Preparation and evaluation of carvacrol pellets based on PVP solid-dispersion by extrusion-spheronization technique

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Z. Taghizadeh*

2017-11-01

Full Text Available Background and objectives: Carvacrol is one of the main pharmacologically active components of Thymus vulgaris essential oil which has shown several therapeutic effects. There are few works regarding the formulation of essential oils as oral solid dosage forms due to their liquid nature, stability and technical problems. The aim of this study was to combine the solid-dispersion approach and extrusion-spheronization technique to produce pellets with desirable physico-mechanical and release properties. Methods: Solid dispersion matrix (30% of carvacrol in polyvinylpyrrolidone K30 was prepared by solvent evaporation. The matrix was mixed with Avicel and lactose and granulated by water. The wet mass was transformed into pellets by extrusion-spheronization. In order to compare the solid dispersion method with the classic approaches, another pellet formulation was prepared by absorption of carvacrol on Aerosil. The pellets were characterized for size (sieve analysis, shape factors (image analysis, mechanical strength, carvacrol content, and release rate (dissolution test. Accelerated stability test of formulations was also carried out. Results: Using suitable composition of solid dispersion matrix and granulation fluid, the pellets with desirable size and shape and mechanical properties could be produced. PVP-based pellets had higher mechanical strength, slower release rate and improved content and stability. The PVP ratio showed considerable effect on release properties of the pellets. Conclusion: Overall, the results revealed the feasibility of preparing desirable pellets containing carvacrol with acceptable content, stability and release properties which can be administered as hard gelatin capsules.

Comparison of in situ polymerization and solution-dispersion techniques in the preparation of Polyimide/Montmorillonite (MMT) Nanocomposites.

Science.gov (United States)

Ahmad, Mansor Bin; Gharayebi, Yadollah; Salit, Mohd Sapuan; Hussein, Mohd Zobir; Shameli, Kamyar

2011-01-01

In this paper, Polyimide/Montmorillonite Nanocomposites (PI/MMT NCs), based on aromatic diamine (4-Aminophenyl sulfone) (APS) and aromatic dianhydride (3,3',4,4'-benzophenonetetracarboxylic dianhydride) (BTDA) were prepared using in situ polymerization and solution-dispersion techniques. The prepared PI/MMT NCs films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The XRD results showed that at the content of 1.0 wt % Organo Montmorillonite (OMMT) for two techniques and 3.0 wt % OMMT for the in situ polymerization technique, the OMMT was well-intercalated, exfoliated and dispersed into polyimide matrix. The OMMT agglomerated when its amount exceeded 10 wt % and 3.0 wt % for solution-dispersion and in situ polymerization techniques respectively. These results were confirmed by the TEM images of the prepared PI/MMT NCs. The TGA thermograms indicated that thermal stability of prepared PI/MMT NCs were increased with the increase of loading that, the effect is higher for the samples prepared by in situ polymerization technique.

Sample preparation techniques for (p, X) spectrometry

International Nuclear Information System (INIS)

Whitehead, N.E.

1985-01-01

Samples are ashed at low temperature, using oxygen plasma; a rotary evaporator, and freeze drying speeded up the ashing. The new design of apparatus manufactured was only 10 watt but was as efficient as a 200 watt commercial machine; a circuit diagram is included. Samples of hair and biopsy samples of skin were analysed by the technique. A wool standard was prepared for interlaboratory comparison exercises. It was based on New Zealand merino sheep wool and was 2.9 kg in weight. A washing protocol was developed, which preserves most of the trace element content. The wool was ground in liquid nitrogen using a plastic pestle and beaker, driven by a rotary drill press. (author)

Preparation of Risedronate Nanoparticles by Solvent Evaporation Technique

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Eliska Vaculikova

2014-11-01

Full Text Available One approach for the enhancement of oral drug bioavailability is the technique of nanoparticle preparation. Risedronate sodium (Biopharmaceutical Classification System Class III was chosen as a model compound with high water solubility and low intestinal permeability. Eighteen samples of risedronate sodium were prepared by the solvent evaporation technique with sodium dodecyl sulfate, polysorbate, macrogol, sodium carboxymethyl cellulose and sodium carboxymethyl dextran as nanoparticle stabilizers applied in three concentrations. The prepared samples were characterized by dynamic light scattering and scanning electron microscopy. Fourier transform mid-infrared spectroscopy was used for verification of the composition of the samples. The particle size of sixteen samples was less than 200 nm. Polysorbate, sodium carboxymethyl dextran and macrogol were determined as the most favourable excipients; the particle size of the samples of risedronate with these excipients ranged from 2.8 to 10.5 nm.

Technique for preparation of anaerobic microbes: Rodshaped cellulolytic bacteria

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Amlius Thalib

2001-10-01

Full Text Available Preparation of anaerobic-rod cellulolytic bacteria with coating technique has been conducted. Steps of the processes involved were cultivation, coating, evaporation, and drying. Coating agent used was Gum Arabic, and drying techniquesconducted were freeze drying and sun drying. pH of culture media was firstly optimized to obtain the maximal population ofbacteria. Both coated and uncoated preparates were subjected to drying. Morphological and Gram type identifications showed that uncoated preparate dried with freeze drying is not contaminated (ie. all bacteria are rod shape with Gram-negative type while the one dried with sun drying is not morphologically pure (ie. containing of both rod and coccus shapes with Gram negative and positive. The coated preparates dried by both freeze and sun drying, were not contaminated (ie. all are rods with Gram-negative. The coating and drying processes decreased viability of preparates significantly. However, the decreasing of viability of coated preparate are lower than uncoated preparate (ie. 89 vs. 97%. Total count of bacteria in sun-drying coated preparate are higher (P<0.05 than the uncoated preparate (ie. 3.38 x 1010 vs. 1.97 x 1010 colony/g DM. Activity of sun-drying coated preparate to digest elephant grass and rice straw was higher (P<0.01 than the sun-drying uncoated preparate with the in vitro DMD values were 42.7 vs. 35.5% for elephant grass substrate and 29.3 vs. 24.6% for rice straw substrate. Therefore, it is concluded that coating technique has a positive effects on the preparation of rumen bacteria.

Preparation and comparison of a-C:H coatings using reactive sputter techniques

Energy Technology Data Exchange (ETDEWEB)

Keunecke, M., E-mail: martin.keunecke@ist.fraunhofer.d [Fraunhofer Institute for Surface Engineering and Thin Films (IST), Braunschweig (Germany); Weigel, K.; Bewilogua, K. [Fraunhofer Institute for Surface Engineering and Thin Films (IST), Braunschweig (Germany); Cremer, R.; Fuss, H.-G. [CemeCon AG, Wuerselen (Germany)

2009-12-31

Amorphous hydrogenated carbon (a-C:H) coatings are widely used in several industrial applications. These coatings commonly will be prepared by plasma activated chemical vapor deposition (PACVD). The main method used to prepare a-C:H coating in industrial scale is based on a glow discharge in a hydrocarbon gas like acetylene or methane using a substrate electrode powered with medium frequency (m.f. - some 10 to 300 kHz). Some aims of further development are adhesion improvement, increase of hardness and high coating quality on complex geometries. A relatively new and promising technique to fulfil these requirements is the deposition of a-C:H coatings by a reactive d.c. magnetron sputter deposition from a graphite target with acetylene as reactive gas. An advancement of this technique is the deposition in a pulsed magnetron sputter process. Using these three mentioned techniques a-C:H coatings were prepared in the same deposition machine. For adhesion improvement different interlayer systems were applied. The effect of different substrate bias voltages (d.c. and d.c. pulse) was investigated. By applying the magnetron sputter technique in the d.c. pulse mode, plastic hardness values up to 40 GPa could be reached. Besides hardness other mechanical properties like resistance against abrasive wear were measured and compared. Cross sectional SEM images showed the growth structure of the coatings.

New trends in sample preparation techniques for environmental analysis.

Science.gov (United States)

Ribeiro, Cláudia; Ribeiro, Ana Rita; Maia, Alexandra S; Gonçalves, Virgínia M F; Tiritan, Maria Elizabeth

2014-01-01

Environmental samples include a wide variety of complex matrices, with low concentrations of analytes and presence of several interferences. Sample preparation is a critical step and the main source of uncertainties in the analysis of environmental samples, and it is usually laborious, high cost, time consuming, and polluting. In this context, there is increasing interest in developing faster, cost-effective, and environmentally friendly sample preparation techniques. Recently, new methods have been developed and optimized in order to miniaturize extraction steps, to reduce solvent consumption or become solventless, and to automate systems. This review attempts to present an overview of the fundamentals, procedure, and application of the most recently developed sample preparation techniques for the extraction, cleanup, and concentration of organic pollutants from environmental samples. These techniques include: solid phase microextraction, on-line solid phase extraction, microextraction by packed sorbent, dispersive liquid-liquid microextraction, and QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe).

Sample preparation for special PIE-techniques at ITU

International Nuclear Information System (INIS)

Toscano, E.H.; Manzel, R.

2002-01-01

Several sample preparation techniques were developed and installed in hot cells. The techniques were conceived to evaluate the performance of highly burnt fuel rods and include: (a) a device for the removal of the fuel, (b) a method for the preparation of the specimen ends for the welding of new end caps and for the careful cleaning of samples for Transmission Electron Microscopy and Glow Discharge Mass Spectroscopy, (c) a sample pressurisation device for long term creep tests, and (d) a diameter measuring device for creep or burst samples. Examples of the determination of the mechanical properties, the behaviour under transient conditions and for the assessment of the corrosion behaviour of high burnup cladding materials are presented. (author)

METHODOLOGY OF TECHNIQUE PREPARATION FOR LOW VISION JAVELIN THROWERS

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Milan Matić

2013-07-01

Full Text Available Javelin throwing discipline for disabled people has been expanding couple of years back. In addition, world’s records have been improving year after year. The esential part in preparation of low vision javelin throwers is mastering the technique elements, crucial for acquiring better results. Method of theoretical analysis, decriptive and comparative methods of survey were applied. Relevant knowledge in the area of low vision javelin throwers was analyzed and systematized, and then interpretated theoretically and applied on the top javelin thrower, which served as a base for the inovative apporoach in methodology and praxis with disabled people. Due to visual impairment, the coordination and balance are challenged. This limitation practically makes the difference in methodology, explained in this article. Apart from the goals focused on improving the condition and results on competitions, more specialized goals should be considered, e.g. improving of orientation, balance and socialization process for the people who have low vision. Special approach used in the technique preparation brought the significant improvement in techique of our famous Paralympian Grlica Miloš. In addition to the technique improvement he acquired better results on the big competitions and a few worldwide valuable prizes were won. The area of ’sport for disabled people’ is not enough present in the praxis of sport’s workers. More articles and scientific surveys on this topic are needed for further work and results improvement with these kind of sportsmen.

Characteristics of nanosized zirconia prepared by plasma and chemical technique

International Nuclear Information System (INIS)

Kuznetsova, L.; Grabis, J.; Heidemane, G.

2003-01-01

The studied preparation method of zirconia using the plasma technique, azeotropic distillation and glycine routes ensure obtaining of nano sized powders with close average particle size but different crystallite size and phase composition. The sinterability of nano sized zirconia particles prepared by plasma technique or wet-chemical methods is similar and depends on the green density of pressed powders, improvement of with can be achieved by using of granulated precursors. (authors)

The Recent Developments in Sample Preparation for Mass Spectrometry-Based Metabolomics.

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Gong, Zhi-Gang; Hu, Jing; Wu, Xi; Xu, Yong-Jiang

2017-07-04

Metabolomics is a critical member in systems biology. Although great progress has been achieved in metabolomics, there are still some problems in sample preparation, data processing and data interpretation. In this review, we intend to explore the roles, challenges and trends in sample preparation for mass spectrometry- (MS-) based metabolomics. The newly emerged sample preparation methods were also critically examined, including laser microdissection, in vivo sampling, dried blood spot, microwave, ultrasound and enzyme-assisted extraction, as well as microextraction techniques. Finally, we provide some conclusions and perspectives for sample preparation in MS-based metabolomics.

Evaluation of the maladaptation of the test base in acrylic resin regarding the technique of preparation, place of measurement and storage time

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Natália Pereira de OLIVEIRA

2018-02-01

Full Text Available Abstract Introduction The most used material for the preparation of the baseplates is the acrylic resin, but it can present distortions. Objective To evaluate preparation technique, region and storage time that presents less maladaptation of the base when made with self-cured acrylic resin. Material and method Models were created in gypsum type III simulating edentulous maxilla, as divided into 3 groups (n = 10: GC (control group thermopolymerizable acrylic resin; G1 - manual adaptation technique and G2 - drip technique. For the measurements, silicone by condensation of light consistency that was interposed between base and model was used. With a hydraulic press, 50 kg pressure was applied leading the base of the model. The obtained mold was measured in the palate, canine and molar regions with a digital caliper at the following times: immediately after the base polymerization, at 24, 48, 72, 96 hours and one week. The results were submitted to statistical analysis. Result G1 presented maladaptation of 0.43 mm ± 0.10, while G2 obtained 0.39 mm ± 0.11. The lowest maladaptation occurred in the CG. The palate region presented greater maladaptation (0.52 ± 0.07 and the canine region, the lowest (CD = 0.27 mm ± 0.07 and CE = 0.27 ± 0.09; There was no statistically significant difference for storage times. Conclusion G2 presented lower values than G1, with no statistically significant difference. The palate region presented greater maladaptation, followed by molars and canines. The bases continued to maladaptation the model after the immediate polymerization, with no statistically significant difference.

Impact of pig insemination technique and semen preparation on profitability.

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Gonzalez-Peña, D; Knox, R V; Pettigrew, J; Rodriguez-Zas, S L

2014-01-01

Artificial insemination technique and semen preparation impact boar utilization efficiency, genetic dissemination, and biosecurity. Intrauterine (IUI) and deep intrauterine (DUI) AI techniques require lower number of spermatozoa per dose compared to conventional (CON) AI. Frozen semen (FRO) has been associated with lower reproductive performance compared to fresh semen (FRE) preparation. The combined effects of 3 AI techniques (CON, IUI, and DUI) and 2 semen preparations (FRE and FRO) on the financial indicators of a pig crossbreeding system were studied. A 3-tier system was simulated in ZPLAN and the genetic improvement in a representative scenario was characterized. The cross of nucleus lines B and A generated 200,000 BA sows at the multiplier level. The BA sows were inseminated (CON, IUI, or DUI) with FRE or FRO from line C boars at the commercial level. Semen preparation and AI technique were represented by distinct sow:boar ratios in the C × BA cross. A range of farrowing rates (60 to 90%) and litter sizes (8 to 14 liveborn pigs) were tested. Genetic improvement per year for number born alive, adjusted 21-d litter weight, days to 113.5 kg, backfat, and ADG were 0.01 pigs per litter, 0.06 kg, -0.09 d, -0.29 mm, and 0.88 g, respectively. On average, the net profit for FRE (FRO) increased (P-value profit between techniques were driven by differences in costs. Differences in fixed costs between IUI and DUI relative to CON were -2.4 (-5.2%) and -3.4% (-7.4%), respectively. The differences in total costs between FRE and FRO were lower than -5%. The difference in variable costs between FRE and FRO ranged from -5.3 (CON) to -24.7% (DUI). Overall, insemination technique and semen preparation had a nonlinear effect on profit. The average relative difference in profit between FRE and FRO was less than 3% for the scenarios studied.

Immunological consequences of using three different clinical/laboratory techniques of emulsifying peptide-based vaccines in incomplete Freund's adjuvant

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Kast W Martin

2006-10-01

Full Text Available Abstract Incomplete Freund's adjuvant (IFA serves as a carrier for water-in-oil emulsion (W/O vaccines. The stability of such emulsions greatly affects vaccine safety and efficacy since continued presence of antigen depots at lymphoid organs releasing low-level antigens is known to stimulate a potent immune response and high-level systemic release of antigens can lead to tolerance. W/O emulsions for the purpose of clinical and laboratory peptide-based vaccinations have been prepared using the techniques of syringe extrusion, vortex or high-speed homogenization. There is no consensus in the field over which technique would be best to use and no immunological data are available that compare the three techniques. In this study, we compared the immune responses induced by a peptide-based vaccine prepared using vortex, syringe-extrusion and homogenization. The vaccination led to tumor rejection by mice vaccinated with the peptide-based vaccine prepared using all three techniques. The immunological data from the in vivo cytotoxicity assay showed a trend for lower responses and a higher variability and greater range in the immune responses induced by a vaccine that was emulsified by the vortex or homogenizer techniques as compared to the syringe-extrusion technique. There were statistically significant lower numbers of IFNγ-secreting cells induced when the mice were vaccinated with a peptide-based vaccine emulsion prepared using the vortex compared to the syringe-extrusion technique. At a suboptimal vaccine dose, the mice vaccinated with a peptide-based vaccine emulsion prepared using the vortex technique had the largest tumors compared to the syringe-extrusion or the homogenizer technique. In the setting of a busy pharmacy that prepares peptide-based vaccine emulsions for clinical studies, the vortex technique can still be used but we urge investigators to take special care in their choice of mixing vessels for the vortex technique as that can

Development of ion beam sputtering techniques for actinide target preparation

International Nuclear Information System (INIS)

Aaron, W.S.; Zevenbergen, L.A.; Adair, H.L.

1985-01-01

Ion beam sputtering is a routine method for the preparation of thin films used as targets because it allows the use of minimum quantity of starting material, and losses are much lower than most other vacuum deposition techniques. Work is underway in the Isotope Research Materials Laboratory (IRML) at ORNL to develop the techniques that will make the preparation of actinide targets up to 100 μg/cm 2 by ion beam sputtering a routinely available service from IRML. The preparation of the actinide material in a form suitable for sputtering is a key to this technique, as is designing a sputtering system that allows the flexibility required for custom-ordered target production. At present, development work is being conducted on low-activity in a bench-top system. The system will then be installed in a hood or glove box approved for radioactive materials handling where processing of radium, actinium, and plutonium isotopes among others will be performed. (orig.)

Development of ion beam sputtering techniques for actinide target preparation

Science.gov (United States)

Aaron, W. S.; Zevenbergen, L. A.; Adair, H. L.

1985-06-01

Ion beam sputtering is a routine method for the preparation of thin films used as targets because it allows the use of a minimum quantity of starting material, and losses are much lower than most other vacuum deposition techniques. Work is underway in the Isotope Research Materials Laboratory (IRML) at ORNL to develop the techniques that will make the preparation of actinide targets up to 100 μg/cm 2 by ion beam sputtering a routinely available service from IRML. The preparation of the actinide material in a form suitable for sputtering is a key to this technique, as is designing a sputtering system that allows the flexibility required for custom-ordered target production. At present, development work is being conducted on low-activity actinides in a bench-top system. The system will then be installed in a hood or glove box approved for radioactive materials handling where processing of radium, actinium, and plutonium isotopes among others will be performed.

The OPPIuM technique: office hysteroscopic technique for the preparation of partially intramural leiomyomas.

Science.gov (United States)

Cicinelli, Ettore; Mitsopoulos, Vasileios; Fascilla, Fabiana D; Sioutis, Dimos; Bettocchi, Stefano

2016-06-01

Uterine fibroids, also known as leiomyomas, represent the most common benign tumors of the female genital tract. Submucosal leiomyomas are classified into three grades: G0, GI, GII according to the degree of their intramural proportion. A recently developed technique enables the preparation of G1 and G2 leiomyomas for their subsequent successful resection in a second step. The OPPIuM (office preparation of partially intramural leiomyomas) technique aims to downgrade type I and II leiomyomas, in order to facilitate a subsequent easier and safer resectoscopy. Hysteroscopic resection of large GI or GII submucosal fibroids is a complex procedure. OPPIuM technique has been invented and seems to achieve the downgrading of these types of leiomyomas in approximately 93% of cases, without any significant surgical complications or the need of hormonal agents' administration. In this way, the safer and quicker subsequent complete myomectomy is facilitated.

Albendazole Microparticles Prepared by Spray Drying Technique ...

African Journals Online (AJOL)

Purpose: To enhance the dissolution of albendazole (ABZ) using spray-drying technique. Method: ABZ binary mixtures with Kollicoat IR® (KL) and polyvinyl pyrrolidone (PVP) in various drug to polymer ratios (1: 1, 1: 2 and 1; 4) were prepared by spray-drying. The spray-dried particles were characterized for particle shape, ...

A one-step technique to prepare aligned arrays of carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Mahanandia, Pitamber [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Nanda, Karuna Kar [Materials Research Centre, Indian Institute of Science, Bangalore 560012 (India)], E-mail: pitam@physics.iisc.ernet.in

2008-04-16

A simple effective pyrolysis technique has been developed to synthesize aligned arrays of multi-walled carbon nanotubes (MWCNTs) without using any carrier gas in a single-stage furnace at 700 deg. C. This technique eliminates nearly the entire complex and expensive machinery associated with other extensively used methods for preparation of CNTs such as chemical vapour deposition (CVD) and pyrolysis. Carbon source materials such as xylene, cyclohexane, camphor, hexane, toluene, pyridine and benzene have been pyrolyzed separately with the catalyst source material ferrocene to obtain aligned arrays of MWCNTs. The synthesized CNTs have been characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. In this technique, the need for the tedious and time-consuming preparation of metal catalysts and continuously fed carbon source material containing carrier gas can be avoided. This method is a single-step process where not many parameters are required to be monitored in order to prepare aligned MWCNTs. For the production of CNTs, the technique has great advantages such as low cost and easy operation.

Marginal adaptation of CAD-CAM onlays: Influence of preparation design and impression technique.

Science.gov (United States)

Lima, Fernanda Ferruzzi; Neto, Constantino Fernandes; Rubo, José H; Santos, Gildo Coelho; Moraes Coelho Santos, Maria Jacinta

2018-03-15

Factors that may affect the marginal adaptation of computer-aided design and computer-aided manufacturing (CAD-CAM) restorations include preparation design, impression technique, and CAD-CAM system. The influence of impression technique and preparation design on CAD-CAM partial coverage restorations has not been fully addressed. The purpose of this in vitro study was to investigate the influence of direct and indirect digital impression techniques and 2 preparation designs on the marginal adaptation of CAD-CAM onlays. Two mesio-occlusal buccal onlay preparations with reduction of the mesiobuccal cusp were made: conventional preparation (CP) with a 1.2-mm modified shoulder margin and modified preparation (MP) flat cuspal reduction without shoulder. Virtual models were generated from each preparation by using a digital scanner (BlueCam; Dentsply Sirona) from the plastic teeth (direct digital impression) or from the stone dies (indirect digital impression). Onlays were designed using a CAD-CAM system (CEREC 4.0; Dentsply Sirona), and nanoceramic resin blocks (Lava Ultimate Restorative; 3M ESPE) were milled using the CEREC MCX milling machine. Marginal discrepancy was evaluated using an optical stereomicroscope at ×25 magnification in 18 locations distributed along the margins of the preparation. The data were analyzed by using 3-way ANOVA followed by the Tukey HSD test (α=.05). CP presented a statistically significant reduced average marginal adaptation (59 ±50 μm) than did MP (69 ±58 μm) (Pmarginal discrepancy in the mesial and buccal locations of MP when compared with CP. Regarding impression techniques, the buccal location presented the smallest average marginal discrepancy in restorations fabricated with indirect impression when compared with direct impression (42 ±33 μm and 60 ±39 μm) (Pmargin presented improved marginal adaptation compared with modified preparation with flat cuspal reduction. Direct and indirect digital impression techniques produced

Optimization of a simple technique for preparation of monodisperse poly(lactide-co-glycolide) nanospheres

Energy Technology Data Exchange (ETDEWEB)

Ito, Fuminori, E-mail: fuminoito@spice.ocn.ne.jp [Tokyo Metropolitan University, Department of Applied Chemistry, Graduate School of Urban Environmental Sciences (Japan)

2016-09-15

In this study, we report the optimization of a solvent evaporation technique for preparing monodisperse poly-(lactide-co-glycolide) (PLGA) nanospheres, from a mixture of solvents composed of ethanol and PVA solution. Various experimental conditions were investigated in order to control the particle size and size distribution of the nanospheres. In addition, nanospheres containing rifampicin (RFP, an antituberculosis drug), were prepared using PLGA of various molecular weights, to study the effects of RFP as a model hydrophobic drug. The results showed that a higher micro-homogenizer stirring rate facilitated the preparation of monodisperse PLGA nanospheres with a low coefficient of variation (~20 %), with sizes below 200 nm. Increasing the PLGA concentration from 0.1 to 0.5 g resulted in an increase in the size of the obtained nanospheres from 130 to 174 nm. The molecular weight of PLGA had little effect on the particle sizes and particle size distributions of the nanospheres. However, the drug loading efficiencies of the obtained RFP/PLGA nanospheres decreased when the molecular weight of PLGA was increased. Based on these experiments, an optimized technique was established for the preparation of monodisperse PLGA nanospheres, using the method developed by the authors.Graphical Abstract.

Preparation and application of new fluorescein-labeled fumonisins B1 in fluorescence polarization analysis technique

Science.gov (United States)

Objective: To prepare a new fluorescent tracer against common mycotoxins such as fumonisin B1 in order to replace 6-(4,6-Dichlorotriazinyl) aminofluorescein (6-DTAF), an expensive marker, and to develop a technique for quick detection of fumonisin B1 based on the principle of fluorescence polarizati...

Gold nanoparticles prepared by electro-exploding wire technique in aqueous solutions

Science.gov (United States)

Kumar, Lalit; Kapoor, Akanksha; Meghwal, Mayank; Annapoorni, S.

2016-05-01

This article presents an effective approach for the synthesis of Au nanoparticles via an environmentally benevolent electro-exploding wire (EEW) technique. In this process, Au nanoparticles evolve through the plasma generated from the parent Au metal. Compared to other typical chemical methods, electro-exploding wire technique is a simple and economical technique which normally operates in water or organic liquids under ambient conditions. Efficient size control was achieved using different aqueous medium like (1mM) NaCl, deionized water and aqueous solution of sodium hydroxide (NaOH, pH 9.5) using identical electro-exploding conditions. The gold nanoparticles exhibited the UV-vis absorption spectrum with a maximum absorption band at 530 nm, similar to that of gold nanoparticles chemically prepared in a solution. The mechanism of size variation of Au nanoparticles is also proposed. The results obtained help to develop methodologies for the control of EEW based nanoparticle growth and the functionalization of nanoparticle surfaces by specific interactions.

Preparation Of Porous And Dense Bodies From Hydroxyapatite Powders Prepared Via Sol-Gel Technique

International Nuclear Information System (INIS)

Sopyan, Lis

2001-01-01

Hydroxyapatite (HA) ceramics is clinically proven and, thus, a reliable material for medical applications, that is, for use in dental and orthopedical surgery to fill cavities in bones. In this paper, we report a preliminary study on development of HA porous and dense materials manufactured using fine HA powders prepared via a sol-gel technique. In the preparation of HA porous bodies, slurries of the as-prepared powder were prepared with an adjusted loading ofHA, using Duramax of 0-3021 type as dispersant. After soaking cellulosic sponges into the slurry, the sponges were dried and then subjected to heat-treatment at 600 o C, followed by sintering at 1250 o C for I h. The apparent density of the porous bodies is 1.290 g/cm 3 , with a porosity of 59%. The sintering shrinkage is about 20% (in respect of dimension) and 44 % (in respect of volume). Morphological evaluation of the porous bodies showed that the samples contained macropores of 1-2 mm diameter and micropores of 1-2 μm diameter. The measurement of mechanical strength provided 1.31 ± 0.30 MPa. Subsequently, dense samples were prepared from the as-prepared powder. In this case, the powder was mixed with poly(vinyl alcohol) and distilled water to make a slurry. The mixture was mixed using Zirconia balls as the crusher for 2h. The suspension was then spray-dried, and well-dispersed powder was obtained. The powder was compressed uniaxially using cold pressing technique at 800 kglcm2 and the pellets obtained were sintered in air at : 250 o C for I h. The sintered dense bodies have apparent density of 2.855 g/cm 3 , with a 10% porosity. The flexural strength of the dense bodies measured on the specimens of riimension 2 mm x 2.5 mm gave rise to the considerable value of 57.7 MPa

Preparation of spherical particles by vibrating orifice technique

Science.gov (United States)

Shibata, Shuichi; Tomizawa, Atsushi; Yoshikawa, Hidemi; Yano, Tetsuji; Yamane, Masayuki

2000-05-01

Preparation of micrometer-sized spherical particles containing Rhodamine 6G (R6G) has been investigated for the spherical cavity micro-laser. Using phenyl triethoxy silane (PTES) as a starting material, R6G-doped monodisperse spherical particles were prepared by the vibrating orifice technique. Processing consists of two major processes: (1) Hydrolysis and polymerization of PTES and (2) Droplet formation from PTES oligomers by vibrating orifice technique. A cylindrical liquid jet passing through the orifice of 10 and 20 micrometers in diameter breaks up into equal- sized droplets by mechanical vibration. Alcohol solvent of these droplets was evaporated during flying with carrier gas and subsequently solidified in ammonium water trap. For making smooth surface and god shaped particles, control of molecular weight of PTES oligomer was essential. R6G-doped hybrid spherical particles of 4 to 10 micrometers size of cavity structure were successfully obtained. The spherical particles were pumped by a second harmonic pulse of Q- switched Nd:YAG laser and laser emission peaks were observed at wavelengths which correspond to the resonance modes.

Effect of Simplifying Drilling Technique on Heat Generation During Osteotomy Preparation for Dental Implant.

Science.gov (United States)

El-Kholey, Khalid E; Ramasamy, Saravanan; Kumar R, Sheetal; Elkomy, Aamna

2017-12-01

To test the hypothesis that there would be no difference in heat production by reducing the number of drills during the implant site preparation relative to conventional drilling sequence. A total of 120 implant site preparations with 3 different diameters (3.6, 4.3, and 4.6 mm) were performed on bovine ribs. Within the same diameter group, half of the preparations were performed by a simplified drilling procedure (pilot drill + final diameter drill) and other half using the conventional drilling protocol (pilot drill followed by graduated series of drills to widen the site). Heat production by different drilling techniques was evaluated by measuring the bone temperature using k-type thermocouple and a sensitive thermometer before and after each drill. Mean for maximum temperature increase during site preparation of the 3.6, 4.3, and 4.6-mm implants was 2.45, 2.60, and 2.95° when the site was prepared by the simplified procedure, whereas it was 2.85, 3.10, and 3.60° for the sites prepared by the conventional technique, respectively. No significant difference in temperature increase was found when implants of the 3 different diameters were prepared either by the conventional or simplified drilling procedure. The simplified drilling technique produced similar amount of heat comparable to the conventional technique that proved the initial hypothesis.

A technique for preparing polytene chromosomes from Aedes aegypti (Diptera, Culicinae

Directory of Open Access Journals (Sweden)

Jairo Campos

2003-04-01

Full Text Available Polytene chromosome preparations were obtained from larval, pupal and adult female Malpighian tubules of Aedes aegypti. The Malpighian tubules of the pupae (0-4 h old from larvae reared at 20ºC provided the best cytogenetic analysis. The interaction of nucleic acids and proteins that influence the spreading of the chromosomes could be reduced with the preparation technique of the sheets submitted to a stronger treatment starting with the hypotony of tissue and successive bathings with acetic acid. A simple technique should facilitate molecular cytogenetics used in the location of resistance and vector competence genes.

Optimization of fast dissolving etoricoxib tablets prepared by sublimation technique

OpenAIRE

Patel D; Patel M

2008-01-01

The purpose of this investigation was to develop fast dissolving tablets of etoricoxib. Granules containing etoricoxib, menthol, crospovidone, aspartame and mannitol were prepared by wet granulation technique. Menthol was sublimed from the granules by exposing the granules to vacuum. The porous granules were then compressed in to tablets. Alternatively, tablets were first prepared and later exposed to vacuum. The tablets were evaluated for percentage friability and disintegration time. A 3 2 ...

Microextraction sample preparation techniques in biomedical analysis.

Science.gov (United States)

Szultka, Malgorzata; Pomastowski, Pawel; Railean-Plugaru, Viorica; Buszewski, Boguslaw

2014-11-01

Biologically active compounds are found in biological samples at relatively low concentration levels. The sample preparation of target compounds from biological, pharmaceutical, environmental, and food matrices is one of the most time-consuming steps in the analytical procedure. The microextraction techniques are dominant. Metabolomic studies also require application of proper analytical technique for the determination of endogenic metabolites present in biological matrix on trace concentration levels. Due to the reproducibility of data, precision, relatively low cost of the appropriate analysis, simplicity of the determination, and the possibility of direct combination of those techniques with other methods (combination types on-line and off-line), they have become the most widespread in routine determinations. Additionally, sample pretreatment procedures have to be more selective, cheap, quick, and environmentally friendly. This review summarizes the current achievements and applications of microextraction techniques. The main aim is to deal with the utilization of different types of sorbents for microextraction and emphasize the use of new synthesized sorbents as well as to bring together studies concerning the systematic approach to method development. This review is dedicated to the description of microextraction techniques and their application in biomedical analysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Knowledge based systems advanced concepts, techniques and applications

CERN Document Server

1997-01-01

The field of knowledge-based systems (KBS) has expanded enormously during the last years, and many important techniques and tools are currently available. Applications of KBS range from medicine to engineering and aerospace.This book provides a selected set of state-of-the-art contributions that present advanced techniques, tools and applications. These contributions have been prepared by a group of eminent researchers and professionals in the field.The theoretical topics covered include: knowledge acquisition, machine learning, genetic algorithms, knowledge management and processing under unc

Review of sample preparation techniques for the analysis of pesticide residues in soil.

Science.gov (United States)

Tadeo, José L; Pérez, Rosa Ana; Albero, Beatriz; García-Valcárcel, Ana I; Sánchez-Brunete, Consuelo

2012-01-01

This paper reviews the sample preparation techniques used for the analysis of pesticides in soil. The present status and recent advances made during the last 5 years in these methods are discussed. The analysis of pesticide residues in soil requires the extraction of analytes from this matrix, followed by a cleanup procedure, when necessary, prior to their instrumental determination. The optimization of sample preparation is a very important part of the method development that can reduce the analysis time, the amount of solvent, and the size of samples. This review considers all aspects of sample preparation, including extraction and cleanup. Classical extraction techniques, such as shaking, Soxhlet, and ultrasonic-assisted extraction, and modern techniques like pressurized liquid extraction, microwave-assisted extraction, solid-phase microextraction and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) are reviewed. The different cleanup strategies applied for the purification of soil extracts are also discussed. In addition, the application of these techniques to environmental studies is considered.

Barium titanate thick films prepared by screen printing technique

Directory of Open Access Journals (Sweden)

Mirjana M. Vijatović

2010-06-01

Full Text Available The barium titanate (BaTiO3 thick films were prepared by screen printing technique using powders obtained by soft chemical route, modified Pechini process. Three different barium titanate powders were prepared: i pure, ii doped with lanthanum and iii doped with antimony. Pastes for screen printing were prepared using previously obtained powders. The thick films were deposited onto Al2O3 substrates and fired at 850°C together with electrode material (silver/palladium in the moving belt furnace in the air atmosphere. Measurements of thickness and roughness of barium titanate thick films were performed. The electrical properties of thick films such as dielectric constant, dielectric losses, Curie temperature, hysteresis loop were reported. The influence of different factors on electrical properties values was analyzed.

Preparation techniques for ceramic waste form powder

International Nuclear Information System (INIS)

Hash, M.C.; Pereira, C.; Lewis, M.A.

1997-01-01

The electrometallurgical treatment of spent nuclear fuels result in a chloride waste salt requiring geologic disposal. Argonne National Laboratory (ANL) is developing ceramic waste forms which can incorporate this waste. Currently, zeolite- or sodalite-glass composites are produced by hot isostatic pressing (HIP) techniques. Powder preparations include dehydration of the raw zeolite powders, hot blending of these zeolite powders and secondary additives. Various approaches are being pursued to achieve adequate mixing, and the resulting powders have been HIPed and characterized for leach resistance, phase equilibria, and physical integrity

Molecular Imprinting Techniques Used for the Preparation of Biosensors

Directory of Open Access Journals (Sweden)

Gizem Ertürk

2017-02-01

Full Text Available Molecular imprinting is the technology of creating artificial recognition sites in polymeric matrices which are complementary to the template in their size, shape and spatial arrangement of the functional groups. Molecularly imprinted polymers (MIPs and their incorporation with various transducer platforms are among the most promising approaches for detection of several analytes. There are a variety of molecular imprinting techniques used for the preparation of biomimetic sensors including bulk imprinting, surface imprinting (soft lithography, template immobilization, grafting, emulsion polymerization and epitope imprinting. This chapter presents an overview of all of these techniques with examples from particular publications.

ProTaper rotary instrument fracture during root canal preparation: a comparison between rotary and hybrid techniques.

Science.gov (United States)

Farid, Huma; Khan, Farhan Raza; Rahman, Munawar

2013-03-01

This study aimed to compare the frequency of ProTaper rotary instrument fracture with rotary (conventional) and hybrid (rotary and hand files) canal preparation techniques. Secondary objectives were to determine whether there was an association of ProTaper file fracture with the canal curvature and to compare the mean time required for canal preparation in the two techniques. An in vitro experiment was conducted on 216 buccal canals of extracted maxillary and mandibular first molars. After creating an access cavity and a glide path for each canal, a periapical radiograph was taken and the canal curvature was measured with Schneider's technique. The canals were then randomly divided into Group A (rotary technique) and Group B (hybrid technique). The length of ProTaper files were measured before and after each canal preparation. Time taken for each canal preparation was recorded. A total of seven ProTaper files fractured in Group A (P=0.014) in canals with a curvature >25 degrees (PProTaper rotary files, although time consuming, was safer in canals having a curvature greater than 25 degrees.

Preparation and Characterization of Astaxanthin Nanoparticles by Solvent-Diffusion Technique

International Nuclear Information System (INIS)

Anarjan, N.; Tan, C.P.

2011-01-01

In this work, astaxanthin nanoparticles were prepared in aqueous media using solvent-diffusion technique. Sodium caseinate, gelatin, Polysorbate 20 and gum Arabic were selected as different food grade surface active molecules for the stabilization of the produced nanoparticles. Results showed that among produced astaxanthin nanoparticles, the Polysorbate 20-stabilized nanoparticles showed the smallest particle size; gum Arabic-stabilized nanoparticles had the smallest polydispersity index and highest physical stability in simulated gastric fluid (SGF); and those stabilized using gelatin had the highest zeta potential. Sodium caseinate stabilized nanoparticles had the highest astaxanthin content in fresh samples as compared to other prepared nano dispersions. (author)

Textured surface structures formed using new techniques on transparent conducting Al-doped zinc oxide films prepared by magnetron sputtering

International Nuclear Information System (INIS)

Minami, Tadatsugu; Miyata, Toshihiro; Uozaki, Ryousuke; Sai, Hitoshi; Koida, Takashi

2016-01-01

Surface-textured Al-doped ZnO (AZO) films formed using two new techniques based on magnetron sputtering deposition were developed by optimizing the light scattering properties to be suitable for transparent electrode applications in thin-film silicon solar cells. Scrambled egg-like surface-textured AZO films were prepared using a new texture formation technique that post-etched pyramidal surface-textured AZO films prepared under deposition conditions suppressing c-axis orientation. In addition, double surface-textured AZO films were prepared using another new texture formation technique that completely removed, by post-etching, the pyramidal surface-textured AZO films previously prepared onto the initially deposited low resistivity AZO films; simultaneously, the surface of the low resistivity films was slightly etched. However, the obtained very high haze value in the range from the near ultraviolet to visible light in the scrambled egg-like surface-textured AZO films did not contribute significantly to the obtainable photovoltaic properties in the solar cells fabricated using the films. Significant light scattering properties as well as a low sheet resistance could be achieved in the double surface-textured AZO films. In addition, a significant improvement of external quantum efficiency in the range from the near ultraviolet to visible light was achieved in superstrate-type n-i-p μc-Si:H solar cells fabricated using a double surface-textured AZO film prepared under optimized conditions as the transparent electrode. - Highlights: • Double surface-textured AZO films prepared using a new texture formation technique • Extensive light scattering properties with low sheet resistance achieved in the double surface-textured AZO films • Improved external quantum efficiency of μc-Si:H solar cells using a double surface-textured AZO film

Textured surface structures formed using new techniques on transparent conducting Al-doped zinc oxide films prepared by magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Minami, Tadatsugu [Optoelectronic Device System R& D Center, Kanazawa Institute of Technology, Nonoichi, Ishikawa 921-8501 (Japan); Miyata, Toshihiro, E-mail: tmiyata@neptune.kanazawa-it.ac.jp [Optoelectronic Device System R& D Center, Kanazawa Institute of Technology, Nonoichi, Ishikawa 921-8501 (Japan); Uozaki, Ryousuke [Optoelectronic Device System R& D Center, Kanazawa Institute of Technology, Nonoichi, Ishikawa 921-8501 (Japan); Sai, Hitoshi; Koida, Takashi [Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan)

2016-09-01

Surface-textured Al-doped ZnO (AZO) films formed using two new techniques based on magnetron sputtering deposition were developed by optimizing the light scattering properties to be suitable for transparent electrode applications in thin-film silicon solar cells. Scrambled egg-like surface-textured AZO films were prepared using a new texture formation technique that post-etched pyramidal surface-textured AZO films prepared under deposition conditions suppressing c-axis orientation. In addition, double surface-textured AZO films were prepared using another new texture formation technique that completely removed, by post-etching, the pyramidal surface-textured AZO films previously prepared onto the initially deposited low resistivity AZO films; simultaneously, the surface of the low resistivity films was slightly etched. However, the obtained very high haze value in the range from the near ultraviolet to visible light in the scrambled egg-like surface-textured AZO films did not contribute significantly to the obtainable photovoltaic properties in the solar cells fabricated using the films. Significant light scattering properties as well as a low sheet resistance could be achieved in the double surface-textured AZO films. In addition, a significant improvement of external quantum efficiency in the range from the near ultraviolet to visible light was achieved in superstrate-type n-i-p μc-Si:H solar cells fabricated using a double surface-textured AZO film prepared under optimized conditions as the transparent electrode. - Highlights: • Double surface-textured AZO films prepared using a new texture formation technique • Extensive light scattering properties with low sheet resistance achieved in the double surface-textured AZO films • Improved external quantum efficiency of μc-Si:H solar cells using a double surface-textured AZO film.

Preparation, Characterization and application of Alumina Powder Produced by advanced Preparation Techniques

International Nuclear Information System (INIS)

Khalil, T.; Abou El Nour, F.; Bossert, J.; Ashor, A.H.

2000-01-01

Aluminum oxide powders were prepared by advanced chemical techniques. The morphology of the produced powders were examined using scanning electron microscopy (SEM). Surface characteristics of the powders were measured through nitrogen gas adsorption and application of the BET equation at 77 K, through the use of nitrogen gas adsorption at liquid nitrogen temperature and application of the Brunauer-Emett-Teller (BET) equation. The total surface area, total pore volume and pore radius of the powders were calculated through the construction of the plots relating the amount of nitrogen gas adsorbed V 1 and the thickness of the adsorbed layer t(V 1 -t plots). The thermal behaviour of the powders were studied with the help of differential thermal analysis (DTA) and thermogravimetry (TG). Due to the presence of some changes in the DTA base lines, possibly as a result of phase transformations, X-ray diffraction was applied to identify these phases. The sintering behaviour of the compact powders after isostatic pressing was evaluated using dilatometry. The sintering temperature of the studied samples were also determined using heating microscopy. The effect of changing sintering temperature and of applying different isostatic pressures on the density and porosity of the compacts was investigated

Biosensor-based microRNA detection: techniques, design, performance, and challenges.

Science.gov (United States)

Johnson, Blake N; Mutharasan, Raj

2014-04-07

The current state of biosensor-based techniques for amplification-free microRNA (miRNA) detection is critically reviewed. Comparison with non-sensor and amplification-based molecular techniques (MTs), such as polymerase-based methods, is made in terms of transduction mechanism, associated protocol, and sensitivity. Challenges associated with miRNA hybridization thermodynamics which affect assay selectivity and amplification bias are briefly discussed. Electrochemical, electromechanical, and optical classes of miRNA biosensors are reviewed in terms of transduction mechanism, limit of detection (LOD), time-to-results (TTR), multiplexing potential, and measurement robustness. Current trends suggest that biosensor-based techniques (BTs) for miRNA assay will complement MTs due to the advantages of amplification-free detection, LOD being femtomolar (fM)-attomolar (aM), short TTR, multiplexing capability, and minimal sample preparation requirement. Areas of future importance in miRNA BT development are presented which include focus on achieving high measurement confidence and multiplexing capabilities.

Purification of Drug Loaded PLGA Nanoparticles Prepared by Emulsification Solvent Evaporation Using Stirred Cell Ultrafiltration Technique.

Science.gov (United States)

Paswan, Suresh K; Saini, T R

2017-12-01

The emulsifiers in an exceedingly higher level are used in the preparation of drug loaded polymeric nanoparticles prepared by emulsification solvent evaporation method. This creates great problem to the formulator due to their serious toxicities when it is to be administered by parenteral route. The final product is therefore required to be freed from the used surfactants by the conventional purification techniques which is a cumbersome job. The solvent resistant stirred cell ultrafiltration unit (Millipore) was used in this study using polyethersulfone ultrafiltration membrane (Biomax®) having pore size of NMWL 300 KDa as the membrane filter. The purification efficiency of this technique was compared with the conventional centrifugation technique. The flow rate of ultrafiltration was optimized for removal of surfactant (polyvinyl alcohol) impurities to the acceptable levels in 1-3.5 h from the nanoparticle dispersion of tamoxifen prepared by emulsification solvent evaporation method. The present investigations demonstrate the application of solvent resistant stirred cell ultrafiltration technique for removal of toxic impurities of surfactant (PVA) from the polymeric drug nanoparticles (tamoxifen) prepared by emulsification solvent evaporation method. This technique offers added benefit of producing more concentrated nanoparticles dispersion without causing significant particle size growth which is observed in other purification techniques, e.g., centrifugation and ultracentrifugation.

Recent trends in sorption-based sample preparation and liquid chromatography techniques for food analysis.

Science.gov (United States)

V Soares Maciel, Edvaldo; de Toffoli, Ana Lúcia; Lanças, Fernando Mauro

2018-04-20

The accelerated rising of the world's population increased the consumption of food, thus demanding more rigors in the control of residue and contaminants in food-based products marketed for human consumption. In view of the complexity of most food matrices, including fruits, vegetables, different types of meat, beverages, among others, a sample preparation step is important to provide more reliable results when combined with HPLC separations. An adequate sample preparation step before the chromatographic analysis is mandatory in obtaining higher precision and accuracy in order to improve the extraction of the target analytes, one of the priorities in analytical chemistry. The recent discovery of new materials such as ionic liquids, graphene-derived materials, molecularly imprinted polymers, restricted access media, magnetic nanoparticles, and carbonaceous nanomaterials, provided high sensitivity and selectivity results in an extensive variety of applications. These materials, as well as their several possible combinations, have been demonstrated to be highly appropriate for the extraction of different analytes in complex samples such as food products. The main characteristics and application of these new materials in food analysis will be presented and discussed in this paper. Another topic discussed in this review covers the main advantages and limitations of sample preparation microtechniques, as well as their off-line and on-line combination with HPLC for food analysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dye-sensitized solar cell based on optically transparent TiO{sub 2} nanocrystalline electrode prepared by atomized spray pyrolysis technique

Energy Technology Data Exchange (ETDEWEB)

Bandara, H.M.N., E-mail: hmnb@pdn.ac.l [Department of Chemistry, University of Peradeniya, Peradeniya (Sri Lanka); Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8011 (Japan); Rajapakse, R.M.G. [Department of Chemistry, University of Peradeniya, Peradeniya (Sri Lanka); Murakami, K. [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8011 (Japan); Kumara, G.R.R.A.; Anuradha Sepalage, G. [Department of Chemistry, University of Peradeniya, Peradeniya (Sri Lanka)

2011-10-30

Highlights: > Transparent TiO{sub 2} films were prepared by the atomized spray pyrolysis method. > These films contain 3-5 nm discrete particles, interconnected to give a crack-free thin film structure. > Dye-absorption of the TiO{sub 2} film is 2.16 times higher than those used in conventional DSCs. > Conversion efficiency of 8.2% can be achieved with 1000 W m{sup -2} irradiation. - Abstract: Preparation of crack-free thin films of interconnected and non-agglomerated TiO{sub 2} nanoparticles on electronically conducting fluorine doped tin oxide surfaces is instrumental in designing and developing transparent dye-sensitized solar cells (DSCs). A novel technique called 'Atomized Spray Pyrolysis' (ASP) has been designed and developed to achieve such perfectly transparent thin films. Optical transmittance of TiO{sub 2} films produced on FTO surface by this ASP method has been compared with those obtained by doctor-blading and by hand spray methods and found that the atomized spray pyrolysis technique give films with high transparency. Dye adsorption per gram of TiO{sub 2} is 2.16 times higher in the sample produced by the ASP method when compared to the film produced by the hand spray method and is 1.60 times higher than that produced by the doctor-blading method using a commercially available TiO{sub 2} nanocrystalline paste. SEM studies show the presence of interconnected discrete particles in the film produced by the ASP method. The fill factor (ff) remains almost constant for the cells with thickness from 6 {mu}m to 13 {mu}m but the highest photovoltage and photocurrent were found in {approx}10 {mu}m film based DSC which gave 8.2% conversion efficiency at AM 1.5 irradiation for cells of 0.25 cm{sup 2} active area.

The effect of swim-up and gradient sperm preparation techniques on deoxyribonucleic acid (DNA) fragmentation in subfertile patients.

Science.gov (United States)

Oguz, Yuksel; Guler, Ismail; Erdem, Ahmet; Mutlu, Mehmet Firat; Gumuslu, Seyhan; Oktem, Mesut; Bozkurt, Nuray; Erdem, Mehmet

2018-03-23

To compare the effect of two different sperm preparation techniques, including swim-up and gradient methods on sperm deoxyribonucleic acid (DNA) fragmentation status of semen samples from unexplained and mild male factor subfertile patients undergoing intrauterine insemination (IUI). A prospective randomized study was conducted in 65 subfertile patients, including 34 unexplained and 31 male factor infertility to compare basal and post-procedure DNA fragmentation rates in swim-up and gradient techniques. Sperm DNA fragmentation rates were evaluated by a sperm chromatin dispersion (SCD) test in two portions of each sample of semen that was prepared with either swim-up or gradient techniques. Sperm motility and morphology were also assessed based on WHO 2010 criteria. Swim-up but not gradient method yielded a statistically significant reduction in the DNA fragmented sperm rate after preparation as compared to basal rates, in the semen samples of both unexplained (41.85 ± 22.04 vs. 28.58 ± 21.93, p gradient) and mild male factor (46.61 ± 19.38 vs. 30.32 ± 18.20, p gradient) subgroups. Swim-up method significantly reduces sperm DNA fragmentation rates and may have some prognostic value on intrauterine insemination in patients with decreased sperm DNA integrity.

Brief review: Preparation techniques of biomass based activated carbon monolith electrode for supercapacitor applications

Science.gov (United States)

Taer, Erman; Taslim, Rika

2018-02-01

The synthesis of activated carbon monolith electrode made from a biomass material using the hydrolytic pressure or the pelletization technique of pre-carbonized materials is one of standard reported methods. Several steps such as pre-carbonization, milling, chemical activation, hydraulic press, carbonization, physical activation, polishing and washing need to be accomplished in the production of electrodes by this method. This is relatively a long process that need to be simplified. In this paper we present the standard method and proceed with the introduction to several alternative methods in the synthesis of activated carbon monolith electrodes. The alternative methods were emphasized on the selection of suitable biomass materials. All of carbon electrodes prepared by different methods will be analyzed for physical and electrochemical properties. The density, degree of crystallinity, surface morphology are examples for physical study and specific capacitance was an electrochemical properties that has been analysed. This alternative method has offered a specific capacitance in the range of 10 to 171 F/g.

Preparation of nanoparticles from acrylated palm oil microemulsion using radiation technique

International Nuclear Information System (INIS)

Rida Tajau; Wan Mohd Zin Wan Yunus; Khairul Zaman Mohd Dahlan; Mohd Hilmi Mahmood; Kamaruddin Hashim; Mohd Yusof Hamzah

2011-01-01

The use of microemulsion in the development of nanoparticle based on acrylated palm oil product is demonstrated. Acrylated palm oil microemulsions were prepared using ionic surfactant. Combination methods of emulsion polymerization and radiation crosslinking were applied to the microemulsion system for synthesizing nanoparticle. The ionizing radiation technique was introduced to generate a crosslinking reaction in the development of nanoparticle. The nanoparticle was evaluated in terms of particle diameter, surface charge, pH and conductance. Their image was captured using Transmission electron microscopy (TEM). Results show that the size, charge and shape of the particles are influenced by concentration of surfactants, monomer concentration, radiation dose and time of storage. The study showed a promising method to produced nanoparticle. This nano-sized product has the potential to be utilized as controlled-drug-release-carrier. (Author)

Preparation of a novel KCC-1/nylon 6 nanocomposite via electrospinning technique

Energy Technology Data Exchange (ETDEWEB)

Aghakhani, Ali [Material and Energy Research Center, Department of Semiconductors (Iran, Islamic Republic of); Kazemi, Ensiyeh; Kazemzad, Mahmood, E-mail: m-kazemzad@merc.ac.ir [Material and Energy Research Center, Department of Energy (Iran, Islamic Republic of)

2015-10-15

In this research, a novel nanofibrous composite of KCC-1/nylon 6 was prepared using electrospinning techniques. First, fibrous silica nanospheres (KCC-1) were synthesized via conventional polycondensation method with a new solvent system. The scanning electron microscopy (SEM) images showed a spongy spherical morphology with a uniform distribution of particle sizes and an average diameter of around 305 nm. Synthesized KCC-1 nanospheres are considered as mesoporous materials due to their high BET specific surface area of 576 m{sup 2} g{sup −1} and BJH average pore diameter of 3.28 nm. The KCC-1/nylon 6 composite was fabricated by preparing a dispersion of nanosilica (10–50 % w/w) in a solution of nylon 6 (15 % w/v) in formic acid. Upon applying a high voltage, the nonwoven electrospun KCC-1/nylon 6 composite nanofibers were obtained. The KCC-1 nanospheres were arranged in line along the nylon 6 fibers like rosary beads wrapped in the polymer. Based on the SEM images, we obtained a well-distributed nanocomposite even at higher silica content. The prepared KCC-1/nylon 6 composite showed 29–55 % higher BET specific surface area compared with pure nylon 6 nanofibers which makes it a good candidate to be used as a sorbent material for environmental or drug delivery applications.

Comparison of a new hydro-surgical technique to traditional methods for the preparation of full-thickness skin grafts from canine cadaveric skin and report of a single clinical case.

Science.gov (United States)

Townsend, F I; Ralphs, S C; Coronado, G; Sweet, D C; Ward, J; Bloch, C P

2012-01-01

To compare the hydro-surgical technique to traditional techniques for removal of subcutaneous tissue in the preparation of full-thickness skin grafts. Ex vivo experimental study and a single clinical case report. Four canine cadavers and a single clinical case. Four sections of skin were harvested from the lateral flank of recently euthanatized dogs. Traditional preparation methods used included both a blade or scissors technique, each of which were compared to the hydro-surgical technique individually. Preparation methods were compared based on length of time for removal of the subcutaneous tissue from the graft, histologic grading, and measurable thickness as compared to an untreated sample. The hydro-surgical technique had the shortest skin graft preparation time as compared to traditional techniques (p = 0.002). There was no significant difference in the histological grading or measurable subcutaneous thickness between skin specimens. The hydro-surgical technique provides a rapid, effective debridement of subcutaneous tissue in the preparation of full-thickness skin grafts. There were not any significant changes in histological grade and subcutaneous tissue remaining among all treatment types. Additionally the hydro-surgical technique was successfully used to prepare a full-thickness meshed free skin graft in the reconstruction of a traumatic medial tarsal wound in a dog.

Rational preparation of dibenzothiophene-imprinted polymers by surface imprinting technique combined with atom transfer radical polymerization

International Nuclear Information System (INIS)

Yang, Wenming; Liu, Lukuan; Zhou, Zhiping; Liu, Hong; Xie, Binze; Xu, Wanzhen

2013-01-01

A computational simulation method is introduced to simulate the dibenzothiophene-monomer pre-assembly system of molecular imprinted polymers. The interaction type and intensity between dibenzothiophene and monomer are discussed from the binding energy and spatial position distribution. The simulation and analysis results indicate that the amount of the function monomer is not the more the better in preparing molecular imprinted polymers. Based on the above results, a novel dibenzothiophene-imprinted polymers with the favorable specific adsorption effect was prepared by surface imprinting technique combined with atom transfer radical polymerization. This combined technologies are used for preparing a desulfurization adsorbent for the first time. Various measures were selected to characterize the structure and morphology of the prepared adsorbent. The characterization results show that the adsorbent has suitable features for further adsorption process. A series of static adsorption experiments were conducted to analyze its adsorption performance. The adsorption process follows Elovich model by the kinetic analysis and Sips equation by the isothermal analysis. The approach we described will provide another opportunity in the deep desulfurization field.

Sample preparation technique for transmission electron microscopy anodized Al-Li-SiC metal matrix composite

International Nuclear Information System (INIS)

Shahid, M.; Thomson, G.E.

1997-01-01

Along with improved mechanical properties, metal matrix composites (MMC) have a disadvantage of enhanced corrosion susceptibility in aggressive environments. Recent studies on corrosion behaviour of an Al-alloy 8090/SiC MMC, revealed considerably high corrosion rates of the MMC in near neutral solutions containing chloride ions. Anodizing is one of the potential surface treatment for the MMC to provide protective coating against corrosion. The surface and cross section of the anodized MMC can easily be observed using scanning electron microscope. The anodizing behaviour of the MMC can be understood further if the anodized cross section in examined under transmission electron microscope (TEM). However, it is relatively difficult to prepare small (3 mm diameter) electron transparent specimens of the MMC supporting an anodic film. In the present study a technique has been developed for preparing thin electron transparent specimens of the anodized MMC. This technique employed conventional ion beam thinning process but the preparation of small discs was a problem. A MMMC consisting of Al-alloy 8090 with 20 % (by weight) SiC particulate with an average size of 5 Mu m, was anodized and observed in TEM after preparing the samples using the above mentioned techniques. (author)

The preparation of ZnO based gas-sensing thin films by ink-jet printing method

International Nuclear Information System (INIS)

Shen Wenfeng; Zhao Yan; Zhang Caibei

2005-01-01

An ink-jet printing technique was applied to prepare ZnO based gas-sensing thin films. ZnO inks with appropriate viscosity and surface tension were prepared by sol-gel techniques, and printed onto substrates using a commercial printer. After the drying and heating treatment processes, continuous ZnO films were formed and studied by scanning electron microscopy, X-ray diffraction and by a home-made gas sensitivity measuring system. It was found that the morphology and electrical properties of the films changed significantly with the thickness of the films, which can be adjusted simply by printing on the film with increasing frequency. Highest resistance and sensitivity to acetone vapor were obtained when the film was prepared by printing only once on it. Different dopants with certain concentrations could be added into the films by printing with different dopant inks and printing frequency. All Pd, Ag, and ZrO 2 dopants increased both the resistivity and the sensitivity of the films (180 ppm acetone). This work showed that the ink-jet printing technique was a convenient and low cost method to prepare films with controlled film thickness and dopant concentration

Chitosan-Based Matrices Prepared by Gamma Irradiation for Tissue Regeneration: Structural Properties vs. Preparation Method.

Science.gov (United States)

Casimiro, Maria Helena; Lancastre, Joana J H; Rodrigues, Alexandra P; Gomes, Susana R; Rodrigues, Gabriela; Ferreira, Luís M

2017-02-01

In the last decade, new generations of biopolymer-based materials have attracted attention, aiming its application as scaffolds for tissue engineering. These engineered three-dimensional scaffolds are designed to improve or replace damaged, missing, or otherwise compromised tissues or organs. Despite the number of promising methods that can be used to generate 3D cell-instructive matrices, the innovative nature of the present work relies on the application of ionizing radiation technology to form and modify surfaces and matrices with advantage over more conventional technologies (room temperature reaction, absence of harmful initiators or solvents, high penetration through the bulk materials, etc.), and the possibility of preparation and sterilization in one single step. The current chapter summarizes the work done by the authors in the gamma radiation processing of biocompatible and biodegradable chitosan-based matrices for skin regeneration. Particular attention is given to the correlation between the different preparation conditions and the final polymeric matrices' properties. We therefore expect to demonstrate that instructive matrices produced and improved by radiation technology bring to the field of skin regenerative medicine a supplemental advantage over more conservative techniques.

Study On The Application Of Hydrogel Prepared By Radiation Technique For Fermentation Of Sawdust

International Nuclear Information System (INIS)

Le Thuy Trang; Nguyen Huynh Phuong Uyen; Vo Thu Ha; Le Quang Luan

2011-01-01

The super water-adsorption hydrogels was successfully preparation by radiation crosslinking CMC in paste condition and radiation grafting acrylic acid into starch. The hydrogel with 76.36% gel fraction and 91.13% swelling degree were obtained by irradiation of CMC 20% at 20 kGy, while the hydrogel with 65.3% gel fraction and 234 swelling degree was acrylic acid and starch at 4 kGy. The supplementation of hydrogels prepared by radiation technique showed a higher cellulose degradation effect of waste of cattle after fermenting 30 and 45 days. The optimum condition was determined by mixing 1% (w/w) dried hydrogel in 99% (w/w) waste of cattle. The fermented sawdust using hydrogel prepared by radiation technique showed a better effect on the growth of F1 Chinese cabbage (Brassica Pe-tsai Bailey L.). (author)

Sample preparation techniques in trace element analysis by X-ray emission spectroscopy

International Nuclear Information System (INIS)

Valkovic, V.

1983-11-01

The report, written under a research contract with the IAEA, contains a detailed presentation of the most difficult problem encountered in the trace element analysis by methods of the X-ray emission spectroscopy, namely the sample preparation techniques. The following items are covered. Sampling - with specific consideration of aerosols, water, soil, biological materials, petroleum and its products, storage of samples and their handling. Pretreatment of samples - preconcentration, ashing, solvent extraction, ion exchange and electrodeposition. Sample preparations for PIXE - analysis - backings, target uniformity and homogeneity, effects of irradiation, internal standards and specific examples of preparation (aqueous, biological, blood serum and solid samples). Sample preparations for radioactive sources or tube excitation - with specific examples (water, liquid and solid samples, soil, geological, plants and tissue samples). Finally, the problem of standards and reference materials, as well as that of interlaboratory comparisons, is discussed

Map Your Way to Speech Success! Employing Mind Mapping as a Speech Preparation Technique

Science.gov (United States)

Paxman, Christina G.

2011-01-01

Mind mapping has gained considerable credibility recently in corporations such as Boeing and Nabisco, as well as in the classroom in terms of preparing for examinations and preparing for speeches. A mind map is a graphic technique for organizing an individual's thoughts and other information. It harnesses the full range of cortical skills--word,…

The role of histological techniques for preparation of bone in studies of pl

International Nuclear Information System (INIS)

Alati, T.

1982-01-01

Techniques and methodologies for histological preparation of bone samples from plutonium-contaminated laboratory mice are described in the present report. These techniques have been set up within a research program on Pu-239 toxicity at low and very low activities. Pu-239 is a well-known alpha emitter with high relative biological effectiveness; when incorporated in mammalian organism it is also taken up by bone surfaces where osteosarcomas may be induced. This effect is very probably associated to the particular spatial relationships between the incorporated radionuclide and the target cells at risk. The research program actually in progress includes both the studies of late pathological effects, mainly in terms of bone tumor incidence and rate, and the quantitative description of the spatial relationships mentioned above. Whithin this framework, the techniques to described refer to the preparation of histological samples of demineralized bones for traditional histopathological analyses and of mineralized bones for studies of Pu-239 microdistributions by means of fission track analyses

Recent advances in sample preparation techniques and methods of sulfonamides detection - A review.

Science.gov (United States)

Dmitrienko, Stanislava G; Kochuk, Elena V; Apyari, Vladimir V; Tolmacheva, Veronika V; Zolotov, Yury A

2014-11-19

Sulfonamides (SAs) have been the most widely used antimicrobial drugs for more than 70 years, and their residues in foodstuffs and environmental samples pose serious health hazards. For this reason, sensitive and specific methods for the quantification of these compounds in numerous matrices have been developed. This review intends to provide an updated overview of the recent trends over the past five years in sample preparation techniques and methods for detecting SAs. Examples of the sample preparation techniques, including liquid-liquid and solid-phase extraction, dispersive liquid-liquid microextraction and QuEChERS, are given. Different methods of detecting the SAs present in food and feed and in environmental, pharmaceutical and biological samples are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Hydrating behavior of Mg-based nano-layers prepared by pulsed laser deposition

International Nuclear Information System (INIS)

Wioniewski, Z; Bystrzycki, J; Mroz, W; Jastrzabski, C

2009-01-01

The hydriding behavior of Mg with TiO 2 and Si nanolayers prepared by the pulsed laser deposition (PLD) was studied. The phase structure, chemical composition and hydriding properties of the obtained Mg-based nanolayers were investigated by the XRD, TEM, AFM, RS, SIMS and the volumetric Sievert method. It was shown that PLD is an excellent technique for producing the complex structures based on Mg. Both, the kinetic and destabilization topics were investigated in this paper.

Preparation of curcumin nanoparticle by using reinforcement ionic gelation technique

Science.gov (United States)

Suryani, Halid, Nur Hatidjah Awaliyah; Akib, Nur Illiyyin; Rahmanpiu, Mutmainnah, Nina

2017-05-01

Curcumin, a polyphenolic compound present in curcuma longa has a wide range of activities including anti-inflammatory properties. The potency of curcumin is limited by its poor oral bioavailability because of its poor solubility in aqueous. Various methods have been tried to solve the problem including its encapsulation into nanoparticle. The aim of this study is to develop curcumin nanoparticle by using reinforcement ionic gelation technique and to evaluate the stability of curcumin nanoparticles in gastrointestinal fluid. Curcumin nanoparticles were prepared by using reinforcement ionic gelation technique with different concentrations of chitosan, trypolyphosphate, natrium alginate and calcium chloride. Curcumin nanoparticles were then characterized including particle size and zeta potential by using particle size analyzer and morphology using a transmission electron microscope, entrapment efficiency using UV-Vis Spectrophotometer and chemical structure analysis by Infra Red Spectrophotometer (FTIR). Furthermore, the stability of curcumin nanoparticles were evaluated on artificial gastric fluid and artificial intestinal fluids by measuring the amount of curcumin released in the medium at a time interval. The result revealed that curcumin nanoparticles can be prepared by reinforcement ionic gelation technique, the entrapment efficiency of curcumin nanoparticles were from 86.08 to 91.41%. The average of particle size was 272.9 nm and zeta potential was 12.05 mV. The morphology examination showed that the curcumin nanoparticles have spherical shape. The stability evaluation of curcumin nanoparticles showed that the nanoparticles were stable on artificial gastric fluid and artificial intestinal fluid. This result indicates that curcumin nanoparticles have the potential to be developed for oral delivery.

An Overview on Base Real-Time Hard Shadow Techniques in Virtual Environments

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Mohd Shahrizal Sunar

2012-03-01

Full Text Available Shadows are elegant to create a realistic scene in virtual environments variety type of shadow techniques encourage us to prepare an overview on all base shadow techniques. Non real-time and real-time techniques are big subdivision of shadow generation. In non real-time techniques ray tracing, ray casting and radiosity are well known and are described deeply. Radiosity is implemented to create very realistic shadow on non real-time scene. Although traditional radiosity algorithm is difficult to implement, we have proposed a simple one. The proposed pseudo code is easier to understand and implement. Ray tracing is used to prevent of collision of movement objects. Projection shadow, shadow volume and shadow mapping are used to create real-time shadow in virtual environments. We have used projection shadow for some objects are static and have shadow on flat surface. Shadow volume is used to create accurate shadow with sharp outline. Shadow mapping that is the base of most recently techniques is reconstructed. The reconstruct algorithm gives some new idea to propose another algorithm based on shadow mapping.

Raman and IR spectroscopic structural characterization of LiAlO2 powders prepared using a liquid mix technique

International Nuclear Information System (INIS)

Cornilsen, B.C.; Loyselle, P.L.; Saporta, J.D.

1990-01-01

γ-LiAlO 2 and β-LiAlO 2 have been characterized using Raman and infrared spectroscopy. Powders have been prepared using two different preparation techniques: a solution method known as the liquid mix technique (LMT) and the traditional ceramic method. The authors find that the LMT allows direct production of single phase γ-LiAlO 2 at 600 degrees C, below that found using other preparation methods. Furthermore, this solution technique appears to avoid formation of the β-LiAlO 2 intermediate phase. At lower temperatures, the LMT product is a disordered precursor of γ- LiAlO 2

Peptide-Loaded Solid Lipid Nanoparticles Prepared through Coacervation Technique

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Marina Gallarate

2011-01-01

Full Text Available Stearic acid solid lipid nanoparticles were prepared according to a new technique, called coacervation. The main goal of this experimental work was the entrapment of peptide drugs into SLN, which is a difficult task, since their chemical characteristics (molecular weight, hydrophilicity, and stability hamper peptide-containing formulations. Insulin and leuprolide, chosen as model peptide drugs, were encapsulated within nanoparticles after hydrophobic ion pairing with anionic surfactants. Peptide integrity was maintained after encapsulation, and nanoparticles can act in vitro as a sustained release system for peptide.

Hamstrings tendon graft preparation for anterior cruciate ligament reconstruction using the WhipKnotTM soft tissue cinch technique.

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Amin Masoumiganjgah

2012-04-01

Full Text Available BackgroundAppropriate graft tension and secure graft incorporation inbone tunnels are essential for successful anterior cruciateligament (ACL reconstruction using hamstrings tendonautografts. The WhipKnot™ soft tissue cinch, introduced bySmith and Nephew in 2004, is an alternative option to thecommonly used whipstitch technique during preparation ofthe hamstring autograft in ACL reconstruction.AimsTo investigate the effectiveness of the WhipKnot™ softtissue cinch and technique during the preparation of thetendon graft for ACL reconstruction.MethodA total of 33 ACL reconstruction operations performedbetween February 2011 and December 2011 were includedin this study. These were performed by a single seniorsurgeon who used the Whipknot™ technique for thepreparation of each graft. Four were used for eachoperation; two for each end of the harvested hamstringstendons, including semitendinosus and gracilis tendonsrespectively.ResultsIn total, 132 WhipKnots were used during the kneeoperations. Use of the WhipKnot™ technique resulted insuccessful graft preparations, tensioning and effective graftplacement in the tibial and femoral tunnels in almost allinstances. Only one case of WhipKnot™ failure (slippagewas recorded.ConclusionThese results indicate that the Whipknot™ technique is asafe, reliable and practical option for the preparation of thehamstrings autografts.

The taper of cast post preparation measured using innovative image processing technique

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Al Hyiasat Ahmad S

2010-08-01

Full Text Available Abstract Background No documentation in the literature about taper of cast posts. This study was conducted to measure the degree of cast posts taper, and to evaluate its suitability based on the anatomy aspects of the common candidate teeth for post reconstruction. Methods Working casts for cast posts, prepared using Gates Glidden drills, were collected. Impressions of post spaces were made using polyvinyl siloxan putty/wash technique. Digital camera with a 10' high quality lens was used for capturing two digital images for each impression; one in the Facio-Lingual (FL and the other in the Mesio-Distal (MD directions. Automated image processing program was developed to measure the degree of canal taper. Data were analyzed using Statistical Package for Social Sciences software and One way Analysis of Variance. Results Eighty four dies for cast posts were collected: 16 for each maxillary anterior teeth subgroup, and 18 for each maxillary and mandibular premolar subgroup. Mean of total taper for all preparations was 10.7 degree. There were no statistical differences among the total taper of all groups (P = .256 or between the MD and FL taper for each subgroup. Mean FL taper for the maxillary first premolars was lower significantly (P = .003 than the maxillary FL taper of the second premolars. FL taper was higher than the MD taper in all teeth except the maxillary first premolars. Conclusions Taper produced did not reflect the differences among the anatomy of teeth. While this technique deemed satisfactory in the maxillary anterior teeth, the same could not be said for the maxillary first premolars. Careful attention to the root anatomy is mandatory.

Preparation of UO2 dense spherical particles by sol-gel technique

International Nuclear Information System (INIS)

Urbanek, V.; Dolezal, J.

1977-01-01

The results of the basic research and development of processes of preparation of dense UO 2 spherical particles by sol-gel technique are presented. Attention was paid to the study of chemistry of internal gelation step in the uranylnitrate-urea-hexamethylentetramine system. The existence regions of several stable gels with different properties were established in connection with variable ratio of basic gel's components and the appropriate ''Phase diagrams'' were drawn. From these diagrams, two of the most interesting types of uranyl gels were chosen for the subsequent thermal processing which included drying, reduction and sintering. The detailed studies of each step of the whole process enabled preparation of UO 2 dense spheres with well defined microstructure

Ceria/silicon carbide core–shell materials prepared by miniemulsion technique

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Lars Borchardt

2011-09-01

Full Text Available For the first time we present the synthesis of CeO2/Si(OC core–shell particles prepared by the miniemulsion technique. The Si(OC core was obtained by means of a polycarbosilane precursor (SMP10, which was subsequently functionalized with ceria and pyrolyzed to the ceramic. The size of these particles could easily be adjusted by varying the surfactants and the surfactant concentration, or by the addition of comonomers. Hence particle sizes ranged from 100 to 1000 nm, tunable by the preparation conditions. All materials were characterized by photon cross correlation spectroscopy, scanning electron microscopy and elemental mapping investigations. Furthermore, first catalytic tests were carried out by temperature programmed oxidation (TPO of methane, and the activity of this material in lowering the onset temperature of methane combustion by 262 K was documented.

The associations among family meal frequency, food preparation frequency, self-efficacy for cooking, and food preparation techniques in children and adolescents.

Science.gov (United States)

Woodruff, Sarah J; Kirby, Ashley R

2013-01-01

The purpose of this study was to describe family dinner frequency (FDF) by food preparation frequency (prep), self-efficacy for cooking (SE), and food preparation techniques (techniques) among a small sample in southwestern Ontario, Canada. A cross-sectional survey was administered under the supervision of the research team. After-school programs, sports programs, and 1 elementary school. The sample included 145 participants (41% boys, 59% girls) in grades 4-8. Demographics, prep, SE, techniques, FDF, and family meal attitudes and behaviors. Exploratory 1-way ANOVA and chi-square analyses were used. An ordinal regression analysis was used to determine the associations between FDF with descriptor variables (sex, grade, and ethnicity) and prep, SE, techniques, FDF, and family meal attitudes and behaviors (P < .05). Approximately 59% reported family dinners on 6 or 7 days per week. Half of participants were involved with prep 1-6 times per week. Mean SE was 25.3 (scale 1-32), and girls performed more techniques than boys (P = .02). Participants with greater SE (odds ratio = 1.15) and higher family meal attitudes and behaviors (odds ratio = 1.15) were more likely to have a higher FDF. Future health promotion strategies for family meals should aim at increasing children's and adolescents' SE. Copyright © 2013 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

Magnetic properties of iron nanoparticles prepared by exploding wire technique

OpenAIRE

Alqudami, Abdullah; Annapoorni, S.; Lamba, Subhalakshmi; Kothari, P C; Kotnala, R K

2006-01-01

Nanoparticles of iron were prepared in distilled water using very thin iron wires and sheets, by the electro-exploding wire technique. Transmission electron microscopy reveals the size of the nanoparticles to be in the range 10 to 50 nm. However, particles of different sizes can be segregated by using ultrahigh centrifuge. X-ray diffraction studies confirm the presence of the cubic phase of iron. These iron nanoparticles were found to exhibit fluorescence in the visible region in contrast to ...

Recent Trends in Microextraction Techniques Employed in Analytical and Bioanalytical Sample Preparation

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Abuzar Kabir

2017-12-01

Full Text Available Sample preparation has been recognized as a major step in the chemical analysis workflow. As such, substantial efforts have been made in recent years to simplify the overall sample preparation process. Major focusses of these efforts have included miniaturization of the extraction device; minimizing/eliminating toxic and hazardous organic solvent consumption; eliminating sample pre-treatment and post-treatment steps; reducing the sample volume requirement; reducing extraction equilibrium time, maximizing extraction efficiency etc. All these improved attributes are congruent with the Green Analytical Chemistry (GAC principles. Classical sample preparation techniques such as solid phase extraction (SPE and liquid-liquid extraction (LLE are being rapidly replaced with emerging miniaturized and environmentally friendly techniques such as Solid Phase Micro Extraction (SPME, Stir bar Sorptive Extraction (SBSE, Micro Extraction by Packed Sorbent (MEPS, Fabric Phase Sorptive Extraction (FPSE, and Dispersive Liquid-Liquid Micro Extraction (DLLME. In addition to the development of many new generic extraction sorbents in recent years, a large number of molecularly imprinted polymers (MIPs created using different template molecules have also enriched the large cache of microextraction sorbents. Application of nanoparticles as high-performance extraction sorbents has undoubtedly elevated the extraction efficiency and method sensitivity of modern chromatographic analyses to a new level. Combining magnetic nanoparticles with many microextraction sorbents has opened up new possibilities to extract target analytes from sample matrices containing high volumes of matrix interferents. The aim of the current review is to critically audit the progress of microextraction techniques in recent years, which has indisputably transformed the analytical chemistry practices, from biological and therapeutic drug monitoring to the environmental field; from foods to phyto

Observation particle morphology of colloidal system by conventional SEM with an improved specimen preparation technique.

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Xu, Jing; Hou, Zhaosheng; Yuan, Xiaojiao; Guo, Hong

2011-08-01

On the basis of our previous report that polymer emulsion with different viscosity can be investigated by conventional scanning electron microscopy (SEM), we have developed an improved specimen preparation technique for obtaining particle morphology and size of colloidal silver, collagen, glutin, and polymer microspheres. In this study, we expect to provide a means for charactering the three-dimensional surface microstructure of colloidal particles. Dilution of the samples with appropriate volatile solvent like ethanol is effective for SEM specimen preparation. At a proper ratio between sample and ethanol, the colloidal particles are dispersed uniformly in ethanol and then deposited evenly on the substrate. Different drying methods are studied to search a proper drying condition, in which the small molecule solvent is removed without destroying the natural particle morphology. And the effects of ethanol in the specimen preparation process are described by analyzing the physicochemical properties of ethanol. The specimen preparation technique is simple and can be achieved in common laboratory for charactering the particle morphology of colloidal system. Copyright © 2010 Wiley-Liss, Inc.

Development and application of a dry ultramicrotomy technique for the preparation of galvanneal sheet coatings.

Science.gov (United States)

Barreto, M P; Veillette, R; L'Espérance, G

1995-07-01

The formability of galvanneal steel sheets used in the automotive industry is influenced by the presence and distribution of brittle and difficult to distinguish Zn-Fe intermetallics in the coating. Characterization of these intermetallics requires a high spatial resolution technique such as analytical transmission electron microscopy (ATEM). Sample preparation by ion milling is impossible due to iron redeposition, and traditional ultramicrotomy using water affects the coating chemistry. A technique based on dry ultramicrotomy has therefore been developed. To optimize the technique, different parameters (knife angle, cutting medium, thickness setting on the ultramicrotome, cutting speed) have been investigated for the preparation of galvanneal coatings and pure A1 sections. Results show that dry cutting does not affect the coating chemistry but shortens the life of the knife. Knife quality (cleanliness, sharpness and absence of defects) is a major factor to obtain good dry sections. The best results for the more ductile pure A1 are obtained with a 35 degrees knife whilst for the harder galvanneal coating it is recommended to use a 55 degrees knife. These results suggest that the sectioning mechanism for the harder material involves more a cleavage-fracture mechanism whilst a greater amount of shear is involved when sectioning relatively ductile A1. The optimum parameters for sectioning galvanneal coatings are established and results obtained by parallel electron energy loss spectrum imaging and energy dispersive X-ray spectrometry in the TEM are given. This study shows that with a good control of all the sectioning parameters it is possible to obtain good sections repeatedly and rapidly.

Formation and characterization of vitreous materials prepared by the sol-gel technique

International Nuclear Information System (INIS)

Martinez, J.R.; Ruiz, J.F.; Cruz M, J.A. de la; Villasenor G, P.

1999-01-01

A full process of preparation and characterization of silica gel, which can be implemented in a experimental course for undergraduate laboratories is presented. Samples of silica gel and sol-gel derived SiO 2 films on glass substrates were fabricated and characterized using atomic force microscopy, Raman and Infrared absorption techniques. Raman and Infrared spectroscopy were used to analyze the local structure. The microstructure characteristics of the films, fabricated by dip-coating, were monitored using atomic force microscopy. The samples were prepared from alcoholic solutions of tetraethylortosilicate (TEOS) keeping the H 2 O/TEOS and Et-OH/TEOS molar ratios constant and equal to 11.66 and 4 respectively. (Author)

Web-based tailored intervention for preparation of parents and children for outpatient surgery (WebTIPS): development.

Science.gov (United States)

Kain, Zeev N; Fortier, Michelle A; Chorney, Jill MacLaren; Mayes, Linda

2015-04-01

As a result of cost-containment efforts, preparation programs for outpatient surgery are currently not available to the majority of children and parents. The recent dramatic growth in the Internet presents a unique opportunity to transform how children and their parents are prepared for surgery. In this article, we describe the development of a Web-based Tailored Intervention for Preparation of parents and children undergoing Surgery (WebTIPS). A multidisciplinary taskforce agreed that a Web-based tailored intervention consisting of intake, matrix, and output modules was the preferred approach. Next, the content of the various intake variables, the matrix logic, and the output content was developed. The output product has a parent component and a child component and is described in http://surgerywebtips.com/about.php. The child component makes use of preparation strategies such as information provision, modeling, play, and coping skills training. The parent component of WebTIPS includes strategies such as information provision, coping skills training, and relaxation and distraction techniques. A reputable animation and Web design company developed a secured Web-based product based on the above description. In this article, we describe the development of a Web-based tailored preoperative preparation program that can be accessed by children and parents multiple times before and after surgery. A follow-up article in this issue of Anesthesia & Analgesia describes formative evaluation and preliminary efficacy testing of this Web-based tailored preoperative preparation program.

Evaluation of specimen preparation techniques for micro-PIXE localisation of elements in hyperaccumulating plants

International Nuclear Information System (INIS)

Kachenko, Anthony G.; Siegele, Rainer; Bhatia, Naveen P.; Singh, Balwant; Ionescu, Mihail

2008-01-01

Hybanthus floribundus subsp. floribundus, a rare Australian Ni-hyperaccumulating shrub and Pityrogramma calomelanos var. austroamericana, an Australian naturalized As-hyperaccumulating fern are promising species for use in phytoremediation of contaminated sites. Micro-proton-induced X-ray emission (μ-PIXE) spectroscopy was used to map the elemental distribution of the accumulated metal(loid)s, Ca and K in leaf or pinnule tissues of the two plant species. Samples were prepared by two contrasting specimen preparation techniques: freeze-substitution in tetrahydrofuran (THF) and freeze-drying. The specimens were analysed to compare the suitability of each technique in preserving (i) the spatial elemental distribution and (ii) the tissue structure of the specimens. Further, the μ-PIXE results were compared with concentration of elements in the bulk tissue obtained by ICP-AES analysis. In H. floribundus subsp. floribundus, μ-PIXE analysis revealed Ni, Ca and K concentrations in freeze-dried leaf tissues were at par with bulk tissue concentrations. Elemental distribution maps illustrated that Ni was preferentially localised in the adaxial epidermal tissues (1% DW) and least concentration was found in spongy mesophyll tissues (0.53% DW). Conversely, elemental distribution maps of THF freeze-substituted tissues indicated significantly lower Ni, Ca and K concentrations than freeze-dried specimens and bulk tissue concentrations. Moreover, Ni concentrations were uniform across the whole specimen and no localisation was observed. In P. calomelanos var. austroamericana freeze-dried pinnule tissues, μ-PIXE revealed statistically similar As, Ca and K concentrations as compared to bulk tissue concentrations. Elemental distribution maps showed that As localisation was relatively uniform across the whole specimen. Once again, THF freeze-substituted tissues revealed a significant loss of As compared to freeze-dried specimens and the concentrations obtained by bulk tissue analysis

Protein-Based Nanoparticle Preparation via Nanoprecipitation Method

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Mohamad Tarhini

2018-03-01

Full Text Available Nanoparticles are nowadays largely investigated in the field of drug delivery. Among nanoparticles, protein-based particles are of paramount importance since they are natural, biodegradable, biocompatible, and nontoxic. There are several methods to prepare proteins containing nanoparticles, but only a few studies have been dedicated to the preparation of protein- based nanoparticles. Then, the aim of this work was to report on the preparation of bovine serum albumin (BSA-based nanoparticles using a well-defined nanoprecipitation process. Special attention has been dedicated to a systematic study in order to understand separately the effect of each operating parameter of the method (such as protein concentration, solvent/non-solvent volume ratio, non-solvent injection rate, ionic strength of the buffer solution, pH, and cross-linking on the colloidal properties of the obtained nanoparticles. In addition, the mixing processes (batch or drop-wise were also investigated. Using a well-defined formulation, submicron protein-based nanoparticles have been obtained. All prepared particles have been characterized in terms of size, size distribution, morphology, and electrokinetic properties. In addition, the stability of nanoparticles was investigated using Ultraviolet (UV scan and electrophoresis, and the optimal conditions for preparing BSA nanoparticles by the nanoprecipitation method were concluded.

Quantification of normal vaginal constituents using a new wet preparation technique.

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Fowler, R Stuart

2012-10-01

This study aimed to evaluate a new method for preparing vaginal wet preparations to enable quantification of cells and lactobacilli. The current nonstandardized technique allows for a variable amount of vaginal fluid collected, diluted by a variable amount of saline/KOH, and no quantification of constituents. The vaginal fluids from 100 randomly selected women without vulvovaginitis symptoms presenting to the author's practice at Mayo Clinic underwent analysis by the quantification technique. Women were excluded if they were younger than 18 years, had antibiotics within the past 2 months, currently on their period, had placed anything in the vagina for the past 24 hours, used Depo-Provera, or were lactating. All the wet preparations were made by mixing the natural vaginal fluids with 3 mL of sterile normal saline. Spinal diluting fluid was added to the saline preparation. The saline and KOH mixtures were injected into separate wells of KOVA Glasstic Grid Slide and analyzed with a phase-contrast microscope at 40× and 60×. The concentration of leukocytes, lactobacilli, and squamous cells and the degree of maturation of the majority (>50%) of squamous cells were assessed, and it was determined whether there was excessive non-lactobacilli bacteria (EB) as evident by clumps of bacteria in the background fluid and speckling on the squamous cells. The 3 most common patterns to occur were as follows: First, 51% (95% confidence interval [CI] = 41%-60%) of the total specimens had abundant lactobacilli, no leukocytes, more than 50% fully maturated squamous cells, and no EB. Second, 22% (95% CI = 14%-32%) of the total specimens had low lactobacilli counts, no leukocytes, more than 50% undermaturated squamous cells, and no EB. Third, 12% (95% CI = 6%-20%) of the total specimens had abundant lactobacilli, leukocytes, more than 50% fully maturated squamous cells, and no EB. It is imperative to be able to objectively quantify normal vaginal secretion constituents so that (1) the

Evaluating different closed loop graft preparation technique for tibial suspensory fixation in ACL reconstruction using TightRope™

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Takahisa Sasho

2018-04-01

Full Text Available In most anterior cruciate ligament (ACL reconstructions, grafts are fixed to the femoral side first followed by the tibial side. Various techniques have been reported to achieve optimal tension on the grafts, but once the grafts are fixed it is difficult to adjust graft tension further. To enable post fixation tension control we have invented a new graft configuration using an adjustable loop-device (TightRopeTM, Arthrex, FL, USA on the tibial side. In this paper, biomechanical properties of this configuration using soft tissue were examined in terms of graft diameter and various suture techniques (referred to as base suture to make a closed circle to support TightRopeTM.Two experiments were conducted under different conditions. In each experiment, cyclic load, followed by a pull-to-failure load, was applied to the grafts and elongation and failure mode were recorded. (1 To evaluate the effects of diameter, 5.0 or 6.0 mm grafts were prepared by a single locking loop stitch as the base suture (SLL5, SLL6. (2 To evaluate different base sutures, 5.0 mm tendons were used, and grafts were prepared using five kinds of base sutures (SLL, ZLL: zigzag locking loop, DZLL: double zigzag locking loop, DK: double Krackow, DK w/o TR: double Krackow without TightRopeTM. In the first experiment, tearing was observed in 2 of 6 cases in the SLL5 test group, whereas no tearing was observed with SLL6. In the second experiment, no tearing was observed with DZLL or DK. Elongation was smaller in these two groups compared to the other groups. Mechanical strength decreases with a smaller graft diameter. Biomechanical properties differed with different base sutures and, among them, the double-zigzag-suture stitch and double Krackow provided less elongation and higher ultimate load in this graft configuration.

Craniospinal radiotherapy in children: Electron- or photon-based technique of spinal irradiation

International Nuclear Information System (INIS)

Chojnacka, M.; Skowronska-Gardas, A.; Pedziwiatr, K.; Morawska-Kaczynska, M.; Zygmuntowicz-Pietka, A.; Semaniak, A.

2010-01-01

Background: The prone position and electron-based technique for craniospinal irradiation (CSI) have been standard in our department for many years. But this immobilization is difficult for the anaesthesiologist to gain airway access. The increasing number of children treated under anaesthesia led us to reconsider our technique. Aim: The purpose of this study is to report our new photon-based technique for CSI which could be applied in both the supine and the prone position and to compare this technique with our electron-based technique. Materials and methods: Between November 2007 and May 2008, 11 children with brain tumours were treated in the prone position with CSI. For 9 patients two treatment plans were created: the first one using photons and the second one using electron beams for spinal irradiation. We prepared seven 3D-conformal photon plans and four forward planned segmented field plans. We compared 20 treatment plans in terms of target dose homogeneity and sparing of organs at risk. Results: In segmented field plans better dose homogeneity in the thecal sac volume was achieved than in electron-based plans. Regarding doses in organs at risk, in photon-based plans we obtained a lower dose in the thyroid but a higher one in the heart and liver. Conclusions: Our technique can be applied in both the supine and prone position and it seems to be more feasible and precise than the electron technique. However, more homogeneous target coverage and higher precision of dose delivery for photons are obtained at the cost of slightly higher doses to the heart and liver. (authors)

Silver ion chromatography for peak resolution enhancement: Application to the preparative separation of two sesquiterpenes using online heart-cutting LC-LC technique.

Science.gov (United States)

Yang, Yang; Zhang, Yongmin; Wei, Chong; Li, Jing; Sun, Wenji

2018-09-01

Silver ion chromatography, utilizing columns packed with silver ions bonded to silica gel, has proved to be an invaluable technique for the analysis of some positional isomers. In this work, silver ion chromatography by combination with online heart-cutting LC-LC technique for the preparative separation of two sesquiterpenes positional isomers from a natural product was investigated. On the basis of the evaluation that silver ion content impacts on the separation, the laboratory-made silver ion columns, utilizing silica gel impregnated with 15% silver nitrate as column packing materials, were used for peak resolution improvement of these two isomers and the preparative separation of them in heart-cutting LC-LC. The relationship among the maximal sample load, flow rate and peak resolution in the silver ion column were optimized, and the performance of the silver ion column was compared with conventional C 18 column and silica gel column. Based on the developed chromatographic conditions, online heart-cutting LC-LC chromatographic separation system in combination with a silica gel column and a silver ion column that was applied to preparative separation of these two isomers from a traditional Chinese medicine, Inula racemosa Hook.f., was established. The results showed that the online heart-cutting LC-LC technique by combination of a silica gel column and a silver ion column for the preparative separation of these two positional isomers from this natural plant was superior to the preparative separation performed on a single-column system with C 18 column or silica gel column. Copyright © 2018 Elsevier B.V. All rights reserved.

Virtual fragment preparation for computational fragment-based drug design.

Science.gov (United States)

Ludington, Jennifer L

2015-01-01

Fragment-based drug design (FBDD) has become an important component of the drug discovery process. The use of fragments can accelerate both the search for a hit molecule and the development of that hit into a lead molecule for clinical testing. In addition to experimental methodologies for FBDD such as NMR and X-ray Crystallography screens, computational techniques are playing an increasingly important role. The success of the computational simulations is due in large part to how the database of virtual fragments is prepared. In order to prepare the fragments appropriately it is necessary to understand how FBDD differs from other approaches and the issues inherent in building up molecules from smaller fragment pieces. The ultimate goal of these calculations is to link two or more simulated fragments into a molecule that has an experimental binding affinity consistent with the additive predicted binding affinities of the virtual fragments. Computationally predicting binding affinities is a complex process, with many opportunities for introducing error. Therefore, care should be taken with the fragment preparation procedure to avoid introducing additional inaccuracies.This chapter is focused on the preparation process used to create a virtual fragment database. Several key issues of fragment preparation which affect the accuracy of binding affinity predictions are discussed. The first issue is the selection of the two-dimensional atomic structure of the virtual fragment. Although the particular usage of the fragment can affect this choice (i.e., whether the fragment will be used for calibration, binding site characterization, hit identification, or lead optimization), general factors such as synthetic accessibility, size, and flexibility are major considerations in selecting the 2D structure. Other aspects of preparing the virtual fragments for simulation are the generation of three-dimensional conformations and the assignment of the associated atomic point charges.

Identifying content-based and relational techniques to change behaviour in motivational interviewing.

Science.gov (United States)

Hardcastle, Sarah J; Fortier, Michelle; Blake, Nicola; Hagger, Martin S

2017-03-01

Motivational interviewing (MI) is a complex intervention comprising multiple techniques aimed at changing health-related motivation and behaviour. However, MI techniques have not been systematically isolated and classified. This study aimed to identify the techniques unique to MI, classify them as content-related or relational, and evaluate the extent to which they overlap with techniques from the behaviour change technique taxonomy version 1 [BCTTv1; Michie, S., Richardson, M., Johnston, M., Abraham, C., Francis, J., Hardeman, W., … Wood, C. E. (2013). The behavior change technique taxonomy (v1) of 93 hierarchically clustered techniques: Building an international consensus for the reporting of behavior change interventions. Annals of Behavioral Medicine, 46, 81-95]. Behaviour change experts (n = 3) content-analysed MI techniques based on Miller and Rollnick's [(2013). Motivational interviewing: Preparing people for change (3rd ed.). New York: Guildford Press] conceptualisation. Each technique was then coded for independence and uniqueness by independent experts (n = 10). The experts also compared each MI technique to those from the BCTTv1. Experts identified 38 distinct MI techniques with high agreement on clarity, uniqueness, preciseness, and distinctiveness ratings. Of the identified techniques, 16 were classified as relational techniques. The remaining 22 techniques were classified as content based. Sixteen of the MI techniques were identified as having substantial overlap with techniques from the BCTTv1. The isolation and classification of MI techniques will provide researchers with the necessary tools to clearly specify MI interventions and test the main and interactive effects of the techniques on health behaviour. The distinction between relational and content-based techniques within MI is also an important advance, recognising that changes in motivation and behaviour in MI is a function of both intervention content and the interpersonal style

Even an old technique is suitable in the molecular world of science: the everted sac preparation turns 60 years old.

Science.gov (United States)

Hamilton, Kirk L

2014-04-15

An old proverb states "necessity is the mother of invention." This certainly holds true in science as one pursues research questions. Experimental techniques have evolved as scientists have asked more specific research questions. Indeed, techniques such as the Ussing chamber, the perfused renal tubule preparation, patch-clamp, polymerase chain reaction, and site-directed mutagenesis have been developed over the past 60 years. However, sometimes, simple techniques may be useful and still very informative, and this certainly applies to intestinal physiology. Indeed, Gerald Wiseman and Thomas Hastings Wilson described the intestinal everted sac preparation some 60 years ago. Since then, this technique has been used for numerous research purposes including determining ion, amino acid, water and solute transport across the intestinal epithelium; and drug metabolism, absorption, and interactions in pharmaceutical/pharmacological research and even in education. This article provides a historical review of the development of the in vitro intestinal preparation that led to the everted sac preparation and its use in science.

Adapted preparation technique for screw-type implants: explorative in vitro pilot study in a porcine bone model.

Science.gov (United States)

Beer, Andreas; Gahleitner, André; Holm, Anders; Birkfellner, Wolfgang; Homolka, Peter

2007-02-01

The aim of this study was to quantify the effect of adapted preparation on the insertion torque of self-tapping implants in cancellous bone. In adapted preparation, bone condensation - and thus, insertion torque - is controlled by changing the diameter of the drilling. After preparation of cancellous porcine vertebral bone with drills of 2.85, 3, 3.15 or 3.35 mm final diameters, Brånemark sytem Mk III implants (3.75 x 11.5 mm) were inserted in 141 sites. During implantation, the insertion torque was recorded. Prior to implant insertion, bone mineralization (bone mineral density (BMD)) was measured with dental quantative computed tomography. The BMD values measured at the implant position were correlated with insertion torque for varying bone condensation. Based on the average torque recorded during implant insertion into the pre-drilled canals with a diameter of 3 mm, torque increased by approximately 17% on reducing the diameter of the drill by 5% (to 2.85 mm). On increasing the diameter of the osteotomy to 3.15 mm (5%) or 3.35 mm (12%), torque values decreased by approximately 21% and 50%, respectively. The results demonstrate a correlation between primary stability (average insertion torque) and the diameter of the implant bed on using a screw-shaped implant. Thus, using an individualized bone mineralization-dependent drilling technique, optimized torque values could be achieved in all tested bone qualities with BMDs ranging from 330 to 500 mg/cm(3). The results indicate that using a bone-dependent drilling technique, higher torque values can also be achieved in poor bone using an individualized drilling resulting in higher bone condensation. As immediate function is dependent on primary stability (high insertion torque), this indicates that primary stability can be increased using a modified drilling technique in lesser mineralized bone.

Experimental Analysis of Temperature Differences During Implant Site Preparation: Continuous Drilling Technique Versus Intermittent Drilling Technique.

Science.gov (United States)

Di Fiore, Adolfo; Sivolella, Stefano; Stocco, Elena; Favero, Vittorio; Stellini, Edoardo

2018-02-01

Implant site preparation through drilling procedures may cause bone thermonecrosis. The aim of this in vitro study was to evaluate, using a thermal probe, overheating at implant sites during osteotomies through 2 different drilling methods (continuous drilling technique versus intermittent drilling technique) using irrigation at different temperatures. Five implant sites 13 mm in length were performed on 16 blocks (fresh bovine ribs), for a total of 80 implant sites. The PT-100 thermal probe was positioned 5 mm from each site. Two physiological refrigerant solutions were used: one at 23.7°C and one at 6.0°C. Four experimental groups were considered: group A (continuous drilling with physiological solution at 23.7°C), group B (intermittent drilling with physiological solution at 23.7°C), group C (continuous drilling with physiological solution at 6.0°C), and group D (intermittent drilling with physiological solution at 6.0°C). The Wilcoxon rank-sum test (2-tailed) was used to compare groups. While there was no difference between group A and group B (W = 86; P = .45), statistically significant differences were observed between experimental groups A and C (W = 0; P =.0001), B and D (W = 45; P =.0005), and C and D (W = 41; P = .003). Implant site preparation did not affect the overheating of the bone. Statistically significant differences were found with the refrigerant solutions. Using both irrigating solutions, bone temperature did not exceed 47°C.

Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques.

Science.gov (United States)

Bhattarai, Jay K; Neupane, Dharmendra; Nepal, Bishal; Mikhaylov, Vasilii; Demchenko, Alexei V; Stine, Keith J

2018-03-16

Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning pore and ligament sizes. The np-Au electrodes that are prepared using electrochemical techniques are robust and are easier to handle for their use in electrochemical biosensing. Here, we review different electrochemical strategies for the preparation, post-modification, and characterization of np-Au along with the synergistic use of both electrochemistry and np-Au for applications in biosensing.

Advances in modern sample preparation techniques using microwaves assisted chemistry for metal species determination (W1)

International Nuclear Information System (INIS)

Ponard, O.F.X.

2002-01-01

Full text: Sample preparation has long been the bottleneck of environmental analysis for both total and species specific analysis. Digestion, extraction and preparation of the analytes are relying on a series of chemical reactions. The introduction of microwave assisted sample preparation has first been viewed as a mean to accelerate the kinetics of digestion of the matrix for total elements and fast samples preparation procedures. However, the extensive development and success of microwave digestion procedures in total elemental analysis has now allowed to have a larger insight of the perspectives offered by this technique. Microwave technologies now offer to have a precise control of the temperature and indirectly control the reaction kinetics taking place during the sample preparation procedures. Microwave assisted chemistry permits to perform simultaneously the fundamental steps required for metal species extraction and derivatization. The number of sample preparation steps used for organotin or organomercury species have been reduced to one and the total time of sample preparation brought down for a few hours to some minutes. Further, the developments of GC/ICP/MS techniques allow to routinely use speciated isotopic dilution methods has internal probe of the chemical reactions. These new approaches allow us to use the addition of the labeled species for isotopic dilution as a mean to evaluate and follow the chemical processes taking place during the extraction procedure. These procedures will help us to understand and check for the stability of the analytes during the chemistry of the sample preparation procedure and bring some insights of the chemistry taking place during the extraction. Understanding the different mechanisms involved in the sample preparation steps will allow us in return to further improve all theses procedures and bring us to the horizon of 'on-line sample preparation and detection'. (author)

Structure and Properties of Multiwall Carbon Nanotubes/Polystyrene Composites Prepared via Coagulation Precipitation Technique

Directory of Open Access Journals (Sweden)

I. N. Mazov

2011-01-01

Full Text Available Coagulation technique was applied for preparation of multiwall carbon nanotube- (MWNT-containing polystyrene (PSt composite materials with different MWNT loading (0.5–10 wt.%. Scanning and transmission electron microscopies were used for investigation of the morphology and structure of produced composites. It was shown that synthesis of MWNT/PSt composites using coagulation technique allows one to obtain high dispersion degree of MWNT in the polymer matrix. According to microscopy data, composite powder consists of the polystyrene matrix forming spherical particles with diameter ca. 100–200 nm, and the surface of MWNT is strongly wetted by the polymer forming thin layer with 5–10 nm thickness. Electrical conductivity of MWNT/PSt composites was investigated using a four-probe technique. Observed electrical percolation threshold of composite materials is near to 10 wt.%, mainly due to the insulating polymer layer deposited on the surface of nanotubes. Electromagnetic response of prepared materials was investigated in broadband region (0.01–4 and 26–36 GHz. It was found that MWNT/PSt composites are almost radiotransparent for low frequency region and possess high absorbance of EM radiation at higher frequencies.

Optical ph sensing material prepared from doped sol-gel film for use in acid-base titration

OpenAIRE

Musa Ahmad; T.W. Tan

2017-01-01

An optical pH sensing material has been prepared in this study by using sol-gel technique. Bromothymol blue, bromophenol blue and thymol blue were chosen in this study as acidbase indicators for strong acid-strong base, strong acid-weak base and weak acid-strong base titration, respectively. The results show that these indicators could be successfully entrapped inside the sol-gel film and still maintain its chemical behaviour as in solution. The entrapped acid-base indicators respond well to ...

Preparation of TEM specimen by cross-section technique

International Nuclear Information System (INIS)

Hamada, Shozo

1986-01-01

Transmission electron microscopy (TEM) is applied to the direct observation of the depth dependent damage structure in ion-irradiated stainless steel by using the cross-section technique; obtaining the TEM specimen from a slice of the irradiated stainless steel with thick Ni plating. Here has been developed the specimen preparation method of cross-section technique without heat treatment, which was necessary in the conventional method to strengthen the bonding between Ni and stainless steel. Nickel plating with good bonding to stainless steel is enabled by the following manner. First, the irradiated stainless steel is immersed in the Wood's nickel solution at room temperature for 60s to activate the surface, followed by the stricking for 300s at a current density of 300 A/m 2 in the solution to make fine and homogeneous nucleation of Ni on the stainless steel. Then, the sample is plated with Ni in the Watt's nickel plating solution at 333 K with current density of 900 ∼ 1,000 A/m 2 . The TEM disc is obtained by mechanical slicing from the specimen with Ni plating of more than 3 mm thickness. Electropolishing is accomplished by using both Ballmann method and jet electropolishing to perforate the disc accurately at the aimed point for the observation of the damage structure. (author)

SKILLS-BASED ECLECTIC TECHNIQUES MATRIX FOR ELT MICROTEACHINGS

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İskender Hakkı Sarıgöz

2016-10-01

Full Text Available Foreign language teaching undergoes constant changes due to the methodological improvement. This progress may be examined in two parts. They are the methods era and the post-methods era. It is not pragmatic today to propose a particular language teaching method and its techniques for all purposes. The holistic inflexibility of mid-century methods has long gone. In the present day, constructivist foreign language teaching trends attempt to see the learner as a whole person and an individual who may be different from the other students in many respects. At the same time, the individual differences should not keep the learners away from group harmony. For this reason, current teacher training programs require eclectic teaching matrixes for unit design considering the mixed ability student groups. These matrixes can be prepared in a multidimensional fashion because there are many functional techniques in different methods and other new techniques to be created by instructors freely in accordance with the teaching aims. The hypothesis in this argument is that the collection of foreign language teaching techniques compiled in ELT microteachings for a particular group of learners has to be arranged eclectically in order to update the teaching process. Nevertheless, designing a teaching format of this sort is a demanding and highly criticized task. This study briefly argues eclecticism in language-skills based methodological struggle from the perspective of ELT teacher education.

Preparation and Characterization of Amorphous B Powders by Salt-Assisted SHS Technique

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Yujing Ou

2015-01-01

Full Text Available To use the salt-assisted SHS technique to prepare B powders was proposed. Calculation results found that the adiabatic combustion temperature of the B2O3-Mg reaction system was 2604 K, higher than the 1800 K criterion of self-propagating temperature, which meant that the SHS application was feasible. When 0, 10%, 20%, 30%, 40%, 50%, and 60% NaCl content were added, the adiabatic combustion temperature of the reaction system decreased linearly. When 60% NaCl content was added, the adiabatic combustion temperature was 1799 K (lower than 1800 K, unsuitable for self-propagating reaction, which was consistent with the experimental results. Through scanning electron microscope (SEM, energy disperse spectroscopy (EDS, and particle size analysis, the influence of different addition of NaCl on the morphology, average particle size, and purity of prepared B powder was investigated. EDS and chemical analysis indicated that the purity of prepared B powder was over 96% and the average particle size was within the range of 0.4~0.8 μm when the content of NaCl was 50%. The analysis of X-ray diffraction (XRD and selected area electron diffraction (SAED proved that the prepared B powder was amorphous.

Structural characterization of nanocrystalline cadmium sulphide powder prepared by solvent evaporation technique

Science.gov (United States)

Pandya, Samir; Tandel, Digisha; Chodavadiya, Nisarg

2018-05-01

CdS is one of the most important compounds in the II-VI group of semiconductor. There are numerous applications of CdS in the form of nanoparticles and nanocrystalline. Semiconductors nanoparticles (also known as quantum dots), belong to state of matter in the transition region between molecules and solids, have attracted a great deal of attention because of their unique electrical and optical properties, compared to bulk materials. In the field of optoelectronic, nanocrystalline form utilizes mostly in the field of catalysis and fluid technology. Considering these observations, presented work had been carried out, i.e. based on the nanocrystalline material preparation. In the present work CdS nano-crystalline powder was synthesized by a simple and cost effective chemical technique to grow cadmium sulphide (CdS) nanoparticles at 200 °C with different concentrations of cadmium. The synthesis parameters were optimized. The synthesized powder was structurally characterized by X-ray diffraction and particle size analyzer. In the XRD analysis, Micro-structural parameters such as lattice strain, dislocation density and crystallite size were analysed. The broadened diffraction peaks indicated nanocrystalline particles of the film material. In addition to that the size of the prepared particles was analyzed by particle size analyzer. The results show the average size of CdS particles ranging from 80 to 100 nm. The overall conclusion of the work can be very useful in the synthesis of nanocrystalline CdS powder.

Solution preparation

International Nuclear Information System (INIS)

Seitz, M.G.

1982-01-01

Reviewed in this statement are methods of preparing solutions to be used in laboratory experiments to examine technical issues related to the safe disposal of nuclear waste from power generation. Each approach currently used to prepare solutions has advantages and any one approach may be preferred over the others in particular situations, depending upon the goals of the experimental program. These advantages are highlighted herein for three approaches to solution preparation that are currently used most in studies of nuclear waste disposal. Discussion of the disadvantages of each approach is presented to help a user select a preparation method for his particular studies. Also presented in this statement are general observations regarding solution preparation. These observations are used as examples of the types of concerns that need to be addressed regarding solution preparation. As shown by these examples, prior to experimentation or chemical analyses, laboratory techniques based on scientific knowledge of solutions can be applied to solutions, often resulting in great improvement in the usefulness of results

Polysulfobetaine films prepared by electrografting technique for reduction of biofouling on electroconductive surfaces

International Nuclear Information System (INIS)

Stach, Marek; Kronekova, Zuzana; Kasak, Peter; Kollar, Jozef; Pentrak, Martin; Micusik, Matej; Chorvat, Dusan; Nunney, Tim S.; Lacik, Igor

2011-01-01

The sulfobetaine films were prepared on stainless steel and golden surfaces. In the first step, the poly(2-(dimethylamino)ethyl methacrylate) film was created by employing the electrografting polymerization technique. In the second step, this film was modified to polysulfobetaine, i.e. the polymer film bearing the zwitterionic groups. The presence of the electrografted film and its modification were determined by contact angle measurements, infrared spectroscopy in reflectance mode and X-ray photoelectron spectroscopy. The prepared films were homogeneous with the thickness from about 5 to 26 nm as determined by X-ray photoelectron spectroscopy. The atomic force microscopy measurements showed the increase of surface roughness upon the surface coating. In vitro tests using adherent RAT-2 fibroblast cells and fluorescently labelled bovine serum albumin proteins showed that prepared polysulfobetaine films can be used in applications requiring the resistance against cell attachment and biofouling.

Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques

Directory of Open Access Journals (Sweden)

Jay K. Bhattarai

2018-03-01

Full Text Available Nanoporous gold (np-Au, because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning pore and ligament sizes. The np-Au electrodes that are prepared using electrochemical techniques are robust and are easier to handle for their use in electrochemical biosensing. Here, we review different electrochemical strategies for the preparation, post-modification, and characterization of np-Au along with the synergistic use of both electrochemistry and np-Au for applications in biosensing.

Effect of screw access hole preparation on fracture load of implant-supported zirconia-based crowns: an in vitro study

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Hadi Mokhtarpour

2016-07-01

Full Text Available Background. Fracture load of implant-supported restorations is an important factor in clinical success. This study evaluated the effect of two techniques for screw access hole preparation on the fracture load of cement-screw-retained implant-supported zirconia-based crowns. Methods. Thirty similar cement-screw-retained implant-supported zirconia-based maxillary central incisor crowns were evaluated in three groups of 10. Group NH: with no screw access holes for the control; Group HBS: with screw access holes prepared with a machine before zirconia sintering; Group HAS: with screw access holes prepared manually after zirconia sintering. In group HBS, the access holes were virtually designed and prepared by a computer-assisted design/computer-assisted manufacturing system. In group HAS, the access holes were manually prepared after zirconia sintering using a diamond bur. The dimensions of the screw access holes were equal in both groups. The crowns were cemented onto same-size abutments and were then subjected to thermocycling. The fracture load values of the crowns were measured using a universal testing machine. Data were analyzed with ANOVA and Tukey test (P < 0.05. Results. The mean fracture load value for the group NH was 888.37 ± 228.92 N, which was the highest among the groups, with a significant difference (P < 0.0001. The fracture load values were 610.48 ± 125.02 N and 496.74 ± 104.10 Nin the HBS and HAS groups, respectively, with no significant differences (P = 0.44. Conclusion. Both techniques used for preparation of screw access holes in implant-supported zirconia-based crowns de-creased the fracture load.

Efficacy of two sperm preparation techniques in reducing non-specific bacterial species from human semen

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Prabath K Abeysundara

2013-01-01

Full Text Available Context: Artificial reproductive techniques using seminal preparations with bacteria may cause pelvic inflammatory disease and its sequalae. Aims: To assess efficacy of two sperm preparation techniques to clear bacteria and the effect of bacteriospermia on sperm recovery rates. Settings and Design: A descriptive cross-sectional study was carried out among males of subfertile couples. Subjects and Methods: Semen samples were randomly allocated into swim-up method (group S, n = 68 and density gradient method (group D, n = 50 for sperm preparation. Seminal fluid analysis and bacterial cultures were performed in each sample before and after sperm preparation. Statistical Analysis: McNemar′s chi-squared test and independent samples t-test in SPSS version 16.0 were used. Results: Organisms were found in 86 (72.88% out of 118 samples, before sperm preparation; Streptococcus species (n = 40, 46.51% of which 14 were Group D Streptococcus species, Coagulase negative Staphylococcus species (n = 17, 19.76%, Staphylococcus aureus (n = 13, 15.11%, Coliform species (n = 11, 12.79% of which 09 were Escherichia coli and Corynebacterium species (n = 5, 5.81%. There was a statistically significant reduction of culture positive samples in raw vs. processed samples; in group S, 49 (72.05% vs. 16 (23.52% and in group D, 37 (74% vs. 18 (36%. In group S and D, mean (SD recovery rates of culture positive vs. culture negative samples were 39.44% (SD-14.02 vs. 44.22% (SD-22.38, P = 0.39 and 52.50% (SD-37.16 vs. 49.58% (SD-40.32, P = 0.82 respectively. Conclusions: Both sperm preparation methods significantly reduced bacteria in semen, but total clearance was not achieved. Sperm recovery rate was not affected by bacteriospermia.

Preparation, Properties, and Self-Assembly Behavior of PTFE-Based Core-Shell Nanospheres

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Katia Sparnacci

2012-01-01

Full Text Available Nanosized PTFE-based core-shell particles can be prepared by emulsifier-free seed emulsion polymerization technique starting from spherical or rod-like PTFE seeds of different size. The shell can be constituted by the relatively high Tg polystyrene and polymethylmethacrylate as well as by low Tg polyacrylic copolymers. Peculiar thermal behavior of the PTFE component is observed due to the high degree of PTFE compartmentalization. A very precise control over the particle size can be exerted by properly adjusting the ratio between the monomers and the PTFE seed. In addition, the particle size distribution self-sharpens as the ratio monomer/PTFE increases. Samples with uniformity ratios suited to build 2D and 3D colloidal crystals are easily prepared. In particular, 2D colloidal crystal of spheres leads to very small 2D nanostructuration, useful for the preparation of masks with a combination of nanosphere lithography and reactive ion etching. 3D colloidal crystals were also obtained featuring excellent opal quality, which is a direct consequence of the monodispersity of colloids used for their growth.

Preparation, Properties, and Self-Assembly Behavior of PTFE-Based Core-Shell Nanospheres

International Nuclear Information System (INIS)

Sparnacci, K.; Antonioli, D.; Deregibus, S.; Laus, M.; Zuccheri, G.; Boarino, L.; De Leo, N.; Comoretto, D.

2012-01-01

Nano sized PTFE-based core-shell particles can be prepared by emulsifier-free seed emulsion polymerization technique starting from spherical or rod-like PTFE seeds of different size. The shell can be constituted by the relatively high Tg polystyrene and polymethylmethacrylate as well as by low Tg polyacrylic copolymers. Peculiar thermal behavior of the PTFE component is observed due to the high degree of PTFE compartmentalization. A very precise control over the particle size can be exerted by properly adjusting the ratio between the monomers and the PTFE seed. In addition, the particle size distribution self-sharpens as the ratio monomer/PTFE increases. Samples with uniformity ratios suited to build 2D and 3D colloidal crystals are easily prepared. In particular, 2D colloidal crystal of spheres leads to very small 2D nanostructuration, useful for the preparation of masks with a combination of nanosphere lithography and reactive ion etching. 3D colloidal crystals were also obtained featuring excellent opal quality, which is a direct consequence of the monodispersity of colloids used for their growth.

The study of preparation for immobilized cells membranes of E. Coli. by radiation technique

International Nuclear Information System (INIS)

Cao Jin; Chen Pin; Yu Yi

1991-01-01

The paper described the preparation of immobilized cells membranes with E. Coli by radiation technique. The nylon 6 was grafted with HEMA, which as a matrix to prepare immobilized cells membranes with E. Coli. by radiation entrapment at low temperature. The results showed that the retentive activity possessed a maximum value for membranes with E. Coli. when the irradiation dose was at 10-12 kGy, the entrapped cells has 2.3 g/ml at 50% HEMA concentration, the optimum pH and optimum temperature for membranes with E. Coli. are as same the original cells

Preparation of HfC single crystals by a floating zone technique

International Nuclear Information System (INIS)

Otani, S.; Tanaka, T.

1981-01-01

HfC single crystals have been prepared using a floating zone technique by controlling the compositions of the initial molten zone and the feed rod. The obtained crystal rods were 6 cm long and 0.9 cm in diameter. The various parts of the crystal rods have nearly constant compositions (C/Hf(ZR) = 0.956-0.977), and do not contain any free carbon. The impurities in the crystal, evaporation product, and starting material were examined by fluorescence X-ray spectroscopy. The refining effect due to evaporation was discussed. (orig.)

Application of green chemistry techniques to prepare electrocatalysts for direct methanol fuel cells.

Science.gov (United States)

Shimizu, Kenichi; Wang, Joanna S; Wai, Chien M

2010-03-25

A series of green techniques for synthesizing carbon nanotube-supported platinum nanoparticles and their high electrocatalytic activity toward methanol fuel cell applications are reported. The techniques utilize either the supercritical fluid carbon dioxide or water as a medium for depositing platinum nanoparticles on surfaces of multiwalled or single-walled carbon nanotubes. The catalytic properties of the carbon nanotubes-supported Pt nanoparticle catalysts prepared by four different techniques are compared for anodic oxidation of methanol and cathodic reduction of oxygen using cyclic voltammetry. One technique using galvanic exchange of Pt(2+) in water with zerovalent iron present on the surfaces of as-grown single-walled carbon nanotubes produces a Pt catalyst that shows an unusually high catalytic activity for reduction of oxygen but a negligible activity for oxidation of methanol. This fuel-selective catalyst may have a unique application as a cathode catalyst in methanol fuel cells to alleviate the problems caused by crossover of methanol through the polymer electrolyte membrane.

Ultraviolet electroluminescence from nitrogen-doped ZnO-based heterojuntion light-emitting diodes prepared by remote plasma in situ atomic layer-doping technique.

Science.gov (United States)

Chien, Jui-Fen; Liao, Hua-Yang; Yu, Sheng-Fu; Lin, Ray-Ming; Shiojiri, Makoto; Shyue, Jing-Jong; Chen, Miin-Jang

2013-01-23

Remote plasma in situ atomic layer doping technique was applied to prepare an n-type nitrogen-doped ZnO (n-ZnO:N) layer upon p-type magnesium-doped GaN (p-GaN:Mg) to fabricate the n-ZnO:N/p-GaN:Mg heterojuntion light-emitting diodes. The room-temperature electroluminescence exhibits a dominant ultraviolet peak at λ ≈ 370 nm from ZnO band-edge emission and suppressed luminescence from GaN, as a result of the decrease in electron concentration in ZnO and reduced electron injection from n-ZnO:N to p-GaN:Mg because of the nitrogen incorporation. The result indicates that the in situ atomic layer doping technique is an effective approach to tailoring the electrical properties of materials in device applications.

Titanium-silicon films prepared by spin and dip-coating

International Nuclear Information System (INIS)

Nassar, Eduardo J.; Ciuffi, Katia J.; Goncalves, Rogeria R.; Messaddeq, Younes; Ribeiro, Sidney J.L.

2003-01-01

The conditions for the preparation of luminescent materials, consisting of Eu 3+ ions entrapped in a titanium matrix, in the form of a thin film, using the sol-gel process, are described. The films were obtained from sols prepared with TEOS and TEOT, in the presence of acetylacetone as the hydrolysis-retarding agent, using the dip-coating and spin-coating techniques. The influence of these techniques on the films based on titanium and silicon are presented. The Eu 3+ was used as a luminescent probe. The films have been characterized by luminescence, reflection and transmittance. The thickness of the films could be related to the preparation procedure. Transparent thin films have been prepared by dip-coating technique. (author)

Analysis of preparation of Chinese traditional medicine based on the fiber fingerprint drop trace

Science.gov (United States)

Zhang, Zhilin; Wang, Jialu; Sun, Weimin; Yan, Qi

2010-11-01

The purpose of the fiber micro-drop analyzing technique is to measure the characteristics of liquids using optical methods. The fiber fingerprint drop trace (FFDT) is a curve of light intensity vs. time. This curve indicates the forming, growing and dripping processes of the liquid drops. A pair of fibers was used to monitor the dripping process. The FFDTs are acquired and analyzed by a computer. Different liquid samples of many kinds of preparation of Chinese traditional medicines were tested by using the fiber micro-drop sensor in the experiments. The FFDTs of preparation of Chinese traditional medicines with different concentrations were analyzed in different ways. Considering the characters of the FFDTs, a novel method is proposed to measure the different preparation of Chinese traditional medicines and its concentration based on the corresponding relationship of FFDTs and the physical and chemical parameters of the liquids.

Preparation and characterization of VOx nanorods using pulsed laser deposition technique

International Nuclear Information System (INIS)

Rama, N.; Senthil Kumar, E.; Ramachandra Rao, M.S.

2009-01-01

Full text: Vanadium oxide (VO x ) is one of the most functional oxides of the transition metal oxide family. This versatility comes because of the ability of Vanadium to exist as both monovalent and multivalent in these oxides. These oxides find potential usage in the field of thermochromism electrochromism catalysts, electrochemistry etc. especially in their nano-form because of their increased sensitivity to these applications. These nano-forms are usually prepared using conventional techniques such as solgel techniques, vapour phase transport, hydrothermal synthesis etc. In this work we have used pulsed laser deposition technique to fabricate vanadium oxide nanorods for the first time. The grown nanorods has a predominant VO 2 phase with a secondary phase of V 3 O 7 . The diameters of the rods were around 300 nm with Raman spectra showing all the group vibrations corresponding to VO x phase. The nanorods exhibited photoluminescence in the visible range due to the presence of oxygen defects. These results, including the mechanism of growth of these nanorods, will be discussed in detail. The existence of multivalence in these rods finds potential applications in electrochemistry while the visible photoluminescence in optical applications

Development Model of Basic Technique Skills Training Shot-Put Obrien Style Based Biomechanics Review

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danang rohmat hidayanto

2018-03-01

Full Text Available The background of this research is the unavailability of learning model of basic technique technique of O'Brien style force that integrated in skill program based on biomechanics study which is used as a reference to build the basic technique skill of the O'Brien style force among students. The purpose of this study is to develop a model of basic-style technique of rejecting the O'Brien-style shot put based on biomechanical studies for beginner levels, including basic prefix technique, glide, final stage, repulsion, further motion and repulsion performance of O'Brien style, all of which arranged in a medium that is easily accessible whenever, by anyone and anywhere, especially in SMK Negeri 1 Kalijambe Sragen . The research method used is "Reasearch and Developement" approach. "Preliminary studies show that 43.0% of respondents considered that the O'Brien style was very important to be developed with a model of skill-based exercise based on biomechanics, as many as 40.0% ressponden stated that it is important to be developed with biomechanics based learning media. Therefore, it is deemed necessary to develop the learning media of the O'Brien style-based training skills based on biomechanical studies. Development of media starts from the design of the storyboard and script form that will be used as media. The design of this model is called the draft model. Draft models that have been prepared are reviewed by the multimedia expert and the O'Brien style expert to get the product's validity. A total of 78.24% of experts declare a viable product with some input. In small groups with n = 6, earned value 72.2% was obtained or valid enough to be tested in large groups. In the large group test with n = 12,values obtained 70.83% or quite feasible to be tested in the field. In the field test, experimental group was prepared with treatment according to media and control group with free treatment. From result of counting of significance test can be

Preparation of functionalized carbon nanotubes using radiation technique

International Nuclear Information System (INIS)

Chen Shimou; Wu Guozhong; Huang Shirong; Zhu Guanglai

2006-01-01

Carbon nanotubes (CNTs) have attracted great interest because of their unique structural, electronic, mechanical, and optical properties. However, the studies and applications of CNTs are hindered by processing and manipulation difficulties owing to their insolubility or poor dispersion in common solvents and polymeric matrixes. To facilitate their applications, many approaches were employed to functionalize CNTs with functional groups, either noncovalently or covalently. In our study, radiation technique was utilized to produce functionalized CNTs. In a typical experiment, multiwalled carbon nanotubes (MWNTs) were irradiated in potassium persulfate aqueous solution. Persulfnic group can react with hydrated electrons to produce sulfuric acid radicals, which can attack the c=c on the surface of tubes to form sulfonated MWNTs. On the other hand, grafting polymer (instead of low-molecular-weight compound) onto CNTs by an appropriate method is a possible strategy for preparing the nanotubes with little damage in structure and high solubility in solvent. A facile strategy to prepare water soluble MWNTs in large scale by two steps of gamma irradiation has been developed at SINAP. The first step is to irradiate MWNTs in ethanol. The radiolysis of ethanol produced many active species such as . CH 2 CH 2 OH, CH 3 . CHCH 2 OH, which react with C=C of MWNTs and attach onto the surface of MWNTs. Then, poly(acrylic acid) was covalently grafted to the surface of MWNTs by irradiating the samples in the presence of acrylic acid. The PAA-grafted MWNTs have good solubility in water and other polar solvents. This two-step grafting approach may also be of help for introducing other functional polymer chains onto MWNTs. (authors)

Optical ph sensing material prepared from doped sol-gel film for use in acid-base titration

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Musa Ahmad

2017-11-01

Full Text Available An optical pH sensing material has been prepared in this study by using sol-gel technique. Bromothymol blue, bromophenol blue and thymol blue were chosen in this study as acidbase indicators for strong acid-strong base, strong acid-weak base and weak acid-strong base titration, respectively. The results show that these indicators could be successfully entrapped inside the sol-gel film and still maintain its chemical behaviour as in solution. The entrapped acid-base indicators respond well to any pH changes and could be used to determine the end-point of the acid-base titration.

Study of PDMS conformation in PDMS-based hybrid materials prepared by gamma irradiation

International Nuclear Information System (INIS)

Lancastre, J.J.H.; Fernandes, N.; Margaça, F.M.A.; Miranda Salvado, I.M.; Ferreira, L.M.; Falcão, A.N.; Casimiro, M.H.

2012-01-01

Polydimethylsiloxane-silicate based hybrid materials have recognized properties (high flexibility, low elastic modulus or high mechanical strength) for which there are a large number of applications in development, such as for the bioapplications field. The hybrids addressed in the present study were prepared by gamma irradiation of a mixture of polydimethylsiloxane (PDMS) with tetraethylorthosilicate (TEOS) and zirconium propoxide (PrZr) without addition of any solvent or other product. The materials are homogeneous, transparent, monolithic and flexible. The structure dependence on the PrZr content is addressed. A combination of X-ray diffraction (XRD) and Infrared Spectroscopy (IR) was used. The results reveal that the polymer in the hybrids prepared with PrZr, in a content≤5 wt%, shows a structure similar to that in the irradiated pure polymer sample. In these samples the presence of ordered polymer regions is clearly found. For samples prepared with higher content of Zr almost no ordered polymer regions are observed. The addition of PrZr plays an important role on polymer conformation in these hybrid materials. - Highlights: ► PDMS-based hybrid materials were prepared by γ-irradiation. ► FTIR, ATR/FT-IR and XRD techniques were used to characterize the materials. ► Changes in FTIR bands reflect growth of crosslinking network. ► Above certain Zr concentration regions of Zr-silicate oxide are formed. ► Zr content determines conformation of the polymer chain network.

Electrochemical preparation of MnO2 nanobelts through pulse base-electrogeneration and evaluation of their electrochemical performance

Science.gov (United States)

Aghazadeh, Mustafa; Maragheh, Mohammad Ghannadi; Ganjali, Mohammad Reza; Norouzi, Parviz; Faridbod, Farnoush

2016-02-01

Cathodic electrodeposition of MnO2 from a nitrate solution, via pulsed base (OH-) electrogeneration was performed for the first time. The deposition experiments were performed in a pulse current mode in typical on-times and off-times (i.e. ton = 1 s and toff = 1 s) with a peak current density of 2 mA cm-2 (Ia = 2 mA cm-2). The structural characterizations conducted by XRD and FTIR techniques revealed that the prepared MnO2 is composed of both α and γ phases. Morphological observation by SEM and TEM showed that the prepared MnO2 is made up of nanobelts with uniform shapes (an average diameter and length of 50 nm and 1 μm, respectively). Further electrochemical measurements by cyclic voltammetry and charge-discharge techniques revealed that the prepared MnO2 nanostructures have excellent capacitive behaviors, like a specific capacitance of 235.5 F g-1 and capacity retention of 91.3% after 1000 cycling at the scan rate of 25 mV s-1.

Preparation and leaching property of Nd-doped zirconolite-based glass-ceramic

International Nuclear Information System (INIS)

Wu Lang; Xu Dong; Teng Yuancheng; Li Yuxiang; Liu Zongqiang

2014-01-01

Nd-doped zirconolite-based glass-ceramics were prepared by melting-heat treatment technique. The effects of heat treatment processing on phase structure of the glass-ceramics were investigated. The leaching properties of the glass-ceramics were also evaluated by static leaching experiments (product consistency test, PCT). The results show that glass transformation temperature (T g ) and crystallization temperature of the glass-ceramics are about 580℃ and 740℃, respectively. CaTiO 3 phase forms easily when the glass-ceramics were prepared by two-step method, i.e. the glass was prepared first, and then it was heat-treated at the crystallization temperatures. 2M-zirconolite phase can be obtained by one-step method, i.e. the heat-treatment immediately followed by the melting process. In addition, the zirconolite crystals exhibit a dendritic shape. The normalized mass loss of B and Na in the glass-ceramics remains almost unchanged (about 1 mg/m 2 ) after 14 days, while the normalized mass loss of Nd reaches stable value (about 0.2 mg/m 2 ) after 28 days. The normalized mass loss of B, Na, and Nd in the glass-ceramics is an order of magnitude lower than that of borosilicate glasses, respectively. (authors)

Capillarity-based preparation system for optical colorimetric sensor arrays.

Science.gov (United States)

Luo, Xiao-Gang; Yi, Xin; Bu, Xiang-Nan; Hou, Chang-Jun; Huo, Dan-Qun; Yang, Mei; Fa, Huan-Bao; Lei, Jin-Can

2017-03-01

In recent years, optical colorimetric sensor arrays have demonstrated beneficial features, including rapid response, high selectivity, and high specificity; as a result, it has been extensively applied in food inspection and chemical studies, among other fields. There are instruments in the current market available for the preparation of an optical colorimetric sensor array, but it lacks the corresponding research of the preparation mechanism. Therefore, in connection with the main features of this kind of sensor array such as consistency, based on the preparation method of contact spotting, combined with a capillary fluid model, Washburn equation, Laplace equation, etc., this paper develops a diffusion model of an optical colorimetric sensor array during its preparation and sets up an optical colorimetric sensor array preparation system based on this diffusion model. Finally, this paper compares and evaluates the sensor arrays prepared by the system and prepared manually in three aspects such as the quality of array point, response of array, and response result, and the results show that the performance index of the sensor array prepared by a system under this diffusion model is better than that of the sensor array of manual spotting, which meets the needs of the experiment.

Effect of Post Space Preparation on Apical Obturation Quality of Teeth Obturated with Different Techniques: A Micro-computed Tomographic Study.

Science.gov (United States)

Küçükkaya Eren, Selen; Askerbeyli Örs, Sevinc; Yılmaz, Zeliha

2017-07-01

The purpose of this study was to evaluate the obturation quality of root canals filled with different techniques and to determine whether post space preparation had an effect on the quality of apical obturation using micro-computed tomographic (micro-CT) imaging. The root canals of 30 human mandibular premolar teeth were instrumented, and the specimens were divided into 3 groups according to the obturation technique used: cold lateral compaction (CLC), warm vertical compaction (WVC), or single-cone (SC) techniques. The specimens were stored at 37°C and 100% humidity for 1 week. Then, the coronal root filling material was removed in order to create a post space. Micro-CT scans were performed before and after post space preparation for the volumetric analysis of voids and filling materials. Data were analyzed using repeated-measures analysis of variance and Bonferroni tests. The CLC and SC groups showed a significantly greater percentage volume of voids than the WVC group (P space preparation (P > .05). The post space preparation caused a significant increase in the percentage volume of voids in the CLC and SC groups (P space preparation (P > .05). No root fillings were void free. The WVC group presented the best obturation quality. The post space preparation negatively influenced the apical integrity of the filling materials in the CLC and SC groups, whereas it had no significant effect in the WVC group. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

GIS-based bivariate statistical techniques for groundwater potential analysis (an example of Iran)

Science.gov (United States)

Haghizadeh, Ali; Moghaddam, Davoud Davoudi; Pourghasemi, Hamid Reza

2017-12-01

Groundwater potential analysis prepares better comprehension of hydrological settings of different regions. This study shows the potency of two GIS-based data driven bivariate techniques namely statistical index (SI) and Dempster-Shafer theory (DST) to analyze groundwater potential in Broujerd region of Iran. The research was done using 11 groundwater conditioning factors and 496 spring positions. Based on the ground water potential maps (GPMs) of SI and DST methods, 24.22% and 23.74% of the study area is covered by poor zone of groundwater potential, and 43.93% and 36.3% of Broujerd region is covered by good and very good potential zones, respectively. The validation of outcomes displayed that area under the curve (AUC) of SI and DST techniques are 81.23% and 79.41%, respectively, which shows SI method has slightly a better performance than the DST technique. Therefore, SI and DST methods are advantageous to analyze groundwater capacity and scrutinize the complicated relation between groundwater occurrence and groundwater conditioning factors, which permits investigation of both systemic and stochastic uncertainty. Finally, it can be realized that these techniques are very beneficial for groundwater potential analyzing and can be practical for water-resource management experts.

Coordination chemistry of actinide elements: preparation of new uranium complexes with schiff bases and their characterization (Preprint No. CT-31)

International Nuclear Information System (INIS)

Hingorani, S.; Reddy, P.S.N.; Agarwala, B.V.

1988-02-01

The Schiff bases, o-vanillin semicarbazone (oVSC) and 2-pyridine carboxaldehyde isonicotinoyl hydrazone (PCINH) have been prepared and their novel complexes with dioxouranium(VI) have been synthesized and characterized by IR spectra, elemental analysis and other physico-chemical techniques. (author)

Technique of sample preparation for analysis of gasoline and lubricating oils by X-ray fluorescence analysis

International Nuclear Information System (INIS)

Avila P, P.

1990-03-01

The X-ray fluorescence laboratory of the National Institute of Nuclear Research when not having a technique for the analysis of oils it has intended, with this work, to develop a preparation technique for the analysis of the metals of Pb, Cr, Ni, V and Mo in gasolines and oils, by means of the spectrometry by X-ray fluorescence analysis. The obtained results, its will be of great utility for the one mentioned laboratory. (Author)

Research Progress on Preparation for Biomass-based SiC Ceramic

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CUI He-shuai

2017-08-01

Full Text Available Silicon carbide (SiC ceramics prepared by the conventional process has excellent properties and wide application prospects, but the increased cost of high-temperature preparation process restricts its further development. In contrast, the abundant porous structure of biomass makes itself to be ideal replacement of SiC ceramic prepared at low temperature. This paper reviewed the structure characteristics, preparation methods, pyrolysis mechanism and influence parameters of biomass-based SiC ceramic, and eventually explored the current problems and development trends of the pretreatment of carbon source and silicon source, the pyrolysis process and the application research on the preparation for biomass-based SiC ceramic.

The performance of silicon solar cells prepared by screen-printing technique

International Nuclear Information System (INIS)

Mursyidah; Mohamed Yahaya; Muhammad Mohd Salleh

2000-01-01

Screen-printing technique is known to produce low cost solar cells. A study has been done to prepare silicon solar cells of n + -p and n + -p-p + structures. The p-type silicon wafers were used as substrates. The phosphorous layer was deposited on top of the substrate using the screen-printing technique. The wafer was then annealed at temperature 1000 degree C for 10 minutes, so that phosphorous atoms are thermally diffused into the wafer to form an n + -p junction. Meanwhile the boron film was deposited at the back surface of the substrate and annealed at temperature 900 degree C for 10 minutes to form a p + layer in the n + -p-p + device. The back and front metal contacts were made using screen-printing technique. The performance of the devices was evaluated from I-V curves measured in the dark and under illumination. It was found that the n + -p-p + device with short circuit current, I SC = 32 mA, open circuit voltage, V OC = 0.46 volt, fill factor, FF=0.63 and efficiency, η = 2.3%, was better than that of the n + -p device. The performance of the n + -p-p + device was successfully improved by depositing titanium dioxide on top of the device as anti-reflection coating using the screen-printing technique. The improved performance was I SC = 38 mA, V OC = 0.48 volt, FF = 0.67 and η = 3. 1%. (Author)

Enhanced dissolution and oral bioavailability of valsartan solid dispersions prepared by a freeze-drying technique using hydrophilic polymers.

Science.gov (United States)

Xu, Wei-Juan; Xie, Hong-Juan; Cao, Qing-Ri; Shi, Li-Li; Cao, Yue; Zhu, Xiao-Yin; Cui, Jing-Hao

2016-01-01

This study aimed to improve the dissolution rate and oral bioavailability of valsartan (VAL), a poorly soluble drug using solid dispersions (SDs). The SDs were prepared by a freeze-drying technique with polyethylene glycol 6000 (PEG6000) and hydroxypropylmethylcellulose (HPMC 100KV) as hydrophilic polymers, sodium hydroxide (NaOH) as an alkalizer, and poloxamer 188 as a surfactant without using any organic solvents. In vitro dissolution rate and physicochemical properties of the SDs were characterized using the USP paddle method, differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and Fourier transform-infrared (FT-IR) spectroscopy, respectively. In addition, the oral bioavailability of SDs in rats was evaluated by using VAL (pure drug) as a reference. The dissolution rates of the SDs were significantly improved at pH 1.2 and pH 6.8 compared to those of the pure drug. The results from DSC, XRD showed that VAL was molecularly dispersed in the SDs as an amorphous form. The FT-IR results suggested that intermolecular hydrogen bonding had formed between VAL and its carriers. The SDs exhibited significantly higher values of AUC 0-24 h and Cmax in comparison with the pure drug. In conclusion, hydrophilic polymer-based SDs prepared by a freeze-drying technique can be a promising method to enhance dissolution rate and oral bioavailability of VAL.

Recent mass spectrometry-based techniques and considerations for disulfide bond characterization in proteins.

Science.gov (United States)

Lakbub, Jude C; Shipman, Joshua T; Desaire, Heather

2018-04-01

Disulfide bonds are important structural moieties of proteins: they ensure proper folding, provide stability, and ensure proper function. With the increasing use of proteins for biotherapeutics, particularly monoclonal antibodies, which are highly disulfide bonded, it is now important to confirm the correct disulfide bond connectivity and to verify the presence, or absence, of disulfide bond variants in the protein therapeutics. These studies help to ensure safety and efficacy. Hence, disulfide bonds are among the critical quality attributes of proteins that have to be monitored closely during the development of biotherapeutics. However, disulfide bond analysis is challenging because of the complexity of the biomolecules. Mass spectrometry (MS) has been the go-to analytical tool for the characterization of such complex biomolecules, and several methods have been reported to meet the challenging task of mapping disulfide bonds in proteins. In this review, we describe the relevant, recent MS-based techniques and provide important considerations needed for efficient disulfide bond analysis in proteins. The review focuses on methods for proper sample preparation, fragmentation techniques for disulfide bond analysis, recent disulfide bond mapping methods based on the fragmentation techniques, and automated algorithms designed for rapid analysis of disulfide bonds from liquid chromatography-MS/MS data. Researchers involved in method development for protein characterization can use the information herein to facilitate development of new MS-based methods for protein disulfide bond analysis. In addition, individuals characterizing biotherapeutics, especially by disulfide bond mapping in antibodies, can use this review to choose the best strategies for disulfide bond assignment of their biologic products. Graphical Abstract This review, describing characterization methods for disulfide bonds in proteins, focuses on three critical components: sample preparation, mass

Comparison of liquid-based preparation and conventional smear of fine-needle aspiration cytology of lymph node

Directory of Open Access Journals (Sweden)

Priya Singh

2016-01-01

Conclusions: Liquid-based cytology (LBC is a relatively simple technique, which exhibits good nuclear and cytoplasmic details with the absence of obscuring background material. Even the number of slides and area per slide to be screened were less than the conventional preparation but caution must be applied to interpret the slides and secure a diagnosis, especially if LBC is the first and only method applied for diagnosis.

Micro-electrodeposition techniques for the preparation of small actinide counting sources for ultra-high resolution alpha spectrometry by microcalorimetry

International Nuclear Information System (INIS)

Plionis, A.A.; Hastings, E.P.; LaMont, S.P.; Dry, D.E.; Bacrania, M.K.; Rabin, M.W.; Rim, J.H.

2009-01-01

Special considerations and techniques are desired for the preparation of small actinide counting sources. Counting sources have been prepared on metal disk substrates (planchets) with an active area of only 0.079 mm 2 . This represents a 93.75% reduction in deposition area from standard electrodeposition methods. The actinide distribution upon the smaller planchet must remain thin and uniform to allow alpha particle emissions to escape the counting source with a minimal amount of self-attenuation. This work describes the development of micro-electrodeposition methods and optimization of the technique with respect to deposition time and current density for various planchet sizes. (author)

Studies of LENRA-Toughened PVC non-woven membranes prepared by electro spinning technique

International Nuclear Information System (INIS)

Dahlan Mohd; Mahathir Mohamed; Khirul Hafiz mohd Yusof

2010-01-01

Lately research in use of so-called green chemicals draws strong interest from research community due to the climate change issues. Malaysia is in strong position to take this advantage because we are among the world biggest producers of natural rubber and palm oil - the two sources of important green renewable chemical feedstock in the near future. For the last couple of years we have shown how modified natural rubbers especially liquid natural rubber and its derivatives such as liquid epoxidized natural rubber acrylate (LENRA) could be used in various applications via among others sol-gel technique and radiation curing technology. This time around we will show another application on how non-woven membranes made from PVC can be prepared by electro spinning technique using radiation curable LENRA as toughener. The electro spinning technique has great potential in producing nano fiber materials to be used in various applications to ensure sustainable energy and environments for the future. (author)

Assessment of three root canal preparation techniques on root canal geometry using micro-computed tomography: In vitro study

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Shaikha M Al-Ali

2012-01-01

Full Text Available Aim: To assess the effects of three root canal preparation techniques on canal volume and surface area using three-dimensionally reconstructed root canals in extracted human maxillary molars. Materials and Methods: Thirty extracted Human Maxillary Molars having three separate roots and similar root shape were randomly selected from a pool of extracted teeth for this study and stored in normal saline solution until used. A computed tomography scanner (Philips Brilliance CT 64-slice was used to analyze root canals in extracted maxillary molars. Specimens were scanned before and after canals were prepared using stainless steel K-Files, Ni-Ti rotary ProTaper and rotary SafeSiders instruments. Differences in dentin volume removed, the surface area, the proportion of unchanged area and canal transportation were calculated using specially developed software. Results: Instrumentation of canals increased volume and surface area. Statistical analysis found a statistically significant difference among the 3 groups in total change in volume (P = 0.001 and total change in surface area (P = 0.13. Significant differences were found when testing both groups with group III (SafeSiders. Significant differences in change of volume were noted when grouping was made with respect to canal type (in MB and DB (P < 0.05. Conclusion: The current study used computed tomography, an innovative and non destructive technique, to illustrate changes in canal geometry. Overall, there were few statistically significant differences between the three instrumentation techniques used. SafeSiders stainless steel 40/0.02 instruments exhibit a greater cutting efficiency on dentin than K-Files and ProTaper. CT is a new and valuable tool to study root canal geometry and changes after preparation in great details. Further studies with 3D-techniques are required to fully understand the biomechanical aspects of root canal preparation.

Preparation and characterization of etoricoxib solid dispersions using lipid carriers by spray drying technique

OpenAIRE

Chauhan, Bhaskar; Shimpi, Shyam; Paradkar, Anant

2005-01-01

The basic objectives of this study were to prepare and characterize solid dispersions of poorly water-soluble drug etoricoxib using lipid carriers by spray drying technique. The properties of solid dispersions were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), differential scanning calorimetry (DSC), hotstage microscopy (HSM), radiograph powder diffraction (XRPD), and dissolution studies. The absence of etoricoxib peaks in XRPD profiles of solid dispersions ...

A new hysteroscopic technique for the preparation of partially intramural myomas in office setting (OPPIuM technique): A pilot study.

Science.gov (United States)

Bettocchi, Stefano; Di Spiezio Sardo, Attilio; Ceci, Oronzo; Nappi, Luigi; Guida, Maurizio; Greco, Elena; Pinto, Lauro; Camporiale, Anna Lina; Nappi, Carmine

2009-01-01

To assess the safety and the effectiveness of a novel hysteroscopic technique for the Office Preparation of Partially Intramural Myomas (OPPIuM), to facilitate the subsequent, already scheduled, resectoscopic myomectomy. Pilot study. University of Bari, Naples and Foggia. Fifty-nine fertile women (age 27-48 years) diagnosed at office hysteroscopy as having symptomatic submucous myomas>1.5 cm with intramural development (G1 and G2), scheduled for resectoscopic surgery. The OPPIuM technique consisted of an incision of the endometrial mucosa covering the myoma by means of Fr scissors or bipolar Versapoint Twizzle electrode, along its reflection line on the uterine wall, up to the precise identification of the cleavage surface between the myoma and its pseudo-capsule. Such procedure was aimed at triggering the protrusion of the intramural portion of the myoma into the uterine cavity during the following menstrual cycles, thus facilitating the subsequent total removal of the lesion via resectoscopic surgery. All patients underwent follow-up in-patient hysteroscopy after 2 menstrual cycles before resectoscopic surgery were performed. The OPPIuM technique was successfully performed in all cases. The mean diameter of successfully prepared myomas was 2.9+/-0.8 cm. At follow-up hysteroscopy, the conversion of partially intramural myomas into totally or prevalently intracavitary ones was observed in 93.2% (55/59) of cases. In 2 of 3 cases of failure, the myomas' size was>4 cm. One patient was excluded from the study because of the occurrence of total spontaneous expulsion of the myoma at the subsequent menstrual cycle. Our preliminary findings seem to support the safety and the effectiveness of the OPPIuM procedure by reporting the conversion of myomas with intramural development>1.5 cm into totally or prevalently intracavitary ones in nearly 93% of cases. Such technique may allow surgeons to perform resectoscopic surgery more safely and quickly as dealing with prevalently

Microtomography-based comparison of reciprocating single-file F2 ProTaper technique versus rotary full sequence.

Science.gov (United States)

Paqué, Frank; Zehnder, Matthias; De-Deus, Gustavo

2011-10-01

A preparation technique with only 1 single instrument was proposed on the basis of the reciprocating movement of the F2 ProTaper instrument. The present study was designed to quantitatively assess canal preparation outcomes achieved by this technique. Twenty-five extracted human mandibular first molars with 2 separate mesial root canals were selected. Canals were randomly assigned to 1 of the 2 experimental groups: group 1, rotary conventional preparation by using ProTaper, and group 2, reciprocate instrumentation with 1 single ProTaper F2 instrument. Specimens were scanned initially and after root canal preparation with an isotropic resolution of 20 μm by using a micro-computed tomography system. The following parameters were assessed: changes in dentin volume, percentage of shaped canal walls, and degree of canal transportation. In addition, the time required to reach working length with the F2 instrument was recorded. Preoperatively, there were no differences regarding root canal curvature and volume between experimental groups. Overall, instrumentation led to enlarged canal shapes with no evidence of preparation errors. There were no statistical differences between the 2 preparation techniques in the anatomical parameters assessed (P > .01), except for a significantly higher canal transportation caused by the reciprocating file in the coronal canal third. On the other hand, preparation was faster by using the single-file technique (P ProTaper technique and conventional ProTaper full-sequence rotary approach were similar. However, the single-file F2 ProTaper technique was markedly faster in reaching working length. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

SEM-based characterization techniques

International Nuclear Information System (INIS)

Russell, P.E.

1986-01-01

The scanning electron microscope is now a common instrument in materials characterization laboratories. The basic role of the SEM as a topographic imaging system has steadily been expanding to include a variety of SEM-based analytical techniques. These techniques cover the range of basic semiconductor materials characterization to live-time device characterization of operating LSI or VLSI devices. This paper introduces many of the more commonly used techniques, describes the modifications or additions to a conventional SEM required to utilize the techniques, and gives examples of the use of such techniques. First, the types of signals available from a sample being irradiated by an electron beam are reviewed. Then, where applicable, the type of spectroscopy or microscopy which has evolved to utilize the various signal types are described. This is followed by specific examples of the use of such techniques to solve problems related to semiconductor technology. Techniques emphasized include: x-ray fluorescence spectroscopy, electron beam induced current (EBIC), stroboscopic voltage analysis, cathodoluminescnece and electron beam IC metrology. Current and future trends of some of the these techniques, as related to the semiconductor industry are discussed

Comparative study of nano copper aluminate spinel prepared by sol–gel and modified sol–gel techniques: Structural, electrical, optical and catalytic studies

International Nuclear Information System (INIS)

Kumar, R. Thinesh; Suresh, P.; Selvam, N. Clament Sagaya; Kennedy, L. John; Vijaya, J. Judith

2012-01-01

Highlights: ► A modified sol–gel method for the preparation of nano CuAl 2 O 4 spinel using ethylenediamine was studied. ► Role of ethylenediamine in enhancing the structural, electrical, optical and catalytic properties of copper aluminate is highlighted. ► Effect of preparation method on the activity and selectivity of the samples on the oxidation of benzyl alcohol by CuAl 2 O 4 is studied. - Abstract: The effect of ethylenediamine addition in the sol–gel method for the preparation of nano CuAl 2 O 4 spinel for the enhancement in their structural, electrical, optical and catalytic properties was investigated. The samples were prepared by two different methods: sol–gel and modified sol–gel technique using ethylenediamine. X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), high resolution-transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption isotherms, temperature dependent conductance measurements, thermoelectric power (TEP) measurements and UV–visible diffuse reflectance (UV–vis-DRS) spectra were used to characterize the samples prepared. CuAl 2 O 4 prepared by modified sol–gel technique was found to possess a higher surface area, lower crystallite size, lower activation energy and high porosity than the one prepared by sol–gel method which in turn lead to the improved performance of it towards the selective oxidation of benzyl alcohol to benzaldehyde. Effect of solvent on the catalytic oxidation of benzyl alcohol by the nano CuAl 2 O 4 prepared by modified sol–gel technique was also investigated.

Sample preparation techniques of biological material for isotope analysis

International Nuclear Information System (INIS)

Axmann, H.; Sebastianelli, A.; Arrillaga, J.L.

1990-01-01

Sample preparation is an essential step in all isotope-aided experiments but often it is not given enough attention. The methods of sample preparation are very important to obtain reliable and precise analytical data and for further interpretation of results. The size of a sample required for chemical analysis is usually very small (10mg-1500mg). On the other hand the amount of harvested plant material from plots in a field experiment is often bulky (several kilograms) and the entire sample is too large for processing. In addition, while approaching maturity many crops show not only differences in physical consistency but also a non-uniformity in 15 N content among plant parts, requiring a plant fractionation or separation into parts (vegetative and reproductive) e.g. shoots and spikes, in case of small grain cereals, shoots and pods in case of grain legumes and tops and roots or beets (including crown) in case of sugar beet, etc. In any case the ultimate goal of these procedures is to obtain representative subsample harvested from greenhouse or field experiments for chemical analysis. Before harvesting an isotopic-aided experiment the method of sampling has to be selected. It should be based on the type of information required in relation to the objectives of the research and the availability of resources (staff, sample preparation equipment, analytical facilities, chemicals and supplies, etc.). 10 refs, 3 figs, 3 tabs

Effect of sample preparation techniques on the concentrations and distributions of elements in biological tissues using µSRXRF: a comparative study

International Nuclear Information System (INIS)

Al-Ebraheem, A; Dao, E; Desouza, E; McNeill, F E; Farquharson, M J; Li, C; Wainman, B C

2015-01-01

Routine tissue sample preparation using chemical fixatives is known to preserve the morphology of the tissue being studied. A competitive method, cryofixation followed by freeze drying, involves no chemical agents and maintains the biological function of the tissue. The possible effects of both sample preparation techniques in terms of the distribution of bio-metals (calcium (Ca), copper (Cu) zinc (Zn), and iron (Fe) specifically) in human skin tissue samples was investigated. Micro synchrotron radiation x-ray fluorescence (μSRXRF) was used to map bio-metal distribution in epidermal and dermal layers of human skin samples from various locations of the body that have been prepared using both techniques. For Ca, Cu and Zn, there were statistically significant differences between the epidermis and dermis using the freeze drying technique (p = 0.02, p < 0.01, and p < 0.01, respectively). Also using the formalin fixed, paraffin embedded technique the levels of Ca, Cu and Zn, were significantly different between the epidermis and dermis layers (p = 0.03, p < 0.01, and p < 0.01, respectively). However, the difference in levels of Fe between the epidermis and dermis was unclear and further analysis was required. The epidermis was further divided into two sub-layers, one mainly composed of the stratum corneum and the other deeper layer, the stratum basale. It was found that the difference between the distribution of Fe in the two epidermal layers using the freeze drying technique resulted in a statistically significant difference (p = 0.012). This same region also showed a difference in Fe using the formalin fixed, paraffin embedded technique (p < 0.01). The formalin fixed, paraffin embedded technique also showed a difference between the deeper epidermal layer and the dermis (p < 0.01). It can be concluded that studies involving Ca, Cu and Zn might show similar results using both sample preparation techniques, however studies involving Fe would need more

Fuel cell membrane preparation: effects of base polymer

Energy Technology Data Exchange (ETDEWEB)

Brack, H P; Scherer, G G [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

Radiation grafted films and membranes prepared from the partially fluorinated base copolymer poly(ethylene-alt-tetrafluoroethylene) or ETFE have better mechanical properties than those prepared from poly(tetrafluoroethylene-co-hexafluoropropylene) or FEP. The influence of the base copolymer film type on the grafting rate and yields is reported in the present investigation. An understanding of the effects of these parameters is important so that the grafting process can be carried out reproducibly in as short a time as possible. The grafting rate and yield as a function of the irradiation dose has been found to be much higher for the partially fluorinated base copolymer ETFE. (author) 2 figs., 1 tab., 5 refs.

Preparation of poly(ether ether ketone)-based polymer electrolytes for fuel cell membranes using grafting technique

International Nuclear Information System (INIS)

Hasegawa, Shin; Suzuki, Yasuyuki; Maekawa, Yasunari

2008-01-01

Poly(ether ether ketone) (PEEK)-based polymer electrolyte membranes (PEMs) was successfully prepared by radiation grafting of a styrene monomer into PEEK films and the consequent selective sulfonation of the grafting chains in the film state. Using milder sulfonation, the sulfonation reactions proceeded at the grafted chains in preference to the phenylene rings of PEEK main chains; as a result, the grafted films could successfully transform to a PEM with conductivity of more than 0.1 S/cm. The ion exchange capacity (IEC) and conductivity of the grafted PEEK electrolyte membranes were controlled to the ranges of 1.2-2.9 mmol/g and 0.03-0.18 S/cm by changing the grafting degree. It should be noted that this is the first example of directly transforming super-engineering plastic films into a PEM using radiation grafting

Preparation of redispersible liposomal dry powder using an ultrasonic spray freeze-drying technique for transdermal delivery of human epithelial growth factor.

Science.gov (United States)

Yin, Fei; Guo, Shiyan; Gan, Yong; Zhang, Xinxin

2014-01-01

In this work, an ultrasonic spray freeze-drying (USFD) technique was used to prepare a stable liposomal dry powder for transdermal delivery of recombinant human epithelial growth factor (rhEGF). Morphology, particle size, entrapment efficiency, in vitro release, and skin permeability were systematically compared between rhEGF liposomal dry powder prepared using USFD and that prepared using a conventional lyophilization process. Porous and spherical particles with high specific area were produced under USFD conditions. USFD effectively avoided formation of ice crystals, disruption of the bilayer structure, and drug leakage during the liposome drying process, and maintained the stability of the rhEGF liposomal formulation during storage. The reconstituted rhEGF liposomes prepared from USFD powder did not show significant changes in morphology, particle size, entrapment efficiency, or in vitro release characteristics compared with those of rhEGF liposomes before drying. Moreover, the rhEGF liposomal powder prepared with USFD exhibited excellent enhanced penetration in ex vivo mouse skin compared with that for powder prepared via conventional lyophilization. The results suggest that ultrasonic USFD is a promising technique for the production of stable protein-loaded liposomal dry powder for application to the skin.

Appropriate materials and preparation techniques for polycrystalline-thin-film thermophotovoltaic cells

Science.gov (United States)

Dhere, Neelkanth G.

1997-03-01

techniques have paved the way for obtaining epitaxial Hg1-xCdxTe thin films at substrate temperatures of ~180 °C with the desired crystalline perfection, stoichiometry, and doping without the necessity of further annealing for improving either the crystalline quality or dopant activity. Retaining larger mercury proportions during annealing would require heated enclosures as in isothermal VPE, hot-wall technique, vacuum evaporation, hot-wall MOCVD, or close-space sublimation. Pb1-xCdxTe thin films can be prepared by magnetron sputtering from cooled Pb1-xCdxTe targets on heated substrates. Hot-wall technique is suitable for the deposition of Pb1-xCdxTe thin films. Hg1-xCdxTe and Pb1-xCdxTe TPV cells will benefit from the substantial work on CdTe thin film solar cells. The paper reviews work on thin films of ternary and pseudoternary compounds of interest for TPV conversion and methods of their preparation with a view to choosing the appropriate materials and fabrication techniques for polycrystalline-thin-film TPV cells.

Case-based reasoning diagnostic technique based on multi-attribute similarity

Energy Technology Data Exchange (ETDEWEB)

Makoto, Takahashi [Tohoku University, Miyagi (Japan); Akio, Gofuku [Okayama University, Okayamaa (Japan)

2014-08-15

Case-based diagnostic technique has been developed based on the multi-attribute similarity. Specific feature of the developed system is to use multiple attributes of process signals for similarity evaluation to retrieve a similar case stored in a case base. The present technique has been applied to the measurement data from Monju with some simulated anomalies. The results of numerical experiments showed that the present technique can be utilizes as one of the methods for a hybrid-type diagnosis system.

Microtomography-based comparison of reciprocating single-file F2 ProTaper technique versus rotary full sequence

OpenAIRE

Paqué, F; Zehnder, Matthias; De-Deus, G

2011-01-01

Introduction A preparation technique with only 1 single instrument was proposed on the basis of the reciprocating movement of the F2 ProTaper instrument. The present study was designed to quantitatively assess canal preparation outcomes achieved by this technique. Methods Twenty-five extracted human mandibular first molars with 2 separate mesial root canals were selected. Canals were randomly assigned to 1 of the 2 experimental groups: group 1, rotary conventional preparation by us...

Tensile-Creep Test Specimen Preparation Practices of Surface Support Liners

Science.gov (United States)

Guner, Dogukan; Ozturk, Hasan

2017-12-01

Ground support has always been considered as a challenging issue in all underground operations. Many forms of support systems and supporting techniques are available in the mining/tunnelling industry. In the last two decades, a new polymer based material, Thin Spray-on Liner (TSL), has attained a place in the market as an alternative to the current areal ground support systems. Although TSL provides numerous merits and has different application purposes, the knowledge on mechanical properties and performance of this material is still limited. In laboratory studies, since tensile rupture is the most commonly observed failure mechanism in field applications, researchers have generally studied the tensile testing of TSLs with modification of American Society for Testing and Materials (ASTM) D-638 standards. For tensile creep testing, specimen preparation process also follows the ASTM standards. Two different specimen dimension types (Type I, Type IV) are widely preferred in TSL tensile testing that conform to the related standards. Moreover, molding and die cutting are commonly used specimen preparation techniques. In literature, there is a great variability of test results due to the difference in specimen preparation techniques and practices. In this study, a ductile TSL product was tested in order to investigate the effect of both specimen preparation techniques and specimen dimensions under 7-day curing time. As a result, ultimate tensile strength, tensile yield strength, tensile modulus, and elongation at break values were obtained for 4 different test series. It is concluded that Type IV specimens have higher strength values compared to Type I specimens and moulded specimens have lower results than that of prepared by using die cutter. Moreover, specimens prepared by molding techniques have scattered test results. Type IV specimens prepared by die cutter technique are suggested for preparation of tensile test and Type I specimens prepared by die cutter technique

A study of preparation techniques and properties of bulk nanocomposites based on aqueous albumin dispersion

Science.gov (United States)

Gerasimenko, A. Yu.; Dedkova, A. A.; Ichkitidze, L. P.; Podgaetskii, V. M.; Selishchev, S. V.

2013-08-01

Bulk nanocomposites prepared from an aqueous albumin dispersion with carbon nanotubes by removing the liquid component from the dispersion have been investigated. The composites were obtained by thermostating and exposure to LED and IR diode laser radiation. The nanocomposites obtained under laser irradiation retain their shape and properties for several years, in contrast to the composites fabricated in different ways (which decompose into small fragments immediately after preparation). The low density of the composites under study (˜1200 kg/m3), which is close to the density of water, is due to their high porosity. The hardness of stable nanocomposites (˜300 MPa) was found to be at the same level as the hardness of polymethylmethacrylate, aluminum, and iron and close to the hardness of human bone tissue. The cluster quasiordering of the inner structure of nanocomposites revealed by atomic force microscopy indicates the possibility of forming a bulk nanotube framework in them, which can be caused by the effect of the electric field of laser radiation and ensure their stability and hardness. The presence of a framework in nanocomposites provides conditions for self-assembly of biological tissues and makes it possible to apply laser-prepared nanocomposites as a component of surgical implants.

Preparation of Acrylamide-based Anionic Polyelectrolytes for Soil Establishment

Directory of Open Access Journals (Sweden)

Ahmad Rabiee

2012-12-01

Full Text Available Synthetic water soluble acrylamide-based polymers have wide range of ap-plications  in  the  feld  of  soil  establishment  and  non-desertifcation.  In  this research, the acrylamide-based anionic polyelectrolytes were prepared by  solution polymerization. The polymerization was carried out using AIBN as a radical initiator and at different degrees of anionic charges ranging between 10% and 30% using sodium hydroxide as hydrolyzing agents. The chemical structure of the  synthetic polymers was studied and confrmed by FTIR technique. The charge density on polymer backbone was determined by titration method. The rheological behavior of polymer solutions was evaluated by Brookfeld viscometer. The results show that the viscosity decreases with increasing the shear rate of solutions. Molecular weights of samples were measured by laser light scattering analyzer. The morphology of the polymer was studied by SEM and the EDX was used for elemental analysis determination. The anionic polymers with 10-30% negative charges were mixed with clay in order to evaluate the soil establishment. The results show that an anionic polyelectro-lyte can make soil particles more cohesive and improve soil physical properties.

In vitro biological characterization of macroporous 3D Bonelike structures prepared through a 3D machining technique

International Nuclear Information System (INIS)

Laranjeira, M.S.; Dias, A.G.; Santos, J.D.; Fernandes, M.H.

2009-01-01

3D bioactive macroporous structures were prepared using a 3D machining technique. A virtual 3D structure model was created and a computer numerically controlled (CNC) milling device machined Bonelike samples. The resulting structures showed a reproducible macroporosity and interconnective structure. Macropores size after sintering was approximately 2000 μm. In vitro testing using human bone marrow stroma showed that cells were able to adhere and proliferate on 3D structures surface and migrate into all macropore channels. In addition, these cells were able to differentiate, since mineralized globular structures associated with cell layer were identified. Results obtained showed that 3D structures of Bonelike successfully allow cell migration into all macropores, and allow human bone marrow stromal cells to proliferate and differentiate. This innovative technique may be considered as a step-forward preparation for 3D interconnective macroporous structures that allow bone ingrowth while maintaining mechanical integrity.

Bacteriophage-based Probiotic Preparation for Managing Shigella Infections

Science.gov (United States)

2015-04-16

The preparation (designated “ShigActive”) is a bacteriophage cocktail that specifically targets Shigella spp. (significant diarrhea-causing pathogens...phages lytic for Shigella , and we have developed a murine model in which the in vivo efficacy of our 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND...10-Apr-2013 Approved for Public Release; Distribution Unlimited Final Report: Bacteriophage-based Probiotic Preparation for Managing Shigella

Uranium exploration data and techniques applied to the preparation of radioelement maps. Proceedings of a technical committee meeting

International Nuclear Information System (INIS)

1997-11-01

The report reviews the advantage and pitfalls of using uranium exploration data and techniques as well as other methods for the preparation of radioelement and radon maps for baseline information in environmental studies and monitoring

Comparison of optical properties of Eu3+ ions in the silica gel glasses obtained by different preparation techniques

International Nuclear Information System (INIS)

Legendziewicz, J.; Sokolnicki, J.; Keller, B.; Borzechowska, M.; Strek, W.

1996-01-01

Silica-gel glasses doped with Eu 3+ ions were obtained by different preparation techniques. The absorption, emission and excitation spectra of the obtained glasses were measured in the range of 77-300 K. The energy levels diagrams of Eu 3+ ions were derived. An intensity analysis of f-f transitions was performed. In particular, polymeric structure behaviour of europium compounds entrapped in silica gel glasses was temperature controlled during the preparation of glasses. Their optical properties were investigated. (author)

Preparation of Dimethylaminoethylmethacrylate Grafted Polymeric Adsorbent by Using Radiation-Induced Grafting Technique for Removal of Anions

International Nuclear Information System (INIS)

Kavakli, P. A.

2006-01-01

The development of efficient separation and purification techniques is very important from industrial, environmental and economic points of view. Polymeric materials having polyfunctional groups such as carboxylic, amide, nitrile, iminodiacetic acid, amidoxime, and ammonium groups, etc., not only possess good hydrophilic properties, but also have good ion exchange properties which make them suitable for metal recovery from aqueous solutions. Radiation induced grafting is a powerful technique capable of controlling the introduction of various functional groups to the polymeric materials, keeping the original properties and especially the mechanical strength of the base material, and thus, allowing the synthesis of more stable polymeric adsorbents. The main objective of this study was to develop special polymeric adsorbents to remove NOx and PO 4 anions from aqueous systems. For this purpose, a novel nonwoven fabric was prepared by radiation-induced graft polymerization of imethylaminoethylmethacrylate (DMAEMA) onto polypropylene coated polyethylene nonwoven fabric. The trunk polymer was irradiated by electron beam at a voltage of 2 MeV and a current of 3 mA in a nitrogen atmosphere at dry-ice temperature at different doses. The degree of grafting was determined as a function of the total dose, monomer concentration, temperature, and reaction time. It was found that the degree of grafting of grafted polymer was greatly affected by reaction conditions. Grafting conditions were optimized, and about 150 % degree of grafting samples was used for further experiments. DMAEMA grafted polymer was later protonated by using acid solution to prepare adsorbent for the removal of anions. Adsorption experiments were performed in column mode for removal of phosphate. Approximately 2000 bed volumes of phosphate-free water can be produced from 10 ppb phosphate solution at high space velocity

Deposition techniques for the preparation of thin film nuclear targets

International Nuclear Information System (INIS)

Muggleton, A.H.F.

1987-07-01

This review commences with a brief description of the basic principles that regulate vacuum evaporation and the physical processes involved in thin film formation, followed by a description of the experimental methods used. The principle methods of heating the evaporant are detailed and the means of measuring and controlling the film thickness are elucidated. Types of thin film nuclear targets are considered and various film release agents are listed. Thin film nuclear target behaviour under ion-bombardment is described and the dependence of nuclear experimental results upon target thickness and uniformity is outlined. Special problems associated with preparing suitable targets for lifetime measurements are discussed. The causes of stripper-foil thickening and breaking under heavy-ion bombardment are considered. A comparison is made between foils manufactured by a glow discharge process and those produced by vacuum sublimation. Consideration is given to the methods of carbon stripper-foil manufacture and to the characteristics of stripper-foil lifetimes are considered. Techniques are described that have been developed for the fabrication of special targets, both from natural and isotopically enriched material, and also of elements that are either chemically unstable, or thermally unstable under irradiation. The reduction of metal oxides by the use of hydrogen or by utilising a metallothermic technique, and the simultaneous evaporation of reduced rare earth elements is described. A comprehensive list of the common targets is presented

Preparation and characterization of zinc sulphide nanocomposites based on acrylonitrile butadiene rubber

Science.gov (United States)

Ramesan, M. T.; Nihmath, A.; Francis, Joseph

2013-06-01

Rubber composite based on acrylonitrile butadiene rubber (NBR) reinforced with nano zinc sulphide (ZnS) have been prepared via vulcanization process and characterized by several techniques. Processing characteristics such as scorch time, optimum cure time decreases with increase in concentration of nano filler in acrylonitrile butadiene rubber. Mechanical properties such as tensile and tear strength increases with increase in concentration of nano filler up to 7 phr of loading thereafter the value decreases, whereas hardness, and flame resistance increases with the dosage of fillers. These enhanced properties are due to the homogenous dispersion of nano fillers in NBR matrix, which is evidenced from the structure that evaluated using X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Composite Techniques Based Color Image Compression

Directory of Open Access Journals (Sweden)

Zainab Ibrahim Abood

2017-03-01

Full Text Available Compression for color image is now necessary for transmission and storage in the data bases since the color gives a pleasing nature and natural for any object, so three composite techniques based color image compression is implemented to achieve image with high compression, no loss in original image, better performance and good image quality. These techniques are composite stationary wavelet technique (S, composite wavelet technique (W and composite multi-wavelet technique (M. For the high energy sub-band of the 3rd level of each composite transform in each composite technique, the compression parameters are calculated. The best composite transform among the 27 types is the three levels of multi-wavelet transform (MMM in M technique which has the highest values of energy (En and compression ratio (CR and least values of bit per pixel (bpp, time (T and rate distortion R(D. Also the values of the compression parameters of the color image are nearly the same as the average values of the compression parameters of the three bands of the same image.

Effect of Formulation and Process Parameters on Chitosan Microparticles Prepared by an Emulsion Crosslinking Technique.

Science.gov (United States)

Rodriguez, Lidia B; Avalos, Abraham; Chiaia, Nicholas; Nadarajah, Arunan

2017-05-01

There are many studies about the synthesis of chitosan microparticles; however, most of them have very low production rate, have wide size distribution, are difficult to reproduce, and use harsh crosslinking agents. Uniform microparticles are necessary to obtain repeatable drug release behavior. The main focus of this investigation was to study the effect of the process and formulation parameters during the preparation of chitosan microparticles in order to produce particles with narrow size distribution. The technique evaluated during this study was emulsion crosslinking technique. Chitosan is a biocompatible and biodegradable material but lacks good mechanical properties; for that reason, chitosan was ionically crosslinked with sodium tripolyphosphate (TPP) at three different ratios (32, 64, and 100%). The model drug used was acetylsalicylic acid (ASA). During the preparation of the microparticles, chitosan was first mixed with ASA and then dispersed in oil containing an emulsifier. The evaporation of the solvents hardened the hydrophilic droplets forming microparticles with spherical shape. The process and formulation parameters were varied, and the microparticles were characterized by their morphology, particle size, drug loading efficiency, and drug release behavior. The higher drug loading efficiency was achieved by using 32% mass ratio of TPP to chitosan. The average microparticle size was 18.7 μm. The optimum formulation conditions to prepare uniform spherical microparticles were determined and represented by a region in a triangular phase diagram. The drug release analyses were evaluated in phosphate buffer solution at pH 7.4 and were mainly completed at 24 h.

Coacervative extraction as a green technique for sample preparation for the analysis of organic compounds.

Science.gov (United States)

Melnyk, A; Wolska, L; Namieśnik, J

2014-04-25

One of the present trends in analytical chemistry is miniaturization, which is one of the methods of green analytical chemistry application. A particular emphasis is placed on the elimination of the use of large amounts of organic solvents which are toxic and harmful to the environment, maintaining high efficiency of the extraction process, high recovery values and low values of quantification (LOQ) and detection (LOD) limits. These requirements are fulfilled by coacervative extraction (CAE) technique. In this review, theoretical aspects of the coacervation process are presented along with environmental and bioanalytical applications of this technique, its advantages, limitations and competitiveness with other techniques. Due to its simplicity and rapidity, CAE is an excellent alternative for currently practiced procedures of sample preparation for the analysis of organic compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

Study of microstructure and electrical properties of bulk YBCO prepared by melt textured growth technique

International Nuclear Information System (INIS)

Gonal, M. R.; Krishnan, Madangopal; Tewari, R.; Tyagi, A. K.; Gyore, A.; Vajda, I.

2015-01-01

Bulk YBCO components were prepared using Melt Texture Growth (MTG) technique. Components were fabricated using MTG by addition of Y 2 BaCuO 5 (Y211) and Ag to YBCO, which leads to improved grain size without affecting superconducting properties. Green compacts prepared by cold isostatic pressing were pre-sintered at 930°C before subjecting melt texturing. Cooling rates lower than 1 °C.h −1 was used, in between (peritectic) temperature of about 995 and 1025°C, to obtain large grained components. Microstructure studies in details were carried out by Scanning Electron Microscope (SEM), Electron Probe Micro Analysis (EPMA), Orientation Imaging Microscope (OIM) and TEM correlated with electrical properties like Critical current density (J c )

Preparation and characterization of titania based nanowires

International Nuclear Information System (INIS)

Stengl, Vaclav; Bakardjieva, Snejana; Murafa, Natalie; Vecernikova, Eva; Subrt, Jan; Balek, Vladimir

2007-01-01

A new method for preparation of titania nanowires with diameter around 10 nm and length up to 2-3 μm is described. The precursor was prepared from sodium titanate by adding ethylene glycole (EG) and heating at temperature of 198 deg. C for 6 h under reflux. The sodium titanate glycolate formed by this way aggregated into 1D nanostructures and was subsequently transformed into titania glycolate during a chemical treatment with 98% sulfuric acid. Titania nanowires with variable amount of anatase and rutile were prepared by heating to temperatures in the range 350-1000 deg. C. The precursor as well as titania based samples were characterized by X-ray diffraction, Infrared spectroscopy, Scanning electron microscopy, High resolution transmission microscopy, Thermogravimetry, Differential thermal analysis, Evolved gas analysis and Emanation thermal analysis. The nitrogen adsorption/desorption was used for surface area and porosity determination. The photoactivity of the prepared titania samples was assessed by the photocatalytic decomposition of 4-chlorophenol in an aqueous slurry under UV irradiation of 365 nm wavelength

Use of the electrodeposition technique in the preparation of samples of 237Np and its determination by alpha spectrometry

International Nuclear Information System (INIS)

Mertzig, W.; Matsuda, H.T.; Araujo, B.F. de; Araujo, J.A. de.

1981-05-01

The electroplating technique to prepare 237 Np source and its determination by alpha spectrometry is presented. The samples were prepared using a lucite-eletrolitic cell manufactured at IPEN, specially to trace amounts of actinides. A polished brass disk coated with Ni film has been used as cathodo and a fixed Pt wire as anode. The electroplated samples were alpha counted using a surface barrier detector. The optimum conditions to obtain the quantitative deposition of 237 Np have been achieved by studying the effects of some parameters as current density, pH and concentration of eletrolitic solution and time of eletrodeposition, using a carrier technique. After preliminary purification, the method is applied to control trace amounts of 237 Np in the Purex process solutions. (Author) [pt

Array-based techniques for fingerprinting medicinal herbs

Directory of Open Access Journals (Sweden)

Xue Charlie

2011-05-01

Full Text Available Abstract Poor quality control of medicinal herbs has led to instances of toxicity, poisoning and even deaths. The fundamental step in quality control of herbal medicine is accurate identification of herbs. Array-based techniques have recently been adapted to authenticate or identify herbal plants. This article reviews the current array-based techniques, eg oligonucleotides microarrays, gene-based probe microarrays, Suppression Subtractive Hybridization (SSH-based arrays, Diversity Array Technology (DArT and Subtracted Diversity Array (SDA. We further compare these techniques according to important parameters such as markers, polymorphism rates, restriction enzymes and sample type. The applicability of the array-based methods for fingerprinting depends on the availability of genomics and genetics of the species to be fingerprinted. For the species with few genome sequence information but high polymorphism rates, SDA techniques are particularly recommended because they require less labour and lower material cost.

Uranium exploration data and techniques applied to the preparation of radioelement maps. Proceedings of a technical committee meeting

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-11-01

The report reviews the advantage and pitfalls of using uranium exploration data and techniques as well as other methods for the preparation of radioelement and radon maps for baseline information in environmental studies and monitoring. Refs, figs, tabs.

TiTaCN-Co cermets prepared by mechanochemical technique: microstructure and mechanical properties

OpenAIRE

Fides, Martin; Hvizdoš, P.; Balko, Ján; Chicardi, E.; Gotor, F.J.

2016-01-01

Microstructure and mechanical characterization of (Ti,Ta)(C,N)-Co based solid solution cermets prepared by two mechanochemical synthesis processes (one- and two-step milling) and a pressureless sintering in protective helium atmosphere. Materials with composition of TixTa1- xC0.5N0.5-20%Co with two different Ti/Ta ratios (x = 0.9 and x = 0.95) were developed to prepare four groups of experimental materials. Microstructures were observed using confocal microscopy and grain size was ev...

Study of electrodeposition technique to prepare alpha-counting plates of uranium 233

International Nuclear Information System (INIS)

Mertzig, W.

1979-01-01

The electrodeposition technique to prepare alpha-counting plates of 233 U for its determination is presented. To determine the optimum conditions for plating 233 U the effects of such parameters as current density, pH of eletrotype, salt concentration, time of electrolysis and distance electrodes were studied. A carrier method was developed to attain a quantitative electrodeposition of 233 U from aqueous solutions into alpha counting paltes. A single and incremental addition of natural uranium and thorium as carrier were studied. All samples were prepared using a electrodeposition cell manufactured at the IPEN, especially for use in electroplating tracer actinides. This cell is made of a metal-lucite to contain the electrolyte, which bottom is a polished brass disk coated with a Ni film serving as the cathode. A Pt wire anode is fixed on the top of the cell. The electroplated samples were alpha-counted using a surface barrier detector. A recovery of more than 99% was obtained in specific conditions. The plating procedure produced deposits which were firmly distributed over the plate area. The method was applied to determine tracer amounts of 233 U from oxalate and nitrate solutions coming from chemical processing irradiated thorium. (Author) [pt

Preparation and testing of plant seed meal-based wood adhesives.

Science.gov (United States)

He, Zhongqi; Chapital, Dorselyn C

2015-03-05

Recently, the interest in plant seed meal-based products as wood adhesives has steadily increased, as these plant raw materials are considered renewable and environment-friendly. These natural products may serve as alternatives to petroleum-based adhesives to ease environmental and sustainability concerns. This work demonstrates the preparation and testing of the plant seed-based wood adhesives using cottonseed and soy meal as raw materials. In addition to untreated meals, water washed meals and protein isolates are prepared and tested. Adhesive slurries are prepared by mixing a freeze-dried meal product with deionized water (3:25 w/w) for 2 hr. Each adhesive preparation is applied to one end of 2 wood veneer strips using a brush. The tacky adhesive coated areas of the wood veneer strips are lapped and glued by hot-pressing. Adhesive strength is reported as the shear strength of the bonded wood specimen at break. Water resistance of the adhesives is measured by the change in shear strength of the bonded wood specimens at break after water soaking. This protocol allows one to assess plant seed-based agricultural products as suitable candidates for substitution of synthetic-based wood adhesives. Adjustments to the adhesive formulation with or without additives and bonding conditions could optimize their adhesive properties for various practical applications.

Preparation of indium tin oxide anodes using energy filtrating technique for top-emitting organic light-emitting diode

Energy Technology Data Exchange (ETDEWEB)

Zhaoyong, Wang [School of Physical Engineering and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450052 (China); School of Mathematics and Physics, Henan Urban Construction University, Pingdingshan 467036 (China); Ning, Yao, E-mail: yaoning@zzu.edu.cn [School of Physical Engineering and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450052 (China); Changbao, Han; Xing, Hu [School of Physical Engineering and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450052 (China)

2014-01-01

Indium tin oxide (ITO) anodes were deposited by an improved magnetron sputtering technique (energy filtrating magnetron sputtering technique, EFMS) for top-emitting organic light-emitting diodes (TOLEDs). The phases, surface morphologies and optical properties were examined by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM) and spectroscopic ellipsometer. The sheet resistances were measured by the sheet resistance meter. The electrical properties were tested by the Hall measurement system. The electro-optic characteristics were examined by a special home-made measurement system. Results indicated that ITO anode deposited by EFMS had a more uniform and smoother surface with smaller grains. ITO film was prepared with the electrical property of the lowest resistivity (4.56 × 10{sup −4} Ω cm), highest carrier density (6.48 × 10{sup 20} cm{sup −3}) and highest carrier mobility (21.1 cm{sup 2}/V/s). The average transmissivity of the ITO film was 87.0% in the wavelength range of 400–800 nm. The TOLEDs based on this ITO anode had a lower turn-on voltage of 2 V (>0.02 mA/cm{sup 2}), higher current density of 58.4 mA/cm{sup 2} at 30 V, higher current efficiency of 1.374 cd/A and higher luminous efficiency of 0.175 lm/W. The possible mechanism of the technique was discussed in detail.

Sodium ion conducting polymer electrolyte membrane prepared by phase inversion technique

Science.gov (United States)

Harshlata, Mishra, Kuldeep; Rai, D. K.

2018-04-01

A mechanically stable porous polymer membrane of Poly(vinylidene fluoride-hexafluoropropylene) has been prepared by phase inversion technique using steam as a non-solvent. The membrane possesses semicrystalline network with enhanced amorphicity as observed by X-ray diffraction. The membrane has been soaked in an electrolyte solution of 0.5M NaPF6 in Ethylene Carbonate/Propylene Carbonate (1:1) to obtain the gel polymer electrolyte. The porosity and electrolyte uptake of the membrane have been found to be 67% and 220% respectively. The room temperature ionic conductivity of the membrane has been obtained as ˜ 0.3 mS cm-1. The conductivity follows Arrhenius behavior with temperature and gives activation energy as 0.8 eV. The membrane has been found to possess significantly large electrochemical stability window of 5.0 V.

Earth Science for Educators: Preparing 7-12 Teachers for Standards-based, Inquiry Instruction

Science.gov (United States)

Sloan, H.

2002-05-01

"Earth Science for Educators" is an innovative, standards-based, graduate level teacher education curriculum that presents science content and pedagogic technique in parallel. The curriculum calls upon the resources and expertise of the American Museum of Natural History (AMNH) to prepare novice New York City teachers for teaching Earth Science. One of the goals of teacher education is to assure and facilitate science education reform through preparation of K-12 teachers who understand and are able to implement standard-based instruction. Standards reflect not only the content knowledge students are expected to attain but also the science skills and dispositions towards science they are expected to develop. Melding a list of standards with a curriculum outline to create inquiry-based classroom instruction that reaches a very diverse population of learners is extremely challenging. "Earth Science for Educators" helps novice teachers make the link between standards and practice by constantly connecting standards with instruction they receive and activities they carry out. Development of critical thinking and enthusiasm for inquiry is encouraged through engaging experience and contact with scientists and their work. Teachers are taught Earth systems science content through modeling of a wide variety of instruction and assessment methods based upon authentic scientific inquiry and aimed at different learning styles. Use of fieldwork and informal settings, such as the Museum, familiarizes novice teachers with ways of drawing on community resources for content and instructional settings. Metacognitive reflection that articulates standards, practice, and the teachers' own learning experience help draw out teachers' insights into their students' learning. The innovation of bring science content together with teaching methods is key to preparing teachers for standards-based, inquiry instruction. This curriculum was successfully piloted with a group of 28 novice teachers as

Characterization of Pd catalyst-electrodes deposited on YSZ: Influence of the preparation technique and the presence of a ceria interlayer

Energy Technology Data Exchange (ETDEWEB)

Jimenez-Borja, Carmen, E-mail: Carmen.JBorja@uclm.es [Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad de Castilla-La Mancha. Avenida Camilo Jose Cela 12, 13071 Ciudad Real (Spain); Matei, Florina [Department of Petroleum Processing Engineering and Environmental Protection, Petroleum - Gas University of Ploiesti (Romania); Dorado, Fernando; Valverde, Jose Luis [Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad de Castilla-La Mancha. Avenida Camilo Jose Cela 12, 13071 Ciudad Real (Spain)

2012-11-15

Highlights: Black-Right-Pointing-Pointer Impregnation of palladium over YSZ led to more dispersed films. Black-Right-Pointing-Pointer XPS spectra indicated electron deficient Pd{sup 2+} species on the surface of palladium films. Black-Right-Pointing-Pointer Impregnated palladium films were more active than those prepared by paste deposition Black-Right-Pointing-Pointer The addition of a CeO{sub 2} interlayer enhanced the catalytic rate for the impregnated samples. - Abstract: Palladium catalyst-electrodes supported on Y{sub 2}O{sub 3}-stabilized-ZrO{sub 2} (YSZ) prepared either by paste deposition or wet impregnation technique were characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found a strong dependence of the catalytic film preparation technique as well as of the presence of a ceria interlayer between the palladium film and the solid electrolyte on the catalytic activity towards methane oxidation. Impregnated palladium films were found to be more active than films prepared by paste deposition. Besides, the addition of ceria allowed stabilizing the palladium active phase for methane oxidation.

Soil analysis. Modern instrumental technique

International Nuclear Information System (INIS)

Smith, K.A.

1993-01-01

This book covers traditional methods of analysis and specialist monographs on individual instrumental techniques, which are usually not written with soil or plant analysis specifically in mind. The principles of the techniques are combined with discussions of sample preparation and matrix problems, and critical reviews of applications in soil science and related disciplines. Individual chapters are processed separately for inclusion in the appropriate data bases

Preparation of a novel ferrofluidic photoresist for two-photon photopolymerization technique

International Nuclear Information System (INIS)

Tian Ye; Lu Dongxiao; Jiang Haobo; Lin Xiaomei

2012-01-01

We present a novel route for the preparation of ferrofluidic photoresist compatible with two-photon photopolymerization (TPP). To get a homogeneous ferrofluidic photoresit, the compatibility of photoresist and magnetic materials has been improved. Monodispersed Fe 3 O 4 nanoparticles synthesized via thermal decomposition of iron precursor were stabilized by 6-(methacryloyloxy) hexanoic acid (a kind of acrylate-based monomer). A ferrofluidic photoresist was prepared by doping the modified Fe 3 O 4 nanoparticles in acrylate-based resin. In this way, the dispersibility of nanoparticles in photoresist was enhanced significantly. As a representative example, a precise magnetic micron-sized spring was created. In the test of the magnetic response, the sensitivity of magnetic microspring was improved remarkably due to the optimization of the ferrofluidic photoresist. When the intensity of external magnetic field reached a value of 1500 Gs, the deformation rate of the microspring would get to 2.25, indicating the compatibility of the ferrofluidic photoresist in microfabrication. - Highlights: ► A novel ferrofluid photoresist was developed for TPP fabrication. ► A micrometer-sized magnetic spring was successfully created. ► Performance of microsprings was highly improved due to the optimization of nanoparticles.

Characterization of La2MoO6 prepared by the cation complexation technique

International Nuclear Information System (INIS)

Rocha, R.A.; Muccillo, E.N.S.

2005-01-01

The La 2 MoO 6 mixed oxide was prepared by the cation complexation technique using citric acid as complexant agent. The main purpose of this work was to obtain a mesoporous powder with relatively high specific surface area. The thermal decomposition behavior of the metal complex was studied by thermal analysis and Fourier transform infrared spectroscopy. A specific surface area value of ∼15 m 2 g -1 was obtained by nitrogen adsorption/desorption measurements. X-ray diffraction patterns of calcined mesoporous materials reveal that even though a low degree of crystallinity is attained, this phase may be obtained at low temperatures

Analytical techniques for the determination of radiochemical purity of radiopharmaceuticals prepared from kits

International Nuclear Information System (INIS)

McLean, J.R.; Rockwell, L.J.; Welsh, W.J.

1977-01-01

The evaluation of efficacy of commercially available kits used for the preparation of radiopharmaceuticals is one aspect of the Radiation Protection Bureau's radiopharmaceutical quality control program. This report describes some of the analytical methodology employed in the program. The techniques may be of interest to hospital radiopharmacy personnel as many of the tests can be performed rapidly and with a minimum of special equipment, thus enabling the confirmation of radiopharmaceutical purity prior to patient administration. Manufacturers of kits may also be interested in learning of the analytical methods used in the assessment of their products. (auth)

High Throughput Sample Preparation and Analysis for DNA Sequencing, PCR and Combinatorial Screening of Catalysis Based on Capillary Array Technique

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yonghua [Iowa State Univ., Ames, IA (United States)

2000-01-01

Sample preparation has been one of the major bottlenecks for many high throughput analyses. The purpose of this research was to develop new sample preparation and integration approach for DNA sequencing, PCR based DNA analysis and combinatorial screening of homogeneous catalysis based on multiplexed capillary electrophoresis with laser induced fluorescence or imaging UV absorption detection. The author first introduced a method to integrate the front-end tasks to DNA capillary-array sequencers. protocols for directly sequencing the plasmids from a single bacterial colony in fused-silica capillaries were developed. After the colony was picked, lysis was accomplished in situ in the plastic sample tube using either a thermocycler or heating block. Upon heating, the plasmids were released while chromsomal DNA and membrane proteins were denatured and precipitated to the bottom of the tube. After adding enzyme and Sanger reagents, the resulting solution was aspirated into the reaction capillaries by a syringe pump, and cycle sequencing was initiated. No deleterious effect upon the reaction efficiency, the on-line purification system, or the capillary electrophoresis separation was observed, even though the crude lysate was used as the template. Multiplexed on-line DNA sequencing data from 8 parallel channels allowed base calling up to 620 bp with an accuracy of 98%. The entire system can be automatically regenerated for repeated operation. For PCR based DNA analysis, they demonstrated that capillary electrophoresis with UV detection can be used for DNA analysis starting from clinical sample without purification. After PCR reaction using cheek cell, blood or HIV-1 gag DNA, the reaction mixtures was injected into the capillary either on-line or off-line by base stacking. The protocol was also applied to capillary array electrophoresis. The use of cheaper detection, and the elimination of purification of DNA sample before or after PCR reaction, will make this approach an

N-isopropylacrylamide-based fine-dispersed thermosensitive ferrogels obtained via in-situ technique.

Science.gov (United States)

Korotych, O; Samchenko, Yu; Boldeskul, I; Ulberg, Z; Zholobak, N; Sukhodub, L

2013-03-01

Thermosensitive hydrogels with magnetic properties (ferrogels) are very promising for medical application, first of all, for the design of targeted delivery systems with controlled release of drugs and for magnetic hyperthermia and chemotherapy treatment of cancer. These magnetic hydrogels could be obtained using diverse techniques: ex- and in-situ syntheses. The present work is devoted to the study of magnetite (Fe(3)O(4)) formation inside the nanoreactors of (co)polymeric hydrogels. Polymeric templates (hydrogel films and fine-dispersed hydrogels) used for obtaining ferrogels were based on acrylic monomers: thermosensitive N-isopropylacrylamide, and hydrophilic acrylamide. Covalent cross-linking was accomplished using bifunctional monomer N,N'-methylenebisacrylamide. Influence of hydrophilic-lipophilic balance of polymeric templates and concentration of iron cations on the magnetite formation were investigated along with the development of ferrogel preparation technique. Cytotoxicity, physical and chemical properties of obtained magnetic hydrogels have been studied in this work. Copyright © 2012 Elsevier B.V. All rights reserved.

Communication methods and production techniques in fixed prosthesis fabrication: a UK based survey. Part 2: Production techniques

Science.gov (United States)

Berry, J.; Nesbit, M.; Saberi, S.; Petridis, H.

2014-01-01

Aim The aim of this study was to identify the communication methods and production techniques used by dentists and dental technicians for the fabrication of fixed prostheses within the UK from the dental technicians' perspective. This second paper reports on the production techniques utilised. Materials and methods Seven hundred and eighty-two online questionnaires were distributed to the Dental Laboratories Association membership and included a broad range of topics, such as demographics, impression disinfection and suitability, and various production techniques. Settings were managed in order to ensure anonymity of respondents. Statistical analysis was undertaken to test the influence of various demographic variables such as the source of information, the location, and the size of the dental laboratory. Results The number of completed responses totalled 248 (32% response rate). Ninety percent of the respondents were based in England and the majority of dental laboratories were categorised as small sized (working with up to 25 dentists). Concerns were raised regarding inadequate disinfection protocols between dentists and dental laboratories and the poor quality of master impressions. Full arch plastic trays were the most popular impression tray used by dentists in the fabrication of crowns (61%) and bridgework (68%). The majority (89%) of jaw registration records were considered inaccurate. Forty-four percent of dental laboratories preferred using semi-adjustable articulators. Axial and occlusal under-preparation of abutment teeth was reported as an issue in about 25% of cases. Base metal alloy was the most (52%) commonly used alloy material. Metal-ceramic crowns were the most popular choice for anterior (69%) and posterior (70%) cases. The various factors considered did not have any statistically significant effect on the answers provided. The only notable exception was the fact that more methods of communicating the size and shape of crowns were utilised for

Laser-based surface preparation of composite laminates leads to improved electrodes for electrical measurements

KAUST Repository

Almuhammadi, Khaled; Selvakumaran, Lakshmi; Alfano, Marco; Yang, Yang; Bera, Tushar Kanti; Lubineau, Gilles

2015-01-01

Electrical impedance tomography (EIT) is a low-cost, fast and effective structural health monitoring technique that can be used on carbon fiber reinforced polymers (CFRP). Electrodes are a key component of any EIT system and as such they should feature low resistivity as well as high robustness and reproducibility. Surface preparation is required prior to bonding of electrodes. Currently this task is mostly carried out by traditional sanding. However this is a time consuming procedure which can also induce damage to surface fibers and lead to spurious electrode properties. Here we propose an alternative processing technique based on the use of pulsed laser irradiation. The processing parameters that result in selective removal of the electrically insulating resin with minimum surface fiber damage are identified. A quantitative analysis of the electrical contact resistance is presented and the results are compared with those obtained using sanding.

Laser-based surface preparation of composite laminates leads to improved electrodes for electrical measurements

KAUST Repository

Almuhammadi, Khaled

2015-10-19

Electrical impedance tomography (EIT) is a low-cost, fast and effective structural health monitoring technique that can be used on carbon fiber reinforced polymers (CFRP). Electrodes are a key component of any EIT system and as such they should feature low resistivity as well as high robustness and reproducibility. Surface preparation is required prior to bonding of electrodes. Currently this task is mostly carried out by traditional sanding. However this is a time consuming procedure which can also induce damage to surface fibers and lead to spurious electrode properties. Here we propose an alternative processing technique based on the use of pulsed laser irradiation. The processing parameters that result in selective removal of the electrically insulating resin with minimum surface fiber damage are identified. A quantitative analysis of the electrical contact resistance is presented and the results are compared with those obtained using sanding.

Sample preparation in alkaline media

International Nuclear Information System (INIS)

Nobrega, Joaquim A.; Santos, Mirian C.; Sousa, Rafael A. de; Cadore, Solange; Barnes, Ramon M.; Tatro, Mark

2006-01-01

The use of tetramethylammonium hydroxide, tertiary amines and strongly alkaline reagents for sample treatment involving extraction and digestion procedures is discussed in this review. The preparation of slurries is also discussed. Based on literature data, alkaline media offer a good alternative for sample preparation involving an appreciable group of analytes in different types of samples. These reagents are also successfully employed in tailored speciation procedures wherein there is a critical dependence on maintenance of chemical forms. The effects of these reagents on measurements performed using spectroanalytical techniques are discussed. Several undesirable effects on transport and atomization processes necessitate use of the method of standard additions to obtain accurate results. It is also evident that alkaline media can improve the performance of techniques such as inductively coupled plasma mass spectrometry and accessories, such as autosamplers coupled to graphite furnace atomic absorption spectrometers

Structure and stability of human hemoglobin microparticles prepared with a double emulsion technique.

Science.gov (United States)

Cedrati, N; Bonneaux, F; Labrude, P; Maincent, P

1997-09-01

Hemoglobin solutions can be used as blood substitutes but they present some disadvantages often due to their rapid removal from the bloodstream after injection. A possible way of overcoming this problem is to trap hemoglobin inside particles. This study deals with the preparation, structure and stability of poly(lactic acid) and ethylcellulose microparticles containing human hemoglobin obtained with a double emulsion technique. We investigated the manufacturing process of these particles in order to increase the encapsulation ratio of hemoglobin. For this purpose, some parameters involved in the procedure were optimized, such as hemoglobin concentration and duration of stirring: hemoglobin loading increases with its concentration in the preparation and well-defined stirring time avoids a leakage of hemoglobin. Hemoglobin concentration, surfactant concentration i.e. poly(vinylic alcohol), amounts of polymer and solvent (methylene chloride), duration and speed of stirring. The microparticles were prepared with satisfactory yields (60 to 73%). They were spherical and their mean size was lower than 200 microns. The functional properties of entrapped hemoglobin were studied. The encapsulation did not alter hemoglobin and the oxygen affinity of the hemoglobin remained unmodified (P50 about 13.9 mm Hg in a Bis-Tris buffer pH 7.4 at 37 degrees C). Moreover, only low levels of methemoglobin could be detected (less than 3%). Besides, about 90% of encapsulated hemoglobin could be released from microparticles, with a speed related to the internal structure of the particles. The prepared microparticles were stored during one month at +4 degrees C. No degradation of the particle structure occurred and the functional properties of hemoglobin were preserved. These particles could provide a potential source of oxygen in the field of biotechnologies but any application for a transfusional purpose would first require a drastic reduction in particle size.

Modified Unzipping Technique to Prepare Graphene Nano-Sheets

Science.gov (United States)

Al-Tamimi, B. H.; Farid, S. B. H.; Chyad, F. A.

2018-05-01

Graphene nano-sheets have been prepared via unzipping approach of multiwall carbon nanotubes (MWCNTs). The method includes two chemical-steps, in which a multi-parameter oxidation step is performed to achieve unzipping the carbon nanotubes. Then, a reduction step is carried out to achieve the final graphene nano-sheets. In the oxidation step, the oxidant material was minimized and balanced with longer curing time. This modification is made in order to reduce the oxygen-functional groups at the ends of graphene basal planes, which reduce its electrical conductivity. In addition, a similar adjustment is achieved in the reduction step, i.e. the consumed chemicals is reduced which make the overall process more economic and eco-friendly. The prepared nano-sheets were characterized by atomic force microscopy, scanning electron microscopy, and Raman spectroscopy. The average thickness of the prepared graphene was about 5.23 nm.

Influence of preparation technique of ceramic superconductors on structure, mechanical and electrical properties

International Nuclear Information System (INIS)

Tomandl, G.; Kohl, R.

1991-01-01

Sol-Gel-like preparation techniques using citrate-, citrate/ethylenglycol- as well as ethylhexanoate precursors and the addition of fluorine were tested with regard to homogeneity and properties of HTSC-ceramics. A few single- and polycrystalline materials were coated with YBaCuOxide- and Bi Sr Ca Cu Oxide-films using ethylhexanoate-precursors. Interdiffusion reactions were investigated affecting the electrical properties. The best results in YBaCuOxide system were obtained using polycrystalline magnesia and silver as substrate materials. Bulk ceramics with a high degree of orientation were fabricated by reaction sintering and simultaneous external pressure. (orig.) With 44 refs., 6 tabs., 81 figs [de

Sample Preparation for Mass Spectrometry Imaging of Plant Tissues: A Review

Science.gov (United States)

Dong, Yonghui; Li, Bin; Malitsky, Sergey; Rogachev, Ilana; Aharoni, Asaph; Kaftan, Filip; Svatoš, Aleš; Franceschi, Pietro

2016-01-01

Mass spectrometry imaging (MSI) is a mass spectrometry based molecular ion imaging technique. It provides the means for ascertaining the spatial distribution of a large variety of analytes directly on tissue sample surfaces without any labeling or staining agents. These advantages make it an attractive molecular histology tool in medical, pharmaceutical, and biological research. Likewise, MSI has started gaining popularity in plant sciences; yet, information regarding sample preparation methods for plant tissues is still limited. Sample preparation is a crucial step that is directly associated with the quality and authenticity of the imaging results, it therefore demands in-depth studies based on the characteristics of plant samples. In this review, a sample preparation pipeline is discussed in detail and illustrated through selected practical examples. In particular, special concerns regarding sample preparation for plant imaging are critically evaluated. Finally, the applications of MSI techniques in plants are reviewed according to different classes of plant metabolites. PMID:26904042

Sample Preparation for Mass Spectrometry Imaging of Plant Tissues: A Review.

Science.gov (United States)

Dong, Yonghui; Li, Bin; Malitsky, Sergey; Rogachev, Ilana; Aharoni, Asaph; Kaftan, Filip; Svatoš, Aleš; Franceschi, Pietro

2016-01-01

Mass spectrometry imaging (MSI) is a mass spectrometry based molecular ion imaging technique. It provides the means for ascertaining the spatial distribution of a large variety of analytes directly on tissue sample surfaces without any labeling or staining agents. These advantages make it an attractive molecular histology tool in medical, pharmaceutical, and biological research. Likewise, MSI has started gaining popularity in plant sciences; yet, information regarding sample preparation methods for plant tissues is still limited. Sample preparation is a crucial step that is directly associated with the quality and authenticity of the imaging results, it therefore demands in-depth studies based on the characteristics of plant samples. In this review, a sample preparation pipeline is discussed in detail and illustrated through selected practical examples. In particular, special concerns regarding sample preparation for plant imaging are critically evaluated. Finally, the applications of MSI techniques in plants are reviewed according to different classes of plant metabolites.

Characterizations on the microstructures of LiMn2O4 prepared by a simple soft-chemical technique

International Nuclear Information System (INIS)

Wei Yingjin; Kim, Kwang Bum; Chen Gang; Park, Chul W.

2008-01-01

LiMn 2 O 4 powders were prepared by a simple soft-chemical technique at different temperatures. X-ray diffraction and thermogravimetric analysis suggested that the material prepared at 800 deg. C was stoichiometric LiMn 2 O 4 , whereas those prepared at 600 and 700 deg. C were Li[Mn 0.77 3+ Mn 1.23 4+ ]O 4.115 and Li[Mn 0.85 3+ Mn 1.15 4+ ]O 4.075 . Several typical XRD peaks of the compounds were investigated with an aim to elucidate (i) the Li immigration to the 16d octahedral sites, (ii) the partial tetragonal phase transition of the material and (iii) the mean coherent domain size and microstrain. SEM study showed that the particle size of the materials increased with heating temperature. The activation energy for the material particle growth was determined as 30.4 kJ mol -1

Two different preparation techniques for trace element determination of single Daphnia specimen using total reflection x-ray fluorescence analysis (TXRF)

International Nuclear Information System (INIS)

Woelfl, S.; Mages, M.

2000-01-01

Bio accumulation gives first information about the bio-availability of elements in waters and becomes more and more important for the characterization of the water quality. The use of common analytical techniques like ICP-MS and AAS requires large quantities of biologic sample material. Single preparation for example of Daphnia, a common species for bio-test experiments, are hardly possible with these procedures. Therefore alternatively quantitative TXRF element determination of individually prepared Daphnia was developed. Two preparation techniques for single freshwater crustacean specimen from a eutrophic branch of the river Elbe in the 'Rothehorn Park', Magdeburg (Daphnia: dry weight: 10 - 50 μg individuum -1 ) had been tested: (1) Wet preparation: the single Daphnia specimen had been washed with 0.45 μm filtered lake water and put onto quartz sample carriers. After air drying, the body length were determined in order to calculate the dry weight according to previously established body lengths-dry weight relationships. (2) Dry preparation: after collection specimen were washed with 0.45 μm filtered lake water and frozen in liquid nitrogen. The individual lyophilisated dried Daphnia were weighted using an ultrafine micro-balance and put onto quartz sample carriers. After preparation, addition of some μl Gallium standard solution and air drying the individual Daphnia were digested at the quartz sample carriers with 10 μl HNO 3 on a hot plate and dried once more. Finally the element concentrations were determined using a EXTRA IIA total-reflection x-ray fluorescence spectrometer. As a result of these investigations we can conclude that both, the 'dry' and 'wet' preparation method can be used for the element determination in small single crustaceans using TXRF spectrometry. It seems that the 'dry' method yields more precise results, but the wet method is easier to handle in field when samples cannot be fixed with liquid nitrogen. (author)

Current transport and capacitance-voltage characteristics of an n-PbTe/p-GaP heterojunction prepared using the electron beam deposition technique

Science.gov (United States)

Nasr, Mahmoud; El Radaf, I. M.; Mansour, A. M.

2018-04-01

In this study, a crystalline n-PbTe/p-GaP heterojunction was fabricated using the electron beam deposition technique. The structural properties of the prepared heterojunction were examined by X-ray diffraction and scanning electron microscopy. The dark current-voltage characteristics of the heterojunction were investigated at different temperatures ranging from 298 to 398 K. The rectification factor, series resistance, shunt resistance, diode ideality factor, and effective barrier height (ϕb) were determined. The photovoltaic parameters were identified based on the current density-voltage characteristics under illumination. The capacitance-voltage characteristics showed that the junction was abrupt in nature.

Improved sample preparation and counting techniques for enhanced tritium measurement sensitivity

Science.gov (United States)

Moran, J.; Aalseth, C.; Bailey, V. L.; Mace, E. K.; Overman, C.; Seifert, A.; Wilcox Freeburg, E. D.

2015-12-01

Tritium (T) measurements offer insight to a wealth of environmental applications including hydrologic tracking, discerning ocean circulation patterns, and aging ice formations. However, the relatively short half-life of T (12.3 years) limits its effective age dating range. Compounding this limitation is the decrease in atmospheric T content by over two orders of magnitude (from 1000-2000 TU in 1962 to testing in the 1960's. We are developing sample preparation methods coupled to direct counting of T via ultra-low background proportional counters which, when combined, offer improved T measurement sensitivity (~4.5 mmoles of H2 equivalent) and will help expand the application of T age dating to smaller sample sizes linked to persistent environmental questions despite the limitations above. For instance, this approach can be used to T date ~ 2.2 mmoles of CH4 collected from sample-limited systems including microbial communities, soils, or subsurface aquifers and can be combined with radiocarbon dating to distinguish the methane's formation age from C age in a system. This approach can also expand investigations into soil organic C where the improved sensitivity will permit resolution of soil C into more descriptive fractions and provide direct assessments of the stability of specific classes of organic matter in soils environments. We are employing a multiple step sample preparation system whereby organic samples are first combusted with resulting CO2 and H2O being used as a feedstock to synthesize CH4. This CH4 is mixed with Ar and loaded directly into an ultra-low background proportional counter for measurement of T β decay in a shallow underground laboratory. Analysis of water samples requires only the addition of geologic CO2 feedstock with the sample for methane synthesis. The chemical nature of the preparation techniques enable high sample throughput with only the final measurement requiring T decay with total sample analysis time ranging from 2 -5 weeks

Preparation of manganese-based perovskite nanoparticles using a ...

Indian Academy of Sciences (India)

Preparation of manganese-based perovskite nanoparticles using a reverse microemulsion method: ... ted much attention in various fields of medicine and pharma- cology such as .... In addition, the SAR value of sample was calculated through ...

Effect of immediate and delayed post space preparation on the apical seal of root canals obturated with different sealers and techniques

Directory of Open Access Journals (Sweden)

Hikmet Aydemir

2009-12-01

Full Text Available During mechanical preparation of the post space, the root canal filling may be twisted or vibrated, depending on several factors associated with the preparation technique and quality of filling. OBJECTIVE: The purpose of this study was to investigate the effect of immediate and delayed post space preparation on the integrity of the apical seal. MATERIAL AND METHODS: Sixty-four extracted human incisors were biomechanically prepared using the step-back technique. Sixty roots were randomly assigned to 6 experimental groups of 10 teeth each and the remaining 4 roots served as positive and negative controls (n=2. The root canals in the different groups were obturated with cold lateral and warm vertical condensation of gutta-percha and one of two sealers (Sealapex and Diaket. Post space was prepared either individually or simultaneously. An insulated copper wire was cut into 10-cm-long pieces. In each canal, one piece was inserted to maintain contact with gutta-percha and extended to the outside as one of two working electrodes. A stainless steel wire with the same dimensions of those of the copper wire, used as the other working electrode, was immersed into the background electrolyte from the center of the bottle. The electrical current between standard and experimental electrodes in canals was measured over a period of 10 days applying a conductivity meter. The Kruskal-Wallis test (p=0.05 determined whether there was a significant difference in microleakage among the groups and the Mann-Whitney U test (p=0.01 was used for multiple comparison grouping variables. RESULTS: The results suggest that only the differences between the root canal filling techniques were statistically significant (p0.01. CONCLUSION: The quality of the root canal filling is important for the integrity of the apical seal.

Multi-element analysis of lubricant oil by WDXRF technique using thin-film sample preparation

International Nuclear Information System (INIS)

Scapin, M. A.; Salvador, V. L. R.; Lopes, C. D.; Sato, I. M.

2006-01-01

The quantitative analysis of the chemical elements in matrices like oils or gels represents a challenge for the analytical chemists. The classics methods or instrumental techniques such as atomic absorption spectrometry (AAS) and plasma optical emission spectrometry (ICP-OES) need chemical treatments, mainly sample dissolution and degradation processes. X-ray fluorescence technique allows a direct and multi-element analysis without previous sample treatments. In this work, a sensible method for the determination of elements Mg, Al, Si, P, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Sn, Ba and Pb in lubricating oil is presented. The x-ray fluorescence (WDXRF) technique using linear regression method and thin film sample preparation was used. The validation of the methodology (repeatability and accuracy) was obtained by the analysis of the standard reference materials SRM Alpha AESAR lot 703527D, applying the Chauvenet, Cochrane, ANOVA and Z-score statistical tests. The method presents a relative standard deviation lower than 10% for all the elements, except for Pb determination (RSD Pb 15%). The Z-score values for all the elements were in the range -2 < Z < 2, indicating a very good accuracy.(Full text)

Lithium carbonate tablets. Preparation techniques influence over active ingredient liberation

International Nuclear Information System (INIS)

Bueno, J.H.F.; Oliveira, A.G. de; Toledo Salgado, P.E. de

1989-01-01

Lithium carbonate tablets, prepared using wet and dry granulation, were assessed in vitro so as to determine the active ingredient dissolution. In this study, standardized formulations were used and developed with usual adjuvants (lactose - maize starch). Parallel to the dissolution testing. The influence of the preparation process over some physical characteristics (hardness, friability and disintegration) was also analysed. Although a better performance was observed of tables prepared using dry granulation, the authors concluded that the wet process is more suitable in preparing tables with the mentioned drug. (author)

Preparing for budget-based payment methodologies: global payment and episode-based payment.

Science.gov (United States)

Hudson, Mark E

2015-10-01

Use of budget-based payment methodologies (capitation and episode-based bundled payment) has been demonstrated to drive value in healthcare delivery. With a focus on high-volume, high-cost surgical procedures, inclusion of anaesthesiology services in these methodologies is likely. This review provides a summary of budget-based payment methodologies and practical information necessary for anaesthesiologists to prepare for participation in these programmes. Although few examples of anaesthesiologists' participation in these models exist, an understanding of the structure of these programmes and opportunities for participation are available. Prospective preparation in developing anaesthesiology-specific bundled payment profiles and early participation in pathway development associated with selected episodes of care are essential for successful participation as a gainsharing partner. With significant opportunity to contribute to care coordination and cost management, anaesthesiology can play an important role in budget-based payment programmes and should expect to participate as full gainsharing partners. Precise costing methodologies and accurate economic modelling, along with identification of quality management and cost control opportunities, will help identify participation opportunities and appropriate payment and gainsharing agreements. Anaesthesiology-specific examples with budget-based payment models are needed to help guide increased participation in these programmes.

Moving from Rule-based to Principle-based in Public Sector: Preparers' Perspective

OpenAIRE

Roshayani Arshad; Normah Omar; Siti Fatimah Awang

2013-01-01

The move from cash accounting to accrual accounting, or rule-based to principle-based accounting, by many governments is part of an ongoing efforts in promoting a more business-like and performance-focused public sector. Using questionnaire responses from preparers of financial statements of public universities in Malaysia, this study examines the implementation challenges and benefits of principle-based accounting. Results from these responses suggest that most respondents perceived signific...

Computer-aided preparation of specifications for radial fans at VEB Lufttechnische Anlagen Berlin

Energy Technology Data Exchange (ETDEWEB)

Kubis, R.; Kull, W.

1987-01-01

The specification details the scope of delivery for radial fans on a standard page and also serves the preparation for production. In the place of previous manual preparation, a computer-aided technique for the office computer is presented that provides the technical parameters from data files out of few input data to identify the fan type. The data files and evaluative programs are based on the software tool REDABAS and the SCP operating system. Using this technique it has been possible to cut considerably the preparation time for the incoming orders.

Base Oils Biodegradability Prediction with Data Mining Techniques

Directory of Open Access Journals (Sweden)

Malika Trabelsi

2010-02-01

Full Text Available In this paper, we apply various data mining techniques including continuous numeric and discrete classification prediction models of base oils biodegradability, with emphasis on improving prediction accuracy. The results show that highly biodegradable oils can be better predicted through numeric models. In contrast, classification models did not uncover a similar dichotomy. With the exception of Memory Based Reasoning and Decision Trees, tested classification techniques achieved high classification prediction. However, the technique of Decision Trees helped uncover the most significant predictors. A simple classification rule derived based on this predictor resulted in good classification accuracy. The application of this rule enables efficient classification of base oils into either low or high biodegradability classes with high accuracy. For the latter, a higher precision biodegradability prediction can be obtained using continuous modeling techniques.

Preparation of PZT thin films on YBCO electrodes by KrF excimer laser ablation technique

International Nuclear Information System (INIS)

Kurogi, H.; Yamagata, Y.; Ebihara, K.

1998-01-01

Pb(Zr X Ti 1-X )O 3 (PZT) films have excellent ferroelectric, optical, piezoelectric, and pyroelectric properties. We prepared PZT thin films by the excimer laser ablation technique. A pulsed KrF excimer laser (Lambda Physik LPX305icc, pulse duration of 25 ns, λ=248 nm, 850 mJ Max.) was used to ablate the bulk targets. We investigated the influence of bottom electrode materials on the characteristics of the PZT thin films prepared on Pt and YBCO underlayers. The X-ray diffraction (XRD) patterns showed that the PZT films prepared with a laser fluence of 2 Jcm -2 on YBCO/MgO(100) substrate at a wide temperature range of 550-680 C have a perovskite (001) structure. At the same laser fluence, the PZT films prepared on Pt/MgO(100) substrate have a perovskite (001) structure only at 650 C. The polarization-electric field (P-E) characteristics and fatigue properties of PZT thin films were measured by the Sawyer-Tower circuit. The remnant polarization and coercive field have been found to be P r =15 μC cm -2 , 30 μC cm -2 and E c =200 kV cm -1 , 100 kV cm -1 for Au/PZT/Pt/MgO and Au/PZT/YBCO/MgO correspondingly. The remnant polarization of Au/PZT/YBCO/MgO thin film was reduced to one-half after about 10 8 cycles of switching. (orig.)

Application of liquid-based cytology preparation in micronucleus assay of exfoliated buccal epithelial cells in road construction workers.

Science.gov (United States)

Arul, P

2017-01-01

Asphalts are bitumens that consist of complex of hydrocarbon mixtures and it is used mainly in road construction and maintenance. This study was undertaken to evaluate the micronucleus (MN) assay of exfoliated buccal epithelial cells in road construction workers using liquid-based cytology (LBC) preparation. Three different stains (May-Grunwald Giemsa, hematoxylin and eosin, and Papanicolaou) were used to evaluate the frequency of MN in exfoliated buccal epithelial of 100 participants (fifty road construction workers and fifty administrative staff) using LBC preparation. Statistical analysis was performed with Student's t-test, and Proad construction exhibit a higher frequency of MN in exfoliated buccal epithelial cells and they are under the significant risk of cytogenetic damage. LBC preparation has potential application for the evaluation of frequency of MN. This technique may be advocated in those who are occupationally exposed to potentially carcinogenic agents in view of improvement in the smear quality and visualization of cell morphology.

Studying the structural and optical properties of Zn O:Cu prepared by APCVD technique

International Nuclear Information System (INIS)

Manssor, M.

2012-01-01

Undoped and Cu-doped Zn O ant (3-9 wt.%) thin films have been prepared by APCVD technique on glass substrates at 500 degree.The structural and optical properties of these films were studied. The results of the structural tests showed that these films are of a polycrystalline hexagonal structure with a preferred orientation in the (002) direction, the optical properties included transmittance, energy gap, ob sorption coefficient, reflectance, refractive index and extinction coefficient, the energy gap values were found to decrease from (3.25 to 3.15 eV) and the average transmittance was found about (90%) in the visible region. (author).

Recent Application of Solid Phase Based Techniques for Extraction and Preconcentration of Cyanotoxins in Environmental Matrices.

Science.gov (United States)

Mashile, Geaneth Pertunia; Nomngongo, Philiswa N

2017-03-04

Cyanotoxins are toxic and are found in eutrophic, municipal, and residential water supplies. For this reason, their occurrence in drinking water systems has become a global concern. Therefore, monitoring, control, risk assessment, and prevention of these contaminants in the environmental bodies are important subjects associated with public health. Thus, rapid, sensitive, selective, simple, and accurate analytical methods for the identification and determination of cyanotoxins are required. In this paper, the sampling methodologies and applications of solid phase-based sample preparation methods for the determination of cyanotoxins in environmental matrices are reviewed. The sample preparation techniques mainly include solid phase micro-extraction (SPME), solid phase extraction (SPE), and solid phase adsorption toxin tracking technology (SPATT). In addition, advantages and disadvantages and future prospects of these methods have been discussed.

Humidity sensing properties of WO3 thick film resistor prepared by screen printing technique

International Nuclear Information System (INIS)

Garde, Arun S

2014-01-01

Highlights: • Polycrystalline WO 3 Thick films are fabricated by screen printing technique. • Monoclinic phases were the majority in formation of films. • The peak at 1643 cm −1 shows stretching vibrations attributed to W-OH of adsorbed H 2 O. • Absorption peaks in the range 879–650 cm −1 are attributed to the stretching W-O-W bonds. • Increase in resistance with decrease in RH when exposed to 20–100% RH. - Abstract: Thick films of tungsten oxide based were prepared using standard screen printing technique. To study the effect of temperature on the thick films were fired at different temperature for 30 min in air atmosphere. The WO 3 thick films were characterized with X-ray diffraction, scanning electron microscopy and EDAX for elemental analysis. The formation of mixed phases of the film together with majority of monoclinic phase was observed. IR spectra confirm the peak at 1643 cm −1 clearly shows stretching vibrations attributed to the W-OH bending vibration mode of the adsorbed water molecules. The absorption peaks in the range 879–650 cm −1 are attributed to the stretching W-O-W bonds (i.e. ν [W-O inter -W]). The peak located at 983 cm −1 belong to W=O terminal of cluster boundaries. A change in the resistance was observed with respect to the relative humidity when the WO 3 thick films were exposed to a wide humidity range of 20–100%. An increasing firing temperature of WO 3 film increases with the sensitivity. The parameters such as sensitivity and hysteresis of the WO 3 film sensors have been evaluated

Preparation of surface enhanced Raman substrate and its characterization

Science.gov (United States)

Liu, Y.; Wang, J. Y.; Wang, J. Q.

2017-10-01

Surface enhanced Raman spectroscopy (SERS) is a fast, convenient and highly sensitive detection technique, and preparing the good effect and repeatable substrate is the key to realize the trace amount and quantitative detection in the field of food safety detection. In this paper, a surface enhanced Raman substrate based on submicrometer silver particles structure was prepared by chemical deposition method, and characterized its structure and optical properties.

[Preparation of simulate craniocerebral models via three dimensional printing technique].

Science.gov (United States)

Lan, Q; Chen, A L; Zhang, T; Zhu, Q; Xu, T

2016-08-09

Three dimensional (3D) printing technique was used to prepare the simulate craniocerebral models, which were applied to preoperative planning and surgical simulation. The image data was collected from PACS system. Image data of skull bone, brain tissue and tumors, cerebral arteries and aneurysms, and functional regions and relative neural tracts of the brain were extracted from thin slice scan (slice thickness 0.5 mm) of computed tomography (CT), magnetic resonance imaging (MRI, slice thickness 1mm), computed tomography angiography (CTA), and functional magnetic resonance imaging (fMRI) data, respectively. MIMICS software was applied to reconstruct colored virtual models by identifying and differentiating tissues according to their gray scales. Then the colored virtual models were submitted to 3D printer which produced life-sized craniocerebral models for surgical planning and surgical simulation. 3D printing craniocerebral models allowed neurosurgeons to perform complex procedures in specific clinical cases though detailed surgical planning. It offered great convenience for evaluating the size of spatial fissure of sellar region before surgery, which helped to optimize surgical approach planning. These 3D models also provided detailed information about the location of aneurysms and their parent arteries, which helped surgeons to choose appropriate aneurismal clips, as well as perform surgical simulation. The models further gave clear indications of depth and extent of tumors and their relationship to eloquent cortical areas and adjacent neural tracts, which were able to avoid surgical damaging of important neural structures. As a novel and promising technique, the application of 3D printing craniocerebral models could improve the surgical planning by converting virtual visualization into real life-sized models.It also contributes to functional anatomy study.

Synthesis, structural investigation and magnetic properties of Zn2+ substituted cobalt ferrite nanoparticles prepared by the sol–gel auto-combustion technique

International Nuclear Information System (INIS)

Raut, A.V.; Barkule, R.S.; Shengule, D.R.; Jadhav, K.M.

2014-01-01

Structural morphology and magnetic properties of the Co 1−x Zn x Fe 2 O 4 (0.0≤x≥1.0) spinel ferrite system synthesized by the sol–gel auto-combustion technique using nitrates of respective metal ions have been studied. The ratio of metal nitrates to citric acid was taken at 1:3. The as prepared powder of cobalt zinc ferrite was sintered at 600 °C for 12 h after TG/DTA thermal studies. Compositional stoichiometry was confirmed by energy dispersive analysis of the X-ray (EDAX) technique. Single phase cubic spinel structure of Co–Zn nanoparticles was confirmed by XRD data. The average crystallite size (t), lattice constant (a) and other structural parameters of zinc substituted cobalt ferrite nanoparticles were calculated from XRD followed by SEM and FTIR. It is observed that the sol–gel auto-combustion technique has many advantages for the synthesis of technologically applicable Co–Zn ferrite nanoparticles. The present investigation clearly shows the effect of the synthesis method and possible relation between magnetic properties and microstructure of the prepared samples. Increase in nonmagnetic Zn 2+ content in cobalt ferrite nanoparticles is followed by decrease in n B , M s and other magnetic parameters. Squareness ratio for the Co-ferrite was 1.096 at room temperature. - Highlights: • Co–Zn nanoparticles are prepared by sol–gel auto-combustion method. • Structural properties were characterized by XRD, SEM, and FTIR. • Compositional stoichiometry was confirmed by EDAX analysis. • Magnetic parameters were measured by the pulse field hysteresis loop technique

A Novel FCC Catalyst Based on a Porous Composite Material Synthesized via an In Situ Technique

Directory of Open Access Journals (Sweden)

Shu-Qin Zheng

2015-11-01

Full Text Available To overcome diffusion limitations and improve transport in microporous zeolite, the materials with a wide-pore structure have been developed. In this paper, composite microspheres with hierarchical porous structure were synthesized by an in situ technique using sepiolite, kaolin and pseudoboehmite as raw material. A novel fluid catalytic cracking (FCC catalyst for maximizing light oil yield was prepared based on the composite materials. The catalyst was characterized by XRD, FT-IR, SEM, nitrogen adsorption-desorption techniques and tested in a bench FCC unit. The results indicated that the catalyst had more meso- and macropores and more acid sites than the reference catalyst, and thus can increase light oil yield by 1.31 %, while exhibiting better gasoline and coke selectivity.

Techniques for preparation prior to embryo transfer

NARCIS (Netherlands)

Derks, Roos S.; Farquhar, Cindy; Mol, Ben Willem J.; Buckingham, Karen; Heineman, Maas Jan

2009-01-01

BACKGROUND: Embryo transfer (ET) is the final and most vulnerable step in in vitro fertilisation (IVF) treatment. Pregnancy rates after ET may be influenced by several factors including cervical preparation, the performance of a dummy or mock transfer, the choice of catheter, the use of ultrasound

[INDENA SPA company's patent portfolio of Ginkgo biloba preparation].

Science.gov (United States)

Wang, Nan; Guo, Kai; Cheng, Xin-min; Liu, Wei

2015-10-01

INDENA SPA Company in Italy is a multi-national company that produces and sells plant extracts. Based on its own re- search advantages in the field of Ginkgo biloba preparation, the company protects its own products market effectively through building patent portfolio around the patents of its opponent. Based on the multi-angle analysis for patent portfolio of G. biloba preparation from the aspects of application time, legal status, technical development route, and patent portfolio layout, this article provides technical reference on research and development of G. biloba preparation, and the author suggest that Chinese applicants learn techniques and layout experiences of other patents fully to enhance the level of research and patent protection level.

ZnO and copper indium chalcogenide heterojunctions prepared by inexpensive methods

International Nuclear Information System (INIS)

Berruet, M.; Di Iorio, Y.; Troviano, M.; Vázquez, M.

2014-01-01

Solution-based techniques were used to prepare ZnO/CuIn(Se, S) 2 heterojunctions that serve as solar cell prototypes. A duplex layer of ZnO (compact + porous) was electrodeposited. Chalcogenide thin films were deposited using successive ionic layer adsorption and reaction method (SILAR). By subsequent thermal treatments in two different atmospheres, CuInSe 2 (CISe) and CuInSe 2−x S x (CISeS) were obtained. The composition and morphology of the annealed films were characterized by GXRD, micro-Raman spectroscopy and SEM. Devices prepared with CISe and CISeS show a clear photo-response. The introduction of a buffer layer of TiO 2 into the ZnO/chalcogenide interface was necessary to detect photocurrent. The presence of CISeS improves the response of the cell, with higher values of short circuit current density, open circuit potential and fill factor. These promising results show that it is possible to prepare photovoltaic heterojunctions by depositing chalcogenides onto porous ZnO substrates using low-cost solution-based techniques. - Highlights: • Heterojunctions that serve as solar cell prototypes were prepared using solution-based techniques. • The devices comprised a double layer of ZnO and CuInSe 2 or CuInSe 0.4 S 1.6 . • A TiO 2 buffer layer in the ZnO/chalcogenide interface is necessary to detect photocurrent. • The incorporation of S improved the response of the photovoltaic heterojunction

Analytical techniques for the determination of radiochemical purity of radiopharmaceuticals prepared from kits. Pt. III

International Nuclear Information System (INIS)

McLean, J.R.; Rockwell, L.J.; Welsh, W.J.

1982-01-01

The evaluation of efficacy of commercially available kits used for the preparation of radiopharmaceuticals is one aspect of the Radiation Protection Bureau's radiopharmaceutical quality control program. This report describes some of the analytical methodology employed in the program. The techniques may be of interest to hospital radiopharmacy personnel since many of the tests can be performed rapidly and with a minimum of special equipment, thus enabling the confirmation of radiopharmaceutical purity prior to patient administration. Manufacturers of kits may also be interested in learning of the analytical methods used in the assessment of their products

Preparation of PZT thin films on YBCO electrodes by KrF excimer laser ablation technique

Energy Technology Data Exchange (ETDEWEB)

Kurogi, H; Yamagata, Y; Ebihara, K [Kumamoto Univ. (Japan). Dept. of Electr. Eng. and Comput. Sci.; Inoue, N [Kyushu Electric Power Co., Inc., Suizenji, 1-6-36, Kumamoto 862 (Japan)

1998-03-01

Pb(Zr{sub X}Ti{sub 1-X})O{sub 3} (PZT) films have excellent ferroelectric, optical, piezoelectric, and pyroelectric properties. We prepared PZT thin films by the excimer laser ablation technique. A pulsed KrF excimer laser (Lambda Physik LPX305icc, pulse duration of 25 ns, {lambda}=248 nm, 850 mJ Max.) was used to ablate the bulk targets. We investigated the influence of bottom electrode materials on the characteristics of the PZT thin films prepared on Pt and YBCO underlayers. The X-ray diffraction (XRD) patterns showed that the PZT films prepared with a laser fluence of 2 Jcm{sup -2} on YBCO/MgO(100) substrate at a wide temperature range of 550-680 C have a perovskite (001) structure. At the same laser fluence, the PZT films prepared on Pt/MgO(100) substrate have a perovskite (001) structure only at 650 C. The polarization-electric field (P-E) characteristics and fatigue properties of PZT thin films were measured by the Sawyer-Tower circuit. The remnant polarization and coercive field have been found to be P{sub r}=15 {mu}C cm{sup -2}, 30 {mu}C cm{sup -2} and E{sub c}=200 kV cm{sup -1}, 100 kV cm{sup -1} for Au/PZT/Pt/MgO and Au/PZT/YBCO/MgO correspondingly. The remnant polarization of Au/PZT/YBCO/MgO thin film was reduced to one-half after about 10{sup 8} cycles of switching. (orig.) 7 refs.

Preparation of polyhedral oligomeric silsesquioxane based imprinted monolith.

Science.gov (United States)

Li, Fang; Chen, Xiu-Xiu; Huang, Yan-Ping; Liu, Zhao-Sheng

2015-12-18

Polyhedral oligomeric silsesquioxane (POSS) was successfully applied, for the first time, to prepare imprinted monolithic column with high porosity and good permeability. The imprinted monolithic column was synthesized with a mixture of PSS-(1-Propylmethacrylate)-heptaisobutyl substituted (MA 0702), naproxon (template), 4-vinylpyridine, and ethylene glycol dimethacrylate, in ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4). The influence of synthesis parameters on the retention factor and imprinting effect, including the amount of MA 0702, the ratio of template to monomer, and the ratio of monomer to crosslinker, was investigated. The greatest imprinting factor on the imprinted monolithic column prepared with MA 0702 was 22, about 10 times higher than that prepared in absence of POSS. The comparisons between MIP monoliths synthesized with POSS and without POSS were made in terms of permeability, column efficiency, surface morphology and pore size distribution. In addition, thermodynamic and Van Deemter analysis were used to evaluate the POSS-based MIP monolith. Copyright © 2015 Elsevier B.V. All rights reserved.

A highly flexible polymerization technique to prepare fluorescent nanospheres for trace ammonia detection

International Nuclear Information System (INIS)

Waich, K.; Sandholzer, M.; Mayr, T.; Slugovc, C.; Klimant, I.

2010-01-01

The preparation of pH-sensitive nanospheres by emulsion polymerization for the detection of trace levels of ammonia is described. A fluorescent, polymerizable xanthene dye was copolymerized with styrene, crosslinkers and further copolymers aimed at enhancing the sensitivity to obtain materials for sensing of ammonia. A half-seeded technique was used to obtain stable emulsions of the monomers which were cured to obtain nanospheres with covalently attached active components. The nanospheres were embedded in a silicon matrix and the sensor films obtained were investigated regarding their response to ammonia at concentrations between 25 and 1,000 ppb. Sensors containing polystyrene nanospheres crosslinked with divinylbenzene showed the best performance in ammonia measurements exhibiting detection limits (LODs) of less than 25 ppb ammonia.

Effect of Various Sodium Chloride Mass Fractions on Wheat and Rye Bread Using Different Dough Preparation Techniques

Directory of Open Access Journals (Sweden)

Małgorzata Tańska

2016-01-01

Full Text Available This study assessed the selected properties of bread with reduced amount of sodium chloride. The bread was made from white and wholemeal wheat flour and rye flour. The dough was prepared using three techniques: with yeast, natural sourdough or starter sourdough. Sodium chloride was added to the dough at 0, 0.5, 1.0 and 1.5 % of the flour mass. The following bread properties were examined in the study: yield and volume of the loaf, moisture content, crumb firmness and porosity, and organoleptic properties. Reducing the mass fraction of added sodium chloride was not found to have considerable effect on bread yield, whereas it had a significant and variable effect on the loaf volume, and crumb firmness and porosity. Organoleptic assessment showed diverse effects of sodium chloride addition on sensory properties of bread, depending on the type of bread and the dough preparation method. Reduced mass fractions of sodium chloride changed the organoleptic properties of bread made with yeast and with starter sourdough to a greater extent than of bread prepared with natural sourdough.

Effect of Various Sodium Chloride Mass Fractions on Wheat and Rye Bread Using Different Dough Preparation Techniques

Science.gov (United States)

Tańska, Małgorzata; Rotkiewicz, Daniela; Piętak, Andrzej

2016-01-01

Summary This study assessed the selected properties of bread with reduced amount of sodium chloride. The bread was made from white and wholemeal wheat flour and rye flour. The dough was prepared using three techniques: with yeast, natural sourdough or starter sourdough. Sodium chloride was added to the dough at 0, 0.5, 1.0 and 1.5% of the flour mass. The following bread properties were examined in the study: yield and volume of the loaf, moisture content, crumb firmness and porosity, and organoleptic properties. Reducing the mass fraction of added sodium chloride was not found to have considerable effect on bread yield, whereas it had a significant and variable effect on the loaf volume, and crumb firmness and porosity. Organoleptic assessment showed diverse effects of sodium chloride addition on sensory properties of bread, depending on the type of bread and the dough preparation method. Reduced mass fractions of sodium chloride changed the organoleptic properties of bread made with yeast and with starter sourdough to a greater extent than of bread prepared with natural sourdough. PMID:27904407

PVA/CM-chitosan/honey hydrogels prepared by using the combined technique of irradiation followed by freeze-thawing

International Nuclear Information System (INIS)

Afshari, M.J.; Sheikh, N.; Afarideh, H.

2015-01-01

Hydrogels with three components, poly(vinyl alcohol) (PVA), carboxymethylate chitosan (CM-chitosan) and honey have been prepared by using radiation method and radiation followed by freeze-thawing cycles technique (combinational method). The solid concentration of the polymer solution is 15 wt% and the ratios of PVA/CM-chitosan/honey are 10/1.5/3.5, 10/2/3, 10/3/2, and 10/3.5/1.5. The applied irradiation doses are 25, 30 and 40 kGy. Various tests have been done to evaluate the hydrogel properties to produce materials to be used as wound dressing. The results show that combinational method improves the mechanical strength of hydrogels while it has no significant effect on the water evaporation rate of gels. The combinational method decreases the swelling of hydrogels significantly, albeit this parameter is still acceptable for wound dressing. Microbiological analyses show that the hydrogel prepared by both methods can protect the wound from Escherichia coli bacterial infection. The wound healing test shows the good performance of the gels in mice. - Highlights: • Hydrogels prepared by the combination of irradiation and freeze-thawing methods. • Hydrogels with improved mechanical strength prepared by the combinational method. • The prepared hydrogels had acceptable transparency and degree of swelling. • The water evaporation rates of these hydrogels were pretty low. • Presences of honey in the formulation of gels led to a higher tissue regeneration

[In vitro comparison of root canal preparation with step-back technique and GT rotary file--a nickel-titanium engine driven rotary instrument system].

Science.gov (United States)

Krajczár, Károly; Tóth, Vilmos; Nyárády, Zoltán; Szabó, Gyula

2005-06-01

The aim of the authors' study was to compare the remaining root canal wall thickness and the preparation time of root canals, prepared either with step-back technique, or with GT Rotary File, an engine driven nickel-titanium rotary instrument system. Twenty extracted molars were decoronated. Teeth were divided in two groups. In Group 1 root canals were prepared with step-back technique. In Group 2 GT Rotary File System was utilized. Preoperative vestibulo-oral X-ray pictures were taken from all teeth with radiovisiograph (RVG). The final preparations at the mesiobuccal canals (MB) were performed with size #30 and palatinal/distal canals with size #40 instruments. Postoperative RVG pictures were taken ensuring the preoperative positioning. The working time was measured in seconds during each preparation. The authors also assessed the remaining root canal wall thickness at 3, 6 and 9 mm from the radiological apex, comparing the width of the canal walls of the vestibulo-oral projections on pre- and postoperative RVG pictures both mesially and buccally. The ratios of the residual and preoperative root canal wall thickness were calculated and compared. The largest difference was found at the MB canals of the coronal and middle third level of the root, measured on the distal canal wall. The ratio of the remaining dentin wall thickness at the coronal and the middle level in the case of step-back preparation was 0.605 and 0.754, and 0.824 and 0.895 in the cases of GT files respectively. The preparation time needed for GT Rotary File System was altogether 68.7% (MB) and 52.5% (D/P canals) of corresponding step-back preparation times. The use of GT Rotary File with comparison of standard step-back method resulted in a shortened preparation time and excessive damage of the coronal part of the root canal could be avoided.

Application of rotating disk electrode technique for the preparation of Np, Pu and Am α-sources

International Nuclear Information System (INIS)

Tsoupko-Sitnikov, V.; Dayras, F.; Sanoit, J. de; Filossofov, D.

2000-01-01

Method of electrodeposition on rotating disk cathode (RDE) is applied for preparation of Np, Pu and Am α-standards. Phenomenon of critical current density is experimentally observed which is in perfect accord with Hansen's theory of electrodeposition. Influence of deposit calcination regime on quality of α-sources is studied, and comparison is made of uniformity of deposits obtained in various deposition systems. Standards with energy resolution better than 9 keV can be reproducibly obtained by optimized RDE electrodeposition technique

Anti-browning and barrier properties of edible coatings prepared with electrospraying

NARCIS (Netherlands)

Khan, M.K.I.; Cakmak, I.; Tavman, S.; Schutyser, M.A.I.; Schroen, C.G.P.H.

2014-01-01

Electrospraying is a novel technique for the application of coating to foods. In this study, thin lipid-based coatings were prepared by electrospraying on model surface and evaluated for their moisture barrier functionality. Sunflower oil and chocolate based coating materials were electrosprayed at

Experimental preparation and verification of quantum money

Science.gov (United States)

Guan, Jian-Yu; Arrazola, Juan Miguel; Amiri, Ryan; Zhang, Weijun; Li, Hao; You, Lixing; Wang, Zhen; Zhang, Qiang; Pan, Jian-Wei

2018-03-01

A quantum money scheme enables a trusted bank to provide untrusted users with verifiable quantum banknotes that cannot be forged. In this work, we report a proof-of-principle experimental demonstration of the preparation and verification of unforgeable quantum banknotes. We employ a security analysis that takes experimental imperfections fully into account. We measure a total of 3.6 ×106 states in one verification round, limiting the forging probability to 10-7 based on the security analysis. Our results demonstrate the feasibility of preparing and verifying quantum banknotes using currently available experimental techniques.

Photonic devices prepared by embossing in PDMS

Energy Technology Data Exchange (ETDEWEB)

Jandura, D., E-mail: jandura@fyzika.uniza.sk; Pudis, D.; Berezina, S.

2017-02-15

Highlights: • Fabrication technology of photonic devices based on embossing in PDMS is presented. • Analysis of morphological properties of prepared devices in PDMS by CLSM and AFM. • Spectral characterization of PDMS ring resonator proved the resonator functionality. - Abstract: In this paper, we present useful technique for fabrication of novel photonic devices created in the polydimethylsiloxane (PDMS). We use combination of direct laser writing in thin photoresist layer with embossing process of liquid PDMS. We prepared ring resonator and Mach-Zehnder interferometer in PDMS. The shape of prepared PDMS photonic devices was analyzed by confocal laser microscope and atomic force microscope. Optical characterization of these devices reveals extinction ratios of up to 20 dB.

Using the in situ lift-out technique to prepare TEM specimens on a single-beam FIB instrument

International Nuclear Information System (INIS)

Lekstrom, M; McLachlan, M A; Husain, S; McComb, D W; Shollock, B A

2008-01-01

Transmission electron microscope (TEM) specimens are today routinely prepared using focussed ion beam (FIB) instruments. Specifically, the lift-out method has become an increasingly popular technique and involves removing thin cross-sections from site-specific locations and transferring them to a TEM grid. This lift-out process can either be performed ex situ or in situ. The latter is mainly carried out on combined dual-beam FIB and scanning electron microscope (SEM) systems whereas conventional single-beam instruments often are limited to the traditional ex situ method. It is nevertheless desirable to enhance the capabilities of existing single-beam instruments to allow for in situ lift-out preparation to be performed since this technique offers a number of advantages over the older ex situ method. A single-beam FIB instrument was therefore modified to incorporate an in situ micromanipulator fitted with a tungsten needle, which can be attached to a cut-out FIB section using ion beam induced platinum deposition. This article addresses the issues of using an ion beam to monitor the in situ manipulation process as well as approaches that can be used to create stronger platinum welds between two objects, and finally, views on how to limit the extent of ion beam damage to the specimen surface.

A survey on OFDM channel estimation techniques based on denoising strategies

Directory of Open Access Journals (Sweden)

Pallaviram Sure

2017-04-01

Full Text Available Channel estimation forms the heart of any orthogonal frequency division multiplexing (OFDM based wireless communication receiver. Frequency domain pilot aided channel estimation techniques are either least squares (LS based or minimum mean square error (MMSE based. LS based techniques are computationally less complex. Unlike MMSE ones, they do not require a priori knowledge of channel statistics (KCS. However, the mean square error (MSE performance of the channel estimator incorporating MMSE based techniques is better compared to that obtained with the incorporation of LS based techniques. To enhance the MSE performance using LS based techniques, a variety of denoising strategies have been developed in the literature, which are applied on the LS estimated channel impulse response (CIR. The advantage of denoising threshold based LS techniques is that, they do not require KCS but still render near optimal MMSE performance similar to MMSE based techniques. In this paper, a detailed survey on various existing denoising strategies, with a comparative discussion of these strategies is presented.

Polycaprolactone Based Nanoparticles Loaded with Indomethacin for Anti-Inflammatory Therapy: From Preparation to Ex Vivo Study.

Science.gov (United States)

Badri, Waisudin; Miladi, Karim; Robin, Sophie; Viennet, Céline; Nazari, Qand Agha; Agusti, Géraldine; Fessi, Hatem; Elaissari, Abdelhamid

2017-09-01

This work focused on the preparation of polycaprolactone based nanoparticles containing indomethacin to provide topical analgesic and anti-inflammatory effect for symptomatic treatment of inflammatory diseases. Indomethacin loaded nanoparticles are prepared for topical application to decrease indomethacin side effects and administration frequency. Oppositely to already reported works, in this research non-invasive method has been used for the enhancement of indomethacin dermal drug penetration. Ex-vivo skin penetration study was carried out on fresh human skin. Nanoprecipitation was used to prepare nanoparticles. Nanoparticles were characterized using numerous techniques; dynamic light scattering, SEM, TEM, DSC and FTIR. Regarding ex-vivo skin penetration of nanoparticles, confocal laser scanning microscopy has been used. The results showed that NPs hydrodynamic size was between 220 to 245 nm and the zeta potential value ranges from -19 to -13 mV at pH 5 and 1 mM NaCl. The encapsulation efficiency was around 70% and the drug loading was about 14 to 17%. SEM and TEM images confirmed that the obtained nanoparticles were spherical with smooth surface. The prepared nanoparticles dispersions were stable for a period of 30 days under three temperatures of 4°C, 25°C and 40°C. In addition, CLSM images proved that obtained NPs can penetrate the skin as well. The prepared nanoparticles are submicron in nature, with good colloidal stability and penetrate the stratum corneum layer of the skin. This formulation potentiates IND skin penetration and as a promising strategy would be able to decline the side effects of IND.

Laser-based direct-write techniques for cell printing

Energy Technology Data Exchange (ETDEWEB)

Schiele, Nathan R; Corr, David T [Biomedical Engineering Department, Rensselaer Polytechnic Institute, Troy, NY (United States); Huang Yong [Department of Mechanical Engineering, Clemson University, Clemson, SC (United States); Raof, Nurazhani Abdul; Xie Yubing [College of Nanoscale Science and Engineering, University at Albany, SUNY, Albany, NY (United States); Chrisey, Douglas B, E-mail: schien@rpi.ed, E-mail: chrisd@rpi.ed [Material Science and Engineering Department, Rensselaer Polytechnic Institute, Troy, NY (United States)

2010-09-15

Fabrication of cellular constructs with spatial control of cell location ({+-}5 {mu}m) is essential to the advancement of a wide range of applications including tissue engineering, stem cell and cancer research. Precise cell placement, especially of multiple cell types in co- or multi-cultures and in three dimensions, can enable research possibilities otherwise impossible, such as the cell-by-cell assembly of complex cellular constructs. Laser-based direct writing, a printing technique first utilized in electronics applications, has been adapted to transfer living cells and other biological materials (e.g., enzymes, proteins and bioceramics). Many different cell types have been printed using laser-based direct writing, and this technique offers significant improvements when compared to conventional cell patterning techniques. The predominance of work to date has not been in application of the technique, but rather focused on demonstrating the ability of direct writing to pattern living cells, in a spatially precise manner, while maintaining cellular viability. This paper reviews laser-based additive direct-write techniques for cell printing, and the various cell types successfully laser direct-written that have applications in tissue engineering, stem cell and cancer research are highlighted. A particular focus is paid to process dynamics modeling and process-induced cell injury during laser-based cell direct writing. (topical review)

Laser-based direct-write techniques for cell printing

International Nuclear Information System (INIS)

Schiele, Nathan R; Corr, David T; Huang Yong; Raof, Nurazhani Abdul; Xie Yubing; Chrisey, Douglas B

2010-01-01

Fabrication of cellular constructs with spatial control of cell location (±5 μm) is essential to the advancement of a wide range of applications including tissue engineering, stem cell and cancer research. Precise cell placement, especially of multiple cell types in co- or multi-cultures and in three dimensions, can enable research possibilities otherwise impossible, such as the cell-by-cell assembly of complex cellular constructs. Laser-based direct writing, a printing technique first utilized in electronics applications, has been adapted to transfer living cells and other biological materials (e.g., enzymes, proteins and bioceramics). Many different cell types have been printed using laser-based direct writing, and this technique offers significant improvements when compared to conventional cell patterning techniques. The predominance of work to date has not been in application of the technique, but rather focused on demonstrating the ability of direct writing to pattern living cells, in a spatially precise manner, while maintaining cellular viability. This paper reviews laser-based additive direct-write techniques for cell printing, and the various cell types successfully laser direct-written that have applications in tissue engineering, stem cell and cancer research are highlighted. A particular focus is paid to process dynamics modeling and process-induced cell injury during laser-based cell direct writing. (topical review)

CT colonography: Techniques, indications, findings

International Nuclear Information System (INIS)

Mang, Thomas; Graser, Anno; Schima, Wolfgang; Maier, Andrea

2007-01-01

Computed tomographic colonography (CTC) is a minimally invasive technique for imaging the entire colon. Based on a helical thin-section CT of the cleansed and air-distended colon, two-dimensional and three-dimensional projections are used for image interpretation. Several clinical improvements in patient preparation, technical advances in CT, and new developments in evaluation software have allowed CTC to develop into a powerful diagnostic tool. It is already well established as a reliable diagnostic tool in symptomatic patients. Many experts currently consider CTC a comparable alternative to conventional colonoscopy, although there is still debate about its sensitivity for the detection of colonic polyps in a screening population. This article summarizes the main indications, the current techniques in patient preparation, data acquisition and data analysis as well as imaging features for common benign and malignant colorectal lesions

Making mock-FNA smears from fresh surgical pathology specimens to improve smear preparation technique and to create cytohistological correlation series.

Directory of Open Access Journals (Sweden)

Tibor Mezei

Full Text Available Fine needle aspiration (FNA cytology is a well-established diagnostic method based on the microscopic interpretation of often scant cytological material; therefore, experience, good technique and smear quality are equally important in obtaining satisfactory results.We studied the use of fresh surgical pathology specimens for making so-called mock-FNA smears with the potential of cytohistological correlation. Additionally, we studied how this process aids the improvement of preparation technique and smear quality.Cytological aspirates from 32 fresh biopsy specimens from various sites: lung (20, lymph nodes (6, and breast (6 were obtained, all with a clinical diagnosis of tumor. Aspiration was performed from grossly palpable tumors. 25 G needle and Cameco-type syringe holder was used with minimal or no suction.Unfixed surgical specimens provided sufficient cytological material that resulted in good quality smears. After standard processing of specimens into microscopic sections from paraffin embedded tissues, cytohistological case-series were created. No significant alteration was reported in tissue architecture on hematoxylin-eosin stained sections after the aspiration procedure. A gradual, but steady improvement was observed in smear quality just after a few preparations.Our study proved that surgical specimens may be used as a source of cytological material to create cytohistological correlation studies and also to improve FNA cytology skills. The use of very fine gauge needle (25 G, 0,6 mm diameter during the sampling process does not alter tissue architecture therefore the final histopathological diagnosis is not compromised. We conclude that by using fresh surgical specimens useful cytohistological collections can be created both as a teaching resource and as improving experience.

Hydrogel Based on Crosslinked Methylcellulose Prepared by Electron Beam Irradiation for Wound Dressing Application

Directory of Open Access Journals (Sweden)

Ambyah Suliwarno

2014-10-01

Full Text Available The aim of this research is to explore the possibility of methylcellulose polymer to be used as wound dressing material prepared using electron beam technique. The methylcellulose paste solution with various of molecular weight (SM-4, SM-100, SM-400, SM-4000 and SM-8000 at different concentration (15-30% w/v were irradiated by using electron beam on the dose range of 10 kGy up to 40 kGy. Gel fraction and swelling ratio of hydrogels were determined gravimetrically. Tensile strength and elasticity of hydrogels were measured using a universal testing machine. It was found that with the increasing of irradiation dose from 10 up to 40 kGy, gel fraction and tensile strength were increased for all of hydrogels with various of molecular weight. On contrary, the swelling ratio of hydrogels decreased with increasing of irradiation dose. The optimum hydrogels elasticity were obtained from methylcellulose solution with the concentration range of 15-20% with irradiation dose of 20 kGy and showed excellent performance. The hydrogels based on methylcellulose prepared by electron beam irradiation can be considered for wound dressing material.

Rapid analysis of steels using laser-based techniques

International Nuclear Information System (INIS)

Cremers, D.A.; Archuleta, F.L.; Dilworth, H.C.

1985-01-01

Based on the data obtained by this study, we conclude that laser-based techniques can be used to provide at least semi-quantitative information about the elemental composition of molten steel. Of the two techniques investigated here, the Sample-Only method appears preferable to the LIBS (laser-induced breakdown spectroscopy) method because of its superior analytical performance. In addition, the Sample-Only method would probably be easier to incorporate into a steel plant environment. However, before either technique can be applied to steel monitoring, additional research is needed

Preparing Methods and Its Influencing Factors about Nanoparticles Based on Dendritic Polymer

OpenAIRE

Zhang Jianwei; Li Jeff

2017-01-01

Based on the properties, structure and application of dendritic polymer, this paper analysed the methods of the preparation of nanoparticles using dendritic polymer, detailed preparation process, technical parameters and application effect about a single metal nanoparticles, bimetallic nanoparticles, sulfide and halide nanoparticles. The influencing factors of the preparation about nanoparticles were discussed, including the molecular algebra, the molar ratio of the metal ions to the dendriti...

Preparation and characterization of monodisperse microcapsules with alginate and bentonite via external gelation technique encapsulating Pseudomonas putida Rs-198.

Science.gov (United States)

Li, Xuan; Wu, Zhansheng; He, Yanhui; Ye, Bang-Ce; Wang, Jun

2017-10-01

This paper evaluated the external gelation technique for preparing microcapsules. The microcapsules were consisted of Pseudomonas putida Rs-198 (Rs-198) core and sodium alginate (NaAlg)-bentonite (Bent) shell. Different emulsification rotation speeds and core/shell ratios were used to prepare the microcapsules of each formulation. The near-spherical microcapsules were monodisperse with a mean diameter of 25-100 μm and wrinkled surfaces. Fourier transform infrared spectrophotometry (FTIR) and thermogravimetric analysis (TGA) revealed the physical mixture of the wall material and the superior thermal stability of the microcapsules. Percentage yield, water content, and encapsulation efficiency were evaluated and correlated with the changes in emulsification rotation speed and core/shell ratio. In vitro release experiments demonstrated that 60% of the bacteria were released from the NaAlg-Bent microcapsules within three days. Considerably better survival was observed for encapsulated cells compared to free cells, especially in pH 4.0 and 10.0. In summary, the desired properties of microcapsules can be obtained by external gelation technique and the microcapsules on the bacteria had a good protective effect.

ZnO and copper indium chalcogenide heterojunctions prepared by inexpensive methods

Energy Technology Data Exchange (ETDEWEB)

Berruet, M., E-mail: berruetm@gmail.com [División Electroquímica y Corrosión, Facultad de Ingeniería, INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Di Iorio, Y. [División Electroquímica y Corrosión, Facultad de Ingeniería, INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Troviano, M. [Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas (PROBIEN, CONICET-UNCo), Buenos Aires 1400, Q8300IBX Neuquén (Argentina); Vázquez, M. [División Electroquímica y Corrosión, Facultad de Ingeniería, INTEMA, CONICET, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, B7608FDQ Mar del Plata (Argentina)

2014-12-15

Solution-based techniques were used to prepare ZnO/CuIn(Se, S){sub 2} heterojunctions that serve as solar cell prototypes. A duplex layer of ZnO (compact + porous) was electrodeposited. Chalcogenide thin films were deposited using successive ionic layer adsorption and reaction method (SILAR). By subsequent thermal treatments in two different atmospheres, CuInSe{sub 2} (CISe) and CuInSe{sub 2−x}S{sub x} (CISeS) were obtained. The composition and morphology of the annealed films were characterized by GXRD, micro-Raman spectroscopy and SEM. Devices prepared with CISe and CISeS show a clear photo-response. The introduction of a buffer layer of TiO{sub 2} into the ZnO/chalcogenide interface was necessary to detect photocurrent. The presence of CISeS improves the response of the cell, with higher values of short circuit current density, open circuit potential and fill factor. These promising results show that it is possible to prepare photovoltaic heterojunctions by depositing chalcogenides onto porous ZnO substrates using low-cost solution-based techniques. - Highlights: • Heterojunctions that serve as solar cell prototypes were prepared using solution-based techniques. • The devices comprised a double layer of ZnO and CuInSe{sub 2} or CuInSe{sub 0.4}S{sub 1.6}. • A TiO{sub 2} buffer layer in the ZnO/chalcogenide interface is necessary to detect photocurrent. • The incorporation of S improved the response of the photovoltaic heterojunction.

Characterization of binary gold/platinum nanoparticles prepared by sonochemistry technique

International Nuclear Information System (INIS)

Nakanishi, M.; Takatani, H.; Kobayashi, Y.; Hori, F.; Taniguchi, R.; Iwase, A.; Oshima, R.

2005-01-01

Aqueous solutions with Au 3+ and Pt 4+ ions and additives of surfactants (SDS or PEG-MS) were irradiated with an ultrasound at 200 kHz with an input power of 4.2 W/cm 2 , and colloidal nanoparticles were prepared. The prepared nanoparticles were characterized by XRD, TEM, HRTEM, EDX and 197 Au Moessbauer spectroscopy. It was found that the structures of nanoparticles were changed with the surfactants; Au and Pt nanoparticles were prepared individually by using SDS, and bimetallic Au/Pt alloy nanoparticles with a core-shell structure were produced in the presence of PEG-MS

Preparation and characterization of perovskite structure lanthanum gallate and lanthanum aluminate based oxides

OpenAIRE

Li, Shuai

2009-01-01

The present work was initiated to study the synthesis and properties of lanthanum gallate based oxides as intermediate temperature electrolyte for solid oxide fuel cells. The wet chemical method, polymer complexing route, was used to prepare the precursor powders. To further investigate the polymer complexing method, it was also applied to the preparation of lanthanum aluminate based oxides.   Single perovskite phase La0.8Sr0.2Ga0.83Mg0.17O2.815 can be prepared by the polymer complexing meth...

Implementation of an office-based semen preparation method (SEP ...

African Journals Online (AJOL)

Implementation of an office-based semen preparation method (SEP-D Kit) for intra-uterine insemination (IUI): A controlled randomised study to compare the IUI pregnancy outcome between a routine (swim-up) and the SEP-D Kit method.

Developing a hybrid dictionary-based bio-entity recognition technique

Science.gov (United States)

2015-01-01

Background Bio-entity extraction is a pivotal component for information extraction from biomedical literature. The dictionary-based bio-entity extraction is the first generation of Named Entity Recognition (NER) techniques. Methods This paper presents a hybrid dictionary-based bio-entity extraction technique. The approach expands the bio-entity dictionary by combining different data sources and improves the recall rate through the shortest path edit distance algorithm. In addition, the proposed technique adopts text mining techniques in the merging stage of similar entities such as Part of Speech (POS) expansion, stemming, and the exploitation of the contextual cues to further improve the performance. Results The experimental results show that the proposed technique achieves the best or at least equivalent performance among compared techniques, GENIA, MESH, UMLS, and combinations of these three resources in F-measure. Conclusions The results imply that the performance of dictionary-based extraction techniques is largely influenced by information resources used to build the dictionary. In addition, the edit distance algorithm shows steady performance with three different dictionaries in precision whereas the context-only technique achieves a high-end performance with three difference dictionaries in recall. PMID:26043907

Developing a hybrid dictionary-based bio-entity recognition technique.

Science.gov (United States)

Song, Min; Yu, Hwanjo; Han, Wook-Shin

2015-01-01

Bio-entity extraction is a pivotal component for information extraction from biomedical literature. The dictionary-based bio-entity extraction is the first generation of Named Entity Recognition (NER) techniques. This paper presents a hybrid dictionary-based bio-entity extraction technique. The approach expands the bio-entity dictionary by combining different data sources and improves the recall rate through the shortest path edit distance algorithm. In addition, the proposed technique adopts text mining techniques in the merging stage of similar entities such as Part of Speech (POS) expansion, stemming, and the exploitation of the contextual cues to further improve the performance. The experimental results show that the proposed technique achieves the best or at least equivalent performance among compared techniques, GENIA, MESH, UMLS, and combinations of these three resources in F-measure. The results imply that the performance of dictionary-based extraction techniques is largely influenced by information resources used to build the dictionary. In addition, the edit distance algorithm shows steady performance with three different dictionaries in precision whereas the context-only technique achieves a high-end performance with three difference dictionaries in recall.

Synthesis, microstructure and mechanical properties of ceria stabilized tetragonal zirconia prepared by spray drying technique

International Nuclear Information System (INIS)

Sharma, S.C.; Gokhale, N.M.; Dayal, Rajiv; Lazl, Ramji

2002-01-01

Ceria stabilized zirconia powders with ceria concentration varying from 6 to 16 mol% were synthesized using spray drying technique. Powders were characterized for their particle size distribution and specific surface area. The dense sintered ceramics fabricated using these powders were characterized for their microstructure, crystallite size and phase composition. The flexural strength, fracture toughness and micro-hardness of sintered ceramics were measured. High fracture toughness and flexural strength were obtained for sintered bodies with 12 mol% of CeO 2 . Flexural strength and fracture toughness were dependent on CeO 2 concentration, crystallite size and phase composition of sintered bodies. Correlation of data has indicated that the transformable tetragonal phase is the key factor in controlling the fracture toughness and strength of ceramics. It has been demonstrated that the synthesis method is effective to prepare nanocrystalline tetragonal ceria stabilized zirconia powders with improved mechanical properties. Ce-ZrO 2 with 20 wt% alumina was also prepared with flexural strength, 1200 MPa and fracture toughness 9.2 MPa√m. (author)

Contribution of NAA and other techniques to the certification of two new Polish CRMs prepared by INCT

International Nuclear Information System (INIS)

Dybczynski, R.; Danko, B.; Kulisa, K.; Maleszewska, E.; Polkowska-Motrenko, H.; Samczynski, Z.; Szopa, Z.

2002-01-01

Two new reference materials of biological origin, namely Tea Leaves (INCTTL-1 ) and Mixed Polish Herbs (INCT-MPH-2), were prepared, and a worldwide interlaboratory comparison in which more than 100 laboratories participated was organized with the aim to certify these materials for the content of possibly a great number of trace elements. In this paper a preliminary analysis of the contribution of various analytical techniques to the certification of the new reference materials is presented and discussed with special emphasis on the role played by neutron activation analysis (NAA) and other radiometric techniques. The significance of 'very accurate methods' by radiochemical NAA in the certification process is pointed out. An attempt is made to compare the outcome of the present intercomparison with those formerly organized by INCT as well as with some earlier IAEA intercomparisons in order to demonstrate similarities, differences and trends in the use of the various analytical techniques in trace analysis as a function of time. (author)

Chemical preparation of graphene-based nanomaterials and their applications in chemical and biological sensors.

Science.gov (United States)

Jiang, Hongji

2011-09-05

Graphene is a flat monolayer of carbon atoms packed tightly into a 2D honeycomb lattice that shows many intriguing properties meeting the key requirements for the implementation of highly excellent sensors, and all kinds of proof-of-concept sensors have been devised. To realize the potential sensor applications, the key is to synthesize graphene in a controlled way to achieve enhanced solution-processing capabilities, and at the same time to maintain or even improve the intrinsic properties of graphene. Several production techniques for graphene-based nanomaterials have been developed, ranging from the mechanical cleavage and chemical exfoliation of high-quality graphene to direct growth onto different substrates and the chemical routes using graphite oxide as a precusor to the newly developed bottom-up approach at the molecular level. The current review critically explores the recent progress on the chemical preparation of graphene-based nanomaterials and their applications in sensors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Colloidal silver nanoparticles prepared by UV-light induced citrate reduction technique for the quantitative detection of uric acid

Science.gov (United States)

Maity, Anupam; Panda, Sovan Kumar

2018-04-01

Reddish-yellow color colloid consisting of silver nanoparticles (Ag NPs) has been synthesized by reducing aqueous AgNO3 solution by photo-induced citrate reduction technique under UV light. As prepared colloid exhibits single and intense plasmonic absorption peak in the violet region of the visible spectra with the peak centered at 405 nm. The NPs are fine and spherical with diameter ranging from 5 to 10 nm. These colloidal NPs have been used for the quantitative detection of uric acid by UV-VIS spectroscopy. A linear red shifting of the characteristics Plasmonic absorption peak of Ag NPs is observed with uric acid concentration. Uric acid can be detected by UV-VIS spectroscopy down to 5 nM limit using the prepared colloid.

Bowel preparation for CT colonography

International Nuclear Information System (INIS)

Neri, Emanuele; Lefere, Philippe; Gryspeerdt, Stefaan; Bemi, Pietro; Mantarro, Annalisa; Bartolozzi, Carlo

2013-01-01

Bowel preparation represents an essential part of CT colonography, as the accuracy of the exam is strongly related to the adequacy of colonic cleansing, and a poor bowel preparation may compromise the diagnostic quality even despite optimization of all other acquisition parameters. Residual stool and fluid in the large bowel may affect the interpretation of the exam and may increase the number of false positives and false negatives. In this regard, the majority of patients having undergone CT colonography state that bowel preparation is the most unpleasant part. Unfortunately, to date no definite consensus has been reached about the ideal bowel preparation technique, and there is great variability in preparation strategies across diagnostic centers. The purpose of this review article is to describe the development and evolution of bowel preparation techniques in order to choose the best approach for optimizing the diagnostic quality of CT colonography in each patient

Bowel preparation for CT colonography

Energy Technology Data Exchange (ETDEWEB)

Neri, Emanuele, E-mail: emanuele.neri@med.unipi.it [Diagnostic and Interventional Radiology, University of Pisa (Italy); Lefere, Philippe; Gryspeerdt, Stefaan [Department of Radiology, Stedelijk Ziekenhuis, Roeselare (Belgium); Bemi, Pietro; Mantarro, Annalisa; Bartolozzi, Carlo [Diagnostic and Interventional Radiology, University of Pisa (Italy)

2013-08-15

Bowel preparation represents an essential part of CT colonography, as the accuracy of the exam is strongly related to the adequacy of colonic cleansing, and a poor bowel preparation may compromise the diagnostic quality even despite optimization of all other acquisition parameters. Residual stool and fluid in the large bowel may affect the interpretation of the exam and may increase the number of false positives and false negatives. In this regard, the majority of patients having undergone CT colonography state that bowel preparation is the most unpleasant part. Unfortunately, to date no definite consensus has been reached about the ideal bowel preparation technique, and there is great variability in preparation strategies across diagnostic centers. The purpose of this review article is to describe the development and evolution of bowel preparation techniques in order to choose the best approach for optimizing the diagnostic quality of CT colonography in each patient.

Guide to nondestructive assay standards: Preparation criteria, availability, and practical considerations

International Nuclear Information System (INIS)

Stewart, J.E.; Hsue, S.T.; Sampson, T.E.

1997-01-01

For certification and measurement control, nondestructive assay (NDA) instruments and methods used for verification measurement of special nuclear materials (SNMs) require calibrations based on certified reference materials (CRMs), or working reference materials (WRMs), traceable to the national system of measurements, and adequately characteristic of the unknowns. The Department of Energy Office of Safeguards and Security is sponsoring production of a comprehensive guide to preparation of NDA standards. The scope of the report includes preparation criteria, current availability of CRMs and WRMs, practical considerations for preparation and characterization, and an extensive bibliography. In preparing the report, based primarily on experience at Los Alamos, we have found that standards preparation is highly dependent on the particular NDA method being applied. We therefore include sections that contain information specific to commonly used neutron and gamma-ray NDA techniques. 16 refs., 4 figs., 2 tabs

Preparation of thin nuclear targets

International Nuclear Information System (INIS)

Muggleton, A.H.F.

1979-03-01

Thin film backings, sources and targets are needed for many applications in low energy nuclear physics and nuclear chemistry experiments. A survey of techniques used in the preparation of nuclear targets is first briefly discussed. These are classified as chemical, mechanical and physical preparations. Vacuum evaporation, being the most generally used technique, is discussed in detail. It is highly desirable to monitor the film thickness and control the deposition rate during evaporation and to measure the final target thickness after deposition has concluded. The relative merits of various thickness measuring techniques are described. Stages in the fabrication and mounting of self-supporting foils are described in detail, with emphasis given to the preparation of thin self-supporting carbon foils used as target backings and stripper foils. Various target backings, and the merits of the more generally used release agents are described in detail. The preparations of more difficult elemental targets are discussed, and a comprehensive list of the common targets is presented

Huffman-based code compression techniques for embedded processors

KAUST Repository

Bonny, Mohamed Talal

2010-09-01

The size of embedded software is increasing at a rapid pace. It is often challenging and time consuming to fit an amount of required software functionality within a given hardware resource budget. Code compression is a means to alleviate the problem by providing substantial savings in terms of code size. In this article we introduce a novel and efficient hardware-supported compression technique that is based on Huffman Coding. Our technique reduces the size of the generated decoding table, which takes a large portion of the memory. It combines our previous techniques, Instruction Splitting Technique and Instruction Re-encoding Technique into new one called Combined Compression Technique to improve the final compression ratio by taking advantage of both previous techniques. The instruction Splitting Technique is instruction set architecture (ISA)-independent. It splits the instructions into portions of varying size (called patterns) before Huffman coding is applied. This technique improves the final compression ratio by more than 20% compared to other known schemes based on Huffman Coding. The average compression ratios achieved using this technique are 48% and 50% for ARM and MIPS, respectively. The Instruction Re-encoding Technique is ISA-dependent. It investigates the benefits of reencoding unused bits (we call them reencodable bits) in the instruction format for a specific application to improve the compression ratio. Reencoding those bits can reduce the size of decoding tables by up to 40%. Using this technique, we improve the final compression ratios in comparison to the first technique to 46% and 45% for ARM and MIPS, respectively (including all overhead that incurs). The Combined Compression Technique improves the compression ratio to 45% and 42% for ARM and MIPS, respectively. In our compression technique, we have conducted evaluations using a representative set of applications and we have applied each technique to two major embedded processor architectures

The influence of polishing techniques on pre-polymerized CAD\\CAM acrylic resin denture bases.

Science.gov (United States)

Alammari, Manal Rahma

2017-10-01

Lately, computer-aided design and computer-aided manufacturing (CAD/CAM) has broadly been successfully employed in dentistry. The CAD/CAM systems have recently become commercially available for fabrication of complete dentures, and are considered as an alternative technique to conventionally processed acrylic resin bases. However, they have not yet been fully investigated. The purpose of this study was to inspect the effects of mechanical polishing and chemical polishing on the surface roughness (Ra) and contact angle (wettability) of heat-cured, auto-cured and CAD/CAM denture base acrylic resins. This study was conducted at the Advanced Dental Research Laboratory Center of King Abdulaziz University from March to June 2017. Three denture base materials were selected: heat cure poly-methylmethacrylate resin, thermoplastic (polyamide resin) and (CAD\\CAM) denture base resin. Sixty specimens were prepared and divided into three groups, twenty in each. Each group was divided according to the polishing techniques into (Mech P) and (Chem P), ten specimens in each; surface roughness and wettability were investigated. Data were analyzed by SPSS version 22, using one-way ANOVA and Pearson coefficient. One-way analysis of variance (ANOVA) and post hoc tests were used for comparing the surface roughness values between three groups which revealed a statistical significant difference between them (p 1 CAD\\CAM denture base material (group III) showed the least mean values (1.08±0.23, 1.39±0.31, Mech P and Chem P respectively). CAD/CAM showed the least contact angle in both polishing methods, which were statistically significant at 5% level (p=0.034 and pCAD\\CAM denture base resin with superior smooth surface compared to chemical polishing. Mechanical polishing is considered the best effective polishing technique. CAD/CAM denture base material should be considered as the material of choice for complete denture construction in the near future, especially for older dental

Preparation of high-purity cerium nitrate

International Nuclear Information System (INIS)

Avila, Daniela Moraes; Silva Queiroz, Carlos Alberto da; Santos Mucillo, Eliana Navarro dos

1995-01-01

The preparation of high-purity cerium nitrate has been carried out Cerium oxide has been prepared by fractioned precipitation and ionic exchange techniques, using a concentrate with approximately 85% of cerium oxide from NUCLEMON as raw material. Five sequential ion-exchange columns with a retention capacity of 170 g each have been used. The ethylenediamine-tetraacetic acid (EDTA) was used as eluent. The cerium content has been determined by gravimetry and iodometry techniques. The resulting cerium oxide has a purity > 99%. This material was transformed in cerium nitrate to be used as precursor for the preparation of Zirconia-ceria ceramics by the coprecipitation technique. (author)

Sample preparation guidelines for two-dimensional electrophoresis.

Science.gov (United States)

Posch, Anton

2014-12-01

Sample preparation is one of the key technologies for successful two-dimensional electrophoresis (2DE). Due to the great diversity of protein sample types and sources, no single sample preparation method works with all proteins; for any sample the optimum procedure must be determined empirically. This review is meant to provide a broad overview of the most important principles in sample preparation in order to avoid a multitude of possible pitfalls. Sample preparation protocols from the expert in the field were screened and evaluated. On the basis of these protocols and my own comprehensive practical experience important guidelines are given in this review. The presented guidelines will facilitate straightforward protocol development for researchers new to gel-based proteomics. In addition the available choices are rationalized in order to successfully prepare a protein sample for 2DE separations. The strategies described here are not limited to 2DE and can also be applied to other protein separation techniques.

Preparation of eugenol-based polyurethane

Science.gov (United States)

Li, Yupeng; Luo, Fang; Cheng, Chuanjie

2018-03-01

The regenerative eugenol was used as the starting material to prepare diol species by two steps, with a total yield of 28%. Furthermore, the prepared diol reacts with 1,6-hexadiisocyanate(HDI) to afford the corresponding polyurethane (PU). The structure of intermediates and PU are characterized by 1H-NMR or IR.

Preparation and Optimization OF Palm-Based Lipid Nanoparticles Loaded with Griseofulvin.

Science.gov (United States)

Huei Lim, Wen; Jean Tan, Yann; Sin Lee, Choy; Meng Er, Hui; Fung Wong, Shew

2017-01-01

Palm-based lipid nanoparticle formulation loaded with griseofulvin was prepared by solvent-free hot homogenization method. The griseofulvin loaded lipid nanoparticles were prepared via stages of optimisation, by altering the high pressure homogenisation (HPH) parameters, screening on palm-based lipids and Tween series surfactants and selection of lipid to surfactant ratios. A HPLC method has been validated for the drug loading capacity study. The optimum HPH parameter was determined to be 1500 bar with 5 cycles and among the palm-based lipid materials; Lipid C (triglycerides) was selected for the preparation of lipid nanoparticles. Tween 80 was chosen from the Tween series surfactants for its highest saturated solubility of griseofulvin at 53.1 ± 2.16 µg/mL. The optimum formulation of the griseofulvin loaded lipid nanoparticles demonstrated nano-range of particle size (179.8 nm) with intermediate distribution index (PDI) of 0.306, zeta potential of -27.9 mV and drug loading of 0.77%. The formulation was stable upon storage for 1 month at room temperature (25 ° C) and 45 ° C with consistent drug loading capacity.

Psychological Preparation for Peak Performance in Sports Competition

Science.gov (United States)

Ohuruogu, Ben; Jonathan, Ugwuanyi I.; Ikechukwu, Ugwu Jude

2016-01-01

This paper attempts to make an overview of various techniques, sport psychologist adopt in psychological preparation of athletes for peak performance. To attain peak performance in sports competitions, coaches and athletes should not base their prospect on physical training on sport skills alone rather should integrate both the mental and physical…

Hard dental tissue minimal-invasive preparation using contemporary polymer rotating instruments and laser

Directory of Open Access Journals (Sweden)

Beloica Miloš

2014-01-01

Full Text Available Goal of contemporary dentistry is to decrease the patient’s discomfort during treatment. Dentists aim to achieve maximum with the newly developed dental materials as well as with new cavity preparation techniques in the shortest time span. Since the development of the first constructed borer (drilling machine for caries removal, the preparation techniques have considerably changed. The progress of dental materials as well as the cavity preparation techniques has led us to contemporary carbide tungsten and diamond borers that are used with obligatory water cooling. The innovation within this field represents newly developed polymer borers that can detect the difference between carious lesions and healthy tooth structure. In this way the cavity preparation may be performed without damaging dental healthy tissue. This is possible owing to their hardness which is lower than the hardness of intact dentin. Polymer borer preparation is painless with less vibration, while the increase in temperature is negligible. Lasers have been used in clinical dentistry since 1980s so it can be said that they represent a new technology. The function of lasers is based on ablation which requires water. Erbium lasers have shown the highest potential with their ability to produce effective ablation of hard dental tissues. Laser application in dentistry requires special training as well as some protective measures. Laser advantages, compared to traditional preparation techniques, involve the absence of vibration, painless preparation, possibility of preparation without anesthetic and easier patient’s adjustment to dental intervention which is of importance, especially in pediatric dentistry. [Projekat Ministarstva nauke Republike Srbije, br. 46009

Synthesis, structural investigation and magnetic properties of Zn{sup 2+} substituted cobalt ferrite nanoparticles prepared by the sol–gel auto-combustion technique

Energy Technology Data Exchange (ETDEWEB)

Raut, A.V., E-mail: nano9993@gmail.com [Vivekanand Arts and Sardar Dalipsingh Commerce and Science College, Aurangabad, 431004 Maharastra (India); Barkule, R.S.; Shengule, D.R. [Vivekanand Arts and Sardar Dalipsingh Commerce and Science College, Aurangabad, 431004 Maharastra (India); Jadhav, K.M., E-mail: drjadhavkm@gmail.com [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, 431004 Maharastra (India)

2014-05-01

Structural morphology and magnetic properties of the Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (0.0≤x≥1.0) spinel ferrite system synthesized by the sol–gel auto-combustion technique using nitrates of respective metal ions have been studied. The ratio of metal nitrates to citric acid was taken at 1:3. The as prepared powder of cobalt zinc ferrite was sintered at 600 °C for 12 h after TG/DTA thermal studies. Compositional stoichiometry was confirmed by energy dispersive analysis of the X-ray (EDAX) technique. Single phase cubic spinel structure of Co–Zn nanoparticles was confirmed by XRD data. The average crystallite size (t), lattice constant (a) and other structural parameters of zinc substituted cobalt ferrite nanoparticles were calculated from XRD followed by SEM and FTIR. It is observed that the sol–gel auto-combustion technique has many advantages for the synthesis of technologically applicable Co–Zn ferrite nanoparticles. The present investigation clearly shows the effect of the synthesis method and possible relation between magnetic properties and microstructure of the prepared samples. Increase in nonmagnetic Zn{sup 2+} content in cobalt ferrite nanoparticles is followed by decrease in n{sub B}, M{sub s} and other magnetic parameters. Squareness ratio for the Co-ferrite was 1.096 at room temperature. - Highlights: • Co–Zn nanoparticles are prepared by sol–gel auto-combustion method. • Structural properties were characterized by XRD, SEM, and FTIR. • Compositional stoichiometry was confirmed by EDAX analysis. • Magnetic parameters were measured by the pulse field hysteresis loop technique.

Synchrotron radiation based analytical techniques (XAS and XRF)

International Nuclear Information System (INIS)

Jha, Shambhu Nath

2014-01-01

A brief description of the principles of X-ray absorption spectroscopy (XAS) and X-ray fluorescence (XRF) techniques is given in this article with emphasis on the advantages of using synchrotron radiation-based instrumentation/beamline. XAS technique is described in more detail to emphasize the strength of the technique as a local structural probe. (author)

Comparing Four Touch-Based Interaction Techniques for an Image-Based Audience Response System

NARCIS (Netherlands)

Jorritsma, Wiard; Prins, Jonatan T.; van Ooijen, Peter M. A.

2015-01-01

This study aimed to determine the most appropriate touch-based interaction technique for I2Vote, an image-based audience response system for radiology education in which users need to accurately mark a target on a medical image. Four plausible techniques were identified: land-on, take-off,

Impact of ignition temperature on particle size and magnetic properties of CoFe{sub 2}O{sub 4} nanoparticles prepared by self-propagated MILD combustion technique

Energy Technology Data Exchange (ETDEWEB)

Kaliyamoorthy, Venkatesan; Rajan Babu, D., E-mail: drajanbabu@vit.ac.in; Saminathan, Madeswaran

2016-11-15

We prepared nanocrystalline CoFe{sub 2}O{sub 4} by changing its ignition temperatures, using moderate and intense low-oxygen dilution (MILD) combustion technique. The effect of ignition temperature on the particle size and its magnetic behavior was investigated by HR-TEM and VSM respectively. We observed a vast change in the structural behavior and the magnetic properties of the prepared samples. X-ray diffraction studies revealed that the resultant samples had single phase with different grain sizes from 23±5 nm to 16±5 nm, which was understood by observing the growth of the grains through heat released from the combustion reaction. FE-SEM analysis showed high porosity with heterogeneous distribution of the pore size based on the adiabatic temperature and EPMA analysis, which confirmed the elemental compositions of the prepared samples. The saturation magnetization values measured at room temperature, employing vibrating sample magnetometer (VSM) decreased gradually from 50 to 34 emu/g when the ignition temperature was increased from 243 °C to 400 °C. Some of Fe ions on the B sites moved periodically to the A sites because of quenching treatment. The presence of Fe{sup 2+} ions in the existing ferrite structure ruled the magnetic behavior of the sample, as confirmed by the Mössbauer analysis. - Highlights: • CoFe{sub 2}O{sub 4} magnetic nanoparticles were prepared by MILD combustion technique. • Structural behavior and magnetic properties were changed by ignition temperature. • Formation of ferrite complex was confirmed by using FT-IR spectroscopy. • FE-SEM image confirmed the combustion nature by exhibiting the pores and voids. • The cationic distributions were investigated by the Mössbauer analysis.

Parametric Grid Information in the DOE Knowledge Base: Data Preparation, Storage, and Access

International Nuclear Information System (INIS)

Hipp, James R.; Moore, Susan G.; Myers, Stephen C.; Schultz, Craig A.; Shepherd, Ellen; Young, Christopher J.

1999-01-01

The parametric grid capability of the Knowledge Base provides an efficient, robust way to store and access interpolatable information which is needed to monitor the Comprehensive Nuclear Test Ban Treaty. To meet both the accuracy and performance requirements of operational monitoring systems, we use a new approach which combines the error estimation of kriging with the speed and robustness of Natural Neighbor Interpolation (NNI). The method involves three basic steps: data preparation (DP), data storage (DS), and data access (DA). The goal of data preparation is to process a set of raw data points to produce a sufficient basis for accurate NNI of value and error estimates in the Data Access step. This basis includes a set of nodes and their connectedness, collectively known as a tessellation, and the corresponding values and errors that map to each node, which we call surfaces. In many cases, the raw data point distribution is not sufficiently dense to guarantee accurate error estimates from the NNI, so the original data set must be densified using a newly developed interpolation technique known as Modified Bayesian Kriging. Once appropriate kriging parameters have been determined by variogram analysis, the optimum basis for NNI is determined in a process they call mesh refinement, which involves iterative kriging, new node insertion, and Delauny triangle smoothing. The process terminates when an NNI basis has been calculated which will fir the kriged values within a specified tolerance. In the data storage step, the tessellations and surfaces are stored in the Knowledge Base, currently in a binary flatfile format but perhaps in the future in a spatially-indexed database. Finally, in the data access step, a client application makes a request for an interpolated value, which triggers a data fetch from the Knowledge Base through the libKBI interface, a walking triangle search for the containing triangle, and finally the NNI interpolation

The socio-economic base line survey; first chapter of the handbook under preparation: "Managing farmers: a handbook for working with farmers in irrigation and drainage projects"

NARCIS (Netherlands)

Schrevel, A.

2002-01-01

The text The socio-economic base line survey is the first chapter of a book under preparation meant to instruct senior staff of irrigation and drainage projects on techniques to work with farmers. It informs the reader of best practices to set up and execute a socio-economic baseline survey. The

Efficient techniques for wave-based sound propagation in interactive applications

Science.gov (United States)

Mehra, Ravish

Sound propagation techniques model the effect of the environment on sound waves and predict their behavior from point of emission at the source to the final point of arrival at the listener. Sound is a pressure wave produced by mechanical vibration of a surface that propagates through a medium such as air or water, and the problem of sound propagation can be formulated mathematically as a second-order partial differential equation called the wave equation. Accurate techniques based on solving the wave equation, also called the wave-based techniques, are too expensive computationally and memory-wise. Therefore, these techniques face many challenges in terms of their applicability in interactive applications including sound propagation in large environments, time-varying source and listener directivity, and high simulation cost for mid-frequencies. In this dissertation, we propose a set of efficient wave-based sound propagation techniques that solve these three challenges and enable the use of wave-based sound propagation in interactive applications. Firstly, we propose a novel equivalent source technique for interactive wave-based sound propagation in large scenes spanning hundreds of meters. It is based on the equivalent source theory used for solving radiation and scattering problems in acoustics and electromagnetics. Instead of using a volumetric or surface-based approach, this technique takes an object-centric approach to sound propagation. The proposed equivalent source technique generates realistic acoustic effects and takes orders of magnitude less runtime memory compared to prior wave-based techniques. Secondly, we present an efficient framework for handling time-varying source and listener directivity for interactive wave-based sound propagation. The source directivity is represented as a linear combination of elementary spherical harmonic sources. This spherical harmonic-based representation of source directivity can support analytical, data

Preparation of Candesartan and Atorvastatin Nanoparticles by Solvent Evaporation

Directory of Open Access Journals (Sweden)

Josef Jampilek

2012-11-01

Full Text Available The solubility, absorption and distribution of a drug are involved in the basic aspects of oral bioavailability Solubility is an essential characteristic and influences the efficiency of the drug. Over the last ten years, the number of poorly soluble drugs has steadily increased. One of the progressive ways for increasing oral bioavaibility is the technique of nanoparticle preparation, which allows many drugs to thus reach the intended site of action. Candesartan cilexetil and atorvastatin, belonging to class II of the biopharmaceutical classification system, were chosen as model active pharmaceutical ingredients in this study. Forty samples were prepared either by antisolvent precipitation/solvent evaporation method or by the emulsion/solvent evaporation technique with various commonly used surface-active excipients as nanoparticle stabilizers. All samples were analyzed by means of dynamic light scattering. The particle size of the determined 36 nanoparticle samples was to 574 nm, whereas 32 samples contained nanoparticles of less than 200 nm. Relationships between solvents and excipients used and their amount are discussed. Based on the results the investigated solvent evaporation methods can be used as an effective and an affordable technique for the preparation of nanoparticles.

A parylene-filled-trench technique for thermal isolation in silicon-based microdevices

International Nuclear Information System (INIS)

Lei Yinhua; Wang Wei; Li Ting; Jin Yufeng; Zhang Haixia; Li Zhihong; Yu Huaiqiang; Luo Yingcun

2009-01-01

Microdevices prepared in a silicon substrate have been widely used in versatile fields due to the matured silicon-based microfabrication technique and the excellent physical properties of silicon material. However, the high thermal conductivity of silicon restricts its application in most thermal microdevices, especially devices comprising different temperature zones. In this work, a parylene-filled-trench technique was optimized to realize high-quality thermal isolation in silicon-based microdevices. Parylene C, a heat transfer barricading material, was deposited on parallel high-aspect-ratio trenches, which surrounded the isolated target zones. After removing the remnant silicon beneath the trenches by deep reactive ion etching from the back side, a high-quality heat transfer barrier was obtained. By using narrow trenches, only 5 µm thick parylene was required for a complete filling, which facilitated multi-layer interconnection thereafter. The parylene filling performance inside the high-aspect-ratio trench was optimized by two approaches: multiple etch–deposition cycling and trench profile controlling. A 4 × 6 array, in which each unit was kept at a constant temperature and was well thermally isolated individually, was achieved on a silicon substrate by using the present parylene-filled-trench technique. The preliminary experimental results indicated that the present parylene-filled-trench structure exhibited excellent thermal isolation performance, with a very low power requirement of 0.134 mW (K mm 2 ) −1 for heating the isolated silicon unit and a high thermal isolation efficiency of 72.5% between two adjacent units. Accompanied with high-quality isolation performance, the microdevices embedded the present parylene-filled-trench structure to retain a strong mechanical connection larger than 400 kPa between two isolated zones, which is very important for a high-reliability-required micro-electro-mechanical-system (MEMS) device. Considering its room

Guide to nondestructive assay standards: Preparation criteria, availability, and practical considerations

International Nuclear Information System (INIS)

Hsue, S.T.; Stewart, J.E.; Sampson, T.E.; Butler, G.W.; Rudy, C.R.; Rinard, P.M.

1997-10-01

For certification and measurement control, nondestructive assay (NDA) instruments and methods used for verification measurements of special nuclear materials (SNMs) require calibrations based on certified reference materials (CRMs), or working reference materials (WRMs), traceable to the national system of measurements, and adequately characteristic of the unknowns. The Department of Energy Office of Safeguards and Security is sponsoring production of a comprehensive guide to preparation of NDA standards. The scope of the report includes preparation criteria, current availability of CRMs and WRMs, practical considerations for preparation and characterization, and an extensive bibliography. In preparing the report, based primarily on experience at Los Alamos, they have found that standards preparation is highly dependent on the particular NDA method being applied. They therefore include sections that contain information specific to commonly used neutron and gamma-ray NDA techniques. They also present approaches that are alternatives to, or minimize requirements for physical standards

Preparation and nucleation of spherical metallic droplet

Directory of Open Access Journals (Sweden)

Bing-ge Zhao

2015-03-01

Full Text Available The preparation and solidification of metallic droplets attract more and more attention for their significance in both engineering and scientific fields. In this paper, the preparation and characterization of Sn-based alloy droplets using different methods such as atomization and consumable electrode direct current arc (CDCA technique are reviewed. The morphology and structure of these droplets were determined by optical microscopy, X-ray diffraction (XRD and scanning electron microscopy (SEM. The solidification behavior of single droplet was systematically studied by means of scanning calorimetry (DSC, and the nucleation kinetics was also calculated. In particular, the development of fast scanning calorimetry (FSC made it possible to investigate the evolution of undercooling under ultrafast but controllable heating and cooling conditions. The combination of CDCA technique and FSC measurements opens up a new door for quantitative studies on droplet solidification, which is accessible to demonstrate some theories by experiments.

Preparation and temperature dependence of electrostriction properties for PMN-based composite ceramics

International Nuclear Information System (INIS)

Zhao Jingbo; Qu Shaobo; Du Hongliang; Zheng Yanju; Xu Zhuo

2009-01-01

Both low- and high-temperature units were prepared by columbite precursor method, and Pb(Mg 1/3 Nb 2/3 )O 3 (PMN)-based ferroelectric composite ceramics were prepared by conventional method, baking-block method and coating method, respectively. The effects of preparation methods on dielectric and electrostriction properties as well as the temperature-dependence property of the obtained composite ceramics were studied. The results show that compared with the samples prepared by traditional blend sintering method, of the samples prepared by baking-block and coating methods have much better dielectric and electrostriction properties. For those prepared by baking-block method, the electrostriction temperature-dependence properties are good in the range of 20-60 deg. C. For those prepared by coating method, the dielectric temperature-dependence properties are also good in the broad range of -30 to 70 deg. C, and the electrostriction temperature properties are better than those prepared by blending-block. Compared with the traditional blending sintering method, the dielectric and electrostriction temperature-dependence properties are much better, which effectively solves the problem of temperature properties existing in present engineering applications.

Uses of γ-radiation for preparing culture media

International Nuclear Information System (INIS)

Speranskaya, I.D.; Tumanyan, M.A.; Mironova, L.L.

1977-01-01

A technique has been developed for sterilizing the culture media by γ-radiation. For this purpose, dry preparations were exposed to doses of 3 to 6 Mrad and then dissolved in sterile distilled water. The quality of the preparations prepared in such a way is not inferior to that of the preparations sterilized by filtering. The advantage of the proposed technique is that it is possible to prepare liquid media quickly and to store dry sterile media for a long time at room temperature

Posterior indirect adhesive 
restorations: updated indications 
and the Morphology Driven 
Preparation Technique.

Science.gov (United States)

Veneziani, Marco

The aim of this article is to identify the indications for adhesively cemented restorations and to provide a correct step-by-step protocol for clinicians. New cavity preparation principles are based on morphological considerations in terms of geometry (maximum profile line and inclination of cusp lines), and structure (dentin concavity and enamel convexity). In this article, we discuss previous preparation concepts that were not designed purely for adhesive restorations and were therefore not conservative enough or suitable for adhesive procedures. The novel cavity shape consists of continuous inclined plane cavity margins (hollow chamfer or concave bevel) on axial walls, whenever they are coronal to the equatorial tooth line. A 1.2 mm-thick butt-joint preparation is performed in the interproximal box and on the axial walls when the margins are apical to the equatorial line. The occlusal surface is anatomically prepared, free of slots and angles. The author's suggestion is to avoid shoulder finish line preparation around cusps, occlusal slots, and pins, as they are less conservative, incompatible with adhesive procedures, and involve unnecessary dentin exposure. The clinical advantages of this new "anatomic" preparation design are 1) improving adhesion quality (optimizing the cutting of enamel prisms, and increasing the available enamel surface); 2) minimizing dentin exposure; 3) maximizing hard tissue preservation (the cavity being designed for cementation with reinforced composite resins, improvement of flow, and removal of excess material); 4) optimization of esthetic integration due to the inclined plane design, which permits a better blending at the transition area between tooth and restoration. These preparation principles may be effectively used for all adhesively cemented restorations, both according to traditional concepts (inlay, onlay, overlay) and new ones (additional overlay, occlusal-veneer, overlay-veneer, long-wrap overlay, adhesive crown). Thus, a

A comparison of two common sample preparation techniques for lipid and fatty acid analysis in three different coral morphotypes reveals quantitative and qualitative differences.

Science.gov (United States)

Conlan, Jessica A; Rocker, Melissa M; Francis, David S

2017-01-01

Lipids are involved in a host of biochemical and physiological processes in corals. Therefore, changes in lipid composition reflect changes in the ecology, nutrition, and health of corals. As such, accurate lipid extraction, quantification, and identification is critical to obtain comprehensive insight into a coral's condition. However, discrepancies exist in sample preparation methodology globally, and it is currently unknown whether these techniques generate analogous results. This study compared the two most common sample preparation techniques for lipid analysis in corals: (1) tissue isolation by air-spraying and (2) crushing the coral in toto . Samples derived from each preparation technique were subsequently analysed to quantify lipids and their constituent classes and fatty acids in four common, scleractinian coral species representing three distinct morphotypes ( Acropora millepora , Montipora crassotuberculata , Porites cylindrica , and Pocillopora damicornis ). Results revealed substantial amounts of organic material, including lipids, retained in the skeletons of all species following air-spraying, causing a marked underestimation of total lipid concentration using this method. Moreover, lipid class and fatty acid compositions between the denuded skeleton and sprayed tissue were substantially different. In particular, the majority of the total triacylglycerol and total fatty acid concentrations were retained in the skeleton (55-69% and 56-64%, respectively). As such, the isolated, sprayed tissue cannot serve as a reliable proxy for lipid quantification or identification in the coral holobiont. The in toto crushing method is therefore recommended for coral sample preparation prior to lipid analysis to capture the lipid profile of the entire holobiont, permitting accurate diagnoses of coral condition.

A comparison of two common sample preparation techniques for lipid and fatty acid analysis in three different coral morphotypes reveals quantitative and qualitative differences

Directory of Open Access Journals (Sweden)

Jessica A. Conlan

2017-08-01

Full Text Available Lipids are involved in a host of biochemical and physiological processes in corals. Therefore, changes in lipid composition reflect changes in the ecology, nutrition, and health of corals. As such, accurate lipid extraction, quantification, and identification is critical to obtain comprehensive insight into a coral’s condition. However, discrepancies exist in sample preparation methodology globally, and it is currently unknown whether these techniques generate analogous results. This study compared the two most common sample preparation techniques for lipid analysis in corals: (1 tissue isolation by air-spraying and (2 crushing the coral in toto. Samples derived from each preparation technique were subsequently analysed to quantify lipids and their constituent classes and fatty acids in four common, scleractinian coral species representing three distinct morphotypes (Acropora millepora, Montipora crassotuberculata, Porites cylindrica, and Pocillopora damicornis. Results revealed substantial amounts of organic material, including lipids, retained in the skeletons of all species following air-spraying, causing a marked underestimation of total lipid concentration using this method. Moreover, lipid class and fatty acid compositions between the denuded skeleton and sprayed tissue were substantially different. In particular, the majority of the total triacylglycerol and total fatty acid concentrations were retained in the skeleton (55–69% and 56–64%, respectively. As such, the isolated, sprayed tissue cannot serve as a reliable proxy for lipid quantification or identification in the coral holobiont. The in toto crushing method is therefore recommended for coral sample preparation prior to lipid analysis to capture the lipid profile of the entire holobiont, permitting accurate diagnoses of coral condition.

Characterization of dicalcium phosphate dihydrate cements prepared using a novel hydroxyapatite-based formulation

International Nuclear Information System (INIS)

Alge, Daniel L; Cruz, Grace Santa; Chu, Tien-Min Gabriel; Goebel, W Scott

2009-01-01

Dicalcium phosphate dihydrate (DCPD) cements are typically prepared using β-tricalcium phosphate (β-TCP) as the base component. However, hydroxyapatite (HA) is an interesting alternative because of its potential for reducing cement acidity, as well as modulating cement properties via ionic substitutions. In the present study, we have characterized DCPD cements prepared with a novel formulation based on monocalcium phosphate monohydrate (MCPM) and HA. Cements were prepared using a 4:1 MCPM:HA molar ratio. The reactivity of HA in this system was verified by showing DCPD formation using poorly crystalline HA, as well as highly crystalline HA. Evaluation of cements prepared with poorly crystalline HA revealed that setting occurs rapidly in the MCPM/HA system, and that the use of a setting regulator is necessary to maintain workability of the cement paste. Compressive testing showed that MCPM/HA cements have strengths comparable to what has previously been published for DCPD cements. However, preliminary in vitro analysis of cement degradation revealed that conversion of DCPD to HA may occur much more rapidly in the MCPM/HA system compared to cements prepared with β-TCP. Future studies should investigate this property further, as it could have important implications for the use of HA-based DCPD cement formulations.

Waste minimization in analytical chemistry through innovative sample preparation techniques

International Nuclear Information System (INIS)

Smith, L. L.

1998-01-01

Because toxic solvents and other hazardous materials are commonly used in analytical methods, characterization procedures result in significant and costly amount of waste. We are developing alternative analytical methods in the radiological and organic areas to reduce the volume or form of the hazardous waste produced during sample analysis. For the radiological area, we have examined high-pressure, closed-vessel microwave digestion as a way to minimize waste from sample preparation operations. Heated solutions of strong mineral acids can be avoided for sample digestion by using the microwave approach. Because reactivity increases with pressure, we examined the use of less hazardous solvents to leach selected contaminants from soil for subsequent analysis. We demonstrated the feasibility of this approach by extracting plutonium from a NET reference material using citric and tartaric acids with microwave digestion. Analytical results were comparable to traditional digestion methods, while hazardous waste was reduced by a factor often. We also evaluated the suitability of other natural acids, determined the extraction performance on a wider variety of soil types, and examined the extraction efficiency of other contaminants. For the organic area, we examined ways to minimize the wastes associated with the determination of polychlorinated biphenyls (PCBs) in environmental samples. Conventional methods for analyzing semivolatile organic compounds are labor intensive and require copious amounts of hazardous solvents. For soil and sediment samples, we have a method to analyze PCBs that is based on microscale extraction using benign solvents (e.g., water or hexane). The extraction is performed at elevated temperatures in stainless steel cells containing the sample and solvent. Gas chromatography-mass spectrometry (GC/MS) was used to quantitate the analytes in the isolated extract. More recently, we developed a method utilizing solid-phase microextraction (SPME) for natural

Tracer techniques in food industry

International Nuclear Information System (INIS)

Pertsovskij, E.S.; Sakharov, Eh.V.; Dolinin, V.A.

1980-01-01

The appicability of radioactive tracer techniques to process control in food industry are considered. Investigations in the field of food industry carried out using the above method are classified. The 1 class included investigations with preliminary preparation of a radioactive indicator and its following introduction in the system studied. The 2 class includes investigations based on the introduction in the system studied of a non-active indicator which is activated in a neutron flux being in samples selected in or after the process investigated. The 3 class includes studies based on investigations of natural radioactivity of certain nuclides in food stuff. The application of tracer techniques to the above classes of investigations in various fields of food industry and the equipment applied are considered in detail [ru

Power system stabilizers based on modern control techniques

Energy Technology Data Exchange (ETDEWEB)

Malik, O P; Chen, G P; Zhang, Y; El-Metwally, K [Calgary Univ., AB (Canada). Dept. of Electrical and Computer Engineering

1994-12-31

Developments in digital technology have made it feasible to develop and implement improved controllers based on sophisticated control techniques. Power system stabilizers based on adaptive control, fuzzy logic and artificial networks are being developed. Each of these control techniques possesses unique features and strengths. In this paper, the relative performance of power systems stabilizers based on adaptive control, fuzzy logic and neural network, both in simulation studies and real time tests on a physical model of a power system, is presented and compared to that of a fixed parameter conventional power system stabilizer. (author) 16 refs., 45 figs., 3 tabs.

Evaluation of preparation methods for MS-based analysis of intestinal epithelial cell proteomes

DEFF Research Database (Denmark)

Hesselager, Marianne Overgaard; Codrea, Marius Cosmin; Bendixen, Emøke

2015-01-01

analyzed by LC and electrospray QTOF-MS. The methods were evaluated according to efficiency, purity, transmembrane protein recovery, as well as for suitability to large-scale preparations. Our data clearly demonstrate that mucosal shaving is by far the best-suited method for in-depth MS analysis in terms...... are low in abundance, and large amounts of sample is needed for their preparation and for undertaking MS-based analysis. The aim of this study was to evaluate three different methods for isolation and preparation of pig intestinal epithelial cells for MS-based analysis of the proteome. Samples were...... of ease and speed of sample preparation, as well as protein recovery. In comparison, more gentle methods where intestinal epithelial cells are harvested by shaking are more time consuming, result in lower protein yield, and are prone to increased technical variation due to multiple steps involved....

A linac-based stereotactic irradiation technique of uveal melanoma

International Nuclear Information System (INIS)

Dieckmann, Karin; Bogner, Joachim; Georg, Dietmar; Zehetmayer, Martin; Kren, Gerhard; Poetter, Richard

2001-01-01

Purpose: To describe a stereotactic irradiation technique for uveal melanomas performed at a linac, based on a non-invasive eye fixation and eye monitoring system. Methods: For eye immobilization a light source system is integrated in a standard stereotactic mask system in front of the healthy eye: During treatment preparation (computed tomography/magnetic resonance imaging) as well as for treatment delivery, patients are instructed to gaze at the fixation light source. A mini-video camera monitors the pupil center position of the diseased eye. For treatment planning and beam delivery standard stereotactic radiotherapy equipment is used. If the pupil center deviation from a predefined 'zero-position' exceeds 1 mm (for more than 2 s), treatment delivery is interrupted. Between 1996 and 1999 60 patients with uveal melanomas, where (i) tumor height exceeded 7 mm, or (ii) tumor height was more than 3 mm, and the central tumor distance to the optic disc and/or the macula was less than 3 mm, have been treated. A total dose of 60 or 70 Gy has been given in 5 fractions within 10 days. Results: The repositioning accuracy in the mask system is 0.47±0.36 mm in rostral-occipital direction, 0.75±0.52 mm laterally, and 1.12±0.96 mm in vertical direction. An eye movement analysis performed for 23 patients shows a pupil center deviation from the 'zero' position<1 mm in 91% of all cases investigated. In a theoretical analysis, pupil center deviations are correlated with GTV 'movements'. For a pupil center deviation of 1 mm (rotation of the globe of 5 degree sign ) the GTV is still encompassed by the 80% isodose in 94%. Conclusion: For treatments of uveal melanomas, linac-based stereotactic radiotherapy combined with a non-invasive eye immobilization and monitoring system represents a feasible, accurate and reproducible method. Besides considerable technical requirements, the complexity of the treatment technique demands an interdisciplinary team continuously dedicated to this

Preparation of synthetic standard minerals

International Nuclear Information System (INIS)

Herrick, C.C.; Bustamante, S.J.; Charls, R.W.; Cowan, R.E.; Hakkila, E.A.; Hull, D.E.; Olinger, B.W.; Roof, R.B.; Sheinberg, H.; Herrick, G.C.

1978-01-01

A number of techniques for synthetic mineral preparations have been examined. These techniques include hot-pressing in graphite dies at moderate pressures, high-pressure, high-temperature synthesis in a piston and cylinder apparatus, isostatic pressing under helium gas pressures, hydrous mineral preparations using water as the pressure medium, explosion-generated shock waves, and radiofrequency heating. Minerals suitable for equation-of-state studies (three-inch, high-density discs), for thermodynamic property determinations (low-density powders) and for microprobe standards (fusion-cast microbeads) have been prepared. Mechanical stress-strain calculations in the piston-cylinder apparatus have been initiated and their integration with thermal stress calculations is currently under investigation

Improvement on preparation of PS microshells by microencapsulation

International Nuclear Information System (INIS)

Du Kai; You Dan; Zhang Lin; Zhou Lan; Lin Bo

1998-01-01

Density-matched microencapsulation technique was presented. Concentricity, sphericity of microshells prepared by the technique was typically more than 98%, 99% respectively. Reduction of vacuole in the wall and preparation of large diameter microshells were also discussed

Analysis of degradation in nickel-based alloys using focused ion beam imaging and specimen preparation combined with analytical electron microscopy

International Nuclear Information System (INIS)

Phaneuf, M.W.; Botton, G.A.

2002-01-01

Focused ion beam (FIB) microscopes have become well-established in the semiconductor industry during the past decade, and are rapidly gaining attention in the field of materials science, both as a tool for producing site specific, parallel sided transmission electron microscope (TEM) specimens and as stand alone specimen preparation and imaging systems. FIB secondary electron imaging (SEI) of nickel-based alloys, such as commercially produced Alloy 600 (approximately Ni 15Cr 10Fe 0.5C), has been demonstrated to show a high degree of sensitivity to the presence of deformation in the alloy, and FIB secondary ion imaging (SII) is particularly useful for identifying the presence of grain boundary corrosion, as secondary ion yields from metallic specimens can increase by three orders of magnitude in the presence of oxygen. This 'oxygen enhanced yield', makes FIB SII ideal for detection of corrosion at grain boundaries down to thicknesses of only a few tens of nanometers. Historically, while TEM has been considered the tool of choice for high resolution chemical and crystallographic analysis of specimens, the technique has suffered from difficulties in producing suitable samples from site-specific areas with a high probability of success. The advent of FIB specimen preparation for TEM has largely changed that. FIB imaging can be combined with FIB 'nano-machining' techniques to produce site-specific, parallel sided TEM specimens well-suited to analytical electron microscopy (AEM) analyses in the TEM, including electron energy loss spectroscopy (EELS), energy dispersive x-ray spectroscopy (EDX) and electron diffraction. When combined with new FIB-based methodologies for surveying large areas to exactly select the regions of interest, such as crack tips or the maximum extent of penetration of intergranular attack (IGA), subsequent FIB TEM specimen preparation and TEM analysis unite to produce a powerful tool to study these phenomena. Examples of these applications of FIB

Characterization and evaluation of 5-fluorouracil-loaded solid lipid nanoparticles prepared via a temperature-modulated solidification technique.

Science.gov (United States)

Patel, Meghavi N; Lakkadwala, Sushant; Majrad, Mohamed S; Injeti, Elisha R; Gollmer, Steven M; Shah, Zahoor A; Boddu, Sai Hanuman Sagar; Nesamony, Jerry

2014-12-01

The aim of this research was to advance solid lipid nanoparticle (SLN) preparation methodology by preparing glyceryl monostearate (GMS) nanoparticles using a temperature-modulated solidification process. The technique was reproducible and prepared nanoparticles without the need of organic solvents. An anticancer agent, 5-fluorouracil (5-FU), was incorporated in the SLNs. The SLNs were characterized by particle size analysis, zeta potential analysis, differential scanning calorimetry (DSC), infrared spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), drug encapsulation efficiency, in vitro drug release, and in vitro cell viability studies. Particle size of the SLN dispersion was below 100 nm, and that of redispersed lyophilizates was ~500 nm. DSC and infrared spectroscopy suggested that the degree of crystallinity did not decrease appreciably when compared to GMS. TEM and AFM images showed well-defined spherical to oval particles. The drug encapsulation efficiency was found to be approximately 46%. In vitro drug release studies showed that 80% of the encapsulated drug was released within 1 h. In vitro cell cultures were biocompatible with blank SLNs but demonstrated concentration-dependent changes in cell viability to 5-FU-loaded SLNs. The 5-FU-loaded SLNs can potentially be utilized in an anticancer drug delivery system.

Characterization of PE-g-HEMA films prepared by gamma irradiation through nuclear microprobe techniques

International Nuclear Information System (INIS)

Ferreira, L.M.; Rodrigues, P.A.; Falcao, A.N.; Leal, J.P.

2011-01-01

Complete text of publication follows. The functional success of a copolymer as biomaterial depends fundamentally on their mechanical properties (stemming from the material matrix) and on the characteristics of its surface. For biomedical applications, among all the other important properties, the biocompatibility of the surface acquires extreme importance and can dictate its rejection. One of the issues regarding biocompatibility is cytotoxicity which strongly depends on the contamination level at surface. Ion beam analysis techniques associated to Nuclear Microprobe (PIXE, RBS and STIM) allows a rigorous and precise analysis of the concentration (ppm) and distribution of elements contamination, and may also provide information on its near-surface structure. In this work PE-g-HEMA films with different grafting yields were prepared by mutual gamma irradiation at a 60 Co source and were analyzed through nuclear microprobe. Data collected allowed the qualitative and quantitative evaluation of contaminants distribution observed in the different samples as well as the clarification of some processes occurred during the copolymerization reaction. Qualitative analysis showed a random and no homogeneous distribution of the contaminant elements, independent of the grafting degree, suggesting the existence of several sources of contamination at different stages of their preparation. Results also suggest that this 'phased' contamination occurs simultaneously with mechanisms of agglomeration/entrapment of impurities during the gamma induced copolymerization reaction. Moreover, quantitative data showed that all contaminants found in the copolymeric films are natural contaminants of their reagents of preparation, although at concentrations without toxicological hazard, which points to a low cytotoxic potential. The combined analysis of these data with data from SEM and AFM allowed a better understanding of the surface structure and other properties already observed in these

Proteomic Challenges: Sample Preparation Techniques for Microgram-Quantity Protein Analysis from Biological Samples

Directory of Open Access Journals (Sweden)

Peter Feist

2015-02-01

Full Text Available Proteins regulate many cellular functions and analyzing the presence and abundance of proteins in biological samples are central focuses in proteomics. The discovery and validation of biomarkers, pathways, and drug targets for various diseases can be accomplished using mass spectrometry-based proteomics. However, with mass-limited samples like tumor biopsies, it can be challenging to obtain sufficient amounts of proteins to generate high-quality mass spectrometric data. Techniques developed for macroscale quantities recover sufficient amounts of protein from milligram quantities of starting material, but sample losses become crippling with these techniques when only microgram amounts of material are available. To combat this challenge, proteomicists have developed micro-scale techniques that are compatible with decreased sample size (100 μg or lower and still enable excellent proteome coverage. Extraction, contaminant removal, protein quantitation, and sample handling techniques for the microgram protein range are reviewed here, with an emphasis on liquid chromatography and bottom-up mass spectrometry-compatible techniques. Also, a range of biological specimens, including mammalian tissues and model cell culture systems, are discussed.

Proteomic Challenges: Sample Preparation Techniques for Microgram-Quantity Protein Analysis from Biological Samples

Science.gov (United States)

Feist, Peter; Hummon, Amanda B.

2015-01-01

Proteins regulate many cellular functions and analyzing the presence and abundance of proteins in biological samples are central focuses in proteomics. The discovery and validation of biomarkers, pathways, and drug targets for various diseases can be accomplished using mass spectrometry-based proteomics. However, with mass-limited samples like tumor biopsies, it can be challenging to obtain sufficient amounts of proteins to generate high-quality mass spectrometric data. Techniques developed for macroscale quantities recover sufficient amounts of protein from milligram quantities of starting material, but sample losses become crippling with these techniques when only microgram amounts of material are available. To combat this challenge, proteomicists have developed micro-scale techniques that are compatible with decreased sample size (100 μg or lower) and still enable excellent proteome coverage. Extraction, contaminant removal, protein quantitation, and sample handling techniques for the microgram protein range are reviewed here, with an emphasis on liquid chromatography and bottom-up mass spectrometry-compatible techniques. Also, a range of biological specimens, including mammalian tissues and model cell culture systems, are discussed. PMID:25664860

Proteomic challenges: sample preparation techniques for microgram-quantity protein analysis from biological samples.

Science.gov (United States)

Feist, Peter; Hummon, Amanda B

2015-02-05

Proteins regulate many cellular functions and analyzing the presence and abundance of proteins in biological samples are central focuses in proteomics. The discovery and validation of biomarkers, pathways, and drug targets for various diseases can be accomplished using mass spectrometry-based proteomics. However, with mass-limited samples like tumor biopsies, it can be challenging to obtain sufficient amounts of proteins to generate high-quality mass spectrometric data. Techniques developed for macroscale quantities recover sufficient amounts of protein from milligram quantities of starting material, but sample losses become crippling with these techniques when only microgram amounts of material are available. To combat this challenge, proteomicists have developed micro-scale techniques that are compatible with decreased sample size (100 μg or lower) and still enable excellent proteome coverage. Extraction, contaminant removal, protein quantitation, and sample handling techniques for the microgram protein range are reviewed here, with an emphasis on liquid chromatography and bottom-up mass spectrometry-compatible techniques. Also, a range of biological specimens, including mammalian tissues and model cell culture systems, are discussed.

Practical techniques for pediatric computed tomography

International Nuclear Information System (INIS)

Fitz, C.R.; Harwood-Nash, D.C.; Kirks, D.R.; Kaufman, R.A.; Berger, P.E.; Kuhn, J.P.; Siegel, M.J.

1983-01-01

Dr. Donald Kirks has assembled this section on Practical Techniques for Pediatric Computed Tomography. The material is based on a presentation in the Special Interest session at the 25th Annual Meeting of the Society for Pediatric Radiology in New Orleans, Louisiana, USA in 1982. Meticulous attention to detail and technique is required to ensure an optimal CT examination. CT techniques specifically applicable to infants and children have not been disseminated in the radiology literature and in this respect it may rightly be observed that ''the child is not a small adult''. What follows is a ''cookbook'' prepared by seven participants and it is printed in Pediatric Radiology, in outline form, as a statement of individual preferences for pediatric CT techniques. This outline gives concise explanation of techniques and permits prompt dissemination of information. (orig.)

Preparation of 3D graphene-based architectures and their applications in supercapacitors

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Zhuxian Yang

2015-12-01

Full Text Available Three dimensional (3D graphene-based architectures such as 3D graphene-based hydrogels, aerogels, foams, and sponges have attracted huge attention owing to the combination of the structural interconnectivities and the outstanding properties of graphene which offer these interesting structures with low density, high porosity, large surface area, stable mechanical properties, fast mass and electron transport. They have been extensively studied for a wide range of applications including capacitors, batteries, sensors, catalyst, etc. There are several reviews focusing on the 3D graphene-based architectures and their applications. In this work, we only summarise the latest development on the preparation of 3D graphene-based architectures and their applications in supercapacitors, with emphasis on the preparation strategies.

Contests versus Norms: Implications of Contest-Based and Norm-Based Intervention Techniques.

Science.gov (United States)

Bergquist, Magnus; Nilsson, Andreas; Hansla, André

2017-01-01

Interventions using either contests or norms can promote environmental behavioral change. Yet research on the implications of contest-based and norm-based interventions is lacking. Based on Goal-framing theory, we suggest that a contest-based intervention frames a gain goal promoting intensive but instrumental behavioral engagement. In contrast, the norm-based intervention was expected to frame a normative goal activating normative obligations for targeted and non-targeted behavior and motivation to engage in pro-environmental behaviors in the future. In two studies participants ( n = 347) were randomly assigned to either a contest- or a norm-based intervention technique. Participants in the contest showed more intensive engagement in both studies. Participants in the norm-based intervention tended to report higher intentions for future energy conservation (Study 1) and higher personal norms for non-targeted pro-environmental behaviors (Study 2). These findings suggest that contest-based intervention technique frames a gain goal, while norm-based intervention frames a normative goal.

Contests versus Norms: Implications of Contest-Based and Norm-Based Intervention Techniques

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Magnus Bergquist

2017-11-01

Full Text Available Interventions using either contests or norms can promote environmental behavioral change. Yet research on the implications of contest-based and norm-based interventions is lacking. Based on Goal-framing theory, we suggest that a contest-based intervention frames a gain goal promoting intensive but instrumental behavioral engagement. In contrast, the norm-based intervention was expected to frame a normative goal activating normative obligations for targeted and non-targeted behavior and motivation to engage in pro-environmental behaviors in the future. In two studies participants (n = 347 were randomly assigned to either a contest- or a norm-based intervention technique. Participants in the contest showed more intensive engagement in both studies. Participants in the norm-based intervention tended to report higher intentions for future energy conservation (Study 1 and higher personal norms for non-targeted pro-environmental behaviors (Study 2. These findings suggest that contest-based intervention technique frames a gain goal, while norm-based intervention frames a normative goal.

Patient preparation for intravenous urography: are we practising evidence-based medicine?

International Nuclear Information System (INIS)

Singh, S.; Reddicliffe, N.; Parker, D.A.

2008-01-01

Aim: To identify the current practice of patient preparation prior to intravenous urography (IVU) in England and Wales. Methods: Seventy-two hospitals were contacted to request details regarding the duration of fluid restriction, adherence to a low-residue diet, or use of laxatives for patient preparation before IVU examinations. Results: Results showed that out of 45 hospitals that still use IVU, only six (13.3%) did not follow a patient-preparation regime. The vast majority of the hospitals contacted (87.6%), implemented either fluid and/or food restriction, or prescribed laxatives. The duration of fluid and food restriction varied from 2-12 h duration, and some departments advocated 48 h of laxatives. Conclusion: A large proportion of hospitals are not practising evidence-based medicine in relation to IVU, and we suggest that the practice of patient preparation should be abandoned

Integration of Computational and Preparative Techniques to Demonstrate Physical Organic Concepts in Synthetic Organic Chemistry: An Example Using Diels-Alder Reaction

Science.gov (United States)

Palmer, David R. J.

2004-01-01

The Diels-Alder reaction is used as an example for showing the integration of computational and preparative techniques, which help in demonstrating the physical organic concepts in synthetic organic chemistry. These experiments show that the students should not accept the computational results without questioning them and in many Diels-Alder…

Preparation of sustained-release coated particles by novel microencapsulation method using three-fluid nozzle spray drying technique.

Science.gov (United States)

Kondo, Keita; Niwa, Toshiyuki; Danjo, Kazumi

2014-01-23

We prepared sustained-release microcapsules using a three-fluid nozzle (3N) spray drying technique. The 3N has a unique, three-layered concentric structure composed of inner and outer liquid nozzles, and an outermost gas nozzle. Composite particles were prepared by spraying a drug suspension and an ethylcellulose solution via the inner and outer nozzles, respectively, and mixed at the nozzle tip (3N-PostMix). 3N-PostMix particles exhibited a corrugated surface and similar contact angles as ethylcellulose bulk, thus suggesting encapsulation with ethylcellulose, resulting in the achievement of sustained release. To investigate the microencapsulation process via this approach and its usability, methods through which the suspension and solution were sprayed separately via two of the four-fluid nozzle (4N) (4N-PostMix) and a mixture of the suspension and solution was sprayed via 3N (3N-PreMix) were used as references. It was found that 3N can obtain smaller particles than 4N. The results for contact angle and drug release corresponded, thus suggesting that 3N-PostMix particles are more effectively coated by ethylcellulose, and can achieve higher-level controlled release than 4N-PostMix particles, while 3N-PreMix particles are not encapsulated with pure ethylcellulose, leading to rapid release. This study demonstrated that the 3N spray drying technique is useful as a novel microencapsulation method. Copyright © 2013 Elsevier B.V. All rights reserved.

Self-Supporting, Hydrophobic, Ionic Liquid-Based Reference Electrodes Prepared by Polymerization-Induced Microphase Separation.

Science.gov (United States)

Chopade, Sujay A; Anderson, Evan L; Schmidt, Peter W; Lodge, Timothy P; Hillmyer, Marc A; Bühlmann, Philippe

2017-10-27

Interfaces of ionic liquids and aqueous solutions exhibit stable electrical potentials over a wide range of aqueous electrolyte concentrations. This makes ionic liquids suitable as bridge materials that separate in electroanalytical measurements the reference electrode from samples with low and/or unknown ionic strengths. However, methods for the preparation of ionic liquid-based reference electrodes have not been explored widely. We have designed a convenient and reliable synthesis of ionic liquid-based reference electrodes by polymerization-induced microphase separation. This technique allows for a facile, single-pot synthesis of ready-to-use reference electrodes that incorporate ion conducting nanochannels filled with either 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-dodecyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide as ionic liquid, supported by a mechanically robust cross-linked polystyrene phase. This synthesis procedure allows for the straightforward design of various reference electrode geometries. These reference electrodes exhibit a low resistance as well as good reference potential stability and reproducibility when immersed into aqueous solutions varying from deionized, purified water to 100 mM KCl, while requiring no correction for liquid junction potentials.

Preparation and stability investigation of tamsulosin hydrochloride sustained release pellets containing acrylic resin polymers with two different techniques

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Rui Fan

2017-03-01

Full Text Available The objective of this study was to prepare tamsulosin hydrochloride-sustained release (TSH-SR pellets which showed good release stability with frame-controlled method. TSH was added to Eudragit®NE30D and Eudragit®L30D-55 polymers to form drug-loaded inner core. Afterwards, enteric Eudragit®L30D-55 polymer was modified on the surface of it to the final product. Dissolution studies showed that TSH-SR pellets were more stable during the coating process, different curing temperatures and storage conditions compared with TSH pellets produced by film-controlled technique. Appearances and glass transition temperatures (Tgs of free films and surface morphologies observed by scanning electron microscopy (SEM of blank sustained release pellets prepared by different ratios of Eudragit®NE30D and Eudragit®L30D-55 further indicated that temperature and relative humidity (RH were the key factors when Eudragit®NE30D blended with Eudragit®L30D-55 were applied to sustained/controlled release preparations. In addition, SEM identified the surface morphologies of TSH-SR pellets before and after dissolution, which showed intact surface structure and great correlation with release curve respectively.

Microstructures and Mechanical Properties of Co-Cr Dental Alloys Fabricated by Three CAD/CAM-Based Processing Techniques

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Hae Ri Kim

2016-07-01

Full Text Available The microstructures and mechanical properties of cobalt-chromium (Co-Cr alloys produced by three CAD/CAM-based processing techniques were investigated in comparison with those produced by the traditional casting technique. Four groups of disc- (microstructures or dumbbell- (mechanical properties specimens made of Co-Cr alloys were prepared using casting (CS, milling (ML, selective laser melting (SLM, and milling/post-sintering (ML/PS. For each technique, the corresponding commercial alloy material was used. The microstructures of the specimens were evaluated via X-ray diffractometry, optical and scanning electron microscopy with energy-dispersive X-ray spectroscopy, and electron backscattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test according to ISO 22674 (n = 6. The microstructure of the alloys was strongly influenced by the manufacturing processes. Overall, the SLM group showed superior mechanical properties, the ML/PS group being nearly comparable. The mechanical properties of the ML group were inferior to those of the CS group. The microstructures and mechanical properties of Co-Cr alloys were greatly dependent on the manufacturing technique as well as the chemical composition. The SLM and ML/PS techniques may be considered promising alternatives to the Co-Cr alloy casting process.

Nasal base narrowing: the combined alar base excision technique.

Science.gov (United States)

Foda, Hossam M T

2007-01-01

To evaluate the role of the combined alar base excision technique in narrowing the nasal base and correcting excessive alar flare. The study included 60 cases presenting with a wide nasal base and excessive alar flaring. The surgical procedure combined an external alar wedge resection with an internal vestibular floor excision. All cases were followed up for a mean of 32 (range, 12-144) months. Nasal tip modification and correction of any preexisting caudal septal deformities were always completed before the nasal base narrowing. The mean width of the external alar wedge excised was 7.2 (range, 4-11) mm, whereas the mean width of the sill excision was 3.1 (range, 2-7) mm. Completing the internal excision first resulted in a more conservative external resection, thus avoiding any blunting of the alar-facial crease. No cases of postoperative bleeding, infection, or keloid formation were encountered, and the external alar wedge excision healed with an inconspicuous scar that was well hidden in the depth of the alar-facial crease. Finally, the risk of notching of the alar rim, which can occur at the junction of the external and internal excisions, was significantly reduced by adopting a 2-layered closure of the vestibular floor (P = .01). The combined alar base excision resulted in effective narrowing of the nasal base with elimination of excessive alar flare. Commonly feared complications, such as blunting of the alar-facial crease or notching of the alar rim, were avoided by using simple modifications in the technique of excision and closure.

Simulation-based optimization parametric optimization techniques and reinforcement learning

CERN Document Server

Gosavi, Abhijit

2003-01-01

Simulation-Based Optimization: Parametric Optimization Techniques and Reinforcement Learning introduces the evolving area of simulation-based optimization. The book's objective is two-fold: (1) It examines the mathematical governing principles of simulation-based optimization, thereby providing the reader with the ability to model relevant real-life problems using these techniques. (2) It outlines the computational technology underlying these methods. Taken together these two aspects demonstrate that the mathematical and computational methods discussed in this book do work. Broadly speaking, the book has two parts: (1) parametric (static) optimization and (2) control (dynamic) optimization. Some of the book's special features are: *An accessible introduction to reinforcement learning and parametric-optimization techniques. *A step-by-step description of several algorithms of simulation-based optimization. *A clear and simple introduction to the methodology of neural networks. *A gentle introduction to converg...

IMAGE ANALYSIS BASED ON EDGE DETECTION TECHNIQUES

Institute of Scientific and Technical Information of China (English)

纳瑟; 刘重庆

2002-01-01

A method that incorporates edge detection technique, Markov Random field (MRF), watershed segmentation and merging techniques was presented for performing image segmentation and edge detection tasks. It first applies edge detection technique to obtain a Difference In Strength (DIS) map. An initial segmented result is obtained based on K-means clustering technique and the minimum distance. Then the region process is modeled by MRF to obtain an image that contains different intensity regions. The gradient values are calculated and then the watershed technique is used. DIS calculation is used for each pixel to define all the edges (weak or strong) in the image. The DIS map is obtained. This help as priority knowledge to know the possibility of the region segmentation by the next step (MRF), which gives an image that has all the edges and regions information. In MRF model,gray level l, at pixel location i, in an image X, depends on the gray levels of neighboring pixels. The segmentation results are improved by using watershed algorithm. After all pixels of the segmented regions are processed, a map of primitive region with edges is generated. The edge map is obtained using a merge process based on averaged intensity mean values. A common edge detectors that work on (MRF) segmented image are used and the results are compared. The segmentation and edge detection result is one closed boundary per actual region in the image.

A novel preparation technique of red (sparkling wine for protein analysis

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Elisabeth I. Vogt

2016-06-01

Full Text Available Despite their low concentration, proteins can influence several key enological parameters such as foam stability or haze formation in (sparkling wine. Most studies focus on white (sparkling wine since the higher content of phenolic compounds in red wines impairs proteomic research. The aim of the study was the development of a method for the preparation of red (sparkling wine proteins for proteomic analysis. Three methods of sample preparation were assessed on silver stained SDS-PAGE gels and with MALDI-TOF MS. Our new method was highly suitable for the preparation of proteins for the aforementioned applications. The results showed a substantial increase in signal intensity with a simultaneous decrease in background noise. The preparation protocol consists of (i dialysis and freeze drying of the sample, (ii removal of phenolic compounds by water-saturated phenol and (iii protein precipitation by addition of ammonium acetate. Employment of this method followed by SDS-PAGE analysis allowed for silver stained gels with diminished background or streaking and clearly resolved protein bands. Analysis of spectra obtained from samples prepared according to the proposed protocol showed increased intensity and signal-to-noise ratio in MALDI-TOF MS. Furthermore it was demonstrated that this method can be applied to various kinds of grape products.

Preparation, Characterization, and Electrochromic Properties of Nanocellulose-Based Polyaniline Nanocomposite Films.

Science.gov (United States)

Zhang, Sihang; Sun, Gang; He, Yongfeng; Fu, Runfang; Gu, Yingchun; Chen, Sheng

2017-05-17

On the basis of nanocellulose obtained by acidic swelling and ultrasonication, rodlike nanocellulose/polyaniline nanocomposites with a core-shell structure have been prepared via in situ polymerization. Compared to pure polyaniline, the nanocomposites show superior film-forming properties, and the prepared nanocomposite films demonstrate excellent electrochemical and electrochromic properties in electrolyte solution. Nanocomposite films, especially the one prepared with 40% polyaniline coated nanocomposite, exhibited faster response time (1.5 s for bleaching and 1.0 s for coloring), higher optical contrast (62.9%), higher coloration efficiency (206.2 cm 2 /C), and more remarkable switching stability (over 500 cycles). These novel nanocellulose-based nanorod network films are promising novel electrochromic materials with excellent properties.

In vitro evaluation of mucoadhesive vaginal tablets of antifungal drugs prepared with thiolated polymer and development of a new dissolution technique for vaginal formulations.

Science.gov (United States)

Baloglu, Esra; Ay Senyıgıt, Zeynep; Karavana, Sinem Yaprak; Vetter, Anja; Metın, Dilek Yesim; Hilmioglu Polat, Suleyha; Guneri, Tamer; Bernkop-Schnurch, Andreas

2011-01-01

The main objective of this work was to develop antifungal matrix tablet for vaginal applications using mucoadhesive thiolated polymer. Econazole nitrate (EN) and miconazole nitrate (MN) were used as antifungal drugs to prepare the vaginal tablet formulations. Thiolated poly(acrylic acid)-cysteine (PAA-Cys) conjugate was synthesized by the covalent attachment of L-cysteine to PAA with the formation of amide bonds between the primary amino group of L-cysteine and the carboxylic acid group of the polymer. Vaginal mucoadhesive matrix tablets were prepared by direct compression technique. The investigation focused on the influence of modified polymer on water uptake behavior, mucoadhesive property and release rate of drug. Thiolated polymer increased the water uptake ratio and mucoadhesive property of the formulations. A new simple dissolution technique was developed to simulate the vaginal environment for the evaluation of release behavior of vaginal tablets. In this technique, daily production amount and rate of the vaginal fluid was used without any rotational movement. The drug release was found to be slower from PAA-Cys compared to that from PAA formulations. The similarity study results confirmed that the difference in particle size of EN and MN did not affect their release profile. The release process was described by plotting the fraction released drug versus time and n fitting data to the simple exponential model: M(t)/M(∞)=kt(n). The release kinetics were determined as Super Case II for all the formulations prepared with PAA or PAA-Cys. According to these results the mucoadhesive vaginal tablet formulations prepared with PAA-Cys represent good example for delivery systems which prolong the residence time of drugs at the vaginal mucosal surface.

[Microfungicid--a preparation based on trichoderma viride for plant diseases control].

Science.gov (United States)

Kolombet, L V; Zhigletsova, S K; Derbyshev, V V; Ezhov, D V; Kosareva, N I; Bystrova, E V

2001-01-01

A technology was designed for manufacturing a preparation based on Trichoderma viride Pers ex S.F. Gray that strongly suppresses the development of causative agents of certain plant diseases and displays a growth-stimulating activity. Cultivation of the strain in a liquid medium for 18-24 h produced up to 60 g dry biomass per liter nutrient medium. A marketable form created in this work conserves the activity of the mycelial preparation for six months. The preparation is compatible with insecticides (carbofos, vismetrin, talstar, and applaud) and certain fungicides (such as baitan). Tests performed with the liquid form of Mycofungicid (seeds were treated with this preparation at a dose of 20-30 g per metric ton before sowing) showed its high efficiency in protecting cereal crops from plant pathogens. The incidence of plant diseases decreased by 65%, and crop yields increased by 15-20%.

Sample preparation method for induced mutation on orchid

International Nuclear Information System (INIS)

Suhaimi Musa; Sakinah Ariffin

2005-01-01

Studies on the induction of mutation in Dendrobium orchid at MINT has produced a number of new orchid mutant cultivars. Tissue culture techniques on orchid seeds and meristem cloning are employed in preparing the samples for the mutation induction. Solid medium based on the Murashige and Skoog (1962) and liquid medium based on Vacin and Went (1949) were found to be suitable in producing protocorm like bodies (PLBs) that are required for the irradiation treatment. (Author)

Carbon storage as affected by different site preparation techniques two years after mixed forest stand installation

Energy Technology Data Exchange (ETDEWEB)

Fonseca, F.; Figueiredo, T. de; Martins, A.

2014-06-01

Aim of study: This study aims at evaluating the impact of site preparation techniques prior to plantation on carbon storage and distribution in a young mixed stand of Pseudotsuga menziesii (PM) and Castanea sativa (CS). Area of study: The experimental field was established near Macedo de Cavaleiros, Northern Portugal, at 700 m elevation, mean annual temperature 12 degree centigrade and mean annual rainfall 678 mm. Material and methods: The experimental layout includes three replicates, where the different treatments corresponding to different tillage intensities were randomly distributed (high, moderate and slight intensity), in plots with an area of 375 m{sup 2} each. Twenty six months after forest stand installation, samples of herbaceous vegetation (0.49 m{sup 2} quadrat), forest species (8 PM and 8 CS) and mineral soil (at 0-5, 5-15, 15-30 and 30-60 cm depth) were collected in 15 randomly selected points in each treatment, processed in laboratory and analyzed for carbon by elemental carbon analyzer. Main results: The results obtained showed that: (i) more than 90% of the total carbon stored in the system is located in the soil, increasing in depth with tillage intensity; (ii) the contribution of herbaceous vegetation and related roots to the carbon storage is very low; (iii) the amount of carbon per tree is higher in CS than in PM; (iv) the global carbon storage was affected by soil tillage generally decreasing with the increase of tillage intensity. Accordingly, carbon storage capacity as affected by the application of different site preparation techniques should be a decision support tool in afforestation schemes. (Author)

A Method for Microalgae Proteomics Analysis Based on Modified Filter-Aided Sample Preparation.

Science.gov (United States)

Li, Song; Cao, Xupeng; Wang, Yan; Zhu, Zhen; Zhang, Haowei; Xue, Song; Tian, Jing

2017-11-01

With the fast development of microalgal biofuel researches, the proteomics studies of microalgae increased quickly. A filter-aided sample preparation (FASP) method is widely used proteomics sample preparation method since 2009. Here, a method of microalgae proteomics analysis based on modified filter-aided sample preparation (mFASP) was described to meet the characteristics of microalgae cells and eliminate the error caused by over-alkylation. Using Chlamydomonas reinhardtii as the model, the prepared sample was tested by standard LC-MS/MS and compared with the previous reports. The results showed mFASP is suitable for most of occasions of microalgae proteomics studies.

Facile preparation of luminescent and intelligent gold nanodots based on supramolecular self-assembly

International Nuclear Information System (INIS)

Shi Yunfeng; Li Sujuan; Zhou Yahui; Zhai Qingpan; Hu Mengyue; Cai Fensha; Du Jimin; Liang Jiamiao; Zhu Xinyuan

2012-01-01

A new strategy for preparing luminescent and intelligent gold nanodots based on supramolecular self-assembly is described in this paper. The supramolecular self-assembly was initiated through electrostatic interactions and ion pairing between palmitic acid and hyperbranched poly(ethylenimine). The resulting structures not only have the dynamic reversible properties of supramolecules but also possess torispherical and highly branched architectures. Thus they can be regarded as a new kind of ideal nanoreactor for preparing intelligent Au nanodots. By preparing Au nanodots within this kind of supramolecular self-assembly, the environmental sensitivity of intelligent polymers and the optical, electrical properties of Au nanodots can be combined, endowing the Au nanodots with intelligence. In this paper, a supramolecular self-assembly process based on dendritic poly(ethylenimine) and palmitic acid was designed and then applied to prepare fluorescent and size-controlled Au nanodots. The pH response of Au nanodots embodied by phase transfer from oil phase to water phase was also investigated. (paper)

APPLICABILITY OF CONSOLIDATED TECHNIQUES IN THE VIEW OF ROMANIAN ACCOUNTING REGULATIONS

Directory of Open Access Journals (Sweden)

Cristina Rosu

2016-06-01

Full Text Available The accounting regulations are more and more interested in groups of companies. In some cases, these regulations require for preparing the consolidated financial statements. This is the task of the parent company who keeps the consolidated accounts. To accomplish its goals, the consolidated accounting uses a couple of, so-called, consolidation techniques. These are applied in the case of groups of companies with a complex structure. Their goal is to elaborate the consolidated financial statements using a set of methods and empirical skills. In this article we synthetize and apply the consolidation techniques in the view of Romanian accounting regulations. The Romanian practice has revealed, especially, two techniques: one based on direct consolidation and another one based on multiple levels (phased consolidation. Therefore, this work regards only the technical side of consolidated accounting, accounting records being evaded. Furthermore, we focus only on the preparation of the consolidated balance sheet in the case of some hypothetical groups of companies.

Preparation and evaluation of tamsulosin hydrochloride sustained-release pellets modified by two-layered membrane techniques

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Jingmin Wang

2015-02-01

Full Text Available The aim of the present study was to develop tamsulosin hydrochloride sustained-release pellets using two-layered membrane techniques. Centrifugal granulator and fluidized-bed coater were employed to prepare drug-loaded pellets and to employ two-layered membrane coating respectively. The prepared pellets were evaluated for physicochemical characterization, subjected to differential scanning calorimetry (DSC and in vitro release of different pH. Different release models and scanning electron microscopy (SEM were utilized to analyze the release mechanism of Harnual® and home-made pellets. By comparing the dissolution profiles, the ratio and coating weight gain of Eudragit® NE30D and Eudragit® L30D55 which constitute the inside membrane were identified as 18:1 and 10%–11%. The coating amount of outside membrane containing Eudragit® L30D55 was determined to be 0.8%. The similarity factors (f2 of home-made capsule and commercially available product (Harnual® were above 50 in different dissolution media. DSC studies confirmed that drug and excipients had good compatibility and SEM photographs showed the similarities and differences of coating surface between Harnual® and self-made pellets before and after dissolution. According to Ritger-Peppas model, the two dosage form had different release mechanism.

Preparation and Property Recognition of Nimodipine Molecularly Imprinted Polymer

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Fei-fei CHEN

2015-09-01

Full Text Available Objective: To explore the application of molecular imprinting technique in the separation and detection of nimodipine. Methods: Methacrylic acid as functional monomer, pentaerythritol triacrylate as cross-linking agent were used to prepare molecularly imprinted polymer (MIP with the feature of specific recognition performance on imprinting molecule nimodipine under condition of template molecule nimodipine. The preparation conditions, recognition performance of MIP on nimodipine, different proportions of template molecule and functional monomer, the selectivity to other substrate, and the relationship between adsorption quantity (Q and time were observed. Results: MIP was prepared successfully bynimodipine as template and pentaerythritol triacrylate as cross-linking agent, with the feature of specific recognition performance on nimodipine. The static adsorption distribution coefficient (KD was 0.2264. The equation of Q and the concentration of substrate of template MIP was y = -0.21x+0.2204. Combining capacity of template molecule at the same concentration enhanced with the increasing proportion of functional monomer.Conclusion: Nimodipine MIP based on molecular imprinting technique may become a new approach to chiral separation for nimodipine.

Preparation and Characterization of Water-Based Nano-fluids for Nuclear Applications

International Nuclear Information System (INIS)

Williams, W.C.; Forrest, E.; Hu, L.W.; Buongiorno, J.

2006-01-01

As part of an effort to evaluate water-based nano-fluids for nuclear applications, preparation and characterization has been performed for nano-fluids being considered for MIT's nano-fluid heat transfer experiments. Three methods of generating these nano-fluids are available: creating them from chemical precipitation, purchasing the nano-particles in powder form and mixing them with the base fluid, and direct purchase of prepared nano-fluids. Characterization of nano-fluids includes colloidal stability, size distribution, concentration, and elemental composition. Quality control of the nano-fluids to be used for heat transfer testing is crucial; an exact knowledge of the fluid constituents is essential to uncovering mechanisms responsible for heat transport enhancement. Testing indicates that nano-fluids created by mixing a liquid with nano-particles in powder form are often not stable, although some degree of stabilization is obtainable with pH control and/or surfactant addition. Some commercially available prepared nano-fluids have been found to contain unacceptable levels of impurities and/or include a different weight percent of nano-particles compared to vendor specifications. Tools utilized to characterize and qualify nano-fluids for this study include neutron activation analysis (NAA), inductively-coupled plasma spectroscopy (ICP), transmission electron microscopy (TEM) imaging, thermogravimetric analysis (TGA) and dynamic light scattering (DLS). Preparation procedures and characterization results for selected nano-fluids will be discussed in detail. (authors)

Three-Dimensional Implant Positioning with a Piezosurgery Implant Site Preparation Technique and an Intraoral Surgical Navigation System: Case Report.

Science.gov (United States)

Pellegrino, Gerardo; Taraschi, Valerio; Vercellotti, Tomaso; Ben-Nissan, Besim; Marchetti, Claudio

This case report describes new implant site preparation techniques joining the benefits of using an intraoral navigation system to optimize three-dimensional implant site positioning in combination with an ultrasonic osteotomy. A report of five patients is presented, and the implant positions as planned in the navigation software with the postoperative scan image were compared. The preliminary results are useful, although further clinical studies with larger populations are needed to confirm these findings.

Current STR-based techniques in forensic science

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Phuvadol Thanakiatkrai

2013-01-01

Full Text Available DNA analysis in forensic science is mainly based on short tandem repeat (STR genotyping. The conventional analysis is a three-step process of DNA extraction, amplification and detection. An overview of various techniques that are currently in use and are being actively researched for STR typing is presented. The techniques are separated into STR amplification and detection. New techniques for forensic STR analysis focus on increasing sensitivity, resolution and discrimination power for suboptimal samples. These are achieved by shifting primer-binding sites, using high-fidelity and tolerant polymerases and applying novel methods to STR detection. Examples in which STRs are used in criminal investigations are provided and future research directions are discussed.

Electromembrane extraction as a rapid and selective miniaturized sample preparation technique for biological fluids

DEFF Research Database (Denmark)

Gjelstad, Astrid; Pedersen-Bjergaard, Stig; Seip, Knut Fredrik

2015-01-01

This special report discusses the sample preparation method electromembrane extraction, which was introduced in 2006 as a rapid and selective miniaturized extraction method. The extraction principle is based on isolation of charged analytes extracted from an aqueous sample, across a thin film....... Technical aspects of electromembrane extraction, important extraction parameters as well as a handful of examples of applications from different biological samples and bioanalytical areas are discussed in the paper....

Comparison of the Effect of Canal Preparation by Step Back Technique Using Hand Instruments and Gates Glidden Drills with ProTaper Universal Rotary System on the Root Resistance to Vertical Fracture

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A Abbaszadegan

2013-06-01

Full Text Available Introduction: Cleaning and shaping of the root canal system with an efficient and safe technique are the major goals of root canal treatment. The aim of this study was to compare the conventional root canal preparation technique by hand instruments and Gates Glidden drills with ProTaper Universal Rotary system on the root susceptibility to vertical fracture. Methods: Thirty extracted human mandibular premolars were randomly assigned to two groups. In group I, apical preparation was performed with k-files up to #40 utilizing step back technique and coronal flaring was done with Gates Glidden drills. In group II, ProTaper Universal Rotary instruments were used up to the file F4. All teeth were obturated with lateral compaction technique using gutta-percha and AH26 sealer. A simulated periodontal ligament was fabricated, and the teeth were mounted. A stainless steel finger spreader #35 was mounted in an Instron testing machine and the necessary load to cause a root fracture was inserted and recorded. The obtained data were analyzed statistically using T-test. Results: The force required to fracture was significantly lower for the roots prepared by ProTaper instruments in comparison with the specimens prepared by hand instruments and Gates Glidden drills (P< 0.001. Conclusion: Canal preparation with ProTaper rotary instruments can make the roots more susceptible to vertical fracture than traditional instrumentation with k-files and Gates Glidden drills.

GIS-based bivariate statistical techniques for groundwater potential ...

Indian Academy of Sciences (India)

Ali Haghizadeh

2017-11-23

Nov 23, 2017 ... regions. This study shows the potency of two GIS-based data driven ... growth of these tools has also prepared another ..... Urban. 30467. 3. 0.06. 0.20. 0.74. 0.80. −0.64. Distance from road ..... and artificial neural networks for potential groundwater .... ping: A case study at Mehran region, Iran; Catena 137.

Preparations based on minerals extracts of Calicotome villosa roots and bovine butyrate matter: Evaluation in vitro of their antifungal activity.

Science.gov (United States)

Barhouchi, B; Aouadi, S; Abdi, A

2017-06-01

The use of preparations based on minerals extracts of Calicotome villosa and butter is born from the misuse of drugs without specific microbiological analyzes. Seventeen different preparations were performed. The antibacterial and antifungal activities were determined on five bacteria and two fungi strains respectively. C. villosa ashes are obtained by incineration of roots plant at 498°C for 4hours. They are analyzed to determine the shape of the particles and the mineral constituents by scanning electronic microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques respectively. The effectiveness of preparations or tablets is measured in solid medium. It allows to measure the diameter of the inhibition zone for the antibacterial activity as well as the diameter of mycelia growth and the critical values (MIC, MFC, IC 50 and IC 90 ) for the antifungal activity. Finally, the results are compared to the activity of a commercial positive control aiming to give value of the observed activity. SEM observations reveal the presence of nanoparticles agglomerated with size of about 50nm. The EDX analyzes indicate the presence of Fe, Na, Al, Mg, Si, K, Ca, O 2 and C. Among all the results, the preparation (B s +A) or (B sd +A) can completely inhibit the growth of two fungal pathogens. The activity of the preparation is faced with the activity of the synthetic fungicide nystatin. The efficacy of the preparation (B s +A) or (B sd +A) is higher than that of nystatin against Aspergillus sp. and Fusarium sp. The preparation could serve as natural antifungal for the pharmaceutical industry. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Enhancement of Edge-based Image Quality Measures Using Entropy for Histogram Equalization-based Contrast Enhancement Techniques

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H. T. R. Kurmasha

2017-12-01

Full Text Available An Edge-based image quality measure (IQM technique for the assessment of histogram equalization (HE-based contrast enhancement techniques has been proposed that outperforms the Absolute Mean Brightness Error (AMBE and Entropy which are the most commonly used IQMs to evaluate Histogram Equalization based techniques, and also the two prominent fidelity-based IQMs which are Multi-Scale Structural Similarity (MSSIM and Information Fidelity Criterion-based (IFC measures. The statistical evaluation results show that the Edge-based IQM, which was designed for detecting noise artifacts distortion, has a Person Correlation Coefficient (PCC > 0.86 while the others have poor or fair correlation to human opinion, considering the Human Visual Perception (HVP. Based on HVP, this paper propose an enhancement to classic Edge-based IQM by taking into account the brightness saturation distortion which is the most prominent distortion in HE-based contrast enhancement techniques. It is tested and found to have significantly well correlation (PCC > 0.87, Spearman rank order correlation coefficient (SROCC > 0.92, Root Mean Squared Error (RMSE < 0.1054, and Outlier Ratio (OR = 0%.

Preparation of nanostructured ZrO2 thin films by using spray pyrolysis technique for gas sensing application

International Nuclear Information System (INIS)

Deshmukh, S.B.; Bari, R.H.; Jain, G.H.

2013-01-01

In present work the nano-structured pure ZrO 2 thin films were prepared using spray pyrolysis techniques. The aqueous solution of ZrCl 4 , was used as a precursor with flow rate controlled 5 mI/min. The films were synthesized on glass substrate between temperature 250-400℃ and subjected to different analytical characterization like SEM, XRD, TEM, FTIR, UV, TGA-DTA/DSC. The gas sensing performances of various gases were tested in different operating temperature range. The sensitivity, selectivity, response and recovery time for H 2 S gas was discussed. Also nano structured grain size discussed. (author)

An Observed Voting System Based On Biometric Technique

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B. Devikiruba

2015-08-01

Full Text Available ABSTRACT This article describes a computational framework which can run almost on every computer connected to an IP based network to study biometric techniques. This paper discusses with a system protecting confidential information puts strong security demands on the identification. Biometry provides us with a user-friendly method for this identification and is becoming a competitor for current identification mechanisms. The experimentation section focuses on biometric verification specifically based on fingerprints. This article should be read as a warning to those thinking of using methods of identification without first examine the technical opportunities for compromising mechanisms and the associated legal consequences. The development is based on the java language that easily improves software packages that is useful to test new control techniques.

Preparing data for analysis using microsoft Excel.

Science.gov (United States)

Elliott, Alan C; Hynan, Linda S; Reisch, Joan S; Smith, Janet P

2006-09-01

A critical component essential to good research is the accurate and efficient collection and preparation of data for analysis. Most medical researchers have little or no training in data management, often causing not only excessive time spent cleaning data but also a risk that the data set contains collection or recording errors. The implementation of simple guidelines based on techniques used by professional data management teams will save researchers time and money and result in a data set better suited to answer research questions. Because Microsoft Excel is often used by researchers to collect data, specific techniques that can be implemented in Excel are presented.

PVA/CM-chitosan/honey hydrogels prepared by using the combined technique of irradiation followed by freeze-thawing

Science.gov (United States)

Afshari, M. J.; Sheikh, N.; Afarideh, H.

2015-08-01

Hydrogels with three components, poly(vinyl alcohol) (PVA), carboxymethylate chitosan (CM-chitosan) and honey have been prepared by using radiation method and radiation followed by freeze-thawing cycles technique (combinational method). The solid concentration of the polymer solution is 15 wt% and the ratios of PVA/CM-chitosan/honey are 10/1.5/3.5, 10/2/3, 10/3/2, and 10/3.5/1.5. The applied irradiation doses are 25, 30 and 40 kGy. Various tests have been done to evaluate the hydrogel properties to produce materials to be used as wound dressing. The results show that combinational method improves the mechanical strength of hydrogels while it has no significant effect on the water evaporation rate of gels. The combinational method decreases the swelling of hydrogels significantly, albeit this parameter is still acceptable for wound dressing. Microbiological analyses show that the hydrogel prepared by both methods can protect the wound from Escherichia coli bacterial infection. The wound healing test shows the good performance of the gels in mice.

Improving the technical preparation of football players on the basis of the control of discriminative characteristics when performing combinations of techniques during a game

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Mitova Olena

2016-06-01

Full Text Available The paper examines the issue of improving the technical preparation of football players during initial basic training. A special attention is paid to the development and experimental substantiation of the methods of technical preparation of young football players in an annual cycle at the stage of initial basic training on the basis of the control of discriminative characteristics when performing inseparable combinations of techniques during a game. An attempt was made to uncover the underlying causes of a low technical preparedness of football players at different stages of multi-year training and to implement an integrated scientific approach to improvement of the process of technical preparation of 10-11 years old football players in an annual cycle at the stage of initial basic training on the basis of the control of discriminative characteristics when performing inseparable combinations of techniques during competitive activity, along with the peculiarities of psychophysical condition and a level of development of physical qualities. This approach in teaching technical skills will be of interest to specialists and coaches in football, since the pedagogical experiment has determined the effectiveness of the developed methodology.

A novel technique for extracting clouds base height using ground based imaging

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E. Hirsch

2011-01-01

Full Text Available The height of a cloud in the atmospheric column is a key parameter in its characterization. Several remote sensing techniques (passive and active, either ground-based or on space-borne platforms and in-situ measurements are routinely used in order to estimate top and base heights of clouds. In this article we present a novel method that combines thermal imaging from the ground and sounded wind profile in order to derive the cloud base height. This method is independent of cloud types, making it efficient for both low boundary layer and high clouds. In addition, using thermal imaging ensures extraction of clouds' features during daytime as well as at nighttime. The proposed technique was validated by comparison to active sounding by ceilometers (which is a standard ground based method, to lifted condensation level (LCL calculations, and to MODIS products obtained from space. As all passive remote sensing techniques, the proposed method extracts only the height of the lowest cloud layer, thus upper cloud layers are not detected. Nevertheless, the information derived from this method can be complementary to space-borne cloud top measurements when deep-convective clouds are present. Unlike techniques such as LCL, this method is not limited to boundary layer clouds, and can extract the cloud base height at any level, as long as sufficient thermal contrast exists between the radiative temperatures of the cloud and its surrounding air parcel. Another advantage of the proposed method is its simplicity and modest power needs, making it particularly suitable for field measurements and deployment at remote locations. Our method can be further simplified for use with visible CCD or CMOS camera (although nighttime clouds will not be observed.

Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique.

Science.gov (United States)

Park, Choon-Sang; Kim, Dong Ha; Shin, Bhum Jae; Tae, Heung-Sik

2016-01-11

This work presents a study on the preparation of plasma-polymerized aniline (pPANI) nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ) device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES) techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), and gel permeation chromatography (GPC) techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight ( M w ), about 533 kDa with 1.9 polydispersity index (PDI). This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique.

Synthesis and Characterization of Nanofibrous Polyaniline Thin Film Prepared by Novel Atmospheric Pressure Plasma Polymerization Technique

Directory of Open Access Journals (Sweden)

Choon-Sang Park

2016-01-01

Full Text Available This work presents a study on the preparation of plasma-polymerized aniline (pPANI nanofibers and nanoparticles by an intense plasma cloud type atmospheric pressure plasma jets (iPC-APPJ device with a single bundle of three glass tubes. The nano size polymer was obtained at a sinusoidal wave with a peak value of 8 kV and a frequency of 26 kHz under ambient air. Discharge currents, photo-sensor amplifier, and optical emission spectrometer (OES techniques were used to analyze the plasma produced from the iPC-APPJ device. Field emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, gas chromatography-mass spectrometry (GC-MS, and gel permeation chromatography (GPC techniques were used to analyze the pPANI. FE-SEM and TEM results show that pPANI has nanofibers, nanoparticles morphology, and polycrystalline characteristics. The FT-IR and GC-MS analysis show the characteristic polyaniline peaks with evidence that some quinone and benzene rings are broken by the discharge energy. GPC results show that pPANI has high molecular weight (Mw, about 533 kDa with 1.9 polydispersity index (PDI. This study contributes to a better understanding on the novel growth process and synthesis of uniform polyaniline nanofibers and nanoparticles with high molecular weights using the simple atmospheric pressure plasma polymerization technique.

Structure, optical and electrical properties of indium tin oxide ultra thin films prepared by jet nebulizer spray pyrolysis technique

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M. Thirumoorthi

2016-03-01

Full Text Available Indium tin oxide (ITO thin films have been prepared by jet nebulizer spray pyrolysis technique for different Sn concentrations on glass substrates. X-ray diffraction patterns reveal that all the films are polycrystalline of cubic structure with preferentially oriented along (222 plane. SEM images show that films exhibit uniform surface morphology with well-defined spherical particles. The EDX spectrum confirms the presence of In, Sn and O elements in prepared films. AFM result indicates that the surface roughness of the films is reduced as Sn doping. The optical transmittance of ITO thin films is improved from 77% to 87% in visible region and optical band gap is increased from 3.59 to 4.07 eV. Photoluminescence spectra show mainly three emissions peaks (UV, blue and green and a shift observed in UV emission peak. The presence of functional groups and chemical bonding was analyzed by FTIR. Hall effect measurements show prepared films having n-type conductivity with low resistivity (3.9 × 10−4 Ω-cm and high carrier concentrations (6.1 × 1020 cm−3.

Facile preparation of an alternating copolymer-based high molecular shape-selective organic phase for reversed-phase liquid chromatography.

Science.gov (United States)

Mallik, Abul K; Noguchi, Hiroki; Rahman, Mohammed Mizanur; Takafuji, Makoto; Ihara, Hirotaka

2018-06-22

The synthesis of a new alternating copolymer-grafted silica phase is described for the separation of shape-constrained isomers of polycyclic aromatic hydrocarbons (PAHs) and tocopherols in reversed-phase high-performance liquid chromatography (RP-HPLC). Telomerization of the monomers (octadecyl acrylate and N-methylmaleimide) was carried out with a silane coupling agent; 3-mercaptopropyltrimethoxysilane (MPS), and the telomer (T) was grafted onto porous silica surface to prepare the alternating copolymer-grafted silica phase (Sil-alt-T). The new hybrid material was characterized by elemental analyses, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and solid-state 13 C and 29 Si cross-polarization magic-angle spinning (CP/MAS) NMR spectroscopy. The results of 13 C CP/MAS NMR demonstrated that the alkyl chains of the grafted polymers in Sil-alt-T remained disordered, amorphous, and mobile represented by gauche conformational form. Separation abilities and molecular-shape selectivities of the prepared organic phase were evaluated by the separation of PAHs isomers and Standard Reference Material 869b, Column Selectivity Test Mixture for Liquid Chromatography, respectively and compared with commercially available octadecylsilylated silica (ODS) and C 30 columns as well as previously reported alternating copolymer-based column. The effectiveness of this phase is also demonstrated by the separation of tocopherol isomers. Oriented functional groups along the polymer main chains and cavity formations are investigated to be the driving force for better separation with multiple-interactions with the solutes. One of the advantages of the Sil-alt-T phase to that of the previously reported phase is the synthesis of the telomer first and then immobilized onto silica surface. In this case, the telomer was characterized easily with simple spectroscopic techniques and the molecular mass and polydispersity index of the telomer were determined by size exclusion

Bases of technique of sprinting

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Valeriy Druz

2015-06-01

Full Text Available Purpose: to determine the biomechanical consistent patterns of a movement of a body providing the highest speed of sprinting. Material and Methods: the analysis of scientific and methodical literature on the considered problem, the anthropometrical characteristics of the surveyed contingent of sportsmen, the analysis of high-speed shootings of the leading runners of the world. Results: the biomechanical bases of technique of sprinting make dispersal and movement of the general center of body weight of the sportsman on a parabolic curve in a start phase taking into account the initial height of its stay in a pose of a low start. Its further movement happens on a cycloidal trajectory which is formed due to a pendulum movement of the extremities creating the lifting power which provides flight duration more in a running step, than duration of a basic phase. Conclusions: the received biomechanical regularities of technique of sprinting allow increasing the efficiency of training of sportsmen in sprinting.

Chitosan-based delivery systems for diclofenac delivery: preparation and characterization

Energy Technology Data Exchange (ETDEWEB)

Dreve, Simina; Kacso, Irina; Bratu, Ioan; Indrea, Emil, E-mail: simina.dreve@itim-cj.r [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)

2009-08-01

The preparation and characterization of novel materials for drug delivery has rapidly gained importance in development of innovative medicine. The paper concerns the uses of chitosan as an excipient in oral formulations and as a drug delivery vehicle for burnt painful injuries. The use of chitosan (CTS) as base in polyelectrolyte complex systems, to prepare liquid release systems as hydrogels and solid release systems as sponges is presented. In this paper the preparation of CTS hydrogels and sponges carrying diclofenac (DCF), as anti-inflammatory drug is reported. The immobilization of DCF in CTS is done by mixing the CTS hydrogel with the anti-inflammatory drug solutions. The concentration of anti-inflammatory drug in the CTS hydrogel generating the sponges was of 57 mg/l, 72 mg/l and 114 mg/l. The CTS sponges with anti-inflammatory drugs were prepared by freeze-drying at -610{sup 0}C and 0,09 atm. The characterization of the hydrogels and sponges was done by infrared spectra (FTIR) and ultraviolet-visible spectroscopy (UV-VIS). The results indicated the formation of CTS-DCF intermediates. The DCF molecules are forming temporary chelates in CTS hydrogels and sponges and they are compatible with skin or some of biological fluids with satisfactory results.

Chitosan-based delivery systems for diclofenac delivery: preparation and characterization

International Nuclear Information System (INIS)

Dreve, Simina; Kacso, Irina; Bratu, Ioan; Indrea, Emil

2009-01-01

The preparation and characterization of novel materials for drug delivery has rapidly gained importance in development of innovative medicine. The paper concerns the uses of chitosan as an excipient in oral formulations and as a drug delivery vehicle for burnt painful injuries. The use of chitosan (CTS) as base in polyelectrolyte complex systems, to prepare liquid release systems as hydrogels and solid release systems as sponges is presented. In this paper the preparation of CTS hydrogels and sponges carrying diclofenac (DCF), as anti-inflammatory drug is reported. The immobilization of DCF in CTS is done by mixing the CTS hydrogel with the anti-inflammatory drug solutions. The concentration of anti-inflammatory drug in the CTS hydrogel generating the sponges was of 57 mg/l, 72 mg/l and 114 mg/l. The CTS sponges with anti-inflammatory drugs were prepared by freeze-drying at -610 0 C and 0,09 atm. The characterization of the hydrogels and sponges was done by infrared spectra (FTIR) and ultraviolet-visible spectroscopy (UV-VIS). The results indicated the formation of CTS-DCF intermediates. The DCF molecules are forming temporary chelates in CTS hydrogels and sponges and they are compatible with skin or some of biological fluids with satisfactory results.

Preparation and characterization of sepiolite-based phase change material nanocomposites for thermal energy storage

International Nuclear Information System (INIS)

Konuklu, Yeliz; Ersoy, Orkun

2016-01-01

Highlights: • Sepiolite-based phase change material nanocomposites were prepared. • An easy direct impregnation process was used. • This paper is one of the first study about sepiolite-based phase change material nanocomposites. • Influence of PCM type on thermal properties of nanocomposites was reported. - Abstract: This paper is one of the first study about the preparation and characterization of sepiolite-based phase change material nanocomposites for thermal energy storage applications. Sepiolite is an important natural fibrous raw material. Nanoscale fibrous tubular structure of sepiolite becomes important in nanocomposite preparation. In this study, sepiolite/paraffin and sepiolite/decanoic acid nanocomposites were manufactured by the direct impregnation method. By the preparation of nanocomposites, PCM move in tubular channels of sepiolite, phase changing occurs in these tubes and surface area increases like as in microencapsulation. The structure and properties of nanocomposites PCMs (CPCM) have been characterized via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The SEM results prove the successful preparation of phase change material/sepiolite nanocomposites and point out that the fibers of sepiolite is modified with phase change materials in the nanocomposite. The phase change enthalpies of melting and freezing were about 62.08 J/g and −62.05 J/g for sepiolite/paraffin nanocomposites and 35.69 J/g and −34.55 J/g for sepiolite/decanoic acid nanocomposites, respectively. The results show that PCM/sepiolite nanocomposites were prepared successfully and their properties are very suitable for thermal energy storage applications.

Comparison of the Effect of Canal Preparation by Step Back Technique Using Hand Instruments and Gates Glidden Drills with ProTaper Universal Rotary System on the Root Resistance to Vertical Fracture

OpenAIRE

A Abbaszadegan; Z Sadat Aleyasin; M Sedigh Shamsi; Sh Shahriari

2013-01-01

Introduction: Cleaning and shaping of the root canal system with an efficient and safe technique are the major goals of root canal treatment. The aim of this study was to compare the conventional root canal preparation technique by hand instruments and Gates Glidden drills with ProTaper Universal Rotary system on the root susceptibility to vertical fracture. Methods: Thirty extracted human mandibular premolars were randomly assigned to two groups. In group I, apical preparation was performed ...

Stability of fortified cefazolin ophthalmic solutions prepared in artificial tears containing surfactant-based versus oxidant-based preservatives.

Science.gov (United States)

Rojanarata, Theerasak; Tankul, Junlathip; Woranaipinich, Chayanee; Potawanich, Paweena; Plianwong, Samarwadee; Sakulma, Sirinart; Saehuan, Choedchai

2010-10-01

The aim of this study was to investigate the stability of fortified cefazolin sodium ophthalmic solutions (50 mg mL⁻¹) extemporaneously prepared in commercial artificial tears containing 2 different types of preservatives, namely the surfactants and oxidants. Fortified cefazolin sodium solutions were prepared by reconstituting cefazolin for injection with sterile water and further diluted with Tears Naturale II or Natear, 2 commercial artificial tears containing polyquaternium-1 and sodium perborate, respectively, as preservatives. The solutions were then kept at room temperature (28°C) or in the refrigerator (4°C). During the 28-day period, the formulations were periodically examined for the physical appearance, pH, and the remaining drug concentrations. The antibacterial potency was evaluated as the minimal inhibitory concentration against Staphylococcus aureus strain ATCC 29923 by broth dilution technique. The activity of the preservatives was demonstrated by antimicrobial effectiveness tests. On day 28, the microbial contamination in the preparations was tested. The stability profiles of cefazolin solutions prepared in Tears Naturale II, Natear, and water were not different, but they were significantly influenced by the storage temperature. The refrigerated formulations showed no loss of drug and antibacterial potency as well as alteration of physical appearance and pH throughout the 28 days. In contrast, those kept at room temperature showed gradual change in color and odor. The degradation of drug exceeded 10% from day 3 and the decrease of antibacterial potency could be observed at week 3. All cefazolin solutions prepared in artificial tears retained the antimicrobial activity of preservatives and were free from bacterial and fungal contamination throughout the 28-day period of study. Cefazolin sodium ophthalmic solutions can be extemporaneously prepared in Tears Naturale II or Natear without the influence from different types of preservatives used in

Indirect Fluorescent Antibody Technique based Prevalence of Surra in Equines

Directory of Open Access Journals (Sweden)

Ahsan Nadeem, Asim Aslam*, Zafar Iqbal Chaudhary, Kamran Ashraf1, Khalid Saeed1, Nisar Ahmad1, Ishtiaq Ahmed and Habib ur Rehman2

2011-04-01

Full Text Available This project was carried out to find the prevalence of trypanosomiasis in equine in District Gujranwala by using indirect fluorescent antibody technique and thin smear method. Blood samples were collected from a total of 200 horses and donkeys of different ages and either sex. Duplicate thin blood smears were prepared from each sample and remaining blood samples were centrifuged to separate the serum. Smears from each animal were processed for giemsa staining and indirect fluorescent antibody test (IFAT. Giemsa stained smears revealed Trypanosome infection in 4/200 (2.0% samples and IFAT in 12/200 (6.0% animals.

Preparation and characterization of the PVDF-based composite membrane for direct methanol fuel cells

OpenAIRE

Qian Liu, Laizhou Song, Zhihui Zhang, Xiaowei Liu

2010-01-01

The polyvinylidene fluoride-sulfonated polystyrene composite membrane with proton exchange performance, denoted as PVDF-SPS, was prepared using a thermally induced polymerization technique. The thermal stability of the PVDF-SPS composite membrane was investigated using thermogravimetric (TG) analysis. The complex formation of the composite membrane was ascertained by Fourier transform infrared spectroscopy (FTIR). The surface compositions of the PVDF-SPS membrane were analyzed using X-ray pho...

Irregular distribution of metal ions in ferrites prepared by co-precipitation technique structure analysis of Mn-Zn ferrite using extended X-ray absorption fine structure

International Nuclear Information System (INIS)

Jeyadevan, B.; Tohji, K.; Nakatsuka, K.; Narayanasamy, A.

2000-01-01

The tetrahedral/octahedral site occupancy of non-magnetic zinc ion, added to maximize the net magnetic moment of mixed ferrites has been found to depend on the method of preparation. In this paper, we qualitatively analyze the metal ion distribution in Mn-Zn ferrite particles prepared by co-precipitation and ceramic methods using extended X-ray absorption fine structure (EXAFS) technique. The results suggest that the differences observed in the magnetic properties of the samples prepared by different methods are not only due to the difference in particle size but also due to the difference in cation distribution. The difference in cation distributions between ferrites of similar composition prepared differently has been found to depend on the crystal field stability energies of the metal ion of interest and associated cations

Preparing educators for problem-based and community-based curricula: a student's experiences.

Science.gov (United States)

Dana, N

1997-03-01

The Department of Nursing at the University of Natal Durban (UND) introduced a one year Masters Degree in Progressive Education for Health Professionals in 1996, the aim of which is to prepare educators of health professionals to understand better innovative methods of teaching, learning and more specifically problem-based learning (PBL) and community-based education (CBE). The author of this paper is a registered nurse and this paper focuses on her experiences as a student in this programme. Most of the experiences gained are related to the use of a Personal and Academic Development Portfolio, which covered activities from both her own classes and those related to facilitation of basic student's learning.

Development of Highly Efficient Grafting Technique and Synthesis of Natural Polymer-Based Graft Adsorbent

Energy Technology Data Exchange (ETDEWEB)

Ueki, Y; Seko, N; Tamada, M [Japan Atomic Energy Agency, Quantum Beam Science Directorate, Takasaki (Japan)

2012-09-15

In the framework of the CRP, Japan has focused on the development of fibrous adsorbents for removal of toxic metal ions and recovery of significant metal ions from industrial wastewater and streaming water. Graft polymerization was carried out by using gamma irradiation facility and electron beam accelerator. Emulsion grafting is a novel topic for synthesis of metal ion adsorbents which are prepared from fibrous trunk polymers such as polyethylene fibre and biodegradable nonwoven fabrics. The emulsion grafting, where monomer micelles are dispersed in water in the presence of surfactant, is a highly efficient and economic grafting technique as compared to general organic solvent system. The resultant cotton-based adsorbent has high adsorption efficiency and high adsorption capacity for Hg, besides, it is biodegradable. Polylactic acid can also be used as a trunk material for the grafting. (author)

Preparation and investigation of novel gastro-floating tablets with 3D extrusion-based printing.

Science.gov (United States)

Li, Qijun; Guan, Xiaoying; Cui, Mengsuo; Zhu, Zhihong; Chen, Kai; Wen, Haoyang; Jia, Danyang; Hou, Jian; Xu, Wenting; Yang, Xinggang; Pan, Weisan

2018-01-15

Three dimensional (3D) extrusion-based printing is a paste-based rapid prototyping process, which is capable of building complex 3D structures. The aim of this study was to explore the feasibility of 3D extrusion-based printing as a pharmaceutical manufacture technique for the fabrication of gastro-floating tablets. Novel low-density lattice internal structure gastro-floating tablets of dipyridamole were developed to prolong the gastric residence time in order to improve drug release rate and consequently, improve bioavailability and therapeutic efficacy. Excipients commonly employed in the pharmaceutical study could be efficiently applied in the room temperature 3D extrusion-based printing process. The tablets were designed with three kinds of infill percentage and prepared by hydroxypropyl methylcellulose (HPMC K4M) and hydroxypropyl methylcellulose (HPMC E15) as hydrophilic matrices and microcrystalline cellulose (MCC PH101) as extrusion molding agent. In vitro evaluation of the 3D printed gastro-floating tablets was performed by determining mechanical properties, content uniformity, and weight variation. Furthermore, re-floating ability, floating duration time, and drug release behavior were also evaluated. Dissolution profiles revealed the relationship between infill percentage and drug release behavior. The results of this study revealed the potential of 3D extrusion-based printing to fabricate gastro-floating tablets with more than 8h floating process with traditional pharmaceutical excipients and lattice internal structure design. Copyright © 2017. Published by Elsevier B.V.

Skull base tumours part I: Imaging technique, anatomy and anterior skull base tumours

Energy Technology Data Exchange (ETDEWEB)

Borges, Alexandra [Instituto Portugues de Oncologia Francisco Gentil, Centro de Lisboa, Servico de Radiologia, Rua Professor Lima Basto, 1093 Lisboa Codex (Portugal)], E-mail: borgesalexandra@clix.pt

2008-06-15

Advances in cross-sectional imaging, surgical technique and adjuvant treatment have largely contributed to ameliorate the prognosis, lessen the morbidity and mortality of patients with skull base tumours and to the growing medical investment in the management of these patients. Because clinical assessment of the skull base is limited, cross-sectional imaging became indispensable in the diagnosis, treatment planning and follow-up of patients with suspected skull base pathology and the radiologist is increasingly responsible for the fate of these patients. This review will focus on the advances in imaging technique; contribution to patient's management and on the imaging features of the most common tumours affecting the anterior skull base. Emphasis is given to a systematic approach to skull base pathology based upon an anatomic division taking into account the major tissue constituents in each skull base compartment. The most relevant information that should be conveyed to surgeons and radiation oncologists involved in patient's management will be discussed.

Skull base tumours part I: Imaging technique, anatomy and anterior skull base tumours

International Nuclear Information System (INIS)

Borges, Alexandra

2008-01-01

Advances in cross-sectional imaging, surgical technique and adjuvant treatment have largely contributed to ameliorate the prognosis, lessen the morbidity and mortality of patients with skull base tumours and to the growing medical investment in the management of these patients. Because clinical assessment of the skull base is limited, cross-sectional imaging became indispensable in the diagnosis, treatment planning and follow-up of patients with suspected skull base pathology and the radiologist is increasingly responsible for the fate of these patients. This review will focus on the advances in imaging technique; contribution to patient's management and on the imaging features of the most common tumours affecting the anterior skull base. Emphasis is given to a systematic approach to skull base pathology based upon an anatomic division taking into account the major tissue constituents in each skull base compartment. The most relevant information that should be conveyed to surgeons and radiation oncologists involved in patient's management will be discussed

Proposed satellite position determination systems and techniques for Geostationary Synthetic Aperture Radar

OpenAIRE

Martin Fuster, Roger; Fernández Usón, Marc; Casado Blanco, David; Broquetas Ibars, Antoni

2016-01-01

This paper proposes two different calibration techniques for Geostationary Synthetic Aperture Radar (GEOSAR) missions requiring a high precision positioning, based on Active Radar Calibrators and Ground Based Interferometry. The research is enclosed in the preparation studies of a future GEOSAR mission providing continuous monitoring at continental scale. Peer Reviewed

Preparation and characterization of tin sulphide thin films by a spray pyrolysis technique

International Nuclear Information System (INIS)

Ben Haj Salah, H.; Bouzouita, H.; Rezig, B.

2005-01-01

We have attempted the preparation and characterization of Sn 2 S 3 thin films by using the spray pyrolysis technique. We started with acidic aqueous solutions including tin (II) chloride and thiourea, which were atomized with compressed air as carrier gas. The Sn 2 S 3 thin films were obtained on glass substrates. Thin layers of Sn-S have been grown at various temperatures in the range of 275-325 deg. C and various [S/Sn] ratios. The structural properties have been determined by using X-ray diffraction (XRD). The changes observed in the structural phases during the film formation in dependence of growth temperatures are reported and discussed. The optical constants of the deposited films were obtained using the experimentally recorded transmission and reflectance spectral data as functions of the wavelength, in the range of 300-1800 nm. An analysis of the deduced spectral absorption of the deposited films revealed an optical indirect band gap energy of 1.9-2.2 eV for Sn 2 S 3 layers

Partial discharge characteristics of polymer nanocomposite materials in electrical insulation: a review of sample preparation techniques, analysis methods, potential applications, and future trends.

Science.gov (United States)

Izzati, Wan Akmal; Arief, Yanuar Z; Adzis, Zuraimy; Shafanizam, Mohd

2014-01-01

Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends.

Preparation and characterization of biocomposite film based on chitosan and kombucha tea as active food packaging

DEFF Research Database (Denmark)

Ashrafi, Azam; Jokar, Maryam

2018-01-01

An active film composed of chitosan and kombucha tea (KT) was successfully prepared using the solvent casting technique. The effect of incorporation of KT at the levels 1%–3% w/w on the physical and functional properties of chitosan film was investigated. The antimicrobial activity of chitosan...

Nasal base narrowing of the caucasian nose through the cerclage technique

Directory of Open Access Journals (Sweden)

Mocellin, Marcos

2010-06-01

Full Text Available Introduction: Several techniques can be performed to reduce the nasal base (narrowing, as skin resection vestibular columellar skin resection, resection of skin in elliptical lip narinary, sloughing of skin and advancements (VY technique of Bernstein and the use of cerclage sutures in the nasal base. Objective: To evaluate the technique of cerclage performed in the nasal base, through endonasal rhinoplasty without delivery of basic technique, in the Caucasian nose, reducing the distance inter-alar flare and correcting the wing with consequent improvement in nasal harmony in the whole face. Methods: A retrospective analysis by analysis of clinical documents and photos of 43 patients in whom cerclage was made of the nasal base by resecting skin ellipse in the region of the vestibule and the nasal base (modified technique of Weir using colorless mononylon® 4 "0" with a straight cutting needle. The study was conducted in 2008 and 2009 at Hospital of Paraná Institute of Otolaryngology - IPO in Curitiba, Parana - Brazil. Patients had a follow up ranging 7-12 months. Results: In 100% of cases was achieved an improvement in nasal harmony, by decreasing the inter-alar distance. Conclusion: The encircling with minimal resection of vestibular skin and the nasal base is an effective method for the narrowing of the nasal base in the Caucasian nose, with predictable results and easy to perform.

Preparation of uranium-based oxide catalysts; Preparation de catalyseurs oxydes a base d'uranium

Energy Technology Data Exchange (ETDEWEB)

Bressat, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1965-07-01

We have studied the thermal decomposition of uranyl and uranium IV oxalates as a mean of producing uranium dioxide. We have isolated the main intermediate phases of the decompositions and have indexed the lines of their X-ray diffraction patterns. The oxides produced by the decomposition are ill-defined and unstable: they strongly absorb atmospheric oxygen with modification of the composition and, in certain cases, of the structure (pyrophoric oxide). With a view to obtaining stable oxides, we have prepared mixed uranium-thorium oxalates. In order to prepare an oxalate having a homogeneous composition, it is necessary to adopt a well-defined preparation method: the addition of solutions of thorium and uranium IV nitrates to a continually saturated oxalic acid solution. The mixed oxide obtained from the thermal decomposition of an oxalate U{sub x}Th{sub 1-x}(C{sub 2}O{sub 4}){sub 2}, 2 H{sub 2}O at 500 C for 24 hours in a current of oxygen leads to a cubic structure which is well-defined both in the bulk and superficially when x is less than 0.35. Above this atomic concentration of uranium, some uranium moves out of the lattice in the form of UO{sub 3} or U{sub 3}O{sub 8} according to the temperature. The mixed oxide is not stoichiometric,(U{sub x}Th{sub 1-x}O{sub 2+y}) and the average degree of oxidation of the uranium varies with the temperature and partial oxygen pressure. The oxides thus formed have a high surface area. By dissolving the mixed oxalates in a concentrated solution of ammonium oxalate, it is possible to deposit the catalyst on a support, but the differences in the solubilities of the thorium and uranium IV oxalates in the ammonium oxalate make it impossible to prepare double salts formed either of thorium and uranium and of ammonium. (author) [French] Nous avons etudie la decomposition thermique des oxalates d'uranyle et d'uranium IV en vue d'aboutir au dioxide d'uranium. Nous avons pu isoler les principales phases intermediaires des decompositions

Innovative methods for inorganic sample preparation

Energy Technology Data Exchange (ETDEWEB)

Essling, A.M.; Huff, E.A.; Graczyk, D.G.

1992-04-01

Procedures and guidelines are given for the dissolution of a variety of selected materials using fusion, microwave, and Parr bomb techniques. These materials include germanium glass, corium-concrete mixtures, and zeolites. Emphasis is placed on sample-preparation approaches that produce a single master solution suitable for complete multielement characterization of the sample. In addition, data are presented on the soil microwave digestion method approved by the Environmental Protection Agency (EPA). Advantages and disadvantages of each sample-preparation technique are summarized.

Innovative methods for inorganic sample preparation

International Nuclear Information System (INIS)

Essling, A.M.; Huff, E.A.; Graczyk, D.G.

1992-04-01

Procedures and guidelines are given for the dissolution of a variety of selected materials using fusion, microwave, and Parr bomb techniques. These materials include germanium glass, corium-concrete mixtures, and zeolites. Emphasis is placed on sample-preparation approaches that produce a single master solution suitable for complete multielement characterization of the sample. In addition, data are presented on the soil microwave digestion method approved by the Environmental Protection Agency (EPA). Advantages and disadvantages of each sample-preparation technique are summarized

Composite bonded magnets with controlled anisotropy directions prepared by viscous deformation technique

International Nuclear Information System (INIS)

Yamashita, Fumitoshi; Kawamura, Kiyomi; Okada, Yukihiro; Murakami, Hiroshi; Ogushi, Masaki; Nakano, Masaki; Fukunaga, Hirotoshi

2007-01-01

When a radially anisotropic rare earth bonded magnet for a rotor with a high (BH) max value is magnetized multi-polarly, its flux distributes rectangularly and increases a cogging torque. In order to overcome this difficulty, we newly developed highly dense Sm 2 Fe 17 N 3 and Nd 2 Fe 14 B-based composite bonded magnets with continuously controlled anisotropy directions by using a viscous deformation technique

Preparation and Characterization of Coating Solution Based on Waterborne Polyurethane Dispersion containing Fluorine for Primer on Electro Galvanized Steel Sheet

International Nuclear Information System (INIS)

Jin, Chung Keun; Lim, Sung Hyung

2015-01-01

The purpose of this research was to synthesize fluorine modified waterborne polyurethane dispersion (F-WPU) by soap-free (internal emulsifier) emulsion polymerization techniques, to prepare coating solution based on fluorine modified waterborne polyurethane dispersion (F-WPU) and to compare the chemical and thermo-mechanical properties on the electrogalvanized steel sheet. Environmentally friendly F-WPU was prepared with a fluorinated polyol containing 60 wt% of fluorine. There are various ways of combining a wide variety of fluorinated polyols and diisocyanate to exhibit novel properties of waterborne polyurethane dispersion. Components of coating solution were largely divided into 4 kinds i.e., F-WPU, acrylic emulsion, silane coupling agent, and colloidal silicate. F-WPU coating solution on the electro-galvanized steel sheet showed excellent properties of corrosion resistance, alkali resistance and heat resistance, as compared to other coating solutions using a general waterborne resin. The F-WPU coating solution's reliable effects are possibly due to the fluorine atoms incorporated even in a small amount of F-WPU

Preparation and Characterization of Coating Solution Based on Waterborne Polyurethane Dispersion containing Fluorine for Primer on Electro Galvanized Steel Sheet

Energy Technology Data Exchange (ETDEWEB)

Jin, Chung Keun; Lim, Sung Hyung [Buhmwoo Institute of Technology Research, Hwaseong (Korea, Republic of)

2015-10-15

The purpose of this research was to synthesize fluorine modified waterborne polyurethane dispersion (F-WPU) by soap-free (internal emulsifier) emulsion polymerization techniques, to prepare coating solution based on fluorine modified waterborne polyurethane dispersion (F-WPU) and to compare the chemical and thermo-mechanical properties on the electrogalvanized steel sheet. Environmentally friendly F-WPU was prepared with a fluorinated polyol containing 60 wt% of fluorine. There are various ways of combining a wide variety of fluorinated polyols and diisocyanate to exhibit novel properties of waterborne polyurethane dispersion. Components of coating solution were largely divided into 4 kinds i.e., F-WPU, acrylic emulsion, silane coupling agent, and colloidal silicate. F-WPU coating solution on the electro-galvanized steel sheet showed excellent properties of corrosion resistance, alkali resistance and heat resistance, as compared to other coating solutions using a general waterborne resin. The F-WPU coating solution's reliable effects are possibly due to the fluorine atoms incorporated even in a small amount of F-WPU.

Preparation of Affinity Column Based on Zr4+ Ion for Phosphoproteins Isolation

International Nuclear Information System (INIS)

Lee, Seon Mi; Bae, In Ae; Park, Jung Hyen; Kim, Tae Dong; Choi, Seong Ho

2009-01-01

This paper has described about preparation of Zr 4+ affinity column based on the poly(styreneco- glycidyl methacrylate) prepared by emulsion polymerization of styrene and glycidyl methacrylate in order to isolate phosphopeptide. The Zr 4+ ions were introduced after the phophonation of an epoxy group on polymeric microspheres. The successful preparation of Zr 4+ -immobilized polymeric microsphere stationary phase was confirmed through Fourier transform infrared spectra, optical microscopy, scanning electron microscopy, X-ray photoelectron spectra and inductively coupled plasma-atomic emission spectrometer. The separation efficiency for Zr 4+ affinity column prepared by slurry packing was tested to phosphonated casein and dephosphonated casein. The resolution time (min) of the phosphonated casein was higher than that of dephosphated casein for Zr 4+ affinity polymeric microsphere by liquid chromatography. This Zr 4+ affinity column can be used for isolation of phosphonated casein from casein using liquid chromatography

A correlation-based pulse detection technique for gamma-ray/neutron detectors

International Nuclear Information System (INIS)

Faisal, Muhammad; Schiffer, Randolph T.; Flaska, Marek; Pozzi, Sara A.; Wentzloff, David D.

2011-01-01

We present a correlation-based detection technique that significantly improves the probability of detection for low energy pulses. We propose performing a normalized cross-correlation of the incoming pulse data to a predefined pulse template, and using a threshold correlation value to trigger the detection of a pulse. This technique improves the detector sensitivity by amplifying the signal component of incoming pulse data and rejecting noise. Simulation results for various different templates are presented. Finally, the performance of the correlation-based detection technique is compared to the current state-of-the-art techniques.

Memory Based Machine Intelligence Techniques in VLSI hardware

OpenAIRE

James, Alex Pappachen

2012-01-01

We briefly introduce the memory based approaches to emulate machine intelligence in VLSI hardware, describing the challenges and advantages. Implementation of artificial intelligence techniques in VLSI hardware is a practical and difficult problem. Deep architectures, hierarchical temporal memories and memory networks are some of the contemporary approaches in this area of research. The techniques attempt to emulate low level intelligence tasks and aim at providing scalable solutions to high ...

Preparation and Characterization of a Novel Skin Substitute

OpenAIRE

Carlotta Castagnoli; Mara Fumagalli; Daniela Alotto; Irene Cambieri; Stefania Casarin; Alessia Ostorero; Raffaella Casimiri; Patrizia Germano; Carla Pezzuto; Maurizio Stella

2010-01-01

Autologous epidermal cell cultures (CEA) represent a possibility to treat extensive burn lesions, since they allow a significative surface expansion which cannot be achieved with other surgical techniques based on autologous grafting. Moreover currently available CEA preparations are difficult to handle and their take rate is unpredictable. This study aimed at producing and evaluating a new cutaneous biosubstitute made up of alloplastic acellular glycerolized dermis (AAGD) and CEA to ove...

State of the art of environmentally friendly sample preparation approaches for determination of PBDEs and metabolites in environmental and biological samples: A critical review.

Science.gov (United States)

Berton, Paula; Lana, Nerina B; Ríos, Juan M; García-Reyes, Juan F; Altamirano, Jorgelina C

2016-01-28

Green chemistry principles for developing methodologies have gained attention in analytical chemistry in recent decades. A growing number of analytical techniques have been proposed for determination of organic persistent pollutants in environmental and biological samples. In this light, the current review aims to present state-of-the-art sample preparation approaches based on green analytical principles proposed for the determination of polybrominated diphenyl ethers (PBDEs) and metabolites (OH-PBDEs and MeO-PBDEs) in environmental and biological samples. Approaches to lower the solvent consumption and accelerate the extraction, such as pressurized liquid extraction, microwave-assisted extraction, and ultrasound-assisted extraction, are discussed in this review. Special attention is paid to miniaturized sample preparation methodologies and strategies proposed to reduce organic solvent consumption. Additionally, extraction techniques based on alternative solvents (surfactants, supercritical fluids, or ionic liquids) are also commented in this work, even though these are scarcely used for determination of PBDEs. In addition to liquid-based extraction techniques, solid-based analytical techniques are also addressed. The development of greener, faster and simpler sample preparation approaches has increased in recent years (2003-2013). Among green extraction techniques, those based on the liquid phase predominate over those based on the solid phase (71% vs. 29%, respectively). For solid samples, solvent assisted extraction techniques are preferred for leaching of PBDEs, and liquid phase microextraction techniques are mostly used for liquid samples. Likewise, green characteristics of the instrumental analysis used after the extraction and clean-up steps are briefly discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation and evaluation of some benzimidazole derivatives as antioxidants for local base oil

Directory of Open Access Journals (Sweden)

J.S. Basta

2017-12-01

Full Text Available Some benzimidazole derivatives, 2(1-H benzo(dimidazole-2-y1thio N-butyl acetamide Ia, 2(I-H benzo(dimidazole-2-ylthio N-octylacetamid Ib and 2(I-H benzo(dimidazole-2-yl thio N-dodecylactamide Ic were prepared and studied as antioxidants for base stock. The structure of these compounds was elucidated by elemental analysis, IR and 1H NMR spectroscopy. The inhibition efficiency of the prepared compounds was determined by studying the oxidation stability of the local base oil via the change in total acid number (TAN, viscosity and infrared (IR spectroscopy.

Preparation and Characterization of Some Nanometal Oxides Using Microwave Technique and Their Application to Cotton Fabrics

Directory of Open Access Journals (Sweden)

M. Gouda

2015-01-01

Full Text Available The objective of this paper is the synthesis of some nanometal oxides via microwave irradiation technique and their application to augment multifunctional properties of cotton fabric. Cotton fabrics containing nanometal oxides were prepared via a thiol-modification of cotton fabric samples and then dipped into the metal salt solutions precursors and transferred to the microwave oven. The surface morphology and quantitative analysis of the obtained modified cotton fabrics containing nanometal oxides were studied by scanning electron microscopy coupled with high energy dispersive X-ray (SEM-EDX. The shape and distribution of nanometal oxide inside the fabric samples were analyzed by transmission electron microscopy of cross-section fabric samples. The iron oxide nanoparticles had a nanosphere with particle size diameter 15–20 nm, copper oxide nanoparticles had a nanosphere with particle size diameter 25–30 nm, and cobalt oxide nanoparticles had a nanotube-like shape with a length of 100–150 nanometer and a diameter of ~58 nanometer, whereas the manganese oxide nanoparticles had a linear structure forming nanorods with a diameter of 50–55 nanometer and a length of 70–80 nanometers. Antibacterial activity was evaluated quantitatively against gram-positive bacteria such as Staphylococcus aureus and gram-negative bacteria such as Escherichia coli, UV-protection activity was analyzed using UV-DRS spectroscopy, and flame retardation of prepared fabric samples was evaluated according to the limiting oxygen index (LOI. Results revealed that the prepared fabric sample containing nanometal oxide possesses improved antibacterial, LOI, and UV-absorbing efficiency. Moreover, the metal oxide nanoparticles did not leach out the fabrics by washing even after 30 laundering washing cycles.

Preparation of herpes simplex virus-infected primary neurons for transmission electron microscopy.

Science.gov (United States)

Miranda-Saksena, Monica; Boadle, Ross; Cunningham, Anthony L

2014-01-01

Transmission electron microscopy (TEM) provides the resolution necessary to identify both viruses and subcellular components of cells infected with many types of viruses, including herpes simplex virus. Recognized as a powerful tool in both diagnostic and research-based virology laboratories, TEM has made possible the identification of new viruses and has contributed to the elucidation of virus life cycle and virus-host cell interaction. Whilst there are many sample preparation techniques for TEM, conventional processing using chemical fixation and resin embedding remains a useful technique, available in virtually all EM laboratories, for studying virus/cell ultrastructure. In this chapter, we describe the preparation of herpes simplex virus-infected primary neurons, grown on plastic cover slips, to allow sectioning of neurons and axons in their growth plane. This technique allows TEM examination of cell bodies, axons, growth cones, and varicosities, providing powerful insights into virus-cell interaction.

Properties of Formula 127 glass prepared with radioactive zirconia calcine

International Nuclear Information System (INIS)

Staples, B.A.; Pavlica, D.A.; Cole, H.S.

1982-09-01

Formula 127 glass has been developed to immobilize ICPP zirconia calcine. This glass has been prepared remotely on a laboratory scale basis with actual radioactive zirconia calcine retrieved after ten years of storage from Bin Set 2. The aqueous leachability of the glass produced was investigated and compared through application of the MCC-1, MCC-2 and Soxhlet leach tests with that of Formula 127 glass prepared with simulated calcine. The solid state properties of the glasses prepared with actual and simulated calcines were also measured by electron spectroscopy for chemical analysis (ESCA) and scanning electron microscopy energy dispersive x-ray (SEM-EDX). Based on the application of these leaching tests and analysis techniques the properties measured in this study are similar for 127 glass prepared with either simulated or radioactive calcine. 13 figures, 16 tables

Soil sample preparation using microwave digestion for uranium analysis

International Nuclear Information System (INIS)

Mohagheghi, Amir H.; Preston, Rose; Akbarzadeh, Mansoor; Bakthiar, Steven

2000-01-01

A new sample preparation procedure has been developed for digestion of soil samples for uranium analysis. The technique employs a microwave oven digestion system to digest the sample and to prepare it for separation chemistry and analysis. The method significantly reduces the volume of acids used, eliminates a large fraction of acid vapor emissions, and speeds up the analysis time. The samples are analyzed by four separate techniques: Gamma Spectrometry, Alpha Spectroscopy using the open digestion method, Kinetic Phosphorescence Analysis (KPA) using open digestion, and KPA by Microwave digestion technique. The results for various analytical methods are compared and used to confirm the validity of the new procedure. The details of the preparation technique along with its benefits are discussed

Preparation of W/CuCrZr monoblock test mock-up using vacuum brazing technique

International Nuclear Information System (INIS)

Singh, Kongkham Premjit; Khirwadkar, Samir S.; Bhope, Kedar; Patel, Nikunj; Mokaria, Prakash K.; Mehta, Mayur

2015-01-01

Development of the joining for W/CuCrZr monoblock PFC test mock-up is an interest area in Fusion R and D. W/Cu bimetallic material has prepared using OFHC copper casting approach on the radial surface of W monoblock tile surface. The W/Cu bimetallic material has been joined with CuCrZr tube (heat sink) material with the vacuum brazing route. Vacuum brazing of W/Cu-CuCrZr has been performed @ 970 °C for 10 mins using NiCuMn-37 filler material under deep vacuum environment (10 -6 mbar). Graphite fixtures were used for OFHC copper casting and vacuum brazing experiments. The joint integrity of W/Cu-CuCrZr monoblock mock-up on W/Cu and Cu-CuCrZr has been checked using ultrasonic immersion technique. Micro-structural examination and Spot-wise elemental analysis have been carried out using HR-SEM and EDAX. The results of the experimental work will be discussed in the paper. (author)

Critical evaluation of sample pretreatment techniques.

Science.gov (United States)

Hyötyläinen, Tuulia

2009-06-01

Sample preparation before chromatographic separation is the most time-consuming and error-prone part of the analytical procedure. Therefore, selecting and optimizing an appropriate sample preparation scheme is a key factor in the final success of the analysis, and the judicious choice of an appropriate procedure greatly influences the reliability and accuracy of a given analysis. The main objective of this review is to critically evaluate the applicability, disadvantages, and advantages of various sample preparation techniques. Particular emphasis is placed on extraction techniques suitable for both liquid and solid samples.

A novel computer-aided method to fabricate a custom one-piece glass fiber dowel-and-core based on digitized impression and crown preparation data.

Science.gov (United States)

Chen, Zhiyu; Li, Ya; Deng, Xuliang; Wang, Xinzhi

2014-06-01

Fiber-reinforced composite dowels have been widely used for their superior biomechanical properties; however, their preformed shape cannot fit irregularly shaped root canals. This study aimed to describe a novel computer-aided method to create a custom-made one-piece dowel-and-core based on the digitization of impressions and clinical standard crown preparations. A standard maxillary die stone model containing three prepared teeth each (maxillary lateral incisor, canine, premolar) requiring dowel restorations was made. It was then mounted on an average value articulator with the mandibular stone model to simulate natural occlusion. Impressions for each tooth were obtained using vinylpolysiloxane with a sectional dual-arch tray and digitized with an optical scanner. The dowel-and-core virtual model was created by slicing 3D dowel data from impression digitization with core data selected from a standard crown preparation database of 107 records collected from clinics and digitized. The position of the chosen digital core was manually regulated to coordinate with the adjacent teeth to fulfill the crown restorative requirements. Based on virtual models, one-piece custom dowel-and-cores for three experimental teeth were milled from a glass fiber block with computer-aided manufacturing techniques. Furthermore, two patients were treated to evaluate the practicality of this new method. The one-piece glass fiber dowel-and-core made for experimental teeth fulfilled the clinical requirements for dowel restorations. Moreover, two patients were treated to validate the technique. This novel computer-aided method to create a custom one-piece glass fiber dowel-and-core proved to be practical and efficient. © 2013 by the American College of Prosthodontists.

Characterization techniques for graphene-based materials in catalysis

Directory of Open Access Journals (Sweden)

Maocong Hu

2017-06-01

Full Text Available Graphene-based materials have been studied in a wide range of applications including catalysis due to the outstanding electronic, thermal, and mechanical properties. The unprecedented features of graphene-based catalysts, which are believed to be responsible for their superior performance, have been characterized by many techniques. In this article, we comprehensively summarized the characterization methods covering bulk and surface structure analysis, chemisorption ability determination, and reaction mechanism investigation. We reviewed the advantages/disadvantages of different techniques including Raman spectroscopy, X-ray photoelectron spectroscopy (XPS, Fourier transform infrared spectroscopy (FTIR and Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS, X-Ray diffraction (XRD, X-ray absorption near edge structure (XANES and X-ray absorption fine structure (XAFS, atomic force microscopy (AFM, scanning electron microscopy (SEM, transmission electron microscopy (TEM, high-resolution transmission electron microscopy (HRTEM, ultraviolet-visible spectroscopy (UV-vis, X-ray fluorescence (XRF, inductively coupled plasma mass spectrometry (ICP, thermogravimetric analysis (TGA, Brunauer–Emmett–Teller (BET, and scanning tunneling microscopy (STM. The application of temperature-programmed reduction (TPR, CO chemisorption, and NH3/CO2-temperature-programmed desorption (TPD was also briefly introduced. Finally, we discussed the challenges and provided possible suggestions on choosing characterization techniques. This review provides key information to catalysis community to adopt suitable characterization techniques for their research.

Laser ablation inductively coupled plasma mass spectrometry analysis of agricultural soils using the sol-gel technique of pellet preparation

International Nuclear Information System (INIS)

Hubova, I.; Hola, M.; Vaculovic, T.; Pinkas, J.; Prokes, L.; Stefan, I.; Kanicky, V.

2009-01-01

Full text: Monitoring of metals in agricultural soils is gaining importance as they are accumulated by plants. A LAICPQMS method with Nd:YAG 213 nm laser has been developed for determination of Cr, Ni, Cu, Zn and Pb in soil pellets prepared by the sol-gel technique. LA-ICPMS analysis of archive samples was verified by XRF of wax-soil pellets and ICPMS with nebulization of solutions obtained by total soil decomposition and by analysis of reference materials. Sequention extraction was used for fractionation analysis. (author)

Preparation of high crystalline nanoparticles of rare-earth based complex pervoskites and comparison of their structural and magnetic properties with bulk counterparts

DEFF Research Database (Denmark)

Basith, M. A.; Islam, M. A.; Ahmmad, Bashir

2017-01-01

of crystalline and amorphous phases. FESEM images demonstrate the formation of nanoparticles with average particle size in the range of 50–100 nm for both ultrasonication and 4 h (h) of ball milling. The bulk materials and nanoparticles synthesized by both ultrasonication and 4 h ball milling exhibit...... of the nanoparticles due to ball milling particularly for milling time exceeding 8 h. This investigation demonstrates the potential of ultrasonication as a simple route to prepare high crystalline rare-earth based manganite nanoparticles with improved control compared to the traditional ball milling technique....

Tetraphenylpyrimidine-Based AIEgens: Facile Preparation, Theoretical Investigation and Practical Application

Directory of Open Access Journals (Sweden)

Junkai Liu

2017-10-01

Full Text Available Aggregation-induced emission (AIE has become a hot research area and tremendous amounts of AIE-active luminogens (AIEgens have been generated. To further promote the development of AIE, new AIEgens are highly desirable. Herein, new AIEgens based on tetraphenylpyrimidine (TPPM are rationally designed according to the AIE mechanism of restriction of intramolecular motion, and facilely prepared under mild reaction conditions. The photophysical property of the generated TPPM, TPPM-4M and TPPM-4P are systematically investigated and the results show that they feature the aggregation-enhanced emission (AEE characteristics. Theoretical study shows the high-frequency bending vibrations in the central pyrimidine ring of TPPM derivatives dominate the nonradiative decay channels. Thanks to the AEE feature, their aggregates can be used to detect explosives with super-amplification quenching effects, and the sensing ability is higher than typical AIE-active tetraphenylethene. It is anticipated that TPPM derivatives could serve as a new type of widely used AIEgen based on their facile preparation and good thermo-, photo- and chemostabilities.

Synthesis and studies of Y-Ba-Cu-O high temperature superconductor prepared by sol-gel method

International Nuclear Information System (INIS)

Grigoryan, S.G.; Manukyan, A.L.; Hayrapetyan, A.G.; Arzumanyan, A.M.; Rashidyan, L.H.; Mkrtichyan, N.Y.; Mkrtchyan, A.A.; Kurginyan, K.A.; Trozyan, A.H.; Vardanyan, R.S.

2004-01-01

The method of preparation of Y-Ba-Cu-O high temperature superconducting materials by sol-gel processing technique both for powders and thin films are described. All these methods are based on using yttrium alkoxides as precursors, which are not ready available reagents, besides the majority of these methods use copper alkoxides, which show low solubility in organic solvents, moreover they are very sensitive to hydrolysis in air. The new method of preparation of Y-Ba-Cu-O ceramic materials by sol-gel processing technique based on new and convenient precursors stable in air, having high compatibility with each other is offered. Basic scientific and technological issues related to the synthesis of bulk materials, their structure and electrical conductivity are discussed

Spherical nanostructured Si/C composite prepared by spray drying technique for lithium ion batteries anode

Energy Technology Data Exchange (ETDEWEB)

Chen Libao [Energy Science and Technology Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Xie Xiaohua [Energy Science and Technology Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Wang Baofeng [Department of Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang Ke [Energy Science and Technology Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Xie Jingying [Energy Science and Technology Laboratory, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China) and Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)]. E-mail: jyxie@mail.sim.ac.cn

2006-07-15

Spherical nanostructured Si/C composite was prepared by spray drying technique, followed by heat treatment, in which nanosized silicon and fine graphite particles were homogeneously embedded in carbon matrix pyrolyzed by phenol formaldehyde resin. Cyclic voltammetry tests showed two pairs of redox peaks corresponding to lithiation and delithiation of Si/C composite. The Si/C composite exhibited a reversible capacity of 635 mAh g{sup -1} and good cycle performance used in lithium ion batteries. To improve cycle performance of this Si/C composite further, the carbon-coated Si/C composite was synthesized by the second spray drying and heat treatment processing. The cycle performance of carbon-coated Si/C composite was improved significantly, which was attributed to the formation of stable SEI passivation layers on the outer surface of carbon shell which protected the bared silicon from exposing to electrolyte directly.

Spherical nanostructured Si/C composite prepared by spray drying technique for lithium ion batteries anode

International Nuclear Information System (INIS)

Chen Libao; Xie Xiaohua; Wang Baofeng; Wang Ke; Xie Jingying

2006-01-01

Spherical nanostructured Si/C composite was prepared by spray drying technique, followed by heat treatment, in which nanosized silicon and fine graphite particles were homogeneously embedded in carbon matrix pyrolyzed by phenol formaldehyde resin. Cyclic voltammetry tests showed two pairs of redox peaks corresponding to lithiation and delithiation of Si/C composite. The Si/C composite exhibited a reversible capacity of 635 mAh g -1 and good cycle performance used in lithium ion batteries. To improve cycle performance of this Si/C composite further, the carbon-coated Si/C composite was synthesized by the second spray drying and heat treatment processing. The cycle performance of carbon-coated Si/C composite was improved significantly, which was attributed to the formation of stable SEI passivation layers on the outer surface of carbon shell which protected the bared silicon from exposing to electrolyte directly

The PZC-based Tc-99m generator preparation and its performance test

International Nuclear Information System (INIS)

Liu Yishu

2007-01-01

This paper described the preparation of Tc-99m generator prepared with Japan distributing Mo adsorbent PZC and irradiated nature MoO 3 and its performance test. Four Tc-99m generators were prepared with different batches of PZC and reactor irradiated nature MoO 3 . The adsorption capacity of PZC to Mo is approximately 200mgMo/gPZC. The adsorption efficiency of three batches PZC is good (>90%) and that of one batch of PZC is not good enough (∼83%). The loss of fine powder (The PZC is fragile) is quite different with the different preparation process of PZC. The elution efficiency is 80-90% and has the up trend with the elution date. The Mo breakthrough can be controlled to acceptable level by connecting HZO safe column containing 1.0g HZO. All the specifications of eluted from PZC-based Tc-99m generator can meet the requirements under Sodium Pertechnetate injection in China Pharmacopoeia. (author)

Application of X-ray fluorescence analytical techniques in phytoremediation and plant biology studies

International Nuclear Information System (INIS)

Necemer, Marijan; Kump, Peter; Scancar, Janez; Jacimovic, Radojko; Simcic, Jurij; Pelicon, Primoz; Budnar, Milos; Jeran, Zvonka; Pongrac, Paula; Regvar, Marjana; Vogel-Mikus, Katarina

2008-01-01

Phytoremediation is an emerging technology that employs the use of higher plants for the clean-up of contaminated environments. Progress in the field is however handicapped by limited knowledge of the biological processes involved in plant metal uptake, translocation, tolerance and plant-microbe-soil interactions; therefore a better understanding of the basic biological mechanisms involved in plant/microbe/soil/contaminant interactions would allow further optimization of phytoremediation technologies. In view of the needs of global environmental protection, it is important that in phytoremediation and plant biology studies the analytical procedures for elemental determination in plant tissues and soil should be fast and cheap, with simple sample preparation, and of adequate accuracy and reproducibility. The aim of this study was therefore to present the main characteristics, sample preparation protocols and applications of X-ray fluorescence-based analytical techniques (energy dispersive X-ray fluorescence spectrometry-EDXRF, total reflection X-ray fluorescence spectrometry-TXRF and micro-proton induced X-ray emission-micro-PIXE). Element concentrations in plant leaves from metal polluted and non-polluted sites, as well as standard reference materials, were analyzed by the mentioned techniques, and additionally by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). The results were compared and critically evaluated in order to assess the performance and capability of X-ray fluorescence-based techniques in phytoremediation and plant biology studies. It is the EDXRF, which is recommended as suitable to be used in the analyses of a large number of samples, because it is multi-elemental, requires only simple preparation of sample material, and it is analytically comparable to the most frequently used instrumental chemical techniques. The TXRF is compatible to FAAS in sample preparation, but relative to AAS it is fast, sensitive and

Recent advances in column switching sample preparation in bioanalysis.

Science.gov (United States)

Kataoka, Hiroyuki; Saito, Keita

2012-04-01

Column switching techniques, using two or more stationary phase columns, are useful for trace enrichment and online automated sample preparation. Target fractions from the first column are transferred online to a second column with different properties for further separation. Column switching techniques can be used to determine the analytes in a complex matrix by direct sample injection or by simple sample treatment. Online column switching sample preparation is usually performed in combination with HPLC or capillary electrophoresis. SPE or turbulent flow chromatography using a cartridge column and in-tube solid-phase microextraction using a capillary column have been developed for convenient column switching sample preparation. Furthermore, various micro-/nano-sample preparation devices using new polymer-coating materials have been developed to improve extraction efficiency. This review describes current developments and future trends in novel column switching sample preparation in bioanalysis, focusing on innovative column switching techniques using new extraction devices and materials.

Trends in sample preparation 2002. Development and application. Book of abstracts

International Nuclear Information System (INIS)

Wenzl, T.; Eberl, M.; Zischka, M.; Knapp, G.

2002-01-01

This conference comprised topics dealing with sample preparation such as: sample decomposition, solvent extraction, derivatization techniques and uncertainty in sample preparation. In particular microwave assisted sample preparation techniques and equipment were discussed. The papers were organized under the general topics: trace element analysis, trace analysis of organic compounds, high performance instrumentation in sample preparation, speciation analysis and posters session. Those papers of INIS interest are cited individually. (nevyjel)

Trends in sample preparation 2002. Development and application. Book of abstracts

Energy Technology Data Exchange (ETDEWEB)

Wenzl, T; Eberl, M; Zischka, M; Knapp, G [eds.

2002-07-01

This conference comprised topics dealing with sample preparation such as: sample decomposition, solvent extraction, derivatization techniques and uncertainty in sample preparation. In particular microwave assisted sample preparation techniques and equipment were discussed. The papers were organized under the general topics: trace element analysis, trace analysis of organic compounds, high performance instrumentation in sample preparation, speciation analysis and posters session. Those papers of INIS interest are cited individually. (nevyjel)

Preparation of new composite ceramics based on gadolinium-doped ceria and magnesia nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Yao, Jingying; Schelter, Matthias; Zosel, Jens; Oelssner, Wolfram [Kurt-Schwabe-Institut fuer Mess- und Sensortechnik e.V. Meinsberg, Waldheim (Germany); Mertig, Michael [Kurt-Schwabe-Institut fuer Mess- und Sensortechnik e.V. Meinsberg, Waldheim (Germany); Physikalische Chemie, Mess- und Sensortechnik, Technische Universitaet Dresden (Germany)

2017-09-15

To achieve solid electrolyte materials for electrochemical energy storage devices with very high oxygen ion conductivity, composites of gadolinium-doped ceria (GDC) and magnesia (MgO) are developed in this study. Three different preparation methods are used to prepare nanoparticles from these two components. According to the characterization results, the self-propagating high-temperature synthesis is best suited for the preparation of both nanometer-sized GDC powder as solid electrolyte and MgO powder as insulator. The structures of the prepared nanometer-sized powders have been characterized by X-ray diffraction and transmission electron microscopy. They show narrow size distributions in the lower nanometer range. Then, dense composite ceramics are prepared from a MgO-GDC mixture by sintering. The size of the crystallite domains in the sintered ceramic is in the upper nanometer range. TEM and TEM-EDX images of a new composite ceramic based on gadolinium-doped ceria and magnesia nanoparticles. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Preparation of new composite ceramics based on gadolinium-doped ceria and magnesia nanoparticles

International Nuclear Information System (INIS)

Yao, Jingying; Schelter, Matthias; Zosel, Jens; Oelssner, Wolfram; Mertig, Michael

2017-01-01

To achieve solid electrolyte materials for electrochemical energy storage devices with very high oxygen ion conductivity, composites of gadolinium-doped ceria (GDC) and magnesia (MgO) are developed in this study. Three different preparation methods are used to prepare nanoparticles from these two components. According to the characterization results, the self-propagating high-temperature synthesis is best suited for the preparation of both nanometer-sized GDC powder as solid electrolyte and MgO powder as insulator. The structures of the prepared nanometer-sized powders have been characterized by X-ray diffraction and transmission electron microscopy. They show narrow size distributions in the lower nanometer range. Then, dense composite ceramics are prepared from a MgO-GDC mixture by sintering. The size of the crystallite domains in the sintered ceramic is in the upper nanometer range. TEM and TEM-EDX images of a new composite ceramic based on gadolinium-doped ceria and magnesia nanoparticles. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The nightmare of indeterminate follicular proliferations: when liquid-based cytology and ancillary techniques are not a moon landing but a realistic plan.

Science.gov (United States)

Rossi, Esther Diana; Fadda, Guido; Schmitt, Fernando

2014-01-01

Thyroid nodules are a common finding in the general population, including both nonneoplastic and neoplastic entities. Fine-needle aspiration cytology (FNAC) is the first tool for evaluating thyroid nodules. In spite of its high diagnostic accuracy, 25% of nodules result in the category of follicular neoplasms (FN), with varying risk of malignancy and different management strategies. The use of ancillary techniques is reshaping the practice of FNAC. These tools can significantly empower the morphological diagnosis and prognosis of thyroid nodules, allowing a more accurate prediction of the nature of the lesion. Several studies have underlined the role of single or multiple testing for the category of FN as strong indicators of cancer. Every cytological preparation can be used for the application of ancillary techniques but the introduction of liquid-based cytology (LBC) might facilitate the application. Our experience involving an immunocytochemical panel made up of HBME-1 and galectin-3 pointed to an 81% overall diagnostic accuracy in discriminating between low and high risk of malignancy in FN. The application of these techniques on LBC represents an adjunct to the morphological evaluation of FN. They represent a critical and challenging, but also a feasible, tool in the preoperative diagnoses, allowing specific prognostic and predictive details regardless of the cytological preparation. © 2014 S. Karger AG, Basel.

Changes in implant stability using different site preparation techniques: twist drills versus piezosurgery. A single-blinded, randomized, controlled clinical trial.

Science.gov (United States)

Stacchi, Claudio; Vercellotti, Tomaso; Torelli, Lucio; Furlan, Fabio; Di Lenarda, Roberto

2013-04-01

The objective of the present investigation was to longitudinally monitor stability changes of implants inserted using traditional rotary instruments or piezoelectric inserts, and to follow their variations during the first 90 days of healing. A randomized, controlled trial was conducted on 20 patients. Each patient received two identical, adjacent implants in the upper premolar area: the test site was prepared with piezosurgery, and the control site was prepared using twist drills. Resonance frequency analysis measurements were taken by a blinded operator on the day of surgery and after 7, 14, 21, 28, 42, 56, and 90 days. At 90 days, 39 out of 40 implants were osseointegrated (one failure in the control group). Both groups showed an initial decrease in mean implant stability quotient (ISQ) values: a shift in implant stability to increasing ISQ values occurred after 14 days in the test group and after 21 days in the control group. The lowest mean ISQ value was recorded at 14 days for test implants (97.3% of the primary stability) and at 21 days for the control implants (90.8% of the primary stability). ISQ variations with respect to primary stability differed significantly between the two groups during the entire period of observation: from day 14 to day 42, in particular, the differences were extremely significant (p < .0001). All 39 implants were in function successfully at the visit scheduled 1 year after insertion. The findings from this study suggest that ultrasonic implant site preparation results in a limited decrease of ISQ values and in an earlier shifting from a decreasing to an increasing stability pattern, when compared with the traditional drilling technique. From a clinical point of view, implants inserted with the piezoelectric technique demonstrated a short-term clinical success similar to those inserted using twist drills. © 2011 Wiley Periodicals, Inc.

Synthesis and preparation of biocompatible and pH-responsive cyclodextrin-based nanoparticle

International Nuclear Information System (INIS)

Hu, Xiaohong; Chen, Shangneng; Gong, Xiao; Gao, Ziyu; Wang, Xin; Chen, Pin

2017-01-01

As a temporarily protective reaction for active hydrogen group, acetylation is reversible and responsive to low pH value. According to the reaction, pH-sensitive β-cyclodextrin (β-CD) was synthesized in the first step of our research. During the synthesis, the acetal groups including linear acetal (LA) groups and cyclic acetal (CA) groups were successfully modified onto β-CD. Particularly, the structural details of acetalated β-CD (Ac-β-CD) were greatly influenced by reaction time. Furthermore, in respect to water solubility, Ac-β-CDs exhibited different pH response properties due to their different structure. In the second step, Ac-β-CD1 nanoparticles were prepared by a single oil-in-water (O/W) emulsion technique using a biocompatible emulsifier, gelatin. Meanwhile, gelatin was absorbed onto the surface of nanoparticle, which was confirmed by FTIR spectra. The formed nanoparticles showed monodispersion and nearly spherical morphology. In order to obtain optimal preparing conditions, the effects of preparative parameters such as gelatin concentration, Ac-β-CD concentration, and water/oil ratio on properties including diameters and zeta potential as well as gelatin content were investigated. Moreover, the pH response properties of nanoparticle were characterized by transparency of nanoparticle solution. Finally, in vitro cell culture confirmed that Ac-β-CD nanoparticle could support cell survival and enhance cell viability.

Synthesis and preparation of biocompatible and pH-responsive cyclodextrin-based nanoparticle

Energy Technology Data Exchange (ETDEWEB)

Hu, Xiaohong, E-mail: huxiaohong07@163.com; Chen, Shangneng [Jinling Institute of Technology, School of Material Engineering (China); Gong, Xiao [Wuhan University of Technology, State Key Laboratory of Silicate Materials for Architectures (China); Gao, Ziyu; Wang, Xin; Chen, Pin [Jinling Institute of Technology, School of Material Engineering (China)

2017-03-15

As a temporarily protective reaction for active hydrogen group, acetylation is reversible and responsive to low pH value. According to the reaction, pH-sensitive β-cyclodextrin (β-CD) was synthesized in the first step of our research. During the synthesis, the acetal groups including linear acetal (LA) groups and cyclic acetal (CA) groups were successfully modified onto β-CD. Particularly, the structural details of acetalated β-CD (Ac-β-CD) were greatly influenced by reaction time. Furthermore, in respect to water solubility, Ac-β-CDs exhibited different pH response properties due to their different structure. In the second step, Ac-β-CD1 nanoparticles were prepared by a single oil-in-water (O/W) emulsion technique using a biocompatible emulsifier, gelatin. Meanwhile, gelatin was absorbed onto the surface of nanoparticle, which was confirmed by FTIR spectra. The formed nanoparticles showed monodispersion and nearly spherical morphology. In order to obtain optimal preparing conditions, the effects of preparative parameters such as gelatin concentration, Ac-β-CD concentration, and water/oil ratio on properties including diameters and zeta potential as well as gelatin content were investigated. Moreover, the pH response properties of nanoparticle were characterized by transparency of nanoparticle solution. Finally, in vitro cell culture confirmed that Ac-β-CD nanoparticle could support cell survival and enhance cell viability.

Development of Energy Management System Based on Internet of Things Technique

OpenAIRE

Wen-Jye Shyr; Chia-Ming Lin and Hung-Yun Feng

2017-01-01

The purpose of this study was to develop an energy management system for university campuses based on the Internet of Things (IoT) technique. The proposed IoT technique based on WebAccess is used via network browser Internet Explore and applies TCP/IP protocol. The case study of IoT for lighting energy usage management system was proposed. Structure of proposed IoT technique included perception layer, equipment layer, control layer, application layer and network layer.

Adaptation and micro-structure of Co-Cr alloy maxillary complete denture base plates fabricated by selective laser melting technique.

Science.gov (United States)

Ye, Ye; Jiao, Ting; Zhu, Jiarui; Sun, Jian

2018-01-24

The purpose of the study was to evaluate the adaptation and micro-structure of Co-Cr alloy maxillary complete denture base plates fabricated by the selective laser melting (SLM) technique. Twenty pairs of edentulous casts were randomly and evenly divided into two groups, and manufacturing of the Co-Cr alloy maxillary complete denture base was conducted either by the SLM technique or by the conventional method. The base-cast sets were transversally sectioned into three sections at the distal canines, mesial of the first molars and the posterior palatal zone. The gap between the metal base and cast was measured in these three sections with a stereoscopic microscope, and the data were analysed using t tests. A total of five specimens of 5 mm diameter were fabricated with the Co-Cr alloy by SLM and the traditional casting technology. A scanning electron microscope (SEM) was used to evaluate the differences in microstructure between these specimens. There was no statistical difference between the three sections in all four groups (P > 0.05). At the region of the canines, the clearance value for the SLM Co-Cr alloy group was larger than that of the conventional method group (P  0.05). The SLM Co-Cr alloy has a denser microstructure behaviour and less casting defect than the cast Co-Cr alloy. The SLM technique showed initial feasibility for the manufacture of dental bases of complete dentures, but large sample studies are needed to prove its reliability in clinical applications. The mechanical properties and microstructure of the denture frameworks prepared by selective laser melting indicate that these dentures are appropriate for clinical use.

The Development of an In-Situ TEM Technique for Studying Corrosion Behavior as Applied to Zirconium-Based Alloys

Science.gov (United States)

Harlow, Wayne

Zirconium-based alloys are a commonly used material for nuclear fuel rod cladding, due to its low neutron cross section and good corrosion properties. However, corrosion is still a limiting factor in fuel rod lifespan, which restricts burn up levels, and thus efficiency, that can be achieved. While long-term corrosion behavior has been studied through both reactor and autoclave samples, the oxide nucleation and growth behavior has not been extensively studied. This work develops a new technique to study the initial stages of corrosion in zirconium-based alloys and the microstructural effects on this process by developing an environmental cell system for the TEM. Nanoscale oxidation parameters are developed, as is a new FIB technique to support this method. Precession diffraction is used in conjunction with in-situ TEM to observe the initial stages of corrosion in these alloys, and oxide thickness is estimated using low-loss EELS. In addition, the stress stabilization of tetragonal ZrO 2 is explored in the context of sample preparation for TEM. It was found that in-situ environmental TEM using an environmental cell replicates the oxidation behavior observed in autoclaved samples in both oxide structure and phases. Utilizing this technique, it was shown that cracking of the oxide layer in zirconium-based alloys is related to oxide relaxation, and not thermal changes. The effect of secondary phase particles on oxidation behavior did not present significant results, however a new method for studying initial oxidation rates using low-loss EELS was developed.

Efficient acetone sensor based on Ni-doped ZnO nanostructures prepared by spray pyrolysis technique

Science.gov (United States)

Darunkar, Swapnil S.; Acharya, Smita A.

2018-05-01

Ni-doped ZnO thin film was prepared by home-built spray pyrolysis unit for the detection of acetone at 300°C. Scanning electron microscopic (SEM) images of as-developed thin film of undoped ZnO exhibits large quantity of spherical, non-agglomerated particles with uniform size while in Ni-doped ZnO, particles are quite non-uniform in nature. The particle size estimated by using image J are obtained to be around 20-200 nm. Ni-doping effect on band gaps are determined by UV-vis optical spectroscopy and band gap of Ni-doped ZnO is found to be 3.046 eV. Nickel doping exceptionally enhances the sensing response of ZnO as compared to undoped ZnO system. The major role of the Ni-doping is to create more active sites for chemisorbed oxygen on the surface of sensor and correspondingly, to improve the sensing response. The 6 at.% of Ni-doped ZnO exhibits the highest response (92%) for 100 ppm acetone at 300 °C.

Source preparation in alpha spectrometry

Energy Technology Data Exchange (ETDEWEB)

Lally, A E [UKAEA Atomic Energy Research Establishment, Harwell. Environmental and Medical Sciences Div.; Glover, K M [UKAEA Atomic Energy Research Establishment, Harwell. Chemistry Div.

1984-06-15

Techniques, for the preparation of sources suitable for alpha spectrometric measurements are presented. These include vacuum sublimation, electrodeposition, self-deposition, direct evaporation, direct precipitation and the use of solvents and spreading agents. The relative merits of each technique and the applicability to both high and low levels of activity are considered.

A Web-based approach to blood donor preparation.

Science.gov (United States)

France, Christopher R; France, Janis L; Kowalsky, Jennifer M; Copley, Diane M; Lewis, Kristin N; Ellis, Gary D; McGlone, Sarah T; Sinclair, Kadian S

2013-02-01

Written and video approaches to donor education have been shown to enhance donation attitudes and intentions to give blood, particularly when the information provides specific coping suggestions for donation-related concerns. This study extends this work by comparing Web-based approaches to donor preparation among donors and nondonors. Young adults (62% female; mean [±SD] age, 19.3 [±1.5] years; mean [range] number of prior blood donations, 1.1 [0-26]; 60% nondonors) were randomly assigned to view 1) a study Web site designed to address common blood donor concerns and suggest specific coping strategies (n = 238), 2) a standard blood center Web site (n = 233), or 3) a control Web site where participants viewed videos of their choice (n = 202). Measures of donation attitude, anxiety, confidence, intention, anticipated regret, and moral norm were completed before and after the intervention. Among nondonors, the study Web site produced greater changes in donation attitude, confidence, intention, and anticipated regret relative to both the standard and the control Web sites, but only differed significantly from the control Web site for moral norm and anxiety. Among donors, the study Web site produced greater changes in donation confidence and anticipated regret relative to both the standard and the control Web sites, but only differed significantly from the control Web site for donation attitude, anxiety, intention, and moral norm. Web-based donor preparation materials may provide a cost-effective way to enhance donation intentions and encourage donation behavior. © 2012 American Association of Blood Banks.

The development of latent fingerprints by zinc oxide and tin oxide nanoparticles prepared by precipitation technique

Science.gov (United States)

Luthra, Deepali; Kumar, Sacheen

2018-05-01

Fingerprints are the very important evidence at the crime scene which must be developed clearly with shortest duration of time to solve the case. Metal oxide nanoparticles could be the mean to develop the latent fingerprints. Zinc oxide and Tin Oxide Nanoparticles were prepared by using chemical precipitation technique which were dried and characterized by X-ray diffraction, UV-Visible spectroscopy and FTIR. The size of zinc oxide crystallite was found to be 14.75 nm with minimum reflectance at 360 nm whereas tin oxide have the size of 90 nm and reflectance at minimum level 321 nm. By using these powdered samples on glass, plastic and glossy cardboard, latent fingerprints were developed. Zinc oxide was found to be better candidate than tin oxide for the fingerprint development on all the three types of substrates.

Optical and structural properties of ZnO/ZnMgO composite thin films prepared by sol–gel technique

International Nuclear Information System (INIS)

Xu, Linhua; Su, Jing; Chen, Yulin; Zheng, Gaige; Pei, Shixin; Sun, Tingting; Wang, Junfeng; Lai, Min

2013-01-01

Highlights: ► ZnMgO thin film and ZnO/ZnMgO composite thin film have been prepared by sol–gel method. ► The intensity of ultraviolet emission of ZnMgO thin film is enhanced two times compared with that of pure ZnO thin film. ► Compared with ZnMgO thin film, ZnO/ZnMgO composite thin film shows better crystallization and optical properties. ► ZnO/ZnMgO composite thin films prepared by sol–gel method have potential applications in many optoelectronic devices. - Abstract: In this study, pure ZnO thin film, Mg-doped ZnO (ZnMgO) thin film, ZnO/ZnMgO and ZnMgO/ZnO composite thin films were prepared by sol–gel technique. The structural and optical properties of the samples were analyzed by X-ray diffraction, scanning electron microscopy, UV–visible spectrophotometer, ellipsometer and photoluminescence spectra, respectively. The results showed that the incorporation of Mg increased the strain, broadened the optical bandgap, and improved the intensity of ultraviolet emission of ZnO thin film. The full width at half maximum (FWHM) of the ultraviolet emission peak was also increased due to Mg-doping at the same time. Compared with pure ZnO and ZnMgO thin films, the ZnO/ZnMgO thin film showed better crystalline quality and ultraviolet emission performance, smaller strains and higher transmittance in the visible range.

Succinate-based preparation alleviates manifestations of the climacteric syndrome in women.

Science.gov (United States)

Peskov, A B; Maevskii, E I; Uchitel', M L; Sakharova, N Yu; Vize-Khripunova, M A

2005-09-01

Clinical placebo-controlled study of Enerlit-Clima (bioactive succinate-based food additive) a showed positive effect of the preparation on general clinical and psychoemotional manifestations of the climacteric syndrome. A trend to an increase in estradiol level in early pathological climacteric and normalization of the endometrial status were observed.

Techniques for CAD reconstruction of 'as-built' environments and application to preparing for dismantling of plants

International Nuclear Information System (INIS)

Pot, J.; Levesque, P.

1997-01-01

Electricite de France is using CAD-generated numeric geometrical models to simulate maintenance operations and enable optimizing maintenance procedures. These models are also used to program the machines or robots for certain servicing procedures. They are used in the operator interfaces for robot control, and provide the operator with virtual cameras or enable generating specific information (such as virtual force feedback). Even more recently, CAD models have been integrated in what is known as 'virtual reality' software, giving the operators a sensation of 'immersion' in a virtual universe. Depending on the need and on the type of results expected from the simulations, one needs more or less precise models of the environment in which work will be performed. EDF is using several techniques to get 'as-built' models of the environments. This article describes the SOISIC system, which is a 3D laser sensor widely used for environment data acquisition, associated with 3Dipsos software, for CAD model reconstruction. These techniques, and the applications subsequently developed formaintenance applications, can be used in preparing and carrying out dismantling operations: 'as-built' CAD modeling of the installation can be used in the preparatory phase, providing plans, simulating the varioussteps, calculating waste volumes, helping in optimization of waste management, etc. These models can also be used during the actual dismantling process, to program the machines or robots used, or in the robot or machinesupervisory system. Some of the presented techniques have been used in a room in the Brennilis plant, which is currently being dismantled. (orig.)

The failures of root canal preparation with hand ProTaper.

Science.gov (United States)

Bătăiosu, Marilena; Diaconu, Oana; Moraru, Iren; Dăguci, C; Tuculină, Mihaela; Dăguci, Luminiţa; Gheorghiţă, Lelia

2012-07-01

The failures of root canal preparation are due to some anatomical deviation (canal in "C" or "S") and some technique errors. The technique errors are usually present in canal root cleansing and shaping stage and are the result of endodontic treatment objectives deviation. Our study was made on technique errors while preparing the canal roots with hand ProTaper. Our study was made "in vitro" on 84 extracted teeth (molars, premolars, incisors and canines). The canal root of these teeth were cleansed and shaped with hand ProTaper by crown-down technique and canal irrigation with NaOCl(2,5%). The dental preparation control was made by X-ray. During canal root preparation some failures were observed like: canal root overinstrumentation, zipping and stripping phenomenon, discarded and/or fractured instruments. Hand ProTaper represents a revolutionary progress of endodontic treatment, but a deviation from accepted rules of canal root instrumentation can lead to failures of endodontic treatment.

Effect of thermal spray processing techniques on the microstructure and properties of Ni-based amorphous coatings

International Nuclear Information System (INIS)

Lee, S.M.; Moon, B.M.; Fleury, E.; Ahn, H.S.; Kim, D.H.; Kim, W.T.; Sordelet, D.J.

2005-01-01

Metallic amorphous materials have been widely developed thanks to the outstanding properties including high chemical stability, mechanical strength, and magnetic properties. However, with the exception of a few compositions, the limiting factor is the critical cooling rate for the formation of the amorphous phase. For many applications, it is only the contact surface properties that are important, thus the use, of coating techniques such as thermal sprayings has several attractive features. In this paper, we present the microstructure of Ni-based amorphous coatings prepared by laser cladding and vacuum plasma spraying. The utilization of plasma spraying to deposit atomized powder enabled the formation of fully amorphous coating, laser cladding resulted in mostly crystallized structures. Glass forming ability and wear properties of the coatings were discussed as a function of the coating microstructure. (orig.)

LiFAP-based PVdF-HFP microporous membranes by phase-inversion technique with Li/LiFePO{sub 4} cell

Energy Technology Data Exchange (ETDEWEB)

Aravindan, V.; Vickraman, P. [Gandhigram Rural University, Department of Physics, Gandhigram (India); Sivashanmugam, A.; Thirunakaran, R.; Gopukumar, S. [Central Electrochemical Research Institute, Electrochemical Energy Systems Division, Karaikudi (India)

2009-12-15

Polyvinylidenefluoride-hexafluoropropylene-based (PVdF-HFP-based) gel and composite microporous membranes (GPMs and CPMs) were prepared by phase-inversion technique in the presence 10 wt% of AlO(OH){sub n} nanoparticles. The prepared membranes were gelled with 0.5-M LiPF{sub 3}(CF{sub 2}CF{sub 3}){sub 3} (lithium fluoroalkylphosphate, LiFAP) in EC:DEC (1:1 v/v) and subjected to various characterizations; the AC impedance study shows that CPMs exhibit higher conductivity than GPMs. Mechanical stability measurements on these systems reveal that CPMs exhibit Young's modulus higher than that of bare and GPMs and addition of nanoparticles drastically improves the elongation break was also noted. Transition of the host from {alpha} to {beta} phase after the loading of nanosized filler was confirmed by XRD and Raman studies. Physico-chemical properties, like liquid uptake, porosity, surface area, and activation energy, of the membranes were calculated and results are summarized. Cycling performance of Li/CPM/LiFePO{sub 4} coin cell was fabricated and evaluated at C/10 rate and delivered a discharge capacity of 157 and 148 mAh g {sup -1} respectively for first and tenth cycles. (orig.)

Gamma, X-ray and neutron techniques for the coal industry

International Nuclear Information System (INIS)

1986-01-01

Nuclear techniques play a prominent role in all aspects of the coal industry, from exploration through mine development to testing of coal quality during production. The advent of on-line nuclear techniques allows continuous, near real time appraisal of coal quality free from the errors inherent in conventional techniques based on discrete samples. The Advisory Group Meeting reviews the latest developments in this area and makes recommendations on the most promising areas and priorities for future research and development activities. This report records the proceedings of the Advisory Group Meeting. Separate abstracts were prepared for each of the 13 papers in this report

Analytical research using synchrotron radiation based techniques

International Nuclear Information System (INIS)

Jha, Shambhu Nath

2015-01-01

There are many Synchrotron Radiation (SR) based techniques such as X-ray Absorption Spectroscopy (XAS), X-ray Fluorescence Analysis (XRF), SR-Fourier-transform Infrared (SRFTIR), Hard X-ray Photoelectron Spectroscopy (HAXPS) etc. which are increasingly being employed worldwide in analytical research. With advent of modern synchrotron sources these analytical techniques have been further revitalized and paved ways for new techniques such as microprobe XRF and XAS, FTIR microscopy, Hard X-ray Photoelectron Spectroscopy (HAXPS) etc. The talk will cover mainly two techniques illustrating its capability in analytical research namely XRF and XAS. XRF spectroscopy: XRF spectroscopy is an analytical technique which involves the detection of emitted characteristic X-rays following excitation of the elements within the sample. While electron, particle (protons or alpha particles), or X-ray beams can be employed as the exciting source for this analysis, the use of X-ray beams from a synchrotron source has been instrumental in the advancement of the technique in the area of microprobe XRF imaging and trace level compositional characterisation of any sample. Synchrotron radiation induced X-ray emission spectroscopy, has become competitive with the earlier microprobe and nanoprobe techniques following the advancements in manipulating and detecting these X-rays. There are two important features that contribute to the superb elemental sensitivities of microprobe SR induced XRF: (i) the absence of the continuum (Bremsstrahlung) background radiation that is a feature of spectra obtained from charged particle beams, and (ii) the increased X-ray flux on the sample associated with the use of tunable third generation synchrotron facilities. Detection sensitivities have been reported in the ppb range, with values of 10 -17 g - 10 -14 g (depending on the particular element and matrix). Keeping in mind its demand, a microprobe XRF beamline has been setup by RRCAT at Indus-2 synchrotron

Study on Gas Sensing Performance of In2O3 Thick Film Resistors Prepared by Screen Printing Technique

Directory of Open Access Journals (Sweden)

S. C. KULKARNI

2011-02-01

Full Text Available Indium Oxide (In2O3 thick films were prepared on alumina substrate by using standard screen printing technique. These films were dried and fired at temperatures between 750 0C to 950 0C for two hours in air atmosphere. The compositional, morphological and structural properties of In2O3 films were performed by Energy Dispersive Spectroscopy (EDX, XRD, and Scanning electron Microscopy respectively. We explore the various gases to study sensing performance of In2O3 thick films. The maximum response was reported to film fired at 750 0C for H2S gas at 150 0C operating temperature.

Preparation of electrodes on cfrp composites with low contact resistance comprising laser-based surface pre-treatment

KAUST Repository

Almuhammadi, Khaled Hamdan

2016-12-29

Various examples are provided related to the preparation of electrodes on carbon fiber reinforced polymer (CFRP) composites with low contact resistance. Laser-based surface preparation can be used for bonding to CFRP composites. In one example, a method includes preparing a pretreated target area on a CFRP composite surface using laser pulsed irradiation and bonding an electrode to exposed fibers in the pretreated target area. The surface preparation can allow the electrode to have a low contact resistance with the CFRP composite.

Fractal Image Compression Based on High Entropy Values Technique

Directory of Open Access Journals (Sweden)

Douaa Younis Abbaas

2018-04-01

Full Text Available There are many attempts tried to improve the encoding stage of FIC because it consumed time. These attempts worked by reducing size of the search pool for pair range-domain matching but most of them led to get a bad quality, or a lower compression ratio of reconstructed image. This paper aims to present a method to improve performance of the full search algorithm by combining FIC (lossy compression and another lossless technique (in this case entropy coding is used. The entropy technique will reduce size of the domain pool (i. e., number of domain blocks based on the entropy value of each range block and domain block and then comparing the results of full search algorithm and proposed algorithm based on entropy technique to see each of which give best results (such as reduced the encoding time with acceptable values in both compression quali-ty parameters which are C. R (Compression Ratio and PSNR (Image Quality. The experimental results of the proposed algorithm proven that using the proposed entropy technique reduces the encoding time while keeping compression rates and reconstruction image quality good as soon as possible.

Preparation of Affinity Column Based on Zr{sup 4+} Ion for Phosphoproteins Isolation

Energy Technology Data Exchange (ETDEWEB)

Lee, Seon Mi; Bae, In Ae; Park, Jung Hyen; Kim, Tae Dong; Choi, Seong Ho [Hannam University, Daejeon (Korea, Republic of)

2009-06-15

This paper has described about preparation of Zr{sup 4+} affinity column based on the poly(styreneco- glycidyl methacrylate) prepared by emulsion polymerization of styrene and glycidyl methacrylate in order to isolate phosphopeptide. The Zr{sup 4+} ions were introduced after the phophonation of an epoxy group on polymeric microspheres. The successful preparation of Zr{sup 4+}-immobilized polymeric microsphere stationary phase was confirmed through Fourier transform infrared spectra, optical microscopy, scanning electron microscopy, X-ray photoelectron spectra and inductively coupled plasma-atomic emission spectrometer. The separation efficiency for Zr{sup 4+} affinity column prepared by slurry packing was tested to phosphonated casein and dephosphonated casein. The resolution time (min) of the phosphonated casein was higher than that of dephosphated casein for Zr{sup 4+} affinity polymeric microsphere by liquid chromatography. This Zr{sup 4+} affinity column can be used for isolation of phosphonated casein from casein using liquid chromatography.

Preparation of trialkylindium by alkylation of metallic indium

International Nuclear Information System (INIS)

Eremeev, I.V.; Danov, S.M.; Sakhipov, V.R.

1995-01-01

The investigation results on production of trialkyl indium by alkylation of metallic indium are presented. In contradistinction to the known techniques for the production of trialkyls on indium by alkylation it is suggested to separate the synthesis into two steps. At the first step indium is alkylated by alkylhalide to alkyl indium halide, and at the second alkylation is carried out using. Grignard reagent. The techniques for preparation of trimethyl- and triethylindium, developed on the bases of this scheme, are noted for good reproducibility, allow to preclude, agglomeration of indium during the synthesis, as well as to reduce the consumption coefficients, and amounts, of the introduced starting reagents, i.e. magnesium and alkylhalide. Refs. 16

Preparation of electrodes on cfrp composites with low contact resistance comprising laser-based surface pre-treatment

KAUST Repository

Almuhammadi, Khaled Hamdan; Lubineau, Gilles; Alfano, Marco Francesco; Buttner, Ulrich

2016-01-01

Various examples are provided related to the preparation of electrodes on carbon fiber reinforced polymer (CFRP) composites with low contact resistance. Laser-based surface preparation can be used for bonding to CFRP composites. In one example, a

Preparing facilitators from community-based organizations for evidence-based intervention training in Second Life.

Science.gov (United States)

Valladares, Angel Felix; Aebersold, Michelle; Tschannen, Dana; Villarruel, Antonia Maria

2014-09-30

A major barrier to the use and scale-up of evidence-based interventions are challenges related to training and capacity building. A cost-effective and highly interactive multi-user virtual environment, Second Life (SL) is a promising alternative for comprehensive face-to-face facilitator training. The purpose of this study was to examine the feasibility of using SL to train facilitators from community-based organizations to use ¡Cuídate! (Take Care of Yourself), one of the few evidence-based interventions developed and tested with Latino youth to reduce sexual risk behaviors. We recruited 35 participants from community-based organizations throughout the United States to participate in the SL ¡Cuídate! Training of Facilitators. Preparation to use SL consisted of four phases: (1) recruitment and computer capacity screening, (2) enrollment, (3) orientation to the SL program, and (4) technical support throughout the synchronous training sessions. Technical difficulties, the associated cause, and the mitigation strategy implemented were recorded during each session. Participants completed evaluations including perceptions of self-efficacy and confidence to complete the necessary skills to participate in SL training. Overall, participants reported high levels of self-efficacy for all skills necessary to participate in SL training. Based on an 11-point scale (0-10), self-efficacy to download and access the software was rated the highest: mean 8.29 (SD 2.19). Interacting with items in SL had the lowest mean score: mean 7.49 (SD 2.89). The majority of technical difficulties experienced by participants were related to inadequate Internet connections or computer malfunctions. Our findings support the feasibility of using SL for the ¡Cuídate! Training of Facilitators. The process used in this study to prepare participants to use SL can be used as a basis for other evidence-based intervention training in SL. This study is an important contribution to developing cost

Bevacizumab loaded solid lipid nanoparticles prepared by the coacervation technique: preliminary in vitro studies

Science.gov (United States)

Battaglia, Luigi; Gallarate, Marina; Peira, Elena; Chirio, Daniela; Solazzi, Ilaria; Giordano, Susanna Marzia Adele; Gigliotti, Casimiro Luca; Riganti, Chiara; Dianzani, Chiara

2015-06-01

Glioblastoma, the most common primary brain tumor in adults, has an inauspicious prognosis, given that overcoming the blood-brain barrier is the major obstacle to the pharmacological treatment of brain tumors. As neoangiogenesis plays a key role in glioblastoma growth, the US Food and Drug Administration approved bevacizumab (BVZ), an antivascular endothelial growth factor antibody for the treatment of recurrent glioblastoma in patients whose the initial therapy has failed. In this experimental work, BVZ was entrapped in solid lipid nanoparticles (SLNs) prepared by the fatty-acid coacervation technique, thanks to the formation of a hydrophobic ion pair. BVZ activity, which was evaluated by means of four different in vitro tests on HUVEC cells, increased by 100- to 200-fold when delivered in SLNs. Moreover, SLNs can enhance the permeation of fluorescently labelled BVZ through an hCMEC/D3 cell monolayer—an in vitro model of the blood brain barrier. These results are promising, even if further in vivo studies are required to evaluate the effective potential of BVZ-loaded SLNs in glioblastoma treatment.

Intelligent control and maintenance of management integrated system based on multi-agents for coal preparation plant

Energy Technology Data Exchange (ETDEWEB)

Meng, F.; Wang, Y. [China University of Mining and technology, Xuzhou (China). School of Information and Electrical Engineering

2006-06-15

This paper discusses the progress of computer integrated processing (CIPS) of coal preparation and then presents an intelligence controlled production process, device-maintenance and production-management system of coal preparation based on multi-agents (IICMMS-CP). The construction of the IICMMS-CP, the distributed network control system based on live intelligence control stations and the strategy of implementing a distributed intelligence control system are studied in order to overcome the disadvantages brought about by the wide use of the PLC system by coal preparation plants. The software frame, based on a Multi-Agent Intelligence Control and Maintenance Management integrated system, is studied and the implementation methods of IICMMS-CP are discussed. The characteristics of distributed architecture, cooperation and parallel computing meet the needs of integrated control of coal preparation plants with large-scale spatial production distribution, densely-related processes and complex systems. Its application further improves the reliability and precision of process control, accuracy of fault identification and intelligence of production adjustment, establishes a technical basis for system integration and flexible production. The main function of the system has been tested in a coal preparation plant to good effect in stabilizing product quality, improving efficiency and reducing consumption. 17 refs., 4 figs.

Preparation and physicochemical of microemulsion based on macadamia nut oil

Science.gov (United States)

Tu, Xinghao; Chen, Hong; Du, Liqing

2018-03-01

The objective of the present work was to study the preparation, optimization and characteristic of nanostructured lipid carriers(NLCs) based on macadamia nut oil. NLC with various macadamia nut oil content were successfully prepared by an optimized microfluidization method using stearic acid as solid lipid and pluronic F68 as surfactant. As a result, NLC with particle size about 286nm were obtained, and the polydispersity index(PI) of all developed NLC were below 0.2 which indicate a narrow size distribution. Furthermore, the encapsulation efficiency and loading capability were investigated as well. Physical stability of NLC demonstrated that particles of system were stable at room temperature and low temperature. Differential scanning calorimetry(DSC) investigation show that the inner structure and recrystallinity of lipid matrix within NLC were greatly influenced by the content of macadamia nut oil.

Auto-correlation based intelligent technique for complex waveform presentation and measurement

International Nuclear Information System (INIS)

Rana, K P S; Singh, R; Sayann, K S

2009-01-01

Waveform acquisition and presentation forms the heart of many measurement systems. Particularly, data acquisition and presentation of repeating complex signals like sine sweep and frequency-modulated signals introduces the challenge of waveform time period estimation and live waveform presentation. This paper presents an intelligent technique, for waveform period estimation of both the complex and simple waveforms, based on the normalized auto-correlation method. The proposed technique is demonstrated using LabVIEW based intensive simulations on several simple and complex waveforms. Implementation of the technique is successfully demonstrated using LabVIEW based virtual instrumentation. Sine sweep vibration waveforms are successfully presented and measured for electrodynamic shaker system generated vibrations. The proposed method is also suitable for digital storage oscilloscope (DSO) triggering, for complex signals acquisition and presentation. This intelligence can be embodied into the DSO, making it an intelligent measurement system, catering wide varieties of the waveforms. The proposed technique, simulation results, robustness study and implementation results are presented in this paper.

Mechanical properties of anorthite based ceramics prepared from kaolin DD2 and calcite

Energy Technology Data Exchange (ETDEWEB)

Harabi, A.; Zaiou, S.; Guechi, A.; Foughali, L.; Harabi, E.; Karboua, N.-E.; Zouai, S.; Mezahi, F.-Z.; Guerfa, F., E-mail: harabi52@gmail.com, E-mail: Zaiou_21@yahoo.fr, E-mail: guechia@yahoo.fr, E-mail: semouni84@gmail.com, E-mail: kanour17@yahoo.fr, E-mail: foughali_lazhar@yahoo.fr, E-mail: zouaisouheila@yahoo.fr, E-mail: mezahif@yahoo.fr [Ceramics Lab., Faculty of Exact Science, Physics Department, Mentouri University of Constantine (Algeria)

2017-07-15

Good quality ceramics costs a lot that has limited their use in developing countries. This work was devoted to prepare low-cost and good quality anorthite based ceramics. The proposed composition was 80 wt% kaolin (DD2 type) and 20 wt% calcium oxide (CaO). The choice of these raw materials was dictated by their natural abundance coupled with a modified milling system, as another interesting advantage. Previous studies have shown that a simple vibratory multidirectional milling system using bimodal distribution of highly resistant ceramic milling elements has been successfully applied for obtaining fine powders. The influence of the relatively lower sintering temperature, ranging from 800 to 1100 °C, on the porosity and the average pore size (APS) have been investigated. The APS and the porosity values of samples sintered at 950 °C were about 1 μm and 4%, respectively. The best Vickers microhardness and 3-point bending strength values for these sintered samples, using this proposed milling system, were 7.1 GPa and 203 MPa, respectively. Finally, the crystalline phase evolution during heat treatment was investigated by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques. (author)

Ultra fine grained Ti prepared by severe plastic deformation

Science.gov (United States)

Lukáč, F.; Čížek, J.; Knapp, J.; Procházka, I.; Zháňal, P.; Islamgaliev, R. K.

2016-01-01

The positron annihilation spectroscopy was employed for characterisation of defects in pure Ti with ultra fine grained (UFG) structure. UFG Ti samples were prepared by two techniques based on severe plastic deformation (SPD): (i) high pressure torsion (HPT) and (ii) equal channel angular pressing (ECAP). Although HPT is the most efficient technique for grain refinement, the size of HPT-deformed specimens is limited. On the other hand, ECAP is less efficient in grain refinement but enables to produce larger samples more suitable for industrial applications. Characterisation of defects by positron annihilation spectroscopy was accompanied by hardness testing in order to monitor the development of mechanical properties of UFG Ti.

Conditions of development of professional competence by preparation of the teacher in the field of a technique of training to computer science

Directory of Open Access Journals (Sweden)

Ольга Юрьевна Заславская

2009-12-01

Full Text Available In article results of research of formation of professional competence of teachers of computer science in modern conditions of modernization of an education system are described. In the conditions of formation information, it is necessary to carry out preparation of the teacher possessing administrative competence, necessary quality first of all in the course of training of the theory and a technique of training to computer science.

Line impedance estimation using model based identification technique

DEFF Research Database (Denmark)

Ciobotaru, Mihai; Agelidis, Vassilios; Teodorescu, Remus

2011-01-01

The estimation of the line impedance can be used by the control of numerous grid-connected systems, such as active filters, islanding detection techniques, non-linear current controllers, detection of the on/off grid operation mode. Therefore, estimating the line impedance can add extra functions...... into the operation of the grid-connected power converters. This paper describes a quasi passive method for estimating the line impedance of the distribution electricity network. The method uses the model based identification technique to obtain the resistive and inductive parts of the line impedance. The quasi...

Graph based techniques for tag cloud generation

DEFF Research Database (Denmark)

Leginus, Martin; Dolog, Peter; Lage, Ricardo Gomes

2013-01-01

Tag cloud is one of the navigation aids for exploring documents. Tag cloud also link documents through the user defined terms. We explore various graph based techniques to improve the tag cloud generation. Moreover, we introduce relevance measures based on underlying data such as ratings...... or citation counts for improved measurement of relevance of tag clouds. We show, that on the given data sets, our approach outperforms the state of the art baseline methods with respect to such relevance by 41 % on Movielens dataset and by 11 % on Bibsonomy data set....

Hard dental tissue minimal-invasive preparation using contemporary polymer rotating instruments and laser

OpenAIRE

Beloica Miloš; Vulićević Zoran R.; Mandinić Zoran; Radović Ivana; Jovičić Olivera; Carević Momir; Tekić Jasmina

2014-01-01

Goal of contemporary dentistry is to decrease the patient’s discomfort during treatment. Dentists aim to achieve maximum with the newly developed dental materials as well as with new cavity preparation techniques in the shortest time span. Since the development of the first constructed borer (drilling machine) for caries removal, the preparation techniques have considerably changed. The progress of dental materials as well as the cavity preparation techniqu...

Backstepping Based Formation Control of Quadrotors with the State Transformation Technique

Directory of Open Access Journals (Sweden)

Keun Uk Lee

2017-11-01

Full Text Available In this paper, a backstepping-based formation control of quadrotors with the state transformation technique is proposed. First, the dynamics of a quadrotor is derived by using the Newton–Euler formulation. Next, a backstepping-based formation control for quadrotors using a state transformation technique is presented. In the position control, which is the basis of formation control, it is possible to derive the reference attitude angles employing a state transformation technique without the small angle assumption or the simplified dynamics usually used. Stability analysis based on the Lyapunov theorem shows that the proposed formation controller can provide a quadrotor formation error system that is asymptotically stabilized. Finally, we verify the performance of the proposed formation control method through comparison simulations.

Preparation of Drug-loaded Chitosan Microspheres and Its Application in Paper-based PVC Wallpaper