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Sample records for revisited matrix evaluation

  1. Revisiting Superintendent Evaluation

    ERIC Educational Resources Information Center

    DiPaola, Michael F.

    2007-01-01

    Superintendents' performance evaluations continue to be too frequently conducted through a highly informal, subjective process, based more on impressions than data. Several states require school boards to use student performance data in evaluating their superintendents. Student achievement data, focusing on continuous improvement, should certainly…

  2. Extracellular Matrix Revisited: Roles in Tissue Engineering

    PubMed Central

    2016-01-01

    The extracellular matrix (ECM) is a heterogeneous, connective network composed of fibrous glycoproteins that coordinate in vivo to provide the physical scaffolding, mechanical stability, and biochemical cues necessary for tissue morphogenesis and homeostasis. This review highlights some of the recently raised aspects of the roles of the ECM as related to the fields of biophysics and biomedical engineering. Fundamental aspects of focus include the role of the ECM as a basic cellular structure, for novel spontaneous network formation, as an ideal scaffold in tissue engineering, and its essential contribution to cell sheet technology. As these technologies move from the laboratory to clinical practice, they are bound to shape the vast field of tissue engineering for medical transplantations. PMID:27230457

  3. Revisiting the Role of Organizational Effectiveness in Educational Evaluation.

    ERIC Educational Resources Information Center

    Lotto, Linda S.

    Organizational effectiveness ought to play a role in educational evaluation, and the development of alternative perspectives for viewing organizations could be a starting point for revisiting organizational evaluation in education. Five possible perspectives and criteria for evaluating organizations have been developed. If an organization is…

  4. The functional matrix hypothesis revisited. 3. The genomic thesis.

    PubMed

    Moss, M L

    1997-09-01

    Although the initial versions of the functional matrix hypothesis (FMH) theoretically posited the ontogenetic primacy of "function," it is only in recent years that advances in the morphogenetic, engineering, and computer sciences provided an integrated experimental and numerical data base that permitted recent significant revisions of the FMH--revisions that strongly support the primary role of function in craniofacial growth and development. Acknowledging that the currently dominant scientific paradigm suggests that genomic, instead of epigenetic (functional) factors, regulate (cause, control) such growth, an analysis of this continuing controversy was deemed useful. Accordingly the method of dialectical analysis, is employed, stating a thesis, an antithesis, and a resolving synthesis based primarily on an extensive review of the pertinent current literature. This article extensively reviews the genomic hypothesis and offers a critique intended to remove some of the unintentional conceptual obscurantism that has recently come to surround it. PMID:9294365

  5. Evaluation of metal matrix composites

    NASA Technical Reports Server (NTRS)

    Okelly, K. P.

    1971-01-01

    The results of an evaluation of candidate metal-matrix composite materials for shuttle space radiators mounted to external structure are presented. The evaluation was specifically applicable to considerations of the manufacturing and properties of a potential space radiator. Two candidates, boron/aluminum and graphite/aluminum were obtained or made in various forms and tested in sufficient depth to allow selection of one of the two for future scale-up programs. The effort accomplished on this program verified that aluminum reinforced with boron was within the state-of-the-art in industry and possessed properties usable in the external skin areas available for shuttle radiators where re-entry temperatures will not exceed 800 F. It further demonstrated that graphite/aluminum has an apparently attractive future for space applications but requires extension development prior to scale-up.

  6. Evaluation Methods for Intelligent Tutoring Systems Revisited

    ERIC Educational Resources Information Center

    Greer, Jim; Mark, Mary

    2016-01-01

    The 1993 paper in "IJAIED" on evaluation methods for Intelligent Tutoring Systems (ITS) still holds up well today. Basic evaluation techniques described in that paper remain in use. Approaches such as kappa scores, simulated learners and learning curves are refinements on past evaluation techniques. New approaches have also arisen, in…

  7. PlanJury: probabilistic plan evaluation revisited

    NASA Astrophysics Data System (ADS)

    Witte, M.; Sonke, J.-J.; van Herk, M.

    2014-03-01

    Purpose: Over a decade ago, the 'Van Herk margin recipe paper' introduced plan evaluation through DVH statistics based on population distributions of systematic and random errors. We extended this work for structures with correlated uncertainties (e.g. lymph nodes or parotid glands), and considered treatment plans containing multiple (overlapping) dose distributions (e.g. conventional lymph node and hypo-fractionated tumor doses) for which different image guidance protocols may lead to correlated errors. Methods: A command-line software tool 'PlanJury' was developed which reads 3D dose and structure data exported from a treatment planning system. Uncertainties are specified by standard deviations and correlation coefficients. Parameters control the DVH statistics to be computed: e.g. the probability of reaching a DVH constraint, or the dose absorbed at given confidence in a (combined) volume. Code was written in C++ and parallelized using OpenMP. Testing geometries were constructed using idealized spherical volumes and dose distributions. Results: Negligible stochastic noise could be attained within two minutes computation time for a single target. The confidence to properly cover both of two targets was 90% for two synchronously moving targets, but decreased by 7% if the targets moved independently. For two partially covered organs at risk the confidence of at least one organ below the mean dose threshold was 40% for synchronous motion, 36% for uncorrelated motion, but only 20% for either of the organs separately. Two abutting dose distributions ensuring 91% confidence of proper target dose for correlated motions led to 28% lower confidence for uncorrelated motions as relative displacements between the doses resulted in cold spots near the target. Conclusions: Probabilistic plan evaluation can efficiently be performed for complicated treatment planning situations, thus providing important plan quality information unavailable in conventional PTV based evaluations.

  8. Revisiting the S-matrix approach to the open superstring low energy effective lagrangian

    NASA Astrophysics Data System (ADS)

    Barreiro, Luiz Antonio; Medina, Ricardo

    2012-10-01

    The conventional S-matrix approach to the (tree level) open string low energy effective lagrangian assumes that, in order to obtain all its bosonic α ' N order terms, it is necessary to know the open string (tree level) ( N + 2)-point amplitude of massless bosons, at least expanded at that order in α '. In this work we clarify that the previous claim is indeed valid for the bosonic open string, but for the supersymmetric one the situation is much more better than that: there are constraints in the kinematical bosonic terms of the amplitude (probably due to Spacetime Supersymmetry) such that a much lower open superstring n-point amplitude is needed to find all the α ' N order terms. In this `revisited' S-matrix approach we have checked that, at least up to α '4 order, using these kinematical constraints and only the known open superstring 4-point amplitude, it is possible to determine all the bosonic terms of the low energy effective lagrangian. The sort of results that we obtain seem to agree completely with the ones achieved by the method of BPS configurations, proposed about ten years ago. By means of the KLT relations, our results can be mapped to the NS-NS sector of the low energy effective lagrangian of the type II string theories implying that there one can also find kinematical constraints in the N-point amplitudes and that important informations can be inferred, at least up to α '4 order, by only using the (tree level) 4-point amplitude.

  9. Graphical evaluation of relativistic matrix elements

    NASA Technical Reports Server (NTRS)

    Huang, K. N.

    1978-01-01

    A graphical representation of angular momentum was used to evaluate relativistic matrix elements between antisymmetrized states of many particle configurations having any number of open shells. The antisymmetrized matrix element was expanded as a sum of semisymmetrized matrix elements. The diagram representing a semisymmetrized matrix element was composed of four diagram blocks; the bra block, the ket block, the spectator block, and the interaction block. The first three blocks indicate the couplings of the two interacting configurations while the last depends on the interaction and is the replaceable component. Interaction blocks for relativistic operators and commonly used potentials were summarized in ready to use forms. A simple step by step procedure was prescribed generally for calculating antisymmetrized matrix elements of one and two particle operators.

  10. Matrix evaluation of science objectives

    NASA Technical Reports Server (NTRS)

    Wessen, Randii R.

    1994-01-01

    The most fundamental objective of all robotic planetary spacecraft is to return science data. To accomplish this, a spacecraft is fabricated and built, software is planned and coded, and a ground system is designed and implemented. However, the quantitative analysis required to determine how the collection of science data drives ground system capabilities has received very little attention. This paper defines a process by which science objectives can be quantitatively evaluated. By applying it to the Cassini Mission to Saturn, this paper further illustrates the power of this technique. The results show which science objectives drive specific ground system capabilities. In addition, this process can assist system engineers and scientists in the selection of the science payload during pre-project mission planning; ground system designers during ground system development and implementation; and operations personnel during mission operations.

  11. Evaluation of the Matrix Project. Interchange 77.

    ERIC Educational Resources Information Center

    McIvor, Gill; Moodie, Kristina

    The Matrix Project is a program that has been established in central Scotland with the aim of reducing the risk of offending and anti-social behavior among vulnerable children. The project provides a range of services to children between eight and 11 years of age who are at risk in the local authority areas of Clackmannanshire, Falkirk and…

  12. Complicity Revisited: Balancing Stakeholder Input and Roles in Evaluation Use

    ERIC Educational Resources Information Center

    Sturges, Keith M.

    2015-01-01

    Drawing on a qualitative study of an educational reform and its external evaluation, I describe how a well-intentioned but poorly conceptualized evaluation helped perpetuate asymmetries in the generation and use of evaluation findings. This article explores this project's failure to clarify evaluator roles, identify intended users and expected…

  13. Lakatos Revisited.

    ERIC Educational Resources Information Center

    Court, Deborah

    1999-01-01

    Revisits and reviews Imre Lakatos' ideas on "Falsification and the Methodology of Scientific Research Programmes." Suggests that Lakatos' framework offers an insightful way of looking at the relationship between theory and research that is relevant not only for evaluating research programs in theoretical physics, but in the social sciences as…

  14. Entrepreneurship Education Evaluation: Revisiting Storey to Hunt for the "Heffalump"

    ERIC Educational Resources Information Center

    Henry, Colette

    2015-01-01

    Purpose: The purpose of this paper is to consider entrepreneurship education (EE) evaluation. Specifically, it explores some of the challenges involved in applying the "HEInnovate" tool, and considers ways in which its accuracy and value might be strengthened. Using Storey (2000) by way of reflective critique, the paper proposes an…

  15. Preventing Groupthink Revisited: Evaluating and Reforming Groups in Government.

    PubMed

    Hart

    1998-02-01

    This article critically examines Janis's recommendations for preventing groupthink in high-level policymaking. It puts forward three models of small group functioning in government, each of which highlights different dimensions of collegial policymaking and distinct criteria for evaluating group performance. Each model also inspires different proposals for groupthink prevention and improvement of group performance in general. Proposals for designing and managing high-level groups in government need to take into account these multiple perspectives. Furthermore, their proponents should be aware of the institutionalized and competitive context in which political decision groups operate. Evaluations of their performance and proposals for reforming them are inevitably tied up in this process. This has important implications for the feasibility of recommendations set forth by small group analysts. The article concludes with an agenda for increasing the policy relevance and practical feasibility of research on political decision groups. Copyright 1998 Academic Press. PMID:9705806

  16. Evaluation of waterjet-machined metal matrix composite tensile specimens

    SciTech Connect

    Lavender, C.A.; Smith, M.T.

    1986-04-01

    Four magnesium/boron carbide metal matrix composite (MMC) tensile specimens fabricated using the waterjet machining method were evaluated in order to determine the effects of the waterjet material removal process on the composite material surface structure and properties. These results were then compared with data from material conventionally machined. Results showed that while waterjet cutting produces a rough surface finish and does not meet specified dimensional tolerances, the technique appears to be suitable for sectioning and rough machining of metal matrix composites.

  17. Evaluation of 2D ceramic matrix composites in aeroconvective environments

    NASA Technical Reports Server (NTRS)

    Riccitiello, Salvatore R.; Love, Wendell L.; Balter-Peterson, Aliza

    1992-01-01

    An evaluation is conducted of a novel ceramic-matrix composite (CMC) material system for use in the aeroconvective-heating environments encountered by the nose caps and wing leading edges of such aerospace vehicles as the Space Shuttle, during orbit-insertion and reentry from LEO. These CMCs are composed of an SiC matrix that is reinforced with Nicalon, Nextel, or carbon refractory fibers in a 2D architecture. The test program conducted for the 2D CMCs gave attention to their subsurface oxidation.

  18. The MATRIX study: evaluating the data in older adults.

    PubMed

    Newman, Diane K

    2008-01-01

    In summary, the MATRIX study evaluated the use of OXY-TDS in older adults residing in community settings. Although it was a community-based study, a large segment of those studied had traits similar to those residing in long-term care settings--699 patients were aged 75 years or older; many had comorbid diseases; and many had a long history of OAB. MATRIX found that the transdermal form of oxybutynin was a safe and effective method to manage OAB in this older population. Adverse events reported were minor and local, with the most common event being local skin irritation. The transdermal formulation improved the symptoms associated with OAB and improved QOL. Although nursing home residents were not studied in MATRIX, it appears that the transdermal formulation of oxybutynin would be an agent of choice in older adults. PMID:19343887

  19. Process-interactive nondestructive evaluation for metal-matrix composites

    NASA Astrophysics Data System (ADS)

    Liaw, P. K.; Shannon, R. E.; Clark, W. G., Jr.; Harrigan, W. C., Jr.

    Nondestructive evaluation (NDE) has been conducted on composite products at various stages of fabrication processes including raw powders, powder mixtures, billets and final product extrusions. Eddy current was found to be effective in identifying matrix powder alloy chemistry and particle size, and in determining the mix ratio of silicon carbide (SiC) reinforcement particles in aluminum matrix alloy powders. Ultrasonic techniques were capable of identifying SiC clusters in large-scale, consolidated powder metallurgy (P/M) metal matrix composite (MMC) billets, while eddy current methods could be used to determine near-surface density variations in the billets. Multiple NDE techniques (eddy current, ultrasonics and resistivity) could be employed to quantify microstructural characteristics of composite extrusions. These results suggest that NDE methods can be integrated into manufacturing processes to provide online, closed-loop control of fabrication parameters.

  20. Evaluating wilderness recreational opportunities: application of an impact matrix

    USGS Publications Warehouse

    Stohlgren, Thomas J.; Parsons, David J.

    1992-01-01

    An inventory of the severity and spatial distribution of wilderness campsite impacts in Sequoia and Kings Canyon National Parks identified a total of 273 distinct nodes of campsites or “management areas.” A campsite impact matrix was developed to evaluate management areas based on total impacts (correlated to the total area of campsite development) and the density, or concentration, of impacts relative to each area's potentially campable area. The matrix is used to quantify potential recreational opportunities for wilderness visitors in a spectrum from areas offering low impact-dispersed camping to those areas offering high impact-concentrated camping. Wilderness managers can use this type of information to evaluate use distribution patterns, identify areas to increase or decrease use, and to identify areas needing site-specific regulations (e.g., one-night camping limits) to preserve wilderness resources and guarantee outstanding opportunities for solitude.

  1. Revisiting the block method for evaluating thermal conductivities of clay and granite

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Determination of thermal conductivities of porous media using the contact method is revisited and revalidated with consideration of thermal contact resistance. Problems that limit the accuracy of determination of thermal conductivities of porous media are discussed. Thermal conductivities of granite...

  2. Flanking p10 contribution and sequence bias in matrix based epitope prediction: revisiting the assumption of independent binding pockets

    PubMed Central

    Parry, Christian S

    2008-01-01

    Background Eluted natural peptides from major histocompatibility molecules show patterns of conserved residues. Crystallographic structures show that the bound peptide in class II major histocompatibility complex adopts a near uniform polyproline II-like conformation. This way allele-specific favoured residues are able to anchor into pockets in the binding groove leaving other peptide side chains exposed for recognition by T cells. The anchor residues form a motif. This sequence pattern can be used to screen large sequences for potential epitopes. Quantitative matrices extend the motif idea to include the contribution of non-anchor peptide residues. This report examines two new matrices that extend the binding register to incorporate the polymorphic p10 pocket of human leukocyte antigen DR1. Their performance is quantified against experimental binding measurements and against the canonical nine-residue register matrix. Results One new matrix shows significant improvement over the base matrix; the other does not. The new matrices differ in the sequence of the peptide library. Conclusion One of the extended quantitative matrices showed significant improvement in prediction over the original nine residue matrix and over the other extended matrix. Proline in the sequence of the peptide library of the better performing matrix presumably stabilizes the peptide conformation through neighbour interactions. Such interactions may influence epitope prediction in this test of quantitative matrices. This calls into question the assumption of the independent contribution of individual binding pockets. PMID:18925947

  3. Nonnegative matrix factorization for the identification of EMG finger movements: evaluation using matrix analysis.

    PubMed

    Naik, Ganesh R; Nguyen, Hung T

    2015-03-01

    Surface electromyography (sEMG) is widely used in evaluating the functional status of the hand to assist in hand gesture recognition, prosthetics and rehabilitation applications. The sEMG is a noninvasive, easy to record signal of superficial muscles from the skin surface. Considering the nonstationary characteristics of sEMG, recent feature selection of hand gesture recognition using sEMG signals necessitate designers to use nonnegative matrix factorization (NMF)-based methods. This method exploits both the additive and sparse nature of signals by extracting accurate and reliable measurements of sEMG features using a minimum number of sensors. The testing has been conducted for simple and complex finger flexions using several experiments with artificial neural network classification scheme. It is shown, both by simulation and experimental studies, that the proposed algorithm is able to classify ten finger flexions (five simple and five complex finger flexions) recorded from two sEMG sensors up to 92% (95% for simple and 87% for complex flexions) accuracy. The recognition performances of simple and complex finger flexions are also validated with NMF permutation matrix analysis. PMID:25486650

  4. Acousto-ultrasonic evaluation of ceramic matrix composite materials

    NASA Technical Reports Server (NTRS)

    Dosreis, Henrique L. M.

    1991-01-01

    Acousto-ultrasonic nondestructive evaluation of ceramic composite specimens with a lithium-alumino-silicate glass matrix reinforced with unidirectional silicon carbide (NICALON) fibers was conducted to evaluate their reserve of strength. Ceramic composite specimens with different amount of damage were prepared by four-point cyclic fatigue loading of the specimens at 500 C for a different number of cycles. The reserve of strength of the specimens was measured as the maximum bending stress recorded during four-pointed bending test with the load monotonically increased until failure occurs. It was observed that the reserve of strength did not correlate with the number of fatigue cycles. However, it was also observed that higher values of the stress wave factor measurements correspond to higher values of the reserve of strength test data. Therefore, these results show that the acousto-ultrasonic approach has the potential of being used to monitor damage and to estimate the reserve of strength of ceramic composites.

  5. Formulation and evaluation of floating matrix tablet of stavudine

    PubMed Central

    Prajapati, Pankaj H; Nakum, Vijay V; Patel, Chhagan N

    2012-01-01

    Background/Aim: The purpose of the study was to prolong the gastric residence time of stavudine by designing its floating tablets and to study the influence of different polymers on its release rate. Materials and Methods: The floating mix matrix tablets of stavudine were prepared by melt granulation method. Beeswax was used as hydrophobic meltable material. Hydroxypropyl methylcellulose (HPMC), sodium bicarbonate, and ethyl cellulose were used as matrixing agent, gas generating agent, and floating enhancer, respectively. The prepared tablets were evaluated for physicochemical parameters such as hardness, weight variation, friability, floating properties (floating lag time, total floating time), drug content, stability study, and in vitro drug release. The drug- polymer interaction was studied by Differential Scanning Calorimetry (DSC) thermal analysis and Fourier transform infared (FT-IR). Results: The floating lag time of all the formulations was within the prescribed limit (<3 min). All the formulations showed good matrix integrity and retarded the release of drug for 12 h except the formulation F5.The concentration of beeswax (X1), HPMC K4M (X2), and ethyl cellulose (X3) were selected as independent variables and drug release values at 1 (Q1), at 6 (Q6) and at 12 h (Q12) as dependent variables. Formulation F7 was selected as an optimum formulation as it showed more similarity in dissolution profile with theoretical profile (similarity factor, f2 = 70.91). The dissolution of batch F7 can be described by zero-order kinetics (R2 =0.9936) with anomalous (non-Fickian) diffusion as the release mechanism (n=0.545). There was no difference observed in release profile after temperature sensitivity study at 40°C/75% relative humidity (RH) for 1 month. Conclusion: It can be concluded from this study that the combined mix matrix system containing hydrophobic and hydrophilic polymer minimized the burst release of drug from the tablet and achieved a drug release by zero

  6. Probabilistic Evaluation of Advanced Ceramic Matrix Composite Structures

    NASA Technical Reports Server (NTRS)

    Abumeri, Galib H.; Chamis, Christos C.

    2003-01-01

    The objective of this report is to summarize the deterministic and probabilistic structural evaluation results of two structures made with advanced ceramic composites (CMC): internally pressurized tube and uniformly loaded flange. The deterministic structural evaluation includes stress, displacement, and buckling analyses. It is carried out using the finite element code MHOST, developed for the 3-D inelastic analysis of structures that are made with advanced materials. The probabilistic evaluation is performed using the integrated probabilistic assessment of composite structures computer code IPACS. The affects of uncertainties in primitive variables related to the material, fabrication process, and loadings on the material property and structural response behavior are quantified. The primitive variables considered are: thermo-mechanical properties of fiber and matrix, fiber and void volume ratios, use temperature, and pressure. The probabilistic structural analysis and probabilistic strength results are used by IPACS to perform reliability and risk evaluation of the two structures. The results will show that the sensitivity information obtained for the two composite structures from the computational simulation can be used to alter the design process to meet desired service requirements. In addition to detailed probabilistic analysis of the two structures, the following were performed specifically on the CMC tube: (1) predicted the failure load and the buckling load, (2) performed coupled non-deterministic multi-disciplinary structural analysis, and (3) demonstrated that probabilistic sensitivities can be used to select a reduced set of design variables for optimization.

  7. Nondestructive Damage Evaluation in Ceramic Matrix Composites for Aerospace Applications

    PubMed Central

    Dassios, Konstantinos G.; Kordatos, Evangelos Z.; Aggelis, Dimitrios G.; Matikas, Theodore E.

    2013-01-01

    Infrared thermography (IRT) and acoustic emission (AE) are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs) for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material's performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately. PMID:23935428

  8. Revisiting the comparison between the Shack-Hartmann and the pyramid wavefront sensors via the Fisher information matrix.

    PubMed

    Plantet, C; Meimon, S; Conan, J-M; Fusco, T

    2015-11-01

    Exoplanet direct imaging with large ground based telescopes requires eXtreme Adaptive Optics that couples high-order adaptive optics and coronagraphy. A key element of such systems is the high-order wavefront sensor. We study here several high-order wavefront sensing approaches, and more precisely compare their sensitivity to noise. Three techniques are considered: the classical Shack-Hartmann sensor, the pyramid sensor and the recently proposed LIFTed Shack-Hartmann sensor. They are compared in a unified framework based on precise diffractive models and on the Fisher information matrix, which conveys the information present in the data whatever the estimation method. The diagonal elements of the inverse of the Fisher information matrix, which we use as a figure of merit, are similar to noise propagation coefficients. With these diagonal elements, so called "Fisher coefficients", we show that the LIFTed Shack-Hartmann and pyramid sensors outperform the classical Shack-Hartmann sensor. In photon noise regime, the LIFTed Shack-Hartmann and modulated pyramid sensors obtain a similar overall noise propagation. The LIFTed Shack-Hartmann sensor however provides attractive noise properties on high orders. PMID:26561131

  9. EVALUATION OF THE EXTRACELLULAR MATRIX OF INJURED SUPRASPINATUS IN RATS

    PubMed Central

    Almeida, Luiz Henrique Oliveira; Ikemoto, Roberto; Mader, Ana Maria; Pinhal, Maria Aparecida Silva; Munhoz, Bruna; Murachovsky, Joel

    2016-01-01

    ABSTRACT Objective: To evaluate the evolution of injuries of the supraspinatus muscle by immunohistochemistry (IHC) and anatomopathological analysis in animal model (Wistar rats). Methods: Twenty-five Wistar rats were submitted to complete injury of the supraspinatus tendon, then subsequently sacrificed in groups of five animals at the following periods: immediately after the injury, 24h after the injury, 48h after, 30 days after and three months after the injury. All groups underwent histological and IHC analysis. Results: Regarding vascular proliferation and inflammatory infiltrate, we found a statistically significant difference between groups 1(control group) and 2 (24h after injury). IHC analysis showed that expression of vascular endothelial growth factor (VEGF) showed a statistically significant difference between groups 1 and 2, and collagen type 1 (Col-1) evaluation presented a statistically significant difference between groups 1 and 4. Conclusion: We observed changes in the extracellular matrix components compatible with remodeling and healing. Remodeling is more intense 24h after injury. However, VEGF and Col-1 are substantially increased at 24h and 30 days after the injury, respectively. Level of Evidence I, Experimental Study. PMID:26997907

  10. Fabrication and Preliminary Evaluation of Metal Matrix Microencapsulated Fuels

    SciTech Connect

    Terrani, Kurt A; Kiggans, Jim; Snead, Lance Lewis

    2012-01-01

    The metal matrix microencapsulated (M3) fuel concept for light water reactors (LWRs), consisting of coated fuel particles dispersed in a zirconium metal matrix, is introduced. Fabrication of M3 fuels by hot pressing, hot isostatic pressing, or extrusion methodologies has been demonstrated over the temperature range 800-1050 C. Various types of coated fuel particles with outermost layers of pyrocarbon, SiC, ZrC, and TiN have been incorporated into the zirconium metal matrix. Mechanical particle-particle and chemical particle-matrix interactions have been observed during the preliminary characterization of as-fabricated M3 specimens. Irradiation of three M3 rodlets with surrogate coated fuel particles was carried out at mean rod temperature of 400 C to 4.6 dpa in the zirconium metal matrix. Due to absence of texture in the metal matrix no irradiation growth strain (<0.09%) was detected during the post-irradiation examination.

  11. Use of R-matrix theory in light element evaluations

    SciTech Connect

    Hale, G.M.

    1992-12-31

    R-matrix theory is a general framework for describing nuclear reactions (neutron- and charged-particle-induced) that is particularly well-suited for including resonances. We will review some unconventional properties of resonances that arise from this theory, including non-Breit-Wigner (BW) resonances and shadow poles, and discuss their physical consequences. Examples will be given from the analyses of several light systems that have been used in ENDF evaluations, including {sup 4}He, {sup 5}He, {sup 15}N, and {sup 17}O. The resonances in the helium systems tend to be significantly non-BW in character, while almost all the resonances in {sup 15}N and {sup 17}O are Breit-Wigner. An interesting exception in the case of {sup 15}N indicates that some of the sub-threshold levels that have been assumed to be bound might be virtual. We find that fitting data from all possible reactions simultaneously results in level schemes for the compound systems that differ in some cases significantly from the ``accepted`` published level information.

  12. Cosmogenic 3He production rates revisited from evidences of grain size dependent release of matrix-sited helium

    USGS Publications Warehouse

    Blard, P.-H.; Pik, R.; Lave, J.; Bourles, D.; Burnard, P.G.; Yokochi, R.; Marty, B.; Trusdell, F.

    2006-01-01

    Measurements of the cosmogenic 3He (3Hec) content of various size aliquots of exposed olivines show that the fine fraction (<140 μm) has 3Hec concentrations between 14 and 100% lower than that of the coarse fractions (0.14–1 mm). Such differences attest to a grain size dependent partial release of 3Hec from the phenocrysts matrix during the preliminary in vacuo crushing. This result might have important implications since most 3Hec measurements have used for ∼20 yr a standard routine based on the fusion of bulk powdered phenocrysts, whatever their grain size. A suite of new data obtained from coarse olivine grains yielded a mean Sea Level High Latitude 3Hec production rate (SLHL P3) of 128±5 and 136±6 at. g−1 yr−1, depending on the scaling factors used. This new value, which is ∼15% higher than previously published rates, is obtained from 5 ropy flow surfaces of Mt Etna (38°N) and Hawaiian (19°N) volcanoes, at elevations between sea level and 870 m and ranging in age from 1.47±0.05 to 149±23 ka according to independent 14C or K/Ar dating. 3He loss during the crushing step might account for the discrepancy between the standard reference value of 110–115 at. g−1 y−1 and the higher SLHL P3 proposed here. More generally, removal of the powdered fraction before fusion is an important point to consider in further studies in order to avoid any 3Hec systematic underestimates.An altitudinal section has also been sampled on the ropy surface of a ∼1500 yr single flow of Mauna Loa (19°N) which allowed a new empirical atmospheric attenuation length of 149±22 g cm−2 to be documented for 3Hec in olivines between 2400 and 4000 m elevations.

  13. MATRIX PHOTOCATALYTIC, INC. PHOTOCATALYTIC OXIDATION TECHNOLOGY - INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    The Matrix Technology involves the exposure of titanium dioxide (Ti02) particles to ultraviolet light (UV). The Ti02 is activated by UV light to produce high oxidizing hydroxyl radicals. Maxtrix also uses hydrogen peroxide (H202) and ozone (03) to enhance the treatment systems p...

  14. Evaluation of a Matrix Management Approach to School Organizations.

    ERIC Educational Resources Information Center

    Gogolin, Marilyn T.; Martois, John S.

    The Management Responsibility Guidance (MRG) process is a matrix management program designed to clarify roles and improve staff integration, decision-making, effectiveness, and productivity. In 1976-77, Los Angeles County (California) used this approach in four pilot special education schools. As part of the MRG process, each staff member…

  15. SEM evaluation of nanoparticulate silver penetration into dentine collagen matrix

    NASA Astrophysics Data System (ADS)

    Bessudnova, Nadezda O.; Bilenko, David I.; Venig, Sergey B.

    2014-01-01

    In the present study a novel approach to caries management based on the application of nanoparticles of different nature to increase the mineral phase of demineralized dentin has been developed. Silver nanoparticles have been tested as a material for dentine matrix infiltration. Research findings clearly show that collagen fibers of demineralized dentine could be considered as a scaffold for mineral component delivery and the place where mineral growth can occur.

  16. Algebraic evaluation of matrix elements in the Laguerre function basis

    NASA Astrophysics Data System (ADS)

    McCoy, A. E.; Caprio, M. A.

    2016-02-01

    The Laguerre functions constitute one of the fundamental basis sets for calculations in atomic and molecular electron-structure theory, with applications in hadronic and nuclear theory as well. While similar in form to the Coulomb bound-state eigenfunctions (from the Schrödinger eigenproblem) or the Coulomb-Sturmian functions (from a related Sturm-Liouville problem), the Laguerre functions, unlike these former functions, constitute a complete, discrete, orthonormal set for square-integrable functions in three dimensions. We construct the SU(1, 1) × SO(3) dynamical algebra for the Laguerre functions and apply the ideas of factorization (or supersymmetric quantum mechanics) to derive shift operators for these functions. We use the resulting algebraic framework to derive analytic expressions for matrix elements of several basic radial operators (involving powers of the radial coordinate and radial derivative) in the Laguerre function basis. We illustrate how matrix elements for more general spherical tensor operators in three dimensional space, such as the gradient, may then be constructed from these radial matrix elements.

  17. Nondestructive Evaluation of Ceramic Matrix Composite Combustor Components

    NASA Technical Reports Server (NTRS)

    Sun, Jiangang G.; Verrilli, Michael J.; Stephan, Robert R.; Barnett, Terry R.; Ojard, Greg C.

    2003-01-01

    Combustor liners fabricated from a SiC/SiC composite (silicon carbide fibers in a silicon carbide matrix) were nondestructively interrogated before and after combustion rig testing by x-ray, ultrasonic, and thermographic techniques. In addition, mechanical test results were obtained from witness coupons, representing the as-manufactured liners, and from coupons machined from the components after combustion exposure. Thermography indications correlated with reduced material properties obtained after rig testing. The thermography indications in the SiC/SiC liners were delaminations and damaged fiber tows, as determined through microstructural examinations.

  18. Nondestructive evaluation of a ceramic matrix composite material

    NASA Technical Reports Server (NTRS)

    Grosskopf, Paul P.; Duke, John C., Jr.

    1992-01-01

    Monolithic ceramic materials have proven their usefulness in many applications, yet, their potential for critical structural applications is limited because of their sensitivity to small imperfections. To overcome this extreme sensitivity to small imperfections, ceramic matrix composite materials have been developed that have the ability to withstand some distributed damage. A borosilicate glass reinforced with several layers of silicon-carbide fiber mat has been studied. Four-point flexure and tension tests were performed not only to determine some of the material properties, but also to initiate a controlled amount of damage within each specimen. Acousto-ultrasonic (AU) measurements were performed periodically during mechanical testing. This paper will compare the AU results to the mechanical test results and data from other nondestructive methods including acoustic emission monitoring and X-ray radiography. It was found that the AU measurements were sensitive to the damage that had developed within the material.

  19. Covariance Matrix Evaluations for Independent Mass Fission Yields

    NASA Astrophysics Data System (ADS)

    Terranova, N.; Serot, O.; Archier, P.; De Saint Jean, C.; Sumini, M.

    2015-01-01

    Recent needs for more accurate fission product yields include covariance information to allow improved uncertainty estimations of the parameters used by design codes. The aim of this work is to investigate the possibility to generate more reliable and complete uncertainty information on independent mass fission yields. Mass yields covariances are estimated through a convolution between the multi-Gaussian empirical model based on Brosa's fission modes, which describe the pre-neutron mass yields, and the average prompt neutron multiplicity curve. The covariance generation task has been approached using the Bayesian generalized least squared method through the CONRAD code. Preliminary results on mass yields variance-covariance matrix will be presented and discussed from physical grounds in the case of 235U(nth, f) and 239Pu(nth, f) reactions.

  20. Covariance Matrix Evaluations for Independent Mass Fission Yields

    SciTech Connect

    Terranova, N.; Serot, O.; Archier, P.; De Saint Jean, C.

    2015-01-15

    Recent needs for more accurate fission product yields include covariance information to allow improved uncertainty estimations of the parameters used by design codes. The aim of this work is to investigate the possibility to generate more reliable and complete uncertainty information on independent mass fission yields. Mass yields covariances are estimated through a convolution between the multi-Gaussian empirical model based on Brosa's fission modes, which describe the pre-neutron mass yields, and the average prompt neutron multiplicity curve. The covariance generation task has been approached using the Bayesian generalized least squared method through the CONRAD code. Preliminary results on mass yields variance-covariance matrix will be presented and discussed from physical grounds in the case of {sup 235}U(n{sub th}, f) and {sup 239}Pu(n{sub th}, f) reactions.

  1. Formulation and evaluation of olanzapine matrix pellets for controlled release

    PubMed Central

    Vishal Gupta, N.; Balamuralidhara, V.; Mohammed Khan, S.

    2011-01-01

    Background and the purpose of the study Olanzapine is an antipsychotic used in treatment of schizophrenia. This research was carried out to design oral controlled release matrix pellets of water insoluble drug Olanzapine (OZ), using blend of Sodium Alginate (SA) and Glyceryl Palmito-Stearate (GPS) as matrix polymers, micro crystalline cellulose (MCC) as spheronizer enhancer and Sodium Lauryl Sulphate (SLS) as pore forming agent. Methods OZ formulations were developed by the pelletization technique by drug loaded pellets and characterized with regard to the drug content, size distribution, Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction study (XRD). Stability studies were carried out on the optimized formulation for a period of 90 days at 40±2 °C and 75±5% relative humidity. Results and major conclusion The drug content was in the range of 93.34–98.12%. The mean particle size of the drug loaded pellets was in the range 1024 to 1087µm. SEM photographs and calculated sphericity factor confirmed that the prepared formulations were spherical in nature. The compatibility between drug and polymers in the drug loaded pellets was confirmed by DSC and FTIR studies. Stability studies indicated that pellets are stable. XRD patterns revealed the crystalline nature of the pure OZ. Loose surface crystal study indicated that crystalline OZ is present in all formulations and more clear in formulation F5. Drug release was controlled for more than 24 hrs and mechanism of the drug release followed by Fickian diffusion. It may be concluded that F5 is an ideal formulation for once a day administration. PMID:22615665

  2. Development and evaluation of hydrophilic colloid matrix of famotidine tablets.

    PubMed

    Shoaib, Muhammad Harris; Al Sabah Siddiqi, Saniah; Yousuf, Rabia Ismail; Zaheer, Kamran; Hanif, Muhammad; Rehana, Saeed; Jabeen, Sabahat

    2010-06-01

    The objective of the present study was to develop a once-daily sustained-release (SR) matrix tablet of famotidine. Nine different formulations (F1-F9) were prepared by direct compression method using Avicel PH101 as filler/binder in the range of 41-27% in F1-F3, 18-22% in F4-F7, and 16-18% in F8-F9 and hydroxypropyl methylcellulose (4,000 cps) as hydrophilic matrix was used in F1-F3 from 19% to 30%, around 40% in F4-F7, and 42-45% in F8-F9. Talc and Aerosil were added in the ratio of 0.7-1.2%. The tablets were subjected to various physical parameters including weight variation test, hardness, thickness, diameter, friability, and in vitro release studies. Assay was also performed according to the USP 30 NF 25 procedure. The results of the physical parameters and assay were found to be within the acceptable range. In vitro dissolution results indicated that formulation F4-F7, having around 40% of rate control polymer, produced a SR pattern throughout 24 h. F1-F3 showed drug release at a faster rate, while F8-F9 released much slower, i.e., <80% in 24 h. Model-dependent and model-independent methods were used for data analysis and the best results were observed for F4 in zero order (r(2) = 0.984) and F6 in Korsmeyer and Higuchi (r(2) = 0.992 and 0.988). The parameter n indicated anomalous diffusion, while beta in Weibull showed a parabolic curve with higher initial slope. The f(2) similarity test was performed taking F4 as a reference formulation. Only the F5-F7 formulations were similar to the reference formulation F4. The mean dissolution time was around 10 h for the successful formulation. PMID:20422332

  3. Evaluative Priming of Naming and Semantic Categorization Responses Revisited: A Mutual Facilitation Explanation

    ERIC Educational Resources Information Center

    Schmitz, Melanie; Wentura, Dirk

    2012-01-01

    The evaluative priming effect (i.e., faster target responses following evaluatively congruent compared with evaluatively incongruent primes) in nonevaluative priming tasks (such as naming or semantic categorization tasks) is considered important for the question of how evaluative connotations are represented in memory. However, the empirical…

  4. Nondestructive evaluation of ceramic and metal matrix composites for NASA's HITEMP and enabling propulsion materials programs

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    1992-01-01

    In a preliminary study, ultrasonic, x-ray opaque, and fluorescent dye penetrants techniques were used to evaluate and characterize ceramic and metal matrix composites. Techniques are highlighted for identifying porosity, fiber alignment, fiber uniformity, matrix cracks, fiber fractures, unbonds or disbonds between laminae, and fiber-to-matrix bond variations. The nondestructive evaluations (NDE) were performed during processing and after thermomechanical testing. Specific examples are given for Si3N4/SiC (SCS-6 fiber), FeCrAlY/Al2O3 fibers, Ti-15-3/SiC (SCS-6 fiber) materials, and Si3N4/SiC (SCS-6 fiber) actively cooled panel components. Results of this study indicate that the choice of the NDE tools to be used can be optimized to yield a faithful and accurate evaluation of advanced composites.

  5. Characterization and Damage Evaluation of Coal Tar Pitch Carbon Matrix Used in Carbon/Carbon Composites

    NASA Astrophysics Data System (ADS)

    Bhagat, Atul Ramesh; Mahajan, Puneet

    2016-07-01

    Flexure, compressive, and shear properties of the carbon matrix in carbon/carbon (C/C) composites made via a pitch impregnation method have been determined. The pitch carbon matrix was made using the same densification cycle used in making the C/C composite. Cyclic compression tests were performed on the matrix specimens. While unloading, a reduction in modulus was observed and residual strains were observed on complete unloading. These features were attributed to the presence of damage and plasticity in the densified matrix. A J 2 plasticity model with damage was used to simulate this behavior numerically. The parameters required for plasticity and damage model were evaluated iteratively by comparing the results in experiments with simulation.

  6. Porcine incisional hernia model: Evaluation of biologically derived intact extracellular matrix repairs

    PubMed Central

    Delossantos, Aubrey I; Rodriguez, Neil L; Patel, Paarun; Franz, Michael G; Wagner, Christopher T

    2013-01-01

    We compared fascial wounds repaired with non-cross-linked intact porcine-derived acellular dermal matrix versus primary closure in a large-animal hernia model. Incisional hernias were created in Yucatan pigs and repaired after 3 weeks via open technique with suture-only primary closure or intraperitoneally placed porcine-derived acellular dermal matrix. Progressive changes in mechanical and biological properties of porcine-derived acellular dermal matrix and repair sites were assessed. Porcine-derived acellular dermal matrix–repaired hernias of additional animals were evaluated 2 and 4 weeks post incision to assess porcine-derived acellular dermal matrix regenerative potential and biomechanical changes. Hernias repaired with primary closure showed substantially more scarring and bone hyperplasia along the incision line. Mechanical remodeling of porcine-derived acellular dermal matrix was noted over time. Porcine-derived acellular dermal matrix elastic modulus and ultimate tensile stress were similar to fascia at 6 weeks. The biology of porcine-derived acellular dermal matrix–reinforced animals was more similar to native abdominal wall versus that with primary closure. In this study, porcine-derived acellular dermal matrix–reinforced repairs provided more complete wound healing response compared with primary closure. PMID:24555008

  7. The Components of Smile Design: New York University Smile Evaluation Form Revisited, Update 2015.

    PubMed

    Calamia, John R; Wolff, Mark S

    2015-07-01

    This article updates a simple checklist of foundational knowledge in aesthetic dental concepts that allows clinicians to organize their thoughts, to record the concerns of the patient, and to map out those improvements that must be addressed. This adjunct is called a Smile Evaluation Form. Along with other adjuncts such as radiographs, study casts, and diagnostic wax-ups, the Smile Evaluation Form allows clinicians to form a conceptual visualization of the expected end point. It provides a checklist for discussions with other disciplines in the team, to provide a logical sequence of treatment with a mutually agreed-on end point. PMID:26140962

  8. Revisiting the AAUP Recommendation: The Viability of Collegiality as a Fourth Criterion for University Faculty Evaluation

    ERIC Educational Resources Information Center

    Johnston, Pattie C.; Schimmel, Tammy; O'Hara, Hunter

    2012-01-01

    Legal rulings have called for the inclusion of collegiality as a fourth evaluation category for university faculty. Collegiality is considered to be any extra-role behavior that represents individuals' behavior that is discretionary, not recognized by the formal reward system and that, in the aggregate, promotes the effective functioning of the…

  9. On Information Retrieval (IR) Systems: Revisiting Their Development, Evaluation Methodologies, and Assumptions (SIGs LAN, ED).

    ERIC Educational Resources Information Center

    Stirling, Keith

    2000-01-01

    Describes a session on information retrieval systems that planned to discuss relevance measures with Web-based information retrieval; retrieval system performance and evaluation; probabilistic independence of index terms; vector-based models; metalanguages and digital objects; how users assess the reliability, timeliness and bias of information;…

  10. Reflections on Post-Evaluation of Baccalaureate Programs: Revisiting Education Quality

    ERIC Educational Resources Information Center

    Jianrong, Sun

    2009-01-01

    This paper discusses the distinction between two types of educational quality: quality at the institutional level and quality at the student learning level. The key element for continuous institutional improvement after completion of the evaluation of institutional teaching should be on redefining quality in student learning and developing a…

  11. Counterfactual Evaluation of Outcomes in Social Risk Decision-Making Situations: The Cognitive Developmental Paradox Revisited

    PubMed Central

    Padrón, Iván; Rodrigo, María Jose; de Vega, Manuel

    2016-01-01

    We report a study that examined the existence of a cognitive developmental paradox in the counterfactual evaluation of decision-making outcomes. According to this paradox adolescents and young adults could be able to apply counterfactual reasoning and, yet, their counterfactual evaluation of outcomes could be biased in a salient socio-emotional context. To this aim, we analyzed the impact of health and social feedback on the counterfactual evaluation of outcomes in a laboratory decision-making task involving short narratives with the presence of peers. Forty risky (e.g., taking or refusing a drug), forty neutral decisions (e.g., eating a hamburger or a hotdog), and emotions felt following positive or negative outcomes were examined in 256 early, mid- and late adolescents, and young adults, evenly distributed. Results showed that emotional ratings to negative outcomes (regret and disappointment) but not to positive outcomes (relief and elation) were attenuated when feedback was provided. Evidence of development of cognitive decision-making capacities did also exist, as the capacity to perform faster emotional ratings and to differentially allocate more resources to the elaboration of emotional ratings when no feedback information was available increased with age. Overall, we interpret these findings as challenging the traditional cognitive developmental assumption that development necessarily proceeds from lesser to greater capacities, reflecting the impact of socio-emotional processes that could bias the counterfactual evaluation of social decision-making outcomes. PMID:27152127

  12. Generalization versus contextualization in automatic evaluation revisited: A meta-analysis of successful and failed replications.

    PubMed

    Gawronski, Bertram; Hu, Xiaoqing; Rydell, Robert J; Vervliet, Bram; De Houwer, Jan

    2015-08-01

    To account for disparate findings in the literature on automatic evaluation, Gawronski, Rydell, Vervliet, and De Houwer (2010) proposed a representational theory that specifies the contextual conditions under which automatic evaluations reflect initially acquired attitudinal information or subsequently acquired counterattitudinal information. The theory predicts that automatic evaluations should reflect the valence of expectancy-violating counterattitudinal information only in the context in which this information had been learned. In contrast, automatic evaluations should reflect the valence of initial attitudinal information in any other context, be it the context in which the initial attitudinal information had been acquired (ABA renewal) or a novel context in which the target object had not been encountered before (ABC renewal). The current article presents a meta-analysis of all published and unpublished studies from the authors' research groups regardless of whether they produced the predicted pattern of results. Results revealed average effect sizes of d = 0.249 for ABA renewal (30 studies, N = 3,142) and d = 0.174 for ABC renewal (27 studies, N = 2,930), both of which were significantly different from zero. Effect sizes were moderated by attention to context during learning, order of positive and negative information, context-valence contingencies during learning, and sample country. Although some of the obtained moderator effects are consistent with the representational theory, others require theoretical refinements and future research to gain deeper insights into the mechanisms underlying contextual renewal. PMID:26010481

  13. NAEP Reading Revisit: An Evaluation of the 1992 Achievement Levels Descriptions.

    ERIC Educational Resources Information Center

    American Coll. Testing Program, Iowa City, IA.

    A study was designed to provide recommendations regarding the use of the achievement levels set in 1992 for reporting National Assessment of Educational Progress (NAEP) reading results in 1994 and in future NAEP reading assessments. Two procedures were used: the Item Difficulty Categorization (IDC) procedure involved an evaluation of the…

  14. Counterfactual Evaluation of Outcomes in Social Risk Decision-Making Situations: The Cognitive Developmental Paradox Revisited.

    PubMed

    Padrón, Iván; Rodrigo, María Jose; de Vega, Manuel

    2016-01-01

    We report a study that examined the existence of a cognitive developmental paradox in the counterfactual evaluation of decision-making outcomes. According to this paradox adolescents and young adults could be able to apply counterfactual reasoning and, yet, their counterfactual evaluation of outcomes could be biased in a salient socio-emotional context. To this aim, we analyzed the impact of health and social feedback on the counterfactual evaluation of outcomes in a laboratory decision-making task involving short narratives with the presence of peers. Forty risky (e.g., taking or refusing a drug), forty neutral decisions (e.g., eating a hamburger or a hotdog), and emotions felt following positive or negative outcomes were examined in 256 early, mid- and late adolescents, and young adults, evenly distributed. Results showed that emotional ratings to negative outcomes (regret and disappointment) but not to positive outcomes (relief and elation) were attenuated when feedback was provided. Evidence of development of cognitive decision-making capacities did also exist, as the capacity to perform faster emotional ratings and to differentially allocate more resources to the elaboration of emotional ratings when no feedback information was available increased with age. Overall, we interpret these findings as challenging the traditional cognitive developmental assumption that development necessarily proceeds from lesser to greater capacities, reflecting the impact of socio-emotional processes that could bias the counterfactual evaluation of social decision-making outcomes. PMID:27152127

  15. Revisiting "What Works for Whom?": A Qualitative Framework for Evaluating Clinical Effectiveness in Child Psychotherapy

    ERIC Educational Resources Information Center

    Urwin, Cathy

    2007-01-01

    This paper describes a framework for evaluating the effectiveness of child psychotherapy used by child psychotherapists in an inner city Child and Adolescent Mental Health Service (CAMHS). The Hopes and Expectations for Treatment Approach (HETA) involves using the assessment for psychotherapy that normally precedes treatment to derive a baseline…

  16. Controlled release evaluation of bacterial fertilizer using polymer composites as matrix.

    PubMed

    Wu, Chin-San

    2008-11-24

    The use of polybutylene succinate (PBSU)/starch-type composite as biodegradable matrix material for the controlled release of bacterial fertilizer was evaluated. The composites were prepared by a melting-blending method and various methods/instruments were applied to characterize composites and PBSU. The mechanical properties of the PBSU/starch composite were worse than PBSU alone because the former had poor compatibility between starch and the polymer matrix. Much better dispersion and homogeneity were observed in the composite when PBSU was replaced by acrylic acid grafted PBSU (PBSU-g-AA), hence leading to better mechanical properties of PBSU-g-AA/starch. Furthermore, PBSU-g-AA/starch was more easily processed. The bacterial fertilizer was encapsulated in PBSU and PBSU-g-AA/starch matrix. Increased blending of starch increased the biodegradability of matrix and the amount and rate of cell release from matrix suggesting that this composite is a promising candidate material for 'controlled release' bacterial fertilizer. PMID:18796320

  17. Combinatorial theory of the semiclassical evaluation of transport moments. I. Equivalence with the random matrix approach

    SciTech Connect

    Berkolaiko, G.; Kuipers, J.

    2013-11-15

    To study electronic transport through chaotic quantum dots, there are two main theoretical approaches. One involves substituting the quantum system with a random scattering matrix and performing appropriate ensemble averaging. The other treats the transport in the semiclassical approximation and studies correlations among sets of classical trajectories. There are established evaluation procedures within the semiclassical evaluation that, for several linear and nonlinear transport moments to which they were applied, have always resulted in the agreement with random matrix predictions. We prove that this agreement is universal: any semiclassical evaluation within the accepted procedures is equivalent to the evaluation within random matrix theory. The equivalence is shown by developing a combinatorial interpretation of the trajectory sets as ribbon graphs (maps) with certain properties and exhibiting systematic cancellations among their contributions. Remaining trajectory sets can be identified with primitive (palindromic) factorisations whose number gives the coefficients in the corresponding expansion of the moments of random matrices. The equivalence is proved for systems with and without time reversal symmetry.

  18. Route guidance strategies revisited: Comparison and evaluation in an asymmetric two-route traffic network

    NASA Astrophysics Data System (ADS)

    He, Zhengbing; Chen, Bokui; Jia, Ning; Guan, Wei; Lin, Benchuan; Wang, Binghong

    2014-12-01

    To alleviate traffic congestion, a variety of route guidance strategies have been proposed for intelligent transportation systems. A number of strategies are introduced and investigated on a symmetric two-route traffic network over the past decade. To evaluate the strategies in a more general scenario, this paper conducts eight prevalent strategies on an asymmetric two-route traffic network with different slowdown behaviors on alternative routes. The results show that only mean velocity feedback strategy (MVFS) is able to equalize travel time, i.e. approximate user optimality (UO); while the others fail due to incapability of establishing relations between the feedback parameters and travel time. The paper helps better understand these strategies, and suggests MVFS if the authority intends to achieve user optimality.

  19. Evaluation of microwave digestion systems for mercury recovery in an oil matrix

    SciTech Connect

    Whitaker, M.J.; Clymire, J.W.

    1997-09-01

    The scope of this document is to characterize three microwave systems developed by CEM Corporation. The purpose of this investigative work was to evaluate the performance of each system for dissolution qualities and the recovery of mercury in an oil based matrix. The microwave systems evaluated were the heavy duty vessel system (HDV), the advanced composite system (ACV), and the open vessel system (OVS). All three systems have automated features, but all systems are limited by one factor or another. EPA method 3051 was the procedure used for sample preparation for this project. This particular microwave digestion method can also be used for other metal analytes of interest. Of the three different systems, only the HDV (now UDV) demonstrated complete digestion of the oil based matrix in a one step process and acceptable mercury recoveries.

  20. The warfarin–cranberry juice interaction revisited: A systematic in vitro–in vivo evaluation

    PubMed Central

    Ngo, Ngoc; Brantley, Scott J; Carrizosa, Daniel R; Kashuba, Angela DM; Dees, E Claire; Kroll, David J; Oberlies, Nicholas H; Paine, Mary F

    2010-01-01

    Background Cranberry products have been implicated in several case reports to enhance the anticoagulant effect of warfarin. The mechanism could involve inhibition of the hepatic CYP2C9-mediated metabolic clearance of warfarin by components in cranberry. Because dietary/natural substances vary substantially in bioactive ingredient composition, multiple cranberry products were evaluated in vitro before testing this hypothesis in vivo. Methods The inhibitory effects of five types of cranberry juices were compared with those of water on CYP2C9 activity (S-warfarin 7-hydroxylation) in human liver microsomes (HLM). The most potent juice was compared with water on S/R-warfarin pharmacokinetics in 16 healthy participants given a single dose of warfarin 10 mg. Results Only one juice inhibited S-warfarin 7-hydroxylation in HLM in a concentration-dependent manner (P < 0.05), from 20% to >95% at 0.05% to 0.5% juice (v/v), respectively. However, this juice had no effect on the geometric mean AUC0–∞ and terminal half-life of S/R-warfarin in human subjects. Conclusions A cranberry juice that inhibited warfarin metabolism in HLM had no effect on warfarin clearance in healthy participants. The lack of an in vitro–in vivo concordance likely reflects the fact that the site of warfarin metabolism (liver) is remote from the site of exposure to the inhibitory components in the cranberry juice (intestine). PMID:20865058

  1. A theoretical rut: revisiting and critically evaluating the generalized under/over-connectivity hypothesis of autism.

    PubMed

    Picci, Giorgia; Gotts, Stephen J; Scherf, K Suzanne

    2016-07-01

    In 2004, two papers proposed that pervasive functional under-connectivity (Just et al., ) or a trade-off between excessive local connectivity at the cost of distal under-connectivity (Belmonte et al., ) characterizes atypical brain organization in autism. Here, we take stock of the most recent and rigorous functional and structural connectivity findings with a careful eye toward evaluating the extent to which they support these original hypotheses. Indeed, the empirical data do not support them. From rsfMRI studies in adolescents and adults, there is an emerging consensus regarding long-range functional connections indicating cortico-cortical under-connectivity, specifically involving the temporal lobes, combined with subcortical-cortical over-connectivity. In contrast, there is little to no consensus regarding local functional connectivity or findings from task-based functional connectivity studies. The structural connectivity data suggest that white matter tracts are pervasively weak, particularly in the temporal lobe. Together, these findings are revealing how deeply complex the story is regarding atypical neural network organization in autism. In other words, distance and strength of connectivity as individual factors or as interacting factors do not consistently explain the patterns of atypical neural connectivity in autism. Therefore, we make several methodological recommendations and highlight developmental considerations that will help researchers in the field cultivate new hypotheses about the nature and mechanisms of potentially aberrant functional and structural connectivity in autism. PMID:27412228

  2. Holland in Iceland revisited: an emic approach to evaluating U.S. vocational interest models.

    PubMed

    Einarsdóttir, Sif; Rounds, James; Su, Rong

    2010-07-01

    An emic approach was used to test the structural validity and applicability of Holland's (1997) RIASEC (Realistic, Investigative, Artistic, Social, Enterprising, Conventional) model in Iceland. Archival data from the development of the Icelandic Interest Inventory (Einarsdóttir & Rounds, 2007) were used in the present investigation. The data included an indigenous pool of occupations and work-task items representing Iceland's world of work that had been administered to a sample of 597 upper secondary school students. Multidimensional scaling analysis and property vector fitting using Prediger's (1981) work-task dimensions were applied to the item responses to test if the RIASEC model could be identified. The results indicated that a 4-dimensional solution better explains the interest space in Iceland than Holland's 2-dimensional RIASEC representation. The work-task dimension of People-Things and the Sex-Type and Prestige dimensions were located in the 1st and 2nd dimensions of the multidimensional scaling solution, but Data-Ideas, a dimension critical to the RIASEC model, was not. The 3rd and 4th dimensions did not correspond to any dimensions previously detected in structural studies in the United States and seem to be related to specific ecological, cultural, and political forces in Iceland. These results demonstrate the importance of selecting representative indigenous occupations and work tasks when evaluating the RIASEC model. The present study is an example of the next step in a comprehensive cross-cultural research program on vocational interests, an emic investigation. PMID:21133585

  3. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SERVICES (CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES General... be subject to user fees unless otherwise exempted. Revisit survey means a survey performed with..., or substantiated complaint survey and that is designed to evaluate the extent to which...

  4. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SERVICES (CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES General... be subject to user fees unless otherwise exempted. Revisit survey means a survey performed with..., or substantiated complaint survey and that is designed to evaluate the extent to which...

  5. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SERVICES (CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES General... be subject to user fees unless otherwise exempted. Revisit survey means a survey performed with..., or substantiated complaint survey and that is designed to evaluate the extent to which...

  6. Evaluation of matrix effects in analysis of estrogen using liquid chromatography-tandem mass spectrometry.

    PubMed

    Nguyen, Hien P; Li, Li; Nethrapalli, Imam S; Guo, Ningning; Toran-Allerand, C Dominique; Harrison, David E; Astle, C Michael; Schug, Kevin A

    2011-08-01

    Matrix effects of different biological samples, including phosphate-buffered saline-bovine serum albumin (PBS-BSA), gelded horse serum, mouse serum, and mouse brain, were investigated for the determination of 17α- and β-estradiol using derivatization with dansyl chloride prior to LC-MS/MS. Matrix effects were evaluated based on the slopes of regression lines plotted from results obtained in biological matrices versus pure standard solutions. Such plots indicate the enhancement or suppression of signal based on the presence of a particular biological fluid for a particular method. The matrix effects from PBS-BSA were similar to those of mouse serum. In contrast, analyses performed from horse serum and mouse brain yielded significant ion suppression, especially for 17β-estradiol. Precipitation during derivatization was observed when pre-concentrated samples were processed with ethyl acetate as an extraction solvent. This was overcome with the use of methyl tert-butyl ether; however, matrix effects from this preparation were still present, evidenced by signal suppression and poor linearity in the standard curve. This work affirms that caution should be taken in the transfer of methods for use with different biological matrices, especially in the case where surrogate matrices are necessary for calibration purposes. PMID:21721122

  7. Application of Boston matrix combined with SWOT analysis on operational development and evaluations of hospital development.

    PubMed

    Tao, Z-Q; Shi, A-M

    2016-05-01

    The aim of this study is to explore the application of Boston matrix combined with SWOT analysis on operational development and evaluations of hospital departments. We selected 73 clinical and medical technology departments of our hospital from 2011 to 2013, and evaluated our hospital by Boston matrix combined with SWOT analysis according to the volume of services, medical quality, work efficiency, patients' evaluations, development capacity, operational capability, economic benefits, comprehensive evaluation of hospital achievement, innovation ability of hospital, influence of hospital, human resources of hospital, health insurance costs, etc. It was found that among clinical departments, there were 11 in Stars (22.4%), 17 in cash cow (34.7%), 15 in question marks (31.2%), 6 Dogs (12.2%), 16 in the youth stage of life cycle assessment (27.6%), 14 in the prime stage (24.1%), 12 in the stationary stage (20.7%), 9 in the aristocracy stage (15.5%) and 7 in the recession stage (12.1%). Among medical technology departments, there were 5 in Stars (20.8%), 1 in Cash cow (4.2%), 10 in question marks (41.6%), 8 Dogs (29.1%), 9 in the youth stage of life cycle assessment (37.5%), 4 in the prime stage (16.7%), 4 in the stable stage (16.7%), 1 in the aristocracy stage (4.2%) and 6 in the recession stage (25%). In conclusion, Boston matrix combined with SWOT analysis is suitable for operational development and comprehensive evaluations of hospital development, and it plays an important role in providing hospitals with development strategies. PMID:27249614

  8. Assessment of Geophysical Techniques Application during CTBTO On-Site inspections using the Evaluation Matrix concept

    NASA Astrophysics Data System (ADS)

    Gaya-Piqué, Luis R.; Stefanova, Stefka; Hawkins, Ward L.; Sweeney, Jerry J.; Melamud, Mordechai; Prah, Matjaz

    2010-05-01

    Application of geophysical methods to collect evidence of possible conduct of an underground nuclear explosion is an essential element of the on-site inspection (OSI) verification component of the Comprehensive Nuclear Test Ban Treaty (CTBT). As with any geophysical survey, effective use of resources during an OSI is essential. The evaluation matrix approach can be applied to both assess in a comprehensive manner the suitability of OSI techniques with respect to an ensemble of different conditions based on a specific OSI scenario (Technology Evaluation Matrix, TEM) and to estimate the technical readiness status of a specific technology (Technical Readiness Status Matrix, TRSM). Applied to the work of the OSI Division of the Provisional Secretariat of the Comprehensive Nuclear-Test Ban Treaty Organization (CTBTO), the TRSM will support policy planning and operational projects that need to be thoroughly analyzed, providing a flexible mechanism that allows for fast and rationale decision making for resource allocation; on the other hand, the TEM will improve the functionality of an OSI by providing the inspection team a reference tool for a particular OSI scenario (e.g., yield and depth of the triggering event, geology of the inspection area, possible emplacement conditions). This assessment is important because of the limited time and number of team members provided to the inspection team for the conduct of an inspection. In this work we discuss the application of the TEM concept to the set of geophysical techniques that can be applied during an OSI for two basic underground nuclear explosion (UNE) scenarios: explosions conducted in a vertical emplacement (i.e. borehole) and explosions conducted in a horizontal emplacement (i.e. tunnel). After introducing the natural and manmade signatures usually associated with an UNE and the geophysical techniques allowed by the Treaty (with imposed constraints), examples of evaluation matrices are given for each scenario. The

  9. Laboratory Experiments to Evaluate Diffusion of 14C into Nevada Test Site Carbonate Aquifer Matrix

    SciTech Connect

    Ronald L. Hershey; William Howcroft; Paul W. Reimus

    2003-03-01

    Determination of groundwater flow velocities at the Nevada Test Site is important since groundwater is the principal transport medium of underground radionuclides. However, 14C-based groundwater velocities in the carbonate aquifers of the Nevada Test Site are several orders of magnitude slower than velocities derived from the Underground Test Area regional numerical model. This discrepancy has been attributed to the loss or retardation of 14C from groundwater into the surrounding aquifer matrix making 14C-based groundwater ages appear much older. Laboratory experiments were used to investigate the retardation of 14C in the carbonate aquifers at the Nevada Test Site. Three sets of experiments were conducted evaluating the diffusion of 14C into the carbonate aquifer matrix, adsorption and/or isotopic exchange onto the pore surfaces of the carbonate matrix, and adsorption and/or isotopic exchange onto the fracture surfaces of the carbonate aquifer. Experimental results a nd published aquifer matrix and fracture porosities from the Lower Carbonate Aquifer were applied to a 14C retardation model. The model produced an extremely wide range of retardation factors because of the wide range of published aquifer matrix and fracture porosities (over three orders of magnitude). Large retardation factors suggest that groundwater with very little measured 14C activity may actually be very young if matrix porosity is large relative to the fracture porosity. Groundwater samples collected from highly fractured aquifers with large effective fracture porosities may have relatively small correction factors, while samples from aquifers with a few widely spaced fractures may have very large correction factors. These retardation factors were then used to calculate groundwater velocities from a proposed flow path at the Nevada Test Site. The upper end of the range of 14C correction factors estimated groundwater velocities that appear to be at least an order of magnitude too high compared

  10. Evaluation of the swelling behaviour of iota-carrageenan in monolithic matrix tablets.

    PubMed

    Kelemen, András; Buchholcz, Gyula; Sovány, Tamás; Pintye-Hódi, Klára

    2015-08-10

    The swelling properties of monolithic matrix tablets containing iota-carrageenan were studied at different pH values, with measurements of the swelling force and characterization of the profile of the swelling curve. The swelling force meter was linked to a PC by an RS232 cable and the measured data were evaluated with self-developed software. The monitor displayed the swelling force vs. time curve with the important parameters, which could be fitted with an Analysis menu. In the case of iota-carrageenan matrix tablets, it was concluded that the pH and the pressure did not influence the swelling process, and the first section of the swelling curve could be fitted by the Korsmeyer-Peppas equation. PMID:25966465

  11. Evaluation of tensile strength of hybrid fiber (jute/gongura) reinforced hybrid polymer matrix composites

    NASA Astrophysics Data System (ADS)

    Venkatachalam, G.; Gautham Shankar, A.; Vijay, Kumar V.; Chandan, Byral R.; Prabaharan, G. P.; Raghav, Dasarath

    2015-07-01

    The polymer matrix composites attract many industrial applications due to its light weight, less cost and easy for manufacturing. In this paper, an attempt is made to prepare and study of the tensile strength of hybrid (two natural) fibers reinforced hybrid (Natural + Synthetic) polymer matrix composites. The samples were prepared with hybrid reinforcement consists of two different fibers such as jute and Gongura and hybrid polymer consists of polyester and cashew nut shell resins. The hybrid composites tensile strength is evaluated to study the influence of various fiber parameters on mechanical strength. The parameters considered here are the duration of fiber treatment, the concentration of alkali in fiber treatment and nature of fiber content in the composites.

  12. Standard test evaluation of graphite fiber/resin matrix composite materials for improved toughness

    NASA Technical Reports Server (NTRS)

    Chapman, Andrew J.

    1984-01-01

    Programs sponsored by NASA with the commercial transport manufacturers to develop a technology data base are required to design and build composite wing and fuselage structures. To realize the full potential of composite structures in these strength critical designs, material systems having improved ductility and interlaminar toughness are being sought. To promote systematic evaluation of new materials, NASA and the commercial transport manufacturers have selected and standardized a set of five common tests. These tests evaluate open hole tension and compression performance, compression performance after impact at an energy level of 20 ft-lb, and resistance to delamination. Ten toughened resin matrix/graphite fiber composites were evaluated using this series of tests, and their performance is compared with a widely used composite system.

  13. Evaluation of Solid Modeling Software for Finite Element Analysis of Woven Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Mital, Subodh; Lang, Jerry

    2010-01-01

    Three computer programs, used for the purpose of generating 3-D finite element models of the Repeating Unit Cell (RUC) of a textile, were examined for suitability to model woven Ceramic Matrix Composites (CMCs). The programs evaluated were the open-source available TexGen, the commercially available WiseTex, and the proprietary Composite Material Evaluator (COMATE). A five-harness-satin (5HS) weave for a melt-infiltrated (MI) silicon carbide matrix and silicon carbide fiber was selected as an example problem and the programs were tested for their ability to generate a finite element model of the RUC. The programs were also evaluated for ease-of-use and capability, particularly for the capability to introduce various defect types such as porosity, ply shifting, and nesting of a laminate. Overall, it was found that TexGen and WiseTex were useful for generating solid models of the tow geometry; however, there was a lack of consistency in generating well-conditioned finite element meshes of the tows and matrix. TexGen and WiseTex were both capable of allowing collective and individual shifting of tows within a ply and WiseTex also had a ply nesting capability. TexGen and WiseTex were sufficiently userfriendly and both included a Graphical User Interface (GUI). COMATE was satisfactory in generating a 5HS finite element mesh of an idealized weave geometry but COMATE lacked a GUI and was limited to only 5HS and 8HS weaves compared to the larger amount of weave selections available with TexGen and WiseTex.

  14. Formulation and Evaluation of Cefixime Trihydrate Matrix Tablets Using HPMC, Sodium CMC, Ethyl Cellulose.

    PubMed

    Sirisolla, Janakidevi; Ramanamurthy, K V

    2015-01-01

    The objective of the present work is to design sustained release matrix tablets of cefixime trihydrate by incorporating drug in a matrix made up of release retardant polymers, which prolong drug release leading to minimization of the peak and valley effect in the plasma and provide patient convenience. The effect of combination of polymers on parameters like release pattern, release mechanism of the drug were studied. Total nine formulations each containing 200 mg of drug were prepared by direct compression method. The formulations F-1, F-2, F-3 were prepared with a 1:1 drug to polymer ratio using hydroxypropyl methylcellulose, carboxymethyl cellulose sodium and ethyl cellulose. F-4 was prepared with a 1:1 ratio of hydroxypropyl methylcellulose, carboxymethyl cellulose sodium, F-5 as prepared with a 1:1 ratio of hydroxypropyl methylcellulose and ethyl cellulose, F-6 was prepared with a 1:1 ratio of carboxymethyl cellulose sodium and ethyl cellulose, F-7, F-8, F-9 were prepared by using polymers hydroxypropyl methylcellulose, carboxymethyl cellulose sodium and ethyl cellulose in the ratios of 0.5:0.5:1, 0.5:1:0.5, and 1:0.5:0.5. Designed matrix tablets were evaluated for various pre-compression and post-compression parameters. Formulation F-5 showed 102.15 % release at the end of 12 h and it is selected as the best formulation. All Formulations followed zero order with non-Fickian diffusion method. PMID:26180278

  15. Formulation and Evaluation of Cefixime Trihydrate Matrix Tablets Using HPMC, Sodium CMC, Ethyl Cellulose

    PubMed Central

    Sirisolla, Janakidevi; Ramanamurthy, K. V.

    2015-01-01

    The objective of the present work is to design sustained release matrix tablets of cefixime trihydrate by incorporating drug in a matrix made up of release retardant polymers, which prolong drug release leading to minimization of the peak and valley effect in the plasma and provide patient convenience. The effect of combination of polymers on parameters like release pattern, release mechanism of the drug were studied. Total nine formulations each containing 200 mg of drug were prepared by direct compression method. The formulations F-1, F-2, F-3 were prepared with a 1:1 drug to polymer ratio using hydroxypropyl methylcellulose, carboxymethyl cellulose sodium and ethyl cellulose. F-4 was prepared with a 1:1 ratio of hydroxypropyl methylcellulose, carboxymethyl cellulose sodium, F-5 as prepared with a 1:1 ratio of hydroxypropyl methylcellulose and ethyl cellulose, F-6 was prepared with a 1:1 ratio of carboxymethyl cellulose sodium and ethyl cellulose, F-7, F-8, F-9 were prepared by using polymers hydroxypropyl methylcellulose, carboxymethyl cellulose sodium and ethyl cellulose in the ratios of 0.5:0.5:1, 0.5:1:0.5, and 1:0.5:0.5. Designed matrix tablets were evaluated for various pre-compression and post-compression parameters. Formulation F-5 showed 102.15 % release at the end of 12 h and it is selected as the best formulation. All Formulations followed zero order with non-Fickian diffusion method. PMID:26180278

  16. Evaluation of a Variable-Impedance Ceramic Matrix Composite Acoustic Liner

    NASA Technical Reports Server (NTRS)

    Jones, M. G.; Watson, W. R.; Nark, D. M.; Howerton, B. M.

    2014-01-01

    As a result of significant progress in the reduction of fan and jet noise, there is growing concern regarding core noise. One method for achieving core noise reduction is via the use of acoustic liners. However, these liners must be constructed with materials suitable for high temperature environments and should be designed for optimum absorption of the broadband core noise spectrum. This paper presents results of tests conducted in the NASA Langley Liner Technology Facility to evaluate a variable-impedance ceramic matrix composite acoustic liner that offers the potential to achieve each of these goals. One concern is the porosity of the ceramic matrix composite material, and whether this might affect the predictability of liners constructed with this material. Comparisons between two variable-depth liners, one constructed with ceramic matrix composite material and the other constructed via stereolithography, are used to demonstrate this material porosity is not a concern. Also, some interesting observations are noted regarding the orientation of variable-depth liners. Finally, two propagation codes are validated via comparisons of predicted and measured acoustic pressure profiles for a variable-depth liner.

  17. Method and apparatus for evaluating structural weakness in polymer matrix composites

    DOEpatents

    Wachter, E.A.; Fisher, W.G.

    1996-01-09

    A method and apparatus for evaluating structural weaknesses in polymer matrix composites is described. An object to be studied is illuminated with laser radiation and fluorescence emanating therefrom is collected and filtered. The fluorescence is then imaged and the image is studied to determine fluorescence intensity over the surface of the object being studied and the wavelength of maximum fluorescent intensity. Such images provide a map of the structural integrity of the part being studied and weaknesses, particularly weaknesses created by exposure of the object to heat, are readily visible in the image. 6 figs.

  18. Method and apparatus for evaluating structural weakness in polymer matrix composites

    DOEpatents

    Wachter, Eric A.; Fisher, Walter G.

    1996-01-01

    A method and apparatus for evaluating structural weaknesses in polymer matrix composites is described. An object to be studied is illuminated with laser radiation and fluorescence emanating therefrom is collected and filtered. The fluorescence is then imaged and the image is studied to determine fluorescence intensity over the surface of the object being studied and the wavelength of maximum fluorescent intensity. Such images provide a map of the structural integrity of the part being studied and weaknesses, particularly weaknesses created by exposure of the object to heat, are readily visible in the image.

  19. An Evaluation of Matrix-Containing and Humanised Matrix-Free 3-Dimensional Cell Culture Systems for Studying Breast Cancer

    PubMed Central

    Roberts, Grace C.; Morris, Paul G.; Moss, Marcus A.; Maltby, Sarah L.; Palmer, Chelsea A.; Nash, Claire E.; Smart, Emily; Holliday, Deborah L.; Speirs, Valerie

    2016-01-01

    Background 3D cell cultures are emerging as more physiologically meaningful alternatives to monolayer cultures for many biological applications. They are attractive because they more closely mimic in vivo morphology, especially when co-cultured with stromal fibroblasts. Methodology/Principal Findings We compared the efficacy of 3 different 3D cell culture systems; collagen I, low attachment culture vessels and a modification of Fibrolife®, a specialised humanised cell culture medium devoid of animal-derived components, using breast cancer cell lines representative of the different molecular subtypes of breast cancer, cultured alone or with human mammary fibroblasts with a view to developing matrix-free humanised systems. 3D collagen I culture supported the growth of a range of breast cancer cell lines. By modifying the composition of Fibrolife® to epiFL, matrix-free cell culture was possible. During sequential transfer to epiFL breast cancer cells gradually detached from the flask, growing progressively as spheroids. Phenotype was stable and reversible with cells remaining actively proliferating and easily accessible throughout culture. They could also be revived from frozen stocks. To achieve co-culture with fibroblasts in epiFL required use of low attachment culture vessels instead of standard plastic as fibroblasts remained adherent in epiFL. Here, cancer cell spheroids were allowed to form before adding fibroblasts. Immunohistochemical examination showed fibroblasts scattered throughout the epithelial spheroid, not dissimilar to the relationship of tumour stroma in human breast cancer. Conclusions Because of its ease of handling, matrix-free 3D cell culture may be a useful model to study the influence of fibroblasts on breast cancer epithelial cells with use of epiFL culture medium taking this a step further towards a fully humanised 3D model. This methodology could be applied to other types of cancer cell lines, making this a versatile technique for cancer

  20. Comparing Two Different Methods to Evaluate Convariance-Matrix of Debris Orbit State in Collision Probability Estimation

    NASA Astrophysics Data System (ADS)

    Cheng, Haowen; Liu, Jing; Xu, Yang

    The evaluation of convariance-matrix is an inevitable step when estimating collision probability based on the theory. Generally, there are two different methods to compute convariance-matrix. One is so-called Tracking-Delta-Fitting method, first introduced when estimating the collision probability using TLE catalogue data, in which convariance-matrix is evaluated by fitting series of differences between propagated orbits of formal data and updated orbit data. In the second method, convariance-matrix is evaluated in the process of orbit determination. Both of the methods has there difficulties when introduced in collision probability estimation. In the first method, the value of convariance-matrix is evaluated based only on historical orbit data, ignoring information of latest orbit determination. As a result, the accuracy of the method strongly depends on the stability of convariance-matrix of latest updated orbit. In the second method, the evaluation of convariance-matrix is acceptable when the determined orbit satisfies weighted-least-square estimation, depending on the accuracy of observation error convariance, which is hard to obtain in real application, evaluated by analyzing the residuals of orbit determination in our research. In this paper we provided numerical tests to compare these two methods. A simulation of cataloguing objects in LEO, MEO and GEO regions has been carried out for a time span of 3 months. The influence of orbit maneuver has been included in GEO objects cataloguing simulation. For LEO objects cataloguing, the effect of atmospheric density variation has also been considered. At the end of the paper accuracies of evaluated convariance-matrix and estimated collision probability have been tested and compared.

  1. Evaluation of Concepts for Mulitiple Application Thermal Reactor for Irradiation eXperiments (MATRIX)

    SciTech Connect

    Michael A. Pope; Hans D. Gougar; John M. Ryskamp

    2013-09-01

    The Advanced Test Reactor (ATR) is a high power density test reactor specializing in fuel and materials irradiation. For more than 45 years, the ATR has provided irradiations of materials and fuels testing along with radioisotope production. Originally operated primarily in support of the Offcie of Naval Reactors (NR), the mission has gradually expanded to cater to other customers, such as the DOE Office of Nuclear Energy (NE), private industry, and universities. Unforeseen circumstances may lead to the decommissioning of ATR, thus leaving the U.S. Government without a large-scale materials irradiation capability to meet the needs of its nuclear energy and naval reactor missions. In anticipation of this possibility, work was performed under the Laboratory Directed Research and Development (LDRD) program to investigate test reactor concepts that could satisfy the current missions of the ATR along with an expanded set of secondary missions. This work can be viewed as an update to a project from the 1990’s called the Broad Application Test Reactor (BATR). In FY 2012, a survey of anticipated customer needs was performed, followed by analysis of the original BATR concepts with fuel changed to low-enriched uranium. Departing from these original BATR designs, four concepts were identified for further analysis in FY2013. The project informally adopted the acronym MATRIX (Multiple-Application Thermal Reactor for Irradiation eXperiments). This report discusses analysis of the four MATRIX concepts along with a number of variations on these main concepts. Designs were evaluated based on their satisfaction of anticipated customer requirements and the “Cylindrical” variant was selected for further analysis of options. This downselection should be considered preliminary and the backup alternatives should include the other three main designs. The baseline Cylindrical MATRIX design is expected to be capable of higher burnup than the ATR (or longer cycle length given a

  2. Matrix Photocatalytic, Inc. photocatalytic oxidation technology. Innovative technology evaluation report. Report for November 1994-November 1996

    SciTech Connect

    Topudurti, K.

    1997-05-01

    The report evaluates a photocatalytic oxidation technology`s ability to destroy volatile organic compounds (VOC) and other contaminants present in liquid wastes. Specifically, this report discusses performance and economic data from a Superfund Innovative Technology Evaluation (SITE) demonstration and one case study of the technology. This technology involves exposing titanium dioxide (TiO2) particles to ultraviolet (UV) light having a predominant wavelength of 254 nanometers. The TiO2 is activated by UV light to produce highly oxidizing hydroxyl radicals. Matrix also uses hydrogen peroxide and ozone to enhance the treatment system`s performance. Target organic compounds are either mineralized or broken down into low molecular weight organic compounds, primarily by hydroxyl radicals. The Matrix technology was demonstrated over a 2-week period in August and September 1995 at the K-25 Site of the U.S. Department of Energy Oak Ridge Reservation in Oak Ridge, Tennessee. Potential sites for applying this technology include Superfund and other hazardous waste sites where groundwater or other liquid wastes are contaminated with organic compounds.

  3. Formulation and evaluation of sustained release matrix tablet of rabeprazole using wet granulation technique

    PubMed Central

    Khan, Ruqaiyah; Ashraf, Md Shamim; Afzal, Muhammad; Kazmi, Imran; Jahangir, Mohammed Asadullah; Singh, Rajbala; Chandra, Ramesh; Anwar, Firoz

    2014-01-01

    Introduction: Rabeprazole, a member of substituted benzimidazoles, inhibits the final step in gastric acid secretions. This drug claims to cause fastest acid separation (due to higher pKa), and more rapidly converts to the active species to aid gastric mucin synthesis. The most significant pharmacological action of Rabeprazole is dose dependent suppression of gastric acid secretion; without anticholinergic or H2-blocking action. It completely abolishes the hydrochloric acid secretion as it is powerful inhibitor of gastric acid. Rabeprazole is acid labile and hence commonly formulated as an enteric coated tablet. The absorption of rabeprazole occurs rapidly as soon as tablet leaves the stomach. Aim: In the present study an attempt was made to formulate and evaluate Rabeprazole sustained release matrix tablet using wet granulation technique incorporating various polymers like HPMC-E15, Carbopol934, and sodium carboxymethyl cellulose (CMC). Materials and Methods: The Formulated tablets were evaluated for different physicochemical properties like rheological properties, weight variation, thickness, hardness, % friability, in vitro release studies and drug content. Results: Studies revealed that all the physicochemical parameters comply with the official standards. The in vitro release studies exhibits the release up to 90%, over a prolonged period of time which confirms the extended release profile of formulation, having better bioavailability as well as decreased dosing frequency with reduced doses. Conclusion: The sustained release matrix tablets of rabiprazole shown better bioavailability, efficacy and potency, when compared with official standards. PMID:25035637

  4. Preliminary evaluation of adhesion strength measurement devices for ceramic/titanium matrix composite bonds

    NASA Technical Reports Server (NTRS)

    Pohlchuck, Bobby; Zeller, Mary V.

    1992-01-01

    The adhesive bond between ceramic cement and a titanium matrix composite substrate to be used in the National Aerospace Plane program is evaluated. Two commercially available adhesion testers, the Sebastian Adherence Tester and the CSEM REVETEST Scratch Tester, are evaluated to determine their suitability for quantitatively measuring adhesion strength. Various thicknesses of cements are applied to several substrates, and bond strengths are determined with both testers. The Sabastian Adherence Tester has provided limited data due to an interference from the sample mounting procedure, and has been shown to be incapable of distinguishing adhesion strength from tensile and shear properties of the cement itself. The data from the scratch tester has been found to be difficult to interpret due to the porosity and hardness of the cement. Recommendations are proposed for a more reliable adhesion test method.

  5. Evaluation of Matrix9 silicon photomultiplier array for small-animal PET

    PubMed Central

    Du, Junwei; Schmall, Jeffrey P.; Yang, Yongfeng; Di, Kun; Roncali, Emilie; Mitchell, Gregory S.; Buckley, Steve; Jackson, Carl; Cherry, Simon R.

    2015-01-01

    Purpose: The MatrixSL-9-30035-OEM (Matrix9) from SensL is a large-area silicon photomultiplier (SiPM) photodetector module consisting of a 3 × 3 array of 4 × 4 element SiPM arrays (total of 144 SiPM pixels) and incorporates SensL’s front-end electronics board and coincidence board. Each SiPM pixel measures 3.16 × 3.16 mm2 and the total size of the detector head is 47.8 × 46.3 mm2. Using 8 × 8 polished LSO/LYSO arrays (pitch 1.5 mm) the performance of this detector system (SiPM array and readout electronics) was evaluated with a view for its eventual use in small-animal positron emission tomography (PET). Methods: Measurements of noise, signal, signal-to-noise ratio, energy resolution, flood histogram quality, timing resolution, and array trigger error were obtained at different bias voltages (28.0–32.5 V in 0.5 V intervals) and at different temperatures (5 °C–25 °C in 5 °C degree steps) to find the optimal operating conditions. Results: The best measured signal-to-noise ratio and flood histogram quality for 511 keV gamma photons were obtained at a bias voltage of 30.0 V and a temperature of 5 °C. The energy resolution and timing resolution under these conditions were 14.2% ± 0.1% and 4.2 ± 0.1 ns, respectively. The flood histograms show that all the crystals in the 1.5 mm pitch LSO array can be clearly identified and that smaller crystal pitches can also be resolved. Flood histogram quality was also calculated using different center of gravity based positioning algorithms. Improved and more robust results were achieved using the local 9 pixels for positioning along with an energy offset calibration. To evaluate the front-end detector readout, and multiplexing efficiency, an array trigger error metric is introduced and measured at different lower energy thresholds. Using a lower energy threshold greater than 150 keV effectively eliminates any mispositioning between SiPM arrays. Conclusions: In summary, the Matrix9 detector system can resolve

  6. Analytical techniques for the evaluation of asymptotic matrix elements in electromagnetic problems

    NASA Astrophysics Data System (ADS)

    Park, Seong-Ook

    1997-07-01

    Analytical solutions of the asymptotic part of impedance matrix elements, whose integrand contains either a singularity or exhibits a strongly oscillatory behavior, are developed for the analysis of various geometries. These developed formulas are applied using the Method of Moments (MoM), to the analysis of wire antennas, planar transmission lines, and printed circuits including microstrip dipoles, asymmetric gap discontinuities, and arbitrary shapes of planar circuits, where computational speed and accuracy are important. The first example considered is the singularity treatment in integrands of wire-type antenna problems. To overcome the problem, first the singularity is subtracted out, and then this part is integrated analytically in the transform domain. Asymptotic matrix elements of the multilayer planar transmission lines are solved analytically by using Chebyshev polynomial basis functions in the spectral domain. These results are applied to open and coupled microstrip lines. The analysis of printed circuits involves Sommerfeld-type integrals which are extremely difficult to evaluate. To enhance the speed and accuracy of Sommerfeld-type integrals, this dissertation, for the first time, presents an analytical transformation technique. This formulation allows the infinite double integral of the asymptotic part of the impedance matrix to be transformed into a finite one-dimensional integral. Using this approach, the asymptotic part of self and mutual interactions between the triangular edge mode basis functions, along an electrically narrow strip, is solved analytically. These results are applied to microstrip dipoles and asymmetric gap discontinuities. This formula provides highly accurate results with minimal computational effort. This work is also extended to roof- top subdomain basis functions, and the obtained results can be used to solve arbitrarily shaped planar geometries. As an example, computed results of the Radar Cross Section (RCS) of a microstrip

  7. Formulation and evaluation of controlled release matrix mucoadhesive tablets of domperidone using Salvia plebeian gum

    PubMed Central

    Arora, Gurpreet; Malik, Karan; Singh, Inderbir; Arora, Sandeep; Rana, Vikas

    2011-01-01

    The aim of study was to prepare controlled release matrix mucoadhesive tablets of domperidone using Salvia plebeian gum as natural polymer. Tablets were formulated by direct compression technology employing the natural polymer in different concentrations (5, 10, 15 and 20% w/w). The prepared batches were evaluated for drug assay, diameter, thickness, hardness and tensile strength, swelling index, mucoadhesive strength (using texture analyzer) and subjected to in vitro drug release studies. Real-time stability studies were also conducted on prepared batches. In vitro drug release data were fitted in various release kinetic models for studying the mechanism of drug release. Tensile strength was found to increase from 0.808 ± 0.098 to 1.527 ± 0.10 mN/cm2 and mucoadhesive strength increased from 13.673 ± 1.542 to 40.378 ± 2.345 N, with an increase in the polymer concentration from 5 to 20% (A1 to A4). Swelling index was reported to increase with both increase in the concentration of gum and the time duration. The in vitro drug release decreased from 97.76 to 83.4% (A1 to A4) with the increase in polymer concentration. The drug release from the matrix tablets was found to follow zero-order and Higuchi models, indicating the matrix-forming potential of natural polymer. The value of n was found to be between 0.5221 and 0.8992, indicating the involvement of more than one drug release mechanism from the formulation and possibly the combination of both diffusion and erosion. These research findings clearly indicate the potential of S. plebeian gum to be used as binder, release retardant and mucoadhesive natural material in tablet formulations. PMID:22171313

  8. Different matrix evaluation for the bone regeneration of rats' femours using time domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Rusu, Laura-Cristina; Negrutiu, Meda Lavinia; Sinescu, Cosmin; Hoinoiu, Bogdan; Zaharia, Cristian; Ardelean, Lavinia; Duma, Virgil-Florin; Podoleanu, Adrian G.

    2014-01-01

    The osteoconductive materials are important in bone regeneration procedures. Three dimensional (3D) reconstructions were obtained from the analysis. The aim of this study is to investigate the interface between the femur rat bone and the new bone that is obtained using a method of tissue engineering that is based on two artificial matrixes inserted in previously artificially induced defects. For this study, under strict supervision 20 rats were used in conformity with ethical procedures. In all the femurs a round defect was induced by drilling with a 1 mm spherical Co-Cr surgical drill. The matrixes used were IngeniOss (for ten samples) and 4Bone(for the other ten samples). These materials were inserted into the induced defects. The femurs were investigated at 1 month, after the surgical procedures. The interfaces were examined using Time Domain (TD) Optical Coherence Tomography (OCT) combined with Confocal Microscopy (CM). The scanning procedure is similar to that used in any CM, where the fast scanning is en-face (line rate) and the scanning in depth is much slower (at the frame rate). The optical configuration uses two single mode directional couplers with a superluminiscent diode as the source centered at 1300 nm. The results showed open interfaces due to the insufficient healing process, as well as closed interfaces due to a new bone formation inside the defect. The conclusion of this study is that TD-OCT can act as a valuable tool in the investigation of the interface between the old bone and the one that has been newly created due to the osteoinductive process. The TD-OCT has proven a valuable tool for the non-invasive evaluation of the matrix bone interfaces.

  9. Radiographic and histological evaluation of ectopic application of deproteinized bovine bone matrix

    PubMed Central

    da Silva, Rodrigo Carlos; Crivellaro, Viviane Rozeira; Giovanini, Allan Fernando; Scariot, Rafaela; Gonzaga, Carla Castiglia; Zielak, João César

    2016-01-01

    Objective: To evaluate, through radiographic and histological analysis, the tissue reaction induced by a biomaterial based on deproteinized bovine bone matrix (DBBM) in the muscle of sheep. Materials and Methods: Sixteen sheep were used. The animals underwent surgery to insert polyethylene tubes containing the biomaterial in the muscle of the lower back (ectopic site) and were euthanized after 3 and 6 months. Each sheep received three tubes: Group 1 - sham group (negative control - tube without biomaterial), Group 2 - particulate autogenous bone (positive control), and Group 3 - DBBM biomaterial (GenOx Inorg). The material removed was evaluated by radiographic, macroscopic, and microscopic analysis, descriptively. Results: Macroscopic analysis showed that Group 3 had a greater tissue volume maintenance. Microscopic analysis indicated that Group 1 had a higher concentration of dense, thin collagen fibers (3 and 6 months); in Group 2, there was a decrease in the inflammatory process and the deposition of dense, thin collagen fibers (3 and 6 months); in Group 3, the presence of a dense connective tissue was noted, in which the DBBM particles (3 months) were found. On the periphery of these particles, a deposition of basophilic material was found, indicating the formation of mineral particles and the formation of tissues with osteoid characteristics (6 months). Conclusion: Based on the results obtained, it can be concluded that the biomaterial based on DBBM led to the formation of tissue with similar characteristics to an osteoid matrix in a postoperative period of 6 months. However, none of the groups evaluated showed ectopic bone neoformation. PMID:27563599

  10. Evaluation of several micromechanics models for discontinuously reinforced metal matrix composites

    NASA Technical Reports Server (NTRS)

    Johnson, W. Steven; Birt, M. J.

    1990-01-01

    A systematic experimental evaluation of whisker and particulate reinforced aluminum matrix composites was conducted to assess the variation in tensile properties with reinforcement type, volume fraction, and specimen thickness. Each material was evaluated in three thicknesses, 1.8, 3.18, and 6.35 mm, to determine the size, distribution, and orientation of the reinforcements. This information was used to evaluate several micromechanical models that predict composite moduli. The longitudinal and transverse moduli were predicted for reinforced aluminum. The Paul model, the Cox model and the Halpin-Tsai model were evaluated. The Paul model gave a good upper bound prediction for the particulate reinforced composites but under predicted whisker reinforced composite moduli. The Cox model gave good moduli predictions for the whisker reinforcement, but was too low for the particulate. The Halpin-Tsai model gave good results for both whisker and particulate reinforced composites. An approach using a trigonometric projection of whisker length to predict the fiber contribution to the modulus in the longitudinal and transverse directions was compared to the more conventional lamination theory approach.

  11. Evaluation of Ceramic Matrix Composite Technology for Aircraft Turbine Engine Applications

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.; Jaskowiak, Martha H.; Kiser, James D.; Zhu, Dongming

    2013-01-01

    The goals of the NASA Environmentally Responsible Aviation (ERA) Project are to reduce the NO(x) emissions, fuel burn, and noise from turbine engines. In order to help meet these goals, commercially-produced ceramic matrix composite (CMC) components and environmental barrier coatings (EBCs) are being evaluated as parts and panels. The components include a CMC combustor liner, a CMC high pressure turbine vane, and a CMC exhaust nozzle as well as advanced EBCs that are tailored to the operating conditions of the CMC combustor and vane. The CMC combustor (w/EBC) could provide 2700 F temperature capability with less component cooling requirements to allow for more efficient combustion and reductions in NOx emissions. The CMC vane (w/EBC) will also have temperature capability up to 2700 F and allow for reduced fuel burn. The CMC mixer nozzle will offer reduced weight and improved mixing efficiency to provide reduced fuel burn. The main objectives are to evaluate the manufacturability of the complex-shaped components and to evaluate their performance under simulated engine operating conditions. Progress in CMC component fabrication, evaluation, and testing is presented in which the goal is to advance from the proof of concept validation (TRL 3) to a system/subsystem or prototype demonstration in a relevant environment (TRL 6).

  12. An Analysis of Nondestructive Evaluation Techniques for Polymer Matrix Composite Sandwich Materials

    NASA Technical Reports Server (NTRS)

    Cosgriff, Laura M.; Roberts, Gary D.; Binienda, Wieslaw K.; Zheng, Diahua; Averbeck, Timothy; Roth, Donald J.; Jeanneau, Philippe

    2006-01-01

    Structural sandwich materials composed of triaxially braided polymer matrix composite material face sheets sandwiching a foam core are being utilized for applications including aerospace components and recreational equipment. Since full scale components are being made from these sandwich materials, it is necessary to develop proper inspection practices for their manufacture and in-field use. Specifically, nondestructive evaluation (NDE) techniques need to be investigated for analysis of components made from these materials. Hockey blades made from sandwich materials and a flat sandwich sample were examined with multiple NDE techniques including thermographic, radiographic, and shearographic methods to investigate damage induced in the blades and flat panel components. Hockey blades used during actual play and a flat polymer matrix composite sandwich sample with damage inserted into the foam core were investigated with each technique. NDE images from the samples were presented and discussed. Structural elements within each blade were observed with radiographic imaging. Damaged regions and some structural elements of the hockey blades were identified with thermographic imaging. Structural elements, damaged regions, and other material variations were detected in the hockey blades with shearography. Each technique s advantages and disadvantages were considered in making recommendations for inspection of components made from these types of materials.

  13. Evaluation of mucilage of Hibiscus rosasinensis Linn as rate controlling matrix for sustained release of diclofenac.

    PubMed

    Jani, Girish K; Shah, Dhiren P

    2008-08-01

    This article reports the exploitation of novel hydrophilic excipient, that is, mucilage from Hibiscus rosasinensis Linn, for the development of sustained release tablet. Swelling ratio and flow properties analyses of dried mucilage powder were carried out. A 3(2) full factorial design was used. In factorial design, amounts of dried mucilage and dibasic calcium phosphate (DCP) were taken as independent factors and percentage drug release in 60 and 300 min and time for 80% drug release as dependent variables. Matrix tablet containing dried mucilage and diclofenac sodium (DS) was prepared through direct compression techniques. DS tablets were evaluated for hardness, friability, weight variation, in vitro drug release and water uptake, and mass loss study. The dried mucilage powder shows superior swelling capacity and excellent flow properties. Prepared tablets have acceptable hardness, friability, and uniformity in weight. It was found that batch HD8 fulfills all selected criteria. Drug release kinetics from these formulations corresponded best to the zero-order kinetics. Water uptake was independent whereas mass loss was dependent on agitation speed. The concept of similarity factor (f(2)) was used to prove similarity of dissolution profile in distilled water and phosphate buffer and was found to be 90.68. It was concluded that mucilage can be used as release-retarding agent for 12 h when the drug-mucilage ratio was 1:1.5. So, matrix tablet containing dried mucilage is most suitable for sustained release of DS. PMID:18686091

  14. Lornoxicam gastro retentive floating matrix tablets: Design and in vitro evaluation

    PubMed Central

    Sathiyaraj, S.; Devi, Ramya D.; Hari, Vedha B. N.

    2011-01-01

    The objective of this present investigation is to prolong the gastric residence time of Lornoxicam by fabricating it into a floating sustained release matrix tablets. Lornoxicam, a potent oxicam group of non-steroidal anti-inflammatory drugs, suffers from relatively short half life of 2 to 3 hrs showing maximal absorption in proximal gastro intestinal tract region necessitating its need to be formulated as a floating sustained release matrix tablets. In this current investigation, hydroxyl propyl methyl cellulose K15M, a high viscous grade polymer with apparent viscosity of 15,000 cps, was kept as a variable (10-50%) and calcium carbonate (13%) was used as a gas generator. The prepared blends were subjected for its pre-formulation characterization. The directly compressed tablets were evaluated for physical parameters such as weight uniformity, hardness, friability, drug content, in-vitro buoyancy with axial and radial enlargement measurement, swelling index. From the investigation it was observed that the buoyancy lasted for up to 24 hrs. Fourier transform infra-red spectroscopy peaks assured the compatibility of the drug with excipients and confirmed the presence of pure drug in the formulation. It was supported by in-vitro dissolution studies; and the dissolution data was subjected to various release kinetic models to understand the mechanism of drug release. PMID:22171312

  15. Bioavailability of food folates and evaluation of food matrix effects with a rat bioassay.

    PubMed

    Clifford, A J; Heid, M K; Peerson, J M; Bills, N D

    1991-04-01

    Folate bioavailability of beef liver, lima beans, peas, spinach, mushrooms, collards, orange juice and wheat germ was estimated with a protocol of folate depletion-repletion using growth and liver, serum and erythrocyte folate of weanling male rats. Diets with 125, 250 and 375 micrograms folic acid/kg were standards. Individual foods were incorporated into a folate-free amino acid-based diet alone (250 micrograms folate/kg diet from food) or mixed with folic acid (125 micrograms folate from food + 125 micrograms folic acid) to evaluate folate bioavailability and effects of food matrix. Beef liver and orange juice folates were as available as folic acid, whereas those of wheat germ were less bioavailable. Folates of peas and spinach were also less available than folic acid using liver and serum folate concentrations and total liver folate as response criteria, but they were not lower when based on growth and erythrocyte folate concentrations. Lima bean, mushroom and collard folates were as available as folic acid using four of five response criteria. Folate bioavailability of all foods generally exceeded 70%. All response criteria gave approximately equivalent results, indicating that growth and tissue folate levels are appropriate criteria. No food matrix effects were observed for any food except lima beans. Foods rich in polyglutamyl folates were less bioavailable than those of foods rich in short-chain folates. PMID:2007897

  16. Scattering matrix analysis for evaluating the photocurrent in hydrogenated-amorphous-silicon-based thin film solar cells.

    PubMed

    Shin, Myunghun; Lee, Seong Hyun; Lim, Jung Wook; Yun, Sun Jin

    2014-11-01

    A scattering matrix (S-matrix) analysis method was developed for evaluating hydrogenated amorphous silicon (a-Si:H)-based thin film solar cells. In this approach, light wave vectors A and B represent the incoming and outgoing behaviors of the incident solar light, respectively, in terms of coherent wave and incoherent intensity components. The S-matrix determines the relation between A and B according to optical effects such as reflection and transmission, as described by the Fresnel equations, scattering at the boundary surfaces, or scattering within the propagation medium, as described by the Beer-Lambert law and the change in the phase of the propagating light wave. This matrix can be used to evaluate the behavior of angle-incident coherent and incoherent light simultaneously, and takes into account not only the light scattering process at material boundaries (haze effects) but also nonlinear optical processes within the material. The optical parameters in the S-matrix were determined by modeling both a 2%-gallium-doped zinc oxide transparent conducting oxide and germanium-compounded a-Si:H (a-SiGe:H). Using the S-matrix equations, the photocurrent for an a-Si:H/a-SiGe:H tandem cell and the optical loss in semitransparent a-Si:H solar cells for use in building-integrated photovoltaic applications were analyzed. The developed S-matrix method can also be used as a general analysis tool for various thin film solar cells. PMID:25958519

  17. Vibrational Spectroscopic Imaging for the Evaluation of Matrix and Mineral Chemistry

    PubMed Central

    Gamsjaeger, S.; Mendelsohn, R.; Boskey, A. L.; Gourion-Arsiquaud, S.; Klaushofer, K.

    2015-01-01

    Metabolic bone diseases manifesting fragility fractures (such as osteoporosis) are routinely diagnosed based on bone mineral density (BMD) measurements, and the effect of various therapies also evaluated based on the same outcome. Although useful, it is well recognized that this metric does not fully account for either fracture incidence or the effect of various therapies on fracture incidence, thus, the emergence of bone quality as a contributing factor in the determination of bone strength. Infrared and Raman vibrational spectroscopic techniques are particularly well-suited for the determination of bone quality as they provide quantitative and qualitative information of the mineral and organic matrix bone components, simultaneously. Through the use of microspectroscopic techniques, this information is available in a spatially resolved manner, thus, the outcomes may be easily correlated with outcomes from techniques such as histology, histomorphometry, and nanoindentation, linking metabolic status with material properties. PMID:25240579

  18. Colorimetric characterization models based on colorimetric characteristics evaluation for active matrix organic light emitting diode panels.

    PubMed

    Gong, Rui; Xu, Haisong; Tong, Qingfen

    2012-10-20

    The colorimetric characterization of active matrix organic light emitting diode (AMOLED) panels suffers from their poor channel independence. Based on the colorimetric characteristics evaluation of channel independence and chromaticity constancy, an accurate colorimetric characterization method, namely, the polynomial compensation model (PC model) considering channel interactions was proposed for AMOLED panels. In this model, polynomial expressions are employed to calculate the relationship between the prediction errors of XYZ tristimulus values and the digital inputs to compensate the XYZ prediction errors of the conventional piecewise linear interpolation assuming the variable chromaticity coordinates (PLVC) model. The experimental results indicated that the proposed PC model outperformed other typical characterization models for the two tested AMOLED smart-phone displays and for the professional liquid crystal display monitor as well. PMID:23089779

  19. Application of neural networks in the acousto-ultrasonic evaluation of metal-matrix composite specimens

    NASA Technical Reports Server (NTRS)

    Cios, Krzysztof J.; Tjia, Robert E.; Vary, Alex; Kautz, Harold E.

    1992-01-01

    Acousto-ultrasonics (AU) is a nondestructive evaluation (NDE) technique that was devised for the testing of various types of composite materials. A study has been done to determine how effectively the AU technique may be applied to metal-matrix composites (MMCs). The authors use the results and data obtained from that study and apply neural networks to them, particularly in the assessment of mechanical property variations of a specimen from AU measurements. It is assumed that there is no information concerning the important features of the AU signal which relate to the mechanical properties of the specimen. Minimally processed AU measurements are used while relying on the network's ability to extract the significant features of the signal.

  20. Evaluation of Johnson-Cook model constants for aluminum based particulate metal matrix composites

    NASA Astrophysics Data System (ADS)

    Hilfi, H.; Brar, N. S.

    1996-05-01

    High strain rate and high temperature response of three types of aluminum based particulate metal matrix ceramic composites is investigated by performing split Hopkinson pressure bar (SHPB) experiments. The composites are: NGP-2014 (15% SiC), NGT-6061 (15% SiC), and NGU-6061 (15% Al2O3), in which all the reinforcement materials are percentage by volume. Johnson-Cook constitutive model constants are evaluated from the high strain rate/high temperature data and implemented in a two dimensional finite element computer code (EPIC-2D) to simulate the penetration of an ogive nose tungsten projectile (23 grams) at a velocity 1.17 km/sec into the base 6061-T6 aluminum alloy and the composite NGU-6061. The simulated penetrations in the composite and in 6061-T6 aluminum agree with in 2%, in both materials, with the measured values.

  1. Evaluation of the Technical-Economic Potential of Particle- Reinforced Aluminum Matrix Composites and Electrochemical Machining

    NASA Astrophysics Data System (ADS)

    Schubert, A.; Götze, U.; Hackert-Oschätzchen, M.; Lehnert, N.; Herold, F.; Meichsner, G.; Schmidt, A.

    2016-03-01

    Compared to conventional cutting, the processing of materials by electrochemical machining offers some technical advantages like high surface quality, no thermal or mechanical impact on the work piece and preservation of the microstructure of the work piece material. From the economic point of view, the possibility of process parallelization and the absence of any process-related tool wear are mentionable advantages of electrochemical machining. In this study, based on experimental results, it will be evaluated to what extent the electrochemical machining is technically and economically suitable for the finish-machining of particle- reinforced aluminum matrix composites (AMCs). Initial studies showed that electrochemical machining - in contrast to other machining processes - has the potential to fulfil demanding requirements regarding precision and surface quality of products or components especially when applied to AMCs. In addition, the investigations show that processing of AMCs by electrochemical machining requires less energy than the electrochemical machining of stainless steel. Therefore, an evaluation of electrochemically machined AMCs - compared to stainless steel - from a technical and an economic perspective will be presented in this paper. The results show the potential of electro-chemically machined AMCs and contribute to the enhancement of instruments for technical-economic evaluations as well as a comprehensive innovation control.

  2. Revisiting the link between breeding effort and oxidative balance through field evaluation of two sympatric sibling insect species.

    PubMed

    Rey, Benjamin; Pélisson, Pierre-François; Bel-Venner, Marie-Claude; Voituron, Yann; Venner, Samuel

    2015-03-01

    The idea that oxidative stress could be a major force governing evolutionary trade-offs has recently been challenged by experimental approaches in laboratory conditions, triggering extensive debates centered on theoretical and methodological issues. Here, we revisited the link between oxidative stress and reproduction by measuring multiple antioxidant and oxidative damages in wild-caught females of two sibling weevil species (Curculio elephas, C. glandium). The strength of our study arised from (1) studied species that were sympatric and exploited similar resource, but displayed contrasting reproductive strategies and (2) individuals were sampled throughout adult life so as to relate oxidative status to breeding effort. We found that the short-lived C. elephas sacrifices red-ox homeostasis for immediate reproduction upon emergence as characterized by low antioxidant defenses and elevated oxidative damage. Comparatively, C. glandium massively invests in antioxidant and maintains low oxidative damage, which may contribute to their extended prereproductive period. Intriguingly, we also reveal, for the first time in a field study, an unexpected reactivation of antioxidant defenses with the onset of reproduction. Our results thus support the existence of a strong, but complex relationship between oxidative stress and life-history evolution and highlight the need for a finer-scale picture of antioxidant strategies. PMID:25521015

  3. Formulation and in vitro, in vivo evaluation of extended- release matrix tablet of zidovudine: influence of combination of hydrophilic and hydrophobic matrix formers.

    PubMed

    Kuksal, Atul; Tiwary, Ashok K; Jain, Narendra K; Jain, Subheet

    2006-01-01

    The aim of the present study was to prepare and characterize extended-release matrix tablets of zidovudine using hydrophilic Eudragit RLPO and RSPO alone or their combination with hydrophobic ethyl cellulose. Release kinetics was evaluated by using United States Pharmacopeia (USP)-22 type I dissolution apparatus. Scanning electron microscopy was used to visualize the effect of dissolution medium on matrix tablet surface. Furthermore, the in vitro and in vivo newly formulated sustained-release zidovudine tablets were compared with conventional marketed tablet (Zidovir, Cipla Ltd, Mumbai, India). The in-vitro drug release study revealed that either Eudragit preparation was able to sustain the drug release only for 6 hours (94.3% +/- 4.5% release). Combining Eudragit with ethyl cellulose sustained the drug release for 12 hours (88.1% +/- 4.1% release). Fitting the in vitro drug release data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release. In vivo investigation in rabbits showed sustained-release pharmacokinetic profile of zidovudine from the matrix tablets formulated using combination of Eudragits and ethylcellulose. In conclusion, the results suggest that the developed sustained-release tablets of zidovudine could perform therapeutically better than conventional dosage forms, leading to improve efficacy and better patient compliance. PMID:16584139

  4. Evaluation of Matrix9 silicon photomultiplier array for small-animal PET

    SciTech Connect

    Du, Junwei Schmall, Jeffrey P.; Yang, Yongfeng; Di, Kun; Roncali, Emilie; Mitchell, Gregory S.; Buckley, Steve; Jackson, Carl; Cherry, Simon R.

    2015-02-15

    Purpose: The MatrixSL-9-30035-OEM (Matrix9) from SensL is a large-area silicon photomultiplier (SiPM) photodetector module consisting of a 3 × 3 array of 4 × 4 element SiPM arrays (total of 144 SiPM pixels) and incorporates SensL’s front-end electronics board and coincidence board. Each SiPM pixel measures 3.16 × 3.16 mm{sup 2} and the total size of the detector head is 47.8 × 46.3 mm{sup 2}. Using 8 × 8 polished LSO/LYSO arrays (pitch 1.5 mm) the performance of this detector system (SiPM array and readout electronics) was evaluated with a view for its eventual use in small-animal positron emission tomography (PET). Methods: Measurements of noise, signal, signal-to-noise ratio, energy resolution, flood histogram quality, timing resolution, and array trigger error were obtained at different bias voltages (28.0–32.5 V in 0.5 V intervals) and at different temperatures (5 °C–25 °C in 5 °C degree steps) to find the optimal operating conditions. Results: The best measured signal-to-noise ratio and flood histogram quality for 511 keV gamma photons were obtained at a bias voltage of 30.0 V and a temperature of 5 °C. The energy resolution and timing resolution under these conditions were 14.2% ± 0.1% and 4.2 ± 0.1 ns, respectively. The flood histograms show that all the crystals in the 1.5 mm pitch LSO array can be clearly identified and that smaller crystal pitches can also be resolved. Flood histogram quality was also calculated using different center of gravity based positioning algorithms. Improved and more robust results were achieved using the local 9 pixels for positioning along with an energy offset calibration. To evaluate the front-end detector readout, and multiplexing efficiency, an array trigger error metric is introduced and measured at different lower energy thresholds. Using a lower energy threshold greater than 150 keV effectively eliminates any mispositioning between SiPM arrays. Conclusions: In summary, the Matrix9 detector system

  5. Evaluation of hepatocellular carcinoma aggressiveness by a panel of extracellular matrix antigens.

    PubMed Central

    Grigioni, W. F.; Garbisa, S.; D'Errico, A.; Baccarini, P.; Stetler-Stevenson, W. G.; Liotta, L. A.; Mancini, A. M.

    1991-01-01

    Invasion and metastasis requires a series of interactions between malignant cells and the extracellular matrix (ECM). Antigen markers that relate to these interactions were evaluated for prognostic correlation in human hepatocellular carcinoma. Basement membrane type IV collagen (cIV), type IV collagenase (cIVase), laminin, and laminin receptors (LRs)--all ECM antigens previously proposed to be modulated in association with tumor aggressiveness--were immunohistochemically investigated in 30 cases of hepatocellular carcinomas (HCCs). The pattern of antigen expression was correlated with 1) 36 months' clinical follow-up and 2) the pathologic grade. As a means of estimating the proliferation fraction, an additional antigen, Ki67, was also studied in this series. There were major differences in the distribution of cIV and laminin, and in the quantity of cIVase-, LR-, and Ki67-positive cells associated with grade and prognosis. A smaller quantity of cIV and laminin and a higher number of cIVase-, LR-, and Ki67-positive cells were detected in the poorly differentiated compared with the well-differentiated HCCs. The tumors with lower immunoreactivity for cIV and laminin components accompanied by a higher number of cIVase-, LR-, and Ki67-positive cells fall into a group with the poorest overall survival (P less than 0.006). The panel of antigens is proposed as a useful prognostic tool for evaluating HCC tumor aggressiveness. Images Figure 2 Figure 3 Figure 4 PMID:1848041

  6. Preparation and evaluation of an ispaghula based directly compressible matrixing agent for controlled release.

    PubMed

    Lalwani, Anita N; Parikh, Jolly R

    2008-09-01

    The objective of the present investigation was to prepare and evaluate an ispaghula husk based directly compressible (DC) adjuvant that can be used as matrixing agent using an agglomeration technique. Addition of hydroxypropyl methylcellulose was found necessary to improve cohesion. Lactose (X1), calcium hydrogen phosphate dihydrate (X2) and Avicel PH101 (X3), used along with ispaghula in preparation of agglomerates, were selected as three independent variables in a simplex lattice design affecting compressional and dissolution characteristics of the drug from the DC adjuvant. The agglomerates were evaluated for their flow properties. Tablets were prepared using 70% agglomerates and 30% acetaminophen, a poorly compressible drug, and were subjected to in vitro drug release study. Amounts of the drug released at the end of 60 min (Y60), 300 min (Y300) and 480 min (Y480) were selected as dependent variables in a simplex lattice design. Batch IH05 that contained lactose and calcium hydrogen phosphate dihydrate in a 1:2 ratio could control the release for 12 hours and thus form the basis for twice a-day-dosing. PMID:19103567

  7. Rapid pentachlorophenol evaluation in solid matrixes by second derivative UV spectroscopy for application to wood and leather samples

    SciTech Connect

    Secchieri, M.; Benassi, C.A.; Pastore, S.; Semenzato, A.; Bettero, A.; Levorato, M.; Guerrato, A. )

    1991-07-01

    A method for the quail-quantitative evaluation of pentachlorophenol (PCP) in solid matrixes has been developed. The procedure is based on solid-liquid extraction of solid samples (leather or wood), followed by purification on a cyanopropyl column and determination of the preservative by second derivative UV spectroscopy considering the PCP A peak-through value (304-297 nm). The method allows rapid PCP determination in the concentration range 1-40 micrograms/mL; any matrix interference is avoided by the purification step and recoveries of the preservative were 99.12% (RSD% 0.13) for the leather matrix and 98.03 (RSD% 0.17) for the wood matrix.

  8. Fiber-matrix interface studies on bioabsorbable composite materials for internal fixation of bone fractures. I. Raw material evaluation and measurement of fiber-matrix interfacial adhesion.

    PubMed

    Slivka, M A; Chu, C C; Adisaputro, I A

    1997-09-15

    The objective of this study was to characterize and evaluate the performance of various fiber-matrix composite systems by studying the mechanical, thermal, and physical properties of the fiber and matrix components, and by studying the fiber-matrix interface adhesion strength using both microbond and fragmentation methods. The composites studies were poly(L-lactic acid) (PLLA) matrix reinforced with continuous fibers of either nonabsorbable AS4 carbon (C), absorbable calcium phosphate (CaP), poly(glycolic acid) (PGA), or chitin. Carbon and CaP single fibers had high Young's moduli and failed in a brittle manner. PGA and chitin single fibers had relatively lower Young's moduli and relatively higher ductility. Upon in vitro hydrolysis, CaP fibers retained 17% of their tensile strength and 39% of their Young's modulus after 12 h, PCA fibers retained 10% of their tensile strength and 52% of their Young's modulus after 16 days, and chitin fibers retained 87% of their tensile strength and 130% of their Young's modulus after 25 days. PLLA films had much lower strength and Young's moduli, but much higher ductility relative to the single fibers. Using the microbond method, the initial fiber-matrix interfacial shear strength (IFSS) of C/PLLA and CaP/PLLA microcomposites was 33.9 and 12.6 MPa, respectively. Upon in vitro hydrolysis, C/PLLA retained 49% of IFSS after 15 days and CaP/PLLA retained 46% of IFSS after 6 h. Using a fiber fragmentation method, the initial IFSS of C/PLLA, CaP/PLLA, and chitin/ PLLA was 22.2, 15.6, and 28.3 MPa, respectively. The performance of carbon fibers and C/PLLA composites was superior to the other fibers and fiber/PLLA systems, but the carbon fiber was nonabsorbable. CaP had the most suitable modulus of the absorbable fibers for fixing cortical bone fracture, but its rapid deterioration of mechanical properties and loss of IFSS limits its use. PGA and chitin fibers had suitable mechanical properties and their retention for fixing cancellous

  9. Semi solid matrix formulations of meloxicam and tenoxicam: an in vitro and in vivo evaluation.

    PubMed

    Alladi, Saritha; Shastri, Nalini R

    2015-01-01

    The objective of this study was to improve the dissolution and subsequently the therapeutic efficacy of poorly water soluble BCS class-II drugs meloxicam and tenoxicam, by lipid semi solid matrix (SSM) systems filled in hard gelatin capsules by liquid fill technology. The present research involved preparation of SSM formulations using Gelucire 44/14 as a carrier due to its self emulsifying, wetting and hydrophilic properties. The SSM capsules were characterized by assay, in vitro dissolution studies, moisture uptake, FTIR and DSC. The optimized formulations were also evaluated for their in vivo anti inflammatory activity in rat model. Six to ten fold enhancement in vitro drug release, in both acidic and basic media, was obtained with formulations containing drug to carrier in 1:6 ratio. The absence of drug peak in DSC scans indicated complete dissolution of the drug in carrier, while IR revealed no chemical interaction of pure drug and Gelucire 44/14. The optimized SSM formulations of meloxicam and tenoxicam showed a rapid decrease in paw edema with a significant increase in anti-inflammatory activity. The SSM formulations were successful in providing rapid release of drugs with improved dissolution and in vivo anti-inflammatory activity by liquid fill technology in hard gelatin capsules. PMID:24752862

  10. Fabrication and biological evaluation of uniform extracellular matrix coatings on discontinuous photolithography generated micropallet arrays

    PubMed Central

    Gunn, Nicholas M.; Bachman, Mark; Li, Guann-Pyng; Nelson, Edward L.

    2010-01-01

    ABSTRACT/SYNOPSIS The recent identification of rare cell populations within tissues that are associated with specific biological behaviors, e.g., progenitor cells, has illuminated a limitation of current technologies to study such adherent cells directly from primary tissues. The micropallet array is a recently developed technology designed to address this limitation by virtue of its capacity to isolate and recover single adherent cells on individual micropallets. The capacity to apply this technology to primary tissues and cells with restricted growth characteristics, particularly adhesion requirements, is critically dependent upon the capacity to generate functional extracellular matrix (ECM) coatings. The discontinuous nature of the micropallet array surface provides specific constraints on the processes for generating the desired ECM coatings that are necessary to achieve the full functional capacity of the micropallet array. We have developed strategies, reported herein, to generate functional coatings with various ECM protein components: fibronectin, EHS tumor basement membrane extract, collagen, and laminin-5; confirmed by evaluation for rapid cellular adherence of four dissimilar cell types: fibroblast, breast epithelial, pancreatic epithelial, and myeloma. These findings are important for the dissemination and expanded use of micropallet arrays and similar microtechnologies requiring the integrated use of ECM protein coatings to promote cellular adherence. PMID:20648537

  11. R-Matrix Evaluation of {sup 16}O neutron cross sections up to 6.3 MeV

    SciTech Connect

    Sayer, R.O.; Leal, L.C.; Larson, N.M.; Spencer, R.R.; and Wright, R.Q.

    2000-08-01

    In this paper the authors describe an evaluation of {sup 16}O neutron cross sections in the resolved resonance region with the multilevel Reich-Moore R-matrix formalism. Resonance analyses were performed with the computer code SAMMY [LA98] which utilizes Bayes' method, a generalized least squares technique.

  12. EVALUATION OF GAS CHROMATOGRAPHY/MATRIX ISOLATION INFRARED SPECTROMETRY FOR THE DETERMINATION OF SEMIVOLATILE ORGANIC COMPOUNDS IN AIR SAMPLE EXTRACTS

    EPA Science Inventory

    The capabilities of gas chromatography/matrix isolation-infrared (GC/MI-IR) spectrometry for determination of semivolatile organic compounds (SVOCs) in air sample extracts were evaluated. ystematic experiment, using xylene isomers as test compounds, were conducted to determine th...

  13. Establishing Fair and Realistic Entry and Exit Criteria Using the General Evaluation Matrix (GEM), a Special Education Decision Making Tool.

    ERIC Educational Resources Information Center

    Maxwell, Kenneth G.

    The paper describes the development and use of a General Evaluation Matrix (GEM), a profile technique by which major handicaps are graphically presented along with school grades and achievements in basic skills. The approach lends itself to establishing entry level criteria for special education suited to the needs of specific communities.…

  14. Evaluation of bioabsorbable elastin-fibrin matrix as a barrier in surgical periodontal treatment.

    PubMed

    Da Costa-Noble, R; Soustre, E C; Cadot, S; Lauverjat, Y; Lefebvre, F; Rabaud, M

    1996-09-01

    The purpose of this investigation was to test clinically the efficiency of a recently described bioabsorbable matrix as a guided tissue regeneration membrane. This matrix was prepared from an original reaction between elastin and fibrin monomers and is now extensively used in several domains of surgery. The study group was composed of 26 patients, with a total of 35 lesions (22 intrabony defects, 8 Class II furcations and 5 Class III furcations) presenting moderate to advanced adult periodontitis. After initial therapy, measurements were made with a calibrated periodontal probe. Probing depth (PD) and gingival margin location (GM) measurements were taken twice: immediately before surgery and after 6 months before re-entry. Clinical attachment level (CAL), vertical osseous level (VOL) and alveolar crest location (AC) measurements were taken during surgery and after 6 months with re-entry procedures for all the patients. Color change of the gingival margin was only observed in 4 defects and device exposure occurred in the proportion of 2 out of the 35 defects. No foreign body reaction was observed in any case. At the intrabony defects mean PD reduction was 5 mm (P < 0.001), and mean gain of CAL was 4 mm (P < 0.001). Mean VOL was 4.3 mm (P < 0.001), mean gingival recession was 0.9 mm (P < 0.05) and mean AC was 0.2 mm (NS). At the Class II furcation defects the mean PD reduction was 4.5 mm (P < 0.001), mean gain CAL vertical was 3.2 mm and CAL horizontal was 4.5 mm (P < 0.001). Gingival recession averaged 1 mm (NS). A complete closure was observed in 2 out of the 8 defects. At the Class III furcation defects the mean PD reduction was 3.6 mm (P < 0.05) and mean CAL-V gain was 1.5 mm (P < 0.02). However the 5 sites showed no horizontal attachment gain and none were unchanged. A very low gingival recession, gingival reaction, crestal bone loss, and device exposure occurred during this study. This preliminary study suggests that the use of a biosynthetic barrier may have

  15. Preclinical evaluation of a novel abluminal surface coated sirolimus eluting stent with biodegradable polymer matrix

    PubMed Central

    Doshi, Manish; Galloni, Marco; Vignolini, Christina; Vyas, Ashwin; Chevli, Bhavesh; Sheiban, Imad

    2015-01-01

    Background Second generation of drug eluting stents (DES) has attempted to improve safety using abluminal sirolimus drug delivery with biodegradable polymers matrix. The present preclinical study was designed to investigate the safety and efficacy profile of Abluminus™ stents (SES). This is a new coronary stent with sirolimus and biodegradable polymer matrix coated on abluminal stent and balloon surface. Methods SES were compared with two controls: bare metal stent (BMS) and BMS + polymer coated stents (PC). All devices (40 stents) were implanted in porcine coronary arteries with primary endpoint of endothelialization at 7 days and subsequent histological and morphometric evaluations at 7, 30 and 90 days. Results Early endothelialization at seven days was complete in all stents. Histology at 30 days revealed minimum inflammation in all groups and increased at 90 days in PC group while it was absent at 180 days. Thirty day morphometry showed significantly reduction of neointimal area in Abluminus™ (SES 0.96±0.48 mm2; BMS 1.83±0.34 mm2; PC 1.76±0.55 mm2; P<0.05); after 90 days neointimal area was 1.10±0.54 mm2 for SES; 1.92±0.36 mm2 for BMS; and 1.94±0.48 mm2 for PC; P<0.05). Neointimal thickness at 30 and 90 days respectively was 0.15±0.07 and 0.18±0.10 mm for SES, 0.57±0.08 and 0.61±0.09 mm for BMS and 0.52±0.09 and 0.59±0.08 mm, P<0.001 for PC group. Conclusions The most significant experimental evidence appears to be earlier endothelialization at 7 days for SES which led to safety of the device. Efficacy of the device was also observed by a reduced neointimal thickness and minimized inflammatory score at all follow-ups. Termination of antiplatelet at 30 days has not shown any further complications. Polymer thickness was almost in negligible amount at 180 days with no inflammation. PMID:26331109

  16. Photons Revisited

    NASA Astrophysics Data System (ADS)

    Batic, Matej; Begalli, Marcia; Han, Min Cheol; Hauf, Steffen; Hoff, Gabriela; Kim, Chan Hyeong; Kim, Han Sung; Grazia Pia, Maria; Saracco, Paolo; Weidenspointner, Georg

    2014-06-01

    A systematic review of methods and data for the Monte Carlo simulation of photon interactions is in progress: it concerns a wide set of theoretical modeling approaches and data libraries available for this purpose. Models and data libraries are assessed quantitatively with respect to an extensive collection of experimental measurements documented in the literature to determine their accuracy; this evaluation exploits rigorous statistical analysis methods. The computational performance of the associated modeling algorithms is evaluated as well. An overview of the assessment of photon interaction models and results of the experimental validation are presented.

  17. Automated evaluation of matrix elements between contracted wavefunctions: A Mathematica version of the FRODO program

    NASA Astrophysics Data System (ADS)

    Angeli, C.; Cimiraglia, R.

    2013-02-01

    A symbolic program performing the Formal Reduction of Density Operators (FRODO), formerly developed in the MuPAD computer algebra system with the purpose of evaluating the matrix elements of the electronic Hamiltonian between internally contracted functions in a complete active space (CAS) scheme, has been rewritten in Mathematica. New version : A program summaryProgram title: FRODO Catalogue identifier: ADV Y _v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVY_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 3878 No. of bytes in distributed program, including test data, etc.: 170729 Distribution format: tar.gz Programming language: Mathematica Computer: Any computer on which the Mathematica computer algebra system can be installed Operating system: Linux Classification: 5 Catalogue identifier of previous version: ADV Y _v1_0 Journal reference of previous version: Comput. Phys. Comm. 171(2005)63 Does the new version supersede the previous version?: No Nature of problem. In order to improve on the CAS-SCF wavefunction one can resort to multireference perturbation theory or configuration interaction based on internally contracted functions (ICFs) which are obtained by application of the excitation operators to the reference CAS-SCF wavefunction. The previous formulation of such matrix elements in the MuPAD computer algebra system, has been rewritten using Mathematica. Solution method: The method adopted consists in successively eliminating all occurrences of inactive orbital indices (core and virtual) from the products of excitation operators which appear in the definition of the ICFs and in the electronic Hamiltonian expressed in the second quantization formalism. Reasons for new version: Some years ago we published in this journal a couple of papers [1, 2

  18. Automated evaluation of matrix elements between contracted wavefunctions: A Mathematica version of the FRODO program

    NASA Astrophysics Data System (ADS)

    Angeli, C.; Cimiraglia, R.

    2013-02-01

    A symbolic program performing the Formal Reduction of Density Operators (FRODO), formerly developed in the MuPAD computer algebra system with the purpose of evaluating the matrix elements of the electronic Hamiltonian between internally contracted functions in a complete active space (CAS) scheme, has been rewritten in Mathematica. New version : A program summaryProgram title: FRODO Catalogue identifier: ADV Y _v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVY_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 3878 No. of bytes in distributed program, including test data, etc.: 170729 Distribution format: tar.gz Programming language: Mathematica Computer: Any computer on which the Mathematica computer algebra system can be installed Operating system: Linux Classification: 5 Catalogue identifier of previous version: ADV Y _v1_0 Journal reference of previous version: Comput. Phys. Comm. 171(2005)63 Does the new version supersede the previous version?: No Nature of problem. In order to improve on the CAS-SCF wavefunction one can resort to multireference perturbation theory or configuration interaction based on internally contracted functions (ICFs) which are obtained by application of the excitation operators to the reference CAS-SCF wavefunction. The previous formulation of such matrix elements in the MuPAD computer algebra system, has been rewritten using Mathematica. Solution method: The method adopted consists in successively eliminating all occurrences of inactive orbital indices (core and virtual) from the products of excitation operators which appear in the definition of the ICFs and in the electronic Hamiltonian expressed in the second quantization formalism. Reasons for new version: Some years ago we published in this journal a couple of papers [1, 2

  19. Evaluation of roll compaction as a preparation method for hydroxypropyl cellulose-based matrix tablets

    PubMed Central

    Jeon, Imjak; Gilli, Tiziana; Betz, Gabriele

    2011-01-01

    Roll compaction was applied for the preparation of hydroxypropyl cellulose (HPC)-based sustained-release matrix tablets. Matrix tablets made via roll compaction exhibited higher dosage uniformity and faster drug release than direct-compacted tablets. HPC viscosity grade, roll pressure, and milling speed affected tablet properties significantly. Roll compaction seems to be an adequate granulation method for the preparation of HPC-based matrix tablets due to the simplicity of the process, less handling difficulty from HPC tackiness as well as easier particle size targeting. Selecting the optimum ratio of plastic excipients and the particle size of starting materials can however be critical issues in this method. PMID:21687348

  20. Evaluation of roll compaction as a preparation method for hydroxypropyl cellulose-based matrix tablets.

    PubMed

    Jeon, Imjak; Gilli, Tiziana; Betz, Gabriele

    2011-04-01

    Roll compaction was applied for the preparation of hydroxypropyl cellulose (HPC)-based sustained-release matrix tablets. Matrix tablets made via roll compaction exhibited higher dosage uniformity and faster drug release than direct-compacted tablets. HPC viscosity grade, roll pressure, and milling speed affected tablet properties significantly. Roll compaction seems to be an adequate granulation method for the preparation of HPC-based matrix tablets due to the simplicity of the process, less handling difficulty from HPC tackiness as well as easier particle size targeting. Selecting the optimum ratio of plastic excipients and the particle size of starting materials can however be critical issues in this method. PMID:21687348

  1. Rapid HPLC analysis of amino acids and biogenic amines in wines during fermentation and evaluation of matrix effect.

    PubMed

    Wang, Ya-Qin; Ye, Dong-Qing; Zhu, Bao-Qing; Wu, Guang-Feng; Duan, Chang-Qing

    2014-11-15

    A rapid HPLC method has been developed for the simultaneous determination of 23 amino acids, 10 biogenic amines and the ammonium ion in wine. Samples were pre-column derivatised with diethyl ethoxymethylenemalonate and separated using reversed-phase HPLC within 30 min. The matrix effect was evaluated when measuring samples taken from different stages of fermentation. Most compounds showed no obvious matrix effect, whereas proline, ethanolamine and spermine had remarkably different responses to variable concentrations of sugar. High concentrations of sugar affected the pH of the derivatisation reaction system; proline, ethanolamine and spermine derivatives were sensitive to this effect. Matrix-matched calibration was used for the quantification of these compounds. Validation of the method showed that it was accurate, reproducible and efficient for the simultaneous determination of amino acids and biogenic amines in wines during fermentation. As a specific application of the method, red wine samples taken from different stages of fermentation were analysed. PMID:24912689

  2. Evaluation of Topical Hesperetin Matrix film for Back-of-the-Eye Delivery

    PubMed Central

    Adelli, Goutham R.; Hingorani, Tushar; Punyamurthula, Nagendra; Balguri, Sai Prachetan; Majumdar, Soumyajit

    2015-01-01

    Purpose The goal of the present study is to develop a poly (ethylene oxide) N10 (PEO N10) based melt-cast matrix system for efficient and prolonged delivery of hesperetin (HT), a promising bioflavonoid, to the posterior segment of the eye through the topical route. Methods HT film was prepared by melt-cast method using PEO N10 and cut into 4 mm × 2 mm segments, each weighing 8 mg. This film was evaluated with respect to in vitro release rates and also transmembrane delivery across Spectra/Por® membrane (MWCO: 10000 Daltons) and isolated rabbit corneas. Ocular tissue concentrations were also determined post application of the film in ex vivo and in vivo models. Results HT release from the film was determined to be about 95.3 % within 2 h. In vitro transcorneal flux was observed to be 0.58 ± 0.05 μg/min/cm2 across the isolated rabbit cornea. High levels of HT were detected in the retina-choroid (RC) and vitreous humor (VH) in the ex vivo model following topical application of the film. Significant levels of HT were observed in both anterior and posterior segment ocular tissues 1h post topical application of the 10 and 20 %w/w HT films on the rabbit eye. Moreover, HT was detected in the VH and RC even after 6h following topical application of the film in vivo. Conclusion The results from this study suggest that the melt-cast films can serve as a viable platform for sustained topical delivery of bioflavonoids, and other therapeutic agents, into the back-of-the eye tissues. PMID:25728824

  3. Evaluation of two fast and easy methods for pesticide residue analysis in fatty food matrixes.

    PubMed

    Lehotay, Steven J; Mastovská, Katerina; Yun, Seon Jong

    2005-01-01

    Two rapid methods of sample preparation and analysis of fatty foods (e.g., milk, eggs, and avocado) were evaluated and compared for 32 pesticide residues representing a wide range of physicochemical properties. One method, dubbed the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residue analysis, entailed extraction of 15 g sample with 15 mL acetonitrile (MeCN) containing 1% acetic acid followed by addition of 6 g anhydrous magnesium sulfate and 1.5 g sodium acetate. After centrifugation, 1 mL of the buffered MeCN extract underwent a cleanup step (in a technique known as dispersive solid-phase extraction) using 50 mg each of C18 and primary secondary amine sorbents plus 150 mg MgSO4. The second method incorporated a form of matrix solid-phase dispersion (MSPD), in which 0.5 g sample plus 2 g C18 and 2 g anhydrous sodium sulfate was mixed in a mortar and pestle and added above a 2 g Florisil column on a vacuum manifold. Then, 5 x 2 mL MeCN was used to elute the pesticide analytes from the sample into a collection tube, and the extract was concentrated to 0.5 mL by evaporation. Extracts in both methods were analyzed concurrently by gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry. The recoveries of semi-polar and polar pesticides were typically 100% in both methods (except that basic pesticides, such as thiabendazole and imazalil, were not recovered in the MSPD method), but recovery of nonpolar pesticides decreased as fat content of the sample increased. This trend was more pronounced in the QuEChERS method, in which case the most lipophilic analyte tested, hexachlorobenzene, gave 27 +/- 1% recovery (n=6) in avocado (15% fat) with a<10 ng/g limit of quantitation. PMID:15859091

  4. Brezinaite Revisited

    NASA Astrophysics Data System (ADS)

    Davis, D. E.

    1993-07-01

    Brezinaite Data: Idealized formula: (Cr^2+Cr^3+)(sub)3S(sub)4, metal: sulphur ratio=0.76 - 0.79, structure: defect NiAs-type, symmetry: monoclinic I 2/m, Beta = 91 degrees 32'. As part of a research program in Copenhagen and at the Smithsonian Institution involving sulphides in selected irons, the mineral brezinaite was, quite surprisingly, found to be present in several of the sections studied. Brezinaite is a rare meteoritic sulphide, previously only reported in two Anom. irons; Tucson [1] and New Baltimore [2] , a list that can now be extended to include, as a minimum, the following meteorites: Type IIIA; Costilla Peak, Kalkaska and Murfreesboro. Type IVA; Jamestown, La Grange and Western Arkansas. Anom. or type IIIF; Saint Genevieve County. A thin section examination by reflected light alone will not always be enough to identify the mineral with sufficient accuracy, and it is, therefore, only meteorites in which brezinaite has been confirmed by microprobe analysis that are mentioned above. With the exception of Tucson, where brezinaite is frequently found as anhedral grains contiguous to silicate inclusions, its typical occurrence is either in or along sub-boundaries of the kamacite bands, or occasionally within comb- structured plessite fields. Brezinaite appears most commonly as minute (5-200 micrometers) anhedral-subhedral greyish colored grains, occasionally with a partial rim of schreibersite (eg., Murfreesboro), that occur freely scattered throughout the metal matrix. With the notable exception of troilite aggregates, in which brezinaite does not occur, its appearance and occurrence coincide with the common mineral daubreelite (VH~400 and R% = 37- 40). The difficulty in distinguishing between these two minerals has been a source of confusion. The present study shows that the two minerals both occur as isolated grains and in the immediate vicinity of each other. The intimate relationship between the two minerals is especially clear in Costilla Peak where

  5. Mere Exposure Revisited: The Influence of Growth versus Security Cues on Evaluations of Novel and Familiar Stimuli

    ERIC Educational Resources Information Center

    Gillebaart, Marleen; Forster, Jens; Rotteveel, Mark

    2012-01-01

    Combining regulatory focus theory (Higgins, 1997) and novelty categorization theory (Forster, Marguc, & Gillebaart, 2010), we predicted that novel stimuli would be more positively evaluated when focused on growth as compared with security and that familiar stimuli would be more negatively evaluated when focused on growth as compared with security.…

  6. Formulation and Evaluation of Once Daily Minocycline Hydrochloride Extended Release Matrix Tablets

    PubMed Central

    Keny, R. V.; Mankame, S. A.; Lourenco, C. F.

    2009-01-01

    The present study was aimed to develop once daily extended release matrix tablets of minocycline hydrochloride, using hydroxypropylmethylcellulose either alone or in combination with ethyl cellulose as the matrix material in different proportions. The formulated tablets were also compared with a marketed product. The results of the dissolution study indicate that formulations FC-IV, FC-V and FC-VI showed maximum drug release upto 24 h, whereas the marketed product was found to extend the release only up to 14 h. Incase of formulations containing combination of hydroxypropylmethylcellulose and ethyl cellulose (FC-I to FC-IX), the release of the drug was found to be dependent on the relative proportions of hydroxypropylmethylcellulose and ethyl cellulose used in the tablet matrix. Mathematical treatment of the in vitro drug release data suggests that, all the formulations best fitted into first order release kinetics. Drug release from the matrix occurred by combination of two mechanisms, diffusion of drug from tablet matrix and erosion of tablet surface, which was reflected from Higuchi's model and Erosion plot. PMID:20490297

  7. Formulation and evaluation of ethylene-vinyl acetate copolymer matrix patches containing formoterol fumarate.

    PubMed

    Kakubari, Ikuhiro; Shinkai, Norihiro; Kawakami, Junji; Uruno, Akemi; Takayasu, Toshiyuki; Yamauchi, Hitoshi; Takayama, Satoshi; Takayama, Kozo

    2006-03-01

    The skin permeability and stability of formoterol fumarate (FF) in matrix patches containing l-menthol as an enhancer and N-methyl-2-pyrrolidone (NMP) as the solvent were investigated. Using a total of 28 matrix patches having a similar composition, containing ethylene-vinyl acetate (EVA) as the forming polymer and hydrogenated rosin glycerol ester (Ester Gum H) as the adhesive, the skin permeation of FF was found to increase with increasing l-menthol and NMP contents. FF in the matrix patches containing NMP in the range of 4.8-7.2% was stable, but stability decreased at higher values. With a standard matrix patch containing FF, the Cmax and AUC(0-24) values were found to be 1.93 ng/ml after 4 h percutaneous application to rats and 25.6 ng x h/ml. The bioavailability after percutaneous exposure was equivalent to 15.2% of the AUC(0-24) after intravenous administration. Percutaneous application proved efficacious with regard to control of simulated asthma at dose levels lower than those with which side effects occurred. Thus an optimized matrix patch containing FF was prepared with potential advantages for control of asthma. PMID:16508156

  8. Preparation and evaluation of sustained release calcium alginate beads and matrix tablets of acetazolamide.

    PubMed

    Barzegar-Jalali, M; Hanaee, J; Omidi, Y; Ghanbarzadeh, S; Ziaee, S; Bairami-Atashgah, R; Adibkia, K

    2013-02-01

    The aim of this study was to develop sustained release dosage forms of acetazolamide (ACZ) preparing its calcium alginate beads and matrix tablets. ACZ was incorporated into calcium alginate beads using microencapsulation method. Two methods were applied to prolong ACZ release rate. In the first method, the drug was incorporated into calcium alginate beads either alone or with various polymers in internal phase. The second method involved the preparation of matrix tablet from the beads benefiting direct compression method with or without various polymers in external phase. The release rate of these prepared formulations and an innovator's sustained-release capsule (Diamox®) were assessed. In-vitro dissolution studies revealed that the matrix tablets prepared by the second method containing NaCMC could sustain ACZ release properly and the drug released until 9 h. It was also found that several parameters such as concentration of sodium alginate, calcium chloride and ACZ; type and concentration of polymers; syringe needle size as well as distance between needle tip and surface of the calcium chloride could affect the properties of beads, matrix tablets and subsequently release profile. Preparation of polymer free beads, incorporation of polymers in internal phase of the beads and direct compression of the beads did not give sustained release property. Whereas, incorporation of NaCMC in the external phase of the beads in matrix tablets or in combination with alginate powder in directly compressed conventional tablets could produce dosage form with sustained release property similar to reference formulation. PMID:23447074

  9. STATISTICAL EVALUATION OF PROCESSING DATA FROM THE RH RU HG MATRIX STUDY

    SciTech Connect

    Koopman, D

    2009-04-17

    An evaluation of the statistical significance of Rh, Ru, and Hg on DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle catalytic hydrogen generation and process chemistry was conducted by the Savannah River National Laboratory (SRNL) using a full-factorial experimental design. This test design can identify significant interactions between these three species in addition to individual effects. Statistical modeling of data from the Rh-Ru-Hg matrix study has been completed. Preliminary data and conclusions were given in an earlier report. This final report concludes the work on the Rh-Ru-Hg matrix study. Modeling results are summarized below. Rhodium was found to: Promote increased total hydrogen mass; Promote an increase in the maximum hydrogen generation rate; Promote an increase in the hydrogen generation rate shortly after acid addition; Shorten the elapsed time between acid addition and the maximum hydrogen generation rate; Increase formate loss; Inhibit NO{sub 2} and total NO{sub x} off-gas species formation; and Reduce nitrite-to-nitrate conversion. Ruthenium was found to: Promote increased total hydrogen mass; Promote an increase in the maximum hydrogen generation rate; Promote an increase in the hydrogen generation rate in the second half of the SRAT cycle; Promote an increase in total CO{sub 2} generated; Increase formate loss; Promote NO{sub 2} and total NO{sub x} off-gas species formation; and Reduce nitrite-to-nitrate conversion. Mercury was found to: Inhibit total hydrogen mass produced; Promote an increase in total CO{sub 2} generated; Promote NO{sub 2} off-gas species formation; and Inhibit total NO{sub x} off-gas species formation. Results confirmed qualitative observations that Rh was activating before Ru for hydrogen generation. An interaction between Rh and Ru was present in the model for the total hydrogen generated during the SRAT, perhaps because the total combined contributions from two separate episodes of hydrogen generation. The first

  10. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SERVICES (CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES General... subject to user fees unless otherwise exempted. Revisit survey means a survey performed with respect to a... substantiated complaint survey and that is designed to evaluate the extent to which...

  11. Formulation and evaluation of mixed matrix gastro-retentive drug delivery for famotidine

    PubMed Central

    Patel, Dasharath M; Patel, Mehul J; Patel, Ankit N; Patel, Chhagan N

    2011-01-01

    Introduction: Present investigation describes an influence of ratio of Gelucire 43/01(hydrophobic) to hydroxypropyl methylcellulose K4M (HPMC K4M) (hydrophilic) and different fillers on release of famotidine from gastro-retentive tablets using 32 full factorial design. Ratio of Gelucire 43/01 to HPMC K4M (X1) and the type of filler (X2) were selected as independent variables while buoyancy lag time (BLT), drug release at 1h (Q1), 6h (Q6), and the 12h (Q12) were selected as dependent variables. Materials and Methods: Gastro-retentive tablets of famotidine were prepared by a solvent free melt granulation technique using Gelucire 43/01 as a hydrophobic meltable binder. HPMC K4M and sodium bicarbonate were used as matrixing agent and gas-generating agent, respectively. Prepared tablets were evaluated for in vitro dissolution, in vitro buoyancy, friability, hardness, drug content and weight variation. Dissolution data were fitted to various models to ascertain kinetics of drug release. The data were analyzed using regression analysis and analysis of variance. Results: All formulations (F1-F9) showed floating within 3min and had total floating time of more than 12h. It was observed that a type of filler and the ratio of Gelucire 43/01 to HPMC K4M had significant influence on buoyancy lag time (P = 0.037) and Q6 (P = 0.011), respectively without significant influence on Q1 and Q12. Conclusion: Formulation F5 was selected as an optimum formulation as it showed more similarity in dissolution profile with theoretical profile (Similarity factor, f2 = 83.01). The dissolution of batch F5 can be described by zero order kinetics (r2 = 0.9914) with anomalous (non-Fickian) diffusion as a release mechanism (n = 0.559). The difference observed in in vitro release profile after temperature sensitivity study at 40°C for 1 month was insignificant. PMID:23071951

  12. The use of immunohistochemistry in the evaluation of the nail matrix in biopsies of ingrown toenails.

    PubMed

    Fernandez-Flores, A; Martínez-Nova, A

    2013-01-01

    The success of surgical approaches to ingrown toenails depends on the extraction (either partial or total) of the nail matrix. The identification of the nail matrix in specimens taken from ingrown toenails is not always easy because of the fragmentation of the biopsies, difficulties in matrix orientations and the heavy inflammatory infiltrate. In biopsies taken from polydactyly surgeries, the matrix shows a peculiar pattern of expression of the CD10 and CD34 markers that differs from the one shown by the lateral nail fold. We investigated whether such a pattern was also found in biopsies from ingrown toenails, which can be greatly distorted through inflammation and fibrosis. We examined 15 biopsies from cases of ingrown toenails at different clinical stages. We performed routine Hematoxylin-Eosin studies, as well as immunohistochemical studies with CD10, CD34, HMB-45 and Melan-A. The morphologic changes in all cases were typical of those found in ingrown toenails and their intensities correlated with the clinical stages. Matrical keratinization was identified in all of the biopsies. Morphologic features that are compatible with the lateral nail fold were also seen in seven of the 15 biopsies. In five cases, an intermediate area of transition between matrix and lateral nail folds was heavily distorted by inflammatory changes. Melanocytic markers showed scattered intra-epidermal cells in all but one case. HMB-45 and Melan-A were equally good in demonstrating the melanocytic population. We concluded that the expression of CD10 and CD34 in cases of ingrown toenails is preserved and it follows the pattern described in nails from polydactyly. Therefore, both markers can be useful in fragmented specimens taken from surgeries for ingrown toenails, in order to confirm the removal of the nail matrix. PMID:23771067

  13. A large-scale evaluation of Risk Matrix 2000 in Scotland.

    PubMed

    Grubin, Don

    2011-12-01

    Risk Matrix 2000 is a statistically derived risk-assessment instrument for use with convicted male sex offenders. It is a core element of the sex offender risk assessments carried out in England, Wales, and Scotland. This study examines its validity in a large cohort of sex offenders released from Scottish prisons. It compares 5-year outcomes with findings from the original Risk Matrix validity sample (a 1979 cohort of sex offenders in England and Wales). The instrument had moderate predictive validity and performed in a similar manner in the two studies in spite of different underlying base rates of reconviction. PMID:21965466

  14. Toxicological evaluation of Fusarium verticillioides culture material nixtamalized in the presence and absence of corn matrix.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cooking-steeping corn in alkaline water (nixtamalization) reduces the amount of detectable fumonisin B1 (FB1) in masa and tortilla products. However, reductions might be overestimated if FB1 reacts with the corn matrix to form undetectable reaction products. The purpose of this study was to investig...

  15. TASK-BASED EXPOSURE MATRIX TOWARD EVALUATING AND IDENTIFYING OCCUPATIONAL EXPOSURE TO ENGINEERED CARBONACEOUS NANOMATERIALS

    EPA Science Inventory

    It is expected that the findings from this study will contribute to human exposure estimation during the product lifecycle analysis of carbon nanotubes and nanofibers. In addition, the task exposure matrix will provide important background information for the design of future ...

  16. Toxicological Evaluation of Fusarium verticillioides Culture Material Nixtamalized in the Presence and Absence of Corn Matrix

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cooking-steeping corn in alkaline water (nixtamalization) reduces the amount of detectable fumonisin B1 (FB1) in masa and tortilla products. However, reductions might be overestimated if FB1 reacts with the corn matrix to form undetectable reaction products. The purpose of this study was to investig...

  17. Evaluation of Non-Watertight Dural Reconstruction with Collagen Matrix Onlay Graft in Posterior Fossa Surgery

    PubMed Central

    Lobo, Bjorn; Lim, Joshua; Sade, Burak; Oya, Soichi; Lee, Joung H.

    2016-01-01

    Objective Many surgeons advocate for watertight dural reconstruction after posterior fossa surgery given the significant risk of cerebrospinal fluid (CSF) leak. Little evidence exists for posterior fossa dural reconstruction utilizing monolayer collagen matrix onlay graft in a non-watertight fashion. Our objective was to report the results of using collagen matrix in a non-watertight fashion for posterior fossa dural reconstruction. Methods We conducted a retrospective review of operations performed by the senior author from 2004–2011 identified collagen matrix (DuraGen) use in 84 posterior fossa operations. Wound complications such as CSF leak, infection, pseudomeningocele, and aseptic meningitis were noted. Fisher's exact test was performed to assess risk factor association with specific complications. Results Incisional CSF leak rate was 8.3% and non-incisional CSF leak rate was 3.6%. Incidence of aseptic meningitis was 7.1% and all cases resolved with steroids alone. Incidence of palpable and symptomatic pseudomeningocele in follow-up was 10.7% and 3.6% respectively. Postoperative infection rate was 4.8%. Previous surgery was associated with pseudomeningocele development (p<0.05). Conclusion When primary dural closure after posterior fossa surgery is undesirable or not feasible, non-watertight dural reconstruction with collagen matrix resulted in incisional CSF leak in 8.3%. Incidence of pseudomeningocele, aseptic meningitis, and wound infection were within acceptable range. Data from this study may be used to compare alternative methods of dural reconstruction in posterior fossa surgery. PMID:26885286

  18. Illustrative case using the RISK21 roadmap and matrix: prioritization for evaluation of chemicals found in drinking water

    PubMed Central

    Wolf, Douglas C.; Bachman, Ammie; Barrett, Gordon; Bellin, Cheryl; Goodman, Jay I.; Jensen, Elke; Moretto, Angelo; McMullin, Tami; Pastoor, Timothy P.; Schoeny, Rita; Slezak, Brian; Wend, Korinna; Embry, Michelle R.

    2016-01-01

    ABSTRACT The HESI-led RISK21 effort has developed a framework supporting the use of twenty-first century technology in obtaining and using information for chemical risk assessment. This framework represents a problem formulation-based, exposure-driven, tiered data acquisition approach that leads to an informed decision on human health safety to be made when sufficient evidence is available. It provides a transparent and consistent approach to evaluate information in order to maximize the ability of assessments to inform decisions and to optimize the use of resources. To demonstrate the application of the framework’s roadmap and matrix, this case study evaluates a large number of chemicals that could be present in drinking water. The focus is to prioritize which of these should be considered for human health risk as individual contaminants. The example evaluates 20 potential drinking water contaminants, using the tiered RISK21 approach in combination with graphical representation of information at each step, using the RISK21 matrix. Utilizing the framework, 11 of the 20 chemicals were assigned low priority based on available exposure data alone, which demonstrated that exposure was extremely low. The remaining nine chemicals were further evaluated, using refined estimates of toxicity based on readily available data, with three deemed high priority for further evaluation. In the present case study, it was determined that the greatest value of additional information would be from improved exposure models and not from additional hazard characterization. PMID:26451723

  19. Illustrative case using the RISK21 roadmap and matrix: prioritization for evaluation of chemicals found in drinking water.

    PubMed

    Wolf, Douglas C; Bachman, Ammie; Barrett, Gordon; Bellin, Cheryl; Goodman, Jay I; Jensen, Elke; Moretto, Angelo; McMullin, Tami; Pastoor, Timothy P; Schoeny, Rita; Slezak, Brian; Wend, Korinna; Embry, Michelle R

    2016-01-01

    The HESI-led RISK21 effort has developed a framework supporting the use of twenty-first century technology in obtaining and using information for chemical risk assessment. This framework represents a problem formulation-based, exposure-driven, tiered data acquisition approach that leads to an informed decision on human health safety to be made when sufficient evidence is available. It provides a transparent and consistent approach to evaluate information in order to maximize the ability of assessments to inform decisions and to optimize the use of resources. To demonstrate the application of the framework's roadmap and matrix, this case study evaluates a large number of chemicals that could be present in drinking water. The focus is to prioritize which of these should be considered for human health risk as individual contaminants. The example evaluates 20 potential drinking water contaminants, using the tiered RISK21 approach in combination with graphical representation of information at each step, using the RISK21 matrix. Utilizing the framework, 11 of the 20 chemicals were assigned low priority based on available exposure data alone, which demonstrated that exposure was extremely low. The remaining nine chemicals were further evaluated, using refined estimates of toxicity based on readily available data, with three deemed high priority for further evaluation. In the present case study, it was determined that the greatest value of additional information would be from improved exposure models and not from additional hazard characterization. PMID:26451723

  20. Revisiting Insights from Three Mile Island Unit 2 Postaccident Examinations and Evaluations in View of the Fukushima Daiichi Accident

    SciTech Connect

    Rempe, Joy; Farmer, Mitchell; Corradini, Michael; Ott, Larry; Gauntt, Randall; Powers, Dana

    2012-11-01

    The Three Mile Island Unit 2 (TMI-2) accident, which occurred on March 28, 1979, led industry and regulators to enhance strategies to protect against severe accidents in commercial nuclear power plants. Investigations in the years after the accident concluded that at least 45% of the core had melted and that nearly 19 tonnes of the core material had relocated to the lower head. Postaccident examinations indicate that about half of that material formed a solid layer near the lower head and above it was a layer of fragmented rubble. As discussed in this paper, numerous insights related to pressurized water reactor accident progression were gained from postaccident evaluations of debris, reactor pressure vessel (RPV) specimens, and nozzles taken from the RPV. In addition, information gleaned from TMI-2 specimen evaluations and available data from plant instrumentation were used to improve severe accident simulation models that form the technical basis for reactor safety evaluations. Finally, the TMI-2 accident led the nuclear community to dedicate considerable effort toward understanding severe accident phenomenology as well as the potential for containment failure. Because available data suggest that significant amounts of fuel heated to temperatures near melting, the events at Fukushima Daiichi Units 1, 2, and 3 offer an unexpected opportunity to gain similar understanding about boiling water reactor accident progression. To increase the international benefit from such an endeavor, we recommend that an international effort be initiated to (a) prioritize data needs; (b) identify techniques, samples, and sample evaluations needed to address each information need; and (c) help finance acquisition of the required data and conduct of the analyses.

  1. Formulation and in vivo evaluation of diclofenac sodium sustained release matrix tablet: effect of compression force.

    PubMed

    Taha, Ehab Ibrahim; Shazly, Gamal Abdel-Ghany; Harisa, Gamaleldin Ibrahim; Barakat, Nahla Sedik; Al-Enazi, Fouza Kayem; Elbagory, Ibrahim Mostafa

    2015-03-01

    In the present study, Diclofenac Sodium (DS) matrix tablets were prepared by direct compression method under different compression forces (5, 10, 15 and 20 KN), using ethylcellulose as matrix forming material. The produced tablets were characterized on the foundation of satisfactory tablet properties such as hardness, friability, drug content, weight variations and in vitro drug release rate. Differential scanning calorimetry (DSC), Fourier Transform Infrared (FT-IR) spectroscopy and X-ray diffraction have been used to investigate any incompatibilities of the tablet's ingredients. Additionally, in vivo bioavailability has been investigated on beagle dogs. Data obtained revealed that, upon increasing compression force the in vitro drug release was sustained and the T(max) value was four hours (for formulations compressed at 15 and 20 kN) compared to the conventional voltarine(®) 50 tablets (T(max) value of 2 hours). PMID:25730790

  2. Development and Clinical Evaluation of MatrixMANDIBLE Subcondylar Plates System (Synthes).

    PubMed

    Cortelazzi, Roberto; Altacera, Mario; Turco, Monica; Antonicelli, Viviana; De Benedittis, Michele

    2015-06-01

    In this article, authors report the different steps of development and clinical validation of MatrixMANDIBLE Subcondylar Plates (Synthes, Soletta, Switzerland), a specialized osteosynthesis system developed by Synthes during the past 4 years. Between 2009 and 2013, a total of 62 patients were treated for subcondylar and condylar neck fractures via a preauricular or retromandibular/transparotid approach. The MatrixMANDIBLE Subcondylar Plates System consists of a Trapezoidal Plate, a three-dimensional (3D) 4-hole 1.0-mm plate for smaller fracture areas, the Lambda Plate, a 7-hole 1.0-mm linear plate which mimics the two miniplates technique, and the Strut Plate, a 3D 1.0-mm plate with great versatility of employment. All devices satisfy the principles of a functionally stable osteosynthesis as stated by Champy et al. None of the plates broke and no macroscopic condylar displacement was noted on radiological follow-up. Clinical and functional parameters assessed at 6 months postoperative (mandibular range of motion, pain, dental occlusion) were almost restored. MatrixMANDIBLE Subcondylar Plates System (Synthes) has proved to provide sufficient mechanical stiffness and anatomically accurate fracture reduction to avoid major postoperative drawbacks of subcondylar and condylar neck fractures. PMID:26000078

  3. Development and Clinical Evaluation of MatrixMANDIBLE Subcondylar Plates System (Synthes)

    PubMed Central

    Cortelazzi, Roberto; Altacera, Mario; Turco, Monica; Antonicelli, Viviana; De Benedittis, Michele

    2014-01-01

    In this article, authors report the different steps of development and clinical validation of MatrixMANDIBLE Subcondylar Plates (Synthes, Soletta, Switzerland), a specialized osteosynthesis system developed by Synthes during the past 4 years. Between 2009 and 2013, a total of 62 patients were treated for subcondylar and condylar neck fractures via a preauricular or retromandibular/transparotid approach. The MatrixMANDIBLE Subcondylar Plates System consists of a Trapezoidal Plate, a three-dimensional (3D) 4-hole 1.0-mm plate for smaller fracture areas, the Lambda Plate, a 7-hole 1.0-mm linear plate which mimics the two miniplates technique, and the Strut Plate, a 3D 1.0-mm plate with great versatility of employment. All devices satisfy the principles of a functionally stable osteosynthesis as stated by Champy et al. None of the plates broke and no macroscopic condylar displacement was noted on radiological follow-up. Clinical and functional parameters assessed at 6 months postoperative (mandibular range of motion, pain, dental occlusion) were almost restored. MatrixMANDIBLE Subcondylar Plates System (Synthes) has proved to provide sufficient mechanical stiffness and anatomically accurate fracture reduction to avoid major postoperative drawbacks of subcondylar and condylar neck fractures. PMID:26000078

  4. Swedish Successful Schools Revisited

    ERIC Educational Resources Information Center

    Hoog, Jonas; Johansson, Olof; Olofsson, Anders

    2009-01-01

    Purpose: The purpose of this paper is to describe the results of a follow-up study of two Swedish schools in which, five years previously, the principals had been successful leaders. Had this success been maintained? Design/methodology/approach: Two schools were revisited to enable the authors to interview principals and teachers as well as…

  5. The Linguistic Repertoire Revisited

    ERIC Educational Resources Information Center

    Busch, Brigitta

    2012-01-01

    This article argues for the relevance of poststructuralist approaches to the notion of a linguistic repertoire and introduces the notion of language portraits as a basis for empirical study of the way in which speakers conceive and represent their heteroglossic repertoires. The first part of the article revisits Gumperz's notion of a linguistic…

  6. A Hydrostatic Paradox Revisited

    ERIC Educational Resources Information Center

    Ganci, Salvatore

    2012-01-01

    This paper revisits a well-known hydrostatic paradox, observed when turning upside down a glass partially filled with water and covered with a sheet of light material. The phenomenon is studied in its most general form by including the mass of the cover. A historical survey of this experiment shows that a common misunderstanding of the phenomenon…

  7. Revisiting Bioaccumulation Criteria

    EPA Science Inventory

    The objective of workgroup 5 was to revisit the B(ioaccumulation) criteria that are currently being used to identify POPs under the Stockholm Convention and PBTs under CEPA, TSCA, REACh and other programs. Despite the lack of a recognized definition for a B substance, we defined ...

  8. Colloquial Hebrew Imperatives Revisited

    ERIC Educational Resources Information Center

    Bolozky, Shmuel

    2009-01-01

    In revisiting Bolozky's [Bolozky, Shmuel, 1979. "On the new imperative in colloquial Hebrew." "Hebrew Annual Review" 3, 17-24] and Bat-El's [Bat-El, Outi, 2002. "True truncation in colloquial Hebrew imperatives." "Language" 78(4), 651-683] analyses of colloquial Hebrew imperatives, the article argues for restricting Imperative Truncation to the…

  9. Revisiting Curriculum Potential

    ERIC Educational Resources Information Center

    Deng, Zongyi

    2011-01-01

    This article analyzes the notion of curriculum potential by revisiting the ideas of Miriam Ben-Peretz and Joseph Schwab. Invoking the German "Didaktik" tradition and by way of a curriculum-making framework, the paper argues that interpreting curriculum materials for curriculum potential requires a careful analysis and unpacking of the meanings and…

  10. Anodic Polarization Curves Revisited

    ERIC Educational Resources Information Center

    Liu, Yue; Drew, Michael G. B.; Liu, Ying; Liu, Lin

    2013-01-01

    An experiment published in this "Journal" has been revisited and it is found that the curve pattern of the anodic polarization curve for iron repeats itself successively when the potential scan is repeated. It is surprising that this observation has not been reported previously in the literature because it immediately brings into…

  11. Revisiting the Rhetorical Curriculum

    ERIC Educational Resources Information Center

    Rutten, Kris; Soetaert, Ronald

    2012-01-01

    The aim of the special strand on "Revisiting the rhetorical curriculum" is to explore the educational potential of a new rhetorical perspective, specifically in relation to different traditions within educational and rhetorical studies. This implies that we do not only look at education "in" rhetoric, but that we position education also "as" a…

  12. Evaluating changes in matrix based, recovery-adjusted concentrations in paired data for pesticides in groundwater

    USGS Publications Warehouse

    Zimmerman, Tammy M.; Breen, Kevin J.

    2012-01-01

    Pesticide concentration data for waters from selected carbonate-rock aquifers in agricultural areas of Pennsylvania were collected in 1993–2009 for occurrence and distribution assessments. A set of 30 wells was visited once in 1993–1995 and again in 2008–2009 to assess concentration changes. The data include censored matched pairs (nondetections of a compound in one or both samples of a pair). A potentially improved approach for assessing concentration changes is presented where (i) concentrations are adjusted with models of matrix-spike recovery and (ii) area-wide temporal change is tested by use of the paired Prentice-Wilcoxon (PPW) statistical test. The PPW results for atrazine, simazine, metolachlor, prometon, and an atrazine degradate, deethylatrazine (DEA), are compared using recovery-adjusted and unadjusted concentrations. Results for adjusted compared with unadjusted concentrations in 2008–2009 compared with 1993–1995 were similar for atrazine and simazine (significant decrease; 95% confidence level) and metolachlor (no change) but differed for DEA (adjusted, decrease; unadjusted, increase) and prometon (adjusted, decrease; unadjusted, no change). The PPW results were different on recovery-adjusted compared with unadjusted concentrations. Not accounting for variability in recovery can mask a true change, misidentify a change when no true change exists, or assign a direction opposite of the true change in concentration that resulted from matrix influences on extraction and laboratory method performance. However, matrix-based models of recovery derived from a laboratory performance dataset from multiple studies for national assessment, as used herein, rather than time- and study-specific recoveries may introduce uncertainty in recovery adjustments for individual samples that should be considered in assessing change.

  13. Revisiting the “Golden Hour”: An Evaluation of Out-of-Hospital Time in Shock and Traumatic Brain Injury

    PubMed Central

    Newgard, Craig D.; Meier, Eric N.; Bulger, Eileen M.; Buick, Jason; Sheehan, Kellie; Lin, Steve; Minei, Joseph P.; Barnes-Mackey, Roxy A.; Brasel, Karen

    2015-01-01

    Study Objective We evaluated shock and traumatic brain injury (TBI) patients previously enrolled in an out-of-hospital clinical trial to test the association between out-of-hospital time and outcome. Methods This was a secondary analysis of shock and TBI patients ≥ 15 years enrolled in a Resuscitation Outcomes Consortium out-of-hospital clinical trial by 81 EMS agencies transporting to 46 Level I and II trauma centers in 11 sites (May 2006 through May 2009). Inclusion criteria were: SBP ≤ 70 mmHg or SBP 71 - 90 mmHg with heart rate ≥ 108 beats per minute (shock cohort) and Glasgow Coma Scale score ≤ 8 (TBI cohort); patients meeting both criteria were placed in the shock cohort. Primary outcomes were 28-day mortality (shock cohort) and 6-month Glasgow Outcome Scale - Extended (GOSE) ≤ 4 (TBI cohort). Results There were 778 patients in the shock cohort (26% 28-day mortality) and 1,239 patients in the TBI cohort (53% 6-month GOSE ≤ 4). Out-of-hospital time > 60 minutes was not associated with worse outcomes after accounting for important confounders in the shock cohort (adjusted odds ratio [aOR] 1.42, 95% CI 0.77-2.62) or TBI cohort (aOR 0.80, 95% CI 0.52-1.21). However, shock patients requiring early critical hospital resources and arriving > 60 minutes had higher 28-day mortality (aOR 2.37, 95% CI 1.05-5.37); this finding was not observed among a similar TBI subgroup. Conclusions Among out-of-hospital trauma patients meeting physiologic criteria for shock and TBI, there was no association between time and outcome. However, the subgroup of shock patients requiring early critical resources arriving after 60 minutes had higher mortality. PMID:25596960

  14. In vitro/in vivo evaluation of HPMC/alginate based extended-release matrix tablets of cefpodoxime proxetil.

    PubMed

    Mujtaba, Ali; Kohli, Kanchan

    2016-08-01

    The purpose of this research was to assessment of antimicrobial activity and in vitro/in vivo evaluation of cefpodoxime proxetil extended-release (ER) tablet for once daily administration. The tablets were prepared using combination of biodegradable polysaccharides including hydroxypropyl methylcellulose and sodium alginate as matrix material to achieve pH-independent ER release. The tablets were found within the permissible limits for various physicochemical parameters. The in vitro drug release showed that the drug was released over a period of 24h in a sustained release manner. The drug release followed Higuchi kinetics as these plots showed the highest linearity (R(2)=0.9833), but a close relationship was also observed with zero-order kinetics (R(2)=0.9088) and the drug release mechanism was found to be of anomalous or non-Fickian type. Further, in vitro drug release was assessed by antimicrobial assay and it revealed that drug release through 24h periods was above the MIC. In vivo investigation in rabbits showed ER pharmacokinetic profile of cefpodoxime from the matrix tablets. A good correlation of drug absorption in vivo and drug release in vitro (R(2)=0.9785) was observed. These results suggested that the investigated CFP matrix tablets have a potential for extended-release dosage forms. PMID:27155235

  15. Evaluation of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Second-Generation Lignin Analysis

    PubMed Central

    Richel, Aurore; Vanderghem, Caroline; Simon, Mathilde; Wathelet, Bernard; Paquot, Michel

    2012-01-01

    Matrix-Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) mass spectrometry is evaluated as an elucidation tool for structural features and molecular weights estimation of some extracted herbaceous lignins. Optimization of analysis conditions, using a typical organic matrix, namely α-cyano-4-hydroxycinnamic acid (CHCA), in combination with α-cyclodextrin, allows efficient ionization of poorly soluble lignin materials and suppression of matrix-related ions background. Analysis of low-mass fragments ions (m/z 100–600) in the positive ion mode offers a “fingerprint” of starting lignins that could be a fine strategy to qualitatively identify principal inter-unit linkages between phenylpropanoid units. The molecular weights of lignins are estimated using size exclusion chromatography and compared to MALDI-TOF-MS profiles. Miscanthus (Miscanthus x giganteus) and Switchgrass (Panicum Virgatum L.) lignins, recovered after a formic acid/acetic acid/water process or aqueous ammonia soaking, are selected as benchmarks for this study. PMID:23300342

  16. Studies on binary lipid matrix based solid lipid nanoparticles of repaglinide: in vitro and in vivo evaluation.

    PubMed

    Rawat, Manoj K; Jain, Achint; Singh, Sanjay

    2011-06-01

    The purpose of present study is to examine effect of binary lipid matrix (combination of lipids) on the entrapment and storage stability of repaglinide (RG) loaded solid lipid nanoparticles (SLN). Solid lipid nanoparticles were prepared by modified solvent injection method for oral delivery to improve the bioavailability of RG, an antidiabetic drug. The stearic acid and tristearin were used to form lipid core materials, and Pluronic-F68 was used as a stabilizer. Nanoparticles were characterized by evaluating their particle size, zeta potential, entrapment efficiency, drug loading, solid-state studies (differential scanning calorimetry, X-ray diffraction), in vitro drug release, particle surface (transmission electron microscopy analysis with electron diffraction pattern), stability study in gastrointestinal fluids (GIFs) and storage stability at 30 °C/65% RH for 3 months. The characterization of SLN suggested that binary lipid matrix based nanoparticles had better drug entrapment and loading, desired release characteristics, stable in GIFs and significantly higher storage stability compared with single lipid formulations. Pharmacodynamic (blood glucose, blood cholesterol, blood triglyceride levels) and pharmacokinetic (AUC, T(max), peak plasma concentrations, K, t(1/2), mean residence time and relative bioavailabilities) studies were performed for the selected formulations. These studies indicate that the formulation based on binary lipid matrix significantly improves the oral bioavailability of RG. PMID:21491449

  17. Evaluation of bone matrix gelatin/fibrin glue and chitosan/gelatin composite scaffolds for cartilage tissue engineering.

    PubMed

    Wang, Z H; Zhang, J; Zhang, Q; Gao, Y; Yan, J; Zhao, X Y; Yang, Y Y; Kong, D M; Zhao, J; Shi, Y X; Li, X L

    2016-01-01

    This study was designed to evaluate bone matrix gelatin (BMG)/fibrin glue and chitosan/gelatin composite scaffolds for cartilage tissue engineering. Chondrocytes were isolated from costal cartilage of Sprague-Dawley rats and seeded on BMG/fibrin glue or chitosan/gelatin composite scaffolds. After different in vitro culture durations, the scaffolds were subjected to hematoxylin and eosin, Masson's trichrome, and toluidine blue staining, anti-collagen II and anti-aggrecan immunohistochemistry, and scanning electronic microscopy (SEM) analysis. After 2 weeks of culture, chondrocytes were distributed evenly on the surfaces of both scaffolds. Cell numbers and the presence of extracellular matrix components were markedly increased after 8 weeks of culture, and to a greater extent on the chitosan/gelatin scaffold. The BMG/fibrin glue scaffold showed signs of degradation after 8 weeks. Immunofluorescence analysis confirmed higher levels of collagen II and aggrecan using the chitosan/gelatin scaffold. SEM revealed that the majority of cells on the surface of the BMG/fibrin glue scaffold demonstrated a round morphology, while those in the chitosan/gelatin group had a spindle-like shape, with pseudopodia. Chitosan/gelatin scaffolds appear to be superior to BMG/ fibrin glue constructs in supporting chondrocyte attachment, proliferation, and biosynthesis of cartilaginous matrix components. PMID:27525846

  18. Boundary conditions associated with the Painlevé III' and V evaluations of some random matrix averages

    NASA Astrophysics Data System (ADS)

    Forrester, P. J.; Witte, N. S.

    2006-07-01

    In a previous work a random matrix average for the Laguerre unitary ensemble, generalizing the generating function for the probability that an interval (0, s) at the hard edge contains k eigenvalues, was evaluated in terms of a Painlevé V transcendent in σ-form. However, the boundary conditions for the corresponding differential equation were not specified for the full parameter space. Here this task is accomplished in general, and the obtained functional form is compared against the most general small s behaviour of the Painlevé V equation in σ-form known from the work of Jimbo. An analogous study is carried out for the hard edge scaling limit of the random matrix average, which we have previously evaluated in terms of a Painlevé III' transcendent in σ-form. An application of the latter result is given to the rapid evaluation of a Hankel determinant appearing in a recent work of Conrey, Rubinstein and Snaith relating to the derivative of the Riemann zeta function.

  19. R-Matrix Evaluation of Cl Neutron Cross Sections up to 1.2 MeV

    SciTech Connect

    Sayer, R.O.

    2003-03-27

    We have performed an evaluation of {sup 35}Cl, {sup 37}Cl, and {sup nat}Cl neutron cross sections in the resolved resonance region with the multilevel Reich-Moore R-matrix formalism. Resonance analyses were carried out with the computer code SAMMY, which utilizes Bayes' method, a generalized least squares technique. A recent modification of SAMMY enabled us to calculate charged particle penetrabilities for the proton exit channel. Our resonance parameter representation describes the data much better than does ENDF/B-VI, and it should lead to improved criticality safety calculations for systems where Cl is present.

  20. Histopathological evaluation of the effects of variable extraoral dry times and enamel matrix proteins (enamel matrix derivatives) application on replanted dogs' teeth.

    PubMed

    Barbizam, Joao V B; Massarwa, Rasha; da Silva, Lea Assed Bezerra; da Silva, Raquel Assed Bezerra; Nelson-Filho, Paulo; Consolaro, Alberto; Cohenca, Nestor

    2015-02-01

    The extra-alveolar dry period and storage medium in which the tooth was kept prior to replantation remain the critical factors affecting the survival and regeneration of the damaged periodontium. When the replantation is delayed, replacement root resorption is the most common complication following replantation of an avulsed tooth. The aim of this histological study was to evaluate the periodontal healing of replanted dogs' teeth after 20 min (short) and 60 min (long) extraoral dry time with and without the application of enamel matrix proteins. Eighty mature premolar roots (40 teeth) maxillary and mandibular premolars were extracted, the root canals were accessed, instrumented, and filled using a lateral condensation technique, and the access cavity was restored with amalgam. Each root was randomly assigned to one of experimental groups: Groups I and II: Roots were replanted after an extraoral dry time of 20 min. In group II, Emdogain(®) (Biora, Malmo, Sweden) was applied directly to the external root surface with complete coverage. Groups III and IV: Roots were replanted after an extraoral dry time of 60 min. In group IV, Emdogain(®) was applied to the whole external root surface before replantation. Roots that replanted within a total extraoral dry time of 10 min were used as negative controls, while those replanted after 90 min of extraoral dry time were assigned as positive controls. After 4 months, the dogs were euthanized, and the maxillary and mandibular processes were processed for histology and microscopically evaluated. Statistical analysis showed no significant differences (P = 0.1075) among the experimental groups. The results of this study show that 20 min of extraoral dry time is as detrimental to the PDL cells as 60 or 90 min of extraoral dry time, with avulsed dogs' teeth, even when replanted with an inductive material such as EMD. This study provides strong evidence in relation to the threshold of the extraoral dry time of avulsed teeth

  1. Evaluation of bioprosthetic heart valve failure using a matrix-fibril shear stress transfer approach.

    PubMed

    Anssari-Benam, Afshin; Barber, Asa H; Bucchi, Andrea

    2016-02-01

    A matrix-fibril shear stress transfer approach is devised and developed in this paper to analyse the primary biomechanical factors which initiate the structural degeneration of the bioprosthetic heart valves (BHVs). Using this approach, the critical length of the collagen fibrils l c and the interface shear acting on the fibrils in both BHV and natural aortic valve (AV) tissues under physiological loading conditions are calculated and presented. It is shown that the required critical fibril length to provide effective reinforcement to the natural AV and the BHV tissue is l c  = 25.36 µm and l c  = 66.81 µm, respectively. Furthermore, the magnitude of the required shear force acting on fibril interface to break a cross-linked fibril in the BHV tissue is shown to be 38 µN, while the required interfacial force to break the bonds between the fibril and the surrounding extracellular matrix is 31 µN. Direct correlations are underpinned between these values and the ultimate failure strength and the failure mode of the BHV tissue compared with the natural AV, and are verified against the existing experimental data. The analyses presented in this paper explain the role of fibril interface shear and critical length in regulating the biomechanics of the structural failure of the BHVs, for the first time. This insight facilitates further understanding into the underlying causes of the structural degeneration of the BHVs in vivo. PMID:26715134

  2. Evaluation of sodium alginate as drug release modifier in matrix tablets.

    PubMed

    Liew, Celine Valeria; Chan, Lai Wah; Ching, Ai Ling; Heng, Paul Wan Sia

    2006-02-17

    Alginates are useful natural polymers suitable for use in the design of pharmaceutical dosage forms. However, the effects of particle size, viscosity and chemical composition of alginates on drug release from alginate matrix tablets are not clearly understood. Hence, 17 grades of sodium alginate with different particle size distributions, viscosities and chemical compositions were used to prepare matrix tablets at various concentrations to screen the factors influencing drug release from such matrices. Particle size was found to have an influence on drug release from these matrices. Sodium alginate was subsequently classified into several size fractions and also cryogenically milled to produce smaller particle size samples. Cryogenic milling could be successfully applied to pulverize coarse alginate particles without changing the quality through degradation or segregation. This study showed the significance of each alginate property in modulating drug release: particle size is important in initial alginic acid gel barrier formation as it affected the extent of burst release; higher alginate viscosity slowed down drug release rate in the buffer phase but enhanced release rate in the acid phase; high M-alginate might be more advantageous than high-G-alginate in sustaining drug release; and, the effect of increasing alginate concentration was greater with larger alginate particles. This can serve as a framework for formulators working with alginates. Furthermore, the results showed that sodium alginate matrices can sustain drug release for at least 8 h, even for a highly water-soluble drug in the presence of a water-soluble excipient. PMID:16364576

  3. Evaluating cell matrix mechanics using an integrated nonlinear optical tweezer-confocal imaging system

    NASA Astrophysics Data System (ADS)

    Peng, Berney; Alonzo, Carlo A. C.; Xia, Lawrence; Speroni, Lucia; Georgakoudi, Irene; Soto, Ana M.; Sonnenschein, Carlos; Cronin-Golomb, Mark

    2013-09-01

    Biomechanics plays a central role in breast epithelial morphogenesis. In this study we have used 3D cultures in which normal breast epithelial cells are able to organize into rounded acini and tubular ducts, the main structures found in the breast tissue. We have identified fiber organization as a main determinant of ductal organization. While bulk rheological properties of the matrix seem to play a negligible role in determining the proportion of acini versus ducts, local changes may be pivotal in shape determination. As such, the ability to make microscale rheology measurements coupled with simultaneous optical imaging in 3D cultures can be critical to assess the biomechanical factors underlying epithelial morphogenesis. This paper describes the inclusion of optical tweezers based microrheology in a microscope that had been designed for nonlinear optical imaging of collagen networks in ECM. We propose two microrheology methods and show preliminary results using a gelatin hydrogel and collagen/Matrigel 3D cultures containing mammary gland epithelial cells.

  4. Evaluation of anisotropic chitosan hydrogels using analytical Mueller matrix method and scanned laser pico-projector.

    PubMed

    Huang, Chih-Ling; Chuang, Chin-Ho; Lo, Yu-Lung

    2013-07-25

    Chitosan has excellent biodegradable, biocompatible and bio-absorbable properties and has been found increasing use in the biomedical field in recent decades. The linear birefringence (LB), linear diattenuation (LD), circular birefringence (CB), circular diattenuation (CD), and depolarization properties of chitosan hydrogel films crosslinked in citrate acid buffer solution (CBS) are extracted using an analytical Mueller matrix method. It is shown that the optical phase retardance property of the hydrogel films provides a reliable indication of both the chitosan concentration of the film and the pH value of the CBS crosslinking environment. In addition, chitosan hydrogel suspension with low-concentration crosslinked in CBS environments with various pH values are studied by the speckle contrast of the projected images obtained when illuminating the suspension with a scanned laser pico-projector (SLPP). It is found that for the samples crosslinked in an acidic environment, the speckle contrast decreases with an increasing pH value. By contrast, for the samples crosslinked in an alkaline CBS environment, the speckle contrast increases as the pH value increases. It is concluded that both the phase retardance and the speckle contrast enable the pH value of the CBS crosslinking solution to be reliably determined. However, of the two methods, the SLPP method yields improved measurement sensitivity. Overall, the results presented in this study show that the analytical Mueller matrix method and SLPP method provide an effective means of characterizing the optical properties, concentration and crosslinking environment of chitosan hydrogel films and suspensions. PMID:23768591

  5. Design and in vitro evaluation of novel sustained- release matrix tablets for lornoxicam based on the combination of hydrophilic matrix formers and basic pH-modifiers.

    PubMed

    Hamza, Yassin El-Said; Aburahma, Mona Hassan

    2010-01-01

    The short half-life of lornoxicam, a potent non-steroidal anti-inflammatory drug, makes the development of sustained-release (SR) forms extremely advantageous. However, due to its weak acidic nature, its release from SR delivery systems is limited to the lower gastrointestinal tract which consequently leads to a delayed onset of its analgesic action. Accordingly, the aim of this study was to develop lornoxicam SR matrix tablets that provide complete drug release that starts in the stomach to rapidly alleviate the painful symptoms and continues in the intestine to maintain protracted analgesic effect as well as meets the reported SR specifications. The proposed strategy was based on preparing directly compressed hydroxypropylmethylcellulose matrix tablets to sustain lornoxicam release. Basic pH-modifiers, either sodium bicarbonate or magnesium oxide, were incorporated into these matrix tablets to create basic micro-environmental pH inside the tablets favorable to drug release in acidic conditions. All the prepared matrix tablets containing basic pH-modifiers showed acceptable physical properties before and after storage. Release studies, performed in simulated gastric and intestinal fluids used in sequence to mimic the GI transit, demonstrate the possibility of sustaining lornoxicam release by combining hydrophilic matrix formers and basic pH-Modifiers to prepare tablets that meet the reported sustained-release specifications. PMID:19895367

  6. Formulation and Evaluation of Cephalexin Extended-release Matrix Tablets Using Hydroxy Propyl Methyl Cellulose as Rate-controlling Polymer

    PubMed Central

    Vijay, J; Sahadevan, JT; Prabhakaran, R; Gilhotra, R Mehra

    2012-01-01

    The present investigation reports the design and evaluation of six-hour extended release film-coated matrix tablets of cephalexin using different grades of hydrophilic polymer hydroxypropylmethylcellulose (HPMC) employing direct compression method. The preformulation studies performed included the physical compatibility studies, Differential Scanning Calorimetry analysis, drug characterization using Fourier Transform Infra Red spectroscopic analysis and particle size analysis using sieve method. The tablets were evaluated for weight variation, hardness, thickness and friability. Results of the studies indicate that the polymers used have significant release-retarding effect on the formulation. The dissolution profile comparison of the prepared batches P1 to P8 and market preparation (Sporidex AF 375) was done by using Food and Drug Administration-recommended similarity factor (f2) determination. The formulation P8 (10% HPMC K4M, 15% HPMC 15cps) with a similarity factor (f2) of 77.75 was selected as the optimized formulae for scale-up batches. The dissolution data of the best formulation P8 was fitted into zero order, first order, Higuchi and Korsemeyer-Peppas models to identify the pharmacokinetics and mechanism of drug release. The results of the accelerated stability study of best formulation P8 for three months revealed that storage conditions were not found to have made any significant changes in final formulation F3. The release of cephalexin was prolonged for 6 h by using polymer combinations of HPMC and a twice daily matrix tablet was formulated. PMID:22523453

  7. In vitro Evaluation of the Effect of Combination of Hydrophilic and Hydrophobic Polymers on Controlled Release Zidovudine Matrix Tablets.

    PubMed

    Ganesh, S; Radhakrishnan, M; Ravi, M; Prasannakumar, B; Kalyani, J

    2008-01-01

    The aim of the present study was to prepare and characterize controlled-release matrix tablets of zidovudine using hydrophilic HPMC K4 M or Carbopol 934 alone or in combination with hydrophobic ethyl cellulose. Release kinetics was evaluated by using USP XXIV dissolution apparatus No.2 (paddle) type. Scanning electron microscopy was used to visualize the effect of dissolution medium on matrix tablet surface. The in vitro results of controlled - release zidovudine tablets were compared with conventional marketed tablet Zidovir. The in vitro drug release study revealed that HPMC K4 M or Carbopol 934 preparation was able to sustain the drug release near to 6 hours. Combining HPMC K4 M or Carbopol 934 with ethyl cellulose sustained the drug release for nearly 12 h. The in vitro evaluation showed that the drug release may be by diffusion along with erosion. Results suggest that the developed controlled-release tablets of zidovudine could perform therapeutically better than marketed dosage forms, leading to improve efficacy, controlling the release and better patient compliance. PMID:20046771

  8. A Comparative Evaluation of the Wear Resistance of Various Tool Materials in Friction Stir Welding of Metal Matrix Composites

    NASA Astrophysics Data System (ADS)

    Prater, T.; Strauss, Alvin; Cook, George; Gibson, Brian; Cox, Chase

    2013-06-01

    Friction stir welding (FSW) is the preferred joining method for metal-matrix composites (MMCs). As a solid-state process, it precludes formation of the intermetallic precipitates responsible for degradation of mechanical properties in fusion welds of MMCs. The major barrier to FSW of MMCs is the rapid and severe wear of the welding pin tool, a consequence of prolonged contact between the tool and the harder reinforcements which give the material its enhanced strength. This study evaluates the effectiveness of harder tool materials to combat wear in the FSW of MMCs. The tool materials considered are O1 steel, cemented carbide (WC-Co) of the micrograin and submicrograin varieties, and WC-Co coated with diamond. The challenges which accompany the application of harder tool materials and diamond coatings in FSW are also discussed. This study represents the first use of diamond-coated tools in FSW and the first comparative evaluation of tool materials for this application.

  9. Comparative evaluation of the osteoinductivity of two formulations of human demineralized bone matrix.

    PubMed

    Takikawa, Satoshi; Bauer, Thomas W; Kambic, Helen; Togawa, Daisuke

    2003-04-01

    In the United States, demineralized bone matrix (DBM) is considered a transplantable tissue and therefore is regulated primarily by the American Association of Tissue Banks. Even though DBM is not subjected to the same regulations relative to performance claims as medical devices are, one would expect different processing methods might yield DBM preparations of different osteoinductive potential. The purpose of this study was to use an established athymic rat model to compare the osteoinductive properties of two commercially available human DBMs prepared using different methods but having essentially identical product claims. Sixteen female athymic rats were used to test equivalent volumes of two lots each of Grafton Putty (Osteotech, Inc., Eatontown, NJ), Osteofil (Regeneration Technologies, Inc., Alachua, FL), and rat DBM. At 28 days after implantation, qualitative and semiquantitative microscopy showed no significant differences in bone formation between the two lots from each source, but rat DBM produced significantly more bone than Grafton, which produced significantly more bone than Osteofil. Our results suggest that methods of graft processing may represent a greater source of variability than do differences among individual donors. Whether these differences relate to methods of demineralization, carrier, dose of DBM per volume, or to some other factor remains to be determined. PMID:12635152

  10. Biomechanical evaluation of acellular collagen matrix augmented Achilles tendon repair in sheep.

    PubMed

    Song, Lin; Olsen, Raymond E; Spalazzi, Jeffrey P; Davisson, Twana

    2010-01-01

    The rate of rerupture of repaired Achilles tendon in young and athletic populations remains high despite improvement in surgical techniques, suture design, and postsurgical management. Acellular biological matrices can be used to enhance the immediate strength of repaired tendons and to serve as scaffolds for cell in-growth and constructive tissue remodeling. A number of commercially available matrices have been used clinically, albeit with varying degrees of success and failure. The disparity is likely attributable to the different physical and biochemical properties of individual matrices. In this study, we investigated the biomechanical characteristics of 2 different acellular collagen matrices, namely TissueMend and GraftJacket, using a sheep Achilles tendon repair model. Static and cyclic creep, cyclic and linear construct stiffness, maximum load to failure, and displacement at maximum load were determined at time zero. We found that the maximum load to failure, displacement, and ultimate failure mode were similar between tendons augmented with either acellular collagen matrix; however, TissueMend augmentation yielded lower creep and smaller construct elongation than did GraftJacket. The results indicated that the strength of TissueMend-augmented tendons and GraftJacket-augmented tendons was not statistically significantly different, although tendons augmented with TissueMend displayed greater stiffness, which may be clinically advantageous in the restoration of ruptured tendons. PMID:20797586

  11. Revisiting Dialogues and Monologues

    ERIC Educational Resources Information Center

    Kvernbekk, Tone

    2012-01-01

    In educational discourse dialogue tends to be viewed as being (morally) superior to monologue. When we look at them as basic forms of communication, we find that dialogue is a two-way, one-to-one form and monologue is a one-way, one-to-many form. In this paper I revisit the alleged (moral) superiority of dialogue. First, I problematize certain…

  12. Time functions revisited

    NASA Astrophysics Data System (ADS)

    Fathi, Albert

    2015-07-01

    In this paper we revisit our joint work with Antonio Siconolfi on time functions. We will give a brief introduction to the subject. We will then show how to construct a Lipschitz time function in a simplified setting. We will end with a new result showing that the Aubry set is not an artifact of our proof of existence of time functions for stably causal manifolds.

  13. Evaluation of matrix effect in determination of some bioflavonoids in food samples by LC-MS/MS method.

    PubMed

    Ćirić, Andrija; Prosen, Helena; Jelikić-Stankov, Milena; Đurđević, Predrag

    2012-09-15

    In the present work the LC-MS/MS method with solid phase extraction for simultaneous determination of bioflavonoids rutin, quercetin, hesperidin, hesperetin and kaempferol in some food samples (red onion, orange peel and honey) was developed and the matrix effect accompanying this determination was quantified. The matrix effect evaluated using a postextraction addition method was found to be negative in the range -44 to -0.5%, indicating ionization suppression and strongly depended on bioflavonoid concentration. The observed matrix effect was explained taking into account the co-elution of phenolic acids, in terms of their acid-base and hydrophilic properties. The efficacy of extraction expressed as the absolute recoveries of flavonoids were 88-96%, indicating very good efficiency of extraction. The extracts of food samples obtained either by Soxhlet or ultrasonic extraction were analyzed for bioflavonoid content by the LC-MS/MS method in selected reaction monitoring mode using a triple quadrupole detector and standard addition method, which was found to be the most suitable calibration approach for these samples. The optimized separation was achieved on a Phenomenex Gemini C18 column with gradient elution and mobile phase composition A: 2% acetic acid in water and B: acetonitrile. R(s) values were in the range from 1.3 to 3.1, indicating good selectivity of the method. The obtained results (mg/100g fresh weight) for different bioflavonids were for rutin 0.16, for quercetin in the range 0.65-56, for hesperidin 0.016-24, for hesperetin 0.0068-36.4 and for kaempferol 0.14-1.63 and generally show good agreement with published data. Low detection limits (0.014-0.063 μg/mL) were obtained with acceptable recoveries (86-114%). Total time of analysis was less than 40 min, therefore the proposed method represents significant improvement over existing methods. PMID:22967624

  14. Evaluation of Microcracking in Two Carbon-Fiber/Epoxy-Matrix Composite Cryogenic Tanks

    NASA Technical Reports Server (NTRS)

    Hodge, A. J.

    2001-01-01

    Two graphite/epoxy cryogenic pressure vessels were evaluated for microcracking. The X-33 LH2 tank lobe skins were extensively examined for microcracks. Specimens were removed from the inner skin of the X-33 tank for tensile testing. The data obtained from these tests were used to model expected microcrack density as a function of stress. Additionally, the laminate used in the Marshall Space Flight Center (MSFC) Composite Conformal, Cryogenic, Common Bulkhead, Aerogel-Insulated Tank (CBAT) was evaluated. Testing was performed in an attempt to predict potential microcracking during testing of the CBAT.

  15. R-Matrix Evaluation of 16O Neutron Cross Sections up to 6.3 MeV

    SciTech Connect

    Sayer, R.O.

    2000-08-21

    In this paper we describe an evaluation of {sup 16}O neutron cross sections in the resolved resonance region with the multilevel Reich-Moore R-matrix formalism. Resonance analyses were performed with the computer code SAMMY [LA98] which utilizes Bayes method, a generalized least squares technique. Over the years the nuclear community has developed a collection of evaluated nuclear data for applications in thermal, fast reactor, and fusion systems. However, typical neutron spectra in criticality safety applications are different from the spectra relevant to thermal, fast reactor, and fusion systems. In fact, the neutron spectra important for these non-reactor systems appear to peak in the epithermal energy range. Nuclear data play a major role in the calculation of the criticality safety margins for these systems. A thorough examination of how the present collection of nuclear data evaluations behaves in criticality safety calculations is needed. Many older evaluations will probably need to be revised, and new evaluations will be needed. Oxygen is an important element in criticality safety applications where oxides are present in significant abundance. The existing ENDF/B-VI.5 evaluation is expressed in terms of point-wise cross sections derived from the analysis of G. Hale [HA91]. Unfortunately such an evaluation is not directly useful for resonance analysis of data from samples in which oxygen is combined with other elements; for that purpose, Reich-Moore resonance parameters are needed. This paper addresses the task of providing those parameters. In the following sections we discuss the data, resonance analysis procedure, and results.

  16. Specific surface area determinations on intact drillcores and evaluation of extrapolation methods for rock matrix surfaces.

    PubMed

    André, M; Malmström, M E; Neretnieks, I

    2009-11-01

    Permanent storage of spent nuclear fuel in crystalline bedrock is investigated in several countries. For this storage scenario, the host rock is the third and final barrier for radionuclide migration. Sorption reactions in the crystalline rock matrix have strong retardative effects on the transport of radionuclides. To assess the barrier properties of the host rock it is important to have sorption data representative of the undisturbed host rock conditions. Sorption data is in the majority of reported cases determined using crushed rock. Crushing has been shown to increase a rock samples sorption capacity by creating additional surfaces. There are several problems with such an extrapolation. In studies where this problem is addressed, simple models relating the specific surface area to the particle size are used to extrapolate experimental data to a value representative of the host rock conditions. In this article, we report and compare surface area data of five size fractions of crushed granite and of 100 mm long drillcores as determined by the Brunauer Emmet Teller (BET)-method using N(2)-gas. Special sample holders that could hold large specimen were developed for the BET measurements. Surface area data on rock samples as large as the drillcore has not previously been published. An analysis of this data show that the extrapolated value for intact rock obtained from measurements on crushed material was larger than the determined specific surface area of the drillcores, in some cases with more than 1000%. Our results show that the use of data from crushed material and current models to extrapolate specific surface areas for host rock conditions can lead to over estimation interpretations of sorption ability. The shortcomings of the extrapolation model are discussed and possible explanations for the deviation from experimental data are proposed. PMID:19781807

  17. Formulation and Evaluation of a Novel Matrix-Type Orally Disintegrating Ibuprofen Tablet

    PubMed Central

    Tayebi, Hoda; Mortazavi, Seyed Alireza

    2011-01-01

    Orally disintegrating tablets (ODTs) are capable of turning quickly into a liquid dosage form in contact with the saliva, thus possessing the advantages of both the solid dosage forms particularly stability and liquid dosage forms specially ease of swallowing and pre-gastric absorption of drug. The aim of this study was to prepare a novel matrix-type buccal fast disintegrating ibuprofen tablet formulation using special polymers, water soluble excipients, super-disintegrants and quickly soluble granules. For this purpose different tablet formulations of ibuprofen were prepared. The amount of ibuprofen in each formulation was 100 mg. Eight groups of formulation were prepared (A-H series), accounting for a total number of 45 formulations. Formulations prepared were examined in terms of different physicochemical tests including powder/granule flowability, appearance, thickness, uniformity of weight, hardness, friability and disintegration time. Results of formulation F22a (in series F), was found to be acceptable, making it the chosen formulation for further studies. Then, by adding various flavorants and sweeteners to this formulation, complementary series of formulations, named G and H, were prepared. Following the comparison of their taste with each other through asking 10 volunteers, the most suitable formulation regarding the taste, being formulation F22s, was chosen as the ultimate formulation. This formulation had PVP, ibuprofen and croscarmellose as the intra-granular components and xylitol and saccharin as the extra-granular ingredients. Formulation F22s was found to be acceptable in terms of physicochemical tests conducted, showing quick disintegration within the buccal cavity, appropriate hardness and rather low friability. Hence formulation F22s was selected as the final formulation. PMID:24250378

  18. Teacher Education: The Application of Fisher's LSD Matrix in the Evaluation of Preservice Teachers.

    ERIC Educational Resources Information Center

    Stolworthy, Reed L.

    The degrees of variance among three groups of evaluators relative to their assessments of the teaching competencies of preservice teacher education students were studied. Subjects included groups of 23 and 32 undergraduates who were certified to teach by the teacher preparation program at Washburn University in Topeka (Kansas) in 1987 and in 1988,…

  19. Isotope Inversion Experiment evaluating the suitability of calibration in surrogate matrix for quantification via LC-MS/MS-Exemplary application for a steroid multi-method.

    PubMed

    Suhr, Anna Catharina; Vogeser, Michael; Grimm, Stefanie H

    2016-05-30

    quantifying endogenous analytes. We consider it a valuable and convenient tool to evaluate the correct quantification of authentic matrix samples based on a calibration curve in surrogate matrix. PMID:26974483

  20. Design and in vitro/in vivo evaluation of extended release matrix tablets of nateglinide

    PubMed Central

    Sharma, Pushkar R.; Lewis, Shaila A.

    2013-01-01

    Aim Nateglinide is a quick acting anti-diabetic medication whose potent activity lasts for a short duration. One of the dangerous side effects of nateglinide administration is rapid hypoglycemia, a condition that needs to be monitored carefully to prevent unnecessary fatalities. The aim of the study was to develop a longer lasting and slower releasing formulation of nateglinide that could be administered just once daily. Methods Matrix tablets of nateglinide were prepared in combination with the polymers hydroxypropylmethylcellulose (HPMC), eudragits, ethyl cellulose and polyethylene oxide and the formulated drug release patterns were evaluated using in vitro and in vivo studies. Conclusion Of the seventeen formulated matrix tablets tested, only one formulation labelled HA-2 that contained 15% HPMC K4M demonstrated release profile we had aimed for. Further, swelling studies and scanning electron microscopic analysis confirmed the drug release mechanism of HA-2. The optimized formulation HA-2 was found to be stable at accelerated storage conditions for 3 months with respect to drug content and physical appearance. Mathematical analysis of the release kinetics of HA-2 indicated a coupling of diffusion and erosion mechanisms. In-vitro release studies and pharmacokinetic in vivo studies of HA-2 in rabbits confirmed the sustained drug release profile we had aimed for. PMID:24563597

  1. Biochemical and toxicological evaluation of nano-heparins in cell functional properties, proteasome activation and expression of key matrix molecules.

    PubMed

    Piperigkou, Zoi; Karamanou, Konstantina; Afratis, Nikolaos A; Bouris, Panagiotis; Gialeli, Chrysostomi; Belmiro, Celso L R; Pavão, Mauro S G; Vynios, Dimitrios H; Tsatsakis, Aristidis M

    2016-01-01

    The glycosaminoglycan heparin and its derivatives act strongly on blood coagulation, controlling the activity of serine protease inhibitors in plasma. Nonetheless, there is accumulating evidence highlighting different anticancer activities of these molecules in numerous types of cancer. Nano-heparins may have great biological significance since they can inhibit cell proliferation and invasion as well as inhibiting proteasome activation. Moreover, they can cause alterations in the expression of major modulators of the tumor microenvironment, regulating cancer cell behavior. In the present study, we evaluated the effects of two nano-heparin formulations: one isolated from porcine intestine and the other from the sea squirt Styela plicata, on a breast cancer cell model. We determined whether these nano-heparins are able to affect cell proliferation, apoptosis and invasion, as well as proteasome activity and the expression of extracellular matrix molecules. Specifically, we observed that nano-Styela compared to nano-Mammalian analogue has higher inhibitory role on cell proliferation, invasion and proteasome activity. Moreover, nano-Styela regulates cell apoptosis, expression of inflammatory molecules, such as IL-6 and IL-8 and reduces the expression levels of extracellular matrix macromolecules, such as the proteolytic enzymes MT1-MMP, uPA and the cell surface proteoglycans syndecan-1 and -2, but not on syndecan-4. The observations reported in the present article indicate that nano-heparins and especially ascidian heparin are effective agents for heparin-induced effects in critical cancer cell functions, providing an important possibility in pharmacological targeting. PMID:26476401

  2. Histologic evaluation of a biopsy specimen obtained 3 months after rotator cuff augmentation with GraftJacket Matrix.

    PubMed

    Snyder, Stephen J; Arnoczky, Steven P; Bond, James L; Dopirak, Ryan

    2009-03-01

    Understanding the cellular response to a biologic graft used in rotator cuff applications is important because foreign-body reactions and inflammation complications have historically been seen with xenograft-derived grafts. The purpose of this study was to histologically evaluate a biopsy specimen taken from a rotator cuff of a 62-year-old man 3 months after augmentation with an acellular human dermal graft, GraftJacket Matrix-MaxForce Extreme (Wright Medical Technology, Arlington, TN). The graft material was intact and filled with numerous elastic fibers and blood vessels. Extensive host cellular infiltration was evident along the margins of the graft, whereas the more central regions were more sparsely populated. Calcification and infection were not evident. There was little to no inflammatory response. The orientation of the collagen fibers indicated early organization of new tissue. The incorporation of the GraftJacket Matrix-MaxForce Extreme evidenced by cellular infiltration, alignment of collagen fibers, and blood vessel ingrowth shows that this graft exhibits key biologic factors of the remodeling process when used as an augmentation device in rotator cuff repair. PMID:19245998

  3. Evaluating the Effectiveness of Cryopreserved Acellular Dermal Matrix in Immediate Expander-Based Breast Reconstruction: A Comparison Study

    PubMed Central

    Kim, So-Young; Lim, So Young; Mun, Goo-Hyun; Bang, Sa-Ik; Oh, Kap Sung

    2015-01-01

    Background CGCryoDerm was first introduced in 2010 and offers a different matrix preservation processes for freezing without drying preparation. From a theoretical perspective, CGCryoDerm has a more preserved dermal structure and more abundant growth factors for angiogenesis and recellularization. In the current study, the authors performed a retrospective study to evaluate freezing- and freeze-drying-processed acellular dermal matrix (ADM) to determine whether any differences were present in an early complication profile. Methods Patients who underwent ADM-assisted tissue expander placement for two stage breast reconstruction between January of 2013 and March of 2014 were retrospectively reviewed and divided into two groups based on the types of ADM-assisted expander reconstruction (CGDerm vs. CGCryoDerm). Complications were divided into four main categories and recorded as follows: seroma, hematoma, infection, and mastectomy skin flap necrosis. Results In a total of 82 consecutive patients, the CGCryoDerm group had lower rates of seroma when compared to the CGDerm group without statistical significance (3.0% vs. 10.2%, P=0.221), respectively. Other complications were similar in both groups. Reconstructions with CGCryoDerm were found to have a significantly longer period of drainage when compared to reconstructions with CGDerm (11.91 days vs. 10.41 days, P=0.043). Conclusions Preliminary findings indicate no significant differences in early complications between implant/expander-based reconstructions using CGCryoderm and those using CGDerm. PMID:26015887

  4. Nanosized Borides and Carbides for Electroplating. Metal-Matrix Coatings: Specifications, Performance Evaluation

    NASA Astrophysics Data System (ADS)

    Galevskiy, G. V.; Rudneva, V. V.; Galevskiy, S. G.; Il’yashchenko, D. P.; Kartsev, D. S.

    2016-04-01

    This paper summarizes experience of application of nano-sized carbides and borides of titanium and chromium, silicon carbide as components of electro-depositable coating compositions based on nickel, zinc, and chromium. Basic physical and mechanical properties of the coatings are determined. Technological and economic evaluation is completed; practicability of high-cost nano-diamonds substitution for nano-sized borides and carbides is justified.

  5. Nondestructive Evaluation of Advanced Fiber Reinforced Polymer Matrix Composites: A Technology Assessment

    NASA Technical Reports Server (NTRS)

    Yolken, H. Thomas; Matzkanin, George A.

    2009-01-01

    Because of their increasing utilization in structural applications, the nondestructive evaluation (NDE) of advanced fiber reinforced polymer composites continues to receive considerable research and development attention. Due to the heterogeneous nature of composites, the form of defects is often very different from a metal and fracture mechanisms are more complex. The purpose of this report is to provide an overview and technology assessment of the current state-of-the-art with respect to NDE of advanced fiber reinforced polymer composites.

  6. Some fundamental aspects of fault-tree and digraph-matrix relationships for a systems-interaction evaluation procedure

    SciTech Connect

    Alesso, H.P.

    1982-02-28

    Recent events, such as Three Mile Island-2, Brown's Ferry-3, and Crystal River-3, have demonstrated that complex accidents can occur as a result of dependent (common-cause/mode) failures. These events are now being called Systems Interactions. A procedure for the identification and evaluation of Systems Interactions is being developed by the NRC. Several national laboratories and utilities have contributed preliminary procedures. As a result, there are several important views of the Systems Interaction problem. This report reviews some fundamental mathematical background of both fault-oriented and success-oriented risk analyses in order to bring out the advantages and disadvantages of each. In addition, it outlines several fault-oriented/dependency analysis approaches and several success-oriented/digraph-matrix approaches. The objective is to obtain a broad perspective of present options for solving the Systems Interaction problem.

  7. Evaluating and quantifying the potential for CO2 leakage through the caprock during carbon sequestration using a Risk Matrix

    NASA Astrophysics Data System (ADS)

    Edlmann, K.

    2012-04-01

    Geological sequestration of CO2 in deep aquifers or depleted oil/gas reservoirs is considered a solution for reducing excess CO2 currently being emitted to the atmosphere. Low permeability cap rocks trap the CO2 that is then sequestered in the underlying porous reservoir or aquifer rock. The long term dependability of CO2 sequestration is directly linked to the integrity of the caprock seals effectively trapping the CO2. Evaluation and quantification of all of the possible CO2 leakage risks and their severity and probability throughout the life of the carbon sequestration timescale is essential. This study aims to identify the CO2 leakage risks, analyse them and then evaluate the impact of each risk - will it cause leakage, how will it leak and how much will it leak? The risks assessed covered all factors that may lead to CO2 leakage including those associated with matrix permeability, CO2 diffusion, aquifer flow, scCO2 flow properties, capillary transport, effective and relative permeability of the scCO2 / brine / pore system, migration through fracture and microfracture network both existing and induced, geological discontinuities and the wellbore and drilling environment. The risks were assessed by assigning a severity and probability to each identified risk. Severity was ranked from 1 to 5; where 1 was mm scale intrusion and 5 was leakage above the top caprock. Probability was also ranked from 1 to 5; where 1 was likelihood of happening after 10,000 years and 5 was likelihood of it happening during injection. A risk matrix was produced which highlights the risks that will have the most significant impact on CO2 sequestration reliability.

  8. Preclinical Evaluation of Tegaderm™ Supported Nanofibrous Wound Matrix Dressing on Porcine Wound Healing Model

    PubMed Central

    Ong, Chee Tian; Zhang, Yanzhong; Lim, Raymond; Samsonraj, Rebekah; Masilamani, Jeyakumar; Phan, Tran Hong Ha; Ramakrishna, Seeram; Lim, Ivor; Kee, Irene; Fahamy, Mohammad; Templonuevo, Vilma; Lim, Chwee Teck; Phan, Toan Thang

    2015-01-01

    Objective: Nanofibers for tissue scaffolding and wound dressings hold great potential in realizing enhanced healing of wounds in comparison with conventional counterparts. Previously, we demonstrated good fibroblast adherence and growth on a newly developed scaffold, Tegaderm™-Nanofiber (TG-NF), made from poly ɛ-caprolactone (PCL)/gelatin nanofibers electrospun onto Tegaderm (TG). The purpose of this study is to evaluate the performance and safety of TG-NF dressings in partial-thickness wound in a pig healing model. Approach: To evaluate the rate of reepithelialization, control TG, human dermal fibroblast-seeded TG-NF(+) and -unseeded TG-NF(−) were randomly dressed onto 80 partial-thickness burns created on four female and four male pigs. Wound inspections and dressings were done after burns on day 7, 14, 21, and 28. On day 28, full-thickness biopsies were taken for histopathological evaluation by Masson-Trichrome staining for collagen and hematoxylin–eosin staining for cell counting. Results: No infection and severe inflammation were recorded. Wounds treated with TG-NF(+) reepithelialized significantly faster than TG-NF(−) and control. Wound site inflammatory responses to study groups were similar as total cell counts on granulation tissues show no significant differences. Most of the wounds completely reepithelialized by day 28, except for two wounds in control and TG-NF(−). A higher collagen coverage was also recorded in the granulation tissues treated with TG-NF(+). Innovation and Conclusion: With better reepithelialization achieved by TG-NF(+) and similar rates of wound closure by TG-NF(−) and control, and the absence of elevated inflammatory responses to TG-NF constructs, TG-NF constructs are safe and demonstrated good healing potentials that are comparable to Tegaderm. PMID:25713753

  9. Quantitative polarization and flow evaluation of choroid and sclera by multifunctional Jones matrix optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Sugiyama, S.; Hong, Y.-J.; Kasaragod, D.; Makita, S.; Miura, M.; Ikuno, Y.; Yasuno, Y.

    2016-03-01

    Quantitative evaluation of optical properties of choroid and sclera are performed by multifunctional optical coherence tomography. Five normal eyes, five glaucoma eyes and one choroidal atrophy eye are examined. The refractive error was found to be correlated with choroidal birefringence, polarization uniformity, and flow in addition to scleral birefringence among normal eyes. The significant differences were observed between the normal and the glaucoma eyes, as for choroidal polarization uniformity, flow and scleral birefringence. An automatic segmentation algorithm of retinal pigment epithelium and chorioscleral interface based on multifunctional signals is also presented.

  10. Evaluation of radiotherapy and chemotherapy effects in bone matrix using X-ray microfluorescence

    NASA Astrophysics Data System (ADS)

    Andrade, C. B. V.; Salata, C.; Silva, C. M.; Ferreira-Machado, S. C.; Braz, D.; Almeida, A. P.; Nogueira, L. P.; Barroso, R. C.; deAlmeida, C. E.; Mantuano, A.; Mota, C. L.; Pickler, A.

    2014-02-01

    Premenopausal women undergoing adjuvant chemotherapy and/or radiotherapy for Breast Cancer (BC) treatment have significant bone loss. This high bone mineral density loss can lead to an increased risk of fractures. In this study, there were evaluated parameters involved in osteoporosis when rats were subjected to a chemotherapy regimen (TC) and/or irradiation (IR). Female Wistar rats were divided into 3 groups: control (G1), TC+IR (G2) and IR (G3). The animals were euthanized after 5 months at the end of treatment and their femurs were excised and dissected. Sections of 10 μm thick were used for μXRF analysis at the National Laboratory of Synchrotron Light. The uteri of these rats were collected and weighed. The obtained results showed that animals from G2 had a significant reduction (p<0.05) of uterine mass when compared to control. The qualitative analysis performed by μXRF showed that animals from G2 had iron in bone composition of the femurs. This same result was notobserved in animals from G1 and G3 groups. These results suggest that early menopause occurs and osteoporosis begins, probably because of the absence, or reduced, production of estrogen. The presence of iron in the G2 samples in indicates the process of osteoporosis, because according to literature, this ion is competitive with calcium ions.

  11. Transfer function matrix

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1987-01-01

    Given a multivariable system, it is proved that the numerator matrix N(s) of the transfer function evaluated at any system pole either has unity rank or is a null matrix. It is also shown that N(s) evaluated at any transmission zero of the system has rank deficiency. Examples are given for illustration.

  12. Reframing in dentistry: revisited.

    PubMed

    Nuvvula, Sivakumar; Kamatham, Rekalakshmi; Challa, Ramasubbareddy; Asokan, Sharath

    2013-01-01

    The successful practice of dentistry involves a good combination of technical skills and soft skills. Soft skills or communication skills are not taught extensively in dental schools and it can be challenging to learn and at times in treating dental patients. Guiding the child's behavior in the dental operatory is one of the preliminary steps to be taken by the pediatric dentist and one who can successfully modify the behavior can definitely pave the way for a life time comprehensive oral care. This article is an attempt to revisit a simple behavior guidance technique, reframing and explain the possible psychological perspectives behind it for better use in the clinical practice. PMID:24021326

  13. Bottomonium spectrum revisited

    NASA Astrophysics Data System (ADS)

    Segovia, Jorge; Ortega, Pablo G.; Entem, David R.; Fernández, Francisco

    2016-04-01

    We revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model which has been applied to a wide range of hadronic observables from the light to the heavy quark sector, and thus the model parameters are completely constrained. Beyond the spectrum, we provide a large number of electromagnetic, strong and hadronic decays in order to discuss the quark content of the bottomonium states and give more insights about a better way to determine their properties experimentally.

  14. An evaluation of coral lophelia pertusa mucus as an analytical matrix for environmental monitoring: A preliminary proteomic study.

    PubMed

    Provan, Fiona; Nilsen, Mari Mæland; Larssen, Eivind; Uleberg, Kai-Erik; Sydnes, Magne O; Lyng, Emily; Øysæd, Kjell Birger; Baussant, Thierry

    2016-01-01

    For the environmental monitoring of coral, mucus appears to be an appropriate biological matrix due to its array of functions in coral biology and the non-intrusive manner in which it can be collected. The aim of the present study was to evaluate the feasibility of using mucus of the stony coral Lophelia pertusa (L. pertusa) as an analytical matrix for discovery of biomarkers used for environmental monitoring. More specifically, to assess whether a mass-spectrometry-based proteomic approach can be applied to characterize the protein composition of coral mucus and changes related to petroleum discharges at the seafloor. Surface-enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF MS) screening analyses of orange and white L. pertusa showed that the mucosal protein composition varies significantly with color phenotype, a pattern not reported prior to this study. Hence, to reduce variability from phenotype difference, L. pertusa white individuals only were selected to characterize in more detail the basal protein composition in mucus using liquid chromatography, mass spectrometry, mass spectrometry (LC-MS/MS). In total, 297 proteins were identified in L. pertusa mucus of unexposed coral individuals. Individuals exposed to drill cuttings in the range 2 to 12 mg/L showed modifications in coral mucus protein composition compared to unexposed corals. Although the results were somewhat inconsistent between individuals and require further validation in both the lab and the field, this study demonstrated preliminary encouraging results for discovery of protein markers in coral mucus that might provide more comprehensive insight into potential consequences attributed to anthropogenic stressors and may be used in future monitoring of coral health. PMID:27484144

  15. T wave alternans evaluation using adaptive time-frequency signal analysis and non-negative matrix factorization.

    PubMed

    Ghoraani, Behnaz; Krishnan, Sridhar; Selvaraj, Raja J; Chauhan, Vijay S

    2011-07-01

    Each year 400,000 North Americans die from sudden cardiac death (SCD). Identifying those patients at risk of SCD remains a formidable challenge. T wave alternans (TWA) evaluation is emerging as an important tool to risk stratify patients with heart diseases. TWA is a heart rate dependent phenomenon that manifests on the surface electrocardiogram (ECG) as a change in the shape or amplitude of the T wave every second heart beat. The presence of large magnitude TWA often presages lethal ventricular arrhythmias. Because the TWA signal is typically in the microvolt range, accurate detection algorithms are required to control for confounding noise and changing physiological conditions (i.e. data nonstationarity). In this study, we address the limitations of two common TWA estimation methods, spectral method (SM) and modified moving average (MMA). To overcome their limitations, we propose a modified TWA quantification framework, called Adaptive SM, that uses non-linear time-frequency distribution (TFD). In order to increase the robustness of TWA detection in ambulatory ECGs, we also propose a new technique, called non-negative matrix factorization (NMF)-Adaptive SM. We present the analytical background of these methods, and evaluate their accuracy in detecting synthetic TWA signal in simulated and real-world ambulatory ECG recordings under conditions of noise and data non-stationarity. The results of the numerical simulations support the effectiveness of the proposed approaches for TWA analysis, which may ultimately improve SCD risk assessment. PMID:21333581

  16. Property Evaluation and Damage Evolution of Environmental Barrier Coatings and Environmental Barrier Coated SiC/SiC Ceramic Matrix Composite Sub-Elements

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Halbig, Michael; Jaskowiak, Martha; Hurst, Janet; Bhatt, Ram; Fox, Dennis S.

    2014-01-01

    This paper describes recent development of environmental barrier coatings on SiC/SiC ceramic matrix composites. The creep and fatigue behavior at aggressive long-term high temperature conditions have been evaluated and highlighted. Thermal conductivity and high thermal gradient cyclic durability of environmental barrier coatings have been evaluated. The damage accumulation and complex stress-strain behavior environmental barrier coatings on SiCSiC ceramic matrix composite turbine airfoil subelements during the thermal cyclic and fatigue testing of have been also reported.

  17. Design and evaluation of matrix diffusion controlled transdermal patches of verapamil hydrochloride.

    PubMed

    Kusum Devi, V; Saisivam, S; Maria, G R; Deepti, P U

    2003-05-01

    Transdermal patches of verapamil hydrochloride were prepared using four different polymers (individual and combination): Eudragit RL100 (ERL100), Eudragit RS100 (ERS100), hydroxypropyl methylcellulose 15 cps (HPMC), and ethyl cellulose (EC), of varying degrees of hydrophilicity and hydrophobicity. The effect of the polymers on the technological properties, i.e., drug release, water vapor transmission rate (WVTR), and percentage moisture loss (ML), percentage moisture absorption (MA), folding endurance, and thickness, was investigated. Different formulations were prepared in accordance with the 2(3) factorial design, with ERL100 being the parent polymer. The patch containing ERL100 alone showed maximum WVTR, % MA, and % ML, which could be attributed to its hydrophilic nature. As expected, substitution with ERS100, HPMC, and EC decreased all the above values in accordance with their decreasing degree of hydrophilicity. In vitro release studies showed zero-order release of the drug from all the patches, and the mechanism of release was diffusion mediated. Moreover, the release of the drug was sustained and it extended over a period of 24 hr in all formulations. A12 emerged as the most satisfactory formulation insofar as its technological properties were concerned. Further, release and permeation of the drug from the most satisfactory formulation (A12) was evaluated through different biological barriers (shed snake skin, rabbit skin, and rat skin) to get an idea of the drug permeation through human skin. Shed snake's skin was found to be most permeable (82.56% drug release at 24 hr) and rat skin was least permeable (52.38%). Percutaneous absorption studies were carried out in rabbits. The pharmacokinetic parameters calculated from blood levels of the drug revealed a profile typical of a sustained release formulation, with the ability to maintain adequate plasma levels for 24 hr. [AUC: 3.09 mg/mL hr, Cmax: 203.95 microg/mL, Tmax: 8 hr]. It can therefore be concluded

  18. Targeted SPECT/CT Imaging of Matrix Metalloproteinase Activity in the Evaluation of Remodeling Tissue-Engineered Vascular Grafts Implanted in a Growing Lamb Model

    PubMed Central

    Stacy, Mitchel R.; Naito, Yuji; Maxfield, Mark W.; Kurobe, Hirotsugu; Tara, Shuhei; Chan, Chung; Rocco, Kevin A.; Shinoka, Toshiharu; Sinusas, Albert J.; Breuer, Christopher K.

    2014-01-01

    Objective(s) The clinical translation of tissue-engineered vascular grafts has been demonstrated in children. The remodeling of biodegradable, cell-seeded scaffolds to functional neovessels is partially attributed to matrix metalloproteinases. Noninvasive assessment of matrix metalloproteinase activity may indicate graft remodeling and elucidate the progression of neovessel formation. Therefore, matrix metalloproteinase activity was evaluated in grafts implanted in lambs using in vivo and ex vivo hybrid imaging. Graft growth and remodeling was quantified using in vivo X-ray computed tomography angiography. Methods Cell-seeded and unseeded scaffolds were implanted in lambs (n=5) as inferior vena cava interposition grafts. At 2 and 6 months post-implantation, in vivo angiography assessed graft morphology. In vivo and ex vivo single photon emission tomography/X-ray computed tomography imaging was performed with a radiolabeled compound targeting matrix metalloproteinase activity at 6 months. Neotissue was examined at 6 months using qualitative histologic and immunohistochemical staining and quantitative biochemical analysis. Results Seeded grafts demonstrated significant luminal and longitudinal growth from 2 to 6 months. In vivo imaging revealed subjectively higher matrix metalloproteinase activity in grafts vs. native tissue. Ex vivo imaging confirmed a quantitative increase in matrix metalloproteinase activity and demonstrated higher activity in unseeded vs. seeded grafts. Glycosaminoglycan content was increased in seeded grafts vs. unseeded grafts, without significant differences in collagen content. Conclusions Matrix metalloproteinase activity remains elevated in tissue-engineered grafts 6 months post-implantation and may indicate remodeling. Optimization of in vivo imaging to noninvasively evaluate matrix metalloproteinase activity may assist in serial assessment of vascular graft remodeling. PMID:24952823

  19. Structural Anomalies Detected in Ceramic Matrix Composites Using Combined Nondestructive Evaluation and Finite Element Analysis (NDE and FEA)

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Baaklini, George Y.; Bhatt, Ramakrishna T.

    2003-01-01

    Most reverse engineering approaches involve imaging or digitizing an object and then creating a computerized reconstruction that can be integrated, in three dimensions, into a particular design environment. The rapid prototyping technique builds high-quality physical prototypes directly from computer-aided design files. This fundamental technique for interpreting and interacting with large data sets is being used here via Velocity2 (an integrated image-processing software, ref. 1) using computed tomography (CT) data to produce a prototype three-dimensional test specimen model for analyses. A study at the NASA Glenn Research Center proposes to use these capabilities to conduct a combined nondestructive evaluation (NDE) and finite element analysis (FEA) to screen pretest and posttest structural anomalies in structural components. A tensile specimen made of silicon nitrite (Si3N4) ceramic matrix composite was considered to evaluate structural durability and deformity. Ceramic matrix composites are being sought as candidate materials to replace nickel-base superalloys for turbine engine applications. They have the unique characteristics of being able to withstand higher operating temperatures and harsh combustion environments. In addition, their low densities relative to metals help reduce component mass (ref. 2). Detailed three-dimensional volume rendering of the tensile test specimen was successfully carried out with Velocity2 (ref. 1) using two-dimensional images that were generated via computed tomography. Subsequent, three-dimensional finite element analyses were performed, and the results obtained were compared with those predicted by NDE-based calculations and experimental tests. It was shown that Velocity2 software can be used to render a three-dimensional object from a series of CT scan images with a minimum level of complexity. The analytical results (ref. 3) show that the high-stress regions correlated well with the damage sites identified by the CT scans

  20. A novel gastro-floating multiparticulate system for dipyridamole (DIP) based on a porous and low-density matrix core: in vitro and in vivo evaluation.

    PubMed

    Li, Zhao; Xu, Heming; Li, Shujuan; Li, Qijun; Zhang, Wenji; Ye, Tiantian; Yang, Xinggang; Pan, Weisan

    2014-01-30

    The study was aimed to develop a novel gastro-floating multiparticulate system based on a porous and low-density matrix core with excellent floatability. The gastro-floating pellets (GFP) were composed of a porous matrix core, a drug loaded layer (DIP and HPMC), a sub-coating layer (HPMC) and a retarding layer (Eudragit(®) NE 30D). The porous matrix cores were evaluated in specific. EC was chosen as the matrix membrane for its rigidity and minimal expansion to large extent. The porous matrix core was achieved by the complete release of the bulk water soluble excipient from the EC coated beads, and mannitol was selected as the optimal water soluble excipient. SEM photomicrographs confirmed the structure of porous matrix cores. The compositions of GFP were investigated and optimized by orthogonal array design. The optimized formulation could sustain the drug release for 12h and float on the dissolution medium for at least 12h without lag time to float. The pharmacokinetic study was conducted in beagle dogs, and the relative bioavailability of the test preparation was 193.11±3.43%. In conclusion, the novel gastro-floating pellets can be developed as a promising approach for the gastro-retentive drug delivery systems. PMID:24368104

  1. Evaluation of combined matrix-assisted laser desorption/ionization time-of-flight and matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry experiments for peptide mass fingerprinting analysis.

    PubMed

    da Silva, David; Wasselin, Thierry; Carré, Vincent; Chaimbault, Patrick; Bezdetnaya, Lina; Maunit, Benoît; Muller, Jean-François

    2011-07-15

    Peptide Mass Fingerprinting (PMF) is still of significant interest in proteomics because it allows a large number of complex samples to be rapidly screened and characterized. The main part of post-translational modifications is generally preserved. In some specific cases, PMF suffers from ambiguous or unsuccessful identification. In order to improve its reliability, a combined approach using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICRMS) was evaluated. The study was carried out on bovine serum albumin (BSA) digest. The influence of several important parameters (the matrix, the sample preparation method, the amount of the analyte) on the MOWSE score and the protein sequence coverage were evaluated to allow the identification of specific effects. A careful investigation of the sequence coverage obtained by each kind of experiment ensured the detection of specific peptides for each experimental condition. Results highlighted that DHB-FTICRMS and DHB- or CHCA-TOFMS are the most suited combinations of experimental conditions to achieve PMF analysis. The association (convolution) of the data obtained by each of these techniques ensured a significant increase in the MOWSE score and the protein sequence coverage. PMID:21638364

  2. Method Developed for the High-Temperature Nondestructive Evaluation of Fiber-Reinforced Silicon Carbide Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Goldsby, Jon C.

    1998-01-01

    Ceramic matrix composites have emerged as candidate materials to allow higher operating temperatures (1000 to 1400 C) in gas turbine engines. A need, therefore, exists to develop nondestructive methods to evaluate material integrity at the material operating temperature by monitoring thermal and mechanical fatigue. These methods would also have potential as quality inspection tools. The goal of this investigation at the NASA Lewis Research Center is to survey and correlate the temperature-dependent damping and stiffness of advanced ceramic composite materials with imposed thermal and stress histories that simulate in-service turbine engine conditions. A typical sample size of 100 by 4 by 2 cubic millimeters, along with the specified stiffness and density, placed the fundamental vibration frequencies between 100 and 2000 Hz. A modified Forster apparatus seemed most applicable to simultaneously measure both damping and stiffness. Testing in vacuum reduced the effects of air on the measurements. In this method, a single composite sample is vibrated at its fundamental tone; then suddenly, the mechanical excitation is removed so that the sample's motion freely decays with time. Typical results are illlustrated in this paper.

  3. Fractal analysis and Gray level co-occurrence matrix method for evaluation of reperfusion injury in kidney medulla.

    PubMed

    Pantic, Igor; Nesic, Zorica; Paunovic Pantic, Jovana; Radojević-Škodrić, Sanja; Cetkovic, Mila; Basta Jovanovic, Gordana

    2016-05-21

    Fractal analysis and Gray level co-occurrence matrix method represent two novel mathematical algorithms commonly used in medical sciences as potential parts of computer-aided diagnostic systems. In this study, we tested the ability of these methods to discriminate the kidney medullar tissue suffering from reperfusion injury, from normal tissue. A total of 320 digital micrographs of Periodic acid-Schiff (PAS) - stained kidney medulla from 16 Wistar albino mice (20 per animal), were analyzed using National Institutes of Health ImageJ software (NIH, Bethesda, MD) and its plugins. 160 micrographs were obtained from the experimental group with induced reperfusion injury, and another 160 were obtained from the controls. For each micrograph we calculated the values of fractal dimension, lacunarity, as well as five GLCM features: angular second moment, entropy, inverse difference moment, GLCM contrast, and GLCM correlation. Discriminatory value of the parameters was tested using receiver operating characteristic (ROC) analysis, by measuring the area below ROC curve. The results indicate that certain features of GLCM algorithm have excellent discriminatory ability in evaluation of damaged kidney tissue. Fractal dimension and lacunarity as parameters of fractal analysis also had a relatively good discriminatory value in differentiation of injured from the normal tissue. Both methods have potentially promising application in future design of novel techniques applicable in cell physiology, histology and pathology. PMID:26964774

  4. Application of fractal and grey level co-occurrence matrix analysis in evaluation of brain corpus callosum and cingulum architecture.

    PubMed

    Pantic, Igor; Dacic, Sanja; Brkic, Predrag; Lavrnja, Irena; Pantic, Senka; Jovanovic, Tomislav; Pekovic, Sanja

    2014-10-01

    This aim of this study was to assess the discriminatory value of fractal and grey level co-occurrence matrix (GLCM) analysis methods in standard microscopy analysis of two histologically similar brain white mass regions that have different nerve fiber orientation. A total of 160 digital micrographs of thionine-stained rat brain white mass were acquired using a Pro-MicroScan DEM-200 instrument. Eighty micrographs from the anterior corpus callosum and eighty from the anterior cingulum areas of the brain were analyzed. The micrographs were evaluated using the National Institutes of Health ImageJ software and its plugins. For each micrograph, seven parameters were calculated: angular second moment, inverse difference moment, GLCM contrast, GLCM correlation, GLCM variance, fractal dimension, and lacunarity. Using the Receiver operating characteristic analysis, the highest discriminatory value was determined for inverse difference moment (IDM) (area under the receiver operating characteristic (ROC) curve equaled 0.925, and for the criterion IDM≤0.610 the sensitivity and specificity were 82.5 and 87.5%, respectively). Most of the other parameters also showed good sensitivity and specificity. The results indicate that GLCM and fractal analysis methods, when applied together in brain histology analysis, are highly capable of discriminating white mass structures that have different axonal orientation. PMID:24967845

  5. Formulation development and evaluation of Diltiazem HCl sustained release matrix tablets using HPMC K4M and K100M.

    PubMed

    Qazi, Faaiza; Shoaib, Muhammad Harris; Yousuf, Rabia Ismail; Qazi, Tanveer Mustafa; Mehmood, Zafar Alam; Hasan, S M Farid

    2013-07-01

    The aim of this study was to develop a sustained release hydrophilic matrix tablet of Diltiazem HCl and evaluates the effect of formulation variables (e.g. lubricant, binder, polymer content and viscosity grades of HPMC) on drug release. Twelve different formulations (F1-F12) were prepared by direct compression. The results of the physical parameters and assay were found to be within the acceptable range. Rate of drug release was found to be slow as the fraction of the polymer was increased from 20-50%. The drug release rate from tablets containing K4M was effectively controlled by increasing the talc concentration, whereas the burst effect was reduced by increasing binder content. The drug release was higher with K4M as compare to K100M. Model-dependent and independent methods were used for data analysis and the best results were observed for K4M in Higuchi (R(2)=0.9903-0.9962) and K100M in Baker and Lonsdale (R(2)=0.9779-0.9941). The release mechanism of all formulations was non-Fickian. F7 (50% K4M, 2% talc, 10% Avicel PH101) and F11 (40% K100M) were very close to targeted release profile. F12 (50% K100M) exhibited highest degree of swelling and lowest erosion. The f1 and f2 test were performed taking F11 as a reference formulation. PMID:23811439

  6. Systematic evaluation of matrix effects in hydrophilic interaction chromatography versus reversed phase liquid chromatography coupled to mass spectrometry.

    PubMed

    Periat, Aurélie; Kohler, Isabelle; Thomas, Aurélien; Nicoli, Raul; Boccard, Julien; Veuthey, Jean-Luc; Schappler, Julie; Guillarme, Davy

    2016-03-25

    Reversed phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) is the gold standard technique in bioanalysis. However, hydrophilic interaction chromatography (HILIC) could represent a viable alternative to RPLC for the analysis of polar and/or ionizable compounds, as it often provides higher MS sensitivity and alternative selectivity. Nevertheless, this technique can be also prone to matrix effects (ME). ME are one of the major issues in quantitative LC-MS bioanalysis. To ensure acceptable method performance (i.e., trueness and precision), a careful evaluation and minimization of ME is required. In the present study, the incidence of ME in HILIC-MS/MS and RPLC-MS/MS was compared for plasma and urine samples using two representative sets of 38 pharmaceutical compounds and 40 doping agents, respectively. The optimal generic chromatographic conditions in terms of selectivity with respect to interfering compounds were established in both chromatographic modes by testing three different stationary phases in each mode with different mobile phase pH. A second step involved the assessment of ME in RPLC and HILIC under the best generic conditions, using the post-extraction addition method. Biological samples were prepared using two different sample pre-treatments, i.e., a non-selective sample clean-up procedure (protein precipitation and simple dilution for plasma and urine samples, respectively) and a selective sample preparation, i.e., solid phase extraction for both matrices. The non-selective pretreatments led to significantly less ME in RPLC vs. HILIC conditions regardless of the matrix. On the contrary, HILIC appeared as a valuable alternative to RPLC for plasma and urine samples treated by a selective sample preparation. Indeed, in the case of selective sample preparation, the compounds influenced by ME were different in HILIC and RPLC, and lower and similar ME occurrence was generally observed in RPLC vs. HILIC for urine and plasma samples

  7. Satellite failures revisited

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-12-01

    In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

  8. Anonymous Signatures Revisited

    NASA Astrophysics Data System (ADS)

    Saraswat, Vishal; Yun, Aaram

    We revisit the notion of the anonymous signature, first formalized by Yang, Wong, Deng and Wang [10], and then further developed by Fischlin [4] and Zhang and Imai [11]. We present a new formalism of anonymous signature, where instead of the message, a part of the signature is withheld to maintain anonymity. We introduce the notion unpretendability to guarantee infeasibility for someone other than the correct signer to pretend authorship of the message and signature. Our definition retains applicability for all previous applications of the anonymous signature, provides stronger security, and is conceptually simpler. We give a generic construction from any ordinary signature scheme, and also show that the short signature scheme by Boneh and Boyen [2] can be naturally regarded as such a secure anonymous signature scheme according to our formalism.

  9. Revisiting Lambert's problem

    NASA Astrophysics Data System (ADS)

    Izzo, Dario

    2015-01-01

    The orbital boundary value problem, also known as Lambert problem, is revisited. Building upon Lancaster and Blanchard approach, new relations are revealed and a new variable representing all problem classes, under L-similarity, is used to express the time of flight equation. In the new variable, the time of flight curves have two oblique asymptotes and they mostly appear to be conveniently approximated by piecewise continuous lines. We use and invert such a simple approximation to provide an efficient initial guess to an Householder iterative method that is then able to converge, for the single revolution case, in only two iterations. The resulting algorithm is compared, for single and multiple revolutions, to Gooding's procedure revealing to be numerically as accurate, while having a significantly smaller computational complexity.

  10. Quantum duel revisited

    NASA Astrophysics Data System (ADS)

    Schmidt, Alexandre G. M.; Paiva, Milena M.

    2012-03-01

    We revisit the quantum two-person duel. In this problem, both Alice and Bob each possess a spin-1/2 particle which models dead and alive states for each player. We review the Abbott and Flitney result—now considering non-zero α1 and α2 in order to decide if it is better for Alice to shoot or not the second time—and we also consider a duel where players do not necessarily start alive. This simple assumption allows us to explore several interesting special cases, namely how a dead player can win the duel shooting just once, or how can Bob revive Alice after one shot, and the better strategy for Alice—being either alive or in a superposition of alive and dead states—fighting a dead opponent.

  11. Evaluation of the matrix effect of different sample matrices for 33 pharmaceuticals by post-column infusion.

    PubMed

    Rossmann, Julia; Gurke, Robert; Renner, Lars David; Oertel, Reinhard; Kirch, Wilhelm

    2015-09-01

    Matrix effects that occur during quantitative measurement by liquid chromatography mass spectrometry specifically when using electrospray ionization are a widely recognized phenomenon. Sample matrix compounds affect the ionization process of the target analytes, lead to a low signal response, and flawed analytical results. How these matrix compounds directly influence the ionization process has not yet been completely understood. In the present study, we determined the matrix effect for 33 pharmaceutical substances in sample extracts of urine, plasma and wastewater. Most of the investigated substances were subject to a signal suppression effect. Only for a small subset of the compounds we detected a signal enhancement effect. We investigated the matrix effect profiles in detail to disentangle the influence of different matrices and to correlate the impact of specific components and groups of the analyzed extract in suppressing or enhancing effects in the profile. Most signal suppression effects were detected in the first half of the chromatographic run-time for the matrix extracts of urine and wastewater. The observed effects are caused by high mass flow of salts and other diverse matrix components that were contained in high concentrations in those biological matrices. We also found signal suppression in the matrix effect profile of plasma samples over a wide time range during the chromatographic separation that were associated with a high content of triglycerides of diverse carbohydrate chain lengths. Here, we provide a broader picture of how 33 substances were influenced during analysis. Our results imply that a high number of the investigated substances had comparable effects of matrix compounds, despite differences in their chemical structure. PMID:26210586

  12. Evaluation of efficacy of enamel matrix derivative in the treatment of intrabony defects: a 24-month multicenter study.

    PubMed

    Francetti, Luca; Trombelli, Leonardo; Lombardo, Giorgio; Guida, Luigi; Cafiero, Carlo; Roccuzzo, Mario; Carusi, Giorgio; Del Fabbro, Massimo

    2005-10-01

    The aim of this prospective multicenter controlled clinical study was to evaluate the efficacy of Emdogain (Biora), an enamel matrix derivative (EMD), when combined with surgical treatment of periodontal angular defects, as compared to surgery alone, for up to 24 months of follow-up. The study was performed at six Italian universities and 11 private practices. Patients with one-, two-, or three-wall angular defects were enrolled if intrabony defect depth (IBD) was 4 mm or more and probing pocket depth (PPD) was at least 6 mm. They were randomly allocated to either test or control groups. The test group was treated by the simplified papilla preservation (SPP) flap plus Emdogain after root conditioning with ethylenediaminetetraacetic acid. The control group was treated by SPP alone. Plaque Index, Gingival Index, PPD, and periodontal attachment level (PAL) at surgical sites were assessed at the presurgical examination (baseline). IBD was measured intraoperatively after debridement. IBD was also evaluated with a computer-aided technique, from periapical radiographs. Plaque Index, Gingival Index, PPD, PAL, and IBD were assessed at 12 and 24 months postsurgery. Data were further divided in two subgroups according to baseline IBD (6 mm or less and more than 6 mm). The differences between each follow-up and baseline, and between groups at each follow-up, for the above parameters were evaluated by standard statistical methods. One hundred fifty-three patients were recruited, accounting for 195 intrabony defects: 83 patients (108 defects) and 70 patients (87 defects) were allocated to the test and control groups, respectively. All parameters were improved at both 12 and 24 months, compared to baseline in both groups. In the test group, IBD, PPD, and PAL at 12 months were significantly better than these parameters in the control group. The test subgroup with IBD of more than 6 mm at baseline displayed a better outcome when compared to the 6 mm or less IBD subgroup. No

  13. Addressable test matrix for measuring analog transfer characteristics of test elements used for integrated process control and device evaluation

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor)

    1988-01-01

    A set of addressable test structures, each of which uses addressing schemes to access individual elements of the structure in a matrix, is used to test the quality of a wafer before integrated circuits produced thereon are diced, packaged and subjected to final testing. The electrical characteristic of each element is checked and compared to the electrical characteristic of all other like elements in the matrix. The effectiveness of the addressable test matrix is in readily analyzing the electrical characteristics of the test elements and in providing diagnostic information.

  14. Evaluation of the matrix effect of thermophilic anaerobic digestion on inactivation of infectious laryngotracheitis virus using real-time PCR and viral cell culture.

    PubMed

    Gao, Tiejun; Bowlby, Evelyn; Tong, Yupin; Wu, John T Y; Wong, Lester; Tower, Robert J; Pang, Xiaoli; Li, Xiaomei

    2012-04-01

    The matrix effect of the thermophilic anaerobic digestion (TAD) process on inactivation of infectious laryngotracheitis virus (ILTV) was evaluated. Viral cell culture and real-time PCR were used for assessing removal of the viral infectivity and degradation of viral DNA, respectively. Results showed that the TAD-derived matrix alone can inactivate the virus and destroy the nucleic acid helix core of ILTV in a time-and- dose-dependent manner. No cytopathogenic effect (CPE) was observed in the cells exposed to ILTV pre-treated with TAD matrix for 1.5h in experiment 1 and for 16h in experiment 2. There was a significant statistical difference between TAD matrix treated and non-treated cultures (p<0.001, Chi-test). Amplifiable ILT viral DNA was reduced 2.27 log by 1.5h-treatment and was not present by 16h-treatment with TAD matrix, indicating complete viral DNA fragmentation. The TAD process is an environmentally friendly way for disposing of poultry biowaste and carcasses. PMID:22349192

  15. Evaluation of the impacts of formulation variables and excipients on the drug release dynamics of a polyamide 6,10-based monolithic matrix using mathematical tools.

    PubMed

    Adeleke, Oluwatoyin A; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; Tomar, Lomas K; Tyagi, Charu; Pillay, Viness

    2013-12-01

    Drug release from hydrophilic matrices is regulated mainly by polymeric erosion, disentanglement, dissolution, swelling front movement, drug dissolution and diffusion through the polymeric matrix. These processes depend upon the interaction between the dissolution media, polymeric matrix and drug molecules, which can be significantly influenced by formulation variables and excipients. This study utilized mathematical parameters to evaluate the impacts of selected formulation variables and various excipients on the release performance of hydrophilic polyamide 6,10 (PA 6,10) monolithic matrix. Amitriptyline HCl and theophylline were employed as the high and low solubility model drugs, respectively. The incorporation of different excipient concentrations and changes in formulation components influenced the drug release dynamics as evidenced by computed mathematical quantities (t x%, MDT x%, f 1, f 2, k 1, k 2, and К F). The effects of excipients on drug release from the PA 6,10 monolithic matrix was further elucidated using static lattice atomistic simulations wherein the component energy refinements corroborates the in vitro and in silico experimental data. Consequently, the feasibility of modulating release kinetics of drug molecules from the novel PA 6,10 monolithic matrix was well suggested. PMID:23990121

  16. Evaluation of Silk Biomaterials in Combination with Extracellular Matrix Coatings for Bladder Tissue Engineering with Primary and Pluripotent Cells

    PubMed Central

    Franck, Debra; Gil, Eun Seok; Adam, Rosalyn M.; Kaplan, David L.; Chung, Yeun Goo; Estrada, Carlos R.; Mauney, Joshua R.

    2013-01-01

    Silk-based biomaterials in combination with extracellular matrix (ECM) coatings were assessed as templates for cell-seeded bladder tissue engineering approaches. Two structurally diverse groups of silk scaffolds were produced by a gel spinning process and consisted of either smooth, compact multi-laminates (Group 1) or rough, porous lamellar-like sheets (Group 2). Scaffolds alone or coated with collagen types I or IV or fibronectin were assessed independently for their ability to support attachment, proliferation, and differentiation of primary cell lines including human bladder smooth muscle cells (SMC) and urothelial cells as well as pluripotent cell populations, such as murine embryonic stem cells (ESC) and induced pluripotent stem (iPS) cells. AlamarBlue evaluations revealed that fibronectin-coated Group 2 scaffolds promoted the highest degree of primary SMC and urothelial cell attachment in comparison to uncoated Group 2 controls and all Group 1 scaffold variants. Real time RT-PCR and immunohistochemical (IHC) analyses demonstrated that both fibronectin-coated silk groups were permissive for SMC contractile differentiation as determined by significant upregulation of α-actin and SM22α mRNA and protein expression levels following TGFβ1 stimulation. Prominent expression of epithelial differentiation markers, cytokeratins, was observed in urothelial cells cultured on both control and fibronectin-coated groups following IHC analysis. Evaluation of silk matrices for ESC and iPS cell attachment by alamarBlue showed that fibronectin-coated Group 2 scaffolds promoted the highest levels in comparison to all other scaffold formulations. In addition, real time RT-PCR and IHC analyses showed that fibronectin-coated Group 2 scaffolds facilitated ESC and iPS cell differentiation toward both urothelial and smooth muscle lineages in response to all trans retinoic acid as assessed by induction of uroplakin and contractile gene and protein expression. These results

  17. Synthesis of silica coated zinc oxide–poly(ethylene-co-acrylic acid) matrix and its UV shielding evaluation

    SciTech Connect

    Ramasamy, Mohankandhasamy; Kim, Yu Jun; Gao, Haiyan; Yi, Dong Kee; An, Jeong Ho

    2014-03-01

    Graphical abstract: - Highlights: • Well layer thickness controlled silica shell was made on ZnO nanoparticles. • PEAA, an interfacial agent is used to make nanocomposite–polymer matrix by twin-screw extruder. • Si-ZnO/PEAA matrix is highly stable and UV protective as compared to ZnO/PEAA matrix. • Nanoparticle embedded polymer matrix is suggested to make UV shielding fabrics with Nylon4. - Abstract: Silica coated zinc oxide nanoparticles (Si-ZnO NPs) (7 nm thick) were synthesized successfully and melt blended with poly(ethylene-co-acrylic acid) (PEAA resin) to improving ultraviolet (UV) shielding of zinc oxide nanoparticles (ZnO NPs). The photostability of both the ZnO NPs and Si-ZnO NPs were analyzed by the difference in photoluminescence (PL) and by methylene blue (MB) degradation. Photo-degradation studies confirmed that Si-ZnO NPs are highly photostable compared to ZnO NPs. The melt blended matrices were characterized by field emission scanning electron microscopy interfaced with energy dispersive X-ray spectroscopy (FE-SEM-EDX). The UV shielding property was analyzed from the transmittance spectra of UV–visible (UV–vis) spectroscopy. The results confirmed fine dispersion of thick Si-ZnO NPs in the entire resin matrix. Moreover, the Si-ZnO/PEAA showed about 97% UV shielding properties than the ZnO/PEAA.

  18. Evaluation of dermal extracellular matrix and epidermal-dermal junction modifications using matrix-assisted laser desorption/ionization mass spectrometric imaging, in vivo reflectance confocal microscopy, echography, and histology: effect of age and peptide applications.

    PubMed

    Mondon, Philippe; Hillion, Mélanie; Peschard, Olivier; Andre, Nada; Marchand, Thibault; Doridot, Emmanuel; Feuilloley, Marc Gj; Pionneau, Cédric; Chardonnet, Solenne

    2015-06-01

    This study was conducted to establish a new methodology for evaluating elements of dermal extracellular matrix (ECM), of epidermal-dermal junction (EDJ), and effects of molecules which can modulate their synthesis. This methodology is based on matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI). In vivo reflectance confocal microscopy (in vivo RCM) and echography were also used. Using immunohistochemistry methods on explants, age-related modification data were obtained for selected dermal ECM and EDJ proteins (collagen I, collagen IV, collagen VII, collagen XVII, nidogen I, decorin/decorunt) and used as reference for MALDI-MSI studies. A methodology was developed with MALDI-MSI to map epidermis and dermis proteins. Then MALDI-MSI was used to study age modifications. In vivo RCM and high-frequency ultrasounds were used to evaluate ECM and EDJ undulation modifications caused by aging. Anti-aging molecule evaluations were performed with a blend of palmitoyl oligopeptide and palmitoyl tetrapeptide-7. Immunohistochemistry studies demonstrated that the selected proteins were found to be less abundant in aged group explants vs. young group except for decorin. MALDI-MSI studies correlated the results obtained for decorin. In vivo RCM measurements indicated a decrease of EDJ undulation depth with age and ECM modifications in the upper part of dermis. Echography demonstrated that the peptide blend reduced subepidermal low-echogenic band thickness and improved its density. In vivo RCM studies indicated that the peptides improved the ECM structure vs. placebo. This preliminary MALDI-MSI study raised some technical difficulties that were overcome. Further studies will be conducted to identify more proteins and to demonstrate the interest of this method for cosmetic evaluations. PMID:25817264

  19. Application of matrix singular value properties for evaluating gain and phase margins of multiloop systems. [stability margins for wing flutter suppression and drone lateral attitude control

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, V.; Newsom, J. R.

    1982-01-01

    A stability margin evaluation method in terms of simultaneous gain and phase changes in all loops of a multiloop system is presented. A universal gain-phase margin evaluation diagram is constructed by generalizing an existing method using matrix singular value properties. Using this diagram and computing the minimum singular value of the system return difference matrix over the operating frequency range, regions of guaranteed stability margins can be obtained. Singular values are computed for a wing flutter suppression and a drone lateral attitude control problem. The numerical results indicate that this method predicts quite conservative stability margins. In the second example if the eigenvalue magnitude is used instead of the singular value, as a measure of nearness to singularity, more realistic stability margins are obtained. However, this relaxed measure generally cannot guarantee global stability.

  20. Evaluating our understanding of the biological carbon pump using the transport matrix method and global nutrient distributions.

    NASA Astrophysics Data System (ADS)

    Bernardello, Raffaele; Martin, Adrian; Khatiwala, Samar; Kriest, Iris; Henson, Stephanie; Dunne, John; Totterdell, Ian; Allen, Icarus; Yool, Andrew

    2015-04-01

    Global net primary production by marine phytoplankton plays a key role in the Earth system, fuelling the marine ecosystem and supporting resources such as fisheries. A fraction of the resulting organic material sinks out of the euphotic zone as 'export production', sequestering large amounts of carbon at depth, away from the atmosphere. Model studies have demonstrated that atmospheric pCO2 concentrations can be very sensitive to small changes in the depth at which this organic material is remineralised into CO2 and nutrients. The accuracy of parameterisations for remineralisation has often been assessed by direct comparison of simulated and sparse observed fluxes of sinking material. The consequences of remineralisation, i.e. the global distribution of inorganic nutrients, provide a much stronger test of our knowledge concerning the impact of remineralisation on ocean nutrient cycles because they are much more densely sampled. In this study, we investigate how alternative paradigms for the Biological Carbon Pump (BCP) have distinctive signatures in the consequent global distribution of nutrients. We compare several combinations of parameterisations for export production and remineralisation within two different representations of ocean circulation using the Transport Matrix Method (Khatiwala, 2007). Export production is represented using an NPZD-DOP model (Kriest et al., 2010) and three remote sensing-derived estimates while remineralisation is represented by either constant or spatially variable values of the Martin's curve exponent (Martin et al., 1987). In order to evaluate the ability of each export-remineralisation combination to correctly represent the BCP, we introduce a set of diagnostics to allow the intercomparison between in-situ data and simulations. These diagnostics are based on both nutrient fields and water masses and are designed to minimize the influence of biases originating from the representation of ocean circulation on the model

  1. Evaluation of matrix-assisted laser desorption ionization-time-of-flight mass spectrometry for species identification of nonfermenting Gram-negative bacilli.

    PubMed

    Almuzara, Marisa; Barberis, Claudia; Traglia, Germán; Famiglietti, Angela; Ramirez, Maria Soledad; Vay, Carlos

    2015-05-01

    Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) to identify 396 Nonfermenting Gram-Negative Bacilli clinical isolates was evaluated in comparison with conventional phenotypic tests and/or molecular methods. MALDI-TOF MS identified to species level 256 isolates and to genus or complex level 112 isolates. It identified 29 genera including uncommon species. PMID:25765149

  2. Multinomial pattern matching revisited

    NASA Astrophysics Data System (ADS)

    Horvath, Matthew S.; Rigling, Brian D.

    2015-05-01

    Multinomial pattern matching (MPM) is an automatic target recognition algorithm developed for specifically radar data at Sandia National Laboratories. The algorithm is in a family of algorithms that first quantizes pixel value into Nq bins based on pixel amplitude before training and classification. This quantization step reduces the sensitivity of algorithm performance to absolute intensity variation in the data, typical of radar data where signatures exhibit high variation for even small changes in aspect angle. Our previous work has focused on performance analysis of peaky template matching, a special case of MPM where binary quantization is used (Nq = 2). Unfortunately references on these algorithms are generally difficult to locate and here we revisit the MPM algorithm and illustrate the underlying statistical model and decision rules for two algorithm interpretations: the 1-of-K vector form and the scalar. MPM can also be used as a detector and specific attention is given to algorithm tuning where "peak pixels" are chosen based on their underlying empirical probabilities according to a reward minimization strategy aimed at reducing false alarms in the detection scenario and false positives in a classification capacity. The algorithms are demonstrated using Monte Carlo simulations on the AFRL civilian vehicle dataset for variety of choices of Nq.

  3. Lorentz violation naturalness revisited

    NASA Astrophysics Data System (ADS)

    Belenchia, Alessio; Gambassi, Andrea; Liberati, Stefano

    2016-06-01

    We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-energy percolation also in this case.

  4. Stacking Global Seismograms Revisited

    NASA Astrophysics Data System (ADS)

    Shearer, P. M.; Buehler, J. S.; Denolle, M.; Fan, W.; Ma, Z.; Mancinelli, N. J.; Matoza, R. S.; Wang, W.; Wang, Y.; Zhan, Z.

    2014-12-01

    Over 20 years ago, stacks of global seismograms produced direct images of the global seismic wavefield highlighting the visibility, frequency content, and polarity of known seismic phases, and also identified a host of new phases associated with reflections and phase conversions from upper-mantle discontinuities. Two different stacking methods proved particularly useful: (1) STA/LTA-filtered stacks that describe the local signal-to-noise characteristics of the major seismic phases. These serve to image the entire wavefield in a uniform way for educational purposes and to show which phases are observed most clearly as a guide to future research. These stacks also resolve SH versus SV timing differences consistent with radial anisotropy. (2) Reference-phase stacks that preserve the polarity, amplitude, and timing of traces with respect to a specified target phase. These show a large number of top-side and bottom-side reflections and phase conversions from the 410- and 660-km discontinuities that create weak phases with a characteristic "railroad track" appearance both preceding and following many of the main seismic phases. Reference-phase stacking can also be used to produce coherent surface-wave stacks at very long periods, which directly show the dispersive character of the surface waves. Here we revisit and update these stacks by exploiting the vastly increased data now available from the IRIS DMC to produce greatly improved wavefield images. We present several examples of the different stacking approaches and point out their various features, including promising targets for future research.

  5. CGL description revisited

    NASA Astrophysics Data System (ADS)

    Hunana, P.; Zank, G. P.; Goldstein, M. L.; Webb, G. M.; Adhikari, L.

    2016-03-01

    Solar wind observational studies have emphasized that the solar wind plasma data is bounded by the mirror and firehose instabilities, and it is often believed that these instabilities are of a purely kinetic nature. The simplest fluid model that generalizes magnetohydrodynamics with anisotropic temperatures is the Chew-Goldberger-Low model (CGL). Here we briefly revisit the CGL description and discuss its (otherwise well-documented) linear firehose and mirror instability thresholds; namely that the firehose instability threshold is identical to the one found from linear kinetic theory and that the mirror threshold contains a factor of 6 error. We consider a simple higher-order fluid model with time dependent heat flux equations and show that the mirror instability threshold is correctly reproduced. We also present fully nonlinear three-dimensional simulations of freely decaying turbulence for the Hall-CGL model with isothermal electrons. The spatial resolution of these simulations is 5123 and the formation of a spectral break in magnetic and velocity field spectra around the proton inertial length is found.

  6. Searle's"Dualism Revisited"

    SciTech Connect

    P., Henry

    2008-11-20

    A recent article in which John Searle claims to refute dualism is examined from a scientific perspective. John Searle begins his recent article 'Dualism Revisited' by stating his belief that the philosophical problem of consciousness has a scientific solution. He then claims to refute dualism. It is therefore appropriate to examine his arguments against dualism from a scientific perspective. Scientific physical theories contain two kinds of descriptions: (1) Descriptions of our empirical findings, expressed in an every-day language that allows us communicate to each other our sensory experiences pertaining to what we have done and what we have learned; and (2) Descriptions of a theoretical model, expressed in a mathematical language that allows us to communicate to each other certain ideas that exist in our mathematical imaginations, and that are believed to represent, within our streams of consciousness, certain aspects of reality that we deem to exist independently of their being perceived by any human observer. These two parts of our scientific description correspond to the two aspects of our general contemporary dualistic understanding of the total reality in which we are imbedded, namely the empirical-mental aspect and the theoretical-physical aspect. The duality question is whether this general dualistic understanding of ourselves should be regarded as false in some important philosophical or scientific sense.

  7. Revisiting caspases in sepsis

    PubMed Central

    Aziz, M; Jacob, A; Wang, P

    2014-01-01

    Sepsis is a life-threatening illness that occurs due to an abnormal host immune network which extends through the initial widespread and overwhelming inflammation, and culminates at the late stage of immunosupression. Recently, interest has been shifted toward therapies aimed at reversing the accompanying periods of immune suppression. Studies in experimental animals and critically ill patients have demonstrated that increased apoptosis of lymphoid organs and some parenchymal tissues contributes to this immune suppression, anergy and organ dysfunction. Immediate to the discoveries of the intracellular proteases, caspases for the induction of apoptosis and inflammation, and their striking roles in sepsis have been focused elaborately in a number of original and review articles. Here we revisited the different aspects of caspases in terms of apoptosis, pyroptosis, necroptosis and inflammation and focused their links in sepsis by reviewing several recent findings. In addition, we have documented striking perspectives which not only rewrite the pathophysiology, but also modernize our understanding for developing novel therapeutics against sepsis. PMID:25412304

  8. Cats protecting birds revisited.

    PubMed

    Fan, Meng; Kuang, Yang; Feng, Zhilan

    2005-09-01

    In this paper, we revisit the dynamical interaction among prey (bird), mesopredator (rat), and superpredator (cat) discussed in [Courchamp, F., Langlais, M., Sugihara, G., 1999. Cats protecting birds: modelling the mesopredator release effect. Journal of Animal Ecology 68, 282-292]. First, we develop a prey-mesopredator-superpredator (i.e., bird-rat-cat, briefly, BRC) model, where the predator's functional responses are derived based on the classical Holling's time budget arguments. Our BRC model overcomes several model construction problems in Courchamp et al. (1999), and admits richer, reasonable and realistic dynamics. We explore the possible control strategies to save or restore the bird by controlling or eliminating the rat or the cat when the bird is endangered. We establish the existence of two types of mesopredator release phenomena: severe mesopredator release, where once superpredators are suppressed, a burst of mesopredators follows which leads their shared prey to extinction; and mild mesopredator release, where the mesopredator release could assert more negative impact on the endemic prey but does not lead the endemic prey to extinction. A sharp sufficient criterion is established for the occurrence of severe mesopredator release. We also show that, in a prey-mesopredator-superpredator trophic food web, eradication of introduced superpredators such as feral domestic cats in the BRC model, is not always the best solution to protect endemic insular prey. The presence of a superpredator may have a beneficial effect in such systems. PMID:15998496

  9. 42 CFR 488.30 - Revisit user fee for revisit surveys.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 5 2012-10-01 2012-10-01 false Revisit user fee for revisit surveys. 488.30 Section 488.30 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES General Provisions § 488.30 Revisit user fee...

  10. Evaluation of the matrix exponential for use in ground-water-flow and solute-transport simulations; theoretical framework

    USGS Publications Warehouse

    Umari, A.M.; Gorelick, S.M.

    1986-01-01

    It is possible to obtain analytic solutions to the groundwater flow and solute transport equations if space variables are discretized but time is left continuous. From these solutions, hydraulic head and concentration fields for any future time can be obtained without ' marching ' through intermediate time steps. This analytical approach involves matrix exponentiation and is referred to as the Matrix Exponential Time Advancement (META) method. Two algorithms are presented for the META method, one for symmetric and the other for non-symmetric exponent matrices. A numerical accuracy indicator, referred to as the matrix condition number, was defined and used to determine the maximum number of significant figures that may be lost in the META method computations. The relative computational and storage requirements of the META method with respect to the time marching method increase with the number of nodes in the discretized problem. The potential greater accuracy of the META method and the associated greater reliability through use of the matrix condition number have to be weighed against this increased relative computational and storage requirements of this approach as the number of nodes becomes large. For a particular number of nodes, the META method may be computationally more efficient than the time-marching method, depending on the size of time steps used in the latter. A numerical example illustrates application of the META method to a sample ground-water-flow problem. (Author 's abstract)

  11. Comment on ``Valence-bond theory and the evaluation of electronic energy matrix elements between nonorthogonal Slater determinants''

    NASA Astrophysics Data System (ADS)

    Gallup, G. A.

    1986-07-01

    In a recent article [Phys. Rev. A 31, 2107 (1985)] Leasure and Balint-Kurti claim to give a more efficient algorithm than any previously available for determining matrix elements of the Hamiltonian in valence-bond calculations. Actually, an algorithm of no significant difference and the same efficiency has been available since 1972 and has been applied to valence-bond calculations.

  12. Formulation and evaluation of ileo-colonic targeted matrix-mini-tablets of Naproxen for chronotherapeutic treatment of rheumatoid arthritis.

    PubMed

    Hadi, Mohd Abdul; Raghavendra Rao, N G; Srinivasa Rao, A

    2016-01-01

    In this present research work, the aim was to develop ileo-colonic targeted matrix-mini-tablets-filled capsule system of Naproxen for chronotherapeutic treatment of Rheumatoid Arthritis. So Matrix-mini-tablets of Naproxen were prepared using microsomal enzyme dependent and pH-sensitive polymers by direct compression method which were further filled into an empty HPMC capsule. The compatibility was assessed using FT-IR and DSC studies for pure drug, polymers and their physical mixtures. The prepared batches were subjected to physicochemical studies, drug content estimation, in-vitro drug release and stability studies. When FTIR and DSC studies were performed, it was found that there was no interaction between Naproxen and polymers used. The physicochemical properties of all the prepared matrix-mini-tablets batches were found to be in limits. The drug content percentage in the optimized formulation F18 was found to be 99.24 ± 0.10%. Our optimized matrix-mini-tablets-filled-capsule formulation F18 releases Naproxen after a lag time of 2.45 ± 0.97 h and 27.30 ± 0.86%, 92.59 ± 0.47%, 99.38 ± 0.69% at the end of 5, 8, 12 h respectively. This formulation was also found to be stable as per the guidelines of International Conference on Harmonisation of Technical Requirements of Pharmaceuticals for Human Use. Thus, a novel ileo-colonic targeted delivery system of Naproxen was successfully developed by filling matrix-mini-tablets into an empty HPMC capsule shell for targeting early morning peak symptoms of rheumatoid arthritis. PMID:26903770

  13. Formulation and evaluation of ileo-colonic targeted matrix-mini-tablets of Naproxen for chronotherapeutic treatment of rheumatoid arthritis

    PubMed Central

    Hadi, Mohd Abdul; Raghavendra Rao, N.G.; Srinivasa Rao, A.

    2015-01-01

    In this present research work, the aim was to develop ileo-colonic targeted matrix-mini-tablets-filled capsule system of Naproxen for chronotherapeutic treatment of Rheumatoid Arthritis. So Matrix-mini-tablets of Naproxen were prepared using microsomal enzyme dependent and pH-sensitive polymers by direct compression method which were further filled into an empty HPMC capsule. The compatibility was assessed using FT-IR and DSC studies for pure drug, polymers and their physical mixtures. The prepared batches were subjected to physicochemical studies, drug content estimation, in-vitro drug release and stability studies. When FTIR and DSC studies were performed, it was found that there was no interaction between Naproxen and polymers used. The physicochemical properties of all the prepared matrix-mini-tablets batches were found to be in limits. The drug content percentage in the optimized formulation F18 was found to be 99.24 ± 0.10%. Our optimized matrix-mini-tablets-filled-capsule formulation F18 releases Naproxen after a lag time of 2.45 ± 0.97 h and 27.30 ± 0.86%, 92.59 ± 0.47%, 99.38 ± 0.69% at the end of 5, 8, 12 h respectively. This formulation was also found to be stable as per the guidelines of International Conference on Harmonisation of Technical Requirements of Pharmaceuticals for Human Use. Thus, a novel ileo-colonic targeted delivery system of Naproxen was successfully developed by filling matrix-mini-tablets into an empty HPMC capsule shell for targeting early morning peak symptoms of rheumatoid arthritis. PMID:26903770

  14. Erratum: Interstellar Abundance Standards Revisited

    NASA Astrophysics Data System (ADS)

    Sofia, U. J.; Meyer, D. M.

    2001-09-01

    In the Letter ``Interstellar Abundance Standards Revisited'' by U. J. Sofia and D. M. Meyer (ApJ, 554, L221 [2001]), Table 2 and its footnotes contain several typographical errors. The corrected table is shown below. We note that the solar reference standard now implies a positive abundance of nitrogen in halo dust.

  15. Cultural Warping of Childbirth, Revisited

    PubMed Central

    Budin, Wendy C.

    2007-01-01

    In this column, the editor of The Journal of Perinatal Education revisits Doris Haire's classic 1972 article, “The Cultural Warping of Childbirth,” and describes the birth culture of today. The editor also describes the contents of this issue, which offer a broad range of resources, research, and inspiration for childbirth educators in their efforts to promote normal birth.

  16. The "Mushroom Cloud" Demonstration Revisited

    ERIC Educational Resources Information Center

    Panzarasa, Guido; Sparnacci, Katia

    2013-01-01

    A revisitation of the classical "mushroom cloud" demonstration is described. Instead of aniline and benzoyl peroxide, the proposed reaction involves household chemicals such as alpha-pinene (turpentine oil) and trichloroisocyanuric acid ("Trichlor") giving an impressive demonstration of oxidation and combustion reactions that…

  17. Time rate collision matrix

    SciTech Connect

    Stoenescu, M.L.; Smith, T.M.

    1980-02-01

    The collision integral terms in Boltzmann equation are reformulated numerically leading to the substitution of the multiple integrals with a multiplicative matrix of the two colliding species velocity distribution functions which varies with the differential collision cross section. A matrix of lower rank may be constructed when one of the distribution functions is specified, in which case the matrix elements represent kinetic transition probabilities in the velocity space and the multiplication of the time rate collision matrix with the unknown velocity distribution function expresses the time rate of change of the distribution. The collision matrix may be used to describe the time evolution of systems in nonequilibrium conditions, to evaluate the rate of momentum and energy transfer between given species, or to generate validity criteria for linearized kinetic equations.

  18. Fiber-matrix integrity, micromorphology and flexural strength of glass fiber posts: Evaluation of the impact of rotary instruments.

    PubMed

    Pereira, Gabriel Kalil Rocha; Lançanova, Mateus; Wandscher, Vinicius Felipe; Kaizer, Osvaldo Bazzan; Limberger, Inácio; Özcan, Mutlu; Valandro, Luiz Felipe

    2015-08-01

    Several rotary instruments have been daily employed on clinic to promote cut aiming to adjust the length of fiber posts to the radicular conduct, but there is no information on the literature about the effects of the different rotary instruments and its impact on the micromorphology of surface and mechanical properties of the glass fiber post. This study aimed the impact of rotary instruments upon fiber-matrix integrity, micromorphology and flexural-strength of glass-fiber posts (GFP). GFP (N=110) were divided into 5 groups: Ctrl: as-received posts, DBc: coarse diamond-bur, DBff: extra-fine diamond-bur, CB: carbide-bur, DD: diamond-disc. Cutting procedures were performed under abundant irrigation. Posts exposed to rotary instruments were then subjected to 2-point inclined loading test (compression 45°) (n=10/group) and 3-point flexural-strength test (n=10/group). Fiber-matrix integrity and micromorphology at the cut surface were analyzed using a SEM (n=2/group). Cutting procedures did not significantly affect the 2-point (51.7±4.3-56.7±5.1 MPa) (p=0.0233) and 3-point flexural-strength (671.5±35.3-709.1±33.1 MPa) (p=0.0968) of the posts (One-way ANOVA and Tukey׳s test). Fiber detachment was observed only at the end point of the cut at the margins of the post. Cut surfaces of the CB group were smoother than those of the other groups. After 3-point flexural strength test, fiber-matrix separation was evident at the tensile side of the post. Rotary instruments tested with simultaneous water-cooling did not affect the resistance of the tested fiber posts but caused disintegration of the fibers from the matrix at the end of the cut, located at the margins. PMID:25955561

  19. Forest loss and the biodiversity threshold: an evaluation considering species habitat requirements and the use of matrix habitats.

    PubMed

    Estavillo, Candelaria; Pardini, Renata; da Rocha, Pedro Luís Bernardo

    2013-01-01

    Habitat loss is the main driver of the current biodiversity crisis, a landscape-scale process that affects the survival of spatially-structured populations. Although it is well-established that species responses to habitat loss can be abrupt, the existence of a biodiversity threshold is still the cause of much controversy in the literature and would require that most species respond similarly to the loss of native vegetation. Here we test the existence of a biodiversity threshold, i.e. an abrupt decline in species richness, with habitat loss. We draw on a spatially-replicated dataset on Atlantic forest small mammals, consisting of 16 sampling sites divided between forests and matrix habitats in each of five 3600-ha landscapes (varying from 5% to 45% forest cover), and on an a priori classification of species into habitat requirement categories (forest specialists, habitat generalists and open-area specialists). Forest specialists declined abruptly below 30% of forest cover, and spillover to the matrix occurred only in more forested landscapes. Generalists responded positively to landscape heterogeneity, peaking at intermediary levels of forest cover. Open area specialists dominated the matrix and did not spillover to forests. As a result of these distinct responses, we observed a biodiversity threshold for the small mammal community below 30% forest cover, and a peak in species richness just above this threshold. Our results highlight that cross habitat spillover may be asymmetrical and contingent on landscape context, occurring mainly from forests to the matrix and only in more forested landscapes. Moreover, they indicate the potential for biodiversity thresholds in human-modified landscapes, and the importance of landscape heterogeneity to biodiversity. Since forest loss affected not only the conservation value of forest patches, but also the potential for biodiversity-mediated services in anthropogenic habitats, our work indicates the importance of proactive

  20. Dynamic reciprocity revisited.

    PubMed

    Kaul, Himanshu; Ventikos, Yiannis

    2015-04-01

    The cellular microenvironment - which includes the cells, extracellular matrix (ECM), and local transport processes - affects the cell which in turn responds by synthetic or degradative processes causing the composition and the structure of ECM, and the local transport processes, to change which in a coupled manner influence the cell, and so forth. PMID:25636494

  1. Evaluation of a molecularly imprinted polymer for determination of steroids in goat milk by matrix solid phase dispersion.

    PubMed

    Gañán, Judith; Morante-Zarcero, Sonia; Gallego-Picó, Alejandrina; Garcinuño, Rosa María; Fernández-Hernando, Pilar; Sierra, Isabel

    2014-08-01

    A molecularly imprinted polymer-matrix solid-phase dispersion methodology for simultaneous determination of five steroids in goat milk samples was proposed. Factors affecting the extraction recovery such as sample/dispersant ratio and washing and elution solvents were investigated. The molecularly imprinted polymer used as dispersant in the matrix solid-phase dispersion procedure showed high affinity to steroids, and the obtained extracts were sufficiently cleaned to be directly analyzed. Analytical separation was performed by micellar electrokinetic chromatography using a capillary electrophoresis system equipped with a diode array detector. A background electrolyte composed of borate buffer (25mM, pH 9.3), sodium dodecyl sulfate (10mM) and acetonitrile (20%) was used. The developed MIP-MSPD methodology was applied for direct determination of testosterone (T), estrone (E1), 17β-estradiol (17β-E2), 17α-ethinylestradiol (EE2) and progesterone (P) in different goat milk samples. Mean recoveries obtained ranged from 81% to 110%, with relative standard deviations (RSD)≤12%. The molecularly imprinted polymer-matrix solid-phase dispersion method is fast, selective, cost-effective and environment-friendly compared with other pretreatment methods used for extraction of steroids in milk. PMID:24881547

  2. Electron heating in capacitively coupled plasmas revisited

    NASA Astrophysics Data System (ADS)

    Lafleur, T.; Chabert, P.; Booth, J. P.

    2014-06-01

    We revisit the problem of electron heating in capacitively coupled plasmas (CCPs), and propose a method for quantifying the level of collisionless and collisional heating in plasma simulations. The proposed procedure, based on the electron mechanical energy conservation equation, is demonstrated with particle-in-cell simulations of a number of single and multi-frequency CCPs operated in regimes of research and industrial interest. In almost all cases tested, the total electron heating is comprised of collisional (ohmic) and pressure heating parts. This latter collisionless component is in qualitative agreement with the mechanism of electron heating predicted from the recent re-evaluation of theoretical models. Finally, in very electrically asymmetric plasmas produced in multi-frequency discharges, we observe an additional collisionless heating mechanism associated with electron inertia.

  3. Formulation and in vitro evaluation of Eudragit S-100 coated naproxen matrix tablets for colon-targeted drug delivery system

    PubMed Central

    Mehta, Rohit; Chawla, Anuj; Sharma, Pooja; Pawar, Pravin

    2013-01-01

    The purpose of the present investigation was to prepare matrix tablets of naproxen using a hydrophobic polymer, i.e., Eudragit RLPO, RSPO, and combination of both, by wet granulation method. The tablets were further coated with different concentrations of Eudragit S-100, a pH-sensitive polymer, by dip immerse method. In vitro drug release studies of tablets were carried out in different dissolution media, i.e., 0.1 N HCl (pH 1.2), phosphate buffers pH 6.8 and 7.4, with or without rat cecal content. The swelling studies of the optimized formulation were carried out. The physicochemical parameters of all the formulations were found to be in compliance with the pharmacopoeial standards. The effect of dissolution medium on the surface of matrix tablet was determined by using Scanning Electron Microscopy technique. The stability studies of all formulations were performed as per ICH guidelines. The results demonstrated that the tablets coated with Eudragit S-100 (2% w/v) showed a sustained release of 94.67% for 24 h, but drug release increased to about 98.60% for 24 h in the presence of rat cecal content while the uncoated tablets released the drug within 5 h. With regard to release kinetics, the data were best fitted with the Higuchi model with non-Fickian drug release kinetics mechanism. The stability studies of tablets showed less degradation during accelerated and room temperature storage conditions for 6 months. The enteric-coated Eudragit S-100 coated matrix tablets of naproxen showed promising site-specific drug delivery in the colon region. PMID:23662280

  4. Dynamic Topography Revisited

    NASA Astrophysics Data System (ADS)

    Moresi, Louis

    2015-04-01

    Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The

  5. Matrix superpotentials

    NASA Astrophysics Data System (ADS)

    Nikitin, Anatoly G.; Karadzhov, Yuri

    2011-07-01

    We present a collection of matrix-valued shape invariant potentials which give rise to new exactly solvable problems of SUSY quantum mechanics. It includes all irreducible matrix superpotentials of the generic form W=kQ+\\frac{1}{k} R+P, where k is a variable parameter, Q is the unit matrix multiplied by a real-valued function of independent variable x, and P and R are the Hermitian matrices depending on x. In particular, we recover the Pron'ko-Stroganov 'matrix Coulomb potential' and all known scalar shape invariant potentials of SUSY quantum mechanics. In addition, five new shape invariant potentials are presented. Three of them admit a dual shape invariance, i.e. the related Hamiltonians can be factorized using two non-equivalent superpotentials. We find discrete spectrum and eigenvectors for the corresponding Schrödinger equations and prove that these eigenvectors are normalizable.

  6. Formulation development and optimization of sustained release matrix tablet of Itopride HCl by response surface methodology and its evaluation of release kinetics

    PubMed Central

    Bose, Anirbandeep; Wong, Tin Wui; Singh, Navjot

    2012-01-01

    The objective of this present investigation was to develop and formulate sustained release (SR) matrix tablets of Itopride HCl, by using different polymer combinations and fillers, to optimize by Central Composite Design response surface methodology for different drug release variables and to evaluate drug release pattern of the optimized product. Sustained release matrix tablets of various combinations were prepared with cellulose-based polymers: hydroxy propyl methyl cellulose (HPMC) and polyvinyl pyrolidine (pvp) and lactose as fillers. Study of pre-compression and post-compression parameters facilitated the screening of a formulation with best characteristics that underwent here optimization study by response surface methodology (Central Composite Design). The optimized tablet was further subjected to scanning electron microscopy to reveal its release pattern. The in vitro study revealed that combining of HPMC K100M (24.65 MG) with pvp(20 mg)and use of LACTOSE as filler sustained the action more than 12 h. The developed sustained release matrix tablet of improved efficacy can perform therapeutically better than a conventional tablet. PMID:23960836

  7. Evaluation of the availability of bound analyte for passive sampling in the presence of mobile binding matrix.

    PubMed

    Xu, Jianqiao; Huang, Shuyao; Jiang, Ruifen; Cui, Shufen; Luan, Tiangang; Chen, Guosheng; Qiu, Junlang; Cao, Chenyang; Zhu, Fang; Ouyang, Gangfeng

    2016-04-21

    Elucidating the availability of the bound analytes for the mass transfer through the diffusion boundary layers (DBLs) adjacent to passive samplers is important for understanding the passive sampling kinetics in complex samples, in which the lability factor of the bound analyte in the DBL is an important parameter. In this study, the mathematical expression of lability factor was deduced by assuming a pseudo-steady state during passive sampling, and the equation indicated that the lability factor was equal to the ratio of normalized concentration gradients between the bound and free analytes. Through the introduction of the mathematical expression of lability factor, the modified effective average diffusion coefficient was proven to be more suitable for describing the passive sampling kinetics in the presence of mobile binding matrixes. Thereafter, the lability factors of the bound polycyclic aromatic hydrocarbons (PAHs) with sodium dodecylsulphate (SDS) micelles as the binding matrixes were figured out according to the improved theory. The lability factors were observed to decrease with larger binding ratios and smaller micelle sizes, and were successfully used to predict the mass transfer efficiencies of PAHs through DBLs. This study would promote the understanding of the availability of bound analytes for passive sampling based on the theoretical improvements and experimental assessments. PMID:27026596

  8. UV-MALDI mass spectrometric quantitation of uracil based pesticides in fruit soft drinks along with matrix effects evaluation.

    PubMed

    Ivanova, Bojidarka; Spiteller, Michael

    2014-02-01

    This study focused on the development of the accurate and precise quantitative method for the determination of pesticides bromacil (1), terbacil (2), lenacil (3), butafenacil (4) and flupropacil (5) in fruit based soft drinks. Three different types of drinks are bought from market; huddled orange fruit drink (100%) (I), red-oranges (II) and multivitamin drink containing strawberry, orange, banana and maracuja (III). Samples were analyzed "with" and "without" pulp utilizing LC-ESI (or APCI) MS/MS, HPLC-ESI-(or APCI)-MS/MS and UV-MALDI-Orbitrap-MS methods. The effect of high complexity of the food matrix on the analysis was discussed. Study focuses on the advantages of the UV-MALDI-Orbitrap-MS method compared to the traditionally involved GC alone or hybrid methods such as GC-MS and LC-MS/MS for quantification of pesticides in water and soft drinks. The developed method included the techniques performed for validation, calibration and standardization. The target pesticides are widely used for the treatment of citrus fruits and pineapples, but for soft drink products, there are still no clear regulations on pesticide residues limits. The matrix effects in the analysis of fruit drinks required implementation of the exact standard reference material corresponds to the variety of food matrices. This paper contributed to the broad analytical implementation of the UV-MALDI-Orbitrap-MS method in the quality control and assessment programs for monitoring of pesticide contamination in fruit based sodas. PMID:24018142

  9. First Grade Writers Revisit Their Work

    ERIC Educational Resources Information Center

    Hansen, Jane A.

    2007-01-01

    In this article, the author focuses on first grade readers and writers who revisit their work and describes what first-graders do when they revisit their writing about science and literature and review collections of their work. The first-graders discussed here are in Elaine O'Connor's classroom at Clark Elementary School in Charlottesville. In a…

  10. Benjamin Franklin and Mesmerism, revisited.

    PubMed

    McConkey, Kevin M; Perry, Campbell

    2002-10-01

    The authors revisit and update their previous historiographical note (McConkey & Perry, 1985) on Benjamin Franklin's involvement with and investigation of animal magnetism or mesmerism. They incorporate more recent literature and offer additional comment about Franklin's role in and views about mesmerism. Franklin had a higher degree of personal involvement with and a more detailed opinion of mesmerism than has been previously appreciated. PMID:12362950