies are required to unveil the mechanisms involved in the pathogenesis of testosterone-induced endothelial disfunction, which may provide novel therapeutic targets to be incorporated in the management of hypogonadism.

[A Case of Removable Self-Expandable Metallic Stent(SEMS)Placement for Gastric Tube Stenosis after Esophageal Cancer Resection].

PubMed

Yoshikawa, Yukihiro; Yoshikawa, Masato; Kawabata, Ryohei; Yoshida, Yuta; Kawada, Masahiro; Yasuyama, Akinobu; Watase, Chikashi; Koga, Chikato; Hitora, Toshiki; Murakami, Masahiro; Hirota, Masaki; Ikenaga, Masakazu; Shimizu, Junzo; Hasegawa, Junichi

2015-11-01

A 68-year-old man underwent esophagectomy for early esophageal cancer. Postoperative upper gastrointestinal series and esophagogastroduodenoscopy showed gastric tube stenosis. To improve passage, a removable self-expandable metallic stent (SEMS) was placed across the stenotic lesion. Two weeks later, the stent was removed, and passage through the gastric tube improved. The patient has no symptoms of stenosis. A removable SEMS could be an option for the treatment of gastric tube stenosis after esophagectomy.

Measurement invariance via multigroup SEM: Issues and solutions with chi-square-difference tests.

PubMed

Yuan, Ke-Hai; Chan, Wai

2016-09-01

Multigroup structural equation modeling (SEM) plays a key role in studying measurement invariance and in group comparison. When population covariance matrices are deemed not equal across groups, the next step to substantiate measurement invariance is to see whether the sample covariance matrices in all the groups can be adequately fitted by the same factor model, called configural invariance. After configural invariance is established, cross-group equalities of factor loadings, error variances, and factor variances-covariances are then examined in sequence. With mean structures, cross-group equalities of intercepts and factor means are also examined. The established rule is that if the statistic at the current model is not significant at the level of .05, one then moves on to testing the next more restricted model using a chi-square-difference statistic. This article argues that such an established rule is unable to control either Type I or Type II errors. Analysis, an example, and Monte Carlo results show why and how chi-square-difference tests are easily misused. The fundamental issue is that chi-square-difference tests are developed under the assumption that the base model is sufficiently close to the population, and a nonsignificant chi-square statistic tells little about how good the model is. To overcome this issue, this article further proposes that null hypothesis testing in multigroup SEM be replaced by equivalence testing, which allows researchers to effectively control the size of misspecification before moving on to testing a more restricted model. R code is also provided to facilitate the applications of equivalence testing for multigroup SEM. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

SEM evaluation of human gingival fibroblasts growth onto CAD/CAM zirconia and veneering ceramic for zirconia

PubMed Central

Zizzari, Vincenzo; Borelli, Bruna; De Colli, Marianna; Tumedei, Margherita; Di Iorio, Donato; Zara, Susi; Sorrentino, Roberto; Cataldi, Amelia; Gherlone, Enrico Felice; Zarone, Fernando; Tetè, Stefano

2013-01-01

Summary Aim To evaluate the growth of Human Gingival Fibroblasts (HGFs) cultured onto sample discs of CAD/CAM zirconia and veneering ceramic for zirconia by means of Scanning Electron Microscope (SEM) analysis at different experimental times. Methods A total of 26 experimental discs, divided into 2 groups, were used: Group A) CAD/CAM zirconia (3Y-TZP) discs (n=13); Group B) veneering ceramic for zirconia discs (n=13). HGFs were obtained from human gingival biopsies, isolated and placed in culture plates. Subsequently, cells were seeded on experimental discs at 7,5×103/cm2 concentration and cultured for a total of 7 days. Discs were processed for SEM observation at 3h, 24h, 72h and 7 days. Results In Group A, after 3h, HGFs were adherent to the surface and showed a flattened profile. The disc surface covered by HGFs resulted to be wider in Group A than in Group B samples. At SEM observation, after 24h and 72h, differences in cell attachment were slightly noticeable between the groups, with an evident flattening of HGFs on both surfaces. All differences between Group A and group B became less significant after 7 days of culture in vitro. Conclusions SEM analysis of HGFs showed differences in terms of cell adhesion and proliferation, especially in the early hours of culture. Results showed a better adhesion and cell growth in Group A than in Group B, especially up to 72h in vitro. Differences decreased after 7 days, probably because of the rougher surface of CAD/CAM zirconia, promoting better cell adhesion, compared to the smoother surface of veneering ceramic. PMID:24611089

SEM Imaging and Chemical Analysis of Aerosol Particles from Surface and Hi-altitudes in New Jersey.

NASA Astrophysics Data System (ADS)

Bandamede, M.; Boaggio, K.; Bancroft, L.; Hurler, K.; Magee, N. B.

2016-12-01

We report on Scanning Electron Microscopy analysis of aerosol particle morphology and chemistry. The work includes the first comparative SEM analysis of aerosol particles captured by balloon at high altitude. The particles were acquired in an urban/suburban environment in central New-Jersey. Particles were sampled from near the surface using ambient air filtration and at high-altitudes using a novel balloon-borne instrument (ICE-Ball, see abstract by K. Boaggio). Particle images and 3D geometry are acquired by a Hitachi SU-5000 SEM, with resolution to approximately 3 nm. Elemental analysis on particles is provided by Energy Dispersive X-Ray Spectroscopy (EDS, EDAX, Inc.). Uncoated imaging is conducted in low vacuum within the variable-pressure SEM, which provides improved detection and analysis of light-element compositions including Carbon. Preliminary results suggest that some similar particle types and chemical species are sampled at both surface and high-altitude. However, as expected, particle morphologies, concentrations, chemistry, and apparent origin vary significantly at different altitudes and under different atmospheric flow regimes. Improved characterization of high-altitude aerosol particles, and differences from surface particulate composition, may advance inputs for atmospheric cloud and radiation models.

Modification of Montmorillonite with Cetyl Trimethylammonium Bromide and Tetra Ethyl Ortho Silicate

NASA Astrophysics Data System (ADS)

Widjonarko, D. M.; Mayasari, O. D.; Wahyuningsih, S.; Nugrahaningtyas, K. D.

2018-03-01

Modification of montmorillonite (MMt) with cetyltrimethylammonium bromide (CTAB) and tetraethyl ortosilicate (TEOS) has been done. The aim of the research is to study the effect of TEOS and CTAB into MMt. This research is a preliminary step to invent material that can be modified with other functional materials. The study was conducted by recting TEOS with MMt and varying CTAB concentration on MMt previously modified with TEOS. The TEOS concentration was 4.72 M while CTAB concentration was 0.25; 0.5; 2; 3.5; and 5 mmol/g in MMt which has been reacted with TEOS. Material characterization was done by X-Ray Diffraction (XRD), Fourrier Transform Infra-Red Spectrophotometer (FTIR) and Scanning Electron Microscope (SEM). Cation exchange capacity (CEC) of materials was analyzed by titration method. The results show that TEOS and CTAB successfully modified. TEOS adsorbed onto MMt. It was identified from increased basal spacing, specific group and also by its elemental composition, originally having basal spacing 16 Å. After modification with CTAB, basal spacing increased to 28.45 Å or 77.64%. This indicates that CTAB is intercalated within the MMt layers. The CEC of new material is 0.93 meq/g, increase from 0.83 meq/g.

A Sandwich-Type Standard Error Estimator of SEM Models with Multivariate Time Series

ERIC Educational Resources Information Center

Zhang, Guangjian; Chow, Sy-Miin; Ong, Anthony D.

2011-01-01

Structural equation models are increasingly used as a modeling tool for multivariate time series data in the social and behavioral sciences. Standard error estimators of SEM models, originally developed for independent data, require modifications to accommodate the fact that time series data are inherently dependent. In this article, we extend a…

Human bloodstains on bone artefacts: an SEM intra- and inter-sample comparative study using ratite bird tibiotarsus.

PubMed

Hortolà, Policarp

2016-11-01

Apart from their forensic significance in crime investigation, human bloodstains have an anthropological interest due to their occurrence on certain traditional weapons and ritual objects. Previously, a guiding study of erythrocytes in experimental samples including domestic sheep (Ovis aries) tibia was carried out using a scanning electron microscope (SEM). Here, a comparative SEM study to reveal the potential differences in bloodstain surface morphology as a function of intra-sample (smear region) and inter-sample (individual smear, smearing mechanism, bone origin) parameters is reported. A fragment of emu (Dromaius novaehollandiae) tibiotarsus was smeared with an adult man's peripheral blood. After air-drying and storing indoors, the boundary and neighbouring inner areas of the three individual bloodstains obtained were examined via secondary electrons in a variable-pressure SEM working in low-vacuum mode. As a whole, desiccation microcracks were present, the limits between the smear and the substrate appeared poorly defined, and no erythrocyte negative replicas were observed in the examined areas. In addition, a putative fibrin network, more or less embedded in the dried plasma matrix, was observed in the smears' boundary. Regarding the smear region in sliding smears, the periphery and boundary revealed to be different, while the head and tail were similar. Considering individual sliding smears, they had similar characteristics. Relating to the smear region as a function of the smearing mechanism, the periphery was different whether sliding or touching, while the boundary was similar in sliding and touching smears. Concerning the smear region as a function of the bone origin, the periphery revealed to be similar in both ratite and mammalian bone, while the boundary did different in ratite and mammalian bone. The results of this study show that SEM examination can be used fruitfully to detect bloodstains on ratite bone. Combined with previous SEM results in

Extraembryonic origin of circulating endothelial cells.

PubMed

Pardanaud, Luc; Eichmann, Anne

2011-01-01

Circulating endothelial cells (CEC) are contained in the bone marrow and peripheral blood of adult humans and participate to the revascularization of ischemic tissues. These cells represent attractive targets for cell or gene therapy aimed at improving ischemic revascularization or inhibition of tumor angiogenesis. The embryonic origin of CEC has not been addressed previously. Here we use quail-chick chimeras to study CEC origin and participation to the developing vasculature. CEC are traced with different markers, in particular the QH1 antibody recognizing only quail endothelial cells. Using yolk-sac chimeras, where quail embryos are grafted onto chick yolk sacs and vice-versa, we show that CEC are generated in the yolk sac. These cells are mobilized during wound healing, demonstrating their participation to angiogenic repair processes. Furthermore, we found that the allantois is also able to give rise to CEC in situ. In contrast to the yolk sac and allantois, the embryo proper does not produce CEC. Our results show that CEC exclusively originate from extra-embryonic territories made with splanchnopleural mesoderm and endoderm, while definitive hematopoietic stem cells and endothelial cells are of intra-embryonic origin.

SEM Microanalysis of Particles: Concerns and Suggestions

NASA Astrophysics Data System (ADS)

Fournelle, J.

2008-12-01

The scanning electron microscope (SEM) is well suited to examine and characterize small (i.e. <10 micron) particles. Particles can be imaged and sizes and shapes determined. With energy dispersive x-ray spectrometers (EDS), chemical compositions can be determined quickly. Despite the ease in acquiring x-ray spectra and chemical compositions, there are potentially major sources of error to be recognized. Problems with EDS analyses of small particles: Qualitive estimates of composition (e.g. stating that Si>Al>Ca>Fe plus O) are easy. However, to be able to have confidence that a chemical composition is accurate, several issues should be examined. (1) Particle Mass Effect: Is the accelerating voltage appropriate for the specimen size? Are all the incident electrons remaining inside the particle, and not traveling out of the sample side or bottom? (2) Particle Absorption Effect: What is the geometric relationship of the beam impact point to the x-ray detector? The x-ray intensity will vary by significant amounts for the same material if the grains are irregular and the path out of the sample in the direction of the detector is longer or shorter. (3) Particle Fluorescence Effect: This is generally a smaller error, but should be considered: for small particles, using large standards, there will be a few % less x-rays generated in a small particle relative to one of the same composition and 50-100 times larger. Also, if the sample sits on a grid of a particular composition (e.g. Si wafer) potentially several % of Si could appear in the analysis. (4) In a increasing number of laboratories, with environmental or variable pressure SEMs, the Gas Skirt Effect is operating against you: here the incident electron beam scatters in the gas in the chamber, with less electrons impacting the target spot and some others hitting grains 100s of microns away, producing spectra that could be faulty. (5) Inclusion of measured oxygen: if the measured oxygen x-ray counts are utilized

Ribonuclease 5 facilitates corneal endothelial wound healing via activation of PI3-kinase/Akt pathway

PubMed Central

Kim, Kyoung Woo; Park, Soo Hyun; Lee, Soo Jin; Kim, Jae Chan

2016-01-01

To maintain corneal transparency, corneal endothelial cells (CECs) exert a pump function against aqueous inflow. However, human CECs are arrested in the G1-phase and non-proliferative in vivo. Thus, treatment of corneal endothelial decompensation is limited to corneal transplantation, and grafts are vulnerable to immune rejection. Here, we show that ribonuclease (RNase) 5 is more highly expressed in normal human CECs compared to decompensated tissues. Furthermore, RNase 5 up-regulated survival of CECs and accelerated corneal endothelial wound healing in an in vitro wound of human CECs and an in vivo cryo-damaged rabbit model. RNase 5 treatment rapidly induced accumulation of cytoplasmic RNase 5 into the nucleus, and activated PI3-kinase/Akt pathway in human CECs. Moreover, inhibition of nuclear translocation of RNase 5 using neomycin reversed RNase 5-induced Akt activation. As a potential strategy for proliferation enhancement, RNase 5 increased the population of 5-bromo-2′-deoxyuridine (BrdU)-incorporated proliferating CECs with concomitant PI3-kinase/Akt activation, especially in CECs deprived of contact-inhibition. Specifically, RNase 5 suppressed p27 and up-regulated cyclin D1, D3, and E by activating PI3-kinase/Akt in CECs to initiate cell cycle progression. Together, our data indicate that RNase 5 facilitates corneal endothelial wound healing, and identify RNase 5 as a novel target for therapeutic exploitation. PMID:27526633

Mechanical and SEM analysis of artificial comet nucleus samples

NASA Technical Reports Server (NTRS)

Thiel, K.; Kochan, H.; Roessler, K.; Gruen, E.; Schwehm, G.; Hellmann, H.; Hsiung, P.; Koelzer, G.

1989-01-01

Since 1987 experiments dealing with comet nucleus phenomena have been carried out in the DFVLR space simulation chambers. The main objective of these experiments is a better understanding of thermal behavior, surface phenomena and especially the gas dust interaction. As a function of different sample compositions and exposure to solar irradiation (xenon-bulbs) crusts of different hardness and thickness were measured. The measuring device consists of a motor driven pressure foot (5 mm diameter), which is pressed into the sample. The applied compressive force is electronically monitored. The microstructure of the crust and dust residuals is investigated by scanning electron microscopy (SEM) techniques. Stress-depth profiles of an unirradiated and an irradiated model comet are given.

Impact of a 1-year lifestyle modification program on cholesterol efflux capacities in men with abdominal obesity and dyslipidemia.

PubMed

Boyer, Marjorie; Mitchell, Patricia L; Poirier, Dr Paul; Alméras, Natalie; Tremblay, Angelo; Bergeron, Jean; Despres, Jean-Pierre; Arsenault, Benoit J

2018-06-05

Cholesterol efflux capacities (CECs) are negatively associated with cardiovascular disease risk, irrespective of plasma high-density lipoprotein (HDL) cholesterol levels. Whether interventions targeting lifestyle improve HDL-CECs is unknown. Our objective was to determine whether improving dietary quality and increasing physical activity levels improves HDL-CECs in abdominally obese men with dyslipidemia. Our study sample included men (488.5 years) with an elevated waist circumference ({greater than or equal to}90 cm) associated with dyslipidemia (triglycerides {greater than or equal to}1.69 and/or HDL cholesterol <1.03 mmol/l); 113 men completed a 1-year intervention, consisting of a healthy eating and physical activity/exercise program and 32 were included in a control group. An oral lipid tolerance test (OLTT) was performed in a subsample of 28 men who completed the intervention and blood was collected every 2 hours during 8 hours. HDL-CECs were measured using 3 H cholesterol labeled J774 macrophages and HepG2 hepatocytes. The lifestyle modification program led to an overall improvement in the cardiometabolic risk profile, increases in J774-HDL-CEC by 14.1% (+0.881.09%, p<0.0001), HepG2-HDL-CEC by 3.4% (+0.170.75%, p=0.01), HDL-C and apolipoprotein A-1 levels (13.5%, p<0.0001 and 14.9%, p<0.0001, respectively). J774-HDL-CECs and HepG2-HDL-CECs did not change in the control group. The best predictor for changes in HDL-CEC was Apo A1 level. The lifestyle modification program also improved HDL-CECs response in postprandial lipemia during an OLTT. HDL-CEC did not change during the OLTT. Our results suggest that increasing physical activity levels and improving diet quality can have a positive impact on both HDL quantity and quality in abdominally obese men with dyslipidemia.

Propagation of human corneal endothelial cells: a novel dual media approach.

PubMed

Peh, Gary S L; Chng, Zhenzhi; Ang, Heng-Pei; Cheng, Terence Y D; Adnan, Khadijah; Seah, Xin-Yi; George, Benjamin L; Toh, Kah-Peng; Tan, Donald T; Yam, Gary H F; Colman, Alan; Mehta, Jodhbir S

2015-01-01

Corneal endothelium-associated corneal blindness is the most common indication for corneal transplantation. Restorative corneal transplant surgery is the only option to reverse the blindness, but a global shortage of donor material remains an issue. There are immense clinical interests in the development of alternative treatment strategies to alleviate current reliance on donor materials. For such endeavors, ex vivo propagation of human corneal endothelial cells (hCECs) is required, but current methodology lacks consistency, with expanded hCECs losing cellular morphology to a mesenchymal-like transformation. In this study, we describe a novel dual media culture approach for the in vitro expansion of primary hCECs. Initial characterization included analysis of growth dynamics of hCECs grown in either proliferative (M4) or maintenance (M5) medium. Subsequent comparisons were performed on isolated hCECs cultured in M4 alone against cells expanded using the dual media approach. Further characterizations were performed using immunocytochemistry, quantitative real-time PCR, and gene expression microarray. At the third passage, results showed that hCECs propagated using the dual media approach were homogeneous in appearance, retained their unique polygonal cellular morphology, and expressed higher levels of corneal endothelium-associated markers in comparison to hCECs cultured in M4 alone, which were heterogeneous and fibroblastic in appearance. Finally, for hCECs cultured using the dual media approach, global gene expression and pathway analysis between confluent hCECs before and after 7-day exposure to M5 exhibited differential gene expression associated predominately with cell proliferation and wound healing. These findings showed that the propagation of primary hCECs using the novel dual media approach presented in this study is a consistent method to obtain bona fide hCECs. This, in turn, will elicit greater confidence in facilitating downstream development of

Circulating Endothelial Cells in Patients with Heart Failure and Left Ventricular Dysfunction

PubMed Central

Martínez-Sales, Vicenta; Sánchez-Lázaro, Ignacio; Vila, Virtudes; Almenar, Luis; Contreras, Teresa; Reganon, Edelmiro

2011-01-01

Introduction and Aims: Acute and chronic heart failure may manifest different degrees of endothelial damage and angiogenesis. Circulating endothelial cells (CEC) have been identified as marker of vascular damage. The aim of our study was to evaluate the evolution of the CEC at different stages of patients with heart failure. We also investigated a potential correlation between CEC and markers of vascular damage and angiogenesis. Methods: We studied 32 heart failure patients at hospital admission (acute phase) and at revision after 3 months (stable phase) and 32 controls. Circulating markers of endothelial damage (CEC; von Willebrand factor, vWF and soluble E-selectin, sEsel) and angiogenesis (vascular endothelial growth factor, VEGF and thrombospondin-1) were quantified. Results: Levels of CEC, vWF, sEsel and VEGF are significantly higher in heart failure patients than in controls. Levels of CEC (36.9 ± 15.3 vs. 21.5 ± 10.0 cells/ml; p < 0.001), vWF (325 ± 101 vs. 231 ± 82%; p < 0.001) and VEGF (26.3 ± 15.2 vs. 21.9 ± 11.9 ng/ml; p < 0.001) are significantly higher in the acute phase than in the stable phase of heart failure. CEC levels correlate with vWF and VEGF. Results show than 100% of patients in acute phase and 37.5% in stable phase have levels of CEC higher than the 99th percentile of the distribution of controls (16 cells/ml). Therefore, increases in CEC represent a relative risk of 9.5 for heart failure patients suffering from acute phase. Conclusions: CEC, in addition to being elevated in heart failure, correlate with vWF levels, providing further support for CEC as markers of endothelial damage. Levels of CEC are associated with the acute phase of heart failure and could be used as a marker of the worsening in heart failure. PMID:21897001

30 CFR 250.1920 - What are the auditing requirements for my SEMS program?

Code of Federal Regulations, 2012 CFR

2012-07-01

... designated and qualified personnel according to the requirements of this subpart and API RP 75, Section 12... thirteen elements of your SEMS program to evaluate compliance with the requirements of this subpart and API... audit plan and procedures must meet or exceed all of the recommendations included in API RP 75 section...

Three-dimensional intracellular structure of a whole rice mesophyll cell observed with FIB-SEM.

PubMed

Oi, Takao; Enomoto, Sakiko; Nakao, Tomoyo; Arai, Shigeo; Yamane, Koji; Taniguchi, Mitsutaka

2017-07-01

Ultrathin sections of rice leaf blades observed two-dimensionally using a transmission electron microscope (TEM) show that the chlorenchyma is composed of lobed mesophyll cells, with intricate cell boundaries, and lined with chloroplasts. The lobed cell shape and chloroplast positioning are believed to enhance the area available for the gas exchange surface for photosynthesis in rice leaves. However, a cell image revealing the three-dimensional (3-D) ultrastructure of rice mesophyll cells has not been visualized. In this study, a whole rice mesophyll cell was observed using a focused ion beam scanning electron microscope (FIB-SEM), which provides many serial sections automatically, rapidly and correctly, thereby enabling 3-D cell structure reconstruction. Rice leaf blades were fixed chemically using the method for conventional TEM observation, embedded in resin and subsequently set in the FIB-SEM chamber. Specimen blocks were sectioned transversely using the FIB, and block-face images were captured using the SEM. The sectioning and imaging were repeated overnight for 200-500 slices (each 50 nm thick). The resultant large-volume image stacks ( x = 25 μm, y = 25 μm, z = 10-25 μm) contained one or two whole mesophyll cells. The 3-D models of whole mesophyll cells were reconstructed using image processing software. The reconstructed cell models were discoid shaped with several lobes around the cell periphery. The cell shape increased the surface area, and the ratio of surface area to volume was twice that of a cylinder having the same volume. The chloroplasts occupied half the cell volume and spread as sheets along the cell lobes, covering most of the inner cell surface, with adjacent chloroplasts in close contact with each other. Cellular and sub-cellular ultrastructures of a whole mesophyll cell in a rice leaf blade are demonstrated three-dimensionally using a FIB-SEM. The 3-D models and numerical information support the hypothesis that rice mesophyll

Deep learning and shapes similarity for joint segmentation and tracing single neurons in SEM images

NASA Astrophysics Data System (ADS)

Rao, Qiang; Xiao, Chi; Han, Hua; Chen, Xi; Shen, Lijun; Xie, Qiwei

2017-02-01

Extracting the structure of single neurons is critical for understanding how they function within the neural circuits. Recent developments in microscopy techniques, and the widely recognized need for openness and standardization provide a community resource for automated reconstruction of dendritic and axonal morphology of single neurons. In order to look into the fine structure of neurons, we use the Automated Tape-collecting Ultra Microtome Scanning Electron Microscopy (ATUM-SEM) to get images sequence of serial sections of animal brain tissue that densely packed with neurons. Different from other neuron reconstruction method, we propose a method that enhances the SEM images by detecting the neuronal membranes with deep convolutional neural network (DCNN) and segments single neurons by active contour with group shape similarity. We joint the segmentation and tracing together and they interact with each other by alternate iteration that tracing aids the selection of candidate region patch for active contour segmentation while the segmentation provides the neuron geometrical features which improve the robustness of tracing. The tracing model mainly relies on the neuron geometrical features and is updated after neuron being segmented on the every next section. Our method enables the reconstruction of neurons of the drosophila mushroom body which is cut to serial sections and imaged under SEM. Our method provides an elementary step for the whole reconstruction of neuronal networks.

Qualitative and quantitative interpretation of SEM image using digital image processing.

PubMed

Saladra, Dawid; Kopernik, Magdalena

2016-10-01

The aim of the this study is improvement of qualitative and quantitative analysis of scanning electron microscope micrographs by development of computer program, which enables automatic crack analysis of scanning electron microscopy (SEM) micrographs. Micromechanical tests of pneumatic ventricular assist devices result in a large number of micrographs. Therefore, the analysis must be automatic. Tests for athrombogenic titanium nitride/gold coatings deposited on polymeric substrates (Bionate II) are performed. These tests include microshear, microtension and fatigue analysis. Anisotropic surface defects observed in the SEM micrographs require support for qualitative and quantitative interpretation. Improvement of qualitative analysis of scanning electron microscope images was achieved by a set of computational tools that includes binarization, simplified expanding, expanding, simple image statistic thresholding, the filters Laplacian 1, and Laplacian 2, Otsu and reverse binarization. Several modifications of the known image processing techniques and combinations of the selected image processing techniques were applied. The introduced quantitative analysis of digital scanning electron microscope images enables computation of stereological parameters such as area, crack angle, crack length, and total crack length per unit area. This study also compares the functionality of the developed computer program of digital image processing with existing applications. The described pre- and postprocessing may be helpful in scanning electron microscopy and transmission electron microscopy surface investigations. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

78 FR 50079 - Information Collection Activities: Safety and Environmental Management Systems (SEMS); Proposed...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-16

... DEPARTMENT OF THE INTERIOR Bureau of Safety and Environmental Enforcement [Docket ID BSEE-2013-0005; OMB Control Number 1014-0017: 134E1700D2 EEEE500000 ET1SF0000.DAQ000] Information Collection Activities: Safety and Environmental Management Systems (SEMS); Proposed Collection; Comment Request Correction In notice document 2013-19416 appearing o...

Allowable SEM noise for unbiased LER measurement

NASA Astrophysics Data System (ADS)

Papavieros, George; Constantoudis, Vassilios; Gogolides, Evangelos

2018-03-01

Recently, a novel method for the calculation of unbiased Line Edge Roughness based on Power Spectral Density analysis has been proposed. In this paper first an alternative method is discussed and investigated, utilizing the Height-Height Correlation Function (HHCF) of edges. The HHCF-based method enables the unbiased determination of the whole triplet of LER parameters including besides rms the correlation length and roughness exponent. The key of both methods is the sensitivity of PSD and HHCF on noise at high frequencies and short distance respectively. Secondly, we elaborate a testbed of synthesized SEM images with controlled LER and noise to justify the effectiveness of the proposed unbiased methods. Our main objective is to find out the boundaries of the method in respect to noise levels and roughness characteristics, for which the method remains reliable, i.e the maximum amount of noise allowed, for which the output results cope with the controllable known inputs. At the same time, we will also set the extremes of roughness parameters for which the methods hold their accuracy.

Improving microstructural quantification in FIB/SEM nanotomography.

PubMed

Taillon, Joshua A; Pellegrinelli, Christopher; Huang, Yi-Lin; Wachsman, Eric D; Salamanca-Riba, Lourdes G

2018-01-01

FIB/SEM nanotomography (FIB-nt) is a powerful technique for the determination and quantification of the three-dimensional microstructure in subsurface features. Often times, the microstructure of a sample is the ultimate determiner of the overall performance of a system, and a detailed understanding of its properties is crucial in advancing the materials engineering of a resulting device. While the FIB-nt technique has developed significantly in the 15 years since its introduction, advanced nanotomographic analysis is still far from routine, and a number of challenges remain in data acquisition and post-processing. In this work, we present a number of techniques to improve the quality of the acquired data, together with easy-to-implement methods to obtain "advanced" microstructural quantifications. The techniques are applied to a solid oxide fuel cell cathode of interest to the electrochemistry community, but the methodologies are easily adaptable to a wide range of material systems. Finally, results from an analyzed sample are presented as a practical example of how these techniques can be implemented. Copyright © 2017 Elsevier B.V. All rights reserved.

Development and application of loop-mediated isothermal amplification methods targeting the seM gene for detection of Streptococcus equi subsp. equi.

PubMed

Hobo, Seiji; Niwa, Hidekazu; Oku, Kazuomi

2012-03-01

Loop-mediated isothermal amplification (LAMP) constitutes a potentially valuable diagnostic tool for rapid diagnosis of contagious diseases. In this study, we developed a novel LAMP method (seM-LAMP) to detect the seM gene of Streptococcus equi subsp. equi (S. equi), the causative agent of strangles in equids. The seM-LAMP successfully amplified the target sequence of the seM gene at 63°C within 60 min. The sensitivity of the seM-LAMP was slightly lower than the 2nd reaction of the seM semi-nested PCR. To evaluate the species specificity of the seM-LAMP, we tested 100 S. equi and 189 non-S. equi strains. Significant amplification of the DNA originating from S. equi was observed within 60 min incubation, but no amplification of non-S. equi DNA occurred. The results were identical to those of seM semi-nested PCR. To investigate the clinical usefulness of the methods, the seM-LAMP and the seM semi-nested PCR were used to screen 590 nasal swabs obtained during an outbreak of strangles. Both methods showed that 79 and 511 swabs were S. equi positive and negative, respectively, and the results were identical to those of the culture examination. These results indicate that the seM-LAMP is potentially useful for the reliable routine diagnosis of Streptococcus equi subsp. equi infections.

SEM-EDX analysis of an unknown "known" white powder found in a shipping container from Peru

NASA Astrophysics Data System (ADS)

Albright, Douglas C.

2009-05-01

In 2008, an unknown white powder was discovered spilled inside of a shipping container of whole kernel corn during an inspection by federal inspectors in the port of Baltimore, Maryland. The container was detained and quarantined while a sample of the powder was collected and sent to a federal laboratory where it was screened using chromatography for the presence of specific poisons and pesticides with negative results. Samples of the corn kernels and the white powder were forwarded to the Food and Drug Administration, Forensic Chemistry Center for further analysis. Stereoscopic Light Microscopy (SLM), Scanning Electron Microscopy/Energy Dispersive X-ray Spectrometry (SEM/EDX), and Polarized Light Microscopy/Infrared Spectroscopy (PLM-IR) were used in the analysis of the kernels and the unknown powder. Based on the unique particle analysis by SLM and SEM as well as the detection of the presence of aluminum and phosphorous by EDX, the unknown was determined to be consistent with reacted aluminum phosphide (AlP). While commonly known in the agricultural industry, aluminum phosphide is relatively unknown in the forensic community. A history of the use and acute toxicity of this compound along with some very unique SEM/EDX analysis characteristics of aluminum phosphide will be discussed.

Fundamentals of capillary electrochromatography: migration behavior of ionized sample components.

PubMed

Xiang, Rong; Horváth, Csaba

2002-02-15

The mechanism of separating charged species by capillary electrochromatography (CEC) was modeled with the conditions of ideal/linear chromatography by using a simple random walk. The most novel aspect of the work rests with the assumption that in sufficiently high electric field ionized sample components can also migrate in the adsorbed state on the ionized surface of the stationary phase. This feature of CEC leads to the introduction of three dimensionless parameters: alpha, reduced mobility of a sample component with the electrosmotic mobility as the reference; beta, the CEC retention factor; and gamma, the ratio of the electrophoretic migration velocity and the velocity of surface electrodiffusion. Since the interplay of retentive and electrophoretic forces determines the overall migration velocity, the separation mechanism in CEC is governed by the relative importance of the above parameters. The model predicts conditions under which the features of the CEC system engender migration behavior that manifests itself in a relatively narrow elution window and in a gradient like elution pattern in the separation of peptides and proteins by using pro forma isocratic CEC. It is believed that such elution patterns, which resemble those obtained by the use of external gradient of the eluent, are brought about by the formation of an internal gradient in the CEC system that gave rise to concomitant peak compression. The peculiarities of CEC are discussed in the three operational modalities of the technique: co-current, countercurrent, and co-counter CEC. The results suggest that CEC, which is often called "liquid chromatography on electrophoretic platform" is an analytical tool with great potential in the separation of peptides and proteins.

Discussing End-of-Life Decisions in a Clinical Ethics Committee: An Interview Study of Norwegian Doctors' Experience.

PubMed

Bahus, Marianne K; Førde, Reidun

2016-09-01

With disagreement, doubts, or ambiguous grounds in end-of-life decisions, doctors are advised to involve a clinical ethics committee (CEC). However, little has been published on doctors' experiences with discussing an end-of-life decision in a CEC. As part of the quality assurance of this work, we wanted to find out if clinicians have benefited from discussing end-of-life decisions in CECs and why. We will disseminate some Norwegian doctors' experiences when discussing end-of-life decisions in CECs, based on semi-structured interviews with fifteen Norwegian physicians who had brought an end-of-life decision case to a CEC. Almost half of the cases involved conflicts with the patients' relatives. In a majority of the cases, there was uncertainty about what would be the ethically preferable solution. Reasons for referring the case to the CEC were to get broader illumination of the case, to get perspective from people outside the team, to get advice, or to get moral backing on a decision already made. A great majority of the clinicians reported an overall positive experience with the CECs' discussions. In cases where there was conflict, the clinicians reported less satisfaction with the CECs' discussions. The study shows that most doctors who have used a CEC in an end-of-life decision find it useful to have ethical and/or legal aspects illuminated, and to have the dilemma scrutinized from a new perspective. A systematic discussion seems to be significant to the clinicians.

Contaminants of emerging concern in reverse osmosis brine concentrate from indirect/direct water reuse applications.

PubMed

Romeyn, Travis R; Harijanto, Wesley; Sandoval, Sofia; Delagah, Saied; Sharbatmaleki, Mohamadali

2016-01-01

Water shortage is becoming more common due to droughts and global population increases resulting in the increasing popularity of water reuse to create new water sources. Reverse osmosis (RO) membrane systems are popular in these applications since they can produce drinking water quality effluent. Unfortunately, RO systems have the drawback of generating concentrate streams that contain contaminants rejected by the membrane including chemicals of emerging concern (CECs). CECs are chemicals such as hormones, steroids, pesticides, pharmaceuticals, and personal care products that are used for their intended purpose and then released into wastewater. CECs are believed to be detrimental to aquatic wildlife health and pose an unknown human health risk. This research gathered the existing knowledge on CEC presence in concentrate, available proven concentrate treatment methods, their CEC removal abilities, and current CEC regulations. It was found that 127 CECs have been measured in RO concentrate with 100 being detected at least once. The most potent treatment process available is UV/H2O2 as it offers the highest removal rates for the widest range of chemicals. The less expensive process of ozone/biologically activated carbon offers slightly lower removal abilities. This comprehensive report will provide the groundwork for better understanding, regulating and treating concentrate stream CECs.

Applications of Biomaterials in Corneal Endothelial Tissue Engineering.

PubMed

Wang, Tsung-Jen; Wang, I-Jong; Hu, Fung-Rong; Young, Tai-Horng

2016-11-01

When corneal endothelial cells (CECs) are diseased or injured, corneal endothelium can be surgically removed and tissue from a deceased donor can replace the original endothelium. Recent major innovations in corneal endothelial transplantation include replacement of diseased corneal endothelium with a thin lamellar posterior donor comprising a tissue-engineered endothelium carried or cultured on a thin substratum with an organized monolayer of cells. Repairing CECs is challenging because they have restricted proliferative ability in vivo. CECs can be cultivated in vitro and seeded successfully onto natural tissue materials or synthetic polymeric materials as grafts for transplantation. The optimal biomaterials for substrata of CEC growth are being investigated. Establishing a CEC culture system by tissue engineering might require multiple biomaterials to create a new scaffold that overcomes the disadvantages of single biomaterials. Chitosan and polycaprolactone are biodegradable biomaterials approved by the Food and Drug Administration that have superior biological, degradable, and mechanical properties for culturing substratum. We successfully hybridized chitosan and polycaprolactone into blended membranes, and demonstrated that CECs proliferated, developed normal morphology, and maintained their physiological phenotypes. The interaction between cells and biomaterials is important in tissue engineering of CECs. We are still optimizing culture methods for the maintenance and differentiation of CECs on biomaterials.

SEM-microphotogrammetry, a new take on an old method for generating high-resolution 3D models from SEM images.

PubMed

Ball, A D; Job, P A; Walker, A E L

2017-08-01

The method we present here uses a scanning electron microscope programmed via macros to automatically capture dozens of images at suitable angles to generate accurate, detailed three-dimensional (3D) surface models with micron-scale resolution. We demonstrate that it is possible to use these Scanning Electron Microscope (SEM) images in conjunction with commercially available software originally developed for photogrammetry reconstructions from Digital Single Lens Reflex (DSLR) cameras and to reconstruct 3D models of the specimen. These 3D models can then be exported as polygon meshes and eventually 3D printed. This technique offers the potential to obtain data suitable to reconstruct very tiny features (e.g. diatoms, butterfly scales and mineral fabrics) at nanometre resolution. Ultimately, we foresee this as being a useful tool for better understanding spatial relationships at very high resolution. However, our motivation is also to use it to produce 3D models to be used in public outreach events and exhibitions, especially for the blind or partially sighted. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

A ‘NanoSuit’ surface shield successfully protects organisms in high vacuum: observations on living organisms in an FE-SEM

PubMed Central

Takaku, Yasuharu; Suzuki, Hiroshi; Ohta, Isao; Tsutsui, Takami; Matsumoto, Haruko; Shimomura, Masatsugu; Hariyama, Takahiko

2015-01-01

Although extremely useful for a wide range of investigations, the field emission scanning electron microscope (FE-SEM) has not allowed researchers to observe living organisms. However, we have recently reported that a simple surface modification consisting of a thin extra layer, termed ‘NanoSuit’, can keep organisms alive in the high vacuum (10−5 to 10−7 Pa) of the SEM. This paper further explores the protective properties of the NanoSuit surface-shield. We found that a NanoSuit formed with the optimum concentration of Tween 20 faithfully preserves the integrity of an organism's surface without interfering with SEM imaging. We also found that electrostatic charging was absent as long as the organisms were alive, even if they had not been coated with electrically conducting materials. This result suggests that living organisms possess their own electrical conductors and/or rely on certain properties of the surface to inhibit charging. The NanoSuit seems to prolong the charge-free condition and increase survival time under vacuum. These findings should encourage the development of more sophisticated observation methods for studying living organisms in an FE-SEM. PMID:25631998

The intersection of climate/environment, food, nutrition and health: crisis and opportunity.

PubMed

Raiten, Daniel J; Aimone, Ashley M

2017-04-01

Climate/environmental change (C-E-C) is affecting human health and quality of life. Significant attention has been given to the impact of C-E-C on food supply, and food as a vehicle for exposure. However, C-E-C has been superimposed on prevalent malnutrition, infectious and non-communicable diseases. We discuss why nutrition is not synonymous with food and must be viewed as a biological variable that affects and is affected by both C-E-C as well as the current global health challenges. The nexus of C-E-C, food, nutrition and health must be considered in the development of safe and efficacious interventions. A case is presented for how the convergence of C-E-C, food/nutrition and health, presents an opportunity for more integrated approaches to achieve global health goals. Published by Elsevier Ltd.

Effects of Missing Data Methods in SEM under Conditions of Incomplete and Nonnormal Data

ERIC Educational Resources Information Center

Li, Jian; Lomax, Richard G.

2017-01-01

Using Monte Carlo simulations, this research examined the performance of four missing data methods in SEM under different multivariate distributional conditions. The effects of four independent variables (sample size, missing proportion, distribution shape, and factor loading magnitude) were investigated on six outcome variables: convergence rate,…

Overlay of multiframe SEM images including nonlinear field distortions

NASA Astrophysics Data System (ADS)

Babin, S.; Borisov, S.; Ivonin, I.; Nakazawa, S.; Yamazaki, Y.

2018-03-01

To reduce charging and shrinkage, CD-SEMs utilize low electron energies and multiframe imaging. This results in every next frame being altered due to stage and beam instability, as well as due to charging. Regular averaging of the frames blurs the edges; this directly effects the extracted values of critical dimensions. A technique was developed to overlay multiframe images without the loss of quality. This method takes into account drift, rotation, and magnification corrections, as well as nonlinear distortions due to wafer charging. A significant improvement in the signal to noise ratio and overall image quality without degradation of the feature's edge quality was achieved. The developed software is capable of working with regular and large size images up to 32K pixels in each direction.

Contact inspection of Si nanowire with SEM voltage contrast

NASA Astrophysics Data System (ADS)

Ohashi, Takeyoshi; Yamaguchi, Atsuko; Hasumi, Kazuhisa; Ikota, Masami; Lorusso, Gian; Horiguchi, Naoto

2018-03-01

A methodology to evaluate the electrical contact between nanowire (NW) and source/drain (SD) in NW FETs was investigated with SEM voltage contrast (VC). The electrical defects were robustly detected by VC. The validity of the inspection result was verified by TEM physical observations. Moreover, estimation of the parasitic resistance and capacitance was achieved from the quantitative analysis of VC images which were acquired with different scan conditions of electron beam (EB). A model considering the dynamics of EB-induce charging was proposed to calculate the VC. The resistance and capacitance can be determined by comparing the model-based VC with experimentally obtained VC. Quantitative estimation of resistance and capacitance would be valuable not only for more accurate inspection, but also for identification of the defect point.

Assessment of heavy metals pollution using AVS-SEM and fractionation techniques in Edku Lagoon sediments, Mediterranean Sea, Egypt.

PubMed

El Zokm, Gehan M; Okbah, Mohamed A; Younis, Alaa M

2015-01-01

A method is presented to evaluate the fractionation of metals (Fe, Zn, Cu, Pb, Cd and Ni), acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) in Edku lagoon sediments. Thirteen sediment samples were collected from the study area in the period of 2010-2011 to assess the potential bioavailability and toxicity of the selected metals. According to classification of the Interim Sediment Quality Quidelines (ISQG), five stations near the drains exhibited 10% toxic probability. The high AVS and low ∑SEM ranges in Summer were identified as 6-138 and 0.86-3.3 µmol g(-1) dry wet, respectively which are referring to the low mobility of heavy metals in this season and vice versa for winter (2.5-23.9 and 1.16-3.82 µmol g(-1) dry wet, respectively). According to the evaluation of USEPA, all sediment samples showed ∑SEM/AVS < 1 and ΣSEM-AVS < 0 and this indicates that Edku lagoon sediments didn't cause any adverse effects. Meanwhile, the calculations of the global contamination factor (GCF) and the individual contamination factors (ICF) using fractionation technique gave values of 111.644 and 84.555 in El Bosily drain and station 1 near the cages of fish farm, respectively due to possible contamination. Interestingly, the collected data refer that the mobility and bioavailability of heavy metals in Edku lagoon sediments posed a low risk of adverse biological effects due to cadmium, copper, lead, nickel and zinc in all evaluated stations.

Protective effects of a zinc-hydroxyapatite toothpaste on enamel erosion: SEM study

PubMed Central

Colombo, Marco; Beltrami, Riccardo; Rattalino, Davide; Mirando, Maria; Chiesa, Marco; Poggio, Claudio

2016-01-01

Summary Aim The aim of the present in vitro study was to evaluate the protective effects of a zinc-hydroxyapatite toothpaste against an erosive challenge produced by a soft drink (Coca-Cola) using Scanning Electron Microscopy (SEM). Methods Forty specimens were assigned to 4 groups of 10 specimens each (group 1: no erosive challenge, no toothpaste treatment, group 2: erosive challenge, no toothpaste treatment, group 3: erosive challenge, fluoride toothpaste treatment, group 4: erosive challenge, zinc-hydroxyapatite toothpaste treatment). The surface of each specimen was imaged by SEM. A visual rating system was used to evaluate the condition of the enamel surface; results were analyzed by nonparametric statistical methods. Results Statistically significant differences were found between the samples untreated and those immersed in Coca-Cola (group 1, 2); the highest grade of damage was found in group 2, while the lowest grade was recorded in the samples of group 4. Comparing the groups, the two analyzed toothpaste tended to protect in different extend. Conclusions In this study treatment of erosively challenged enamel with Zn-Hap toothpaste showed a clear protective effect. This was greater than the effect observed for a normal fluoride toothpaste and confirmed the potential benefit the Zn-HAP technology can provide in protecting enamel from erosive acid challenges. PMID:28149449

Protective effects of a zinc-hydroxyapatite toothpaste on enamel erosion: SEM study.

PubMed

Colombo, Marco; Beltrami, Riccardo; Rattalino, Davide; Mirando, Maria; Chiesa, Marco; Poggio, Claudio

2016-01-01

The aim of the present in vitro study was to evaluate the protective effects of a zinc-hydroxyapatite toothpaste against an erosive challenge produced by a soft drink (Coca-Cola) using Scanning Electron Microscopy (SEM). Forty specimens were assigned to 4 groups of 10 specimens each (group 1: no erosive challenge, no toothpaste treatment, group 2: erosive challenge, no toothpaste treatment, group 3: erosive challenge, fluoride toothpaste treatment, group 4: erosive challenge, zinc-hydroxyapatite toothpaste treatment). The surface of each specimen was imaged by SEM. A visual rating system was used to evaluate the condition of the enamel surface; results were analyzed by nonparametric statistical methods. Statistically significant differences were found between the samples untreated and those immersed in Coca-Cola (group 1, 2); the highest grade of damage was found in group 2, while the lowest grade was recorded in the samples of group 4. Comparing the groups, the two analyzed toothpaste tended to protect in different extend. In this study treatment of erosively challenged enamel with Zn-Hap toothpaste showed a clear protective effect. This was greater than the effect observed for a normal fluoride toothpaste and confirmed the potential benefit the Zn-HAP technology can provide in protecting enamel from erosive acid challenges.

Marginal adaptation of newer root canal sealers to dentin: A SEM study.

PubMed

Polineni, Swapnika; Bolla, Nagesh; Mandava, Pragna; Vemuri, Sayesh; Mallela, Madhusudana; Gandham, Vijaya Madhuri

2016-01-01

This in vitro study evaluated and compared the marginal adaptation of three newer root canal sealers to root dentin. Thirty freshly extracted human single-rooted teeth with completely formed apices were taken. Teeth were decoronated, and root canals were instrumented. The specimens were randomly divided into three groups (n = 10) based upon the sealer used. Group 1 - teeth were obturated with epoxy resin sealer (MM-Seal). Group 2 - teeth were obturated with mineral trioxide aggregate (MTA) based sealer (MTA Fillapex), Group 3 - teeth were obturated with bioceramic sealer (EndoSequence BC sealer). Later samples were vertically sectioned using hard tissue microtome and marginal adaptation of sealers to root dentin was evaluated under coronal and apical halves using scanning electron microscopy (SEM) and marginal gap values were recorded. The data were statistically analyzed by two-way ANOVA and Tukey's multiple post hoc test. The highest marginal gap was seen in Group 2 (apical-16680.00 nm, coronal-10796 nm) and the lowest marginal gap was observed in Group 1 (apical-599.42 nm, coronal-522.72 nm). Coronal halves showed superior adaptation compared to apical halves in all the groups under SEM. Within the limitations of this study epoxy resin-based MM-Seal showed good marginal adaptation than other materials tested.

A novel approach to TEM preparation with a (7-axis stage) triple-beam FIB-SEM system

NASA Astrophysics Data System (ADS)

Clarke, Jamil J.

2015-10-01

Preparation of lamellae from bulk to grid for Cs-corrected Transmission Electron Microscope (TEM) observation has mostly become routine work on the latest FIB-SEM systems, with standardized techniques that often are left to automation for the initial steps. The finalization of lamellae however, has mostly become, non-routine, non-repeatable and often driven by user experience level in most cases to produce high quality damage-less cross section. Materials processing of the latest technologies, with ever-shrinking Nano-sized structures pose challenges to modern FIB-SEM systems. This can often lead to specialized techniques and hyper-specific functions for producing ultra-thin high quality lamellae that often are lab specific, preventing practical use of such techniques across multiple materials and applications. Several factors that should be incorporated in processing fine structured materials successfully include how the use of electron and ion scan conditions can affect a thin section during ion milling, the type of ion species applied for material processing during the finalization of lamellae with gallium ions or of a smaller ion species type such as Ar/Xe, sample orientation of the lamella during the thinning process which is linked to ion beam incident angle as a direct relationship in the creation of waterfall effects or curtain effects, and how software can be employed to aid in the reduction of these artifacts with reproducible results regardless of FIB-SEM experience for site-specific lift outs. A traditional TEM preparation was performed of a fine structure specimen in pursuit of a process technique to produce a high quality TEM lamella which would address all of the factors mentioned. These new capabilities have been refined and improved upon during the FIB-SEM design and development stages with an end result of a new approach that yields an improvement in quality by the reduction of common ion milling artifacts such as curtain effects, amorphous

The Great War and Remembrance in Jose Leon Machado's "Memoria das Estrelas sem Brilho"

ERIC Educational Resources Information Center

Azevedo, Milton M.

2011-01-01

This article analyzes Jose Leon Machado's novel, "Memoria das Estrelas sem Brilho," as a multilayered historical novel in which a war story provides a background for comments on aspects of early twentieth-century Portuguese society, such as male bonding, religion, sexual mores, and social stratification. (Contains 11 notes.)

Exploring the interior of cuticles and compressions of fossil plants by FIB-SEM milling and image microscopy.

PubMed

Sender, L M; Escapa, I; Benedetti, A; Cúneo, R; Diez, J B

2018-01-01

We present the first study of cuticles and compressions of fossil leaves by Focused Ion Beam Scanning Electron Microscopy (FIB-SEM). Cavities preserved inside fossil leaf compressions corresponding to substomatal chambers have been observed for the first time and several new features were identified in the cross-section cuts. These results open a new way in the investigation of the three-dimensional structures of both micro- and nanostructural features of fossil plants. Moreover, the application of the FIB-SEM technique to both fossils and extant plant remains represent a new source of taxonomical, palaeoenvironmental and palaeoclimatic information. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Comparison of Circulating Endothelial Cell/Platelet Count Ratio to Aspartate Transaminase/Platelet Ratio Index for Identifying Patients with Cirrhosis

PubMed Central

Sethi, Saurabh; Simonetto, Douglas A; Abdelmoneim, Soha S; Campion, Michael B; Kaloiani, Irakli; Clayton, Amy C; Kremers, Walter K; Halling, Kevin C; Kamath, Patrick S; Talwalkar, Jayant; Shah, Vijay H

2012-01-01

Background/Objectives Circulating endothelial cells (CECs) are indicative of vascular injury and correlate with severity of vascular diseases. A pilot study showed that the ratio of CEC to platelet count (CEC/PC) was effective in predicting cirrhosis. Therefore, we evaluated CEC/PC in a larger cohort of patients, correlated it with cirrhosis, and compared its operating characteristics with previously described biomarker for cirrhosis, the AST/platelet ratio index (APRI). Methods Fifty-three patients with cirrhosis, 20 matched healthy controls, and 9 patients with noncirrhotic liver disease were recruited. Peripheral blood sample was collected and analyzed to enumerate nucleated CEC CD146+, CD105+, CD45– using a commercial assay. Results Median CEC counts were significantly higher in patients with cirrhosis (62 cells/4 mL, interquartile range [IQR]: 43.5–121) as compared with controls (31 cells/4 mL, IQR: 22.2–40). The CEC/PC was also significantly elevated in cirrhotics (0.69, IQR: 0.39–1.48) compared with controls (0.12, IQR: 0.09–0.20) and noncirrhotics (0.21, IQR: 0.08–0.43). Receiver operator characteristic (ROC) analysis revealed that CEC cutoff value of ≥37 cells/4 mL showed sensitivity of 81% and specificity of 75% for differentiating cirrhosis from controls (area under the curve [AUC]: 0.80; 95% confidence interval [CI] 0.67–0.91). The CEC/PC ratio cutoff value of ≥0.23 showed sensitivity of 91% and specificity of 82% (AUC: 0.92; 95% CI 0.83–0.99). The APRI cutoff value of ≥0.4 showed sensitivity of 94% and specificity of 85% for differentiating cirrhosis from control patients (AUC: 0.96; 95% CI 0.90–1.0). A product of CEC and APRI, termed CAPRI (CEC-APRI), effectively distinguished patients with cirrhosis from controls; with cutoff value of ≥12.7, showing higher sensitivity of 98% and specificity of 85% (AUC: 0.98; 95% CI 0.96–1.0). Conclusion The CEC/PC ratio is significantly elevated in patients with cirrhosis and demonstrates

The C. elegans SoxC protein SEM-2 opposes differentiation factors to promote a proliferative blast cell fate in the postembryonic mesoderm

PubMed Central

Tian, Chenxi; Shi, Herong; Colledge, Clark; Stern, Michael; Waterston, Robert; Liu, Jun

2011-01-01

The proper development of multicellular organisms requires precise regulation and coordination of cell fate specification, cell proliferation and differentiation. Abnormal regulation and coordination of these processes could lead to disease, including cancer. We have examined the function of the sole C. elegans SoxC protein, SEM-2, in the M lineage, which produces the postembryonic mesoderm. We found that SEM-2/SoxC is both necessary and sufficient to promote a proliferating blast cell fate, the sex myoblast fate, over a differentiated striated bodywall muscle fate. A number of factors control the specific expression of sem-2 in the sex myoblast precursors and their descendants. This includes direct control of sem-2 expression by a Hox-PBC complex. The crucial nature of the HOX/PBC factors in directly enhancing expression of this proliferative factor in the C. elegans M lineage suggests a possible more general link between Hox-PBC factors and SoxC proteins in regulating cell proliferation. PMID:21307099

SEMTAP (Serpentine End Match TApe program): The Easy Way to Program Your Numerically Controlled Router for the Production of SEM Joints

Treesearch

Ronald E. Coleman

1977-01-01

SEMTAP (Serpentine End Match TApe Program) is an easy and inexpensive method of programing a numerically controlled router for the manufacture of SEM (Serpentine End Matching) joints. The SEMTAP computer program allows the user to issue commands that will accurately direct a numerically controlled router along any SEM path. The user need not be a computer programer to...

Sediment nickel bioavailability and toxicity to estuarine crustaceans of contrasting bioturbative behaviors--an evaluation of the SEM-AVS paradigm.

PubMed

Chandler, G Thomas; Schlekat, Christian E; Garman, Emily R; He, Lijian; Washburn, Katherine M; Stewart, Emily R; Ferry, John L

2014-11-04

Robust sediment quality criteria require chemistry and toxicity data predictive of concentrations where population/community response should occur under known geochemical conditions. Understanding kinetic and geochemical effects on toxicant bioavailability is key, and these are influenced by infaunal sediment bioturbation. This study used fine-scale sediment and porewater measurement of contrasting infaunal effects on carbon-normalized SEM-AVS to evaluate safe or potentially toxic nickel concentrations in a high-binding Spartina saltmarsh sediment (4%TOC; 35-45 μmol-S2-·g(-1)). Two crustaceans producing sharply contrasting bioturbation--the copepod Amphiascus tenuiremis and amphipod Leptocheirus plumulosus--were cultured in oxic to anoxic sediments with SEM[Ni]-AVS, TOC, porewater [Ni], and porewater DOC measured weekly. From 180 to 750 μg-Ni·g(-1) sediment, amphipod bioturbation reduced [AVS] and enhanced porewater [Ni]. Significant amphipod uptake, mortality, and growth-depression occurred at the higher sediment [Ni] even when [SEM-AVS]/foc suggested acceptable risk. Less bioturbative copepods produced higher AVS and porewater DOC but exhibited net population growth despite porewater [Ni] 1.3-1.7× their aqueous [Ni] LOEC. Copepod aqueous tests with/without dissolved organic matter showed significant aqueous DOC protection, which suggests porewater DOC attenuates sediment Ni toxicity. The SEM[Ni]-AVS relationship was predictive of acceptable risk for copepods at the important population-growth level.

GUIDELINES FOR THE APPLICATION OF SEM/EDX ANALYTICAL TECHNIQUES FOR FINE AND COARSE PM SAMPLES

EPA Science Inventory

Scanning Electron Microscopy (SEM) coupled with Energy-Dispersive X-ray analysis (EDX) is a powerful tool in the characterization and source apportionment of environmental particulate matter (PM), providing size, chemistry, and morphology of particles as small as a few tenths ...

Labyrinths, columns and cavities: new internal features of pollen grain walls in the Acanthaceae detected by FIB-SEM.

PubMed

House, Alisoun; Balkwill, Kevin

2016-03-01

External pollen grain morphology has been widely used in the taxonomy and systematics of flowering plants, especially the Acanthaceae which are noted for pollen diversity. However internal pollen wall features have received far less attention due to the difficulty of examining the wall structure. Advancing technology in the field of microscopy has made it possible, with the use of a focused ion beam-scanning electron microscope (FIB-SEM), to view the structure of pollen grain walls in far greater detail and in three dimensions. In this study the wall structures of 13 species from the Acanthaceae were investigated for features of potential systematic relevance. FIB-SEM was applied to obtain precise cross sections of pollen grains at selected positions for examining the wall ultrastructure. Exploratory studies of the exine have thus far identified five basic structural types. The investigations also show that similar external pollen wall features may have a distinctly different internal structure. FIB-SEM studies have revealed diverse internal pollen wall features which may now be investigated for their systematic and functional significance.

Altering calcium influx for selective destruction of breast tumor.

PubMed

Yu, Han-Gang; McLaughlin, Sarah; Newman, Mackenzie; Brundage, Kathleen; Ammer, Amanda; Martin, Karen; Coad, James

2017-03-04

Human triple-negative breast cancer has limited therapeutic choices. Breast tumor cells have depolarized plasma membrane potential. Using this unique electrical property, we aim to develop an effective selective killing of triple-negative breast cancer. We used an engineered L-type voltage-gated calcium channel (Cec), activated by membrane depolarization without inactivation, to induce excessive calcium influx in breast tumor cells. Patch clamp and flow cytometry were used in testing the killing selectivity and efficiency of human breast tumor cells in vitro. Bioluminescence and ultrasound imaging were used in studies of human triple-negative breast cancer cell MDA-MB-231 xenograft in mice. Histological staining, immunoblotting and immunohistochemistry were used to investigate mechanism that mediates Cec-induced cell death. Activating Cec channels expressed in human breast cancer MCF7 cells produced enormous calcium influx at depolarized membrane. Activating the wild-type Cav1.2 channels expressed in MCF7 cells also produced a large calcium influx at depolarized membrane, but this calcium influx was diminished at the sustained membrane depolarization due to channel inactivation. MCF7 cells expressing Cec died when the membrane potential was held at -10 mV for 1 hr, while non-Cec-expressing MCF7 cells were alive. MCF7 cell death was 8-fold higher in Cec-expressing cells than in non-Cec-expressing cells. Direct injection of lentivirus containing Cec into MDA-MB-231 xenograft in mice inhibited tumor growth. Activated caspase-3 protein was detected only in MDA-MB-231 cells expressing Cec, along with a significantly increased expression of activated caspase-3 in xenograft tumor treated with Cec. We demonstrated a novel strategy to induce constant calcium influx that selectively kills human triple-negative breast tumor cells.

Bioactive contaminants of emerging concern in National Park waters of the northern Colorado Plateau, USA

USGS Publications Warehouse

Weissinger, Rebecca H; Blackwell, Brett R.; Keteles, Kristen; Battaglin, William A.; Bradley, Paul M.

2018-01-01

Pharmaceuticals and personal care products (PPCPs), wastewater indicators (WWIs), and pesticides (herein, Contaminants of Emerging Concern [CECs]) have been documented in surface waters throughout the world and have associated risks to aquatic life. While much research has focused on temperate and urbanized watersheds, less is known about CEC presence in semi-arid landscapes, where water availability is limited and populations are low. CEC presence in water and sediment is reported for 21 sites in eight U.S. national parks in the northern Colorado Plateau region. From 2012 to 2016, at least one PPCP and/or WWI was detected at most sites on over half of sampling visits, indicating that CECs are not uncommon even in isolated areas. CEC detections were generally fewer and at lower concentrations than in urbanized or agricultural watersheds. Consistent with studies from other U.S. regions, the most frequently detected CECs in this study include DEET, caffeine, organophosphorus flame retardants, and bisphenol A in water and fecal indicators and polycyclic aromatic hydrocarbons in sediment. Maximum concentrations in this study were generally below available water quality benchmarks, sediment quality guidelines, and risk assessment thresholds associated with vertebrates. Additional work is needed to assess the potential activity of hormones, which had high reporting limits in our study, and potential bioactivity of environmental concentrations for invertebrates, microbial communities, and algae. Potential sources of CEC contamination include upstream wastewater effluent discharges and National Park Service invasive-plant-control herbicide applications. CEC occurrence patterns and similarities between continuous and isolated flow locations suggest that direct contamination from individual visitors may also occur. While our data indicate there is little aquatic health risk associated with CECs at our sites, our results demonstrate the ubiquity of CECs on the landscape and a

The Application of SEM to Behavioral Research in Oncology: Past Accomplishments and Future Opportunities

ERIC Educational Resources Information Center

Schnoll, Robert A.; Fang, Carolyn Y.; Manne, Sharon L.

2004-01-01

The past decade has seen a tremendous growth in the use of structural equation modeling (SEM) to address research questions in 2 subfields of behavioral science: cancer prevention and control (e.g., determinants of cancer screening adherence) and behavioral oncology (e.g., determinants of psychosocial adjustment among cancer patients or…

Morphology of the European species of the aphid genus Eulachnus (Hemiptera: Aphididae: Lachninae) - A SEM comparative and integrative study.

PubMed

Kanturski, Mariusz; Karcz, Jagna; Wieczorek, Karina

2015-09-01

Scanning electron microscopy (SEM) methods were used for the first time to elucidate the external morphology of the European species of the genus Eulachnus (Hemiptera: Aphididae: Lachninae), a representative genus of the conifer-feeding aphids tribe Eulachnini. We examined and compared the external morphology of apterous and alate viviparous females from the parthenogenetic generation as well as oviparous females and alate males belonging to the sexual generation. FE-SEM images based on HMDS and cryo-SEM preparation techniques revealed better image quality than the CPD technique in regard to surface tension and morphological signs of cell deteriorations (i.e., existence of depressions, drying artifacts and membrane blebs). Three morphologically different species groups "agilis", "brevipilosus" and "cembrae" were proposed due to the differences in head, antennae, legs and dorsal chaetotaxy as well as dorsal sclerotization. The most characteristic features and differences of representatives of these groups are presented and discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Three-dimensional analysis of somatic mitochondrial dynamics in fission-deficient injured motor neurons using FIB/SEM.

PubMed

Tamada, Hiromi; Kiryu-Seo, Sumiko; Hosokawa, Hiroki; Ohta, Keisuke; Ishihara, Naotada; Nomura, Masatoshi; Mihara, Katsuyoshi; Nakamura, Kei-Ichiro; Kiyama, Hiroshi

2017-08-01

Mitochondria undergo morphological changes through fusion and fission for their quality control, which are vital for neuronal function. In this study, we examined three-dimensional morphologies of mitochondria in motor neurons under normal, nerve injured, and nerve injured plus fission-impaired conditions using the focused ion beam/scanning electron microscopy (FIB/SEM), because the FIB/SEM technology is a powerful tool to demonstrate both 3D images of whole organelle and the intra-organellar structure simultaneously. Crossing of dynamin-related protein 1 (Drp1) gene-floxed mice with neuronal injury-specific Cre driver mice, Atf3:BAC Tg mice, allowed for Drp1 ablation specifically in injured neurons. FIB/SEM analysis demonstrated that somatic mitochondrial morphologies in motor neurons were not altered before or after nerve injury. However, the fission impairment resulted in prominent somatic mitochondrial enlargement, which initially induced complex morphologies with round regions and long tubular processes, subsequently causing a decrease in the number of processes and further enlargement of the round regions, which eventually resulted in big spheroidal mitochondria without processes. The abnormal mitochondria exhibited several degradative morphologies: local or total cristae collapse, vacuolization, and mitophagy. These suggest that mitochondrial fission is crucial for maintaining mitochondrial integrity in injured motor neurons, and multiple forms of mitochondria degradation may accelerate neuronal degradation. © 2017 Wiley Periodicals, Inc.

AFM and SEM study of the effects of etching on IPS-Empress 2 TM dental ceramic

NASA Astrophysics Data System (ADS)

Luo, X.-P.; Silikas, N.; Allaf, M.; Wilson, N. H. F.; Watts, D. C.

2001-10-01

The aim of this study was to investigate the effects of increasing etching time on the surface of the new dental material, IPS-Empress 2 TM glass ceramic. Twenty one IPS-Empress 2 TM glass ceramic samples were made from IPS-Empress 2 TM ingots through lost-wax, hot-pressed ceramic fabrication technology. All samples were highly polished and cleaned ultrasonically for 5 min in acetone before and after etching with 9.6% hydrofluoric acid gel. The etching times were 0, 10, 20, 30, 60, 90 and 120 s respectively. Microstructure was analysed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) was used to evaluate the surface roughness and topography. Observations with SEM showed that etching with hydrofluoric acid resulted in preferential dissolution of glass matrix, and that partially supported crystals within the glass matrix were lost with increasing etching time. AFM measurements indicated that etching increased the surface roughness of the glass-ceramic. A simple least-squares linear regression was used to establish a relationship between surface roughness parameters ( Ra, RMS), and etching time, for which r2>0.94. This study demonstrates the benefits of combining two microscopic methods for a better understanding of the surface. SEM showed the mode of action of hydrofluoric acid on the ceramic and AFM provided valuable data regarding the extent of surface degradation relative to etching time.

Clinical value of circulating endothelial cell levels in metastatic colorectal cancer patients treated with first-line chemotherapy and bevacizumab.

PubMed

Malka, D; Boige, V; Jacques, N; Vimond, N; Adenis, A; Boucher, E; Pierga, J Y; Conroy, T; Chauffert, B; François, E; Guichard, P; Galais, M P; Cvitkovic, F; Ducreux, M; Farace, F

2012-04-01

We investigated whether circulating endothelial cells (CECs) predict clinical outcome of first-line chemotherapy and bevacizumab in metastatic colorectal cancer (mCRC) patients. In a substudy of the randomized phase II FNCLCC ACCORD 13/0503 trial, CECs (CD45- CD31+ CD146+ 7-amino-actinomycin- cells) were enumerated in 99 patients by four-color flow cytometry at baseline and after one cycle of treatment. We correlated CEC levels with objective response rate (ORR), 6-month progression-free survival (PFS) rate (primary end point of the trial), PFS, and overall survival (OS). Multivariate analyses of potential prognostic factors, including CEC counts and Köhne score, were carried out. By multivariate analysis, high baseline CEC levels were the only independent prognostic factor for 6-month PFS rate (P < 0.01) and were independently associated with worse PFS (P = 0.02). High CEC levels after one cycle were the only independent prognostic factor for ORR (P = 0.03). High CEC levels at both time points independently predicted worse ORR (P = 0.025), 6-month PFS rate (P = 0.007), and PFS (P = 0.02). Köhne score was the only variable associated with OS. CEC levels at baseline and after one treatment cycle may independently predict ORR and PFS in mCRC patients starting first-line bevacizumab and chemotherapy.

SEM stereo-section fractography observations. Final report

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

Zhang, X.J.; Tregoning, R.L.; Armstrong, R.W.

1998-05-01

Cleavage initiation in engineering materials is governed by local microstructural inhomogeneities. These features are often the principal reason for the large scatter evident in fracture toughness measurements which, in extreme cases, can mask the fundamental relationship between cracking resistance and global material properties. The SEM stereo-section fractography (SSF) technique can be used to carefully evaluate these local inhomogeneities through simultaneous observation of both the fracture surface and the underlying microstructure. By sectioning the fracture surface close to the cleavage initiation site (within 10 microns), and perpendicular to both the fracture surface and the pre crack front, a direct correspondence betweenmore » initiation and the local microstructure can be established. Information obtained from this technique can provide quantitative input about important, local microstructural features which can then be used to calibrate or create realistic micromechanical models. A compendium of SSF results is presented herein for cleavage cracking in disparate materials (A533B steel plates, MIL-70S multi-pass weldments, and Ti6A14V forgings), under various testing conditions. In each case, the SSF technique was able to unambiguously identify the dominant, local features which triggered cleavage initiation.« less

Why Isn't Talent Development on the IEP? SEM and the Twice Exceptional Learner

ERIC Educational Resources Information Center

Baum, Susan; Novak, Cynthia

2010-01-01

Why isn't talent development included on the Individual Educational Plan of 2E students? Twice exceptional students have unique issues that respond especially well to a talent development approach especially within the context of the Schoolwide Enrichment Model. Through case studies and a review of successful projects using SEM with at risk…

Comparing Indirect Effects in SEM: A Sequential Model Fitting Method Using Covariance-Equivalent Specifications

ERIC Educational Resources Information Center

Chan, Wai

2007-01-01

In social science research, an indirect effect occurs when the influence of an antecedent variable on the effect variable is mediated by an intervening variable. To compare indirect effects within a sample or across different samples, structural equation modeling (SEM) can be used if the computer program supports model fitting with nonlinear…

cDNA cloning and characterization of the antibacterial peptide cecropin 1 from the diamondback moth, Plutella xylostella L.

PubMed

Jin, Fengliang; Sun, Qiang; Xu, Xiaoxia; Li, Linmiao; Gao, Gang; Xu, Yingjie; Yu, Xiaoqiang; Ren, Shunxiang

2012-10-01

Cecropins are linear cationic antibacterial peptides that have potent activities against microorganisms. In the present study, a 480bp full-length cDNA encoding diamondback moth (Plutella xylostella) cecropin 1 (designated as Px-cec1) was obtained using RT-PCR. A Northern blot analysis showed that the Px-cec1 transcript was predominantly expressed in fat bodies, hemocytes, midgut and epidermis with the highest expression level in fat bodies. The expression of Px-cec1 mRNA in fat bodies was significantly increased 24h after microbial challenge, with the highest induced expression by Staphylococcus aureus. A circular dichroism (CD) analysis revealed that the recombinant Px-cec1 mainly contained α-helixes. Antimicrobial assays demonstrated that recombinant Px-cec1 exhibited a broad spectrum of anti-microbial properties against fungi, Gram-positive and Gram-negative bacteria, but it did not exhibit hemolytic activity against human erythrocytes. Furthermore, Px-cec1 caused significant morphological alterations of S. aureus, as shown by scanning electron microscopy and transmission electron microscopy. These results demonstrated that Px-cec1 exerts its antibacterial activity by acting on the cell membrane to disrupt bacterial cell structures. Copyright © 2012 Elsevier Inc. All rights reserved.

Decreased Soil Cation Exchange Capacity Across Northern China's Grasslands Over the Last Three Decades

NASA Astrophysics Data System (ADS)

Fang, Kai; Kou, Dan; Wang, Guanqin; Chen, Leiyi; Ding, Jinzhi; Li, Fei; Yang, Guibiao; Qin, Shuqi; Liu, Li; Zhang, Qiwen; Yang, Yuanhe

2017-11-01

Cation exchange capacity (CEC) helps soils hold nutrients and buffer pH, making it vital for maintaining basic function of terrestrial ecosystems. However, little is known about the temporal dynamics of CEC over broad geographical scales. In this study, we used random forest method to compare historical CEC data from the 1980s with new data from the 2010s across northern China's grasslands. We found that topsoil CEC in the 2010s was significantly lower than in the 1980s, with an overall decline of about 14%. Topsoil CEC decreased significantly in alpine meadow, alpine steppe, meadow steppe, and typical steppe by 11%, 20%, 27%, and 9%, respectively. Desert steppe was the only ecosystem type that experienced no significant change. CEC was positively related to soil carbon content, silt content, and mean annual precipitation, suggesting that the decline was potentially associated with soil organic carbon loss, soil degradation, soil acidification, and extreme precipitation across northern China's grasslands since the 1980s. Overall, our results demonstrate topsoil CEC loss due to environmental changes, which may alter the vegetation community composition and its productivity and thus trigger grassland dynamics under a changing environment.

Does Your SEM Really Tell the Truth?-How Would You Know? Part 4: Charging and its Mitigation.

PubMed

Postek, Michael T; Vladár, András E

2015-01-01

This is the fourth part of a series of tutorial papers discussing various causes of measurement uncertainty in scanned particle beam instruments, and some of the solutions researched and developed at NIST and other research institutions. Scanned particle beam instruments, especially the scanning electron microscope (SEM), have gone through tremendous evolution to become indispensable tools for many and diverse scientifc and industrial applications. These improvements have significantly enhanced their performance and made them far easier to operate. But, the ease of operation has also fostered operator complacency. In addition, the user-friendliness has reduced the apparent need for extensive operator training. Unfortunately, this has led to the idea that the SEM is just another expensive "digital camera" or another peripheral device connected to a computer and that all of the problems in obtaining good quality images and data have been solved. Hence, one using these instruments may be lulled into thinking that all of the potential pitfalls have been fully eliminated and believing that, everything one sees on the micrograph is always correct. But, as described in this and the earlier papers, this may not be the case. Care must always be taken when reliable quantitative data are being sought. The first paper in this series discussed some of the issues related to signal generation in the SEM, including instrument calibration, electron beam-sample interactions and the need for physics-based modeling to understand the actual image formation mechanisms to properly interpret SEM images. The second paper has discussed another major issue confronting the microscopist: specimen contamination and methods to eliminate it. The third paper discussed mechanical vibration and stage drift and some useful solutions to mitigate the problems caused by them, and here, in this the fourth contribution, the issues related to specimen "charging" and its mitigation are discussed relative to

FIB and MIP: understanding nanoscale porosity in molecularly imprinted polymers via 3D FIB/SEM tomography.

PubMed

Neusser, G; Eppler, S; Bowen, J; Allender, C J; Walther, P; Mizaikoff, B; Kranz, C

2017-10-05

We present combined focused ion beam/scanning electron beam (FIB/SEM) tomography as innovative method for differentiating and visualizing the distribution and connectivity of pores within molecularly imprinted polymers (MIPs) and non-imprinted control polymers (NIPs). FIB/SEM tomography is used in cell biology for elucidating three-dimensional structures such as organelles, but has not yet been extensively applied for visualizing the heterogeneity of nanoscopic pore networks, interconnectivity, and tortuosity in polymers. To our best knowledge, the present study is the first application of this strategy for analyzing the nanoscale porosity of MIPs. MIPs imprinted for propranolol - and the corresponding NIPs - were investigated establishing FIB/SEM tomography as a viable future strategy complementing conventional isotherm studies. For visualizing and understanding the properties of pore networks in detail, polymer particles were stained with osmium tetroxide (OsO 4 ) vapor, and embedded in epoxy resin. Staining with OsO 4 provides excellent contrast during high-resolution SEM imaging. After optimizing the threshold to discriminate between the stained polymer matrix, and pores filled with epoxy resin, a 3D model of the sampled volume may be established for deriving not only the pore volume and pore surface area, but also to visualize the interconnectivity and tortuosity of the pores within the sampled polymer volume. Detailed studies using different types of cross-linkers and the effect of hydrolysis on the resulting polymer properties have been investigated. In comparison of MIP and NIP, it could be unambiguously shown that the interconnectivity of the visualized pores in MIPs is significantly higher vs. the non-imprinted polymer, and that the pore volume and pore area is 34% and approx. 35% higher within the MIP matrix. This confirms that the templating process not only induces selective binding sites, but indeed also affects the physical properties of such

The LER/LWR metrology challenge for advance process control through 3D-AFM and CD-SEM

NASA Astrophysics Data System (ADS)

Faurie, P.; Foucher, J.; Foucher, A.-L.

2009-12-01

The continuous shrinkage in dimensions of microelectronic devices has reached such level, with typical gate length in advance R&D of less than 20nm combine with the introduction of new architecture (FinFET, Double gate...) and new materials (porous interconnect material, 193 immersion resist, metal gate material, high k materials...), that new process parameters have to be well understood and well monitored to guarantee sufficient production yield in a near future. Among these parameters, there are the critical dimensions (CD) associated to the sidewall angle (SWA) values, the line edge roughness (LER) and the line width roughness (LWR). Thus, a new metrology challenge has appeared recently and consists in measuring "accurately" the fabricated patterns on wafers in addition to measure the patterns on a repeatable way. Therefore, a great effort has to be done on existing techniques like CD-SEM, Scatterometry and 3D-AFM in order to develop them following the two previous criteria: Repeatability and Accuracy. In this paper, we will compare the 3D-AFM and CD-SEM techniques as a mean to measure LER and LWR on silicon and 193 resist and point out CD-SEM impact on the material during measurement. Indeed, depending on the material type, the interaction between the electron beam and the material or between the AFM tip and the material can vary a lot and subsequently can generate measurements bias. The first results tend to show that depending on CD-SEM conditions (magnification, number of acquisition frames) the final outputs can vary on a large range and therefore show that accuracy in such measurements are really not obvious to obtain. On the basis of results obtained on various materials that present standard sidewall roughness, we will show the limit of each technique and will propose different ways to improve them in order to fulfil advance roadmap requirements for the development of the next IC generation.

Influence of pine bark particle size and pH on cation exchange capacity

USDA-ARS?s Scientific Manuscript database

Cation exchange capacity (CEC) describes the maximum quantity of cations a soil or substrate can hold while being exchangeable with the soil solution. While CEC has been studied for peat-based substrates, relatively little work has documented factors that affect CEC of pine bark substrates. The ob...

Field emission scanning electron microscopy (FE-SEM) as an approach for nanoparticle detection inside cells.

PubMed

Havrdova, M; Polakova, K; Skopalik, J; Vujtek, M; Mokdad, A; Homolkova, M; Tucek, J; Nebesarova, J; Zboril, R

2014-12-01

When developing new nanoparticles for bio-applications, it is important to fully characterize the nanoparticle's behavior in biological systems. The most common techniques employed for mapping nanoparticles inside cells include transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). These techniques entail passing an electron beam through a thin specimen. STEM or TEM imaging is often used for the detection of nanoparticles inside cellular organelles. However, lengthy sample preparation is required (i.e., fixation, dehydration, drying, resin embedding, and cutting). In the present work, a new matrix (FTO glass) for biological samples was used and characterized by field emission scanning electron microscopy (FE-SEM) to generate images comparable to those obtained by TEM. Using FE-SEM, nanoparticle images were acquired inside endo/lysosomes without disruption of the cellular shape. Furthermore, the initial steps of nanoparticle incorporation into the cells were captured. In addition, the conductive FTO glass endowed the sample with high stability under the required accelerating voltage. Owing to these features of the sample, further analyses could be performed (material contrast and energy-dispersive X-ray spectroscopy (EDS)), which confirmed the presence of nanoparticles inside the cells. The results showed that FE-SEM can enable detailed characterization of nanoparticles in endosomes without the need for contrast staining or metal coating of the sample. Images showing the intracellular distribution of nanoparticles together with cellular morphology can give important information on the biocompatibility and demonstrate the potential of nanoparticle utilization in medicine. Copyright © 2014 Elsevier Ltd. All rights reserved.

Morphology of the adult male and pupal exuviae of Glyptotendipes (Glyptotendipes) glaucus (Meigen 1818) (Diptera, Chironomidae) using scanning electron microscope (SEM).

PubMed

Kownacki, Andrzej; Woznicka, Olga; Szarek-Gwiazda, Ewa; Michailova, Paraskeva; Czaplicka, Anna

2017-02-27

In this paper, a study of the morphology of the pupa and male imago of Glyptotendipes (G.) glaucus (Meigen 1818) was carried out, with the aid of a scanning electron microscope (SEM). The SEM provided additional valuable information on the morphology of the species. Adult male head, antenna, wing, leg, abdomen, hypopygium, pupal cephalothorax and abdomen were examined. It is emphasized that SEM was not often used in Chironomidae studies. The present results confirm SEM as a suitable approach in carrying out morphological and taxonomical descriptions of Chironomidae species.

FTIR and SEM analysis applied in tissue engineering for root recovering surgery.

PubMed

Costa, Davidson Ribeiro; Nicolau, Renata Amadei; Costa, David Ribeiro; Raniero, Leandro José; Oliveira, Marco Antonio

2017-08-01

Gingival recession is defined by the displacement of the gingival margin in the apical direction, which overcomes the cementum enamel junction. The etiology of gingival retraction is related to tissue inflammation caused by the accumulation of biofilm, by trauma from brushing action. Aesthetic periodontal surgery aims to return the root coverage to aesthetic harmony, and reduce the risk of periodontal disease and caries. To assist in the root coverage process, the porcine collagen matrix (PCM) has been widely studied. The objectives of this study are to identify the types of collagen that make up the PCM and analyze their morphology. For this, five PCM fragments, 2 mm (thickness) × 2.6 mm (width), were analyzed with the aid of scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The analysis by SEM showed that the PCM consists of two layers; the surface layer is compact, low porosity, and smooth surface, and a foamed underlying layer has high porosity. Through FTIR we identified that the surface and underlying layers are composed of collagen types I and III, respectively. This biomaterial is conducive to root coverage; it allows adsorption and cell proliferation following the matrix resorption and periodontal tissue neoformation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1326-1329, 2017. © 2015 Wiley Periodicals, Inc.

Confirmatory analysis of field-presumptive GSR test sample using SEM/EDS

NASA Astrophysics Data System (ADS)

Toal, Sarah J.; Niemeyer, Wayne D.; Conte, Sean; Montgomery, Daniel D.; Erikson, Gregory S.

2014-09-01

RedXDefense has developed an automated red-light/green-light field presumptive lead test using a sampling pad which can be subsequently processed in a Scanning Electron Microscope for GSR confirmation. The XCAT's sampling card is used to acquire a sample from a suspect's hands on the scene and give investigators an immediate presumptive as to the presence of lead possibly from primer residue. Positive results can be obtained after firing as little as one shot. The same sampling card can then be sent to a crime lab and processed on the SEM for GSR following ASTM E-1588-10 Standard Guide for Gunshot Residue Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry, in the same manner as the existing tape lifts currently used in the field. Detection of GSR-characteristic particles (fused lead, barium, and antimony) as small as 0.8 microns (0.5 micron resolution) has been achieved using a JEOL JSM-6480LV SEM equipped with an Oxford Instruments INCA EDS system with a 50mm2 SDD detector, 350X magnification, in low-vacuum mode and in high vacuum mode after coating with carbon in a sputter coater. GSR particles remain stable on the sampling pad for a minimum of two months after chemical exposure (long term stability tests are in progress). The presumptive result provided by the XCAT yields immediate actionable intelligence to law enforcement to facilitate their investigation, without compromising the confirmatory test necessary to further support the investigation and legal case.

What Every Special Educator Must Know: The International Standards for the Preparation and Certification of Special Education Teachers.

ERIC Educational Resources Information Center

Council for Exceptional Children, Reston, VA.

This document presents standards and guidelines for the preparation and certification of special educators, as identified by the Council for Exceptional Children (CEC), CEC Divisions, and others. Part 1 includes the CEC Code of Ethics and Standards for Professional Practice for Educators of Persons with Exceptionalities. This section provides…

Contaminants of emerging concern in the Great Lakes Basin: A report on sediment, water, and fish tissue chemistry collected in 2010-2012

USGS Publications Warehouse

Choy, Steven J.; Annis, Mandy L.; Banda, JoAnn; Bowman, Sarah R.; Brigham, Mark E.; Elliott, Sarah M.; Gefell, Daniel J.; Jankowski, Mark D.; Jorgenson, Zachary G.; Lee, Kathy E.; Moore, Jeremy N.; Tucker, William A.

2017-01-01

Despite being detected at low levels in surface waters and sediments across the United States, contaminants of emerging concern (CECs) in the Great Lakes Basin are not well characterized in terms of spatial and temporal occurrence. Additionally, although the detrimental effects of exposure to CECs on fish and wildlife have been documented for many CECs in laboratory studies, we do not adequately understand the implications of the presence of CECs in the environment. Based on limited studies using current environmentally relevant concentrations of chemicals, however, risks to fish and wildlife are evident. As a result, there is an increasing urgency to address data gaps that are vital to resource management decisions. The U.S. Fish and Wildlife Service, in collaboration with the U.S. Geological Survey, is leading a Great Lakes Basin-wide evaluation of CECs (CEC Project) with the objectives to (a) characterize the spatial and temporal distribution of CECs; (b) evaluate risks to fish and wildlife resources; and (c) develop tools to aid resource managers in detecting, averting, or minimizing the ecological consequences to fish and wildlife that are exposed to CECs. This report addresses objective (a) of the CEC Project, summarizing sediment and water chemistry data collected from 2010 to 2012 and fish liver tissue chemistry data collected in 2012; characterizes the sampling locations with respect to potential sources of CECs in the landscape; and provides an initial interpretation of the variation in CEC concentrations relative to the identified sources. Data collected during the first three years of our study, which included 12 sampling locations and analysis of 134 chemicals, indicate that contaminants were more frequently detected in sediment compared to water. Chemicals classified as alkyphenols, flavors/ fragrances, hormones, PAHs, and sterols had higher average detection frequencies in sediment compared to water, while the opposite was observed for pesticides

In situ SEM thermal fatigue of Al/graphite metal matrix composites

NASA Technical Reports Server (NTRS)

Zong, G. S.; Rabenberg, L.; Marcus, H. L.

1990-01-01

Several thermal fatigue-induced failure mechanisms are deduced for unidirectional graphite-reinforced 6061 Al-alloy MMCs subjected to in situ thermal cycling. These thermal cycling conditions are representative of MMC service cycles in aerospace environments, where thermal fatigue is primarily associated with changes in the stress states near the interfaces due to coefficient of thermal expansion mismatch between fiber and matrix. This in situ SEM thermal-cycling study clarified such factors affecting MMCs' thermal fatigue as local fiber content and distribution, void volume, fiber stiffness, thermal excursion magnitude, and number of thermal cycles. MMC microfailure modes in thermal fatigue have been deduced.

ANATOMIC VARIATIONS OF HEPATIC ARTERY: A STUDY IN 479 LIVER TRANSPLANTATIONS.

PubMed

Fonseca-Neto, Olival Cirilo Lucena da; Lima, Heloise Caroline de Souza; Rabelo, Priscylla; Melo, Paulo Sérgio Vieira de; Amorim, Américo Gusmão; Lacerda, Cláudio Moura

2017-01-01

ão especialmente importantes no contexto do transplante ortotópico hepático, visto que, além de representar oportunidade ideal para seu estudo anatômico cirúrgico, a sua precisa identificação é determinante para o sucesso do procedimento. Identificar as variações anatômicas no sistema arterial hepático em transplantes hepáticos. Foram analisados retrospectivamente, no período de 13 anos, 479 prontuários de pacientes adultos transplantados, sendo coletados dados referentes à anatomia arterial hepática do doador falecido. Identificou-se anatomia arterial hepática normal em 416 doadores (86,84%). Os outros 63 indivíduos (13,15%) apresentaram alguma variação. De acordo com a classificação de Michels, as anomalias mais frequentes foram: artéria hepática direita ramo da artéria mesentérica superior (Tipo III, n=27, 5,63%); artéria hepática esquerda ramo da artéria gástrica esquerda (Tipo II, n=13, 2,71%); artéria hepática direita ramo da artéria mesentérica superior associada à artéria hepática esquerda ramo da artéria gástrica esquerda (Tipo IV, n=4, 0,83%). Do mesmo modo, em relação à Classificação de Hiatt, as variações mais prevalentes foram: artéria hepática direita acessória ou substituta da artéria mesentérica superior (Tipo III, n=28, 6,05%), seguida da artéria hepática esquerda acessória ou substituta da artéria gástrica esquerda (Tipo II, n=16, 3,34%). Quatorze pessoas (2,92%) apresentaram alterações anatômicas sem classificação definida, sendo a de maior frequência o tronco hepatomesentérico, identificado em cinco (1,04%). O conhecimento detalhado das variações da anatomia arterial hepática é de grande importância aos cirurgiões que realizam abordagens nessa região, em especial no transplante hepático, visto que sua identificação e correto manejo são fundamentais para o êxito do procedimento.

The effect of home bleaching agents on the surface roughness of five different composite resins: A SEM evaluation.

PubMed

Cengiz, Esra; Kurtulmus-Yilmaz, Sevcan; Ulusoy, Nuran; Deniz, Sule Tugba; Yuksel-Devrim, Ece

2016-05-01

The aim of this study was to investigate the effect of hydrogen peroxide (HP) and carbamide peroxide (CP) on the surface roughness of five different composite resins using profilometer and scanning electron microscope (SEM). Thirty-six specimens (1 mm thick, 10 mm in diameter) of five composite resins were fabricated. Each composite group was equally divided into three subgroups as control, CP and HP. In control group, specimens were stored in daily refreshed distilled water during the 14-day testing period. In other groups, 10% HP (Opalescence Treswhite) and 10% CP (Opalescence PF) were applied and surface roughness values (Ra) of each specimen were measured with a profilometer at the end of 14 days. Additionally, SEM analysis was performed to evaluate the surface deformations of composite resins. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Ra values of composite groups exposed to bleaching agents were statistically higher than control group (p < 0.05). There was no significant difference between Ra values after HP and CP application within each composite group while SEM micrographs showed higher surface alterations at HP group compared to CP. Among the composite resins tested, Ceram-X Mono revealed the lowest Ra values after CP and HP applications as seen at SEM images. Home bleaching agents increased the surface roughness of all composites. Except CP applied Ceram-X mono specimens, Ra values of all composite resins evaluated in this study exceeded the critical limit of 0.2 μm. Ceram-X mono was the least affected composite material after bleaching application. SCANNING 38:277-283, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

A Data Matrix Method for Improving the Quantification of Element Percentages of SEM/EDX Analysis

NASA Technical Reports Server (NTRS)

Lane, John

2009-01-01

A simple 2D M N matrix involving sample preparation enables the microanalyst to peer below the noise floor of element percentages reported by the SEM/EDX (scanning electron microscopy/ energy dispersive x-ray) analysis, thus yielding more meaningful data. Using the example of a 2 3 sample set, there are M = 2 concentration levels of the original mix under test: 10 percent ilmenite (90 percent silica) and 20 percent ilmenite (80 percent silica). For each of these M samples, N = 3 separate SEM/EDX samples were drawn. In this test, ilmenite is the element of interest. By plotting the linear trend of the M sample s known concentration versus the average of the N samples, a much higher resolution of elemental analysis can be performed. The resulting trend also shows how the noise is affecting the data, and at what point (of smaller concentrations) is it impractical to try to extract any further useful data.

Signal-to-noise ratio enhancement on SEM images using a cubic spline interpolation with Savitzky-Golay filters and weighted least squares error.

PubMed

Kiani, M A; Sim, K S; Nia, M E; Tso, C P

2015-05-01

A new technique based on cubic spline interpolation with Savitzky-Golay smoothing using weighted least squares error filter is enhanced for scanning electron microscope (SEM) images. A diversity of sample images is captured and the performance is found to be better when compared with the moving average and the standard median filters, with respect to eliminating noise. This technique can be implemented efficiently on real-time SEM images, with all mandatory data for processing obtained from a single image. Noise in images, and particularly in SEM images, are undesirable. A new noise reduction technique, based on cubic spline interpolation with Savitzky-Golay and weighted least squares error method, is developed. We apply the combined technique to single image signal-to-noise ratio estimation and noise reduction for SEM imaging system. This autocorrelation-based technique requires image details to be correlated over a few pixels, whereas the noise is assumed to be uncorrelated from pixel to pixel. The noise component is derived from the difference between the image autocorrelation at zero offset, and the estimation of the corresponding original autocorrelation. In the few test cases involving different images, the efficiency of the developed noise reduction filter is proved to be significantly better than those obtained from the other methods. Noise can be reduced efficiently with appropriate choice of scan rate from real-time SEM images, without generating corruption or increasing scanning time. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

What Every Special Educator Must Know: The International Standards for the Preparation and Certification of Special Education Teachers. Second Edition.

ERIC Educational Resources Information Center

Council for Exceptional Children, Reston, VA.

This document presents revised comprehensive standards and guidelines for the preparation and certification of special educators and for practice as special educators, developed by the Council for Exceptional Children (CEC). Part 1 provides the CEC's Code of Ethics for Professional Practice for Educators of Persons with Exceptionalities and CEC's…

Clinical ethics protocols in the clinical ethics committees of Madrid.

PubMed

Herreros, Benjamin; Ramnath, Venktesh R; Bishop, Laura; Pintor, Emilio; Martín, María Dolores; Sánchez-González, Miguel A

2014-03-01

Currently, The nature and scope of Clinical Ethics Protocols (CEPs) in Madrid (Spain) are not well understood. The main objective is to describe the features of 'guideline/recommendation' type CEPs that have been or are being developed by existing Clinical Ethics Committees (CECs) in Madrid. Secondary objectives include characterisation of those CECs that have been the most prolific in reference to CEP creation and implementation and identification of any trends in future CEP development. We collected CEPs produced and in process by CECs accredited in the public hospitals in Madrid, Spain, from 1996 to 2008. CECs developed 30 CEPs, with 10 more in process. The most common topic is refusal of treatment (seven CEPs developed; two in process). If CEPs addressing terminal illness, Do-Not-Resuscitate orders and advance directives are placed into a separate 'ethical problems at the end of life' category, this CEP subject emerges as the most common (eight developed; four in process). There is a relationship between the age of the CEC and the development of CEPs (the oldest CECs have developed more CEPs). CECs now seem to be more likely to engage in CEP development. The CECs in Madrid, Spain, have developed a significant number of CEPs (30 in total and 10 in process) and there is a trend towards continued development. The most frequent topics are ethical problems at the end of life and refusal of treatment by the patient.

Comparative SEM and LM foliar epidermal and palyno-morphological studies of Amaranthaceae and its taxonomic implications.

PubMed

Hussain, Amara Noor; Zafar, Muhammad; Ahmad, Mushtaq; Khan, Raees; Yaseen, Ghulam; Khan, Muhammad Saleem; Nazir, Abdul; Khan, Amir Muhammad; Shaheen, Shabnum

2018-05-01

Palynological features as well as comparative foliar epidermal using light and scanning electron microscope (SEM) of 17 species (10genera) of Amaranthaceae have been studied for its taxonomic significance. Different foliar and palynological micro-morphological characters were examined to explain their value in resolving the difficulty in identification. All species were amphistomatic but stomata on abaxial surface were more abundant. Taxonomically significant epidermal character including stomata type, trichomes (unicellular, multicellular, and capitate) and epidermal cells shapes (polygonal and irregular) were also observed. Pollens of this family are Polypantoporate, pores large, spheroidal, mesoporous region is sparsely to scabrate, densely psilate, and spinulose. All these characters can be active at species level for identification purpose. This study indicates that at different taxonomic levels, LM and SEM pollen and epidermal morphology is explanatory and significant to identify species and genera. © 2018 Wiley Periodicals, Inc.

Microstructural observation of fuel cell catalyst inks by Cryo-SEM and Cryo-TEM.

PubMed

Shimanuki, Junichi; Takahashi, Shinichi; Tohma, Hajime; Ohma, Atsushi; Ishihara, Ayumi; Ito, Yoshiko; Nishino, Yuri; Miyazawa, Atsuo

2017-06-01

In order to improve the electricity generation performance of fuel cell electric vehicles, it is necessary to optimize the microstructure of the catalyst layer of a polymer electrolyte fuel cell. The catalyst layer is formed by a wet coating process using catalyst inks. Therefore, it is very important to observe the microstructure of the catalyst ink. In this study, the morphology of carbon-supported platinum (Pt/C) particles in catalyst inks with a different solvent composition was investigated by cryogenic scanning electron microscopy (cryo-SEM). In addition, the morphology of the ionomer, which presumably influences the formation of agglomerated Pt/C particles in a catalyst ink, was investigated by cryogenic transmission electron microscopy (cryo-TEM). The results of a cryo-SEM observation revealed that the agglomerated Pt/C particles tended to become coarser with a higher 1-propanol (NPA) weight fraction. The results of a cryo-TEM observation indicated that the actual ionomer dispersion in a catalyst ink formed a network structure different from that of the ionomer in the solvent. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chemical Characterization of Bed Material Coatingsby LA-ICP-MS and SEM-EDS

NASA Astrophysics Data System (ADS)

Piispanen, M. H.; Mustonen, A. J.; Tiainen, M. S.; Laitinen, R. S.

Bed material coatings and the consequent agglomeration of bed material are main ash-related problems in FB-boilers. The bed agglomeration is a particular problem when combusting biofuels and waste materials. Whereas SEM-EDS together with automated image processing has proven to be a convenient method to study compositional distribution in coating layers and agglomerates, it is a relatively expensive technique and is not necessarily widely available. In this contribution, we explore the suitability of LA-ICP-MS to provide analogous information of the bed.

Occurrence, distribution, and seasonality of emerging contaminants in urban watersheds.

PubMed

Bai, Xuelian; Lutz, Alex; Carroll, Rosemary; Keteles, Kristen; Dahlin, Kenneth; Murphy, Mark; Nguyen, David

2018-06-01

The widespread occurrence of natural and synthetic organic chemicals in surface waters can cause ecological risks and human health concerns. This study measured a suite of contaminants of emerging concern (CECs) in water samples collected by the U.S. Environmental Protection Agency Region 8 around the Denver, Colorado, metropolitan area. The results showed that 109 of 144 analyzed pharmaceutical compounds, 42 of 55 analyzed waste-indicator compounds (e.g., flame retardants, hormones, and personal care products), and 39 of 72 analyzed pesticides were detected in the water samples collected monthly between April and November in both 2014 and 2015. Pharmaceutical compounds were most abundant in the surface waters and their median concentrations were measured up to a few hundred nanograms per liter. The CEC concentrations varied depending on sampling locations and seasons. The primary source of CECs was speculated to be wastewater effluent. The CEC concentrations were correlated to streamflow volume and showed significant seasonal effects. The CECs were less persistent during spring runoff season compared with baseflow season at most sampling sites. These results are useful for providing baseline data for surface CEC monitoring and assessing the environmental risks and potential human exposure to CECs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Determinants of HDL Cholesterol Efflux Capacity after Virgin Olive Oil Ingestion: Interrelationships with Fluidity of HDL Monolayer.

PubMed

Fernández-Castillejo, Sara; Rubió, Laura; Hernáez, Álvaro; Catalán, Úrsula; Pedret, Anna; Valls, Rosa-M; Mosele, Juana I; Covas, Maria-Isabel; Remaley, Alan T; Castañer, Olga; Motilva, Maria-José; Solá, Rosa

2017-12-01

Cholesterol efflux capacity of HDL (CEC) is inversely associated with cardiovascular risk. HDL composition, fluidity, oxidation, and size are related with CEC. We aimed to assess which HDL parameters were CEC determinants after virgin olive oil (VOO) ingestion. Post-hoc analyses from the VOHF study, a crossover intervention with three types of VOO. We assessed the relationship of 3-week changes in HDL-related variables after intervention periods with independence of the type of VOO. After univariate analyses, mixed linear models were fitted with variables related with CEC and fluidity. Fluidity and Apolipoprotein (Apo)A-I content in HDL was directly associated, and HDL oxidative status inversely, with CEC. A reduction in free cholesterol, an increase in triglycerides in HDL, and a decrease in small HDL particle number or an increase in HDL mean size, were associated to HDL fluidity. HDL fluidity, ApoA-I concentration, and oxidative status are major determinants for CEC after VOO. The impact on CEC of changes in free cholesterol and triglycerides in HDL, and those of small HDL or HDL mean size, could be mechanistically linked through HDL fluidity. Our work points out novel therapeutic targets to improve HDL functionality in humans through nutritional or pharmacological interventions. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A six-colour flow cytometric method for simultaneous detection of cell phenotype and apoptosis of circulating endothelial cells.

PubMed

Mariucci, S; Rovati, B; Chatzileontiadou, S; Bencardino, K; Manzoni, M; Delfanti, S; Danova, M

2009-01-01

Blood circulating endothelial cells (CECs), with their resting and activated subsets, (rCECs and aCECs) and circulating progenitors cells (CEPs) are two extremely rare cell populations that are important in tissue vascularization. Their number and function are modulated in diseases involving vascular injury, such as human tumours. Although a consensus on the phenotypic definition of endothelial cells, as well as on the optimal enumeration technique, is still lacking, the number of clinical studies based on assessment of these cells is rapidly expanding, as well as the analytical methods employed. The present study aimed to develop a rapid and sensitive flow cytometric method of quantifying and characterizing CECs (with both their subsets and the apoptotic fraction) and CEPs. We analysed peripheral blood samples from 21 subjects with a six-colour flow cytometric approach allowing detection of the cell phenotype of CECs and CEPs using a monoclonal antibodies panel and a dedicated gating strategy. Apoptotic CECs were detected with Annexin V and dead cells with 7-amino-actinomycin D staining. The described technique proved to be a new, reliable, tool increasing our knowledge of the biology of CECs and CEPs and can readily be applied in the study of many pathological conditions characterized by endothelial damage.

Comparison of cefuroxime axetil, cefaclor, and amoxicillin-clavulanate potassium suspensions in acute otitis media in infants and children.

PubMed

Pichichero, M; Aronovitz, G H; Gooch, W M; McLinn, S E; Maddern, B; Johnson, C; Darden, P M

1990-10-01

In this randomized, blinded, multicenter comparison study, 377 infants and children with acute otitis media (AOM) received a 10-day course of an oral suspension of one of the following: cefuroxime axetil (CAE), 30 mg/kg/day; cefaclor (CEC), 40 mg/kg/day; or amoxicillin-clavulanate potassium (AMX-CL), 40 mg/kg/day. Clinical efficacy was determined by pneumatic otoscopy and tympanometric testing 3 to 5, 11 to 14, and 22 to 26 days after the initiation of therapy. There was a statistically significant difference among the three treatment groups with respect to clinical outcome; more patients in the CAE group (62%) than in the CEC group (46%) or the AMX-CL group (52%) had complete resolution of signs and symptoms of AOM (including effusion). Paired comparisons revealed a significant difference in efficacy between CAE and CEC and a nearly significant difference between AMX-CL and CEC. Taste acceptability was highest for CEC and lowest for this formulation of CAE. Significantly more patients in the AMX-CL group than in the CAE or CEC group had a side effect, primarily diarrhea, vomiting, or diaper rash. We conclude that CAE suspension has greater clinical efficacy than CEC and fewer side effects than AMX-CL.

The effects of Rho-associated kinase inhibitor Y-27632 on primary human corneal endothelial cells propagated using a dual media approach.

PubMed

Peh, Gary S L; Adnan, Khadijah; George, Benjamin L; Ang, Heng-Pei; Seah, Xin-Yi; Tan, Donald T; Mehta, Jodhbir S

2015-03-16

The global shortage of donor corneas has garnered extensive interest in the development of graft alternatives suitable for endothelial keratoplasty using cultivated primary human corneal endothelial cells (CECs). We have recently described a dual media approach for the propagation of human CECs. In this work, we characterize the effects of a Rho-kinase inhibitor Y-27632 on the cultivation of CECs propagated using the dual media culture system. Seventy donor corneas deemed unsuitable for transplantation were procured for this study. We assessed the use of Y-27632 for its effect at each stage of the cell culture process, specifically for cell attachment, cell proliferation, and during both regular passaging and cryopreservation. Lastly, comparison of donor-matched CEC-cultures expanded with or without Y-27632 was also performed. Our results showed that Y-27632 significantly improved the attachment and proliferation of primary CECs. A non-significant pro-survival effect was detected during regular cellular passage when CECs were pre-treated with Y-27632, an effect that became more evident during cryopreservation. Our study showed that the inclusion of Y-27632 was beneficial for the propagation of primary CECs expanded via the dual media approach, and was able to increase overall cell yield by between 1.96 to 3.36 fold.

Distinction between amorphous and healed planar deformation features in shocked quartz using composite color scanning electron microscope cathodoluminescence (SEM-CL) imaging

NASA Astrophysics Data System (ADS)

Hamers, Maartje F.; Pennock, Gill M.; Herwegh, Marco; Drury, Martyn R.

2016-10-01

Planar deformation features (PDFs) in quartz are one of the most reliable and most widely used forms of evidence for hypervelocity impact. PDFs can be identified in scanning electron microscope cathodoluminescence (SEM-CL) images, but not all PDFs show the same CL behavior: there are nonluminescent and red luminescent PDFs. This study aims to explain the origin of the different CL emissions in PDFs. Focused ion beam (FIB) thin foils were prepared of specific sample locations selected in composite color SEM-CL images and were analyzed in a transmission electron microscope (TEM). The FIB preparation technique allowed a direct, often one-to-one correlation between the CL images and the defect structure observed in TEM. This correlation shows that composite color SEM-CL imaging allows distinction between amorphous PDFs on one hand and healed PDFs and basal Brazil twins on the other: nonluminescent PDFs are amorphous, while healed PDFs and basal Brazil twins are red luminescent, with a dominant emission peak at 650 nm. We suggest that the red luminescence is the result of preferential beam damage along dislocations, fluid inclusions, and twin boundaries. Furthermore, a high-pressure phase (possibly stishovite) in PDFs can be detected in color SEM-CL images by its blue luminescence.

Bioactive contaminants of emerging concern in National Park waters of the northern Colorado Plateau, USA.

PubMed

Weissinger, Rebecca H; Blackwell, Brett R; Keteles, Kristen; Battaglin, William A; Bradley, Paul M

2018-05-02

Pharmaceuticals and personal care products (PPCPs), wastewater indicators (WWIs), and pesticides (herein, Contaminants of Emerging Concern [CECs]) have been documented in surface waters throughout the world and have associated risks to aquatic life. While much research has focused on temperate and urbanized watersheds, less is known about CEC presence in semi-arid landscapes, where water availability is limited and populations are low. CEC presence in water and sediment is reported for 21 sites in eight U.S. national parks in the northern Colorado Plateau region. From 2012 to 2016, at least one PPCP and/or WWI was detected at most sites on over half of sampling visits, indicating that CECs are not uncommon even in isolated areas. CEC detections were generally fewer and at lower concentrations than in urbanized or agricultural watersheds. Consistent with studies from other U.S. regions, the most frequently detected CECs in this study include DEET, caffeine, organophosphorus flame retardants, and bisphenol A in water and fecal indicators and polycyclic aromatic hydrocarbons in sediment. Maximum concentrations in this study were generally below available water quality benchmarks, sediment quality guidelines, and risk assessment thresholds associated with vertebrates. Additional work is needed to assess the potential activity of hormones, which had high reporting limits in our study, and potential bioactivity of environmental concentrations for invertebrates, microbial communities, and algae. Potential sources of CEC contamination include upstream wastewater effluent discharges and National Park Service invasive-plant-control herbicide applications. CEC occurrence patterns and similarities between continuous and isolated flow locations suggest that direct contamination from individual visitors may also occur. While our data indicate there is little aquatic health risk associated with CECs at our sites, our results demonstrate the ubiquity of CECs on the landscape and a

Microfluidic assay of circulating endothelial cells in coronary artery disease patients with angina pectoris.

PubMed

Chen, Shuiyu; Sun, Yukun; Neoh, Kuang Hong; Chen, Anqi; Li, Weiju; Yang, Xiaorui; Han, Ray P S

2017-01-01

Circulating endothelial cells (CECs) are widely reported as a promising biomarker of endothelial damage/dysfunction in coronary artery disease (CAD). The two popular methods of CEC quantification include the use of immunomagnetic beads separation (IB) and flow cytometry analysis (FC); however, they suffer from two main shortcomings that affect their diagnostic and prognostic responses: non-specific bindings of magnetic beads to non-target cells and a high degree of variability in rare cell identification, respectively. We designed a microfluidic chip with spatially staggered micropillars for the efficient harvesting of CECs with intact cellular morphology in an attempt to revisit the diagnostic goal of CEC counts in CAD patients with angina pectoris. A label-free microfluidic assay that involved an in-situ enumeration and immunofluorescent identification (DAPI+/CD146+/VEGFR1+/CD45-) of CECs was carried out to assess the CEC count in human peripheral blood samples. A total of 55 CAD patients with angina pectoris [16 with chronic stable angina (CSA) and 39 with unstable angina (UA)], together with 15 heathy controls (HCs) were enrolled in the study. CEC counts are significantly higher in both CSA and UA groups compared to the HC group [respective medians of 6.9, 10.0 and 1.5 cells/ml (p < 0.01)]. Further, a significant elevation of CEC count was observed in the three UA subgroups [low risk (5.3) vs. intermediate risk (10.8) vs. high risk (18.0) cells/ml, p < 0.001) classified in accordance to the TIMI NSTEMI/UA risk score system. From the receiver-operating characteristic curve analysis, the AUCs for distinguishing CSA and UA from HC were 0.867 and 0.938, respectively. The corresponding sensitivities were 87.5% and 84.6% and the specificities were 66.7% and 86.7%, respectively. Our microfluidic assay system is efficient and stable for CEC capture and enumeration. The results showed that the CEC count has the potential to be a promising clinical biomarker for the

Quantification of circulating mature endothelial cells using a whole blood four-color flow cytometric assay.

PubMed

Jacques, Nathalie; Vimond, Nadege; Conforti, Rosa; Griscelli, Franck; Lecluse, Yann; Laplanche, Agnes; Malka, David; Vielh, Philippe; Farace, Françoise

2008-09-15

Circulating endothelial cells (CEC) are currently proposed as a potential biomarker for measuring the impact of anti-angiogenic treatments in cancer. However, the lack of consensus on the appropriate method of CEC measurement has led to conflicting data in cancer patients. A validated assay adapted for evaluating the clinical utility of CEC in large cohorts of patients undergoing anti-angiogenic treatments is needed. We developed a four-color flow cytometric assay to measure CEC as CD31(+), CD146(+), CD45(-), 7-amino-actinomycin-D (7AAD)(-) events in whole blood. The distinctive features of the assay are: (1) staining of 1 ml whole blood, (2) use of a whole blood IgPE control to measure accurately background noise, (3) accumulation of a large number of events (almost 5 10(6)) to ensure statistical analysis, and (4) use of 10 microm fluorescent microbeads to evaluate the event size. Assay reproducibility was determined in duplicate aliquots of samples drawn from 20 metastatic cancer patients. Assay linearity was tested by spiking whole blood with low numbers of HUVEC. Five-color flow cytometric experiments with CD144 were performed to confirm the endothelial origin of the cells. CEC were measured in 20 healthy individuals and 125 patients with metastatic cancer. Reproducibility was good between duplicate aliquots (r(2)=0.948, mean difference between duplicates of 0.86 CEC/ml). Detected HUVEC correlated with spiked HUVEC (r(2)=0.916, mean recovery of 100.3%). Co-staining of CD31, CD146 and CD144 confirmed the endothelial nature of cells identified as CEC. Median CEC levels were 6.5/ml (range, 0-15) in healthy individuals and 15.0/ml (range, 0-179) in patients with metastatic carcinoma (p<0.001). The assay proposed here allows reproducible and sensitive measurement of CEC by flow cytometry and could help evaluate CEC as biomarkers of anti-angiogenic therapies in large cohorts of patients.

Automated SEM Modal Analysis Applied to the Diogenites

NASA Technical Reports Server (NTRS)

Bowman, L. E.; Spilde, M. N.; Papike, James J.

1996-01-01

Analysis of volume proportions of minerals, or modal analysis, is routinely accomplished by point counting on an optical microscope, but the process, particularly on brecciated samples such as the diogenite meteorites, is tedious and prone to error by misidentification of very small fragments, which may make up a significant volume of the sample. Precise volume percentage data can be gathered on a scanning electron microscope (SEM) utilizing digital imaging and an energy dispersive spectrometer (EDS). This form of automated phase analysis reduces error, and at the same time provides more information than could be gathered using simple point counting alone, such as particle morphology statistics and chemical analyses. We have previously studied major, minor, and trace-element chemistry of orthopyroxene from a suite of diogenites. This abstract describes the method applied to determine the modes on this same suite of meteorites and the results of that research. The modal abundances thus determined add additional information on the petrogenesis of the diogenites. In addition, low-abundance phases such as spinels were located for further analysis by this method.

SEM/EDS Characterization of Ambient PM during Agricultural Burns

NASA Astrophysics Data System (ADS)

Wagner, J.; Wall, S.

2010-12-01

Ambient particulate matter (PM) samples were collected with UNC passive samplers during agricultural burns in Imperial Valley, California. Four Bermuda grass field burn events were sampled at 3-8 locations surrounding each burn. Sampling began at the start of each burn (30-60 min) and continued for 24-120 hours. During 3 of the 4 burn events, winds were calm and plumes were observed to travel straight up to the inversion layer. In one event, winds created a ground-level plume that enveloped two UNC samplers mounted on telephone poles very close to the field (0.2-0.3 miles away). Computer-controlled scanning electron microscopy / energy-dispersive x-ray spectroscopy (CCSEM/EDS) was used to measure particle sizes and elemental composition, from which mass concentrations and size distributions were calculated. The median PM2.5 and PM10 levels measured in this study were 3.4 and 20 ug/m3, respectively. To determine quantitative accuracy, UNC sampler PM2.5 results (PM< 2.5 um) were compared to PM2.5 results from four co-located, continuous-reading beta-attenuation monitors (EBAMs). The median agreement (EBAM - UNC) was 3.8 ug/m3. Manual SEM/EDS detected various distinctive species in these samples, including sea salt, spores, plant fragments, and large soot agglomerates. During the ‘plume event’, 24-hour PM2.5 exposures downwind were up to 17 times higher than that measured upwind. Numerous submicron combustion particles with carbon and oxygen only were directly observed by manual SEM/EDS in the two plume-impacted samples, along with larger ash particles enriched in potassium, sulfur, chlorine, calcium, sodium, and phosphorus. CCSEM/EDS data from this event was grouped into 5 particle classes to generate size-fraction-specific pie charts. Burn-related particle types contributed 95% of the PM2.5 in the location directly impacted by the ground-level plume, compared to only 12% in the upwind location. A sample of Imperial County Bermuda grass analyzed in bulk and

30 CFR 250.1912 - What criteria for management of change must my SEMS program meet?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 2 2011-07-01 2011-07-01 false What criteria for management of change must my SEMS program meet? 250.1912 Section 250.1912 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT..., health, and the coastal and marine environments; (3) Necessary time period to implement the change; and...

Landfill leachate as a mirror of today's disposable society: Pharmaceuticals and other contaminants of emerging concern in final leachate from landfills in the conterminous United States

USGS Publications Warehouse

Masoner, Jason R.; Kolpin, Dana W.; Furlong, Edward T.; Cozzarelli, Isabelle M.; Gray, James L.

2015-01-01

Final leachates (leachate after storage or treatment processes) from 22 landfills in 12 states were analyzed for 190 pharmaceuticals and other contaminants of emerging concern (CECs), which were detected in every sample, with the number of CECs ranging from 1 to 58 (median = 22). In total, 101 different CECs were detected in leachate samples, including 43 prescription pharmaceuticals, 22 industrial chemicals, 15 household chemicals, 12 nonprescription pharmaceuticals, 5 steroid hormones, and 4 animal/plant sterols. The most frequently detected CECs were lidocaine (91%, local anesthetic), cotinine (86%, nicotine degradate), carisoprodol (82%, muscle relaxant), bisphenol A (77%, component of plastics and thermal paper), carbamazepine (77%, anticonvulsant), and N,N-diethyltoluamide (68%, insect repellent). Concentrations of CECs spanned 7 orders of magnitude, ranging from 2.0 ng/L (estrone) to 17 200 000 ng/L (bisphenol A). Concentrations of household and industrial chemicals were the greatest (∼1000-1 000 000 ng/L), followed by plant/animal sterols (∼1000-100 000 ng/L), nonprescription pharmaceuticals (∼100-10 000 ng/L), prescription pharmaceuticals (∼10-10 000 ng/L), and steroid hormones (∼10-100 ng/L). The CEC concentrations in leachate from active landfills were significantly greater than those in leachate from closed, unlined landfills (p = 0.05). The CEC concentrations were significantly greater (p < 0.01) in untreated leachate compared with treated leachate. The CEC concentrations were significantly greater in leachate disposed to wastewater treatment plants from modern lined landfills than in leachate released to groundwater from closed, unlined landfills (p = 0.04). The CEC concentrations were significantly greater (p = 0.06) in the fresh leachate (leachate before storage or treatment) reported in a previous study compared with the final leachate sampled for the present study.

Bombyx mori cecropin A has a high antifungal activity to entomopathogenic fungus Beauveria bassiana.

PubMed

Lu, Dingding; Geng, Tao; Hou, Chengxiang; Huang, Yuxia; Qin, Guangxing; Guo, Xijie

2016-05-25

A cDNA encoding cecropin A (CecA) was cloned from the larvae of silkworm, Bombyx mori, using RT-PCR. It encodes a protein of 63 amino acids, containing a 22 amino acid signal peptide and a 37 amino acid mat peptide of functional domain. The CecA secondary structure contains two typical amphiphilic α-helices. Real-time qPCR analysis revealed that CecA was expressed in all the tissues tested, including cuticle, fat body, hemocytes, Malpighian tubule, midgut and silk gland in the silkworm larvae with the highest expression in the fat body and hemocytes. The gene expression of B. mori CecA was rapidly induced by Beauveria bassiana challenge and reached maximum levels at 36h after inoculation in third instar larvae. In the fifth instar larvae infected with B. bassiana, the relative expression level of CecA was upregulated in fat body and hemocytes, but not in cuticle, Malpighian tubule, midgut and silk gland. The cDNA segment of the CecA was inserted into the expression plasmid pET-30a(+) to construct a recombinant expression plasmid. Western blot results revealed that his-tagged fusion protein was successfully expressed and purified. Then the mat peptide of CecA was chemically synthesized with C-terminus amidation for in vivo antifungal assay and purity achieved 93.7%. Mass spectrometry and SDS-PAGE showed its molecular weight to be 4046.95Da. Antifungal assays indicated that the B. mori CecA had a high antifungal activity to entomopathogenic fungus B. bassiana both in vitro and in vivo in the silkworm larvae. This is the first report that the CecA is effective to inhibit B. bassiana inside the body of silkworm. Copyright © 2016 Elsevier B.V. All rights reserved.

Different cytokine response of primary colonic epithelial cells to commensal bacteria.

PubMed

Lan, Jing-Gang; Cruickshank, Sheena-Margaret; Singh, Joy-Carmelina-Indira; Farrar, Mark; Lodge, James-Peter-Alan; Felsburg, Peter-John; Carding, Simon-Richard

2005-06-14

To determine if primary murine colonic epithelial cells (CEC) respond to commensal bacteria and discriminate between different types of bacteria. A novel CEC: bacteria co-culture system was used to compare the ability of the colonic commensal bacteria, Bacteroides ovatus, E. coli (SLF) and Lactobacillus rhamnosus (LGG) to modulate production of different cytokines (n = 15) by primary CEC. Antibody staining and flow cytometry were used to investigate Toll-like receptor (TLR) expression by CEC directly ex vivo and TLR responsiveness was determined by examining the ability of TLR ligands to influence CEC cytokine production. Primary CEC constitutively expressed functional TLR2 and TLR4. Cultured in complete medium alone, CEC secreted IL-6, MCP-1 and IP-10 the levels of which were significantly increased upon addition of the TLR ligands peptidoglycan (PGN) and lipopolysaccharide (LPS). Exposure to the commensal bacteria induced or up-regulated different patterns of cytokine production and secretion. E. coli induced production of MIP-1alpha/beta and betadefensin3 whereas B. ovatus and L. rhamnosus exclusively induced MCP-1 and MIP-2alpha expression, respectively. TNFalpha, RANTES and MEC were induced or up-regulated in response to some but not all of the bacteria whereas ENA78 and IP-10 were up-regulated in response to all bacteria. Evidence of bacterial interference and suppression of cytokine production was obtained from mixed bacterial: CEC co-cultures. Probiotic LGG suppressed E. coli- and B. ovatus-induced cytokine mRNA accumulation and protein secretion. These observations demonstrate the ability of primary CEC to respond to and discriminate between different strains of commensal bacteria and identify a mechanism by which probiotic bacteria (LGG) may exert anti-inflammatory effects in vivo.

Different cytokine response of primary colonic epithelial cells to commensal bacteria

PubMed Central

Lan, Jing-Gang; Cruickshank, Sheena Margaret; Singh, Joy Carmelina Indira; Farrar, Mark; Lodge, James Peter Alan; Felsburg, Peter John; Carding, Simon Richard

2005-01-01

AIM: To determine if primary murine colonic epithelial cells (CEC) respond to commensal bacteria and discriminate between different types of bacteria. METHODS: A novel CEC: bacteria co-culture system was used to compare the ability of the colonic commensal bacteria, Bacteroides ovatus, E. coli (SLF) and Lactobacillus rhamnosus (LGG) to modulate production of different cytokines (n = 15) by primary CEC. Antibody staining and flow cytometry were used to investigate Toll-like receptor (TLR) expression by CEC directly ex vivo and TLR responsiveness was determined by examining the ability of TLR ligands to influence CEC cytokine production. RESULTS: Primary CEC constitutively expressed functional TLR2 and TLR4. Cultured in complete medium alone, CEC secreted IL-6, MCP-1 and IP-10 the levels of which were significantly increased upon addition of the TLR ligands peptidoglycan (PGN) and lipopolysaccharide (LPS). Exposure to the commensal bacteria induced or up-regulated different patterns of cytokine production and secretion. E. coli induced production of MIP-1α/β and β defensin3 whereas B. ovatus and L. rhamnosus exclusively induced MCP-1 and MIP-2α expression, respectively. TNFα, RANTES and MEC were induced or up-regulated in response to some but not all of the bacteria whereas ENA78 and IP-10 were up-regulated in response to all bacteria. Evidence of bacterial interference and suppression of cytokine production was obtained from mixed bacterial: CEC co-cultures. Probiotic LGG suppressed E. coli- and B. ovatus-induced cytokine mRNA accumulation and protein secretion. CONCLUSION: These observations demonstrate the ability of primary CEC to respond to and discriminate between different strains of commensal bacteria and identify a mechanism by which probiotic bacteria (LGG) may exert anti-inflammatory effects in vivo. PMID:15948242

Landfill leachate as a mirror of today's disposable society: Pharmaceuticals and other contaminants of emerging concern in final leachate from landfills in the conterminous United States.

PubMed

Masoner, Jason R; Kolpin, Dana W; Furlong, Edward T; Cozzarelli, Isabelle M; Gray, James L

2016-04-01

Final leachates (leachate after storage or treatment processes) from 22 landfills in 12 states were analyzed for 190 pharmaceuticals and other contaminants of emerging concern (CECs), which were detected in every sample, with the number of CECs ranging from 1 to 58 (median = 22). In total, 101 different CECs were detected in leachate samples, including 43 prescription pharmaceuticals, 22 industrial chemicals, 15 household chemicals, 12 nonprescription pharmaceuticals, 5 steroid hormones, and 4 animal/plant sterols. The most frequently detected CECs were lidocaine (91%, local anesthetic), cotinine (86%, nicotine degradate), carisoprodol (82%, muscle relaxant), bisphenol A (77%, component of plastics and thermal paper), carbamazepine (77%, anticonvulsant), and N,N-diethyltoluamide (68%, insect repellent). Concentrations of CECs spanned 7 orders of magnitude, ranging from 2.0 ng/L (estrone) to 17,200,000 ng/L (bisphenol A). Concentrations of household and industrial chemicals were the greatest (∼1000-1,000,000 ng/L), followed by plant/animal sterols (∼1000-100,000 ng/L), nonprescription pharmaceuticals (∼100-10,000 ng/L), prescription pharmaceuticals (∼10-10,000 ng/L), and steroid hormones (∼10-100 ng/L). The CEC concentrations in leachate from active landfills were significantly greater than those in leachate from closed, unlined landfills (p = 0.05). The CEC concentrations were significantly greater (p < 0.01) in untreated leachate compared with treated leachate. The CEC concentrations were significantly greater in leachate disposed to wastewater treatment plants from modern lined landfills than in leachate released to groundwater from closed, unlined landfills (p = 0.04). The CEC concentrations were significantly greater (p = 0.06) in the fresh leachate (leachate before storage or treatment) reported in a previous study compared with the final leachate sampled for the present study. Published 2015 SETAC. This article is a US Government work and as such

An Analysis of the Adult Education Curricula Implemented in Turkish Universities

ERIC Educational Resources Information Center

Selvi, Kiymet; Baldan, Betül; Alagöz, Yaprak

2016-01-01

The aim of the study to examine the characteristics of the programs conducted by the Continuing Education Centers (CECs), to reveal whether these programs serve for equality, and to identify the institutional barriers related to the CEC programs against adult education. CECs aim to fulfill the educational needs of adults and/or sectors in…

Using Delft3D to Simulate Current Energy Conversion

NASA Astrophysics Data System (ADS)

James, S. C.; Chartrand, C.; Roberts, J.

2015-12-01

As public concern with renewable energy increases, current energy conversion (CEC) technology is being developed to optimize energy output and minimize environmental impact. CEC turbines generate energy from tidal and current systems and create wakes that interact with turbines located downstream of a device. The placement of devices can greatly influence power generation and structural reliability. CECs can also alter the ecosystem process surrounding the turbines, such as flow regimes, sediment dynamics, and water quality. Software is needed to investigate specific CEC sites to simulate power generation and hydrodynamic responses of a flow through a CEC turbine array. This work validates Delft3D against several flume experiments by simulating the power generation and hydrodynamic response of flow through a turbine or actuator disc(s). Model parameters are then calibrated against these data sets to reproduce momentum removal and wake recovery data with 3-D flow simulations. Simulated wake profiles and turbulence intensities compare favorably to the experimental data and demonstrate the utility and accuracy of a fast-running tool for future siting and analysis of CEC arrays in complex domains.

SEM evaluation of pulp reaction to different pulp capping materials in dog’s teeth

PubMed Central

Asgary, Saeed; Parirokh, Masoud; Eghbal, Mohammad Jafar; Ghoddusi, Jamileh

2006-01-01

Introduction: This investigation evaluates the effects of mineral trioxide aggregate (MTA), calcium hydroxide (CH) and calcium enriched mixture (CEM) as pulp capping materials on dental pulp tissues. Materials and Methods: The experimental procedures were performed on eighteen intact dog canine teeth. The pulps were exposed. Cavities were randomly filled with CEM, MTA, or CH followed by glass ionomer filling. After 2 months, animals were sacrificed, each tooth was sectioned into halves, and the interface between each capping material and pulp tissue was evaluated by scanning electron microscope (SEM) in profile view of the specimens. Results: Dentinal bridge formation as the most characteristic reaction was resulted from SEM observation in all examined groups. Odontoblast-like cells were formed and create dens collagen network, which was calcified gradually by deposition of calcosphirit structures to form newly dentinal bridge. Conclusion: Based on the results of this in vivo study, it was concluded that these test materials are able to produce calcified tissue in underlying pulp in the case of being used as a pulp capping agent. Additionally, it appears that CEM has the potential to be used as a direct pulp capping material during vital pulp therapy. PMID:24379876

Lessons Learned from My Students: The Impact of SEM Teaching and Learning on Affective Development

ERIC Educational Resources Information Center

Hebert, Thomas P.

2010-01-01

Through reflection on his years as an enrichment teacher in Schoolwide Enrichment Model (SEM) programs, the author describes significant ways the social and emotional development of his students was shaped by their involvement in enriched teaching and learning. Through portraits of his students engaged in Type II and Type III enrichment, the…

Chronic exertional compartment syndrome of the superficial posterior compartment: Soleus syndrome.

PubMed

Gross, Christopher E; Parekh, Bela J; Adams, Samuel B; Parekh, Selene G

2015-01-01

Chronic exertional compartment syndrome (CECS) represents the second most-common cause of exertional leg pain with incidence of 27-33%. CECS of the superficial posterior compartment, or soleus syndrome, is rare and has only been discussed briefly in the literature. We discuss the management of two patients with bilateral soleus syndrome or CECS of the superficial posterior compartment.

C-reactive protein induces release of both endothelial microparticles and circulating endothelial cells in vitro and in vivo: further evidence of endothelial dysfunction.

PubMed

Devaraj, Sridevi; Kumaresan, Pappanaicken R; Jialal, Ishwarlal

2011-12-01

Inflammation is pivotal in atherosclerosis. A key early event in atherosclerosis is endothelial dysfunction. C-reactive protein (CRP), the prototypic marker of inflammation in humans, is a risk marker for cardiovascular disease, and there is mounting evidence to support its role in atherothrombosis. CRP has been shown to promote endothelial dysfunction both in vitro and in vivo. Emerging biomarkers of endothelial dysfunction include circulating endothelial cells (CECs) and endothelial microparticles (EMPs). However, there is a paucity of data examining the effect of CRP on CEC and EMP production in vitro and in vivo. In this report, we treated human aortic endothelial cells (HAECs) with increasing concentrations of CRP (0-50 μg/mL) or boiled CRP. We counted CECs and EMPs by flow cytometry. Although CRP treatment resulted in a significant increase in release of both CECs and EMPs, boiled CRP failed to have an effect. Pretreatment of HAECs with sepiapterin or diethylenetriamine NONOate, both of which preserve nitric oxide (NO), resulted in attenuation of CRP's effects on CECs and EMPs. CD32 and CD64 blocking antibodies but not CD16 antibody or lectin-like oxidized LDL receptor 1 small interfering RNA (LOX-1 siRNA) prevented CRP-induced production of CECs and EMPs. Furthermore, delivery of human CRP to Wistar rats compared with human serum albumin resulted in significantly increased CECs and EMPs, corroborating the in vitro findings. We provide novel data that CRP, via NO deficiency, promotes endothelial dysfunction by inducing release of CECs and EMPs, which are biomarkers of endothelial dysfunction.

Cecropins as a marker of Spodoptera frugiperda immunosuppression during entomopathogenic bacterial challenge.

PubMed

Duvic, B; Jouan, V; Essa, N; Girard, P-A; Pagès, S; Abi Khattar, Z; Volkoff, N-A; Givaudan, A; Destoumieux-Garzon, D; Escoubas, J-M

2012-06-01

An antimicrobial peptide (AMP) of the cecropin family was isolated by HPLC from plasma of the insect pest, Spodoptera frugiperda. Its molecular mass is 3910.9 Da as determined by mass spectrometry. Thanks to the EST database Spodobase, we were able to describe 13 cDNAs encoding six different cecropins which belong to the sub-families CecA, CecB, CecC and CecD. The purified peptide identified as CecB1 was chemically synthesized (syCecB1). It was shown to be active against Gram-positive and Gram-negative bacteria as well as fungi. Two closely related entomopathogenic bacteria, Xenorhabdus nematophila F1 and Xenorhabdus mauleonii VC01(T) showed different susceptibility to syCecB1. Indeed, X. nematophila was sensitive to syCecB1 whereas X. mauleonii had a minimal inhibitory concentration (MIC) eight times higher. Interestingly, injection of live X. nematophila into insects did not induce the expression of AMPs in hemolymph. This effect was not observed when this bacterium was heat-killed before injection. On the opposite, both live and heat-killed X. mauleonii induced the expression of AMPs in the hemolymph of S. frugiperda. The same phenomenon was observed for another immune-related protein lacking antimicrobial activity. Altogether, our data suggest that Xenorhabdus strains have developed different strategies to supplant the humoral defense mechanisms of S. frugiperda, either by increasing their resistance to AMPs or by preventing their expression during such host-pathogen interaction. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mitochondrial transfer of mesenchymal stem cells effectively protects corneal epithelial cells from mitochondrial damage.

PubMed

Jiang, Dan; Gao, Fei; Zhang, Yuelin; Wong, David Sai Hung; Li, Qing; Tse, Hung-Fat; Xu, Goufeng; Yu, Zhendong; Lian, Qizhou

2016-11-10

Recent studies have demonstrated that mesenchymal stem cells (MSCs) can donate mitochondria to airway epithelial cells and rescue mitochondrial damage in lung injury. We sought to determine whether MSCs could donate mitochondria and protect against oxidative stress-induced mitochondrial dysfunction in the cornea. Co-culturing of MSCs and corneal epithelial cells (CECs) indicated that the efficiency of mitochondrial transfer from MSCs to CECs was enhanced by Rotenone (Rot)-induced oxidative stress. The efficient mitochondrial transfer was associated with increased formation of tunneling nanotubes (TNTs) between MSCs and CECs, tubular connections that allowed direct intercellular communication. Separation of MSCs and CECs by a transwell culture system revealed no mitochiondrial transfer from MSCs to CECs and mitochondrial function was impaired when CECs were exposed to Rot challenge. CECs with or without mitochondrial transfer from MSCs displayed a distinct survival capacity and mitochondrial oxygen consumption rate. Mechanistically, increased filopodia outgrowth in CECs for TNT formation was associated with oxidative inflammation-activated NFκB/TNFαip2 signaling pathways that could be attenuated by reactive oxygen species scavenger N-acetylcysteine (NAC) treatment. Furthermore, MSCs grown on a decellularized porcine corneal scaffold were transplanted onto an alkali-injured eye in a rabbit model. Enhanced corneal wound healing was evident following healthy MSC scaffold transplantation. And transferred mitochondria was detected in corneal epithelium. In conclusion, mitochondrial transfer from MSCs provides novel protection for the cornea against oxidative stress-induced mitochondrial damage. This therapeutic strategy may prove relevant for a broad range of mitochondrial diseases.

Circulating endothelial cells in acute ischaemic stroke.

PubMed

Nadar, Sunil K; Lip, Gregory Y H; Lee, Kaeng W; Blann, Andrew D

2005-10-01

Increased numbers of CD146-bearing circulating endothelial cells (CECs) in the peripheral blood probably represent the most direct evidence of endothelial cell damage. As acute ischaemic strokes are associated with endothelial abnormalities, we hypothesised that these CECs are raised in acute stroke, and that they would correlate with the other indices of endothelial perturbation, i.e. plasma von Willebrand factor (vWf) and soluble E-selectin. We studied 29 hypertensive patients (19 male; mean age 63 years) who presented with an acute stroke and compared them with 30 high risk hypertensive patients (21 male; mean age 62 years) and 30 normotensive controls (16 male; mean age 58 years). CECs were estimated by CD146 immunobead capture, vWf and soluble E-selectin by ELISA. Patients with an acute ischaemic stroke had significantly higher numbers of CECs/ml of blood (p<0.001) plasma vWf (p=0.008) soluble E-selectin (p=0.002) and higher systolic blood pressure (SBP) as compared to the other groups. The number of CECs significantly correlated with soluble E-selectin (r=0.432, p<0.001) and vWf (r=0.349, p=0.001) but not with SBP (r=0.198, p=0.069). However, in multivariate analysis, only disease group (i.e. health, hypertension or stroke) was associated with increased CECs. Acute ischaemic stroke is associated with increased numbers of CECs. The latter correlate well with established plasma markers of endothelial dysfunction or damage, thus unequivocally confirming severe vasculopathy in this condition. However, the greatest influence on CECs numbers was clinical group.

Influence of the organic complex concentration on adsorption of herbicide in organic modified montmorillonite

NASA Astrophysics Data System (ADS)

Kaludjerovic, Lazar; Tomic, Zorica; Djurovic, Rada; Milosevic, Maja

2016-04-01

Pesticides are recognized as an important source of potential pollution to soil and water due to their mobility and degradation in soils. Results presented in this paper show impact of the organic complex concentration on the adsorption of herbicides (acetochlor) at the surface of the organic modified montmorillonite. In this work, natural montmorillonite from Bogovina, located near Boljevac municipality, was used for organic modification. Cation-exchange capacity of this montmorillonite was determined by extraction with ammonium acetate (86 mmol/100g of clay). Montmorillonite have been modified first with NaCl and than with two organic complexes, hexadecyltrimethylammonium bromide (HDTMA) and phenyltrimethylammonium chloride (PTMA). For both organic complexes, three saturation concentrations were selected for monitoring of the herbicide adsorption (43 mmol/100g of clay (0.5 CEC), 86 mmol/100g of clay (1 CEC) and 129 mmol/100g of clay (1.5 CEC)). Changes in the properties of the inorganic and organic bentonite have been examined using the X-ray powder diffraction (XRPD) and batch equilibrium method. Increase in basal spacing (d) of montmorillonites saturated with 1.5 CEC of organic cation indicate that sorption of PTMA and HDTMA can exceed the saturation of 1 CEC. Both organic montmorillonites have shown higher uptake of the herbicide, compared to the inorganic montmorillonite. Comparing the values Freundlich coefficients in batch equilibrium method, (presented in the form of log Kf and 1/n), it can be seen that the sorption decreases in the series: 0.5CEC> 1CEC> 1.5CEC> NaM, for both organic montmorillonites.

Study of SEM induced current and voltage contrast modes to assess semiconductor reliability

NASA Technical Reports Server (NTRS)

Beall, J. R.

1976-01-01

The purpose of the scanning electron microscopy study was to review the failure history of existing integrated circuit technologies to identify predominant failure mechanisms, and to evaluate the feasibility of their detection using SEM application techniques. The study investigated the effects of E-beam irradiation damage and contamination deposition rates; developed the necessary methods for applying the techniques to the detection of latent defects and weaknesses in integrated circuits; and made recommendations for applying the techniques.

In situ SEM Observation of Column-like and Foam-like CNT Array Nanoindentation

DTIC Science & Technology

2011-03-02

frompyrolization of iron(II) phthalocyanine , producing vertically aligned CNTs with a nominal outer diameter of 50 nm.11,12 The array was indented using a 40 40 μm...www.acsami.org In situ SEM Observation of Column-like and Foam-like CNT Array Nanoindentation Matthew R. Maschmann,†,‡Qiuhong Zhang,†,§ Robert Wheeler...multiple length scales. Their behavior is expected to rely heavily on the properties of individual constituent CNTs , interactions and load distribution

Morphology and Structure of Amino-fatty Acid Intercalated Montmorillonite

NASA Astrophysics Data System (ADS)

Reyes, Larry; Sumera, Florentino

2015-04-01

amino fatty acid, but decreased with increasing surfactant loading. This suggested that the amino fatty acid may be tethered to the clay structure via ionic interaction and/or ion-dipole attraction. Significant changes in the clay morphology, particle size and surface charge were observed after organo-modification. Scanning electron microscopy (SEM) revealed that the organo-clays have a disordered and flaky morphology, while the unmodified MMT appeared to be dispersed spherical grains. The effective (Z) diameter of Na+-MMT was found to be ~520 nm, but increased up to ~937 nm upon intercalation of 12-ALA. The zeta potential (ξ) of the clay materials, on the other hand, ranged from -33 mV for undmodified MMT to -16 mv (200CEC-AMMT clay). The possible occupational hazards of working with nanoclays should also be explored. Presently, the MTT-dye reduction assay was performed to determine cell viability of mouse monocyte-macrophages (J774A.1) after direct exposure to the clays. The cytotoxicity of the clays exhibited a chemistry and dose dependent response, with unmodified Na+-MMT as the most cytotoxic while the organo-clays exhibited low toxicity. These results demonstrated the successful intercalation of the surfactant for the production of organophilic clay materials for a wide range of applications.

Improving contact layer patterning using SEM contour based etch model

NASA Astrophysics Data System (ADS)

Weisbuch, François; Lutich, Andrey; Schatz, Jirka; Hertzsch, Tino; Moll, Hans-Peter

2016-10-01

The patterning of the contact layer is modulated by strong etch effects that are highly dependent on the geometry of the contacts. Such litho-etch biases need to be corrected to ensure a good pattern fidelity. But aggressive designs contain complex shapes that can hardly be compensated with etch bias table and are difficult to characterize with standard CD metrology. In this work we propose to implement a model based etch compensation method able to deal with any contact configuration. With the help of SEM contours, it was possible to get reliable 2D measurements particularly helpful to calibrate the etch model. The selections of calibration structures was optimized in combination with model form to achieve an overall errRMS of 3nm allowing the implementation of the model in production.

Toll-like receptor-mediated responses of primary intestinal epithelial cells during the development of colitis.

PubMed

Singh, Joy Carmelina Indira; Cruickshank, Sheena Margaret; Newton, Darren James; Wakenshaw, Louise; Graham, Anne; Lan, Jinggang; Lodge, Jeremy Peter Alan; Felsburg, Peter John; Carding, Simon Richard

2005-03-01

The interleukin-2-deficient (IL-2(-/-)) mouse model of ulcerative colitis was used to test the hypothesis that colonic epithelial cells (CEC) directly respond to bacterial antigens and that alterations in Toll-like receptor (TLR)-mediated signaling may occur during the development of colitis. TLR expression and activation of TLR-mediated signaling pathways in primary CEC of healthy animals was compared with CEC in IL-2(-/-) mice during the development of colitis. In healthy animals, CEC expressed functional TLR, and in response to the TLR4 ligand LPS, proliferated and secreted the cytokines IL-6 and monocyte chemoattractant protein-1 (MCP-1). However, the TLR-responsiveness of CEC in IL-2(-/-) mice was different with decreased TLR4 responsiveness and augmented TLR2 responses that result in IL-6 and MCP-1 secretion. TLR signaling in CEC did not involve NF-kappaB (p65) activation with the inhibitory p50 form of NF-kappaB predominating in CEC in both the healthy and inflamed colon. Development of colitis was, however, associated with the activation of MAPK family members and upregulation of MyD88-independent signaling pathways characterized by increased caspase-1 activity and IL-18 production. These findings identify changes in TLR expression and signaling during the development of colitis that may contribute to changes in the host response to bacterial antigens seen in colitis.

Mapping the Complex Morphology of Cell Interactions with Nanowire Substrates Using FIB-SEM

PubMed Central

Jensen, Mikkel R. B.; Łopacińska, Joanna; Schmidt, Michael S.; Skolimowski, Maciej; Abeille, Fabien; Qvortrup, Klaus; Mølhave, Kristian

2013-01-01

Using high resolution focused ion beam scanning electron microscopy (FIB-SEM) we study the details of cell-nanostructure interactions using serial block face imaging. 3T3 Fibroblast cellular monolayers are cultured on flat glass as a control surface and on two types of nanostructured scaffold substrates made from silicon black (Nanograss) with low- and high nanowire density. After culturing for 72 hours the cells were fixed, heavy metal stained, embedded in resin, and processed with FIB-SEM block face imaging without removing the substrate. The sample preparation procedure, image acquisition and image post-processing were specifically optimised for cellular monolayers cultured on nanostructured substrates. Cells display a wide range of interactions with the nanostructures depending on the surface morphology, but also greatly varying from one cell to another on the same substrate, illustrating a wide phenotypic variability. Depending on the substrate and cell, we observe that cells could for instance: break the nanowires and engulf them, flatten the nanowires or simply reside on top of them. Given the complexity of interactions, we have categorised our observations and created an overview map. The results demonstrate that detailed nanoscale resolution images are required to begin understanding the wide variety of individual cells’ interactions with a structured substrate. The map will provide a framework for light microscopy studies of such interactions indicating what modes of interactions must be considered. PMID:23326412

Tensile experiments and SEM fractography on bovine subchondral bone.

PubMed

Braidotti, P; Bemporad, E; D'Alessio, T; Sciuto, S A; Stagni, L

2000-09-01

Subchondral bone undecalcified samples, extracted from bovine femoral heads, are subjected to a direct tensile load. The Young's modulus of each sample is determined from repeated tests within the elastic limit. In a last test, the tensile load is increased up to the specimen failure, determining the ultimate tensile strength. The investigation is performed on both dry and wet specimens. The measured Young's modulus for dry samples is 10.3+/-2.5GPa, while that of wet samples is 3.5+/-1.2GPa. The ultimate tensile strengths are 36+/-10 and 30+/-7.5MPa for dry and wet specimens, respectively. SEM micrographs of failure surfaces show characteristic lamellar bone structures, with lamellae composed of calcified collagen fibers. Rudimentary osteon-like structures are also observed. Failure surfaces of wet samples show a marked fiber pull-out, while delamination predominates in dry samples. The obtained results are interpreted on the basis of the deformation mechanisms typical of fiber-reinforced laminated composite materials.

SOFC Microstructures (PFIB-SEM and synthetic) from JPS 2018

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

Hsu, Tim; Epting, William K; Mahbub, Rubayyat

This is the microstructural data used in the publication "Mesoscale characterization of local property distributions in hetergeneous electrodes" by Tim Hsu, William K. Epting, Rubayyat Mahbub, et al., published in the Journal of Power Sources in 2018 (DOI 10.1016/j.jpowsour.2018.03.025). Included are a commercial cathode and anode active layer (Materials and Systems Research, Inc., Salt Lake City, UT) imaged by Xe plasma FIB-SEM (FEI, Hillsboro, OR), and four synthetic microstructures of varying particle size distribution widths generated by DREAM3D (BlueQuartz Software, Springboro, OH). For the MSRI electrodes, both the original greyscale and the segmented versions are provided. Each .zip file containsmore » a "stack" of .tif image files in the Z dimension, and an .info ascii text file containing useful information like voxel sizes and phase IDs. More details can be found in the pertinent publication at http://dx.doi.org/10.1016/j.jpowsour.2018.03.025.« less

FIB/SEM technology and high-throughput 3D reconstruction of dendritic spines and synapses in GFP-labeled adult-generated neurons.

PubMed

Bosch, Carles; Martínez, Albert; Masachs, Nuria; Teixeira, Cátia M; Fernaud, Isabel; Ulloa, Fausto; Pérez-Martínez, Esther; Lois, Carlos; Comella, Joan X; DeFelipe, Javier; Merchán-Pérez, Angel; Soriano, Eduardo

2015-01-01

The fine analysis of synaptic contacts is usually performed using transmission electron microscopy (TEM) and its combination with neuronal labeling techniques. However, the complex 3D architecture of neuronal samples calls for their reconstruction from serial sections. Here we show that focused ion beam/scanning electron microscopy (FIB/SEM) allows efficient, complete, and automatic 3D reconstruction of identified dendrites, including their spines and synapses, from GFP/DAB-labeled neurons, with a resolution comparable to that of TEM. We applied this technology to analyze the synaptogenesis of labeled adult-generated granule cells (GCs) in mice. 3D reconstruction of dendritic spines in GCs aged 3-4 and 8-9 weeks revealed two different stages of dendritic spine development and unexpected features of synapse formation, including vacant and branched dendritic spines and presynaptic terminals establishing synapses with up to 10 dendritic spines. Given the reliability, efficiency, and high resolution of FIB/SEM technology and the wide use of DAB in conventional EM, we consider FIB/SEM fundamental for the detailed characterization of identified synaptic contacts in neurons in a high-throughput manner.

Vulnerability of corneal endothelial cells to mechanical trauma from indentation forces assessed using contact mechanics and fluorescence microscopy.

PubMed

Ramirez-Garcia, Manuel A; Khalifa, Yousuf M; Buckley, Mark R

2018-06-05

Corneal endothelial cell (CEC) loss occurs from tissue manipulation during anterior segment surgery and corneal transplantation as well as from contact with synthetic materials like intraocular lenses and tube shunts. While several studies have quantified CEC loss for specific surgical steps, the vulnerability of CECs to isolated, controllable and measurable mechanical forces has not been assessed previously. The purpose of this study was to develop an experimental testing platform where the susceptibility of CECs to controlled mechanical trauma could be measured. The corneal endothelial surfaces of freshly dissected porcine corneas were subjected to a range of indentation forces via a spherical stainless steel bead. A cell viability assay in combination with high-resolution fluorescence microscopy was used to visualize and quantify injured/dead CEC densities before and after mechanical loading. In specimens subjected to an indentation force of 9 mN, the mean ± SD peak contact pressure P 0 was 18.64 ± 3.59 kPa (139.81 ± 26.93 mmHg) in the center of indentation and decreased radially outward. Injured/dead CEC densities were significantly greater (p ≤ 0.001) after mechanical indentation of 9 mN (167 ± 97 cells/mm 2 ) compared to before indentation (39 ± 52 cells/mm 2 ) and compared to the sham group (34 ± 31 cells/mm 2 ). In specimens subjected to "contact only" - defined as an applied indentation force of 0.65 mN - the peak contact pressure P 0 was 7.31 ± 1.5 kPa (54.83 ± 11.25 mmHg). In regions where the contact pressures was below 78% of P 0 (<5.7 kPa or 42.75 mmHg), injured/dead CEC densities were within the range of CEC loss observed in the sham group, suggesting negligible cell death. These findings indicate that CECs are highly susceptible to mechanical trauma via indentation, supporting the established "no-touch" policy for ophthalmological procedures. While CECs can potentially remain

Near-ground ozone source attributions and outflow in central eastern China during MTX2006

NASA Astrophysics Data System (ADS)

Li, J.; Wang, Z.; Akimoto, H.; Yamaji, K.; Takigawa, M.; Pochanart, P.; Liu, Y.; Tanimoto, H.; Kanaya, Y.

2008-12-01

A 3-D regional chemical transport model, the Nested Air Quality Prediction Model System (NAQPMS), with an on-line tracer tagging module was used to study the source of the near-ground (<1.5 km above ground level) ozone at Mt. Tai (36.25° N, 117.10° E, 1534 m a.s.l.) in Central Eastern China (CEC) during the Mount Tai eXperiment 2006 (MTX2006). The model reproduced the temporal and spatial variations of near-ground ozone and other pollutants, and it captured highly polluted and clean cases well. The simulated near-ground ozone level over CEC was 60-85 ppbv (parts per billion by volume), which was higher than values in Japan and over the North Pacific (20-50 ppbv). The simulated tagged tracer data indicated that the regional-scale transport of chemically produced ozone over other areas in CEC contributed to the greatest fraction (49%) of the near-ground mean ozone at Mt. Tai in June; in situ photochemistry contributed only 12%. Due to high anthropogenic and biomass burning emissions that occurred in the southern part of the CEC, the contribution to ground ozone levels from this area played the most important role (32.4 ppbv, 37.9% of total ozone) in the monthly mean ozone concentration at Mt. Tai; values reached 59 ppbv (62%) on 6-7 June 2006. The monthly mean horizontal distribution of chemically produced ozone from various ozone production regions indicated that photochemical reactions controlled the spatial distribution of O3 over CEC. The regional-scale transport of pollutants also played an important role in the spatial and temporal distribution of ozone over CEC. Chemically produced ozone from the southern part of the study region can be transported northeastwardly to the northern rim of CEC; the mean contribution was 5-10 ppbv, and it reached 25 ppbv during high ozone events. Studies of the outflow of CEC ozone and its precursors, as well as their influences and contributions to the ozone level over adjacent regions/countries, revealed that the contribution

Regional-scale modeling of near-ground ozone in the Central East China, source attributions and an assessment of outflow to East Asia The role of regional-scale transport during MTX2006

NASA Astrophysics Data System (ADS)

Li, J.; Wang, Z.; Akimoto, H.; Yamaji, K.; Takigawa, M.; Pochanart, P.; Liu, Y.; Kanaya, Y.

2008-07-01

A 3-D regional chemical transport model, the Nested Air Quality Prediction Model System (NAQPMS), with an on-line tracer tagging module was applied to study the source of the near-ground (<1.5 km above ground level) ozone at Mt. Tai (36.25°N, 117.10°E, 1534 m a.s.l.) in Central East China (CEC) during the Mount Tai eXperiment 2006 (MTX2006): regional ozone photochemistry and aerosol studies in Central East China in June, 2006. The model reproduced the temporal and spatial variations of near-ground ozone and other pollutants. In particular, the model captured highly polluted and clean cases well. The simulated near-ground ozone over CEC is 60 85 ppbv (parts per billion by volume), higher than those (20 50 ppbv) in Japan and over the North Pacific. The simulated tagged tracer indicates that the regional-scale transport of chemically produced ozone over other areas in CEC contributes to the most fractions (49%) of the near-ground mean ozone at Mt. Tai in June, rather than the in-situ photochemistry (12%). Due to high anthropogenic and biomass burning emissions, the contributions of the ground ozone from the southern part of CEC plays the most important role (32.4 ppbv, 37.9% of total ozone) in the monthly mean ozone concentration at Mt. Tai, which even reached 59 ppbv (62%) on 6 7 June 2006. The monthly mean horizontal distribution of chemically produced ozone from various source regions indicates that the spatial distribution of O3 over CEC is controlled by the photochemical reactions. In addition, the regional-scale transport of pollutants also plays an important role in the spatial and temporal distribution of ozone over CEC. The chemically produced ozone from the southern part of the study region can be transported northeastwardly to the northern rim of CEC. The mean contribution is 5 10 ppbv, and it can reach 25 ppbv during high ozone events. This work also studied the outflow of CEC ozone and its precursors, as well as their influences and contributions to the

Situational Effects May Account for Gain Scores in Cognitive Ability Testing: A Longitudinal SEM Approach

ERIC Educational Resources Information Center

Matton, Nadine; Vautier, Stephane; Raufaste, Eric

2009-01-01

Mean gain scores for cognitive ability tests between two sessions in a selection setting are now a robust finding, yet not fully understood. Many authors do not attribute such gain scores to an increase in the target abilities. Our approach consists of testing a longitudinal SEM model suitable to this view. We propose to model the scores' changes…

Subjective Values of Quality of Life Dimensions in Elderly People. A SEM Preference Model Approach

ERIC Educational Resources Information Center

Elosua, Paula

2011-01-01

This article proposes a Thurstonian model in the framework of Structural Equation Modelling (SEM) to assess preferences among quality of life dimensions for the elderly. Data were gathered by a paired comparison design in a sample comprised of 323 people aged from 65 to 94 years old. Five dimensions of quality of life were evaluated: Health,…

Modelling CEC variations versus structural iron reduction levels in dioctahedral smectites. Existing approaches, new data and model refinements.

PubMed

Hadi, Jebril; Tournassat, Christophe; Ignatiadis, Ioannis; Greneche, Jean Marc; Charlet, Laurent

2013-10-01

tetrahedral bearing nontronites (SWa-1, GAN and NAu-1) all exhibit the same behaviour at low reduction levels. Consequently, we restricted our model to the case of moderate reduction (<30%) in low tetrahedral Fe-bearing nontronites. Our adapted model provides the relative amounts of Na(+) (p) and H(+) (ni) cations incorporated in the structure as a function of the amount of Fe reduction. Two equations enable the investigated systems to be described: p=m/(1+Kr·ω·mrel) and ni=Kr·ω·m·mrel/(1+Kr·ω·mrel); where m is the Fe(II) content, mrel, the reduction level (m/mtot), ω, the cation exchange capacity (CEC, and Kr, an empirical constant specific to the system. Copyright © 2013 Elsevier Inc. All rights reserved.

Towards identifying the next generation of superfund and hazardous waste site contaminants

USGS Publications Warehouse

Ela, Wendell P.; Sedlak, David L.; Barlaz, Morton A.; Henry, Heather F.; Muir, Derek C.G.; Swackhamer, Deborah L.; Weber, Eric J.; Arnold, Robert G.; Ferguson, P. Lee; Field, Jennifer A.; Furlong, Edward T.; Giesy, John P.; Halden, Rolf U.; Henry, Tala; Hites, Ronald A.; Hornbuckle, Keri C.; Howard, Philip H.; Luthy, Richard G.; Meyer, Anita K.; Saez, A. Eduardo; vom Saal, Frederick S.; Vulpe, Chris D.; Wiesner, Mark R.

2011-01-01

Conclusions A need exists for a carefully considered and orchestrated expansion of programmatic and research efforts to identify, evaluate, and manage CECs of hazardous waste site relevance, including developing an evolving list of priority CECs, intensifying the identification and monitoring of likely sites of present or future accumulation of CECs, and implementing efforts that focus on a holistic approach to prevention.

A pilot study about the oncologic safety of colonic self-expandable metal stents (SEMS) in obstructive colon cancer: is occlusion always better than "silent" perforation?

PubMed

Zanghì, A; Piccolo, G; Cavallaro, A; Pulvirenti, E; Lo Menzo, E; Cardì, F; Di Vita, M; Cappellani, A

2016-12-01

To evaluate the oncologic safety of colonic self-expandable metal stents (SEMS) in obstructive colon cancer. We retrospectively reviewed all the patients who were treated with endoscopic placement of a self-expandable metallic stent (SEMS) at our institution. A total of 26 patients were identified during the study period, of which 24 patients (92.30%) were treated with SEMS as a bridge-to-surgery and 2 (7.69%) as palliation. In 22 cases (80.76%), the stenosis was localized to the left side. Clinical success with resolution of bowel obstructions was achieved in 22 (84.61%) patients within a short period of time. Among patients treated successfully with SEMS insertion as bridge to surgery (n = 22), 20 (90.9%) underwent one-stage surgery with primary anastomosis while 2 patients (9.09%) underwent colostomy due to intraoperative evidence of a covered perforation by cancer tissue in the pelvis. Patients with subclinical perforation developed an early peritoneal carcinomatosis, 10 patients treated with curative intent subsequently developed liver metastasis after 24 months. We reported an overall poor outcome among patients treated with the insertion of SEMS. This led us to think that, in some cases, occlusion may be better than a "silent" perforation.

A new method using Scanning Electron Microscopy (SEM) for preparation of anisopterous odonates.

PubMed

Del Palacio, Alejandro; Sarmiento, Patricia Laura; Javier, Muzón

2017-10-01

Anisopterous odonate male's secondary genitalia is a complex of several structures, among them the vesica spermalis is the most informative with important specific characters. The observation of those characters, mostly of membranous nature, is difficult in the Scanning Electron Microscope due to dehydration and metallization processes. In this contribution, we discuss a new and low cost procedure for the observation of these characters in the SEM, compatible with the most common agents used for preserving specimens. © 2017 Wiley Periodicals, Inc.

Variations in surface roughness of seven orthodontic archwires: an SEM-profilometry study

PubMed Central

Rakhshan, Vahid; Pousti, Maryam; Rahimi, Hajir; Shariati, Mahsa; Aghamohamadi, Bahareh

2012-01-01

Objective The purpose of this study was to evaluate the surface roughness (SR) of 2 types of orthodontic archwires made by 4 different manufacturers. Methods This in vitro experimental study was conducted on 35 specimens of 7 different orthodontic archwires, namely, 1 nickel-titanium (NiTi) archwire each from the manufacturers American Orthodontics, OrthoTechnology, All-Star Orthodontics, and Smart Technology, and 1 stainless steel (SS) archwire each from the manufacturers American Orthodontics, OrthoTechnology, and All-Star Orthodontics. After analyzing the composition of each wire by energy-dispersive X-ray analysis, the SR of each wire was determined by scanning electron microscopy (SEM) and surface profilometry. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (α < 0.05). Results The average SR of NiTi wires manufactured by Smart Technology, American Orthodontics, OrthoTechnology, and All-Star Orthodontics were 1,289 ± 915 A°, 1,378 ± 372 A°, 2,444 ± 369 A°, and 5,242 ± 2,832 A°, respectively. The average SR of SS wires manufactured by All-Star Orthodontics, OrthoTechnology, and American Orthodontics were 710 ± 210 A°, 1,831 ± 1,156 A°, and 4,018 ± 2,214 A°, respectively. Similar to the results of profilometry, the SEM images showed more defects and cracks on the SS wire made by American Orthodontics and the NiTi wire made by All-Star Orthodontics than others. Conclusions The NiTi wire manufactured by All-Star Orthodontics and the SS wire made by American Orthodontics were the roughest wires. PMID:23112943

New controlled environment vitrification system for preparing wet samples for cryo-SEM.

PubMed

Ge, H; Suszynski, W J; Davis, H T; Scriven, L E

2008-01-01

A new controlled environment vitrification system (CEVS) has been designed and constructed to facilitate examination by cryogenic scanning electron microscopy (Cryo-SEM) of initial suspension state and of microstructure development in latex, latex-composite and other coatings while they still contain solvent. The new system has a main chamber with provisions for coating as well as drying, and for well-controlled plunging into cryogen. An added subsidiary chamber holds samples for drying or annealing over minutes to days before they are returned to the main chamber and plunged from it. In the main chamber, samples are blade-coated on 5 x 7 mm pieces of silicon wafer and held at selected temperature and humidity for successively longer times, either there or after transfer along a rail into the subsidiary chamber. They are then placed in the sample holder mounted on the plunge rod, so as to permit adjustment of the sample's attitude when it plunges, at controlled speed, into liquid ethane at its freezing point, to a chosen depth, in order to solidify the sample without significant shear or freezing artifacts. The entries of plunging samples and related sample holders into liquid ethane were recorded with a high-speed, high-resolution Photron digital camera. The data were interpreted with a new hypothesis about the width of the band of extremely rapid cooling by deeply subcooled nucleate boiling below the line of entry. Complementary cryo-SEM images revealed that the freezing rate and surface shearing of a sample need to be balanced by adjusting the plunging attitude.

An investigation of adhesive/adherend and fiber/matrix interactions. Part B: SEM/ESCA analysis of fracture surfaces

NASA Technical Reports Server (NTRS)

Beck, B.; Widyani, E.; Wightman, J. P.

1983-01-01

Adhesion was studied with emphasis on the characterization of surface oxide layers, the analysis of fracture surfaces, and the interaction of matrices and fibers. A number of surface features of the fractured lap shear samples were noted in the SEM photomicrographs including the beta phase alloy of the Ti 6-4 adherend, the imprint of the adherend on the adhesive failure surface, increased void density for high temperature samples, and the alumina filler particles. Interfacial failure of some of the fractured lap shear samples is invariably characterized by the appearance of an ESCA oxygen photopeak at 530.3 eV assigned to the surface oxide layer of Ti 6-4 adherend. The effect of grit blasting on carbon fiber composites is evident in the SEM analysis. A high surface fluorine concentration on the composite surface is reduced some ten fold by grit blasting.

Microfluidic assay of circulating endothelial cells in coronary artery disease patients with angina pectoris

PubMed Central

Chen, Shuiyu; Sun, Yukun; Neoh, Kuang Hong; Chen, Anqi; Li, Weiju; Yang, Xiaorui

2017-01-01

Background Circulating endothelial cells (CECs) are widely reported as a promising biomarker of endothelial damage/dysfunction in coronary artery disease (CAD). The two popular methods of CEC quantification include the use of immunomagnetic beads separation (IB) and flow cytometry analysis (FC); however, they suffer from two main shortcomings that affect their diagnostic and prognostic responses: non-specific bindings of magnetic beads to non-target cells and a high degree of variability in rare cell identification, respectively. We designed a microfluidic chip with spatially staggered micropillars for the efficient harvesting of CECs with intact cellular morphology in an attempt to revisit the diagnostic goal of CEC counts in CAD patients with angina pectoris. Methods A label-free microfluidic assay that involved an in-situ enumeration and immunofluorescent identification (DAPI+/CD146+/VEGFR1+/CD45-) of CECs was carried out to assess the CEC count in human peripheral blood samples. A total of 55 CAD patients with angina pectoris [16 with chronic stable angina (CSA) and 39 with unstable angina (UA)], together with 15 heathy controls (HCs) were enrolled in the study. Results CEC counts are significantly higher in both CSA and UA groups compared to the HC group [respective medians of 6.9, 10.0 and 1.5 cells/ml (p < 0.01)]. Further, a significant elevation of CEC count was observed in the three UA subgroups [low risk (5.3) vs. intermediate risk (10.8) vs. high risk (18.0) cells/ml, p < 0.001) classified in accordance to the TIMI NSTEMI/UA risk score system. From the receiver-operating characteristic curve analysis, the AUCs for distinguishing CSA and UA from HC were 0.867 and 0.938, respectively. The corresponding sensitivities were 87.5% and 84.6% and the specificities were 66.7% and 86.7%, respectively. Conclusions Our microfluidic assay system is efficient and stable for CEC capture and enumeration. The results showed that the CEC count has the potential to be a

Contaminants of emerging concern in tributaries to the Laurentian Great Lakes: II. Biological consequences of exposure

PubMed Central

Brigham, Mark E.; Choy, Steven J.; Moore, Jeremy N.; Banda, Jo A.; Gefell, Daniel J.; Minarik, Thomas A.

2017-01-01

The Laurentian Great Lakes contain one fifth of the world’s surface freshwater and have been impacted by human activity since the Industrial Revolution. In addition to legacy contaminants, nitrification and invasive species, this aquatic ecosystem is also the recipient of Contaminants of Emerging Concern (CECs) with poorly understood biological consequences. In the current study, we documented the presence, concentrations, and biological effects of CECs across 27 field sites in six Great Lakes tributaries by examining over 2250 resident and caged sunfish (Lepomis ssp.) for a variety of morphological and physiological endpoints and related these results to CEC occurrence. CEC were ubiquitous across studies sites and their presence and concentrations in water and sediment were highest in effluent dominated rivers and downstream of municipal wastewater treatment plant discharges. However, even putative upstream reference sites were not free of CEC presence and fish at these sites exhibited biological effects consistent with CEC exposure. Only the Fox River exhibited consistent adverse biological effects, including increased relative liver size, greater prominence of hepatocyte vacuoles and increased plasma glucose concentrations. Canonical Redundancy Analysis revealed consistent patterns of biological consequences of CEC exposure across all six tributaries. Increasing plasma glucose concentrations, likely as a result of pollutant-induced metabolic stress, were associated with increased relative liver size and greater prominence of hepatocyte vacuoles. These indicators of pollutant exposure were inversely correlated with indicators of reproductive potential including smaller gonad size and less mature gametes. The current study highlights the need for greater integration of chemical and biological studies and suggests that CECs in the Laurentian Great Lakes Basin may adversely affect the reproductive potential of exposed fish populations. PMID:28953953

Contaminants of emerging concern in tributaries to the Laurentian Great Lakes: II. Biological consequences of exposure.

PubMed

Thomas, Linnea M; Jorgenson, Zachary G; Brigham, Mark E; Choy, Steven J; Moore, Jeremy N; Banda, Jo A; Gefell, Daniel J; Minarik, Thomas A; Schoenfuss, Heiko L

2017-01-01

The Laurentian Great Lakes contain one fifth of the world's surface freshwater and have been impacted by human activity since the Industrial Revolution. In addition to legacy contaminants, nitrification and invasive species, this aquatic ecosystem is also the recipient of Contaminants of Emerging Concern (CECs) with poorly understood biological consequences. In the current study, we documented the presence, concentrations, and biological effects of CECs across 27 field sites in six Great Lakes tributaries by examining over 2250 resident and caged sunfish (Lepomis ssp.) for a variety of morphological and physiological endpoints and related these results to CEC occurrence. CEC were ubiquitous across studies sites and their presence and concentrations in water and sediment were highest in effluent dominated rivers and downstream of municipal wastewater treatment plant discharges. However, even putative upstream reference sites were not free of CEC presence and fish at these sites exhibited biological effects consistent with CEC exposure. Only the Fox River exhibited consistent adverse biological effects, including increased relative liver size, greater prominence of hepatocyte vacuoles and increased plasma glucose concentrations. Canonical Redundancy Analysis revealed consistent patterns of biological consequences of CEC exposure across all six tributaries. Increasing plasma glucose concentrations, likely as a result of pollutant-induced metabolic stress, were associated with increased relative liver size and greater prominence of hepatocyte vacuoles. These indicators of pollutant exposure were inversely correlated with indicators of reproductive potential including smaller gonad size and less mature gametes. The current study highlights the need for greater integration of chemical and biological studies and suggests that CECs in the Laurentian Great Lakes Basin may adversely affect the reproductive potential of exposed fish populations.

Contaminants of emerging concern in tributaries to the Laurentian Great Lakes: II. Biological consequences of exposure

USGS Publications Warehouse

Thomas, Linnea M.; Jorgenson, Zachary G.; Brigham, Mark E.; Choy, Steven J.; Moore, Jeremy N.; Banda, Jo A.; Gefell, D.J.; Minarik, Thomas A.; Schoenfuss, Heiko L.

2017-01-01

The Laurentian Great Lakes contain one fifth of the world’s surface freshwater and have been impacted by human activity since the Industrial Revolution. In addition to legacy contaminants, nitrification and invasive species, this aquatic ecosystem is also the recipient of Contaminants of Emerging Concern (CECs) with poorly understood biological consequences. In the current study, we documented the presence, concentrations, and biological effects of CECs across 27 field sites in six Great Lakes tributaries by examining over 2250 resident and caged sunfish (Lepomis ssp.) for a variety of morphological and physiological endpoints and related these results to CEC occurrence. CEC were ubiquitous across studies sites and their presence and concentrations in water and sediment were highest in effluent dominated rivers and downstream of municipal wastewater treatment plant discharges. However, even putative upstream reference sites were not free of CEC presence and fish at these sites exhibited biological effects consistent with CEC exposure. Only the Fox River exhibited consistent adverse biological effects, including increased relative liver size, greater prominence of hepatocyte vacuoles and increased plasma glucose concentrations. Canonical Redundancy Analysis revealed consistent patterns of biological consequences of CEC exposure across all six tributaries. Increasing plasma glucose concentrations, likely as a result of pollutant-induced metabolic stress, were associated with increased relative liver size and greater prominence of hepatocyte vacuoles. These indicators of pollutant exposure were inversely correlated with indicators of reproductive potential including smaller gonad size and less mature gametes. The current study highlights the need for greater integration of chemical and biological studies and suggests that CECs in the Laurentian Great Lakes Basin may adversely affect the reproductive potential of exposed fish populations.

Supporting Current Energy Conversion Projects through Numerical Modeling

NASA Astrophysics Data System (ADS)

James, S. C.; Roberts, J.

2016-02-01

The primary goals of current energy conversion (CEC) technology being developed today are to optimize energy output and minimize environmental impact. CEC turbines generate energy from tidal and current systems and create wakes that interact with turbines located downstream of a device. The placement of devices can greatly influence power generation and structural reliability. CECs can also alter the environment surrounding the turbines, such as flow regimes, sediment dynamics, and water quality. These alterations pose potential stressors to numerous environmental receptors. Software is needed to investigate specific CEC sites to simulate power generation and hydrodynamic responses of a flow through a CEC turbine array so that these potential impacts can be evaluated. Moreover, this software can be used to optimize array layouts that yield the least changes to the environmental (i.e., hydrodynamics, sediment dynamics, and water quality). Through model calibration exercises, simulated wake profiles and turbulence intensities compare favorably to the experimental data and demonstrate the utility and accuracy of a fast-running tool for future siting and analysis of CEC arrays in complex domains. The Delft3D modeling tool facilitates siting of CEC projects through optimization of array layouts and evaluation of potential environmental effect all while provide a common "language" for academics, industry, and regulators to be able to discuss the implications of marine renewable energy projects. Given the enormity of any full-scale marine renewable energy project, it necessarily falls to modeling to evaluate how array operations must be addressed in an environmental impact statement in a way that engenders confidence in the assessment of the CEC array to minimize environmental effects.

Circulating Endothelial Cells and Endothelial Function predict Major Adverse Cardiac Events and Early Adverse Left Ventricular Remodeling in Patients with ST-Segment Elevation Myocardial Infarction

PubMed Central

Magdy, Abdel Hamid; Bakhoum, Sameh; Sharaf, Yasser; Sabry, Dina; El-Gengehe, Ahmed T; Abdel-Latif, Ahmed

2016-01-01

Endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) are mobilized from the bone marrow and increase in the early phase after ST-elevation myocardial infarction (STEMI). The aim of this study was to assess the prognostic significance of CECs and indices of endothelial dysfunction in patients with STEMI. In 78 patients with acute STEMI, characterization of CD34+/VEGFR2+ CECs, and indices of endothelial damage/dysfunction such as brachial artery flow mediated dilatation (FMD) were determined. Blood samples for CECs assessment and quantification were obtained within 24 hours of admission and FMD was assessed during the index hospitalization. At 30 days follow up, the primary composite end point of major cardiac adverse events (MACE) consisting of all-cause mortality, recurrent non-fatal MI, or heart failure and the secondary endpoint of early adverse left ventricular (LV) remodeling were analyzed. The 17 patients (22%) who developed MACE had significantly higher CEC level (P = 0.004), vWF level (P =0.028), and significantly lower FMD (P = 0.006) compared to the remaining patients. Logistic regression analysis showed that CECs level and LV ejection fraction were independent predictors of MACE. The areas under the receiver operating characteristic curves (ROC) for CEC level, FMD, and the logistic model with both markers were 0.73, 0.75, and 0.82 respectively for prediction of the MACE. The 16 patients who developed the secondary endpoint had significantly higher CEC level compared to remaining patients (p =0.038). In conclusion, increased circulating endothelial cells and endothelial dysfunction predicted the occurrence of major adverse cardiac events and adverse cardiac remodeling in patients with STEMI. PMID:26864952

Influence of montmorillonites exchange capacity on the basal spacing of cation–anion organo-montmorillonites

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

Sanqin, Wu; Zepeng, Zhang, E-mail: unite508@163.com; Yunhua, Wang

Graphical abstract: This picture shows the distribution of organic modifier (CTAB and SDS) in Mt interlayer and the basal spacing changes of Mt modified by CTAB and SDS. Organic modifier molecule in Mt interlayer is more and more orderly. The basal spacing of Mt is from 1.5 nm to 5 nm as modifier added. - Highlights: • The d{sub 001} of Ca-Mt, R-Na-Mt, Na-Mt modified by CTAB and SDS can reach 5 nm. • It is easier to get cation–anion OMt with greater d{sub 001} if CEC is lower. • The organic molecules distribution in cation–anion OMt was analyzed. •more » The influence mechanism of Ca-Mt CEC on the d{sub 001} was discussed. - Abstract: With cationic and anionic surfactants cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfonate (SDS) as modifiers, Ca-montmorillonites (Ca-Mt), artificial Na-montmorillonites (R-Na-Mt) and natural Na-montmorillonites (Na-Mt) with different cation exchange capacity (CEC) were modified by solution intercalation method, respectively. Then cation–anion organo-montmorillonites (OMt) were prepared. The influence of CEC on the basal spacing of cation–anion OMt and the influence mechanism were discussed by X-ray diffraction (XRD) and zeta potential testing. The results indicate that the basal spacing of cation–anion OMt is related to CEC. For the same type montmorillonites, the basal spacing of cation–anion OMt decreases with the increase of CEC and it is easier to get cation–anion OMt with greater basal spacing when CEC is lower. Moreover, the CEC of Na-Mt has the greatest influence on the basal spacing of cation–anion OMt.« less

Isolation of a circulating CD45−, CD34dim cell population and validation of their endothelial phenotype

PubMed Central

Tropea, Margaret M.; Harper, Bonnie J. A.; Graninger, Grace M.; Phillips, Terry M.; Ferreyra, Gabriela; Mostowski, Howard S.; Danner, Robert L.; Suffredini, Anthony F.; Solomon, Michael A.

2016-01-01

Summary Accurately detecting circulating endothelial cells (CECs) is important since their enumeration has been proposed as a biomarker to measure injury to the vascular endothelium. However, there is no single methodology for determining CECs in blood, making comparison across studies difficult. Many methods for detecting CECs rely on characteristic cell surface markers and cell viability indicators, but lack secondary validation. Here, a CEC population in healthy adult human subjects was identified by flow cytometry as CD45−, CD34dim that is comparable to a previously described CD45−, CD31bright population. In addition, nuclear staining with 7-aminoactinomycin D (7-AAD) was employed as a standard technique to exclude dead cells. Unexpectedly, the CD45−, CD34dim, 7-AAD− CECs lacked surface detectable CD146, a commonly used marker of CECs. Furthermore, light microscopy revealed this cell population to be composed primarily of large cells without a clearly defined nucleus. Nevertheless, immunostains still demonstrated the presence of the lectin Ulex europaeus and van Willebrand factor. Ultramicro analytical immunochemistry assays for the endothelial cell proteins CD31, CD34, CD62E, CD105, CD141, CD144 and vWF indicated these cells possess an endothelial phenotype. However, only a small amount of RNA, which was mostly degraded, could be isolated from these cells. Thus the majority of CECs in healthy individuals as defined by CD45−, CD34dim, and 7-AAD− have shed their CD146 surface marker and are senescent cells without an identifiable nucleus and lacking RNA of sufficient quantity and quality for transcriptomal analysis. This study highlights the importance of secondary validation of CEC identification. PMID:25057108

Circulating endothelial cells are increased in chronic myeloid leukemia blast crisis.

PubMed

Godoy, C R T; Levy, D; Giampaoli, V; Chamone, D A F; Bydlowski, S P; Pereira, J

2015-06-01

We measured circulating endothelial precursor cells (EPCs), activated circulating endothelial cells (aCECs), and mature circulating endothelial cells (mCECs) using four-color multiparametric flow cytometry in the peripheral blood of 84 chronic myeloid leukemia (CML) patients and 65 healthy controls; and vascular endothelial growth factor (VEGF) by quantitative real-time PCR in 50 CML patients and 32 healthy controls. Because of an increase in mCECs, the median percentage of CECs in CML blast crisis (0.0146%) was significantly higher than in healthy subjects (0.0059%, P<0.01) and in the accelerated phase (0.0059%, P=0.01). There were no significant differences in the percentages of CECs in chronic- or active-phase patients and healthy subjects (P>0.05). In addition, VEGF gene expression was significantly higher in all phases of CML: 0.245 in blast crisis, 0.320 in the active phase, and 0.330 in chronic phase patients than it was in healthy subjects (0.145). In conclusion, CML in blast crisis had increased levels of CECs and VEGF gene expression, which may serve as markers of disease progression and may become targets for the management of CML.

Circulating Endothelial Cells and Endothelial Progenitor Cells in Pediatric Sepsis.

PubMed

Zahran, Asmaa Mohamad; Elsayh, Khalid Ibrahim; Mohamad, Ismail Lotfy; Hassan, Gamal Mohamad; Abdou, Madleen Adel A

2016-03-01

The aim of the study was to measure the number of circulating endothelial cells (CECs) and circulating endothelial progenitor cells (CEPs) in pediatric patients with sepsis and correlating it with the severity of the disease and its outcome. The study included 19 children with sepsis, 26 with complicated sepsis, and 30 healthy controls. The patients were investigated within 48 hours of pediatric intensive care unit admission together with flow cytometric detection of CECs and CEPs. The levels of both CECs and CEPs were significantly higher in patient with sepsis and complicated sepsis than the controls. The levels of CECs were higher in patients with complicated sepsis, whereas the levels of CEPs were lower in patients with complicated sepsis. Comparing the survival and nonsurvival septic patients, the levels of CEPs were significantly higher in the survival than in nonsurvival patients, whereas the levels of CECs were significantly lower in the survival than in nonsurvival patients. Serum albumin was higher in survival than in nonsurvival patients. Estimation of CECs and CEPs and their correlation with other parameters such as serum albumen could add important information regarding prognosis in septic pediatric patients.

A new challenge: in-situ investigation of the elusive nanostructures in wet halite and clay using BIB/FIB-cryo-SEM methods

NASA Astrophysics Data System (ADS)

Desbois, G.; Urai, J. L.

2009-04-01

Mudrocks and saltrocks form seals for hydrocarbon accumulations, aquitards and chemical barriers. The sealing capacity is controlled either by the rock microstructure or by chemical interactions between minerals and the permeating fluid. A detailed knowledge about the sealing characteristics is of particular interest in Petroleum Sciences. Other fields of interest are the storage of anthropogenic carbon dioxide and radioactive waste in geologic formations. A key factor to the understanding of sealing by mudstones and saltrocks is the study of their porosity. However, Halite and clay are so fluids sensitive that investigation on dried samples required by traditional methods of investigations (metal injection methods [6],[3]; magnetic susceptibility measurement [4]; SEM imaging of broken surfaces [5] and CT scanner computing [7]) are critical for robust interpretation. In one hand, none of these methods is able to directly describe the in-situ porosity at the pore scale and on the other hand, most of these methods require dried samples in which the natural structure of pores could be damaged due to the desiccation, dehydration and dissolution-recrystallisation of the fabric. SEM imaging is certainly the most direct approach to investigate the porosity but it is generally limited by the poor quality of the mechanically prepared surfaces. This problem is solved by the recent development of ion milling tools (FIB: Focussed Ion Beam or BIB: Broad Ion Beam, which allows producing in-situ high quality polished cross-sections suitable for high resolution pores SEM imaging at nano-scale. More over, new and innovative developments of the cryo-SEM approach in the Geosciences allow investigating samples under wet natural conditions. Thus, we are developing the combination of FIB/BIB-cryo-SEM methods ([1],[2]), which combine in one machine the vitrification of the pore fluids by very rapid cooling, the excavation of the sample by ion milling tool and SEM imaging. By these, we

Biomolecular hybrid material and process for preparing same and uses for same

DOEpatents

Kim, Jungbae [Richland, WA

2010-11-23

Disclosed is a composition and method for fabricating novel hybrid materials comprised of, e.g., carbon nanotubes (CNTs) and crosslinked enzyme clusters (CECs). In one method, enzyme-CNT hybrids are prepared by precipitation of enzymes which are subsequently crosslinked, yielding crosslinked enzyme clusters (CECs) on the surface of the CNTs. The CEC-enzyme-CNT hybrids exhibit high activity per unit area or mass as well as improved enzyme stability and longevity over hybrid materials known in the art. The CECs in the disclosed materials permit multilayer biocatalytic coatings to be applied to surfaces providing hybrid materials suitable for use in, e.g., biocatalytic applications and devices as described herein.

The innovation of cryo-SEM freeze-fracturing methodology demonstrated on high pressure frozen biofilm.

PubMed

Hrubanova, Kamila; Nebesarova, Jana; Ruzicka, Filip; Krzyzanek, Vladislav

2018-07-01

In this study we present an innovative method for the preparation of fully hydrated samples of microbial biofilms of cultures Staphylococcus epidermidis, Candida parapsilosis and Candida albicans. Cryo-scanning electron microscopy (cryo-SEM) and high-pressure freezing (HPF) rank among cutting edge techniques in the electron microscopy of hydrated samples such as biofilms. However, the combination of these techniques is not always easily applicable. Therefore, we present a method of combining high-pressure freezing using EM PACT2 (Leica Microsystems), which fixes hydrated samples on small sapphire discs, with a high resolution SEM equipped with the widely used cryo-preparation system ALTO 2500 (Gatan). Using a holder developed in house, a freeze-fracturing technique was applied to image and investigate microbial cultures cultivated on the sapphire discs. In our experiments, we focused on the ultrastructure of the extracellular matrix produced during cultivation and the relationships among microbial cells in the biofilm. The main goal of our investigations was the detailed visualization of areas of the biofilm where the microbial cells adhere to the substrate/surface. We show the feasibility of this technique, which is clearly demonstrated in experiments with various freeze-etching times. Copyright © 2018 Elsevier Ltd. All rights reserved.

30 CFR 250.1917 - What criteria for pre-startup review must be in my SEMS program?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 2 2012-07-01 2012-07-01 false What criteria for pre-startup review must be in... SHELF Safety and Environmental Management Systems (SEMS) § 250.1917 What criteria for pre-startup review...-startup safety and environmental review for new and significantly modified facilities that are subject to...

30 CFR 250.1917 - What criteria for pre-startup review must be in my SEMS program?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 2 2014-07-01 2014-07-01 false What criteria for pre-startup review must be in... SHELF Safety and Environmental Management Systems (SEMS) § 250.1917 What criteria for pre-startup review...-startup safety and environmental review for new and significantly modified facilities that are subject to...

30 CFR 250.1917 - What criteria for pre-startup review must be in my SEMS program?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 2 2013-07-01 2013-07-01 false What criteria for pre-startup review must be in... SHELF Safety and Environmental Management Systems (SEMS) § 250.1917 What criteria for pre-startup review...-startup safety and environmental review for new and significantly modified facilities that are subject to...

A combination of a SEM technique and X-ray microanalysis for studying the spore germination process of Clostridium tyrobutyricum.

PubMed

Bassi, Daniela; Cappa, Fabrizio; Cocconcelli, Pier Sandro

2009-06-01

Clostridium tyrobutyricum is an anaerobic bacterium responsible for late blowing defects during cheese ripening and it is of scientific interest for biological hydrogen production. A scanning electron microscopy (SEM) coating technique and X-ray microanalysis were developed to analyze the architecture and chemical composition of spores upon germination in response to environmental changes. In addition, we investigated the effects of different compounds on this process. Agents and environmental conditions inducing germination were characterized monitoring changes in optical density (OD). Among all tested conditions, the greatest drop in OD(625) (57.4%) was obtained when spores were incubated in l-alanine/l-lactate buffer, pH 4.6. In addition, a carbon-coating SEM technique and X-ray microanalysis were used to observe the architecture of spores and to examine calcium dipicolinate release. Conditions inducing C. tyrobutyricum spore germination were identified and SEM X-ray microanalysis clearly distinguished germinating from dormant spores. We confirmed that calcium dipicolinate release is one of the first events occurring. These microscopy methods could be considered sensitive tools for evaluating morphological and chemical changes in spores of C. tyrobutyricum during the initial phase of germination. Information gathered from this work may provide new data for further research on germination.

Healing of broken multiwalled carbon nanotubes using very low energy electrons in SEM: a route toward complete recovery.

PubMed

Kulshrestha, Neha; Misra, Abhishek; Hazra, Kiran Shankar; Roy, Soumyendu; Bajpai, Reeti; Mohapatra, Dipti Ranjan; Misra, D S

2011-03-22

We report the healing of electrically broken multiwalled carbon nanotubes (MWNTs) using very low energy electrons (3-10 keV) in scanning electron microscopy (SEM). Current-induced breakdown caused by Joule heating has been achieved by applying suitably high voltages. The broken tubes were examined and exposed to electrons of 3-10 keV in situ in SEM with careful maneuvering of the electron beam at the broken site, which results in the mechanical joining of the tube. Electrical recovery of the same tube has been confirmed by performing the current-voltage measurements after joining. This easy approach is directly applicable for the repairing of carbon nanotubes incorporated in ready devices, such as in on-chip horizontal interconnects or on-tip probing applications, such as in scanning tunneling microscopy.

Toward Identifying the Next Generation of Superfund and Hazardous Waste Site Contaminants

PubMed Central

Ela, Wendell P.; Sedlak, David L.; Barlaz, Morton A.; Henry, Heather F.; Muir, Derek C.G.; Swackhamer, Deborah L.; Weber, Eric J.; Arnold, Robert G.; Ferguson, P. Lee; Field, Jennifer A.; Furlong, Edward T.; Giesy, John P.; Halden, Rolf U.; Henry, Tala; Hites, Ronald A.; Hornbuckle, Keri C.; Howard, Philip H.; Luthy, Richard G.; Meyer, Anita K.; Sáez, A. Eduardo; vom Saal, Frederick S.; Vulpe, Chris D.; Wiesner, Mark R.

2011-01-01

Background This commentary evolved from a workshop sponsored by the National Institute of Environmental Health Sciences titled “Superfund Contaminants: The Next Generation” held in Tucson, Arizona, in August 2009. All the authors were workshop participants. Objectives Our aim was to initiate a dynamic, adaptable process for identifying contaminants of emerging concern (CECs) that are likely to be found in future hazardous waste sites, and to identify the gaps in primary research that cause uncertainty in determining future hazardous waste site contaminants. Discussion Superfund-relevant CECs can be characterized by specific attributes: They are persistent, bioaccumulative, toxic, occur in large quantities, and have localized accumulation with a likelihood of exposure. Although still under development and incompletely applied, methods to quantify these attributes can assist in winnowing down the list of candidates from the universe of potential CECs. Unfortunately, significant research gaps exist in detection and quantification, environmental fate and transport, health and risk assessment, and site exploration and remediation for CECs. Addressing these gaps is prerequisite to a preventive approach to generating and managing hazardous waste sites. Conclusions A need exists for a carefully considered and orchestrated expansion of programmatic and research efforts to identify, evaluate, and manage CECs of hazardous waste site relevance, including developing an evolving list of priority CECs, intensifying the identification and monitoring of likely sites of present or future accumulation of CECs, and implementing efforts that focus on a holistic approach to prevention. PMID:21205582

Toward identifying the next generation of superfund and hazardous waste site contaminants.

PubMed

Ela, Wendell P; Sedlak, David L; Barlaz, Morton A; Henry, Heather F; Muir, Derek C G; Swackhamer, Deborah L; Weber, Eric J; Arnold, Robert G; Ferguson, P Lee; Field, Jennifer A; Furlong, Edward T; Giesy, John P; Halden, Rolf U; Henry, Tala; Hites, Ronald A; Hornbuckle, Keri C; Howard, Philip H; Luthy, Richard G; Meyer, Anita K; Sáez, A Eduardo; Vom Saal, Frederick S; Vulpe, Chris D; Wiesner, Mark R

2011-01-01

This commentary evolved from a workshop sponsored by the National Institute of Environmental Health Sciences titled "Superfund Contaminants: The Next Generation" held in Tucson, Arizona, in August 2009. All the authors were workshop participants. Our aim was to initiate a dynamic, adaptable process for identifying contaminants of emerging concern (CECs) that are likely to be found in future hazardous waste sites, and to identify the gaps in primary research that cause uncertainty in determining future hazardous waste site contaminants. Superfund-relevant CECs can be characterized by specific attributes: They are persistent, bioaccumulative, toxic, occur in large quantities, and have localized accumulation with a likelihood of exposure. Although still under development and incompletely applied, methods to quantify these attributes can assist in winnowing down the list of candidates from the universe of potential CECs. Unfortunately, significant research gaps exist in detection and quantification, environmental fate and transport, health and risk assessment, and site exploration and remediation for CECs. Addressing these gaps is prerequisite to a preventive approach to generating and managing hazardous waste sites. A need exists for a carefully considered and orchestrated expansion of programmatic and research efforts to identify, evaluate, and manage CECs of hazardous waste site relevance, including developing an evolving list of priority CECs, intensifying the identification and monitoring of likely sites of present or future accumulation of CECs, and implementing efforts that focus on a holistic approach to prevention.

Plasma cholesterol homeostasis, HDL remodeling and function during the acute phase reaction.

PubMed

Zimetti, Francesca; De Vuono, Stefano; Gomaraschi, Monica; Adorni, Maria Pia; Favari, Elda; Ronda, Nicoletta; Ricci, Maria Anastasia; Veglia, Fabrizio; Calabresi, Laura; Lupattelli, Graziana

2017-10-01

Acute phase reaction (APR) is a systemic inflammation triggered by several conditions associated with lipid profile alterations. We evaluated whether APR also associates with changes in cholesterol synthesis and absorption, HDL structure, composition, and cholesterol efflux capacity (CEC). We analyzed 59 subjects with APR related to infections, oncologic causes, or autoimmune diseases and 39 controls. We detected no difference in markers of cholesterol synthesis and absorption. Conversely, a significant reduction of LpA-I- and LpAI:AII-containing HDL (-28% and -44.8%, respectively) and of medium-sized HDL (-10.5%) occurred in APR. Total HDL CEC was impaired in APR subjects (-18%). Evaluating specific CEC pathways, we found significant reductions in CEC by aqueous diffusion and by the transporters scavenger receptor B-I and ABCG1 (-25.5, -41.1 and -30.4%, respectively). ABCA1-mediated CEC was not affected. Analyses adjusted for age and gender provided similar results. In addition, correcting for HDL-cholesterol (HDL-C) levels, the differences in aqueous diffusion total and ABCG1-CEC remained significant. APR subjects displayed higher levels of HDL serum amyloid A (+20-folds; P = 0.003). In conclusion, APR does not associate with cholesterol synthesis and absorption changes but with alterations of HDL composition and a marked impairment of HDL CEC, partly independent of HDL-C serum level reduction. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

SEM with Missing Data and Unknown Population Distributions Using Two-Stage ML: Theory and Its Application

ERIC Educational Resources Information Center

Yuan, Ke-Hai; Lu, Laura

2008-01-01

This article provides the theory and application of the 2-stage maximum likelihood (ML) procedure for structural equation modeling (SEM) with missing data. The validity of this procedure does not require the assumption of a normally distributed population. When the population is normally distributed and all missing data are missing at random…

A two-step FEM-SEM approach for wave propagation analysis in cable structures

NASA Astrophysics Data System (ADS)

Zhang, Songhan; Shen, Ruili; Wang, Tao; De Roeck, Guido; Lombaert, Geert

2018-02-01

Vibration-based methods are among the most widely studied in structural health monitoring (SHM). It is well known, however, that the low-order modes, characterizing the global dynamic behaviour of structures, are relatively insensitive to local damage. Such local damage may be easier to detect by methods based on wave propagation which involve local high frequency behaviour. The present work considers the numerical analysis of wave propagation in cables. A two-step approach is proposed which allows taking into account the cable sag and the distribution of the axial forces in the wave propagation analysis. In the first step, the static deformation and internal forces are obtained by the finite element method (FEM), taking into account geometric nonlinear effects. In the second step, the results from the static analysis are used to define the initial state of the dynamic analysis which is performed by means of the spectral element method (SEM). The use of the SEM in the second step of the analysis allows for a significant reduction in computational costs as compared to a FE analysis. This methodology is first verified by means of a full FE analysis for a single stretched cable. Next, simulations are made to study the effects of damage in a single stretched cable and a cable-supported truss. The results of the simulations show how damage significantly affects the high frequency response, confirming the potential of wave propagation based methods for SHM.

FIB/SEM technology and high-throughput 3D reconstruction of dendritic spines and synapses in GFP-labeled adult-generated neurons

PubMed Central

Bosch, Carles; Martínez, Albert; Masachs, Nuria; Teixeira, Cátia M.; Fernaud, Isabel; Ulloa, Fausto; Pérez-Martínez, Esther; Lois, Carlos; Comella, Joan X.; DeFelipe, Javier; Merchán-Pérez, Angel; Soriano, Eduardo

2015-01-01

The fine analysis of synaptic contacts is usually performed using transmission electron microscopy (TEM) and its combination with neuronal labeling techniques. However, the complex 3D architecture of neuronal samples calls for their reconstruction from serial sections. Here we show that focused ion beam/scanning electron microscopy (FIB/SEM) allows efficient, complete, and automatic 3D reconstruction of identified dendrites, including their spines and synapses, from GFP/DAB-labeled neurons, with a resolution comparable to that of TEM. We applied this technology to analyze the synaptogenesis of labeled adult-generated granule cells (GCs) in mice. 3D reconstruction of dendritic spines in GCs aged 3–4 and 8–9 weeks revealed two different stages of dendritic spine development and unexpected features of synapse formation, including vacant and branched dendritic spines and presynaptic terminals establishing synapses with up to 10 dendritic spines. Given the reliability, efficiency, and high resolution of FIB/SEM technology and the wide use of DAB in conventional EM, we consider FIB/SEM fundamental for the detailed characterization of identified synaptic contacts in neurons in a high-throughput manner. PMID:26052271

PRIMUS/NAVCARE Cost-Effectiveness Analysis

DTIC Science & Technology

1991-04-08

ICD-9-CM diagnosis codes that occurred most frequently in the medical record sample - 328.9 ( otitis media , unspecified) and 465.9 (upper...when attention is focused upon a single diagnosis, the MTF CECs are no longer consistently above the PRIMUS CECs. For otitis media , the MTF CECs are...CHAMPUS-EQUIVALENT COSTS FOR SELECTED DIAGNOSES 328.9 OTITIS MEDIA , UNSPECIFIED Sample Size Mean 95% Confidence Interval Upper Limit Lower

Optimized multiparametric flow cytometric analysis of circulating endothelial cells and their subpopulations in peripheral blood of patients with solid tumors: a technical analysis.

PubMed

Zhou, Fangbin; Zhou, Yaying; Yang, Ming; Wen, Jinli; Dong, Jun; Tan, Wenyong

2018-01-01

Circulating endothelial cells (CECs) and their subpopulations could be potential novel biomarkers for various malignancies. However, reliable enumerable methods are warranted to further improve their clinical utility. This study aimed to optimize a flow cytometric method (FCM) assay for CECs and subpopulations in peripheral blood for patients with solid cancers. An FCM assay was used to detect and identify CECs. A panel of 60 blood samples, including 44 metastatic cancer patients and 16 healthy controls, were used in this study. Some key issues of CEC enumeration, including sample material and anticoagulant selection, optimal titration of antibodies, lysis/wash procedures of blood sample preparation, conditions of sample storage, sufficient cell events to enhance the signal, fluorescence-minus-one controls instead of isotype controls to reduce background noise, optimal selection of cell surface markers, and evaluating the reproducibility of our method, were integrated and investigated. Wilcoxon and Mann-Whitney U tests were used to determine statistically significant differences. In this validation study, we refined a five-color FCM method to detect CECs and their subpopulations in peripheral blood of patients with solid tumors. Several key technical issues regarding preanalytical elements, FCM data acquisition, and analysis were addressed. Furthermore, we clinically validated the utility of our method. The baseline levels of mature CECs, endothelial progenitor cells, and activated CECs were higher in cancer patients than healthy subjects ( P <0.01). However, there was no significant difference in resting CEC levels between healthy subjects and cancer patients ( P =0.193). We integrated and comprehensively addressed significant technical issues found in previously published assays and validated the reproducibility and sensitivity of our proposed method. Future work is required to explore the potential of our optimized method in clinical oncologic applications.

Comparison of carbon dioxide and air insufflation during consecutive EGD and colonoscopy in moderate-sedation patients: a prospective, double-blind, randomized controlled trial.

PubMed

Kim, Su Young; Chung, Jun-Won; Park, Dong Kyun; Kwon, Kwang An; Kim, Kyoung Oh; Kim, Yoon Jae; Kim, Jung Ho

2017-06-01

Endoscopy is performed with air insufflation and is usually associated with abdominal pain. It is well recognized that carbon dioxide (CO 2 ) is absorbed more quickly into the body than air; however, to date, few studies have investigated the use of CO 2 insufflation during consecutive EGD and colonoscopy (CEC). Thus, this study evaluated the efficacy of CO 2 insufflation compared with air insufflation in CEC. From March 2014 to April 2016, a total of 215 consecutive patients were randomly assigned to receive CO 2 insufflation (CO 2 group, n = 108) or air insufflation (air group, n = 107). Abdominal pain after CEC was recorded on a visual analogue scale (VAS). The amount of sedatives administered, use of analgesics, polyp detection rate (PDR), adenoma detection rate (ADR), abdominal circumference, and adverse events were also analyzed. Baseline patient characteristics were not significantly different between the groups. Abdominal pain on the VAS in the CO 2 group and air group 1 hour after CEC was, respectively, 13.8 and 20.1 (P = .010), 3 hours after CEC was 8.3 and 12.5 (P = .056), 6 hours after CEC was 3.5 and 5.3 (P = .246), and 1 day after CEC was 1.8 and 3.4 (P = .192). The dose of sedative administered, analgesic usage, PDR, ADR, and adverse events were not statistically different between the groups. However, the increase in abdominal circumference was significantly higher in the air group than in the CO 2 group. CO 2 insufflation was superior to air insufflation with regard to the pain score on the VAS in the hour after CEC. (Clinical trial registration number: KCT0001491.). Copyright © 2017 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Cytologic characteristics of circulating epithelioid cells in pancreatic disease.

PubMed

Rosenbaum, Matthew W; Cauley, Christy E; Kulemann, Birte; Liss, Andrew S; Castillo, Carlos Fernandez-Del; Warshaw, Andrew L; Lillemoe, Keith D; Thayer, Sarah P; Pitman, Martha B

2017-05-01

Circulating epithelioid cells (CECs), also known as circulating tumor, circulating cancer, circulating epithelial, or circulating nonhematologic cells, are a prognostic factor in various malignancies that can be isolated via various protocols. In the current study, the authors analyzed the cytomorphologic characteristics of CECs isolated by size in a cohort of patients with benign and malignant pancreatic diseases to determine whether cytomorphological features could predict CEC origin. Blood samples were collected from 9 healthy controls and 171 patients with pancreatic disease who were presenting for surgical evaluation before treatment. Blood was processed with the ScreenCell size-based filtration device. Evaluable CECs were analyzed in a blinded fashion for cytomorphologic characteristics, including cellularity; nucleoli; nuclear size, irregularity, variability, and hyperchromasia; and nuclear-to-cytoplasmic ratio. Statistical differences between variables were analyzed via the Fisher exact test. No CECs were identified among the 9 normal healthy controls. Of the 115 patients with CECs (positive or suspicious for), 25 had nonmalignant disease and 90 had malignancy. There were no significant differences in any of the cytologic criteria noted between groups divided by benign versus malignant, neoplastic versus nonneoplastic, or pancreatic ductal adenocarcinoma versus neuroendocrine tumor. CECs were observed in patients with malignant and nonmalignant pancreatic disease, but not in healthy controls. There were no morphologic differences observed between cells from different pancreatic diseases, suggesting that numerous conditions may be associated with CECs in the circulation and that care must be taken not to overinterpret cells identified by cytomorphology as indicative of circulating tumor cells of pancreatic cancer. Additional studies are required to determine the origin and clinical significance of these cells. Cancer Cytopathol 2017;125:332-340. © 2017

EFFECTS OF FOREFOOT RUNNING ON CHRONIC EXERTIONAL COMPARTMENT SYNDROME: A CASE SERIES

PubMed Central

Gregory, Robert; Alitz, Curtis; Gerber, J. Parry

2011-01-01

Introduction: Chronic exertional compartment syndrome (CECS) is a condition that occurs almost exclusively with running whereby exercise increases intramuscular pressure compromising circulation, prohibiting muscular function, and causing pain in the lower leg. Currently, a lack of evidence exists for the effective conservative management of CECS. Altering running mechanics by adopting forefoot running as opposed to heel striking may assist in the treatment of CECS, specifically with anterior compartment symptoms. Case Description: The purpose of this case series is to describe the outcomes for subjects with CECS through a systematic conservative treatment model focused on forefoot running. Subject one was a 21 y/o female with a 4 year history of CECS and subject two was a 21 y/o male, 7 months status-post two-compartment right leg fasciotomy with a return of symptoms and a new onset of symptoms on the contralateral side. Outcome: Both subjects modified their running technique over a period of six weeks. Kinematic and kinetic analysis revealed increased step rate while step length, impulse, and peak vertical ground reaction forces decreased. In addition, leg intracompartmental pressures decreased from pre-training to post-training. Within 6 weeks of intervention subjects increased their running distance and speed absent of symptoms of CECS. Follow-up questionnaires were completed by the subjects at 7 months following intervention; subject one reported running distances up to 12.87 km pain-free and subject two reported running 6.44 km pain-free consistently 3 times a week. Discussion: This case series describes a potentially beneficial conservative management approach to CECS in the form of forefoot running instruction. Further research in this area is warranted to further explore the benefits of adopting a forefoot running technique for CECS as well as other musculoskeletal overuse complaints. PMID:22163093

Prognostic Value of CD109+ Circulating Endothelial Cells in Recurrent Glioblastomas Treated with Bevacizumab and Irinotecan

PubMed Central

Cuppini, Lucia; Calleri, Angelica; Bruzzone, Maria Grazia; Prodi, Elena; Anghileri, Elena; Pellegatta, Serena; Mancuso, Patrizia; Porrati, Paola; Di Stefano, Anna Luisa; Ceroni, Mauro; Bertolini, Francesco; Finocchiaro, Gaetano; Eoli, Marica

2013-01-01

Background Recent data suggest that circulating endothelial and progenitor cells (CECs and CEPs, respectively) may have predictive potential in cancer patients treated with bevacizumab, the antibody recognizing vascular endothelial growth factor (VEGF). Here we report on CECs and CEPs investigated in 68 patients affected by recurrent glioblastoma (rGBM) treated with bevacizumab and irinotecan and two Independent Datasets of rGBM patients respectively treated with bevacizumab alone (n=32, independent dataset A: IDA) and classical antiblastic chemotherapy (n=14, independent dataset B: IDB). Methods rGBM patients with KPS ≥50 were treated until progression, as defined by MRI with RANO criteria. CECs expressing CD109, a marker of tumor endothelial cells, as well as other CEC and CEP subtypes, were investigated by six-color flow cytometry. Results A baseline count of CD109+ CEC higher than 41.1/ml (1st quartile) was associated with increased progression free survival (PFS; 20 versus 9 weeks, P=0.008) and overall survival (OS; 32 versus 23 weeks, P=0.03). Longer PFS (25 versus 8 weeks, P=0.02) and OS (27 versus 17 weeks, P=0.03) were also confirmed in IDA with CD109+ CECs higher than 41.1/ml but not in IDB. Patients treated with bevacizumab with or without irinotecan that were free from MRI progression after two months of treatment had significant decrease of CD109+ CECs: median PFS was 19 weeks; median OS 29 weeks. The presence of two non-contiguous lesions (distant disease) at baseline was an independent predictor of shorter PFS and OS (P<0.001). Conclusions Data encourage further studies on the predictive potential of CD109+ CECs in GBM patients treated with bevacizumab. PMID:24069296

Effects of forefoot running on chronic exertional compartment syndrome: a case series.

PubMed

Diebal, Angela R; Gregory, Robert; Alitz, Curtis; Gerber, J Parry

2011-12-01

Chronic exertional compartment syndrome (CECS) is a condition that occurs almost exclusively with running whereby exercise increases intramuscular pressure compromising circulation, prohibiting muscular function, and causing pain in the lower leg. Currently, a lack of evidence exists for the effective conservative management of CECS. Altering running mechanics by adopting forefoot running as opposed to heel striking may assist in the treatment of CECS, specifically with anterior compartment symptoms. The purpose of this case series is to describe the outcomes for subjects with CECS through a systematic conservative treatment model focused on forefoot running. Subject one was a 21 y/o female with a 4 year history of CECS and subject two was a 21 y/o male, 7 months status-post two-compartment right leg fasciotomy with a return of symptoms and a new onset of symptoms on the contralateral side. Both subjects modified their running technique over a period of six weeks. Kinematic and kinetic analysis revealed increased step rate while step length, impulse, and peak vertical ground reaction forces decreased. In addition, leg intracompartmental pressures decreased from pre-training to post-training. Within 6 weeks of intervention subjects increased their running distance and speed absent of symptoms of CECS. Follow-up questionnaires were completed by the subjects at 7 months following intervention; subject one reported running distances up to 12.87 km pain-free and subject two reported running 6.44 km pain-free consistently 3 times a week. This case series describes a potentially beneficial conservative management approach to CECS in the form of forefoot running instruction. Further research in this area is warranted to further explore the benefits of adopting a forefoot running technique for CECS as well as other musculoskeletal overuse complaints.

Estimation of soil cation exchange capacity using Genetic Expression Programming (GEP) and Multivariate Adaptive Regression Splines (MARS)

NASA Astrophysics Data System (ADS)

Emamgolizadeh, S.; Bateni, S. M.; Shahsavani, D.; Ashrafi, T.; Ghorbani, H.

2015-10-01

The soil cation exchange capacity (CEC) is one of the main soil chemical properties, which is required in various fields such as environmental and agricultural engineering as well as soil science. In situ measurement of CEC is time consuming and costly. Hence, numerous studies have used traditional regression-based techniques to estimate CEC from more easily measurable soil parameters (e.g., soil texture, organic matter (OM), and pH). However, these models may not be able to adequately capture the complex and highly nonlinear relationship between CEC and its influential soil variables. In this study, Genetic Expression Programming (GEP) and Multivariate Adaptive Regression Splines (MARS) were employed to estimate CEC from more readily measurable soil physical and chemical variables (e.g., OM, clay, and pH) by developing functional relations. The GEP- and MARS-based functional relations were tested at two field sites in Iran. Results showed that GEP and MARS can provide reliable estimates of CEC. Also, it was found that the MARS model (with root-mean-square-error (RMSE) of 0.318 Cmol+ kg-1 and correlation coefficient (R2) of 0.864) generated slightly better results than the GEP model (with RMSE of 0.270 Cmol+ kg-1 and R2 of 0.807). The performance of GEP and MARS models was compared with two existing approaches, namely artificial neural network (ANN) and multiple linear regression (MLR). The comparison indicated that MARS and GEP outperformed the MLP model, but they did not perform as good as ANN. Finally, a sensitivity analysis was conducted to determine the most and the least influential variables affecting CEC. It was found that OM and pH have the most and least significant effect on CEC, respectively.

Fracture Strength of Endodontically Treated Teeth with Different Access Cavity Designs.

PubMed

Plotino, Gianluca; Grande, Nicola Maria; Isufi, Almira; Ioppolo, Pietro; Pedullà, Eugenio; Bedini, Rossella; Gambarini, Gianluca; Testarelli, Luca

2017-06-01

The purpose of this study was to compare in vitro the fracture strength of root-filled and restored teeth with traditional endodontic cavity (TEC), conservative endodontic cavity (CEC), or ultraconservative "ninja" endodontic cavity (NEC) access. Extracted human intact maxillary and mandibular premolars and molars were selected and assigned to control (intact teeth), TEC, CEC, or NEC groups (n = 10/group/type). Teeth in the TEC group were prepared following the principles of traditional endodontic cavities. Minimal CECs and NECs were plotted on cone-beam computed tomographic images. Then, teeth were endodontically treated and restored. The 160 specimens were then loaded to fracture in a mechanical material testing machine (LR30 K; Lloyd Instruments Ltd, Fareham, UK). The maximum load at fracture and fracture pattern (restorable or unrestorable) were recorded. Fracture loads were compared statistically, and the data were examined with analysis of variance and the Student-Newman-Keuls test for multiple comparisons. The mean load at fracture for TEC was significantly lower than the one for the CEC, NEC, and control groups for all types of teeth (P < .05), whereas no difference was observed among CEC, NEC, and intact teeth (P > .05). Unrestorable fractures were significantly more frequent in the TEC, CEC, and NEC groups than in the control group in each tooth type (P < .05). Teeth with TEC access showed lower fracture strength than the ones prepared with CEC or NEC. Ultraconservative "ninja" endodontic cavity access did not increase the fracture strength of teeth compared with the ones prepared with CEC. Intact teeth showed more restorable fractures than all the prepared ones. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Combined Raman and SEM study on CaF2 formed on/in enamel by APF treatments.

PubMed

Tsuda, H; Jongebloed, W L; Stokroos, I; Arends, J

1993-01-01

Raman spectra containing the distinct band at 322 cm-1 due to CaF2 or CaF2-like material formed in/on fluoridated bovine enamel were recorded using a micro-Raman spectrograph. Due to increasing levels of background fluorescence with increasing thickness of enamel, the Raman measurements were carried out on thin regions of wedged enamel sections. The distribution of the CaF2 or CaF2-like material was estimated using a simple model. The results indicate that 1/3 of the total CaF2 was concentrated within the narrow depth < 2 microns with high CaF2 concentrations (> 10 wt%), and that the majority of the CaF2 was distributed over the depths up to 26 microns (1 wt% CaF2). SEM observations on fractured fluoridated enamel confirmed that morphological changes were present in the depth range comparable to that of the high CaF2 concentration region expected from the Raman analysis. In deeper regions where lower concentration (< 10%) but a large amount of CaF2 was still expected, the SEM images failed to distinguish between the normal and fluoridated enamel. After KOH treatment, the Raman spectra did not show evidence of the CaF2 peak and the SEM micrographs also confirmed the removal of globules. The peak position of the Raman band of the CaF2 formed by the fluoridation was identical to that of pure CaF2. However, the linewidth was 23 cm-1 (FWHM) and a factor of 2 broader than that of pure CaF2 (12 cm-1). This implies that the lattice dynamics of the CaF2 formed by fluoridation is different from of pure CaF2, and that the material formed is 'CaF2-like' or 'disordered CaF2'.

Mechatronic Development and Vision Feedback Control of a Nanorobotics Manipulation System inside SEM for Nanodevice Assembly

PubMed Central

Yang, Zhan; Wang, Yaqiong; Yang, Bin; Li, Guanghui; Chen, Tao; Nakajima, Masahiro; Sun, Lining; Fukuda, Toshio

2016-01-01

Carbon nanotubes (CNT) have been developed in recent decades for nanodevices such as nanoradios, nanogenerators, carbon nanotube field effect transistors (CNTFETs) and so on, indicating that the application of CNTs for nanoscale electronics may play a key role in the development of nanotechnology. Nanorobotics manipulation systems are a promising method for nanodevice construction and assembly. For the purpose of constructing three-dimensional CNTFETs, a nanorobotics manipulation system with 16 DOFs was developed for nanomanipulation of nanometer-scale objects inside the specimen chamber of a scanning electron microscope (SEM). Nanorobotics manipulators are assembled into four units with four DOFs (X-Y-Z-θ) individually. The rotational one is actuated by a picomotor. That means a manipulator has four DOFs including three linear motions in the X, Y, Z directions and a 360-degree rotational one (X-Y-Z-θ stage, θ is along the direction rotating with X or Y axis). Manipulators are actuated by picomotors with better than 30 nm linear resolution and <1 micro-rad rotary resolution. Four vertically installed AFM cantilevers (the axis of the cantilever tip is vertical to the axis of electronic beam of SEM) served as the end-effectors to facilitate the real-time observation of the operations. A series of kinematic derivations of these four manipulators based on the Denavit-Hartenberg (D-H) notation were established. The common working space of the end-effectors is 2.78 mm by 4.39 mm by 6 mm. The manipulation strategy and vision feedback control for multi-manipulators operating inside the SEM chamber were been discussed. Finally, application of the designed nanorobotics manipulation system by successfully testing of the pickup-and-place manipulation of an individual CNT onto four probes was described. The experimental results have shown that carbon nanotubes can be successfully picked up with this nanorobotics manipulation system. PMID:27649180

Mechatronic Development and Vision Feedback Control of a Nanorobotics Manipulation System inside SEM for Nanodevice Assembly.

PubMed

Yang, Zhan; Wang, Yaqiong; Yang, Bin; Li, Guanghui; Chen, Tao; Nakajima, Masahiro; Sun, Lining; Fukuda, Toshio

2016-09-14

Carbon nanotubes (CNT) have been developed in recent decades for nanodevices such as nanoradios, nanogenerators, carbon nanotube field effect transistors (CNTFETs) and so on, indicating that the application of CNTs for nanoscale electronics may play a key role in the development of nanotechnology. Nanorobotics manipulation systems are a promising method for nanodevice construction and assembly. For the purpose of constructing three-dimensional CNTFETs, a nanorobotics manipulation system with 16 DOFs was developed for nanomanipulation of nanometer-scale objects inside the specimen chamber of a scanning electron microscope (SEM). Nanorobotics manipulators are assembled into four units with four DOFs (X-Y-Z-θ) individually. The rotational one is actuated by a picomotor. That means a manipulator has four DOFs including three linear motions in the X, Y, Z directions and a 360-degree rotational one (X-Y-Z-θ stage, θ is along the direction rotating with X or Y axis). Manipulators are actuated by picomotors with better than 30 nm linear resolution and <1 micro-rad rotary resolution. Four vertically installed AFM cantilevers (the axis of the cantilever tip is vertical to the axis of electronic beam of SEM) served as the end-effectors to facilitate the real-time observation of the operations. A series of kinematic derivations of these four manipulators based on the Denavit-Hartenberg (D-H) notation were established. The common working space of the end-effectors is 2.78 mm by 4.39 mm by 6 mm. The manipulation strategy and vision feedback control for multi-manipulators operating inside the SEM chamber were been discussed. Finally, application of the designed nanorobotics manipulation system by successfully testing of the pickup-and-place manipulation of an individual CNT onto four probes was described. The experimental results have shown that carbon nanotubes can be successfully picked up with this nanorobotics manipulation system.

Helping Students and the Bottom Line: Creating a Module-Based Academic Program to Drive SEM Goals

ERIC Educational Resources Information Center

Levine, Jeffrey P.

2012-01-01

The chief academic officer to whom the author once reported gave him the freedom to be creative in implementing their institution's then-new, three-year strategic enrollment management (SEM) plan. For the fall 2010 semester, they had already exceeded projected net-tuition dollar amounts for the entire academic year. Just five months prior to…

The Structure of Memory in Infants and Toddlers: An SEM Study with Full-Terms and Preterms

ERIC Educational Resources Information Center

Rose, Susan A.; Feldman, Judith F.; Jankowski, Jeffery J.; Van Rossem, Ronan

2011-01-01

There is considerable dispute about the nature of infant memory. Using SEM models, we examined whether popular characterizations of the structure of adult memory, including the two-process theory of recognition, are applicable in the infant and toddler years. The participants were a cohort of preterms and full-terms assessed longitudinally--at 1,…

Three-Phase 3D Reconstruction of a LiCoO 2 Cathode via FIB-SEM Tomography

DOE PAGES

Liu, Zhao; Chen-Wiegart, Yu-chen K.; Wang, Jun; ...

2016-01-14

Three-phase three-dimensional (3D) microstructural reconstructions of lithium-ion battery electrodes are critical input for 3D simulations of electrode lithiation/delithiation, which provide a detailed understanding of battery operation. In this report, 3D images of a LiCoO 2electrode are achieved using focused ion beam-scanning electron microscopy (FIB-SEM), with clear contrast among the three phases: LiCoO 2particles, carbonaceous phases (carbon and binder) and the electrolyte space. The good contrast was achieved by utilizing an improved FIB-SEM sample preparation method that combined infiltration of the electrolyte space with a low-viscosity silicone resin and triple ion-beam polishing. Morphological parameters quantified include phase volume fraction, surface area,more » feature size distribution, connectivity, and tortuosity. Electrolyte tortuosity was determined using two different geometric calculations that were in good agreement. In conclusion, the electrolyte tortuosity distribution versus position within the electrode was found to be highly inhomogeneous; this will lead to inhomogeneous electrode lithiation/delithiation at high C-rates that could potentially cause battery degradation.« less

Coastal surface sediment quality assessment in Leizhou Peninsula (South China Sea) based on SEM-AVS analysis.

PubMed

Li, Feng; Lin, Jin-qin; Liang, Yan-yan; Gan, Hua-yang; Zeng, Xiang-yun; Duan, Zhi-peng; Liang, Kai; Liu, Xing; Huo, Zhen-hai; Wu, Chang-hua

2014-07-15

Surface sediments from the coastal area of the Leizhou Peninsula in the South China Sea were collected and analyzed and the potential ecological risks in the area were assessed based on acid-volatile sulfide (AVS) model. The AVS levels are between 0.109 and 55.6 μmol g(-1), with the average at 4.45 μmol g(-1). The high AVS-concentration zones include the aquaculture areas of Liusha Bay and the densely populated areas of Zhanjiang Bay. The simultaneously extracted metals (SEM) range from 0.026 μmol g(-1) to 8.61 μmol g(-1), with the average at 0.843 μmol g(-1). Most of high SEM-concentration stations were located in ports or aquaculture zones. Most of the coastal surface sediments of the Leizhou Peninsula (90%) had no adverse biological effects according to the criterion proposed by USEPA (2005); while adverse effects were uncertain in some stations (8%); even in 2 stations (2%) adverse biological effects may be expected. Copyright © 2014 Elsevier Ltd. All rights reserved.

SEM Based CARMA Time Series Modeling for Arbitrary N.

PubMed

Oud, Johan H L; Voelkle, Manuel C; Driver, Charles C

2018-01-01

This article explains in detail the state space specification and estimation of first and higher-order autoregressive moving-average models in continuous time (CARMA) in an extended structural equation modeling (SEM) context for N = 1 as well as N > 1. To illustrate the approach, simulations will be presented in which a single panel model (T = 41 time points) is estimated for a sample of N = 1,000 individuals as well as for samples of N = 100 and N = 50 individuals, followed by estimating 100 separate models for each of the one-hundred N = 1 cases in the N = 100 sample. Furthermore, we will demonstrate how to test the difference between the full panel model and each N = 1 model by means of a subject-group-reproducibility test. Finally, the proposed analyses will be applied in an empirical example, in which the relationships between mood at work and mood at home are studied in a sample of N = 55 women. All analyses are carried out by ctsem, an R-package for continuous time modeling, interfacing to OpenMx.

[4 years of Microbiología SEM (1994-1997)].

PubMed

Mas-Castellà, J

1997-12-01

Different aspects of Microbiología SEM editorial process over the years 1994-1997 are analyzed: number of originals received, the process leading to their publication, rates of accepted and refused papers, time needed for each step of the editorial process--which comprises scientific, language editing, if needed--, as well as some characteristics that can define the patterns of the articles, such as number of authors, institutions where the authors work and mean number of references. The contents of the different sections (editorial, research and review articles, perspectives, opinion, books review) are commented on, as well as the role played by some of them as forums for the discussion of topics of current scientific interest, especially the editorials focusing on the state-of-the-art of microbiological research in Latin American countries. Characteristics and frequency of monographic issues are also presented. The information is complemented with data about the circulation and distribution of the journal, its inclusion in international indexes and its current electronic publication on the world wide web.

A comparison of sediment quality results with acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) ratio in Vojvodina (Serbia) sediments.

PubMed

Prica, M; Dalmacija, B; Roncević, S; Krcmar, D; Becelić, M

2008-01-25

The acid-volatile sulfide (AVS), simultaneously extracted metals (SEM), total metals, and pore-water metal concentrations were studied in Vojvodina (Serbia) sediments. In Serbia, there are no regulations concerning sediment quality standards and sediment management. Harmonization of legislation in the domain of environmental protection with EU requirements will increase the significance of the sediment issue. Sediment quality was assessed according to Dutch standards, but the results were also compared with Canadian and USEPA (United States Environmental Protection Agency) guidelines for sediment quality. A comparison of the results based on different criteria for sediment quality assessment shows that they are sometimes contradictory. Therefore, a single approach to quality assessment may be insufficient. The Sigma[SEM]/[AVS] ratio was found to be greater than one at several locations that were already recognized as places of high risk based on Dutch standards. Some other samples had Sigma[SEM]/[AVS]<1, despite of the high risk classification based on the Dutch evaluation. However, not all sediments with Sigma[SEM]/[AVS]>1 can cause increased toxicity because there are many other metal-binding phases in sediments. Metals that are associated with AVS may be released within sediments through storms, dredging activities, oxidation, etc., and may have adverse environmental impacts. This has to be taken into account during dredging, which is for some sediments necessary because the sediment is of class 4 (Dutch evaluation), because the dredging process will certainly increase the concentration of bioavailable heavy metals and disturb the sedimentation dynamics. The obtained results will be invaluable for future activities regarding dredging and sediment management in the country.

[Circulating endothelial cells--markers of blood vessel lesions in patients with diffuse liver disease].

PubMed

Dynnik, O B

2006-01-01

The increased level of the circulating endothelial cells (CEC) is in direct dependance with a degree of an endothelial trauma. We defined CEC in blood (cells x 104/L) of 67 adults and children with acute and chronic viral hepatitis (A and B) and healthy volontiars. The author obtained reliable results of increased CEC in all groups consisting of patients with diffuse liver deseases (17,4+/-6,5 and 19,8+/-8,4) in comparison with control groups (3,8+/-1,9 and 3,8+/-1,2) thus CEC can be of practical value as a marker of microvessel lesions of the liver. Endotheliocytemia testifies to be a factor during endothelial trauma in pathogenesis of diffuse liver disease.

A study of biochemical route on construction of waste battery ferrite applying for nickel removal.

PubMed

Niu, Zhirui; Zhang, Shaokang; Zhu, Lin

2018-05-21

Mn-Zn ferrite (Mn 1 - x Zn x Fe 2 O 4 , x = 0.2, 0.4, 0.6, and 0.8) nanomaterials were prepared by bioleaching and hydrothermal synthesis from waste Zn-Mn batteries. The materials were characterized by XRD, SEM, BET, VSM, CEC, and isoelectric point. It turned out when x = 0.4, synthesized Mn-Zn ferrite had best performance which was nanoferrite crystal structure with a specific surface area that reached 37.77 m 2 /g, the saturation magnetization was 62.85 emu/g, and isoelectric point and the CEC value were 7.33 and 43.51 mmol/100 g, respectively. In addition, the adsorption characteristics on Ni 2+ were explored. The results of experiment suggested that data was more in line with the Freundlich model compared with Langmuir and Dubinin-Radushkevich isotherm models. Kinetics studies showed that pseudo-second-order kinetics was more suitable for describing the Ni 2+ adsorption process where the maximum theoretical adsorption quantity was 52.99 mg/g. Thermodynamic parameters indicated the adsorption process can be spontaneous as an endothermic reaction, and warming was advantageous to adsorption. Besides, the adsorbent could be reused for six cycles with high removal efficiency. The magnetic and adsorptive properties of the adsorbent were promising, which had a high application value. Graphical abstract Fabrication process of nanometer ferrite by biological technology and hydrothermal synthesis for removal of Ni2.

Characterization of zeolites synthesized from porous wastes using hydrothermal agitational leaching assisted by magnetic separation

NASA Astrophysics Data System (ADS)

Top, Soner; Vapur, Huseyin; Ekicibil, Ahmet

2018-07-01

In this study, zeolite Na-P1 synthesis from the fly ashes (FA) taken from dust catcher in Sugözü thermic power plant was researched. The structural and magnetic characteristics of the synthesized materials were studied by using the XRD, SEM, EDS, CEC, TGA, DTA, DSC and M-H techniques. High intensity wet magnetic separation was applied to the ashes at different magnetic field intensities. 61% of the iron oxide impurity (Fe2O3) was removed by single-stage high intensity wet magnetic separation at 1.5 T. Non-magnetic phase was accumulated in order to leach in alkali medium. 2 M NaOH was used as the synthesizing solution. Solid-liquid ratio was 0.3 kg:1 L. It was determined that the zeolitization degrees of the products depend on the reaction time. Zeolite Na-P1 (Na6Al6Si10O32·12H2O) which is the member of the group P zeolites was the dominant species after 10 h reaction time. Additionally, gismondine (Ca2Al4Si4O16·9H2O) presence was observed in the products. It was found out that the ferromagnetisms of the products were weakened by elapsed time. The CEC values of the synthesized products were the superior grades ranging from 269.63 meq/100 g to 388.85 meq/100 g.

Programmatically Optimized SEM Image Acquisition for Measurement of Contamination on Molybdenum Coated Foils from the NASA Genesis Mission

NASA Astrophysics Data System (ADS)

Gil, A.

2016-12-01

The NASA Genesis Mission flew high-purity collector materials on a satellite from 2001-2004 to collect a sample of the solar wind. Upon return to Earth, a spacecraft malfunction caused the onboard sample materials to be severely contaminated during the crash landing in the Utah desert. As part of an ongoing effort to decontaminate the collector materials, they are being scanned with a scanning electron microscope (SEM) to determine the amount of dirt and spacecraft debris contaminating the collectors. This effort is underway currently, but we have identified an opportunity to improve the quality of the SEM data collected. At present, many small images are acquired and stitched together to form larger images of Genesis collector pieces, which are then analyzed. The collectors are physically distorted, however, and the imaging method presently used doesn't allow imaging parameters to be adjusted between images to correct for this distortion. In order to improve the quality of the collected imaging, we are developing a program to acquire a focus map of each sample prior to image collection. The program then uses this data to adjust the position of the sample in the SEM to image all sections in focus and at a constant focal length. This is accomplished using the Python programming language, and the programmatic interface built into our Tescan VEGA Scanning Electron Microscope. Our approach, progress to date, and challenges are discussed.

SEM fractography studies of porous vitreous carbon: a candidate biomaterial.

PubMed

Tarr, R R

1979-09-01

A new porous vitreous carbon material under development for use in orthopedic applications was investigated. Specimens were machined to appropriate sizes and fractured in one of the following modes: compression, cantilevered bending, or axial torsion. Scanning electron microscopy (SEM) was used to examine surface and internal features. Characteristics of a brittle, glassy material were noted. Findings included internal voids which appeared as craters, patches of whiskerlike fibrils, and edge impurities. Numerous microcracks caused by mechanical shaping and handling were the most remarkable structural defects. Pore channels which would allow bony ingrowth ranged in size from 50--500 micrometers with the majority between 200 and 300 micrometers. This study of porous vitreous carbon points to the need for stricter quality control in manufacturing, alternative methods for shaping and handling, and careful consideration in design and usage of a brittle material with marginal limits of safety for biomedical applications.

Surface interactions on hydrogel contact lenses: scanning electron microscopy (SEM).

PubMed

Hart, D E

1987-12-01

SEM was used to visualize tear-film/hydrogel polymer surface interactions. Lenses were preserved by fixation including a quaternary ammonium complex to aid in mucin preservation. In less than 2 weeks of continuous wear the anterior surface was completely coated, yet the coating was absent from the posterior lens surface. Tear-film break-up over the deposited lens surface, combined with degradation and deformation at the polymer surface boundary, as well as entrapment of moieties within the polymer matrix, all occurred. These are the likely culprits which can contribute to adverse reactions as well as cause light scatter and diminished vision. Lenses removed directly from the eyes of patients suffering with different forms of conjunctivitis were obtained. Bacterial and viral conjunctivitis can induce a microbially contaminated as well as a heavily deformed and deposited lens. Viable and intact microbes were not typically observed in the mucoprotein layer of hydrogel contact lenses.

Evidence for the involvement of NOD2 in regulating colonic epithelial cell growth and survival.

PubMed

Cruickshank, Sheena-M; Wakenshaw, Louise; Cardone, John; Howdle, Peter-D; Murray, Peter-J; Carding, Simon-R

2008-10-14

To investigate the function of NOD2 in colonic epithelial cells (CEC). A combination of in vivo and in vitro analyses of epithelial cell turnover in the presence and absence of a functional NOD2 protein and, in response to enteric Salmonella typhimurium infection, were used. shRNA interference was also used to investigate the consequences of knocking down NOD2 gene expression on the growth and survival of colorectal carcinoma cell lines. In the colonic mucosa the highest levels of NOD2 expression were in proliferating crypt epithelial cells. Muramyl dipeptide (MDP), that is recognized by NOD2, promoted CEC growth in vitro. By contrast, the growth of NOD2-deficient CECs was impaired. In vivo CEC proliferation was also reduced and apoptosis increased in Nod2(-/-) mice, which were also evident following enteric Salmonella infection. Furthermore, neutralization of NOD2 mRNA expression in human colonic carcinoma cells by shRNA interference resulted in decreased survival due to increased levels of apoptosis. These findings are consistent with the involvement of NOD2 protein in promoting CEC growth and survival. Defects in proliferation by CECs in cases of CD may contribute to the underlying pathology of disrupted intestinal homeostasis and excessive inflammation.

Evidence for the involvement of NOD2 in regulating colonic epithelial cell growth and survival

PubMed Central

Cruickshank, Sheena M; Wakenshaw, Louise; Cardone, John; Howdle, Peter D; Murray, Peter J; Carding, Simon R

2008-01-01

AIM: To investigate the function of NOD2 in colonic epithelial cells (CEC). METHODS: A combination of in vivo and in vitro analyses of epithelial cell turnover in the presence and absence of a functional NOD2 protein and, in response to enteric Salmonella typhimurium infection, were used. shRNA interference was also used to investigate the consequences of knocking down NOD2 gene expression on the growth and survival of colorectal carcinoma cell lines. RESULTS: In the colonic mucosa the highest levels of NOD2 expression were in proliferating crypt epithelial cells. Muramyl dipeptide (MDP), that is recognized by NOD2, promoted CEC growth in vitro. By contrast, the growth of NOD2-deficient CECs was impaired. In vivo CEC proliferation was also reduced and apoptosis increased in Nod2-/- mice, which were also evident following enteric Salmonella infection. Furthermore, neutralization of NOD2 mRNA expression in human colonic carcinoma cells by shRNA interference resulted in decreased survival due to increased levels of apoptosis. CONCLUSION: These findings are consistent with the involvement of NOD2 protein in promoting CEC growth and survival. Defects in proliferation by CECs in cases of CD may contribute to the underlying pathology of disrupted intestinal homeostasis and excessive inflammation. PMID:18855982

Epistemology of Contaminants of Emerging Concern and Literature Meta-analysis

PubMed Central

Halden, Rolf U.

2014-01-01

A meta-analysis was conducted to inform the epistemology, or theory of knowledge, of contaminants of emerging concern (CECs). The CEC terminology acknowledges the existence of harmful environmental agents whose identities, occurrences, hazards, and effects are not sufficiently understood. Here, data on publishing activity were analyzed for 12 CECs, revealing a common pattern of emergence, suitable for identifying past years of peak concern and forecasting future ones: dichlorodiphenyltrichloroethane (DDT; 1972, 2008), trichloroacetic acid (TCAA; 1972, 2009), nitrosodimethylamine (1984), methyl tert-butyl ether (2001), trichloroethylene (2005), perchlorate (2006), 1,4-dioxane (2009), prions (2009), triclocarban (2010), triclosan (2012), nanomaterials (by 2016), and microplastics (2022 ± 4). CECs were found to emerge from obscurity to the height of concern in 14.1 ± 3.6 years, and subside to a new baseline level of concern in 14.5 ± 4.5 years. CECs can emerge more than once (e.g., TCAA, DDT) and the multifactorial process of emergence may be driven by inception of novel scientific methods (e.g., ion chromatography, mass spectrometry and nanometrology), scientific paradigm shifts (discovery of infectious proteins), and the development, marketing and mass consumption of novel products (antimicrobial personal care products, microplastics and nanomaterials). Publishing activity and U.S. regulatory actions were correlated for several CECs investigated. PMID:25294779

Ecosystem Models as Support to Eutrophication Management in the North Atlantic Ocean (EMoSEM)

NASA Astrophysics Data System (ADS)

Lacroix, Geneviève; Billen, Gilles; Desmit, Xavier; Garnier, Josette; Gypens, Nathalie; Lancelot, Christiane; Lenhart, Hermann; Los, Hans; Mateus, Marcos; Ménesguen, Alain; Neves, Ramiro; Troost, Tineke; van der Molen, Johan

2013-04-01

One of the leading challenges in marine science and governance is to improve scientific guidance of management measures to mitigate eutrophication nuisances in the EU seas. Existing approaches do not integrate the eutrophication process in space (continuum river-ocean) and in time (past, present and future status). A strong need remains for (i) knowledge/identification of all the processes that control eutrophication and its consequences, (ii) consistent and harmonized reference levels assigned to each eutrophication-related indicator, (iii) identification of the main rivers directly or indirectly responsible for eutrophication nuisances in specific areas, (iv) an integrated transboundary approach and (v) realistic and scientific-based nutrient reduction scenarios. The SEAS-ERA project EMoSEM aims to develop and combine the state-of-the-art modelling tools describing the river-ocean continuum in the North-East Atlantic (NEA) continental seas. This will allow to link the eutrophication nuisances in specific marine regions to anthropogenic inputs, trace back their sources up to the watersheds, then test nutrient reduction options that might be implemented in these watersheds, and propose consistent indicators and reference levels to assess the Good Environmental Status (GES). At the end, EMoSEM will deliver coupled river-coastal-sea mathematical models and will provide guidance to end-users (policy- and decision makers) for assessing and combating eutrophication problems in the NEA continental waters.

Identification of possible sources of particulate matter in the personal cloud using SEM/EDX

NASA Astrophysics Data System (ADS)

Conner, Teri L.; Williams, Ronald W.

2004-10-01

The United States Environmental Protection Agency (US EPA) conducted the Baltimore Particulate Matter (PM) Epidemiology-Exposure Study of the Elderly during the summer of 1998. The study design included PM2.5 samples obtained from elderly (65+ years of age) retirement facility residents using personal exposure sampling devices. These sampling devices were also used to obtain PM2.5 samples at fixed locations within the personal monitoring subjects' apartments. Selected personal and apartment samples were examined using scanning electron microscopy with individual-particle X-ray analysis (SEM/EDX), providing a qualitative assessment of the chemical and physical characteristics of geological and trace element particles collected within these micro-environments at the retirement facility. This information was used to identify possible indoor source particles. The manual surveys of the personal samples revealed that some particles larger than 2.5 μm reached the filter surface. Using SEM/EDX, several particle types with possible indoor origins were identified. The Al-Zr-Cl particle is likely to have originated from a personal antiperspirant product. Particles with a talc or alumino-silicate composition point to cosmetics as a possible source. Large cadmium-containing particles were also found, which may indicate the use of art pigments or ceramic glazes, or emissions from television screen phosphors. A greater variety of particles was observed in a personal sample compared with its corresponding fixed-location apartment sample.

Graphene-supporting films and low-voltage STEM in SEM toward imaging nanobio materials without staining: Observation of insulin amyloid fibrils.

PubMed

Ogawa, Takashi; Gang, Geun Won; Thieu, Minh Thu; Kwon, Hyuksang; Ahn, Sang Jung; Ha, Tai Hwan; Cho, Boklae

2017-05-01

Utilization of graphene-supporting films and low-voltage scanning transmission electron microscopy (LV-STEM) in scanning electron microscopy (SEM) is shown to be an effective means of observing unstained nanobio materials. Insulin amyloid fibrils, which are implicated as a cause of type II diabetes, are formed in vitro and observed without staining at room temperature. An in-lens cold field-emission SEM, equipped with an additional homemade STEM detector, provides dark field (DF)-STEM images in the low energy range of 5-30keV, together with secondary electron (SE) images. Analysis based on Lenz's theory is used to interpret the experimental results. Graphene films, where the fibrils are deposited, reduce the background level of the STEM images compared with instances when conventional amorphous carbon films are used. Using 30keV, which is lower than that for conventional TEM (100-300keV), together with low detection angles (15-55mrad) enhances the signals from the fibrils. These factors improve image quality, which enables observation of thin fibrils with widths of 7-8nm. STEM imaging clearly reveals a twisted-ribbon structure of a fibril, and SE imaging shows an emphasized striped pattern of the fibril. The LV-STEM in SEM enables acquisition of two types of images of an identical fibril in a single instrument, which is useful for understanding the structure. This study expands the application of SEM to other systems of interest, which is beneficial to a large number of users. The method in this study can be applied to the observation of various nanobio materials and analysis of their native structures, thus contributing to research in materials and life sciences. Copyright © 2017 Elsevier Ltd. All rights reserved.

AxiSEM3D: a new fast method for global wave propagation in 3-D Earth models with undulating discontinuities

NASA Astrophysics Data System (ADS)

Leng, K.; Nissen-Meyer, T.; van Driel, M.; Al-Attar, D.

2016-12-01

We present a new, computationally efficient numerical method to simulate global seismic wave propagation in realistic 3-D Earth models with laterally heterogeneous media and finite boundary perturbations. Our method is a hybrid of pseudo-spectral and spectral element methods (SEM). We characterize the azimuthal dependence of 3-D wavefields in terms of Fourier series, such that the 3-D equations of motion reduce to an algebraic system of coupled 2-D meridional equations, which can be solved by a 2-D spectral element method (based on www.axisem.info). Computational efficiency of our method stems from lateral smoothness of global Earth models (with respect to wavelength) as well as axial singularity of seismic point sources, which jointly confine the Fourier modes of wavefields to a few lower orders. All boundary perturbations that violate geometric spherical symmetry, including Earth's ellipticity, topography and bathymetry, undulations of internal discontinuities such as Moho and CMB, are uniformly considered by means of a Particle Relabeling Transformation.The MPI-based high performance C++ code AxiSEM3D, is now available for forward simulations upon 3-D Earth models with fluid outer core, ellipticity, and both mantle and crustal structures. We show novel benchmarks for global wave solutions in 3-D mantle structures between our method and an independent, fully discretized 3-D SEM with remarkable agreement. Performance comparisons are carried out on three state-of-the-art tomography models, with seismic period going down to 5s. It is shown that our method runs up to two orders of magnitude faster than the 3-D SEM for such settings, and such computational advantage scales favourably with seismic frequency. By examining wavefields passing through hypothetical Gaussian plumes of varying sharpness, we identify in model-wavelength space the limits where our method may lose its advantage.

Circulating endothelial cells and their progenitors in acute myeloid leukemia

PubMed Central

Zahran, Asmaa Mohammed; Aly, Sanaa Shaker; Altayeb, Hanan Ahmed; Ali, Arwa Mohammed