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1

Quantitative methods in archaeoseismology  

Microsoft Academic Search

Within the multidisciplinary field of archaeoseismology, quantitative methods have begun to be utilized more prevalently. This paper proposes a scheme of applying quantitative models to test the seismogenic hypothesis of observed damage and gives examples from field cases. The combination of 3D structural models of buildings or their remains based in part on phase shift laserscanner measurements combined with high-resolution

Klaus-G. Hinzen; Claus Fleischer; Sharon K. Reamer; Stephan Schreiber; Sven Schütte; Baris Yerli

2011-01-01

2

Quantitative impulse-thermography as non-destructive testing method in civil engineering – Experimental results and numerical simulations  

Microsoft Academic Search

Impulse-thermography is an active method for quantitative investigation of the near surface region of various structures which has recently been applied to civil engineering. It is well suited for the detection of voids and honeycombing in concrete up to concrete covers of 10cm and more. For quantitative analysis, a computer program for numerical simulation of the heating up and cooling

Ch. Maierhofer; A. Brink; M. Röllig; H. Wiggenhauser

2005-01-01

3

Quantitative Methods of Edge Detection.  

National Technical Information Service (NTIS)

Most local operators used in edge detection can be modelled by one of two methods: edge enhancement/thresholding and edge fitting. This dissertation presents a quantitative design and performance evaluation of these methods. The design techniques are base...

I. E. Abdou

1978-01-01

4

An adaptive method to record the track of a vehicle using map-matching result and quantitative fuzzy description  

NASA Astrophysics Data System (ADS)

For monitoring or tracking a vehicle locally or remotely, positioning information should be stored locally or transferred through wireless network timely. One of those key problems in such a system is to find an appropriate time-duration to update the position of the vehicle. If the time-duration is too small, too much positioning data will be stored locally or be transferred; but if the time duration is too big, the track cannot be recorded faithfully, and you can not identify the actual route the vehicle just went through. To resolve this problem, an adaptive method based on map-matching technology and fuzzy description is presented in this paper. Through running map-matching by comparing the vehicle's positioning information with road network geometrical and topological information in digital maps, a more precise position can be obtained and the current road can be identified. After that, the following factors are considered to detect whether the current position need be updated in center control unit: time duration, running distance, estimation error, the vehicle state changing, and running road changing. A deduction method is used to estimate and compare with the measured vehicle state. And a quantitative fuzzy description is used to describe the speed and angular speed of the vehicle. After that, an OR arithmetic logic computing unit is used to decide whether need update current position to center control unit. Finally, a test is given to evaluate this algorithm. The proposed adaptive algorithm can record the vehicle's track faithfully, and at the same time it decreases the communication cost between the mobile station and the center control unit.

Zhang, Xiaoguo; Guan, Xin; Zhang, Linxiang

2007-07-01

5

Quantitative Vs qualitative research methods  

Microsoft Academic Search

Quantitative methods have been widely used because of the fact that things that can be measured or counted gain scientific\\u000a credibility over the unmeasurable. But the extent of biological abnormality, severity, consequences and the impact of illness\\u000a cannot be satisfactorily captured and answered by the quantitative research alone. In such situations qualitative methods\\u000a take a holistic perspective preserving the complexities

M. Lakshman; Leena Sinha; Moumita Biswas; Maryann Charles; N. K. Arora

2000-01-01

6

Quantitative methods in nursing research.  

PubMed

This paper considers some of the general principles that are common to much of quantitative research in nursing. In particular, the role of hypothesis testing is considered, and the use of estimation is emphasized. Confidence intervals are advocated as a means of assessing both statistical and clinical significance. These principles and methods are illustrated using examples taken from the nursing literature. Finally, more complicated situations and the role of design are discussed. PMID:8732530

Abrams, K R; Scragg, A M

1996-05-01

7

PURPOSE RESULTS BACKGROUND METHODS RESULTS ...  

Center for Drug Evaluation (CDER)

Text Version... KETOCONAZOLE IN SUBJECTS WITH RENAL IMPAIRMENT (RI) TAKING RIVAROXABAN Ping Zhao, Joseph A. Grillo, Young-Moon Choi, Brian P ... More results from www.fda.gov/downloads/drugs/developmentapprovalprocess

8

The rise of quantitative methods in psychology  

Microsoft Academic Search

Quantitative methods have a long history in some scientific fields. Indeed, no one today would consider a qualitative data set in physics or a qualitative theory in chemistry. Quantitative methods are so central in these fields that they are often labelled \\

Denis Cousineau

2005-01-01

9

Quantitative method of medication system interface evaluation.  

PubMed

The objective of this study was to develop a quantitative method of evaluating the user interface for medication system software. A detailed task analysis provided a description of user goals and essential activity. A structural fault analysis was used to develop a detailed description of the system interface. Nurses experienced with use of the system under evaluation provided estimates of failure rates for each point in this simplified fault tree. Means of estimated failure rates provided quantitative data for fault analysis. Authors note that, although failures of steps in the program were frequent, participants reported numerous methods of working around these failures so that overall system failure was rare. However, frequent process failure can affect the time required for processing medications, making a system inefficient. This method of interface analysis, called Software Efficiency Evaluation and Fault Identification Method, provides quantitative information with which prototypes can be compared and problems within an interface identified. PMID:17625402

Pingenot, Alleene Anne; Shanteau, James; Pingenot, James D F

10

Photographic colorimetry as a quantitative cytochemical method  

Microsoft Academic Search

A method for quantitative cytophotometry based on the photographic method of Ornstein is described. Taking special precautions, photographic negatives are made of microscopic objects with light from the appropriate part of the spectrum. Enlarged prints, developed in a blue colour, are made from these negatives. Stirring with a stream of nitrogen was applied in this procedure.

E. M. DEN TONKELAAR; P. Duijn

1964-01-01

11

A quantitative method for measuring protein phosphorylation  

Microsoft Academic Search

We have developed a novel method for quantitating protein phosphorylation by a variety of protein kinases. It can be used with purified kinases and their substrates in vitro or in combination with cell extracts. The method is based on the knowledge that protein kinase C (PKC) adds three phosphates to each molecule of its preferred substrate, myelin basic protein (MBP).

J. Andres Mckenzie; Phyllis R. Strauss

2003-01-01

12

Method for quantitative estimation of thermal thresholds in patients  

Microsoft Academic Search

A quantitative method for the examination of thermal sensibility was applied in 26 normal subjects and in patients with various neurological disorders. The stimulation technique resembled Békésy audiometry: the patient reversed the direction of the temperature change of a thermode whenever warm, cold, or thermal pain thresholds were reached. The resulting temperature curve enables a quantitative description of the subject's

H Fruhstorfer; U Lindblom; W C Schmidt

1976-01-01

13

Quantitative measurement of vertigo frequency: preliminary results.  

PubMed

Persons who experience vertigo often describe their symptoms as a sensation of oscillations. Based on such a description, a pilot study was performed to determine if the frequency of the vertigo sensation could be quantified in a manner analogous to tone matching in tinnitus treatment. Fifteen subjects were tested using a virtual image system that consisted of a head mounted display showing a scene that oscillated horizontally or vertically at an adjustable frequency. Subjects were asked to adjust the direction and frequency to match their typical vertigo sensation. Results show that most persons with chronic vertigo had symptoms that could be realistically simulated by vection induced by the oscillating scene and that matched to a consistent specific frequency. They reported an average frequency of 1.09 Hz (range 0.27 to 3.3 Hz, SD 0.25). The large majority (13 out of 15) matched to a horizontal stimulus. Subjects that gave particularly high subjective ratings of the similarity of the motion sensation (7-8 out of 10) from the vection to their vertigo had lower frequency matches (average 0.61 +/- 0.25). Repeated measurements in 4 subjects 8 to 27 days later showed consistent results. This vertigo measurement technique may be used in the future to assess the ability of vestibular rehabilitation to reduce chronic vertigo. Identification of a specific frequency of chronic vertigo may be important in the specification of rehabilitation exercises. PMID:14646024

Zalewski-Zaragoza, Robert Aureo; Viirre, Erik Scott

2003-01-01

14

Quantitative laser-induced breakdown spectroscopy data using peak area step-wise regression analysis: an alternative method for interpretation of Mars science laboratory results  

SciTech Connect

The ChemCam instrument on the Mars Science Laboratory (MSL) will include a laser-induced breakdown spectrometer (LIBS) to quantify major and minor elemental compositions. The traditional analytical chemistry approach to calibration curves for these data regresses a single diagnostic peak area against concentration for each element. This approach contrasts with a new multivariate method in which elemental concentrations are predicted by step-wise multiple regression analysis based on areas of a specific set of diagnostic peaks for each element. The method is tested on LIBS data from igneous and metamorphosed rocks. Between 4 and 13 partial regression coefficients are needed to describe each elemental abundance accurately (i.e., with a regression line of R{sup 2} > 0.9995 for the relationship between predicted and measured elemental concentration) for all major and minor elements studied. Validation plots suggest that the method is limited at present by the small data set, and will work best for prediction of concentration when a wide variety of compositions and rock types has been analyzed.

Clegg, Samuel M [Los Alamos National Laboratory; Barefield, James E [Los Alamos National Laboratory; Wiens, Roger C [Los Alamos National Laboratory; Dyar, Melinda D [MT HOLYOKE COLLEGE; Schafer, Martha W [LSU; Tucker, Jonathan M [MT HOLYOKE COLLEGE

2008-01-01

15

Quantitative basin analysis methods and applications  

Microsoft Academic Search

Quantitative basin analysis has become increasingly important in petroleum exploration. Chapter 1 presents a quantitative basin analysis study from the Georges Bank Basin, East Coast of the USA. By applying a one-dimensional fluid flow\\/compaction model to the well data of the basin, the author obtains a quantitative understanding of the basin's geohistory, geothermal history, and hydrocarbon generation history so that

Jianchang

1990-01-01

16

Interlaboratory Comparison of Quantitative PCR Test Results for Dehalococcoides  

EPA Science Inventory

Quantitative PCR (qPCR) techniques have been widely used to measure Dehalococcoides (Dhc) DNA in the groundwater at field sites for several years. Interpretation of these data may be complicated when different laboratories using alternate methods conduct the analysis. An...

17

Alternative method for quantitative enzyme histochemistry of muscle fibers  

Microsoft Academic Search

The present study examines the use of photographic densitometry combined with atomic absorption spectrophotometry for the quantitation of enzyme activities (SDH and ATPase) in fresh frozen sections of rat tibialis anterior muscles. The technique eliminates some difficulties which are inherent in other methods. The reliability of the technique was found to be in the 98% range; the results were precise

D. W. Sickles; R. E. McLendon; Th. H. Rosenquist

1982-01-01

18

Reconcilable Differences: The Marriage of Qualitative and Quantitative Methods  

Microsoft Academic Search

Qualitative research consists of methods that allow for a more in-depth understanding of phe nomena and encompasses techniques such as focus groups, in-depth interviews, and participant observation. The guidelines that pertain to sampling and analysis are different from those which govern quantitative techniques, but they can be applied just as rigorously to ensure the validity of the results. This article

Paula N Goering; David L Streiner

1996-01-01

19

Quantitative analysis of fracture surface by roughness and fractal method  

SciTech Connect

In recent years there has been extensive research and great development in Quantitative Fractography, which acts as an integral part of fractographic analysis. A prominent technique for studying the fracture surface is based on fracture profile generation and the major means for characterizing the profile quantitatively are roughness and fractal methods. By this way, some quantitative indexes such as the roughness parameters R{sub L} for profile and R{sub S} for surface, fractal dimensions D{sub L} for profile and D{sub S} for surface can be measured. Given the relationships between the indexes and the mechanical properties of materials, it is possible to achieve the goal of protecting materials from fracture. But, as the case stands, the theory and experimental technology of quantitative fractography are still imperfect and remain to be studied further. Recently, Gokhale and Underwood et al have proposed an assumption-free method for estimating the surface roughness by vertically sectioning the fracture surface with sections at an angle of 120 deg with each other, which could be expressed as follows: R{sub S} = {ovr R{sub L}{center_dot}{Psi}} where {Psi} is the profile structure factor. This method is based on the classical sterological principles and verified with the aid of computer simulations for some ruled surfaces. The results are considered to be applicable to fracture surfaces with any arbitrary complexity and anisotropy. In order to extend the detail applications to this method in quantitative fractography, the authors made a study on roughness and fractal methods dependent on this method by performing quantitative measurements on some typical low-temperature impact fractures.

Li, X.W.; Tian, J.F.; Kang, Y.; Wang, Z.G. [Academia Sinica, Shenyang (China). State Key Lab. for Fatigue and Fracture of Materials

1995-09-01

20

Quantitative Methods for Evaluating Hospital Designs.  

National Technical Information Service (NTIS)

The study provides an integrated quantitative-qualitative basis for decisions involving the relative locations of functions, and hence facilities, within the individual short-term, general, voluntary hospital. The approach used in attacking the problem wa...

G. L. Delon H. E. Smalley

1970-01-01

21

Method of quantitating dsDNA  

DOEpatents

A method for quantitating dsDNA in an aqueous sample solution containing an unknown amount of dsDNA. A first aqueous test solution containing a known amount of a fluorescent dye-dsDNA complex and at least one fluorescence-attenutating contaminant is prepared. The fluorescence intensity of the test solution is measured. The first test solution is diluted by a known amount to provide a second test solution having a known concentration of dsDNA. The fluorescence intensity of the second test solution is measured. Additional diluted test solutions are similarly prepared until a sufficiently dilute test solution having a known amount of dsDNA is prepared that has a fluorescence intensity that is not attenuated upon further dilution. The value of the maximum absorbance of this solution between 200-900 nanometers (nm), referred to herein as the threshold absorbance, is measured. A sample solution having an unknown amount of dsDNA and an absorbance identical to that of the sufficiently dilute test solution at the same chosen wavelength is prepared. Dye is then added to the sample solution to form the fluorescent dye-dsDNA-complex, after which the fluorescence intensity of the sample solution is measured and the quantity of dsDNA in the sample solution is determined. Once the threshold absorbance of a sample solution obtained from a particular environment has been determined, any similarly prepared sample solution taken from a similar environment and having the same value for the threshold absorbance can be quantified for dsDNA by adding a large excess of dye to the sample solution and measuring its fluorescence intensity.

Stark, Peter C. (Los Alamos, NM); Kuske, Cheryl R. (Los Alamos, NM); Mullen, Kenneth I. (Los Alamos, NM)

2002-01-01

22

ASSESSING QUANTITATIVE RESULTS IN ACCRETION SIMULATIONS: FROM LOCAL TO GLOBAL  

SciTech Connect

Discretized numerical simulations are a powerful tool for the investigation of nonlinear MHD turbulence in accretion disks. However, confidence in their quantitative predictions requires a demonstration that further refinement of the spatial grid scale would not result in any significant change. This has yet to be accomplished, particularly for global disk simulations. In this paper, we combine data from previously published stratified shearing box simulations and new global disk simulations to calibrate several quantitative diagnostics by which one can estimate progress toward numerical convergence of the magnetic field. Using these diagnostics, we find that the established criterion for an adequate numerical description of linear growth of the magneto-rotational instability (the number of cells across a wavelength of the fastest-growing vertical wavenumber mode) can be extended to a criterion for the adequate description of nonlinear MHD disk turbulence, but the standard required is more stringent. We also find that azimuthal resolution, which has received little attention in previous studies, can significantly affect the evolution of the poloidal magnetic field. We further analyze the comparative resolution requirements of a small sample of initial magnetic field geometries; not surprisingly, more complicated initial field geometries require higher spatial resolution. Otherwise, they tend to evolve to qualitatively similar states if evolved for sufficient time. Applying our quantitative resolution criteria to a sample of previously published global simulations, we find that, with perhaps a single exception, they are significantly underresolved, and therefore underestimate the magnetic turbulence and resulting stress levels throughout the accretion flow.

Hawley, John F.; Guan Xiaoyue [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Krolik, Julian H., E-mail: jh8h@virginia.edu, E-mail: xg3z@virginia.edu, E-mail: jhk@pha.jhu.edu [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

2011-09-01

23

Meaning in Method: The Rhetoric of Quantitative and Qualitative Research  

Microsoft Academic Search

The current debate about quantitative and qualitative methods focuses on whether there is a necessary connection between method-type and research paradigm that makes the different approaches incompatible. This paper argues that part of the connection is rhetorical. Quantitative methods express the assumptions of a positvisit paradigm which holds that behavior can be explained through objective facts. Design and instrumentation persuade

WILLIAM A. FIRESTONE

1987-01-01

24

Validation of a quantitative method for real time PCR kinetics  

Microsoft Academic Search

Real time RT-PCR is the most sensitive method for quantitation of gene expression levels. The accuracy can be dependent on the mathematical model on which the quantitative methods are based. The generally accepted mathematical model assumes that amplification efficiencies are equal at the exponential phase of the reactions for the same amplicon. However, no methods are available to test the

Weihong Liu; David A. Saint

2002-01-01

25

Quantitative methods for ecological network analysi  

Microsoft Academic Search

The analysis of networks of ecological trophic transfers is a useful complement to simulation modeling in the quest for understanding whole-ecosystem dynamics. Trophic networks can be studied in quantitative and systematic fashion at several levels. Indirect relationships between any two individual taxa in an ecosystem, which often differ in either nature or magnitude from their direct influences, can be assayed

Robert E. Ulanowicz

2004-01-01

26

Quantitative and qualitative decision-making methods in simulation modelling  

Microsoft Academic Search

Discrete event simulation (DES) is widely known to be a quantitative research tool. A simulation modelling process is mainly based on feeding quantitative data into a model to produce quantitative results in a structured sequential process. Qualitative approaches to research take a less structured approach with more of an inclination towards judgmental and expert knowledge rather than hard data. In

Tillal Eldabi; Zahir Irani; Ray J. Paul; Peter E. D. Love

2002-01-01

27

A quantitative method for determining the robustness of complex networks  

NASA Astrophysics Data System (ADS)

Most current studies estimate the invulnerability of complex networks using a qualitative method that analyzes the decay rate of network performance. This method results in confusion over the invulnerability of various types of complex networks. By normalizing network performance and defining a baseline, this paper defines the invulnerability index as the integral of the normalized network performance curve minus the baseline. This quantitative method seeks to measure network invulnerability under both edge and node attacks and provides a definition on the distinguishment of the robustness and fragility of networks. To demonstrate the proposed method, three small-world networks were selected as test beds. The simulation results indicate that the proposed invulnerability index can effectively and accurately quantify network resilience and can deal with both the node and edge attacks. The index can provide a valuable reference for determining network invulnerability in future research.

Qin, Jun; Wu, Hongrun; Tong, Xiaonian; Zheng, Bojin

2013-06-01

28

Advancing the study of violence against women using mixed methods: integrating qualitative methods into a quantitative research program.  

PubMed

A mixed methods approach, combining quantitative with qualitative data methods and analysis, offers a promising means of advancing the study of violence. Integrating semi-structured interviews and qualitative analysis into a quantitative program of research on women's sexual victimization has resulted in valuable scientific insight and generation of novel hypotheses for testing. This mixed methods approach is described and recommendations for integrating qualitative data into quantitative research are provided. PMID:21307032

Testa, Maria; Livingston, Jennifer A; VanZile-Tamsen, Carol

2011-02-01

29

A quantitative method for optimized placement of continuous air monitors.  

PubMed

Alarming continuous air monitors (CAMs) are a critical component for worker protection in facilities that handle large amounts of hazardous materials. In nuclear facilities, continuous air monitors alarm when levels of airborne radioactive materials exceed alarm thresholds, thus prompting workers to exit the room to reduce inhalation exposures. To maintain a high level of worker protection, continuous air monitors are required to detect radioactive aerosol clouds quickly and with good sensitivity. This requires that there are sufficient numbers of continuous air monitors in a room and that they are well positioned. Yet there are no published methodologies to quantitatively determine the optimal number and placement of continuous air monitors in a room. The goal of this study was to develop and test an approach to quantitatively determine optimal number and placement of continuous air monitors in a room. The method we have developed uses tracer aerosol releases (to simulate accidental releases) and the measurement of the temporal and spatial aspects of the dispersion of the tracer aerosol through the room. The aerosol dispersion data is then analyzed to optimize continuous air monitor utilization based on simulated worker exposure. This method was tested in a room within a Department of Energy operated plutonium facility at the Savannah River Site in South Carolina, U.S. Results from this study show that the value of quantitative airflow and aerosol dispersion studies is significant and that worker protection can be significantly improved while balancing the costs associated with CAM programs. PMID:14571993

Whicker, Jeffrey J; Rodgers, John C; Moxley, John S

2003-11-01

30

[Instruments for quantitative methods of nursing research].  

PubMed

Instruments for quantitative nursing research are a mean to objectify and measure a variable or a phenomenon in the scientific research. There are direct instruments to measure concrete variables and indirect instruments to measure abstract concepts (Burns, Grove, 1997). Indirect instruments measure the attributes by which a concept is made of. Furthermore, there are instruments for physiologic variables (e.g. for the weight), observational instruments (Check-lists e Rating Scales), interviews, questionnaires, diaries and the scales (Check-lists, Rating Scales, Likert Scales, Semantic Differential Scales e Visual Anologue Scales). The choice to select an instrument or another one depends on the research question and design. Instruments research are very useful in research both to describe the variables and to see statistical significant relationships. Very carefully should be their use in the clinical practice for diagnostic assessment. PMID:11228871

Vellone, E

31

Correlation of qualitative and quantitative results from testing respirator fit  

SciTech Connect

Three qualitative respirator fit tests were evaluated for their ability to measure respiratory protection adequately. The methods were the negative pressure test, the isoamyl acetate test, and the irritant smoke test. Each test was performed concurrently with a single qualitative fit test, the dioctylphthalate (DOP) test, during 274 half-mask and 274 full face piece wearings. Most (95%) of the tested study had adequately fitting respirators as determined by quantitative testing. Of these subjects, 96-100% passed the qualitative fit tests. Of the 5% of the study subjects with inadequately fitting half-mask respirators, 93-100% of the inadequate fits were detected by qualitative methods. Twenty-three to 46% of the poorly fitting full face masks were detected by qualitative methods. The probability of passing or failing a qualitative test with an inadequately fitting respirator can be estimated; however, the uncertainty associated with each estimate is largely due to the small number of study subjects with poorly fitting respirators.

Hardis, K.E.

1983-02-01

32

The Bradford Method for Protein Quantitation  

Microsoft Academic Search

\\u000a A rapid and accurate method for the estimation of protein concentration is essential in many fields of protein study. An assay\\u000a originally described by Bradford (1) has become the preferred method for quantifying protein in many laboratories. This technique is simpler, faster, and more\\u000a sensitive than the Lowry method. Moreover, when compared with the Lowry method, it is subject to

Nicholas J. Kruger

33

Photographic colorimetry as a quantitative cytochemical method  

Microsoft Academic Search

The amount of absorbance in a number of Feulgen-stained chicken erythrocytes and bull spermatozoa was measured by two independent methods, namely photographic colorimetry and scanning cytophotometry. With both methods the amount of DNA was found to be highly constant in these objects. Both methods revealed a highly significant variation between nuclei of about 5 per cent. At this level however

E. M. Tonkelaar; P. VAN DUIJN

1964-01-01

34

An Uneasy Alliance: Combining Qualitative and Quantitative Research Methods  

Microsoft Academic Search

The paper describes the difficulties encountered in trying to combine qualitative and quantitative research methods in a study of the relationship between moral reasoning and teenage drug use. Four problems that arose in the attempt to reduce qualitative data to a quantitative format are described. These problems are: (1) making analytic sense of singular responses; (2) a mistaken logical inference

David R. Buchanan

1992-01-01

35

Quantitative methods for ecological network analysis.  

PubMed

The analysis of networks of ecological trophic transfers is a useful complement to simulation modeling in the quest for understanding whole-ecosystem dynamics. Trophic networks can be studied in quantitative and systematic fashion at several levels. Indirect relationships between any two individual taxa in an ecosystem, which often differ in either nature or magnitude from their direct influences, can be assayed using techniques from linear algebra. The same mathematics can also be employed to ascertain where along the trophic continuum any individual taxon is operating, or to map the web of connections into a virtual linear chain that summarizes trophodynamic performance by the system. Backtracking algorithms with pruning have been written which identify pathways for the recycle of materials and energy within the system. The pattern of such cycling often reveals modes of control or types of functions exhibited by various groups of taxa. The performance of the system as a whole at processing material and energy can be quantified using information theory. In particular, the complexity of process interactions can be parsed into separate terms that distinguish organized, efficient performance from the capacity for further development and recovery from disturbance. Finally, the sensitivities of the information-theoretic system indices appear to identify the dynamical bottlenecks in ecosystem functioning. PMID:15556474

Ulanowicz, Robert E

2004-12-01

36

New method of quantitatively describing drainage areas  

Microsoft Academic Search

The aim was to introduce a new method, the DAZ method (drainage area zonation), to quantify environmental parameters, such as bedrocks, soil type, and land use in drainage areas. The work was carried out within the framework of the Swedish project “Liming—mercury.” Two important points in the project are that there are quantifiable relationships between the character of the drainage

Lars Håkanson; Tord Andersson; Ake Nilsson

1990-01-01

37

New method of quantitatively describing drainage areas  

Microsoft Academic Search

The aim was to introduce a new method, the DAZ method (drainage area zonation), to quantify environmental parameters, such as bedrocks, soil type, and land use in drainage areas. The work was carried out within the framework of the Swedish project Liming--mercury. Two important points in the project are that there are quantifiable relationships between the character of the drainage

L. Hakanson; T. Andersson; A. Nilsson

2009-01-01

38

Quantitative ultrasonic methods for characterization of skin lesions in vivo.  

PubMed

Quantitative ultrasonic methods were studied for characterizing skin lesions in vivo using contact dermatitis as an example. The parameters studied include skin thickness, echogenicity, attenuation coefficient slope and parameters related to echo statistics (signal-to-noise ratio and shape parameters of Weibull, K and generalized gamma distributions). Data were collected using a high-frequency ultrasound (US) system (center frequency = 33 MHz). To compensate for depth-dependent diffraction effects, correction curves as a function of the distance between the transducer and the tissue were first empirically obtained. Diffraction-corrected quantitative parameters were then compared between healthy and affected skin of volunteers, who underwent patch testing for allergic and irritant contact dermatitis. A significant increase in skin thickness, decrease in echogenicity of the upper dermis and decrease in attenuation coefficient slope were found at the affected sites compared to those of healthy skin. However, no differences in parameters related to the echo statistics of the mid-dermis were found. These results indicate that a combination of quantitative ultrasonic parameters have the potential for extracting information for characterizing skin conditions. PMID:12837498

Raju, Balasundar I; Swindells, Kirsty J; Gonzalez, Salvador; Srinivasan, Mandayam A

2003-06-01

39

Quantitative infrared analysis of borophosphosilicate films using multivariate statistical methods  

SciTech Connect

Infrared (IR) spectroscopy can serve as a rapid method for the quantitative analysis of borophosphosilicate glass (BPSG) films on Si wafers for the microelectronics industry. The advantages of using statistically designed calibration sets are emphasized. Classical least-squares (CLS), partial least-squares (PLS), and principal component regression (PCR) methods are all found to provide improved precision over traditional peak-height measurements. The quantitative results from spectral measurements taken in transmission mode at both 0/sup 0/ and 60/sup 0/ incident angles were also compared. PLS and PCR methods yielded results that were comparable within the sampling error, and each exhibited a better analysis precision than that obtained from the CLS analysis. Both PLS and PCR methods yielded the best results when applied to the original 60/sup 0/ incident angle data, which was not corrected for film thickness. PLS and PCR analyses each gave a standard error of prediction (SEP) for boron of approx. = 0.1 wt% and approx. = 0.2 wt % for phosphorus for a set of 44 calibration samples which spanned a range of concentrations from 1 to 5 wt % B and 2 to 6 wt % P. The PLS and PCR methods applied to the IR spectra were also capable of monitoring film thickness with a SEP of 14 nm for films that varied in thickness from 430 to 1000 nm. The importance of using these full-spectrum multivariate methods for outlier sample detection is presented, and the ability to extract qualitative spectral information from the CLS and PLS calibrations is demonstrated.

Haaland, D.M.

1988-06-01

40

New method of quantitatively describing drainage areas  

NASA Astrophysics Data System (ADS)

The aim was to introduce a new method, the DAZ method (drainage area zonation), to quantify environmental parameters, such as bedrocks, soil type, and land use in drainage areas. The work was carried out within the framework of the Swedish project “Liming—mercury.” Two important points in the project are that there are quantifiable relationships between the character of the drainage area and the lake and that several limnological and morphometric parameters may have an impact on the Hg content in fish. The DAZ method accounts for the fact that, for example, a certain soil type does not have an even distribution in the whole drainage area. To get a simple yet relevant measure of the influence of, for example, soil type on the lake character, the drainage areas were divided into zones using a special transparent paper placed on the map. The method gives normalized values depending on: (1) distance between the object and the given lake, (2) the main direction of water flow in the drainage area, and (3) the area of the environmental parameter (for example, area of bedrock). In the DAZ method, dot counting is used for determination of area. The dot-counting method has been compared with other methods for area determination (planimeter and square counting). Dot counting is the fastest and the counting of squares the most time consuming. The statistical reliabilities of the dot method and the planimeter method were compared. The planimeter is best for large homogeneous objects. Dot counting, on the other hand, is very well suited for heterogeneous objects. The statistical certainty of area determination depends on size, heterogeneity, and form of the objects, as well as the time dedicated to the determination. A nomogram is also given, which illustrates the relationship between the number of counts, that is, the number of times the transparent dotted paper is put on the map and the dots counted, the error in the area determination, and the statistical reliability.

Håkanson, Lars; Andersson, Tord; Nilsson, Ake

1990-01-01

41

The Lowry Method for Protein Quantitation  

Microsoft Academic Search

\\u000a The most accurate method of determining protein concentration is probably acid hydrolysis followed by amino acid analysis.\\u000a Most other methods are sensitive to the amino acid composition of the protein, and absolute concentrations cannot be obtained.\\u000a The procedure of Lowry et al. (1) is no exception, but its sensitivity is moderately constant from protein to protein, and it has been

Jakob H. Waterborg; Harry R. Matthews

42

A quantitative method for blood lipoproteins using cellulose acetate electrophoresis  

PubMed Central

A rapid, inexpensive, and quantitative method is described for obtaining the levels of plasma very low, low, and high density lipoproteins using cellulose acetate electrophoresis and lipid assays without prior separation by ultracentrifuge or other techniques. It involves separation of the lipoproteins by cellulose acetate electrophoresis, followed by their identification with the ozone-Schiff reaction. The total lipoprotein concentration is estimated from the total plasma phospholipid, and the percentage of each component obtained by densitometric analysis of the stained electrophoretograms, using reflected light. For samples with a raised level of very low density lipoprotein, plasma triglyceride analysis is also required. The results obtained by the cellulose acetate electrophoresis method are in good agreement with those by the analytical ultracentrifuge and the preparative ultracentrifuge with refractometry. The theoretical assumptions on which the method is based have been shown to be valid. Images

Magnani, H. N.; Howard, A. N.

1971-01-01

43

Critical temperature: A quantitative method of assessing cold tolerance  

Treesearch

Title: Critical temperature: A quantitative method of assessing cold tolerance ... page and attach it to the printout of the article, to retain the full citation information . ... Check the Northern Research Station web site to request a printed copy of this ...

44

Indirect scaling methods for testing quantitative emotion theories.  

PubMed

Two studies investigated the utility of indirect scaling methods, based on graded pair comparisons, for the testing of quantitative emotion theories. In Study 1, we measured the intensity of relief and disappointment caused by lottery outcomes, and in Study 2, the intensity of disgust evoked by pictures, using both direct intensity ratings and graded pair comparisons. The stimuli were systematically constructed to reflect variables expected to influence the intensity of the emotions according to theoretical models of relief/disappointment and disgust, respectively. Two probabilistic scaling methods were used to estimate scale values from the pair comparison judgements: Additive functional measurement (AFM) and maximum likelihood difference scaling (MLDS). The emotion models were fitted to the direct and indirect intensity measurements using nonlinear regression (Study 1) and analysis of variance (Study 2). Both studies found substantially improved fits of the emotion models for the indirectly determined emotion intensities, with their advantage being evident particularly at the level of individual participants. The results suggest that indirect scaling methods yield more precise measurements of emotion intensity than rating scales and thereby provide stronger tests of emotion theories in general and quantitative emotion theories in particular. PMID:23650936

Junge, Martin; Reisenzein, Rainer

2013-05-07

45

Fluorometric method of quantitative cell mutagenesis  

DOEpatents

A method for assaying a cell culture for mutagenesis is described. A cell culture is stained first with a histochemical stain, and then a fluorescent stain. Normal cells in the culture are stained by both the histochemical and fluorescent stains, while abnormal cells are stained only by the fluorescent stain. The two stains are chosen so that the histochemical stain absorbs the wavelengths that the fluorescent stain emits. After the counterstained culture is subjected to exciting light, the fluorescence from the abnormal cells is detected.

Dolbeare, F.A.

1980-12-12

46

Fluorometric method of quantitative cell mutagenesis  

DOEpatents

A method for assaying a cell culture for mutagenesis is described. A cell culture is stained first with a histochemical stain, and then a fluorescent stain. Normal cells in the culture are stained by both the histochemical and fluorescent stains, while abnormal cells are stained only by the fluorescent stain. The two stains are chosen so that the histochemical stain absorbs the wavelengths that the fluorescent stain emits. After the counterstained culture is subjected to exciting light, the fluorescence from the abnormal cells is detected.

Dolbeare, Frank A. (Livermore, CA)

1982-01-01

47

Fluorometric method of quantitative cell mutagenesis  

SciTech Connect

A method for assaying a cell culture for mutagenesis is described. A cell culture is stained first with a histochemical stain, and then a fluorescent stain. Normal cells in the culture are stained by both the histochemical and fluorescent stains, while abnormal cells are stained only by the fluorescent stain. The two stains are chosen so that the histochemical stain absorbs the wavelengths that the fluorescent stain emits. After the counterstained culture is subjected to exciting light, the fluorescence from the abnormal cells is detected.

Dolbeare, F.A.

1982-08-17

48

Exploring quantitative methods for evaluation of lip function.  

PubMed

The objective was to explore quantitative methods for the measurement of lip mobility and lip force and to relate these to qualitative assessments of lip function. Fifty healthy adults (mean age 45 years) and 23 adults with diagnoses affecting the facial muscles (mean age 37 years) participated in the study. Diagnoses were Möbius syndrome (n=5), Facioscapulohumeral muscular dystrophy (n=6) and Myotonic dystrophy type 1 (n=12). A system for computerised 3D analysis of lip mobility and a lip force meter were tested, and the results were related to results from qualitative assessments of lip mobility, speech (articulation), eating ability and saliva control. Facial expressions studied were open mouth smile and lip pucker. Normative data and cut-off values for adults on lip mobility and lip force were proposed, and the diagnostic value of these thresholds was tested. The proposed cut-off values could identify all inviduals with moderate or severe impairment of lip mobility but not always the milder cases. There were significant correlations between the results from quantitative measurements and qualitative assessments. The examined instruments for measuring lip function were found to be reliable with an acceptable measuring error. The combination of quantitative and qualitative ways to evaluate lip function made it possible to show the strong relation between lip contraction, lip force, eating ability and saliva control. The same combination of assessments can be used in the future to study if oral motor exercises aimed at improving lip mobility and strength could have a positive effect on lip function. PMID:20969612

Sjögreen, L; Lohmander, A; Kiliaridis, S

2010-10-23

49

Quantitative imaging of corrosion in plates by eddy current methods  

SciTech Connect

The authors consider the problem of determining material loss due to corrosion in a plate. Eddy current data are collected on one side of the plate with corrosion damage occurring on the opposite side. The work is based on linearizing the relationship between eddy current loop impedance change with the loss profile. In this context, the authors show that eddy current data are sufficient to uniquely determine the material loss profile. Because of the ill posedness of the reconstruction problem, they propose three regularization strategies in devising computational methods. Numerical results using consistent data, and with added noise, indicate that the computational methods are quite capable of obtaining accurate quantitative estimates of the loss profile.

Luong, B. [Univ. of Delaware, Newark, DE (United States). Dept. of Mathematical Science; Santosa, F. [Univ. of Minnesota, Minneapolis, MN (United States). School of Mathematics

1998-10-01

50

VLF method: elimination of noises and quantitative interpretation  

Microsoft Academic Search

Geophysical investigations by the very low frequency method are greatly complicated by time variations and the rugged-relief effect. For elimination of these noises effective statistical procedures have been developed. Quantitative interpretation of VLF anomalies under difficult geological conditions can be conducted with modified methods, developed in magnetic prospecting. Over complex geological sections interpretation of the method's integration can be conducted

L. V. Eppelbaum; B. E. Khesin

1992-01-01

51

Quantitative methods of measuring restorative components in urban public parks  

Microsoft Academic Search

The paper demonstrates how quantitative methods can be used in a landscape architecture study. Three different methods to determine how people evaluate the psychological restoration\\/relaxation potential of small urban parks, as described in attention restoration theory, were assessed. The methods presented and evaluated are: ratings of environments based on quantified photos, eye tracking and choice-based conjoint analysis. Ratings of environments

Helena Nordh

2012-01-01

52

Food safety regulation, economic impact assessment and quantitative methods  

Microsoft Academic Search

Together with a call for more efficient regulations in the EU, there is a growing demand for transparency in the evaluation techniques to assess and predict their effects. This article explores the potential impacts of food safety regulations and discusses the quantitative methods used in the policy evaluation literature. Along with the strengths and limitations of each method, this review

Maddalena Ragona; Mario Mazzocchi

2008-01-01

53

Quantitative analysis of human immunoregulatory cytokines by electrochemiluminescence method.  

PubMed

Quantitative analysis of human immunoregulatory cytokines in physiological media and cell cultures plays an important role in fundamental and clinical research. Here we describe the quantification of interleukin (IL)-2, IL-4, IL-10 and interferon-gamma (IFN-gamma) in human serum and peripheral blood mononuclear cell (PBMC)-conditioned medium by electrochemiluminescence method (ECL). We demonstrate that this approach allows to detect cytokine concentration from 1 pg/ml. The high sensitivity in combination with accuracy and wide range of determined concentration indicates that ECL meets the standards of quantitative analysis of cytokines. Simplicity and short time of procedure, small assay volume and high reproducibility make ECL method competitive in practical use with conventional quantitative methods of cytokine detection. PMID:12667672

Sennikov, Sergey V; Krysov, Sergey V; Injelevskaya, Tatiana V; Silkov, Alexandr N; Grishina, Lyubov V; Kozlov, Vladimir A

2003-04-01

54

Correlation of quantitative risk results for high hazard processes.  

PubMed

A quantitative risk analysis was conducted to evaluate the design of the VX neutralization subsystem and related support facilities of the U.S. Army Newport Chemical Agent Disposal Facility. Three major incidents including agent release, personnel injury, and system loss were studied using fault tree analysis methodology. Each incident was assigned a risk assessment code based on the severity level and probability of occurrence of the incident. Safety mitigations or design changes were recommended to bring the "undesired" risk level (typical agent release events) to be "acceptable with controls" or "acceptable." PMID:12969409

Wang, Yanjun; West, Harry H; Teague, Tom L; Hasan, Najmul; Mannan, M Sam

2003-10-01

55

a Method for Quantitative Measurement by Thermal Neutron Radiography  

Microsoft Academic Search

A quantitative measurement method by thermal neutron radiography was proposed for two-dimensional void fraction measurement in two-phase flow. The umbra method was modified for two-dimensional measurement by using a neutron absorber grid. Image processing methods to compensate for the effects of neutrons scattered in the object and optical rays scattered in camera were developed. A step made from acrylic resin

N. Takenaka; H. Asano; T. Fujii; M. Matsubayashi

2001-01-01

56

Teaching nursing research. Integrating quantitative and qualitative methods.  

PubMed

In the belief that graduate nursing students should be able to analyze, evaluate, and critique both qualitative and quantitative research methods and should be able to design their own research projects, two faculty members developed a two-course sequence integrating the two methods. The authors, each an expert in one of the methods, describe how they designed and co-taught these innovative courses. PMID:10876529

Lehna, C; Pfoutz, S

57

Trojan Horse Method: Recent Results  

SciTech Connect

Owing the presence of the Coulomb barrier at astrophysically relevant kinetic energies, it is very difficult, or sometimes impossible to measure astrophysical reaction rates in laboratory. This is why different indirect techniques are being used along with direct measurements. The THM is unique indirect technique allowing one measure astrophysical rearrangement reactions down to astrophysical relevant energies. The basic principle and a review of the main application of the Trojan Horse Method are presented. The applications aiming at the extraction of the bare S{sub b}(E) astrophysical factor and electron screening potentials U{sub e} for several two body processes are discussed.

Pizzone, R. G.; Spitaleri, C. [Dipartimento di Metodologie Fisiche e Chimiche per l'Ingegneria, Universita di Catania and Laboratori Nazionali del Sud-INFN, Catania (Italy)

2008-01-24

58

The APEX Quantitative Proteomics Tool: Generating protein quantitation estimates from LCMS\\/MS proteomics results  

Microsoft Academic Search

BACKGROUND: Mass spectrometry (MS) based label-free protein quantitation has mainly focused on analysis of ion peak heights and peptide spectral counts. Most analyses of tandem mass spectrometry (MS\\/MS) data begin with an enzymatic digestion of a complex protein mixture to generate smaller peptides that can be separated and identified by an MS\\/MS instrument. Peptide spectral counting techniques attempt to quantify

John C. Braisted; Srilatha Kuntumalla; Christine Vogel; Edward M. Marcotte; Alan R. Rodrigues; Rong Wang; Shih-ting Huang; Erik S. Ferlanti; Alexander I. Saeed; Robert D. Fleischmann; Scott N. Peterson; Rembert Pieper

2008-01-01

59

Quantitative estimation method for discrimination of nuance among impression words  

Microsoft Academic Search

In this paper the authors discuss a quantitative estimation method for discrimination of nuance among impression words that express favor, impression feeling, emotion, or aesthetic sense. The impression words play the role of keywords on information retrieval for the database of fine arts or industrial design. The subtle discrimination among the nuance of impression words makes verbal expression of our

S. Taka Gi; Y. Isomoto; H. Nozaki

2000-01-01

60

Novel quantitative non-destructive testing method for composite structures  

Microsoft Academic Search

A novel QNDT (quantitative non-destructive testing) method is developed that is combined with a phase-shifting shearing speckle and thermograph, and, it aims at the detection of faults such as cracks, voids, delamination and weak areas. The technique is immune to ambient noise and is suitable for measuring the in situ environment. Some different depth defects that would produce deformation differing

Jin-long Chen; Yu-wen Qin; Hong-wei Ji; Xin-hua Ji

1998-01-01

61

A quantitative cytochemical method for measuring carbonic anhydrase activity  

Microsoft Academic Search

Synopsis  Components of a histochemical method for demonstrating carbonic anhydrase activity have been investigated quantitatively. It was found that it is not necessary to use free-floating sections provided the reaction is done in a reaction medium of controlled depth. This permits the use of normal cryostat sections on glass slides, so making this technique applicable to the cytochemical bioassay of gastrin.

Nigel Loveridge; Bute Gardens

1978-01-01

62

Simple laboratory methods for quantitative IR measurements of CW agents  

NASA Astrophysics Data System (ADS)

A simple method is presented for quantitatively measuring the absorbance of chemical warfare (CW) agents and their simulants in the vapour phase. The technique is based on a standard lab-bench FTIR spectrometer, 10-cm gas cell, a high accuracy Baratron pressure manometer, vacuum pump and simple stainless-steel hardware components. The results of this measurement technique are demonstrated for sarin (GB) and soman (GD). A second technique is also introduced for the passive IR detection of CW agents in an open- air path located in a fumehood. Using a modified open-cell with a pathlength of 45 cm, open-air passive infrared measurements have been obtained for simulants and several classical CW agents. Detection, identification and quantification results based on passive infrared measurements are presented for GB and the CW agent simulant, DMMP, using the CATSI sensor which has been developed by DRDC Valcartier. The open-cell technique represents a relatively simple and feasible method for examining the detection capability of passive sensors, such as CATSI, for CW agents.

Puckrin, Eldon; Thériault, Jean-Marc; Lavoie, Hugo; Dubé, Denis; Lepage, Carmela J.; Petryk, Michael

2005-11-01

63

A new mapping method for quantitative trait loci of silkworm  

PubMed Central

Background Silkworm is the basis of sericultural industry and the model organism in insect genetics study. Mapping quantitative trait loci (QTLs) underlying economically important traits of silkworm is of high significance for promoting the silkworm molecular breeding and advancing our knowledge on genetic architecture of the Lepidoptera. Yet, the currently used mapping methods are not well suitable for silkworm, because of ignoring the recombination difference in meiosis between two sexes. Results A mixed linear model including QTL main effects, epistatic effects, and QTL × sex interaction effects was proposed for mapping QTLs in an F2 population of silkworm. The number and positions of QTLs were determined by F-test and model selection. The Markov chain Monte Carlo (MCMC) algorithm was employed to estimate and test genetic effects of QTLs and QTL × sex interaction effects. The effectiveness of the model and statistical method was validated by a series of simulations. The results indicate that when markers are distributed sparsely on chromosomes, our method will substantially improve estimation accuracy as compared to the normal chiasmate F2 model. We also found that a sample size of hundreds was sufficiently large to unbiasedly estimate all the four types of epistases (i.e., additive-additive, additive-dominance, dominance-additive, and dominance-dominance) when the paired QTLs reside on different chromosomes in silkworm. Conclusion The proposed method could accurately estimate not only the additive, dominance and digenic epistatic effects but also their interaction effects with sex, correcting the potential bias and precision loss in the current QTL mapping practice of silkworm and thus representing an important addition to the arsenal of QTL mapping tools.

2011-01-01

64

Dynamic contrast-enhanced CT in suspected lung cancer: quantitative results.  

PubMed

Objectives: To examine whether dynamic contrast-enhanced CT (DCE-CT) could be used to characterise and safely distinguish between malignant and benign lung tumours in patients with suspected lung cancer. Methods: Using a quantitative approach to DCE-CT, two separate sets of regions of interest (ROIs) in tissues were placed in each tumour: large ROIs over the entire tumour and small ROIs over the maximally perfused parts of the tumour. Using mathematical modelling techniques and dedicated perfusion software, this yielded a plethora of results. Results: First, because of their non-normal distribution, DCE-CT measurements must be analysed using log scale data transformation. Second, there were highly significant differences between large ROI and small ROI measurements (p<0.001). Thus, the ROI method used in a given study should always be specified in advance. Third, neither quantitative parameters (blood flow and blood volume) nor semi-quantitative parameters (peak enhancement) could be used to distinguish between malignant and benign tumours. This was irrespective of the method of quantification used for large ROIs (0.13quantitative approach to DCE-CT is not a clinically usable method for characterising lung tumours. PMID:24029629

Harders, S W; Madsen, H H; Nellemann, H M; Rasmussen, T R; Thygesen, J; Hager, H; Andersen, N T; Rasmussen, F

2013-09-12

65

Spy quantitative inspection with a machine vision light sectioning method  

NASA Astrophysics Data System (ADS)

Machine vision light sectioning sensing is developed and expanded to the range of spy quantitative inspection for hole-like work pieces in this paper. A light beam from a semiconductor laser diode is converged into a line-shape by a cylindrical lens. A special compact reflecting-refracting prism group is designed to ensure that such a sectioning light is projected axially onto the inner surface, and to make the deformed line be imaged onto a CCD sensitive area. The image is digitized and captured into a computer by a 512×512 pixel card, and machine vision image processing methods such as thresholding, line centre detect and the least-squares method are developed for contour feature extraction and description. Two other important problems in such an inspection system are how to orientate the deep-going optical probe and how to bring the projected line into focus. A focusing criterion based on image position deviation and a four-step orientating procedure are put forward, and analysed to be feasible respectively. The experimental results show that the principle is correct and the techniques are realizable, and a good future for application in industry is possible.

Tu, Da-Wei; Lin, Cai-Xing

2000-08-01

66

Lenticules for the control of quantitative methods in food microbiology.  

PubMed

Control dried organisms as lenticules are a dependable and convenient alternative to wet cultures for quality assurance and process controls in routine food microbiology. Lenticules are designed to give a fixed, reproducible inoculum over an extended period of time without loss of cultural characteristics or viability. During a period of 23 months, 596 paired counts were performed by both Miles and Misra and spiral plating techniques on lenticule controls. Correlation between the two methods and within batches was excellent. Only 14 counts (2.5%) fell outside the standard operating limit of 0.5 log10. All were within 1.0 log10. On two separate occasions, replicate runs were performed on five reconstituted lenticules from a batch. The counts obtained showed variation within and between lenticules only slightly in excess of what is expected by chance. Lenticule replicates performed by three other laboratories also produced satisfactory results. It is thought that lenticules could improve the accuracy of total plate counts and lead to a better standardization of quantitative methods in food microbiology within and between laboratories. PMID:9830128

Codd, A A; Richardson, I R; Andrews, N

1998-11-01

67

Analysis of 129I in Groundwater Samples: Direct and Quantitative Results below the Drinking Water Standard  

SciTech Connect

Due to its long half-life (15.7 million years) and relatively unencumbered migration in subsurface environments, 129I has been recognized as a contaminant of concern at numerous federal, private, and international facilities. In order to understand the long-term risk associated with 129I at these locations, quantitative analysis of groundwater samples must be performed. However, the ability to quantitatively assess the 129I content in groundwater samples requires specialized extraction and sophisticated analytical techniques, which are complicated and not always available to the general scientific community. This paper highlights an analytical method capable of directly quantifying 129I in groundwater samples at concentrations below the MCL without the need for sample pre-concentration. Samples were analyzed on a Perkin Elmer ELAN DRC II ICP-MS after minimal dilution using O2 as the reaction gas. Analysis of continuing calibration verification standards indicated that the DRC mode could be used for quantitative analysis of 129I in samples below the drinking water standard (0.0057 ng/ml or 1 pCi/L). The low analytical detection limit of 129I analysis in the DRC mode coupled with minimal sample dilution (1.02x) resulted in a final sample limit of quantification of 0.0051 ng/ml. Subsequent analysis of three groundwater samples containing 129I resulted in fully quantitative results in the DRC mode, and spike recovery analyses performed on all three samples confirmed that the groundwater matrix did not adversely impact the analysis of 129I in the DRC mode. This analytical approach has been proven to be a cost-effective, high-throughput technique for the direct, quantitative analysis of 129I in groundwater samples at concentrations below the current MCL.

Brown, Christopher F.; Geiszler, Keith N.; Lindberg, Michael J.

2007-03-03

68

A Quantitative Method to Analyze Drosophila Pupal Eye Patterning  

Microsoft Academic Search

BackgroundThe Drosophila pupal eye has become a popular paradigm for understanding morphogenesis and tissue patterning. Correct rearrangement of cells between ommatidia is required to organize the ommatidial array across the eye field. This requires cell movement, cell death, changes to cell-cell adhesion, signaling and fate specification.MethodologyWe describe a method to quantitatively assess mis-patterning of the Drosophila pupal eye and objectively

Ruth I. Johnson; Ross L. Cagan; Thomas A. Reh

2009-01-01

69

Quantitative analysis of human immunoregulatory cytokines by electrochemiluminescence method  

Microsoft Academic Search

Quantitative analysis of human immunoregulatory cytokines in physiological media and cell cultures plays an important role in fundamental and clinical research. Here we describe the quantification of interleukin (IL)-2, IL-4, IL-10 and interferon-? (IFN-?) in human serum and peripheral blood mononuclear cell (PBMC)-conditioned medium by electrochemiluminescence method (ECL). We demonstrate that this approach allows to detect cytokine concentration from 1

Sergey V. Sennikov; Sergey V. Krysov; Tatiana V. Injelevskaya; Alexandr N. Silkov; Lyubov V. Grishina; Vladimir A. Kozlov

2003-01-01

70

Comparison of multivariate calibration methods for quantitative spectral analysis  

SciTech Connect

The quantitative prediction abilities of four multivariate calibration methods for spectral analyses are compared by using extensive Monte Carlo simulations. The calibration methods compared include inverse least-squares (ILS), classical least-squares (CLS), partial least-squares (PLS), and principal component regression (PCR) methods. ILS is a frequency-limited method while the latter three are capable of full-spectrum calibration. The simulations were performed assuming Beer's law holds and that spectral measurement errors and concentration errors associated with the reference method are normally distributed. Eight different factors that could affect the relative performance of the calibration methods were varied in a two-level, eight-factor experimental design in order to evaluate their effect on the prediction abilities of the four methods. It is found that each of the three full-spectrum methods has its range of superior performance. The frequency-limited ILS method was never the best method, although in the presence of relatively large concentration errors it sometimes yields comparable analysis precision to the full-spectrum methods for the major spectral component. The importance of each factor in the absolute and relative performances of the four methods is compared.

Thomas, E.V.; Haaland, D.M. (Sandia National Laboratories, Albuquerque, NM (USA))

1990-05-15

71

Quantitative Analysis of Uranium, Thorium and Potassium from Lignite Ash by Neutron Activation Method  

Microsoft Academic Search

Quantitative analysis of uranium, thorium and potassium from lignite ash is determined by Neutron Activation (NA) Method, using the samples of fly ash and bottom ash from Krabi and Mae Moh power plants. The analysis has been performed since 1981. The result obtained by this method during 1981 and 1983 shows that the quantities of U, Th and K in

Nongluck Savanonda; Ekachai Prongpunyasakul; Supapol Ratanakorn

1986-01-01

72

Noise Effects In Various Quantitative Susceptibility Mapping Methods.  

PubMed

Various regularization methods have been proposed for single-orientation quantitative susceptibility mapping (QSM), which is an ill-posed magnetic field to susceptibility source inverse problem. Noise amplification, a major issue in inverse problems, manifests as streaking artifacts and quantification errors in QSM and has not been comparatively evaluated in these algorithms. In this paper, various QSM methods were systematically categorized for noise analysis. Six representative QSM methods were selected from four categories: two non-Bayesian methods with alteration or approximation of the dipole kernel to overcome the ill conditioning; four Bayesian methods using a general mathematical prior or a specific physical structure prior to select a unique solution, and using a data fidelity term with or without noise weighting. The effects of noise in these QSM methods were evaluated by reconstruction errors in simulation and image quality in 50 consecutive human subjects. Bayesian QSM methods with noise weighting consistently reduced root mean squared errors in numerical simulations and increased image quality scores in the human brain images, when compared to non-Bayesian methods and to corresponding Bayesian methods without noise weighting (p 0.001). In summary, noise effects in QSM can be reduced using Bayesian methods with proper noise weighting. PMID:23751950

Wang, Shuai; Liu, Tian; Chen, Weiwei; Spincemaille, Pascal; Wisnieff, Cynthia; Tsiouris, A John; Zhu, Wenzhen; Pan, Chu; Zhao, Lingyun; Wang, Yi

2013-06-07

73

Mapcurves: A Quantitative Method for Comparing Categorical Maps  

SciTech Connect

We present Mapcurves, a quantitative goodness-of-fit (GOF) method that unambiguously shows the degree of spatial concordance between two or more categorical maps. Mapcurves graphically and quantitatively evaluate the degree of fit among any number of maps and quantify a GOF for each polygon, as well as the entire map. The Mapcurve method indicates a perfect fit even if all polygons in one map are comprised of unique sets of the polygons in another map, if the coincidence among map categories is absolute. It is not necessary to interpret (or even know) legend descriptors for the categories in the maps to be compared, since the degree of fit in the spatial overlay alone forms the basis for the comparison. This feature makes Mapcurves ideal for comparing maps derived from remotely sensed images. A translation table is provided for the categories in each map as an output. Since the comparison is category-based rather than cell-based, the GOF is resolution-independent. Mapcurves can be applied either to entire map categories or to individual raster patches or vector polygons. Mapcurves also have applications for quantifying the spatial uncertainty of particular map features.

Hargrove, William Walter [ORNL; Hoffman, Forrest M [ORNL; Hessburg, Paul [U.S.D.A. Forest Service

2006-01-01

74

Comparison of the Multiple-Sample Means with Composite Sample Results for Fecal Indicator Bacteria by Quantitative PCR and Culture  

PubMed Central

Few studies have addressed the efficacy of composite sampling for measuring indicator bacteria by quantitative PCR (qPCR). We compared results from composited samples with multiple-sample means for culture- and qPCR-based water quality monitoring. Results from composited samples for both methods were similarly correlated to multiple-sample means and predicted criteria exceedances equally.

Wymer, Larry J.; Dufour, Alfred P.; Wade, Timothy J.

2012-01-01

75

System and methods for wide-field quantitative fluorescence imaging during neurosurgery.  

PubMed

We report an accurate, precise and sensitive method and system for quantitative fluorescence image-guided neurosurgery. With a low-noise, high-dynamic-range CMOS array, we perform rapid (integration times as low as 50 ms per wavelength) hyperspectral fluorescence and diffuse reflectance detection and apply a correction algorithm to compensate for the distorting effects of tissue absorption and scattering. Using this approach, we generated quantitative wide-field images of fluorescence in tissue-simulating phantoms for the fluorophore PpIX, having concentrations and optical absorption and scattering variations over clinically relevant ranges. The imaging system was tested in a rodent model of glioma, detecting quantitative levels down to 20 ng/ml. The resulting performance is a significant advance on existing wide-field quantitative imaging techniques, and provides performance comparable to a point-spectroscopy probe that has previously demonstrated significant potential for improved detection of malignant brain tumors during surgical resection. PMID:23903142

Valdes, Pablo A; Jacobs, Valerie L; Wilson, Brian C; Leblond, Frederic; Roberts, David W; Paulsen, Keith D

2013-08-01

76

Quantitative methods in pharmacovigilance: focus on signal detection.  

PubMed

Pharmacovigilance serves to detect previously unrecognised adverse events associated with the use of medicines. The simplest method for detecting signals of such events is crude inspection of lists of spontaneously reported drug-event combinations. Quantitative and automated numerator-based methods such as Bayesian data mining can supplement or supplant these methods. The theoretical basis and limitations of these methods should be understood by drug safety professionals, and automated methods should not be automatically accepted. Published evaluations of these techniques are mainly limited to large regulatory databases, and performance characteristics may differ in smaller safety databases of drug developers. Head-to-head comparisons of the major techniques have not been published. Regardless of previous statistical training, pharmacovigilance practitioners should understand how these methods work. The mathematical basis of these techniques should not obscure the numerous confounders and biases inherent in the data. This article seeks to make automated signal detection methods transparent to drug safety professionals of various backgrounds. This is accomplished by first providing a brief overview of the evolution of signal detection followed by a series of sections devoted to the methods with the greatest utilisation and evidentiary support: proportional reporting rations, the Bayesian Confidence Propagation Neural Network and empirical Bayes screening. Sophisticated yet intuitive explanations are provided for each method, supported by figures in which the underlying statistical concepts are explored. Finally the strengths, limitations, pitfalls and outstanding unresolved issues are discussed. Pharmacovigilance specialists should not be intimidated by the mathematics. Understanding the theoretical basis of these methods should enhance the effective assessment and possible implementation of these techniques by drug safety professionals. PMID:12580646

Hauben, Manfred; Zhou, Xiaofeng

2003-01-01

77

A phantom study of the quantitative behavior of Bayesian PET reconstruction methods  

Microsoft Academic Search

The authors examine the behavior of a Bayesian protocol for reconstruction of PET images in terms of the quantitative accuracy of the resulting Region-of-Interest (ROI) statistics. The authors' protocol uses a rapidly converging algorithm to compute a MAP estimate of the 3D PET image and includes novel methods for accurate attenuation and scatter modeling. The image is modeled using a

Erkan U. Mumcuoglu; R. M. Leahy; Z. Zhou; S. R. Cherry

1995-01-01

78

Rapid quantitative method for total brominated vegetable oil in soft drinks using ion chromatography  

Microsoft Academic Search

A simple, quantitative and rapid method for total brominated vegetable oil (BVO) using ion chromatography (IC) with suppressed conductivity detection was developed and successfully applied to soft drinks with results expressed as inorganic bromide anion. The procedure involves extraction of BVO with diethyl ether and treatment with zinc dust in a solution of acetic acid, giving recoveries ranging between 92.5

Ashraf A. Yousef; Alaa B. Abbas; Bassam Sh. Badawi; Wafaa Y. Al-Jowhar; Esam A. Zain; Seham A. El-Mufti

2012-01-01

79

Nuclear medicine and imaging research (instrumentation and quantitative methods of evaluation)  

SciTech Connect

This document is the annual progress report for project entitled 'Instrumentation and Quantitative Methods of Evaluation.' Progress is reported in separate sections individually abstracted and indexed for the database. Subject areas reported include theoretical studies of imaging systems and methods, hardware developments, quantitative methods of evaluation, and knowledge transfer: education in quantitative nuclear medicine imaging.

Beck, R.N.; Cooper, M.; Chen, C.T.

1992-07-01

80

A quantitative evaluation of various deconvolution methods and their applications in the deconvolution of plasma spectra  

NASA Astrophysics Data System (ADS)

A quantitative evaluation of various deconvolution methods and their applications in processing plasma emitted spectra was performed. The iterative deconvolution algorithms evaluated here include Jansson's method, Richardson-Lucy's method, the maximum a posteriori method and Gold's method. The evaluation criteria include minimization of the sum of squared errors and the sum of squared relative error of parameters, and their rate of convergence. After comparing deconvolved results using these methods, it was concluded that Jansson's and Gold's methods were able to provide good profiles that are visually close to the original spectra. Additionally, Gold's method generally gives the best results when considering all the criteria above. The applications to the actual plasma spectra obtained from the EAST tokamak with these methods are also presented in this paper. The deconvolution results with Gold's and Jansson's methods show that the effects of instruments can be satisfactorily eliminated and clear spectra are recovered.

Xiong, Yanwei; Shi, Yuejiang; Li, Yingying; Fu, Jia; Lu, Bo; Zhang, Hongming; Wang, Xiaoguang; Wang, Fudi; Shen, Yongcai

2013-06-01

81

Rapid quantitative pharmacodynamic imaging by a novel method: theory, simulation testing and proof of principle  

PubMed Central

Pharmacological challenge imaging has mapped, but rarely quantified, the sensitivity of a biological system to a given drug. We describe a novel method called rapid quantitative pharmacodynamic imaging. This method combines pharmacokinetic-pharmacodynamic modeling, repeated small doses of a challenge drug over a short time scale, and functional imaging to rapidly provide quantitative estimates of drug sensitivity including EC50 (the concentration of drug that produces half the maximum possible effect). We first test the method with simulated data, assuming a typical sigmoidal dose-response curve and assuming imperfect imaging that includes artifactual baseline signal drift and random error. With these few assumptions, rapid quantitative pharmacodynamic imaging reliably estimates EC50 from the simulated data, except when noise overwhelms the drug effect or when the effect occurs only at high doses. In preliminary fMRI studies of primate brain using a dopamine agonist, the observed noise level is modest compared with observed drug effects, and a quantitative EC50 can be obtained from some regional time-signal curves. Taken together, these results suggest that research and clinical applications for rapid quantitative pharmacodynamic imaging are realistic.

Koller, Jonathan M.; Miller, Brad D.

2013-01-01

82

Quantitative analysis results of CE-1 X-ray fluorescence spectrometer ground base experiment  

NASA Astrophysics Data System (ADS)

As the nearest celestial body to the earth, the moon has become a hot spot again in astronomy field recently. The element analysis is a much important subject in many lunar projects. Remote X-ray spectrometry plays an important role in the geochemical exploration of the solar bodies. Because of the quasi-vacuum atmosphere on the moon, which has no absorption of X-ray, the X-ray fluorescence analysis is an effective way to determine the elemental abundance of lunar surface. The CE-1 X-ray fluorescence spectrometer (CE-1/XFS) aims to map the major elemental compositions on the lunar surface. This paper describes a method for quantitative analysis of elemental compositions. A series of ground base experiments are done to examine the capability of XFS. The obtained results, which show a reasonable agreement with the certified values at a 30% uncertainty level for major elements, are presented.

Cui, Xing-Zhu; Wang, Huan-Yu; Zhang, Cheng-Mo; Chen, Yong; Zhang, Jia-Yu; Peng, Wen-Xi; Cao, Xue-Lei; Liang, Xiao-Hua; Wang, Jin-Zhou; Gao, Min; Yang, Jia-Wei

2008-01-01

83

Bridging the gap between qualitative and quantitative colocalization results in fluorescence microscopy studies  

PubMed Central

Quantitative colocalization studies suffer from the lack of unified approach to interpret obtained results. We developed a tool to characterize the results of colocalization experiments in a way so that they are understandable and comparable both qualitatively and quantitatively. Employing a fuzzy system model and computer simulation, we produced a set of just five linguistic variables tied to the values of popular colocalization coefficients: “Very Weak”, “Weak”, “Moderate”, “Strong”, and “Very Strong”. The use of the variables ensures that the results of colocalization studies are properly reported, easily shared, and universally understood by all researchers working in the field. When new coefficients are introduced, their values can be readily fitted into the set.

Zinchuk, Vadim; Wu, Yong; Grossenbacher-Zinchuk, Olga

2013-01-01

84

Quantitative evaluation of mammographic densities: a comparison of methods of assessment.  

PubMed

Differences in the proportion of the breast occupied by mammographic densities have been shown to be associated with differences in breast cancer risk. However, estimation of these densities by radiologists may be subject to error, and it is likely that quantitative measurement will reduce misclassification of densities and strengthen their association with risk of breast cancer. The objective of this study was to compare the extent of mammographic densities estimated subjectively by an experienced radiologist with the measured extent of densities using a digital planimeter. A total of 225 sets of mammograms from women aged 40-49 years and enrolled in the Canadian National Breast Screening Study (NBSS) were selected. The extent of the radiological densities was estimated visually by one radiologist. Independently, the total area of the breast and the areas of density were traced and measured using a digital planimeter. Visual estimations and measurements of mammographic densities were then compared to determine the extent of agreement between the two methods. In general, the two methods showed good agreement (kappa = 0.78). The measured area of mammographic densities tended to be slightly greater than the radiologist's estimations. Both methods were highly reproducible (radiologist-dependent method, kappa = 0.89; quantitative method, r = 0.95, P = 0.0001). Our results indicate that measurement of the area of mammographic density using a quantitative method is reliable, and correlates well with assessment by an experienced radiologist. The method may be useful for identifying women at increased risk of breast cancer. PMID:7549820

Lee-Han, H; Cooke, G; Boyd, N F

1995-08-01

85

Business Scenario Evaluation Method Using Monte Carlo Simulation on Qualitative and Quantitative Hybrid Model  

NASA Astrophysics Data System (ADS)

We propose a business scenario evaluation method using qualitative and quantitative hybrid model. In order to evaluate business factors with qualitative causal relations, we introduce statistical values based on propagation and combination of effects of business factors by Monte Carlo simulation. In propagating an effect, we divide a range of each factor by landmarks and decide an effect to a destination node based on the divided ranges. In combining effects, we decide an effect of each arc using contribution degree and sum all effects. Through applied results to practical models, it is confirmed that there are no differences between results obtained by quantitative relations and results obtained by the proposed method at the risk rate of 5%.

Samejima, Masaki; Akiyoshi, Masanori; Mitsukuni, Koshichiro; Komoda, Norihisa

86

The distinction between qualitative and quantitative research methods is problematic  

Microsoft Academic Search

The distinction between qualitative and quantitative research is abstract, very general and its value is usually taken for\\u000a granted. In contrast, this article attempts to show that the distinction between qualitative and quantitative research is\\u000a unclear, poor and therefore of limited value and that its popularity risks leading to unfortunate consequences. Various arguments\\u000a are presented for this conclusion. For example,

Carl Martin Allwood

2012-01-01

87

Quantitative integration of single-subject studies: Methods and misinterpretations  

PubMed Central

Derenne and Baron (1999) criticized a quantitative literature review by Kollins, Newland, and Critchfield (1997) and raised several important issues with respect to the integration of single-subject data. In their criticism they argued that the quantitative integration of data across experiments conducted by Kollins et al. is a meta-analysis and, as such, is inappropriate. We reply that Kollins et al. offered behavior analysts a technique for integrating quantitative information in a way that draws from the strengths of behavior analysis. Although the quantitative technique is true to the original spirit of meta-analysis, it bears little resemblance to meta-analyses as currently conducted or defined and offers behavior analysts a potentially useful tool for comparing data from multiple sources. We also argue that other criticisms raised by Derenne and Baron were inaccurate or irrelevant to the original article. Our response highlights two main points: (a) There are meaningful quantitative techniques for examining single-subject data across studies without compromising the integrity of behavior analysis; and (b) the healthiest way to refute or question findings in any viable field of scientific inquiry is through empirical investigation.

Kollins, Scott H.; Newland, M. Christopher; Critchfield, Thomas S.

1999-01-01

88

A calibration-free, one-step method for quantitative photoacoustic tomography  

PubMed Central

Purpose: Recently reported quantitative photoacoustic tomography (PAT) has significantly expanded the utilities of PAT because it allows for recovery of tissue optical absorption coefficient which directly correlates with tissue physiological information. However, the recovery of optical absorption coefficient by the existing quantitative PAT approaches strongly depends on the accuracy of absorbed energy density distribution, and on the knowledge of accurate strength and distribution of incident light source. The purpose of this study is to develop a new algorithm for the reconstruction of optical absorption coefficient that does not depend on these initial parameters. Methods: Here the authors propose a novel one-step reconstruction approach that can directly recover optical absorption coefficient from photoacoustic measurements along boundary domain. The authors validate the method using simulation and phantom experiments. Results: The authors have demonstrated experimental evidence that it is possible to directly recover optical absorption coefficient maps using boundary photoacoustic measurements coupled with the photon diffusion equation in just one step. The authors found that the method described is able to quantitatively reconstruct absorbing objects with different sizes and optical contrast levels. Conclusions: Compared to the authors’ previous two-step methods, the reconstruction results obtained here show that the one-step scheme can significantly improve the accuracy of absorption coefficient recovery.

Yuan, Zhen; Jiang, Huabei

2012-01-01

89

Testing alleged mediumship: methods and results.  

PubMed

Mediums claim to be able to communicate with the deceased. Such claims attract a considerable amount of public interest and, if valid, have important implications for many areas of psychology. For over 100 years, researchers have tested alleged mediums. This work has obtained mixed results and provoked a considerable amount of methodological debate. This paper reviews the key issues in this debate, describes how the authors devised a method of testing that aimed to prevent the many problems that have hindered past research, and how they then used this method to test several professional mediums. The results of this work did not support the existence of genuine mediumistic ability. Competing interpretations of these results are discussed, along with ways in which the methodology presented in the paper could be used to assess conceptually similar, but non-paranormal, claims made in clinical, occupational and forensic contexts. PMID:15969829

O'keeffe, Ciarán; Wiseman, Richard

2005-05-01

90

A quantitative method for evaluating the performances of hyperspectral image fusion  

Microsoft Academic Search

Hyperspectral image fusion is a key technique of hyperspectral data processing. In recent years, many fusion methods have been proposed, but there is little work concerning evaluation of the performances of different image fusion methods. In this paper, a method called quantitative correlation analysis {(QCA)} is proposed, which provides a quantitative measure of the information transferred by an image fusion

Qiang Wang; Yi Shen; Ye Zhang; Jian Qiu Zhang

2003-01-01

91

Revisiting the Quantitative-Qualitative Debate: Implications for Mixed-Methods Research  

Microsoft Academic Search

Health care research includes many studies that combine quantitative and qualitative methods. In this paper, we revisit the quantitative-qualitative debate and review the arguments for and against using mixed-methods. In addition, we discuss the implications stemming from our view, that the paradigms upon which the methods are based have a different view of reality and therefore a different view of

JOANNA E. M. SALE; LYNNE H. LOHFELD; Kevin Brazil

2002-01-01

92

Good results with the Ponseti method  

PubMed Central

Background and purpose In 2002–2003, several hospitals in Norway introduced the Ponseti method for treating clubfoot. The present multicenter study was conducted to evaluate the initial results of this method, and to compare them to the good results reported in the literature. Patients and methods 116 children with 162 congenital idiopathic clubfeet who were born between 2004 and 2006 were treated with the Ponseti method at 8 hospitals in Norway. All children were prospectively registered at birth, and 116 feet were assessed according to Pirani before treatment was started. 63% used a standard bilateral foot abduction brace, and 32% used a unilateral above-the-knee brace. One of the authors examined all feet at a mean age of 4 years. At follow-up, all feet were assessed by Pirani’s scoring system, and range of motion of the foot and ankle was measured. Results At follow-up, 77% of the feet had a Pirani score of 0.5 or better, good dorsiflexion and external rotation, and no forefoot adduction. An Achilles tenotomy had been performed in 79% of the feet. Compliance to any brace was good; only 7% were defined as non-compliant. Extensive soft tissue release had been performed in 3% of the feet. We found no statistically significant differences between the two braces, except a tendency of better Pirani score in the group using the bilateral foot abduction brace, and a tendency of better compliance in patients using the unilateral brace. Better Pirani scores were found in children who were treated at the largest hospitals. Interpretation After introducing the Ponseti method in Norway, the clinical outcome was good and in accordance with the reports from single centers. Only 5 feet needed extensive surgery during the first 4 years of life.

2012-01-01

93

Understanding Youth: Using Qualitative Methods to Verify Quantitative Community Indicators  

Microsoft Academic Search

Community- and individual-level data were collected from interviews with 1,294 boys and girls, 13 to 19 years old, in three impoverished urban communities of Beirut. Univariate analyses of variables provide quantitative indicators of adolescents' lives and communities. Researchers including the authors, interested in using these indicators to plan for community interventions with youth in the Palestinian refugee camp, discuss the

Jihad Makhoul; Rima Nakkash

2009-01-01

94

Issues Related to Data Analysis and Quantitative Methods in PER  

NSDL National Science Digital Library

This paper, presented at the 2002 Physics Education Research Conference, offers authors' discussion of some issues that always arise, implicitly or explicitly, when conducting quantitative research and carrying out data analysis in Physics Education Research. (Most are relevant for qualitative research as well.)

Meltzer, David E.

2006-12-06

95

Issues Related to Data Analysis and Quantitative Methods in PER  

NSDL National Science Digital Library

This paper, presented at the 2002 Physics Education Research Conference, offers authors' discussion of some issues that always arise, implicitly or explicitly, when conducting quantitative research and carrying out data analysis in Physics Education Research. (Most are relevant for qualitative research as well.)

Meltzer, David (David Elliott)

2010-07-22

96

Methods of scattering corrections for quantitative neutron radiography  

Microsoft Academic Search

From neutron radiography experiments, often statements like “how many grams of water are in my sample?” are expected. Such statements are delicate, because contributions of scattered neutrons in the image signal disturb the radiographies for a simple quantitative evaluation.The idea is to consider the scattered neutrons in a computational procedure. The obtained corrected image data set can then be evaluated

René Hassanein; Eberhard Lehmann; Peter Vontobel

2005-01-01

97

Quantitative Methods for Administrative Decision Making in Junior Colleges.  

ERIC Educational Resources Information Center

|With the rapid increase in number and size of junior colleges, administrators must take advantage of the decision-making tools already used in business and industry. This study investigated how these quantitative techniques could be applied to junior college problems. A survey of 195 California junior college administrators found that the…

Gold, Benjamin Knox

98

A new quantitative method for gunshot residue analysis by ion beam analysis.  

PubMed

Imaging and analyzing gunshot residue (GSR) particles using the scanning electron microscope equipped with an energy dispersive X-ray spectrometer (SEM-EDS) is a standard technique that can provide important forensic evidence, but the discrimination power of this technique is limited due to low sensitivity to trace elements and difficulties in obtaining quantitative results from small particles. A new, faster method using a scanning proton microbeam and Particle Induced X-ray Emission (?-PIXE), together with Elastic Backscattering Spectrometry (EBS) is presented for the non-destructive, quantitative analysis of the elemental composition of single GSR particles. In this study, the GSR particles were all Pb, Ba, Sb. The precision of the method is assessed. The grouping behaviour of different makes of ammunition is determined using multivariate analysis. The protocol correctly groups the cartridges studied here, with a confidence >99%, irrespective of the firearm or population of particles selected. PMID:23775063

Christopher, Matthew E; Warmenhoeven, John-William; Romolo, Francesco S; Donghi, Matteo; Webb, Roger P; Jeynes, Christopher; Ward, Neil I; Kirkby, Karen J; Bailey, Melanie J

2013-06-18

99

Quantitative Measurement Method for Possible Rib Fractures in Chest Radiographs  

PubMed Central

Objectives This paper proposes a measurement method to quantify the abnormal characteristics of the broken parts of ribs using local texture and shape features in chest radiographs. Methods Our measurement method comprises two steps: a measurement area assignment and sampling step using a spline curve and sampling lines orthogonal to the spline curve, and a fracture-ness measurement step with three measures, asymmetry and gray-level co-occurrence matrix based measures (contrast and homogeneity). They were designed to quantify the regional shape and texture features of ribs along the centerline. The discriminating ability of our method was evaluated through region of interest (ROI) analysis and rib fracture classification test using support vector machine. Results The statistically significant difference was found between the measured values from fracture and normal ROIs; asymmetry (p < 0.0001), contrast (p < 0.001), and homogeneity (p = 0.022). The rib fracture classifier, trained with the measured values in ROI analysis, detected every rib fracture from chest radiographs used for ROI analysis, but it also classified some unbroken parts of ribs as abnormal parts (8 to 17 line sets; length of each line set, 2.998 ± 2.652 mm; length of centerlines, 131.067 ± 29.460 mm). Conclusions Our measurement method, which includes a flexible measurement technique for the curved shape of ribs and the proposed shape and texture measures, could discriminate the suspicious regions of ribs for possible rib fractures in chest radiographs.

Kim, Jaeil; Kim, Sungjun; Kim, Young Jae

2013-01-01

100

Sequencing human ribs into anatomical order by quantitative multivariate methods.  

PubMed

Little research has focussed on methods to anatomically sequence ribs. Correct anatomical sequencing of ribs assists in determining the location and distribution of regional trauma, age estimation, number of puncture wounds, number of individuals, and personal identification. The aim of the current study is to develop a method for placing fragmented and incomplete rib sets into correct anatomical position. Ribs 2-10 were used from eleven cadavers of an Australian population. Seven variables were measured from anatomical locations on the rib. General descriptive statistics were calculated for each variable along with an analysis of variance (ANOVA) and ANOVA with Bonferroni statistics. Considerable overlap was observed between ribs for univariate methods. Bivariate and multivariate methods were then applied. Results of the ANOVA with post hoc Bonferroni statistics show that ratios of various dimensions of a single rib could be used to sequence it within adjacent ribs. Using multiple regression formulae, the most accurate estimation of the anatomical rib number occurs when the entire rib is found in isolation. This however, is not always possible. Even when only the head and neck of the rib are preserved, a modified multivariate regression formula assigned 91.95% of ribs into correct anatomical position or as an adjacent rib. Using multivariate methods it is possible to sequence a single human rib with a high level of accuracy and they are superior to univariate methods. Left and right ribs were found to be highly symmetrical. Some rib dimensions were greater in males than in females, but overall the level of sexual dimorphism was low. PMID:22560535

Cirillo, John; Henneberg, Maciej

2012-05-03

101

Quantitative sacroiliac scintigraphy. The effect of method of selection of region of interest  

SciTech Connect

Various authors have advocated quantitative methods of evaluating bone scintigrams to detect sacroiliitis, while others have not found them useful. Many explanations for this disagreement have been offered, including differences in the method of case selection, ethnicity, gender, and previous drug therapy. It would appear that one of the most important impediments to consistent results is the variability of selecting sacroiliac joint and reference regions of interest (ROIs). The effect of ROI selection would seem particularly important because of the normal variability of radioactivity within the reference regions that have been used (sacrum, spine, iliac wing) and the inhomogeneity of activity in the SI joints. We have investigated the effect of ROI selection, using five different methods representative of, though not necessarily identical to, those found in the literature. Each method produced unique mean indices that were different for patients with ankylosing spondylitis (AS) and controls. The method of Ayres (19) proved superior (largest mean difference, smallest variance), but none worked well as a diagnostic tool because of substantial overlap of the distributions of indices of patient and control groups. We conclude that ROI selection is important in determining results, and quantitative scintigraphic methods in general are not effective tools for diagnosing AS. Among the possible factors limiting success, difficulty in selecting a stable reference area seems of particular importance.

Davis, M.C.; Turner, D.A.; Charters, J.R.; Golden, H.E.; Ali, A.; Fordham, E.W.

1984-06-01

102

A new method for quantitating total lesion glucose metabolic changes in serial tumor FDG PET studies  

SciTech Connect

Accurate quantitative FDG PET studies have the potential for important applications in clinical oncology for monitoring therapy induced changes in tumor glycolytic rates. Due to a number of technical problems that complicate the use of quantitative PET tumor imaging, methods which can maximize the accuracy and precision of such measurements are advantageous. In this study, we developed and evaluated a method for reducing the errors caused by the conventional single plane, single ROI analysis in parametric images generated from pixel by pixel Patlak graphic analysis (PGA) in FDG PET studies of melanoma patients. We compared this new method to the conventional ROI method. The new processing method involves (1) generating the correlation coefficient (r) constrained Patlak parametric images from dynamic PET data; (2) summing up all the planes which cover the lesion; (3) defining a single ROI which covers the whole lesion in the summing image and determining the total lesion glucose metabolic index (K{sub T}, ml/min/lesion). Although only a single ROI was defined on the summing image, the glucose metabolic index obtained showed negligible difference (<1%) compared to those obtained from multiple ROIs on multiple planes of unconstrained parametric images. When the dynamic PET images were rotated and translated to simulate different patient positionings between scans at different times, the results obtained from the new method showed negligible difference (<2%). In summary, we present a simple but reliable method to quantitatively monitor the total lesion glucose metabolic changes during tumor growth. The method has several advantages over the conventional single ROI, single plane evaluation: (1) less sensitive to the ROI definition; (2) smaller intra- and inter-observer variations and (3) not requiring image registrations of serial scan data.

Wu, H.M.; Hoh, C.K.; Huang, S.C.; Phelps, M.E. [UCLA School of Medicine, Los Angeles, CA (United States)] [and others

1994-05-01

103

To develop a quantitative method for predicting shrinkage porosity in squeeze casting  

Microsoft Academic Search

In order to secure high strength and high elongation of suspension parts, it is critical to predict shrinkage porosity quantitatively. A new simulation method for quantitative prediction of shrinkage porosity when replenishing molten metal has been proposed for squeeze casting process. To examine the accuracy of the calculation model, the proposed method was applied to a plate model.

Kenichiro Mine; Shinji Sanakanishi; Koichi Anzai

104

Application of new least-squares methods for the quantitative infrared analysis of multicomponent samples  

SciTech Connect

Improvements have been made in previous least-squares regression analyses of infrared spectra for the quantitative estimation of concentrations of multicomponent mixtures. Spectral baselines are fitted by least-squares methods, and overlapping spectral features are accounted for in the fitting procedure. Selection of peaks above a threshold value reduces computation time and data storage requirements. Four weighted least-squares methods incorporating different baseline assumptions were investigated using FT-IR spectra of the three pure xylene isomers and their mixtures. By fitting only regions of the spectra that follow Beer's Law, accurate results can be obtained using three of the fitting methods even when baselines are not corrected to zero. Accurate results can also be obtained using one of the fits even in the presence of Beer's Law deviations. This is a consequence of pooling the weighted results for each spectral peak such that the greatest weighting is automatically given to those peaks that adhere to Beer's Law. It has been shown with the xylene spectra that semiquantitative results can be obtained even when all the major components are not known or when expected components are not present. This improvement over previous methods greatly expands the utility of quantitative least-squares analyses.

Haaland, D.M.; Easterling, R.G.

1982-11-01

105

A Quantitative Method for Estimating Probable Public Costs of Hurricanes.  

PubMed

/ A method is presented for estimating probable public costs resulting from damage caused by hurricanes, measured as local government expenditures approved for reimbursement under the Stafford Act Section 406 Public Assistance Program. The method employs a multivariate model developed through multiple regression analysis of an array of independent variables that measure meteorological, socioeconomic, and physical conditions related to the landfall of hurricanes within a local government jurisdiction. From the regression analysis we chose a log-log (base 10) model that explains 74% of the variance in the expenditure data using population and wind speed as predictors. We illustrate application of the method for a local jurisdiction-Lee County, Florida, USA. The results show that potential public costs range from $4.7 million for a category 1 hurricane with winds of 137 kilometers per hour (85 miles per hour) to $130 million for a category 5 hurricane with winds of 265 kilometers per hour (165 miles per hour). Based on these figures, we estimate expected annual public costs of $2.3 million. These cost estimates: (1) provide useful guidance for anticipating the magnitude of the federal, state, and local expenditures that would be required for the array of possible hurricanes that could affect that jurisdiction; (2) allow policy makers to assess the implications of alternative federal and state policies for providing public assistance to jurisdictions that experience hurricane damage; and (3) provide information needed to develop a contingency fund or other financial mechanism for assuring that the community has sufficient funds available to meet its obligations. KEY WORDS: Hurricane; Public costs; Local government; Disaster recovery; Disaster response; Florida; Stafford Act PMID:9950698

BOSWELL; DEYLE; SMITH; BAKER

1999-04-01

106

Co-regulatory expression quantitative trait loci mapping: method and application to endometrial cancer  

PubMed Central

Background Expression quantitative trait loci (eQTL) studies have helped identify the genetic determinants of gene expression. Understanding the potential interacting mechanisms underlying such findings, however, is challenging. Methods We describe a method to identify the trans-acting drivers of multiple gene co-expression, which reflects the action of regulatory molecules. This method-termed co-regulatory expression quantitative trait locus (creQTL) mapping-allows for evaluation of a more focused set of phenotypes within a clear biological context than conventional eQTL mapping. Results Applying this method to a study of endometrial cancer revealed regulatory mechanisms supported by the literature: a creQTL between a locus upstream of STARD13/DLC2 and a group of seven IFN?-induced genes. This suggests that the Rho-GTPase encoded by STARD13 regulates IFN?-induced genes and the DNA damage response. Conclusions Because of the importance of IFN? in cancer, our results suggest that creQTL may provide a finer picture of gene regulation and may reveal additional molecular targets for intervention. An open source R implementation of the method is available at http://sites.google.com/site/kenkompass/.

2011-01-01

107

Development and evaluation of an improved quantitative 90Y bremsstrahlung SPECT method  

PubMed Central

Purpose: Yttrium-90 (90Y) is one of the most commonly used radionuclides in targeted radionuclide therapy (TRT). Since it decays with essentially no gamma photon emissions, surrogate radionuclides (e.g., 111In) or imaging agents (e.g., 99mTc MAA) are typically used for treatment planning. It would, however, be useful to image 90Y directly in order to confirm that the distributions measured with these other radionuclides or agents are the same as for the 90Y labeled agents. As a result, there has been a great deal of interest in quantitative imaging of 90Y bremsstrahlung photons using single photon emission computed tomography (SPECT) imaging. The continuous and broad energy distribution of bremsstrahlung photons, however, imposes substantial challenges on accurate quantification of the activity distribution. The aim of this work was to develop and evaluate an improved quantitative 90Y bremsstrahlung SPECT reconstruction method appropriate for these imaging applications. Methods: Accurate modeling of image degrading factors such as object attenuation and scatter and the collimator-detector response is essential to obtain quantitatively accurate images. All of the image degrading factors are energy dependent. Thus, the authors separated the modeling of the bremsstrahlung photons into multiple categories and energy ranges. To improve the accuracy, the authors used a bremsstrahlung energy spectrum previously estimated from experimental measurements and incorporated a model of the distance between 90Y decay location and bremsstrahlung emission location into the SIMIND code used to generate the response functions and kernels used in the model. This improved Monte Carlo bremsstrahlung simulation was validated by comparison to experimentally measured projection data of a 90Y line source. The authors validated the accuracy of the forward projection model for photons in the various categories and energy ranges using the validated Monte Carlo (MC) simulation method. The forward projection model was incorporated into an iterative ordered subsets-expectation maximization (OS-EM) reconstruction code to allow for quantitative SPECT reconstruction. The resulting code was validated using both a physical phantom experiment with spherical objects in a warm background and a realistic anatomical phantom simulation. In the physical phantom study, the authors evaluated the method in terms of quantitative accuracy of activity estimates in the spheres; in the simulation study, the authors evaluated the accuracy and precision of activity estimates from various organs and compared them to results from a previously proposed method. Results: The authors demonstrated excellent agreement between the experimental measurement and Monte Carlo simulation. In the XCAT phantom simulation, the proposed method achieved much better accuracy in the modeling (error in photon counts was ?1.1?%) compared to a previously proposed method (errors were more than 20??%); the quantitative accuracy of activity estimates was excellent for all organs (errors were from ?1.6?% to 11.9?%) and comparable to previously published results for 131I using the same collimator. Conclusions: The proposed 90Y bremsstrahlung SPECT reconstruction method provided very accurate estimates of organ activities, with accuracies approaching those previously observed for 131I. The method may be useful in verifying organ doses for targeted radionuclide therapy using 90Y.

Rong, Xing; Du, Yong; Ljungberg, Michael; Rault, Erwann; Vandenberghe, Stefaan; Frey, Eric C.

2012-01-01

108

A simplified method for quantitative assessment of the relative health and safety risk of environmental management activities  

SciTech Connect

This report presents a simplified method to assess the health and safety risk of Environmental Management activities of the US Department of Energy (DOE). The method applies to all types of Environmental Management activities including waste management, environmental restoration, and decontamination and decommissioning. The method is particularly useful for planning or tradeoff studies involving multiple conceptual options because it combines rapid evaluation with a quantitative approach. The method is also potentially applicable to risk assessments of activities other than DOE Environmental Management activities if rapid quantitative results are desired.

Eide, S.A.; Smith, T.H.; Peatross, R.G.; Stepan, I.E.

1996-09-01

109

The improvement of quantitative filling method of liquid propellant in a strategic missile  

NASA Astrophysics Data System (ADS)

A quantitative method for fueling a liquid strategic missile is introduced in this paper. Problems existing in this method are discussed. The approach for improvement is discussed and the design scheme is presented.

Zhang, Yongjing

1992-10-01

110

Accelerated Method of Quantitative Determination of Potato Glycoalkaloids (Uskorennyi Metod Kolichestvennogo Opredeleniya Glikoalkaloidov Kartofelya).  

National Technical Information Service (NTIS)

On the basis of the interaction of solanidine with methyl orange, an accelerated method of quantitative determination of potato glycoalkaloids has been developed. By this method, the content of glycoalkaloids in leaves, flowers and potato sprouts has been...

E. A. Tukalo G. N. Tsarik

1974-01-01

111

Method for Quantitative Determination of Dibutylphosphoric Acid in Solutions of Tributyl Phosphate in Synthine.  

National Technical Information Service (NTIS)

A method is proposed for the quantitative determination of dibutylphosphoric acid (DBP) in industrial solutions containing synthine sulfonation products. The method involves the following steps: (1) specimen to be analyzed is first treated with barium chl...

A. E. Klygin N. S. Koliada S. N. Fedotov

1982-01-01

112

A new method for robust quantitative and qualitative analysis of real-time PCR.  

PubMed

An automated data analysis method for real-time PCR needs to exhibit robustness to the factors that routinely impact the measurement and analysis of real-time PCR data. Robust analysis is paramount to providing the same interpretation for results regardless of the skill of the operator performing or reviewing the work. We present a new method for analysis of real-time PCR data, the maxRatio method, which identifies a consistent point within or very near the exponential region of the PCR signal without requiring user intervention. Compared to other analytical techniques that generate only a cycle number, maxRatio generates several measurements of amplification including cycle numbers and relative measures of amplification efficiency and curve shape. By using these values, the maxRatio method can make highly reliable reactive/nonreactive determination along with quantitative evaluation. Application of the maxRatio method to the analysis of quantitative and qualitative real-time PCR assays is shown along with examples of method robustness to, and detection of, amplification response anomalies. PMID:18603594

Shain, Eric B; Clemens, John M

2008-07-04

113

An Augmented Classical Least Squares Method for Quantitative Raman Spectral Analysis against Component Information Loss  

PubMed Central

We propose an augmented classical least squares (ACLS) calibration method for quantitative Raman spectral analysis against component information loss. The Raman spectral signals with low analyte concentration correlations were selected and used as the substitutes for unknown quantitative component information during the CLS calibration procedure. The number of selected signals was determined by using the leave-one-out root-mean-square error of cross-validation (RMSECV) curve. An ACLS model was built based on the augmented concentration matrix and the reference spectral signal matrix. The proposed method was compared with partial least squares (PLS) and principal component regression (PCR) using one example: a data set recorded from an experiment of analyte concentration determination using Raman spectroscopy. A 2-fold cross-validation with Venetian blinds strategy was exploited to evaluate the predictive power of the proposed method. The one-way variance analysis (ANOVA) was used to access the predictive power difference between the proposed method and existing methods. Results indicated that the proposed method is effective at increasing the robust predictive power of traditional CLS model against component information loss and its predictive power is comparable to that of PLS or PCR.

Zhou, Yan; Cao, Hui

2013-01-01

114

A new method for robust quantitative and qualitative analysis of real-time PCR  

PubMed Central

An automated data analysis method for real-time PCR needs to exhibit robustness to the factors that routinely impact the measurement and analysis of real-time PCR data. Robust analysis is paramount to providing the same interpretation for results regardless of the skill of the operator performing or reviewing the work. We present a new method for analysis of real-time PCR data, the maxRatio method, which identifies a consistent point within or very near the exponential region of the PCR signal without requiring user intervention. Compared to other analytical techniques that generate only a cycle number, maxRatio generates several measurements of amplification including cycle numbers and relative measures of amplification efficiency and curve shape. By using these values, the maxRatio method can make highly reliable reactive/nonreactive determination along with quantitative evaluation. Application of the maxRatio method to the analysis of quantitative and qualitative real-time PCR assays is shown along with examples of method robustness to, and detection of, amplification response anomalies.

Shain, Eric B.; Clemens, John M.

2008-01-01

115

Quantitative estimation of poikilocytosis by the coherent optical method  

NASA Astrophysics Data System (ADS)

The investigation upon the necessity and the reliability required of the determination of the poikilocytosis in hematology has shown that existing techniques suffer from grave shortcomings. To determine a deviation of the erythrocytes' form from the normal (rounded) one in blood smears it is expedient to use an integrative estimate. The algorithm which is based on the correlation between erythrocyte morphological parameters with properties of the spatial-frequency spectrum of blood smear is suggested. During analytical and experimental research an integrative form parameter (IFP) which characterizes the increase of the relative concentration of cells with the changed form over 5% and the predominating type of poikilocytes was suggested. An algorithm of statistically reliable estimation of the IFP on the standard stained blood smears has been developed. To provide the quantitative characterization of the morphological features of cells a form vector has been proposed, and its validity for poikilocytes differentiation was shown.

Safonova, Larisa P.; Samorodov, Andrey V.; Spiridonov, Igor N.

2000-05-01

116

Methods and results in characterizing electronic stethoscopes  

Microsoft Academic Search

Two methods for characterizing the acoustical properties of electronic stethoscopes are reported. The first method measures the frequency response of the stethoscope using a fluid-filled rubber ball that is excited by a mechanical shaker driven by broadband noise. The acoustic impedance of this phantom is designed to be similar to that of human body tissue. The second method measures the

R. L. Watrous; D. M. Grove; D. L. Bowen

2002-01-01

117

Link-based quantitative methods to identify differentially coexpressed genes and gene Pairs  

PubMed Central

Background Differential coexpression analysis (DCEA) is increasingly used for investigating the global transcriptional mechanisms underlying phenotypic changes. Current DCEA methods mostly adopt a gene connectivity-based strategy to estimate differential coexpression, which is characterized by comparing the numbers of gene neighbors in different coexpression networks. Although it simplifies the calculation, this strategy mixes up the identities of different coexpression neighbors of a gene, and fails to differentiate significant differential coexpression changes from those trivial ones. Especially, the correlation-reversal is easily missed although it probably indicates remarkable biological significance. Results We developed two link-based quantitative methods, DCp and DCe, to identify differentially coexpressed genes and gene pairs (links). Bearing the uniqueness of exploiting the quantitative coexpression change of each gene pair in the coexpression networks, both methods proved to be superior to currently popular methods in simulation studies. Re-mining of a publicly available type 2 diabetes (T2D) expression dataset from the perspective of differential coexpression analysis led to additional discoveries than those from differential expression analysis. Conclusions This work pointed out the critical weakness of current popular DCEA methods, and proposed two link-based DCEA algorithms that will make contribution to the development of DCEA and help extend it to a broader spectrum.

2011-01-01

118

A probabilistic method for computing quantitative risk indexes from medical injuries compensation claims.  

PubMed

Background: The increasing demand of health care services and the complexity of health care delivery require Health Care Organizations (HCOs) to approach clinical risk management through proper methods and tools. An important aspect of risk management is to exploit the analysis of medical injuries compensation claims in order to reduce adverse events and, at the same time, to optimize the costs of health insurance policies. Objectives: This work provides a probabilistic method to estimate the risk level of a HCO by computing quantitative risk indexes from medical injury compensation claims. Methods: Our method is based on the estimate of a loss probability distribution from compensation claims data through parametric and non-parametric modeling and Monte Carlo simulations. The loss distribution can be estimated both on the whole dataset and, thanks to the application of a Bayesian hierarchical model, on stratified data. The approach allows to quantitatively assessing the risk structure of the HCO by analyzing the loss distribution and deriving its expected value and percentiles. Results: We applied the proposed method to 206 cases of injuries with compensation requests collected from 1999 to the first semester of 2007 by the HCO of Lodi, in the Northern part of Italy. We computed the risk indexes taking into account the different clinical departments and the different hospitals involved. Conclusions: The approach proved to be useful to understand the HCO risk structure in terms of frequency, severity, expected and unexpected loss related to adverse events. PMID:23615898

Dalle Carbonare, S; Folli, F; Patrini, E; Giudici, P; Bellazzi, R

2013-04-24

119

Integrating qualitative and quantitative methods in research on international entrepreneurship  

Microsoft Academic Search

Using mixed methods is an often proposed but rarely used research design. In this paper, I describe a mixed method approach\\u000a to research on international entrepreneurship. Using a mixed methods design with a case study and a mail survey, I show how\\u000a the two methods make it possible to reach a better understanding of the antecedents of organizational memory and

Jukka Hohenthal

2006-01-01

120

An ECL-PCR method for quantitative detection of point mutation  

NASA Astrophysics Data System (ADS)

A new method for identification of point mutations was proposed. Polymerase chain reaction (PCR) amplification of a sequence from genomic DNA was followed by digestion with a kind of restriction enzyme, which only cut the wild-type amplicon containing its recognition site. Reaction products were detected by electrochemiluminescence (ECL) assay after adsorption of the resulting DNA duplexes to the solid phase. One strand of PCR products carries biotin to be bound on a streptavidin-coated microbead for sample selection. Another strand carries Ru(bpy)32+ (TBR) to react with tripropylamine (TPA) to emit light for ECL detection. The method was applied to detect a specific point mutation in H-ras oncogene in T24 cell line. The results show that the detection limit for H-ras amplicon is 100 fmol and the linear range is more than 3 orders of magnitude, thus, make quantitative analysis possible. The genotype can be clearly discriminated. Results of the study suggest that ECL-PCR is a feasible quantitative method for safe, sensitive and rapid detection of point mutation in human genes.

Zhu, Debin; Xing, Da; Shen, Xingyan; Chen, Qun; Liu, Jinfeng

2005-04-01

121

A simplified method to create quantitative, "fixed" uranyl-contaminated metal coupons.  

PubMed

A method was developed and validated to quantitatively apply and "fix" uranyl contamination onto a metal surface (steel). Simple approaches are needed to create test surfaces in order to quantify contaminant removal or "decon" methods. We used steel discs sized to allow direct and accurate alpha counting in a Ludlum scanner from radioactive contaminants. A typical 3.8-cm-diameter coupon had a depleted uranyl loading of about 0.1 mg U cm with a count of 980 dpm. The resulting alpha radiation was measured with a precision of >97% for the same coupon. The alpha concentration on replicate coupons differed by as much as 9% (standard deviation). This method, based on earlier methods, required a uranyl solution to be dried but lowers the baking temperature to less than 100 degrees C to increase safety in a typical radiological laboratory. A dike was used to provide a uniform coating of the uranyl solution. PMID:15069301

McKeown, Catherine K; Davison, Brian H

2004-05-01

122

Laboratory methods to improve SELDI peak detection and quantitation  

PubMed Central

Background Protein profiling with surface-enhanced laser desorption-ionisation time-of-flight mass spectrometry (SELDI-TOF MS) is a promising approach for biomarker discovery. Some candidate biomarkers have been identified using SELDI-TOF, but validation of these can be challenging because of technical parameters that effect reproducibility. Here we describe steps to improve the reproducibility of peak detection. Methods SELDI-TOF mass spectrometry was performed using a system manufactured by Ciphergen Biosystems along with their ProteinChip System. Serum from 10 donors was pooled and used for all experiments. Serum was fractionated with Expression Difference Mapping kit-Serum Fractionation from the same company and applied to three different ProteinChips. The fractionations were run over a one month period to examine the contribution of sample batch and time to peak detection variability. Spectra were processed and peaks detected using the Ciphergen Express software and variance measured. Results Experimental parameters specific to the serum fraction and ProteinChip, including spot protocols (laser intensity and detector sensitivity) were optimized to decrease peak detection variance. Optimal instrument settings, regular calibration along with controlled sample handling and processing nearly doubled the number of peaks detected and decreased intensity variance. Conclusion This report assesses the variation across fractionated sera processed over a one-month period. The optimizations reported decreased the variance and increased the number of peaks detected.

Rollin, Dominique; Whistler, Toni; Vernon, Suzanne D

2007-01-01

123

A method of quantitative risk assessment for transmission pipeline carrying natural gas  

Microsoft Academic Search

Regulatory authorities in many countries are moving away from prescriptive approaches for keeping natural gas pipelines safe. As an alternative, risk management based on a quantitative assessment is being considered to improve the level of safety. This paper focuses on the development of a simplified method for the quantitative risk assessment for natural gas pipelines and introduces parameters of fatal

Young-Do Jo; Bum Jong Ahn

2005-01-01

124

Determination of haem derivatives in the cerebrospinal fluid--a semi-quantitative method.  

PubMed Central

A spectrophotometric method for semi-quantitative determination of oxyhaemoglobin, methaemoglobin and bilirubin in the cerebrospinal fluid is described and evaluated. The method involves correction for CSF protein. It is based on absorbance registrations on three wavelengths; 400, 420 and 470 nm. Reference values for a healthy control group and a hyperbilirubinaemic group are presented. Evaluation of the method shows that it is well suited to semi-quantitative determination of haem derivatives in the CSF.

Wahlgren, N G; Bergstrom, K

1983-01-01

125

Uncertainty in environmental health impact assessment: quantitative methods and perspectives.  

PubMed

Environmental health impact assessment models are subjected to great uncertainty due to the complex associations between environmental exposures and health. Quantifying the impact of uncertainty is important if the models are used to support health policy decisions. We conducted a systematic review to identify and appraise current methods used to quantify the uncertainty in environmental health impact assessment. In the 19 studies meeting the inclusion criteria, several methods were identified. These were grouped into random sampling methods, second-order probability methods, Bayesian methods, fuzzy sets, and deterministic sensitivity analysis methods. All 19 studies addressed the uncertainty in the parameter values but only 5 of the studies also addressed the uncertainty in the structure of the models. None of the articles reviewed considered conceptual sources of uncertainty associated with the framing assumptions or the conceptualisation of the model. Future research should attempt to broaden the way uncertainty is taken into account in environmental health impact assessments. PMID:22515647

Mesa-Frias, Marco; Chalabi, Zaid; Vanni, Tazio; Foss, Anna M

2012-04-19

126

Potentiometric Titration Method for Quantitative Determination of Hydrogen Peroxide.  

National Technical Information Service (NTIS)

An electrochemical potentiometric titration method that entails titration of a known volume of a catholyte containing an unknown amount of hydrogen peroxide in a titration cell having two electrodes, a platinum working electrode and a silver/silver chlori...

R. R. Bessette

2005-01-01

127

Quantitative Analysis of Single Particle Trajectories: Mean Maximal Excursion Method  

PubMed Central

An increasing number of experimental studies employ single particle tracking to probe the physical environment in complex systems. We here propose and discuss what we believe are new methods to analyze the time series of the particle traces, in particular, for subdiffusion phenomena. We discuss the statistical properties of mean maximal excursions (MMEs), i.e., the maximal distance covered by a test particle up to time t. Compared to traditional methods focusing on the mean-squared displacement we show that the MME analysis performs better in the determination of the anomalous diffusion exponent. We also demonstrate that combination of regular moments with moments of the MME method provides additional criteria to determine the exact physical nature of the underlying stochastic subdiffusion processes. We put the methods to test using experimental data as well as simulated time series from different models for normal and anomalous dynamics such as diffusion on fractals, continuous time random walks, and fractional Brownian motion.

Tejedor, Vincent; Benichou, Olivier; Voituriez, Raphael; Jungmann, Ralf; Simmel, Friedrich; Selhuber-Unkel, Christine; Oddershede, Lene B.; Metzler, Ralf

2010-01-01

128

Quantitative analysis of single particle trajectories: mean maximal excursion method.  

PubMed

An increasing number of experimental studies employ single particle tracking to probe the physical environment in complex systems. We here propose and discuss what we believe are new methods to analyze the time series of the particle traces, in particular, for subdiffusion phenomena. We discuss the statistical properties of mean maximal excursions (MMEs), i.e., the maximal distance covered by a test particle up to time t. Compared to traditional methods focusing on the mean-squared displacement we show that the MME analysis performs better in the determination of the anomalous diffusion exponent. We also demonstrate that combination of regular moments with moments of the MME method provides additional criteria to determine the exact physical nature of the underlying stochastic subdiffusion processes. We put the methods to test using experimental data as well as simulated time series from different models for normal and anomalous dynamics such as diffusion on fractals, continuous time random walks, and fractional Brownian motion. PMID:20371337

Tejedor, Vincent; Bénichou, Olivier; Voituriez, Raphael; Jungmann, Ralf; Simmel, Friedrich; Selhuber-Unkel, Christine; Oddershede, Lene B; Metzler, Ralf

2010-04-01

129

Reliability of copper reduction methods for quantitation of glucosuria  

Microsoft Academic Search

Summary  In the present study we evaluated the reliability of the ‘2-drop’ Clinitest method in determining the 24-h glucose spill of\\u000a a diabetic patient. The urine glucose content over the 33 day study period was also measured with a Beckman glucose analyzer\\u000a that employed a glucose oxidase method. There was no statistical difference between the glucose content determined by the\\u000a two

James W. Plonk; Jerome M. Feldman

1976-01-01

130

Catenation: Quantitative methods for the definition of coenoclines  

Microsoft Academic Search

Summary  Catenation is defined as the ordering of elements in continuous sequences that best accounts for local similarities without\\u000a assuming linear relations. It is thus a non-linear relative of ordination. When applied to phytosociological data it is equivalent\\u000a to the detection and definition of coenoclines.\\u000a \\u000a Several mathematical methods of catenation are available and potentially useful in phytosociology. One such method, continuity

Imanuel Noy-Meir

1974-01-01

131

Limitations of the ferrozine method for quantitative assay of mineral systems for ferrous and total iron  

NASA Astrophysics Data System (ADS)

The quantitative assay of clay minerals, soils, and sediments for Fe(II) and total Fe is fundamental to understanding biogeochemical cycles occurring therein. The commonly used ferrozine method was originally designed to assay extracted forms of Fe(II) from non-silicate aqueous systems. It is becoming, however, increasingly the method of choice to report the total reduced state of Fe in soils and sediments. Because Fe in soils and sediments commonly exists in the structural framework of silicates, extraction by HCl, as used in the ferrozine method, fails to dissolve all of the Fe. The phenanthroline (phen) method, on the other hand, was designed to assay silicate minerals for Fe(II) and total Fe and has been proven to be highly reliable. In the present study potential sources of error in the ferrozine method were evaluated by comparing its results to those obtained by the phen method. Both methods were used to analyze clay mineral and soil samples for Fe(II) and total Fe. Results revealed that the conventional ferrozine method under reports total Fe in samples containing Fe in silicates and gives erratic results for Fe(II). The sources of error in the ferrozine method are: (1) HCl fails to dissolve silicates and (2) if the analyte solution contains Fe 3+, the analysis for Fe 2+ will be photosensitive, and reported Fe(II) values will likely be greater than the actual amount in solution. Another difficulty with the ferrozine method is that it is tedious and much more labor intensive than the phen method. For these reasons, the phen method is preferred and recommended. Its procedure is simpler, takes less time, and avoids the errors found in the ferrozine method.

Anastácio, Alexandre S.; Harris, Brittany; Yoo, Hae-In; Fabris, José Domingos; Stucki, Joseph W.

2008-10-01

132

Quantitative trait locus gene mapping: a new method for locating alcohol response genes.  

PubMed

Alcoholism is a multigenic trait with important non-genetic determinants. Studies with genetic animal models of susceptibility to several of alcohol's effects suggest that several genes contributing modest effects on susceptibility (Quantitative Trait Loci, or QTLs) are important. A new technique of QTL gene mapping has allowed the identification of the location in mouse genome of several such QTLs. The method is described, and the locations of QTLs affecting the acute alcohol withdrawal reaction are described as an example of the method. Verification of these QTLs in ancillary studies is described and the strengths, limitations, and future directions to be pursued are discussed. QTL mapping is a promising method for identifying genes in rodents with the hope of directly extrapolating the results to the human genome. This review is based on a paper presented at the First International Congress of the Latin American Society for Biomedical Research on Alcoholism, Santiago, Chile, November 1994. PMID:12893462

Crabbe, J C

1996-01-01

133

Stress echocardiography: methods, indications and results  

PubMed Central

Stress echocardiography has become an important clinical tool to detect cardiac ischaemia and viability in addition to single photon emission tomography. Stress echocardiography has a high positive and negative predictive value, is less expensive than the nuclear methods and has no radiation exposure. It can easily be used in an emergency room and coronary care unit. Because of its feasibility, low cost and high diagnostic accuracy, it will become a very important technique in every hospital and will soon be a real alternative to the more time-consuming and expensive nuclear techniques. The current article gives a review of the methods of stress echocardiography. ImagesFigure 2Figure 3Figure 4

Baur, L.H.B.

2002-01-01

134

QUANTITATIVE CANCER RISK ASSESSMENT METHODOLOGY USING SHORT-TERM GENETIC BIOASSAYS: THE COMPARATIVE POTENCY METHOD  

EPA Science Inventory

Quantitative risk assessment is fraught with many uncertainties. The validity of the assumptions underlying the methods employed are often difficult to test or validate. Cancer risk assessment has generally employed either human epidemiological data from relatively high occupatio...

135

A New Method for Quantitative Real-Time Polymerase Chain Reaction Data Analysis  

PubMed Central

Abstract Quantitative real-time polymerase chain reaction (qPCR) is a sensitive gene quantification method that has been extensively used in biological and biomedical fields. The currently used methods for PCR data analysis, including the threshold cycle method and linear and nonlinear model-fitting methods, all require subtracting background fluorescence. However, the removal of background fluorescence can hardly be accurate and therefore can distort results. We propose a new method, the taking-difference linear regression method, to overcome this limitation. Briefly, for each two consecutive PCR cycles, we subtract the fluorescence in the former cycle from that in the latter cycle, transforming the n cycle raw data into n?1 cycle data. Then, linear regression is applied to the natural logarithm of the transformed data. Finally, PCR amplification efficiencies and the initial DNA molecular numbers are calculated for each reaction. This taking-difference method avoids the error in subtracting an unknown background, and thus it is more accurate and reliable. This method is easy to perform, and this strategy can be extended to all current methods for PCR data analysis.

Rao, Xiayu; Lai, Dejian

2013-01-01

136

Characterization of working iron Fischer-Tropsch catalysts using quantitative diffraction methods  

NASA Astrophysics Data System (ADS)

This study presents the results of the ex-situ characterization of working iron Fischer-Tropsch synthesis (F-TS) catalysts, reacted hundreds of hours at elevated pressures, using a new quantitative x-ray diffraction analytical methodology. Compositions, iron phase structures, and phase particle morphologies were determined and correlated with the observed reaction kinetics. Conclusions were drawn about the character of each catalyst in its most and least active state. The identity of the active phase(s) in the Fe F-TS catalyst has been vigorously debated for more than 45 years. The highly-reduced catalyst, used to convert coal-derived syngas to hydrocarbon products, is thought to form a mixture of oxides, metal, and carbides upon pretreatment and reaction. Commonly, Soxhlet extraction is used to effect catalyst-product slurry separation; however, the extraction process could be producing irreversible changes in the catalyst, contributing to the conflicting results in the literature. X-ray diffraction doesn't require analyte-matrix separation before analysis, and can detect trace phases down to 300 ppm/2 nm; thus, working catalyst slurries could be characterized as-sampled. Data were quantitatively interpreted employing first principles methods, including the Rietveld polycrystalline structure method. Pretreated catalysts and pure phases were examined experimentally and modeled to explore specific behavior under x-rays. Then, the working catalyst slurries were quantitatively characterized. Empirical quantitation factors were calculated from experimental data or single crystal parameters, then validated using the Rietveld method results. In the most active form, after pretreatment in H 2 or in CO at Pambient, well-preserved working catalysts contained significant amounts of Fe7C3 with trace alpha-Fe, once reaction had commenced at elevated pressure. Amounts of Fe3O 4 were constant and small, with carbide dpavg < 15 nm. Small amounts of Fe7C3 were found in unreacted catalyst pretreated in CO at elevated pressures. In the least active form, well-preserved working catalysts contained Fe5C2 amounts >65 wt%, regardless of pretreatment gas and pressure, with all dpavg 18 nm. epsilon '-Fe2.2C carbide was found to probably consist of an {Fe5C2/FexO/epsilon-Fe3C} mixture. Fe5C2 carbide exhibited wide variations in diffraction pattern which could be correlated with sample handling events, changes in process conditions, or dpavg.

Mansker, Linda Denise

137

A novel real-time quantitative PCR method using attached universal template probe  

PubMed Central

A novel real-time quantitative polymerase chain reaction (PCR) method using an attached universal template (UT) probe is described. The UT is an approximately 20 base attachment to the 5? end of a PCR primer, and it can hybridize with a complementary TaqMan probe. One of the advantages of this method is that different target DNA sequences can be detected employing the same UT probe, which substantially reduces the cost of real-time PCR set-up. In addition, this method could be used for simultaneous detection using a 6-carboxy-fluorescein-labeled UT probe for the target gene and a 5-hexachloro-fluorescein-labeled UT probe for the reference gene in a multiplex reaction. Moreover, the requirement of target DNA length for UT–PCR analysis is relatively flexible, and it could be as short as 56 bp in this report, suggesting the possibility of detecting target DNA from partially degraded samples. The UT–PCR system with degenerate primers could also be designed to screen homologous genes. Taken together, our results suggest that the UT–PCR technique is efficient, reliable, inexpensive and less labor-intensive for quantitative PCR analysis.

Zhang, Yuanli; Zhang, Dabing; Li, Wenquan; Chen, Jianqun; Peng, Yufa; Cao, Wei

2003-01-01

138

Quantitative method for measurement of the Goos-Hanchen effect based on source divergence considerations  

SciTech Connect

In this paper we report on a method for quantitative measurement and characterization of the Goos-Hanchen effect based upon the real world performance of optical sources. A numerical model of a nonideal plane wave is developed in terms of uniform divergence properties. This model is applied to the Goos-Hanchen shift equations to determine beam shift displacement characteristics, which provides quantitative estimates of finite shifts near critical angle. As a potential technique for carrying out a meaningful comparison with experiments, a classical method of edge detection is discussed. To this end a line spread Green's function is defined which can be used to determine the effective transfer function of the near critical angle behavior of divergent plane waves. The process yields a distributed (blurred) output with a line spread function characteristic of the inverse square root nature of the Goos-Hanchen shift equation. A parameter of interest for measurement is given by the edge shift function. Modern imaging and image processing methods provide suitable techniques for exploiting the edge shift phenomena to attain refractive index sensitivities of the order of 10{sup -6}, comparable with the recent results reported in the literature.

Gray, Jeffrey F.; Puri, Ashok [Department of Electrical Engineering, University of New Orleans, New Orleans, Louisiana 70148 (United States); Department of Physics, University of New Orleans, New Orleans, Louisiana 70148 (United States)

2007-06-15

139

Composition and Quantitation of Microalgal Lipids by ERETIC 1H NMR Method.  

PubMed

Accurate characterization of biomass constituents is a crucial aspect of research in the biotechnological application of natural products. Here we report an efficient, fast and reproducible method for the identification and quantitation of fatty acids and complex lipids (triacylglycerols, glycolipids, phospholipids) in microalgae under investigation for the development of functional health products (probiotics, food ingredients, drugs, etc.) or third generation biofuels. The procedure consists of extraction of the biological matrix by modified Folch method and direct analysis of the resulting material by proton nuclear magnetic resonance (1H NMR). The protocol uses a reference electronic signal as external standard (ERETIC method) and allows assessment of total lipid content, saturation degree and class distribution in both high throughput screening of algal collection and metabolic analysis during genetic or culturing studies. As proof of concept, the methodology was applied to the analysis of three microalgal species (Thalassiosira weissflogii, Cyclotella cryptica and Nannochloropsis salina) which drastically differ for the qualitative and quantitative composition of their fatty acid-based lipids. PMID:24084790

Nuzzo, Genoveffa; Gallo, Carmela; d'Ippolito, Giuliana; Cutignano, Adele; Sardo, Angela; Fontana, Angelo

2013-09-30

140

Simple spectrophotocolorimetric method for quantitative determination of gold in nanoparticles.  

PubMed

A simple spectrophotocolorimetric method devoted to the measurement of gold content in nanoparticles (NPs) was developed. It includes two steps: (i) metal gold NPs (Au NPs) are oxidized into the AuCl(4)(-) anion using a 5×10(-2) M HCl-1.5×10(-2) M NaCl-7×10(-4) M Br(2) solution, next (ii) AuCl(4)(-) concentration is measured using a spectrophotometric assay based on the reaction of AuCl(4)(-) with the cationic form of Rhodamine B to give a violet ion pair complex. This latter is extracted with diisopropyl ether and the absorbance of the organic complex is measured at 565 nm. The method is linear in the range 6-29 ?M of AuCl(4)(-) with a limit of detection of 4.5?M. The analytical method was optimized with respect of bromine excess to obtain complete Au NPs oxidation. The method was applied to two types of Au NPs currently under investigation: citrate-stabilized Au NPs and Au NPs capped with dihydrolipoic acid (Au@DHLA). Both the gold content of Au NPs and the concentration of NPs (using NP diameter measured by transmission electron microscopy) have been calculated. PMID:21238784

Tournebize, Juliana; Sapin-Minet, Anne; Schneider, Raphaël; Boudier, Ariane; Maincent, Philippe; Leroy, Pierre

2010-12-13

141

A review of quantitative methods for movement data  

Microsoft Academic Search

The collection, visualization, and analysis of movement data is at the forefront of geographic information science research. Movement data are generally collected by recording an object's spatial location (e.g., XY coordinates) at discrete time intervals. Methods for extracting useful information, for example space–time patterns, from these increasingly large and detailed datasets have lagged behind the technology for generating them. In

Jed A. Long; Trisalyn A. Nelson

2012-01-01

142

A new risk assessment quantitative method based on fuzzy AHP  

Microsoft Academic Search

With the development of the country and the acceleration of information technology, the information security issues is highly growing. In order to efficiently evaluate the information security risk, the information system security risk assessment model based on Fuzzy AHP method is proposed. In this paper, firstly, we use multi-layer structure and elation matrix is introduced to describe the interrelationship among

Wang Lijian; Wang Bin; Peng Yongjun

2010-01-01

143

Bioanalytical methods for quantitation of levamisole, a widespread cocaine adulterant.  

PubMed

Abstract Levamisole is an anthelminthic that was first used as a de-worming agent in humans and animals. It has also been used to treat inflammatory conditions as well as certain types of cancer. Levamisole was discontinued for human use in the early 21st century due to toxic side effects including agranulocytosis and vasculitis. Recently, levamisole was discovered as a cocaine adulterant after reports emerged of drug users with the above disorders. As the prevalence of cocaine usage has grown in the last 15 years, measurement of levamisole in human samples has become increasingly important. This review focuses on the various bioanalytical methods available for the determination of levamisole in human plasma and urine. Earlier methods employed gas chromatography coupled with nitrogen-selective thermionic specific detection and nitrogen-phosphorus detection, as well as high performance liquid chromatography coupled with ultraviolet detection. In addition, gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) have also been described. Currently, GC-MS appears to be the method of choice however recent developments in the area of LC-MS/MS make this technology an attractive alternative. The merits of both GC-MS and LC-MS/MS for the determination of levamisole are evaluated on the basis of sample preparation, chromatographic separation conditions, run time, and analytical performance. In addition, emerging methods in this area are also reviewed. PMID:23152411

Shea, Jennifer L

2013-01-01

144

The need for quantitative methods in syntax and semantics research  

Microsoft Academic Search

The prevalent method in syntax and semantics research involves obtaining a judgement of the acceptability of a sentence\\/meaning pair, typically by just the author of the paper, sometimes with feedback from colleagues. This methodology does not allow proper testing of scientific hypotheses because of (a) the small number of experimental participants (typically one); (b) the small number of experimental stimuli

Edward Gibson; Evelina Fedorenko

2010-01-01

145

A Quantitative Diagnostic Method Based on Bayesian Networks in Traditional Chinese Medicine  

Microsoft Academic Search

\\u000a Traditional Chinese Medicine (TCM) is one of the most important complementary and alternative medicines. Due to the subjectivity\\u000a and fuzziness of diagnosis in TCM, quantitative model or methods are needed to facilitate the popularization of TCM. In this\\u000a article, a novel quantitative method for syndrome differentiation based on BNs is proposed. First the symptoms are selected\\u000a by a novel mutual

Huiyan Wang; Jie Wang

2006-01-01

146

Quantitative HPLC-UV method for the determination of firocoxib from horse and dog plasma  

Microsoft Academic Search

A sensitive reversed-phase HPLC-UV method was developed for the determination of firocoxib, a novel and highly selective COX-2 inhibitor, in plasma. A 1.0mL dog or horse plasma sample is mixed with water and passed through a hydrophobic–lipophilic copolymer solid-phase extraction column to isolate firocoxib. Quantitation is based on an external standard curve. The method has a validated limit of quantitation

Valerie Kvaternick; Thomas Malinski; Jill Wortmann; James Fischer

2007-01-01

147

Functionally oriented and clinically feasible quantitative gait analysis method  

Microsoft Academic Search

A protocol for clinical gait analysis is described, and data from 30 normal adult female subjects are presented. Extensive\\u000a application to pathologic subjects has proven to be feasible and sufficiently accurate. The method is based on a particular\\u000a location and attachment of retro-reflective markers on the body and on a particular arrangement of four TV cameras. A motion\\u000a analyser measures

C. Frigo; M. Rabuffetti; D. C. Kerrigan; L. C. Deming; A. Pedotti

1998-01-01

148

A quantitative method for the analysis of ternary systems  

Microsoft Academic Search

The rapid determination is reported of the concentrations of K+, Co2+ and Pb2+ in a ternary system. The method used is based on the measurement of the activity of the solution containing a labelled component,\\u000a and on the determination of the intensity of ?-rays back-scattered in the system. Standard curves are drawn, by means of which\\u000a the unknown concentrations of

A. Cecal

1972-01-01

149

Nutritional status in Europe: methods and results.  

PubMed

Presented here is an analysis and documentation of the nutritional situation in 14 European countries. Collection methods and available data about the most common nutritional status assessment indicators are described. Prevalence of adult obesity varied considerably in the 14 countries, ranging from 6% to 31%. The mean fat intake of adults exceeded the population goal of less than 30% of energy in virtually all of the 14 countries. Dietary fiber, folate, vitamin D, and (excessive) sodium intake did not meet recommended levels. Strategies addressing the inadequacies in European diets are needed to improve the nutritional situation in Europe. PMID:19453667

Elmadfa, Ibrahim; Freisling, Heinz

2009-05-01

150

Facilitating arrhythmia simulation: the method of quantitative cellular automata modeling and parallel running  

PubMed Central

Background Many arrhythmias are triggered by abnormal electrical activity at the ionic channel and cell level, and then evolve spatio-temporally within the heart. To understand arrhythmias better and to diagnose them more precisely by their ECG waveforms, a whole-heart model is required to explore the association between the massively parallel activities at the channel/cell level and the integrative electrophysiological phenomena at organ level. Methods We have developed a method to build large-scale electrophysiological models by using extended cellular automata, and to run such models on a cluster of shared memory machines. We describe here the method, including the extension of a language-based cellular automaton to implement quantitative computing, the building of a whole-heart model with Visible Human Project data, the parallelization of the model on a cluster of shared memory computers with OpenMP and MPI hybrid programming, and a simulation algorithm that links cellular activity with the ECG. Results We demonstrate that electrical activities at channel, cell, and organ levels can be traced and captured conveniently in our extended cellular automaton system. Examples of some ECG waveforms simulated with a 2-D slice are given to support the ECG simulation algorithm. A performance evaluation of the 3-D model on a four-node cluster is also given. Conclusions Quantitative multicellular modeling with extended cellular automata is a highly efficient and widely applicable method to weave experimental data at different levels into computational models. This process can be used to investigate complex and collective biological activities that can be described neither by their governing differentiation equations nor by discrete parallel computation. Transparent cluster computing is a convenient and effective method to make time-consuming simulation feasible. Arrhythmias, as a typical case, can be effectively simulated with the methods described.

Zhu, Hao; Sun, Yan; Rajagopal, Gunaretnam; Mondry, Adrian; Dhar, Pawan

2004-01-01

151

A novel generalized ridge regression method for quantitative genetics.  

PubMed

As the molecular marker density grows, there is a strong need in both genome-wide association studies and genomic selection to fit models with a large number of parameters. Here we present a computationally efficient generalized ridge regression (RR) algorithm for situations in which the number of parameters largely exceeds the number of observations. The computationally demanding parts of the method depend mainly on the number of observations and not the number of parameters. The algorithm was implemented in the R package bigRR based on the previously developed package hglm. Using such an approach, a heteroscedastic effects model (HEM) was also developed, implemented, and tested. The efficiency for different data sizes were evaluated via simulation. The method was tested for a bacteria-hypersensitive trait in a publicly available Arabidopsis data set including 84 inbred lines and 216,130 SNPs. The computation of all the SNP effects required <10 sec using a single 2.7-GHz core. The advantage in run time makes permutation test feasible for such a whole-genome model, so that a genome-wide significance threshold can be obtained. HEM was found to be more robust than ordinary RR (a.k.a. SNP-best linear unbiased prediction) in terms of QTL mapping, because SNP-specific shrinkage was applied instead of a common shrinkage. The proposed algorithm was also assessed for genomic evaluation and was shown to give better predictions than ordinary RR. PMID:23335338

Shen, Xia; Alam, Moudud; Fikse, Freddy; Rönnegård, Lars

2013-01-18

152

Quantitative comparison of segmentation methods for in-body images  

Microsoft Academic Search

In this paper, we present a numerical comparison of how well segmentation algorithms approximate the manual segmentation of gastroenterologists for a set of endoscopic images. Different areas in these images demand different levels of analysis by a clinician and some provide critical information about the patient. Our objective is thus to segment endoscopic images so that the results mimic as

Farhan Riaz; Mario Dinis Ribeiro; Miguel Tavares Coimbra

2009-01-01

153

Quantitative mineralogical composition of complex mineral wastes - Contribution of the Rietveld method  

SciTech Connect

The objective of the work presented in this paper is the quantitative determination of the mineral composition of two complex mineral wastes: a sewage sludge ash (SSA) and a municipal solid waste incineration fly ash (MSWIFA). The mineral compositions were determined by two different methods: the first based on calculation using the qualitative mineralogical composition of the waste combined with physicochemical analyses; the second the Rietveld method, which uses only X-ray diffraction patterns. The results obtained are coherent, showing that it is possible to quantify the mineral compositions of complex mineral waste with such methods. The apparent simplicity of the Rietveld method (due principally to the availability of software packages implementing the method) facilitates its use. However, care should be taken since the crystal structure analysis based on powder diffraction data needs experience and a thorough understanding of crystallography. So the use of another, complementary, method such as the first one used in this study, may sometimes be needed to confirm the results.

Mahieux, P.-Y. [Universite de Toulouse, UPS, INSA, LMDC (Laboratoire Materiaux et Durabilite des Constructions), 135, Avenue de Rangueil, F-31 077 Toulouse Cedex 4 (France); Aubert, J.-E., E-mail: aubert@insa-toulouse.f [Universite de Toulouse, UPS, INSA, LMDC (Laboratoire Materiaux et Durabilite des Constructions), 135, Avenue de Rangueil, F-31 077 Toulouse Cedex 4 (France); Cyr, M.; Coutand, M.; Husson, B. [Universite de Toulouse, UPS, INSA, LMDC (Laboratoire Materiaux et Durabilite des Constructions), 135, Avenue de Rangueil, F-31 077 Toulouse Cedex 4 (France)

2010-03-15

154

Evaluating Attitudes, Skill, and Performance in a Learning-Enhanced Quantitative Methods Course: A Structural Modeling Approach.  

ERIC Educational Resources Information Center

|Used a structural modeling approach to evaluate relations among attitudes, initial skills, and performance in a Quantitative Methods course that involved students in active learning. Results largely confirmed hypotheses offering support for educational reform efforts that propose actively involving students in the learning process, especially in…

Harlow, Lisa L.; Burkholder, Gary J.; Morrow, Jennifer A.

2002-01-01

155

RE-EXAMINATION OF THE STATISTICAL METHODS USED TO DETERMINE THE NUMBER OF POINT COUNTS NEEDED FOR MICROPALEONTOLOGICAL QUANTITATIVE RESEARCH  

Microsoft Academic Search

Currently some controversy exists in the micropaleontological community concerning the statistically correct number of counts required for quantitative examinations, particularly with respect to the effect of variations in the number ofspedes between samples and the significance of varying fractional abundances on the reliability of results, This analysis of the various statistical methods used to determine the number of required counts

R. TIMOTHY PATTERSON; EVAN FISHBEIN

1989-01-01

156

Methods Used by Pre-Service Nigeria Certificate in Education Teachers in Solving Quantitative Problems in Chemistry  

ERIC Educational Resources Information Center

|This paper reports part of the results of research on chemical problem solving behavior of pre-service teachers in Plateau and Northeastern states of Nigeria. Specifically, it examines and describes the methods used by 204 pre-service teachers in solving quantitative problems from four topics in chemistry. Namely, gas laws; electrolysis;…

Danjuma, Ibrahim Mohammed

2011-01-01

157

Methods and results of rhinophyma treatment.  

PubMed

Rhinophyma is a disfiguring soft-tissue hypertrophy of the nose. It is an uncommon disease that primarily affects Caucasian men in the fifth to seventh decades of life. Nine cases from the authors' series and a comparison of results following various treatment modalities are presented. Eight of the patients were Caucasian and one was African American. Excision of the diseased tissue with a scalpel or Goulian dermatome using loupe magnification provided the safest means of preserving the underlying sebaceous gland fundi that permit spontaneous re-epithelialization with the least scarring. PMID:11373550

Redett, R J; Manson, P N; Goldberg, N; Girotto, J; Spence, R J

2001-04-15

158

Radioisotopic neutron transmission spectrometry: Quantitative analysis by using partial least-squares method.  

PubMed

Neutron spectrometry, based on the scattering of high energy fast neutrons from a radioisotope and slowing-down by the light hydrogen atoms, is a useful technique for non-destructive, quantitative measurement of hydrogen content because it has a large measuring volume, and is not affected by temperature, pressure, pH value and color. The most common choice for radioisotope neutron source is (252)Cf or (241)Am-Be. In this study, (252)Cf with a neutron flux of 6.3x10(6)n/s has been used as an attractive neutron source because of its high flux neutron and weak radioactivity. Pulse-height neutron spectra have been obtained by using in-house built radioisotopic neutron spectrometric system equipped with (3)He detector and multi-channel analyzer, including a neutron shield. As a preliminary study, polyethylene block (density of approximately 0.947g/cc and area of 40cmx25cm) was used for the determination of hydrogen content by using multivariate calibration models, depending on the thickness of the block. Compared with the results obtained from a simple linear calibration model, partial least-squares regression (PLSR) method offered a better performance in a quantitative data analysis. It also revealed that the PLSR method in a neutron spectrometric system can be promising in the real-time, online monitoring of the powder process to determine the content of any type of molecules containing hydrogen nuclei. PMID:19285419

Kim, Jong-Yun; Choi, Yong Suk; Park, Yong Joon; Jung, Sung-Hee

2009-02-20

159

"Per cell" normalization method for mRNA measurement by quantitative PCR and microarrays  

PubMed Central

Background Transcriptome data from quantitative PCR (Q-PCR) and DNA microarrays are typically obtained from a fixed amount of RNA collected per sample. Therefore, variations in tissue cellularity and RNA yield across samples in an experimental series compromise accurate determination of the absolute level of each mRNA species per cell in any sample. Since mRNAs are copied from genomic DNA, the simplest way to express mRNA level would be as copy number per template DNA, or more practically, as copy number per cell. Results Here we report a method (designated the "Percellome" method) for normalizing the expression of mRNA values in biological samples. It provides a "per cell" readout in mRNA copy number and is applicable to both quantitative PCR (Q-PCR) and DNA microarray studies. The genomic DNA content of each sample homogenate was measured from a small aliquot to derive the number of cells in the sample. A cocktail of five external spike RNAs admixed in a dose-graded manner (dose-graded spike cocktail; GSC) was prepared and added to each homogenate in proportion to its DNA content. In this way, the spike mRNAs represented absolute copy numbers per cell in the sample. The signals from the five spike mRNAs were used as a dose-response standard curve for each sample, enabling us to convert all the signals measured to copy numbers per cell in an expression profile-independent manner. A series of samples was measured by Q-PCR and Affymetrix GeneChip microarrays using this Percellome method, and the results showed up to 90 % concordance. Conclusion Percellome data can be compared directly among samples and among different studies, and between different platforms, without further normalization. Therefore, "percellome" normalization can serve as a standard method for exchanging and comparing data across different platforms and among different laboratories.

Kanno, Jun; Aisaki, Ken-ichi; Igarashi, Katsuhide; Nakatsu, Noriyuki; Ono, Atsushi; Kodama, Yukio; Nagao, Taku

2006-01-01

160

A practical and sensitive method of quantitating lymphangiogenesis in vivo.  

PubMed

To address the inadequacy of current assays, we developed a directed in vivo lymphangiogenesis assay (DIVLA) by modifying an established directed in vivo angiogenesis assay. Silicon tubes (angioreactors) were implanted in the dorsal flanks of nude mice. Tubes contained either growth factor-reduced basement membrane extract (BME)-alone (negative control) or BME-containing vascular endothelial growth factor (VEGF)-D (positive control for lymphangiogenesis) or FGF-2/VEGF-A (positive control for angiogenesis) or a high VEGF-D-expressing breast cancer cell line MDA-MD-468LN (468-LN), or VEGF-D-silenced 468LN. Lymphangiogenesis was detected superficially with Evans Blue dye tracing and measured in the cellular contents of angioreactors by multiple approaches: lymphatic vessel endothelial hyaluronan receptor-1 (Lyve1) protein (immunofluorescence) and mRNA (qPCR) expression and a visual scoring of lymphatic vs blood capillaries with dual Lyve1 (or PROX-11 or Podoplanin)/Cd31 immunostaining in cryosections. Lymphangiogenesis was absent with BME, high with VEGF-D or VEGF-D-producing 468LN cells and low with VEGF-D-silenced 468LN. Angiogenesis was absent with BME, high with FGF-2/VEGF-A, moderate with 468LN or VEGF-D and low with VEGF-D-silenced 468LN. The method was reproduced in a syngeneic murine C3L5 tumor model in C3H/HeJ mice with dual Lyve1/Cd31 immunostaining. Thus, DIVLA presents a practical and sensitive assay of lymphangiogenesis, validated with multiple approaches and markers. It is highly suited to identifying pro- and anti-lymphangiogenic agents, as well as shared or distinct mechanisms regulating lymphangiogenesis vs angiogenesis, and is widely applicable to research in vascular/tumor biology. PMID:23711825

Majumder, Mousumi; Xin, Xiping; Lala, Peeyush K

2013-05-27

161

Smaller, scale-free gene networks increase quantitative trait heritability and result in faster population recovery.  

PubMed

One of the goals of biology is to bridge levels of organization. Recent technological advances are enabling us to span from genetic sequence to traits, and then from traits to ecological dynamics. The quantitative genetics parameter heritability describes how quickly a trait can evolve, and in turn describes how quickly a population can recover from an environmental change. Here I propose that we can link the details of the genetic architecture of a quantitative trait--i.e., the number of underlying genes and their relationships in a network--to population recovery rates by way of heritability. I test this hypothesis using a set of agent-based models in which individuals possess one of two network topologies or a linear genotype-phenotype map, 16-256 genes underlying the trait, and a variety of mutation and recombination rates and degrees of environmental change. I find that the network architectures introduce extensive directional epistasis that systematically hides and reveals additive genetic variance and affects heritability: network size, topology, and recombination explain 81% of the variance in average heritability in a stable environment. Network size and topology, the width of the fitness function, pre-change additive variance, and certain interactions account for ?75% of the variance in population recovery times after a sudden environmental change. These results suggest that not only the amount of additive variance, but importantly the number of loci across which it is distributed, is important in regulating the rate at which a trait can evolve and populations can recover. Taken in conjunction with previous research focused on differences in degree of network connectivity, these results provide a set of theoretical expectations and testable hypotheses for biologists working to span levels of organization from the genotype to the phenotype, and from the phenotype to the environment. PMID:21347400

Malcom, Jacob W

2011-02-09

162

[A potentiometric method of quantitative analysis of rifampicin].  

PubMed

A potentiometric procedure for assay of rifampicin was developed. The procedure implies titration of rifampicin as a monofunctional acid by sodium hydroxide solution (0.1 mol/l) in 75 per cent aqueous methanol. The constant ionic strength of the solution is provided by addition of KCl until its concentration is 0.1 mol/l, the titrant concentration being 10 times higher than the antibiotic concentration in the solution. This provides a precise determination of the concentration ionization constant of the antibiotic as a monofunctional acid (pKa 7.33 +/- 0.01) and an insignificant dilution of the antibiotic solution during the titration promoting precise and reproducible results. The procedure error is 0.20 per cent. The variation coefficient is 0.27 per cent. PMID:2337377

Ovcharova, G D; Nacheva, R N; Dimitrova, D B

1990-02-01

163

Statistical methods for quantitative mass spectrometry proteomic experiments with labeling  

PubMed Central

Mass Spectrometry utilizing labeling allows multiple specimens to be subjected to mass spectrometry simultaneously. As a result, between-experiment variability is reduced. Here we describe use of fundamental concepts of statistical experimental design in the labeling framework in order to minimize variability and avoid biases. We demonstrate how to export data in the format that is most efficient for statistical analysis. We demonstrate how to assess the need for normalization, perform normalization, and check whether it worked. We describe how to build a model explaining the observed values and test for differential protein abundance along with descriptive statistics and measures of reliability of the findings. Concepts are illustrated through the use of three case studies utilizing the iTRAQ 4-plex labeling protocol.

2012-01-01

164

New facility design and work method for the quantitative fit testing laboratory. Master's thesis  

SciTech Connect

The United States Air Force School of Aerospace Medicine (USAFSAM) tests the quantitative fit of masks which are worn by military personnel during nuclear, biological, and chemical warfare. Subjects are placed in a Dynatech-Frontier Fit Testing Chamber, salt air is fed into the chamber, and samples of air are drawn from the mask and the chamber. The ratio of salt air outside the mask to salt air inside the mask is called the quantitative fit factor. A motion-time study was conducted to evaluate the efficiency of the layout and work method presently used in the laboratory. A link analysis was done to determine equipment priorities, and the link data and design guidelines were used to develop three proposed laboratory designs. The proposals were evaluated by projecting the time and motion efficiency, and the energy expended working in each design. Also evaluated were the lengths of the equipment links for each proposal, and each proposal's adherence to design guidelines. A mock-up was built of the best design proposal, and a second motion-time study was run. Results showed that with the new laboratory and work procedures, the USAFSAM analyst could test 116 more subjects per year than are currently tested. Finally, the results of a questionnaire given to the analyst indicated that user acceptance of the work area improved with the new design.

Ward, G.F.

1989-05-01

165

Quantitative assessment of trabecular bone micro-architecture of the wrist via 7 Tesla MRI: preliminary results  

PubMed Central

Object The goal of this study was to determine the feasibility of performing quantitative 7T magnetic resonance imaging (MRI) assessment of trabecular bone micro-architecture of the wrist, a common fracture site. Materials and methods The wrists of 4 healthy subjects (1 woman, 3 men, 28±8.9 years) were scanned on a 7T whole body MR scanner using a 3D fast low-angle shot (FLASH) sequence (TR/TE = 20/4.5ms, 0.169 × 0.169 × 0.5mm). Trabecular bone was segmented and divided into 4 or 8 angular subregions. Total bone volume (TBV), bone volume fraction (BVF), surface-curve ratio (SC), and erosion index (EI) were computed. Subjects were scanned twice to assess measurement reproducibility. Results Group mean subregional values for TBV, BVF, SC, and EI (8 subregion analysis) were as follows: 8489 ± 3686, 0.27 ± 0.045, 9.61 ± 6.52; and 1.43 ± 1.25. Within each individual, there was subregional variation in TBV, SC, and EI (>5%), but not BVF (<5%). Intersubject variation (?12%) existed for all parameters. Within-subject coefficients of variation were ?10%. Conclusion This is the first study to perform quantitative 7T MRI assessment of trabecular bone micro-architecture of the wrist. This method could be utilized to study perturbations in bone structure in subjects with osteoporosis or other bone disorders.

Wang, Ligong; Liang, Guoyuan; Babb, James S.; Wiggins, Graham C.; Saha, Punam K.; Regatte, Ravinder R.

2013-01-01

166

mcrA-Targeted Real-Time Quantitative PCR Method To Examine Methanogen Communities  

Microsoft Academic Search

Methanogens are of great importance in carbon cycling and alternative energy production, but quantitation with culture-based methods is time-consuming and biased against methanogen groups that are difficult to cultivate in a laboratory. For these reasons, methanogens are typically studied through culture-independent molecular techniques. We developed a SYBR green I quantitative PCR (qPCR) assay to quantify total numbers of methyl coenzyme

Lisa M. Steinberg; John M. Regan

2009-01-01

167

Interferences of suspended clay fraction in protein quantitation by several determination methods  

Microsoft Academic Search

Seven current methods of protein quantitation, Bradford (standard, micro, and 590\\/450nm ratio), Lowry, bicinchoninic acid (BCA), UV spectrophotometry at 280nm, and Quant-iT fluorescence-based determination, were compared with regard to their susceptibility to interferences due to the presence of suspended and not easily detectable clay particles. Bovine serum albumin (BSA) and Na-Wyoming montmorillonite were selected as model protein and reference clay,

I. Lozzi; A. Pucci; O. L. Pantani; L. P. D’Acqui; L. Calamai

2008-01-01

168

Quantitative Method of Measuring Spot Size of Microfocus X-ray Generator  

Microsoft Academic Search

Microfocus X-ray generators have been extensively used for magnification radiography. In these applications, the sharpness of an image depends on the X-ray source size. Therefore, it is important to evaluate and optimize the X-ray spot quantitatively. Although several methods have been devised to date, some require complicated systems whereas others are not fully quantitative. Here, we introduce a simple, practical,

Hiroyuki Uchida; Kazuto Hasuike; Ken'ichi Torii; Hiroshi Tsunemi

2006-01-01

169

Improved gas chromatographic–mass spectrometric method for the quantitative determination of vinpocetine in human plasma  

Microsoft Academic Search

An improved and validated method for the determination of vinpocetine in human plasma using a combination of a solid-phase extraction as a cleaning step followed by gas chromatography–mass spectrometry (GC–MS) has been presented. Quantitation has been carried out with apovincaminic acid methyl ester as internal standard. A limit of detection of 0.01 ng\\/ml, limit of quantitation of 0.10 ng\\/ml, as

M Vatsova; S Tzvetanov; A Drenska; J Goranscheva; N Tyutyulkova

1997-01-01

170

Comparison study on qualitative and quantitative risk assessment methods for urban natural gas pipeline network.  

PubMed

In this paper, a qualitative and a quantitative risk assessment methods for urban natural gas pipeline network are proposed. The qualitative method is comprised of an index system, which includes a causation index, an inherent risk index, a consequence index and their corresponding weights. The quantitative method consists of a probability assessment, a consequences analysis and a risk evaluation. The outcome of the qualitative method is a qualitative risk value, and for quantitative method the outcomes are individual risk and social risk. In comparison with previous research, the qualitative method proposed in this paper is particularly suitable for urban natural gas pipeline network, and the quantitative method takes different consequences of accidents into consideration, such as toxic gas diffusion, jet flame, fire ball combustion and UVCE. Two sample urban natural gas pipeline networks are used to demonstrate these two methods. It is indicated that both of the two methods can be applied to practical application, and the choice of the methods depends on the actual basic data of the gas pipelines and the precision requirements of risk assessment. PMID:21402442

Han, Z Y; Weng, W G

2011-02-26

171

The use of electromagnetic induction methods for establishing quantitative permafrost models in West Greenland  

NASA Astrophysics Data System (ADS)

The sedimentary settings at West Greenlandic town and infrastructural development sites are dominated by fine-grained marine deposits of late to post glacial origin. Prior to permafrost formation, these materials were leached by percolating precipitation, resulting in depletion of salts. Present day permafrost in these deposits is therefore very ice-rich with ice contents approaching 50-70% vol. in some areas. Such formations are of great concern in building and construction projects in Greenland, as they loose strength and bearing capacity upon thaw. It is therefore of both technical and economical interest to develop methods to precisely investigate and determine parameters such as ice-content and depth to bedrock in these areas. In terms of geophysical methods for near surface investigations, traditional methods such as Electrical Resistivity Tomography (ERT) and Refraction Seismics (RS) have generally been applied with success. The Georadar method usually fails due to very limited penetration depth in the fine-grained materials, and Electromagnetic Induction (EMI) methods are seldom applicable for quantitative interpretation due to the very high resistivities causing low induced currents and thus small secondary fields. Nevertheless, in some areas of Greenland the marine sequence was exposed relatively late, and as a result the sediments may not be completely leached of salts. In such cases, layers with pore water salinity approaching that of sea water, may be present below an upper layer of very ice rich permafrost. The saline pore water causes a freezing-point depression which results in technically unfrozen sediments at permafrost temperatures around -3 °C. Traditional ERT and VES measurements are severely affected by equivalency problems in these settings, practically prohibiting reasonable quantitative interpretation without constraining information. Such prior information may be obtained of course from boreholes, but equipment capable of drilling permafrozen sediments is generally not available in Greenland, and mobilization costs are therefore considerable thus limiting the use of geotechnical borings to larger infrastructure and construction projects. To overcome these problems, we have tested the use of shallow Transient ElectroMagnetic (TEM) measurements, to provide constraints in terms of depth to and resistivity of the conductive saline layer. We have tested such a setup at two field sites in the Ilulissat area (mid-west Greenland), one with available borehole information (site A), the second without (site C). VES and TEM soundings were collected at each site and the respective data sets subsequently inverted using a mutually constrained inversion scheme. At site A, the TEM measurements (20x20m square loop, in-loop configuration) show substantial and repeatable negative amplitude segments, and therefore it has not presently been possible to provide a quantitative interpretation for this location. Negative segments are typically a sign of Induced Polarization or cultural effects. Forward modeling based on inversion of the VES data constrained with borehole information has indicated that IP effects could indeed be the cause of the observed anomaly, although such effects are not normally expected in permafrost or saline deposits. Data from site C has shown that jointly inverting the TEM and VES measurements does provide well determined estimates for all layer parameters except the thickness of the active layer and resistivity of the bedrock. The active layer thickness may be easily probed to provide prior information on this parameter, and the bedrock resistivity is of limited interest in technical applications. Although no confirming borehole information is available at this site, these results indicate that joint or mutually constrained inversion of TEM and VES data is feasible and that this setup may provide a fast and cost effective method for establishing quantitative interpretations of permafrost structure in partly saline conditions.

Ingeman-Nielsen, Thomas; Brandt, Inooraq

2010-05-01

172

New method for quantitative analysis of multiple scelerosis using MR images  

NASA Astrophysics Data System (ADS)

A method for quantitative analysis of multiple sclerosis (MS) was presented. An automatic self-adaptive image segmentation algorithm was first employed to classify voxels in multi- spectral magnetic resonance (MR) images. The segmentation results from multi-spectral MR images were then combined to obtain reliable results. The volumes of brain tissues and cerebral spinal fluid (CSF) were finally extracted. Since it is fully automated, the results of the segmentation algorithm are completely reproducible. The repeatability of the presented method was evaluated on volunteer data sets. The variation is less than 0.2% for the intra-cranial volume, the whole brain volume, the central CSF, the white matter (WM) and the gray matter (GM). The variation of 3% for the entire CSF is mainly due to the peripheral CSF part, which has more partial volume effect and is less important than the central one. Methods for minimizing this variation are under investigation. These measurements demonstrate the potential for study on whole brain atrophy and cerebral atrophy. Feasibility studies on 14 MS patients were performed. The results are promising.

Chen, Dongqing; Huang, Wei; Christodoulou, C.; Li, Lihong; Qian, Huayuan; Krupp, Lauren; Liang, Zhengrong

2001-05-01

173

Two different hematocrit detection methods: Different methods, different results?  

PubMed Central

Background Less is known about the influence of hematocrit detection methodology on transfusion triggers. Therefore, the aim of the present study was to compare two different hematocrit-assessing methods. In a total of 50 critically ill patients hematocrit was analyzed using (1) blood gas analyzer (ABLflex 800) and (2) the central laboratory method (ADVIA® 2120) and compared. Findings Bland-Altman analysis for repeated measurements showed a good correlation with a bias of +1.39% and 2 SD of ± 3.12%. The 24%-hematocrit-group showed a correlation of r2 = 0.87. With a kappa of 0.56, 22.7% of the cases would have been transfused differently. In the-28%-hematocrit group with a similar correlation (r2 = 0.8) and a kappa of 0.58, 21% of the cases would have been transfused differently. Conclusions Despite a good agreement between the two methods used to determine hematocrit in clinical routine, the calculated difference of 1.4% might substantially influence transfusion triggers depending on the employed method.

2010-01-01

174

Evaluation of a Quantitative Fit Testing Method for N95 Filtering Facepiece Respirators  

Microsoft Academic Search

A method for performing quantitative fit tests (QNFT) with N95 filtering facepiece respirators was developed by earlier investigators. The method employs a simple clamping device to allow the penetration of submicron aerosols through N95 filter media to be measured. The measured value is subtracted from total penetration, with the assumption that the remaining penetration represents faceseal leakage. The developers have

Larry Janssen; Michael D. Luinenburg; Haskell E. Mullins; Susan G. Danisch; Thomas J. Nelson

2003-01-01

175

Screening ionisation and chromatography conditions for quantitative LC\\/MS methods  

Microsoft Academic Search

To develop an optimal quantitative LC\\/MS method with high sensitivity, high selectivity and robustness in a limited time period can be very challenging, especially for methods in which many analytes are to be quantified. In this study the relevant options are reviewed and a simple screening strategy of mass spectrometric and chromatographic conditions is presented. The strategy is divided into

Henrik Sillén; Niklas Magnell

2009-01-01

176

Numbers and Words: Combining Quantitative and Qualitative Methods in a Single Large-Scale Evaluation Study.  

ERIC Educational Resources Information Center

|Three perspectives on combining quantitative and qualitative methods in one evaluation are reviewed: mutually exclusive; separate but equal; and integrated. Ways to corroborate, elaborate, or initiate findings from the other method are illustrated, using a large-scale, three-year evaluation of regional educational service agencies. (Author/GDC)|

Rossman, Gretchen B.; Wilson, Bruce L.

1985-01-01

177

Genetic variation in flowering time induces phenological assortative mating: quantitative genetic methods applied to Brassica rapa  

Microsoft Academic Search

It has been argued from first principles that plants mate assortatively by flowering time. However, there have been very few studies of phenological assortative mating, perhaps because current methods to infer paternal phenotype are difficult to apply to natural populations. Two methods are presented to estimate the phenotypic correlation between mates—the quantitative genetic metric for assortative mating—for phenological traits. The

ARTHUR E. WEIS; TANYA M. KOSSLER

2004-01-01

178

Comparison of Six DNA Extraction Methods for Recovery of Fungal DNA as Assessed by Quantitative PCR  

Microsoft Academic Search

The detection of fungal pathogens in clinical samples by PCR requires the use of extraction methods that efficiently lyse fungal cells and recover DNA suitable for amplification. We used quantitative PCR assays to measure the recovery of DNA from two important fungal pathogens subjected to six DNA extraction methods. Aspergillus fumigatus conidia or Candida albicans yeast cells were added to

David N. Fredricks; Caitlin Smith; Amalia Meier

2005-01-01

179

Developing Investigative Entry Points: Exploring the Use of Quantitative Methods in English Education Research  

ERIC Educational Resources Information Center

|Although many research questions in English education demand the use of qualitative methods, this paper will briefly explore how English education researchers and doctoral students may use statistics and quantitative methods to inform, complement, and/or deepen their inquiries. First, the authors will provide a general overview of the survey…

McGraner, Kristin L.; Robbins, Daniel

2010-01-01

180

Detection of large deletions in the LDL receptor gene with quantitative PCR methods  

Microsoft Academic Search

BACKGROUND: Familial Hypercholesterolemia (FH) is a common genetic disease and at the molecular level most often due to mutations in the LDL receptor gene. In genetically heterogeneous populations, major structural rearrangements account for about 5% of patients with LDL receptor gene mutations. METHODS: In this study we tested the ability of two different quantitative PCR methods, i.e. Real-Time PCR and

Dorte Damgaard; Peter H Nissen; Lillian G Jensen; Gitte G Nielsen; Anette Stenderup; Mogens L Larsen; Ole Faergeman

2005-01-01

181

Comparison of Overlap Methods for Quantitatively Synthesizing Single-Subject Data  

ERIC Educational Resources Information Center

Four overlap methods for quantitatively synthesizing single-subject data were compared to visual analysts' judgments. The overlap methods were percentage of nonoverlapping data, pairwise data overlap squared, percentage of data exceeding the median, and percentage of data exceeding a median trend. Visual analysts made judgments about 160 A-B data…

Wolery, Mark; Busick, Matthew; Reichow, Brian; Barton, Erin E.

2010-01-01

182

A Simple Method for the Quantitative Determination of N-Acetyl-p-Aminophenol (APAP) in Urine  

Microsoft Academic Search

A simple method is describedfor the rapid quantitative analysisof N-acetyl-p-amino- phenol (APAP) in urine. APAP and its conjugates present in the urine following the ingestion of acetophenetidin, APAP or acetanilid, are hydrolyzed with acid to p. aminophenol. This compoundis coupledwith phenolin the presenceof hypobromiteto form an indophenol dye whose concentration is determined spectrophotometrically. Application of this method to a study

Richard M. Welch; A. H. Conney

183

Qualitative Methods Can Enrich Quantitative Research on Occupational Stress: An Example from One Occupational Group  

ERIC Educational Resources Information Center

The chapter examines the ways in which qualitative and quantitative methods support each other in research on occupational stress. Qualitative methods include eliciting from workers unconstrained descriptions of work experiences, careful first-hand observations of the workplace, and participant-observers describing "from the inside" a particular…

Schonfeld, Irvin Sam; Farrell, Edwin

2010-01-01

184

Comparison of Overlap Methods for Quantitatively Synthesizing Single-Subject Data  

ERIC Educational Resources Information Center

|Four overlap methods for quantitatively synthesizing single-subject data were compared to visual analysts' judgments. The overlap methods were percentage of nonoverlapping data, pairwise data overlap squared, percentage of data exceeding the median, and percentage of data exceeding a median trend. Visual analysts made judgments about 160 A-B data…

Wolery, Mark; Busick, Matthew; Reichow, Brian; Barton, Erin E.

2010-01-01

185

Optimization of the Weck-Cel Collection Method for Quantitation of Cytokines in Mucosal Secretions  

Microsoft Academic Search

Measurement of immune components in mucosal secretions is important for the evaluation of local immu- nity at the mucosal surfaces. The Weck-Cel ophthalmic sponge provides a method for the collection of these secretions. The sponge absorbs a relatively large volume of material, therefore allowing for quantitation of multiple immune components. Additionally, it provides a method in which the same device

LISA CENCIA ROHAN; ROBERT P. EDWARDS; LORI A. KELLY; KELLY A. COLENELLO; FREDERICK P. BOWMAN; PEGGY A. CROWLEY-NOWICK

2000-01-01

186

Estimating true human and animal host source contribution in quantitative microbial source tracking using the Monte Carlo method  

Microsoft Academic Search

Cultivation- and library-independent, quantitative PCR-based methods have become the method of choice in microbial source tracking. However, these qPCR assays are not 100% specific and sensitive for the target sequence in their respective hosts’ genome. The factors that can lead to false positive and false negative information in qPCR results are well defined. It is highly desirable to have a

Dan Wang; Sarah S. Silkie; Kara L. Nelson; Stefan Wuertz

2010-01-01

187

Comparison of Transcription-Mediated Amplification and Growth-Based Methods for the Quantitation of Enterococcus Bacteria in Environmental Waters  

Microsoft Academic Search

An assay based on transcription-mediated amplification (TMA) technology was used to quantitate Entero- coccus fecal indicator bacteria in environmental water samples. The results generated by this and two growth- based methods relative to the 104 most-probable-number or CFU-per-100-ml threshold show that the three methods are in good qualitative agreement when tested against a range of water samples taken from different

Ceri A. Morris; A. Denene Blackwood; Marek Kirs; Neil D. Buttigieg; Rhian R. Morgan; James J. Hogan; Rachel T. Noble

2008-01-01

188

RNAsnap(TM): a rapid, quantitative and inexpensive, method for isolating total RNA from bacteria  

PubMed Central

RNAsnap™ is a simple and novel method that recovers all intracellular RNA quantitatively (>99%), faster (<15?min) and less expensively (?3 cents/sample) than any of the currently available RNA isolation methods. In fact, none of the bacterial RNA isolation methods, including the commercial kits, are effective in recovering all species of intracellular RNAs (76–5700?nt) with equal efficiency, which can lead to biased results in genome-wide studies involving microarray or RNAseq analysis. The RNAsnap™ procedure yields ?60?µg of RNA from 108 Escherichia coli cells that can be used directly for northern analysis without any further purification. Based on a comparative analysis of specific transcripts ranging in size from 76 to 5700?nt, the RNAsnap™ method provided the most accurate measure of the relative amounts of the various intracellular RNAs. Furthermore, the RNAsnap™ RNA was successfully used in enzymatic reactions such as RNA ligation, reverse transcription, primer extension and reverse transcriptase–polymerase chain reaction, following sodium acetate/ethanol precipitation. The RNAsnap™ method can be used to isolate RNA from a wide range of Gram-negative and Gram-positive bacteria as well as yeast.

Stead, Mark B.; Agrawal, Ankit; Bowden, Katherine E.; Nasir, Rakia; Mohanty, Bijoy K.; Meagher, Richard B.; Kushner, Sidney R.

2012-01-01

189

Improving quantitative gas chromatography-electron ionization mass spectrometry results using a modified ion source: demonstration for a pharmaceutical application.  

PubMed

Gas chromatography-mass spectrometry is a well established analytical technique. However, mass spectrometers with electron ionization sources may suffer from signal drifts, hereby negatively influencing quantitative performance. To demonstrate this phenomenon for a real application, a static headspace-gas chromatography method in combination with electron ionization-quadrupole mass spectrometry was optimized for the determination of residual dichloromethane in coronary stent coatings. Validating the method, the quantitative performance of an original stainless steel ion source was compared to that of a modified ion source. Ion source modification included the application of a gold coating on the repeller and exit plate. Several validation aspects such as limit of detection, limit of quantification, linearity and precision were evaluated using both ion sources. It was found that, as expected, the stainless steel ion source suffered from signal drift. As a consequence, non-linearity and high RSD values for repeated analyses were obtained. An additional experiment was performed to check whether an internal standard compound would lead to better results. It was found that the signal drift patterns of the analyte and internal standard were different, consequently leading to high RSD values for the response factor. With the modified ion source however, a more stable signal was observed resulting in acceptable linearity and precision. Moreover, it was also found that sensitivity improved compared to the stainless steel ion source. Finally, the optimized method with the modified ion source was applied to determine residual dichloromethane in the coating of coronary stents. The solvent was detected but found to be below the limit of quantification. PMID:21620408

D'Autry, Ward; Wolfs, Kris; Hoogmartens, Jos; Adams, Erwin; Van Schepdael, Ann

2011-05-14

190

Clustering and training set selection methods for improving the accuracy of quantitative laser induced breakdown spectroscopy  

NASA Astrophysics Data System (ADS)

We investigated five clustering and training set selection methods to improve the accuracy of quantitative chemical analysis of geologic samples by laser induced breakdown spectroscopy (LIBS) using partial least squares (PLS) regression. The LIBS spectra were previously acquired for 195 rock slabs and 31 pressed powder geostandards under 7 Torr CO2 at a stand-off distance of 7 m at 17 mJ per pulse to simulate the operational conditions of the ChemCam LIBS instrument on the Mars Science Laboratory Curiosity rover. The clustering and training set selection methods, which do not require prior knowledge of the chemical composition of the test-set samples, are based on grouping similar spectra and selecting appropriate training spectra for the partial least squares (PLS2) model. These methods were: (1) hierarchical clustering of the full set of training spectra and selection of a subset for use in training; (2) k-means clustering of all spectra and generation of PLS2 models based on the training samples within each cluster; (3) iterative use of PLS2 to predict sample composition and k-means clustering of the predicted compositions to subdivide the groups of spectra; (4) soft independent modeling of class analogy (SIMCA) classification of spectra, and generation of PLS2 models based on the training samples within each class; (5) use of Bayesian information criteria (BIC) to determine an optimal number of clusters and generation of PLS2 models based on the training samples within each cluster. The iterative method and the k-means method using 5 clusters showed the best performance, improving the absolute quadrature root mean squared error (RMSE) by ~ 3 wt.%. The statistical significance of these improvements was ~ 85%. Our results show that although clustering methods can modestly improve results, a large and diverse training set is the most reliable way to improve the accuracy of quantitative LIBS. In particular, additional sulfate standards and specifically fabricated analog samples with Mars-like compositions may improve the accuracy of ChemCam measurements on Mars. Refinement of the iterative method, modifications of the basic k-means clustering algorithm, and classification based on specifically selected S, C and Si emission lines may also prove beneficial and merit further study.

Anderson, Ryan B.; Bell, James F., III; Wiens, Roger C.; Morris, Richard V.; Clegg, Samuel M.

2012-04-01

191

Method for measuring transformation energy and quantitative characterization of transformation-induced plasticity  

Microsoft Academic Search

A method for measuring transformation energy (E\\u000a pt) of strain-induced martensite (SIM) and quantitative characterization of transformation-induced plasticity is developed using\\u000a characteristics of the tensile curve of three metastable austenitic stainless steels, 10Cr18.5Ni8.5Mnl.9Si0.9, 19Cr17.5Ni7.4Mn2.3Si1.0,\\u000a and 10Cr16.2Ni11.8Mn1.2Si0.7. The results show that the E\\u000a pt of tested materials at ?196 C is 11.3, 14.7, and 20.1106 J\\/m3, respectively; E\\u000a pt remains constant

W. F. Zhang; Y. M. Chen; J. H. Zhu

2002-01-01

192

Quantitative in vitro to in vivo extrapolation of cell-based toxicity assay results.  

PubMed

The field of toxicology is currently undergoing a global paradigm shift to use of in vitro approaches for assessing the risks of chemicals and drugs in a more mechanistic and high throughput manner than current approaches relying primarily on in vivo testing. However, reliance on in vitro data entails a number of new challenges associated with translating the in vitro results to corresponding in vivo exposures. Physiologically based pharmacokinetic (PBPK) modeling provides an effective framework for conducting quantitative in vitro to in vivo extrapolation (QIVIVE). Their physiological structure facilitates the incorporation of in silico- and in vitro-derived chemical-specific parameters in order to predict in vivo absorption, distribution, metabolism and excretion. In particular, the combination of in silico- and in vitro parameter estimation with PBPK modeling can be used to predict the in vivo exposure conditions that would produce chemical concentrations in the target tissue equivalent to the concentrations at which effects were observed with in vitro assays of tissue/organ toxicity. This review describes the various elements of QIVIVE and highlights key aspects of the process, with an emphasis on extrapolation of in vitro metabolism data to predict in vivo clearance as the key element. Other important elements include characterization of free concentration in the toxicity assay and potential complications associated with intestinal absorption and renal clearance. Examples of successful QIVIVE approaches are described ranging from a simple steady-state approach that is suitable for a high throughput environment to more complicated approaches requiring full PBPK models. PMID:22667820

Yoon, Miyoung; Campbell, Jerry L; Andersen, Melvin E; Clewell, Harvey J

2012-06-06

193

A New Approach for the Quantitative Evaluation of the Clock Drawing Test: Preliminary Results on Subjects with Parkinson's Disease  

PubMed Central

Aims. The realization of an experimental set-up for the quantitative and objective description of drawing using optoelectronic systems, which could be used when a quantification of the realization of specific drawing tests is required. Methods. Healthy subjects, subjects with Parkinson's Disease and subjects with Parkinson's Disease and Dementia were evaluated by the Mini Mental Scale Evaluation and by a new approach to the Clock Drawing Test, based on an optoelectronic acquisition. The new protocol hereby described aims to define a parameter related to the movement kinematics in the Clock Drawing test execution. Results. The experimental set-up revealed to be valid introducing new objective measurements beside the subjective Clock Drawing Test. This paper suggests the applicability of this protocol to other fields of motor and cognitive valuation, as well as the introduction of new parameters related to the graphic movement.

De Pandis, Maria Francesca; Galli, Manuela; Vimercati, Sara; Cimolin, Veronica; De Angelis, Maria Vittoria; Albertini, Giorgio

2010-01-01

194

Quantitative analysis of collagen change between normal and cancerous thyroid tissues based on SHG method  

NASA Astrophysics Data System (ADS)

Second-harmonic generation (SHG) is proved to be a high spatial resolution, large penetration depth and non-photobleaching method. In our study, SHG method was used to investigate the normal and cancerous thyroid tissue. For SHG imaging performance, system parameters were adjusted for high-contrast images acquisition. Each x-y image was recorded in pseudo-color, which matches the wavelength range in the visible spectrum. The acquisition time for a 512×512-pixels image was 1.57 sec; each acquired image was averaged four frames to improve the signal-to-noise ratio. Our results indicated that collagen presence as determined by counting the ratio of the SHG pixels over the whole pixels for normal and cancerous thyroid tissues were 0.48+/-0.05, 0.33+/-0.06 respectively. In addition, to quantitatively assess collagen-related changes, we employed GLCM texture analysis to the SHG images. Corresponding results showed that the correlation both fell off with distance in normal and cancerous group. Calculated value of Corr50 (the distance where the correlation crossed 50% of the initial correlation) indicated significant difference. This study demonstrates that SHG method can be used as a complementary tool in thyroid histopathology.

Chen, Xiwen; Huang, Zufang; Xi, Gangqin; Chen, Yongjian; Lin, Duo; Wang, Jing; Li, Zuanfang; Sun, Liqing; Chen, Jianxin; Chen, Rong

2011-11-01

195

New Quantitative Method to Identify NPM1 Mutations in Acute Myeloid Leukaemia.  

PubMed

Somatic mutations in the NPM1 gene, which encodes for nucleophosmin, have been reported to be the most frequent genetic abnormalities found in acute myeloid leukaemia (AML). Their identification and quantification remain crucial for the patients' residual disease monitoring. We investigated a new method that could represent a novel reliable alternative to sequencing for its identification. This method was based on high-resolution melting analysis in order to detect mutated patients and on an allele-specific oligonucleotide real-time quantitative polymerase chain reaction (ASO-RQ-PCR) for the identification and quantification of the transcripts carrying NPM1 mutations (NPM1m). Few patients carrying known NPM1m enabled us to set up a table with the different primers' ?CT values, identifying a profile for each mutation type. We then analysed a series of 337 AML patients' samples for NPM1 mutational status characterization and confirmed the ASO-RQ-PCR results by direct sequencing. We identified some mutations in 86 samples, and the results were fully correlated in 100% of the 36 sequenced samples. We also detected other rare NPM1m in two samples, that we confirmed by direct sequencing. This highly specific method provides a novel quick, useful, and costless tool, easy to use in routine practice. PMID:23691328

Huet, Sarah; Jallades, Laurent; Charlot, Carole; Chabane, Kaddour; Nicolini, Franck E; Michallet, Mauricette; Magaud, Jean-Pierre; Hayette, Sandrine

2013-04-09

196

Quantitative Estimation Method for Liver Fibrosis Based on Combination of Rayleigh Distributions  

NASA Astrophysics Data System (ADS)

Since the clinical diagnosis based on ultrasonic B-mode images is dependent on the skill of the doctor, the realization of a quantitative diagnostic method using ultrasound echo signals is highly required. We have been investigating the quantitative diagnostic technique mainly on hepatic diseases. In this paper, we present a new analysis method using echo signals for the quantitative estimation of liver fibrosis. To quantitatively determine the stage of liver fibrosis, we propose a model in which the probability density function of echo amplitude is expressed as a combination of two Rayleigh distributions. These two Rayleigh distributions correspond to the echo components from the normal and diseased tissues. In addition, using this amplitude distribution model of echo amplitude, we present the estimation method to obtain the amount of fibrous tissue and stage of fibrotic degeneration of the liver from moments about mean of the echo amplitude. Basic examination using clinical images suggest that the quantitative estimation of liver fibrosis based on a combination of Rayleigh distributions is valid.

Yu Igarashi,; Hiroshi Ezuka,; Tadashi Yamaguchi,; Hiroyuki Hachiya,

2010-07-01

197

Simple but novel test method for quantitatively comparing robot mapping algorithms using SLAM and dead reckoning  

NASA Astrophysics Data System (ADS)

This article presents a comparative study between a well-known SLAM (Simultaneous Localization and Mapping) algorithm, called Gmapping, and a standard Dead-Reckoning algorithm; the study is based on experimental results of both approaches by using a commercial skid-based turning robot, P3DX. Five main base-case scenarios are conducted to evaluate and test the effectiveness of both algorithms. The results show that SLAM outperformed the Dead Reckoning in terms of map-making accuracy in all scenarios but one, since SLAM did not work well in a rapidly changing environment. Although the main conclusion about the excellence of SLAM is not surprising, the presented test method is valuable to professionals working in this area of mobile robots, as it is highly practical, and provides solid and valuable results. The novelty of this study lies in its simplicity. The simple but novel test method for quantitatively comparing robot mapping algorithms using SLAM and Dead Reckoning and some applications using autonomous robots are being patented by the authors in U.S. Patent Application Nos. 13/400,726 and 13/584,862.

Davey, Neil S.; Godil, Haris

2013-05-01

198

Quantitative Method for Shape Description of Almond Cultivars ( Prunus amygdalus Batsch)  

Microsoft Academic Search

The aim of the present work was to propose a rapid, non-invasive, and quantitative image analysis method based on elliptic\\u000a Fourier analysis (EFA) and on carpological measurements to discriminate between 18 cultivars and shape groups of almond kernels\\u000a and in-shell fruit. The shape groups were identified using two clustering techniques: a non-hierarchic method (k-means) and a hierarchical one (Ward’s method).

Francesca Antonucci; Corrado Costa; Federico Pallottino; Graziella Paglia; Valentina Rimatori; Donato De Giorgio; Paolo Menesatti

199

A quantitative study of motion estimation methods on 4D cardiac gated SPECT reconstruction  

PubMed Central

Purpose: Motion-compensated temporal processing can have a major impact on improving the image quality in gated cardiac single photon emission computed tomography (SPECT). In this work, we investigate the effect of different optical flow estimation methods for motion-compensated temporal processing in gated SPECT. In particular, we explore whether better motion estimation can substantially improve reconstructed image quality, and how the estimated motion would compare to the ideal case of known motion in terms of reconstruction. Methods: We consider the following three methods for obtaining the image motion in 4D reconstruction: (1) the Horn–Schunck optical flow equation (OFE) method, (2) a recently developed periodic OFE method, and (3) known cardiac motion derived from the NURBS-based cardiac-torso (NCAT) phantom. The periodic OFE method is used to exploit the inherent periodic nature in cardiac gated images. In this method, the optical flow in a sequence is modeled by a Fourier harmonic representation, which is then estimated from the image data. We study the impact of temporal processing on 4D reconstructions when the image motion is obtained with the different methods above. For quantitative evaluation, we use simulated imaging with multiple noise realizations from the NCAT phantom, where different patient geometry and lesion sizes are also considered. To quantify the reconstruction results, we use the following measures of reconstruction accuracy and defect detection in the myocardium: (1) overall error level in the myocardium, (2) regional accuracy of the left ventricle (LV) wall, (3) accuracy of regional time activity curves of the LV, and (4) perfusion defect detectability with a channelized Hotelling observer (CHO). In addition, we also examine the effect of noise on the distortion in the reconstructed LV wall shape by detecting its contours. As a preliminary demonstration, these methods are also tested on two sets of clinical acquisitions. Results: For the different quantitative measures considered, the periodic OFE further improved the reconstruction accuracy of the myocardium compared to OFE in 4D reconstruction; its improvement in reconstruction almost matched that of the known motion. Specifically, the overall mean-squared error in the myocardium was reduced by over 20% with periodic OFE; with noise level fixed at 10%, the regional bias on the LV was reduced from 20% (OFE) to 14% (periodic OFE), compared to 11% by the known motion. In addition, the CHO results show that there was also improvement in lesion detectability with the periodic OFE. The regional time activity curves obtained with the periodic OFE were also observed to be more consistent with the reference; in addition, the contours of the reconstructed LV wall with the periodic OFE were demonstrated to show less degree of variations among different noise realizations. Such improvements were also consistent with the results obtained from the clinical acquisitions. Conclusions: Use of improved optical flow estimation can further improve the accuracy of reconstructed images in 4D. The periodic OFE method not only can achieve improvements over the traditional OFE, but also can almost match that of the known motion in terms of the several quality measures considered.

Qi, Wenyuan; Yang, Yongyi; Niu, Xiaofeng; King, Michael A.

2012-01-01

200

Effect of platform, reference material, and quantification model on enumeration of Enterococcus by quantitative PCR methods.  

PubMed

Quantitative polymerase chain reaction (qPCR) is increasingly being used for the quantitative detection of fecal indicator bacteria in beach water. QPCR allows for same-day health warnings, and its application is being considered as an option for recreational water quality testing in the United States (USEPA, 2011. EPA-OW-2011-0466, FRL-9609-3, Notice of Availability of Draft Recreational Water Quality Criteria and Request for Scientific Views). However, transition of qPCR from a research tool to routine water quality testing requires information on how various method variations affect target enumeration. Here we compared qPCR performance and enumeration of enterococci in spiked and environmental water samples using three qPCR platforms (Applied Biosystem StepOnePlus™, the BioRad iQ™5 and the Cepheid SmartCycler(®) II), two reference materials (lyophilized cells and frozen cells on filters) and two comparative CT quantification models (?CT and ??CT). Reference materials exerted the biggest influence, consistently affecting results by approximately 0.5 log(10) unit. Platform had the smallest effect, generally exerting <0.1 log(10) unit difference in final results. Quantification model led to small differences (0.04-0.2 log(10) unit) in this study with relatively uninhibited samples, but has the potential to cause as much as 8-fold (0.9 log(10) unit) difference in potentially inhibitory samples. Our findings indicate the need for a certified and centralized source of reference materials and additional studies to assess applicability of the quantification models in analyses of PCR inhibitory samples. PMID:23123048

Cao, Yiping; Sivaganesan, Mano; Kinzelman, Julie; Blackwood, A Denene; Noble, Rachel T; Haugland, Richard A; Griffith, John F; Weisberg, Stephen B

2012-10-22

201

A method to quantitate Coomassie blue-stained proteins in cylindrical polyacrylamide gels.  

PubMed

A method for the quantitation of Coomassie blue-stained proteins in cylindrical polyacrylamide gels is described. It involves an elution of the dye with an 80% methanol solution in a sealed Pyrex tube at 100 degrees C for 3 h and a measurement of its concentration at 585 nm. Using a 6.5% polyacrylamide gel and bovine serum albumin as a protein standard, the curve of absorbance of the dye solution as a function of the amount of protein was observed to be linear up to 30-40 micrograms of protein and as little as 0.8-1.0 micrograms of protein could be measured. The validity of the method was indicated by the values obtained for the relative proportions of the human erythrocyte membrane proteins. Using this method, the color yields of several proteins varying widely with respect to their size, amino acid composition, and carbohydrate content were determined in a 6.5% polyacrylamide gel. The results showed that they were generally the same except for proteins having a high carbohydrate content which were significantly lower. PMID:4091255

Wong, P; Barbeau, A; Roses, A D

1985-11-01

202

Quantitative evaluation of linear and nonlinear methods characterizing interdependencies between brain signals  

NASA Astrophysics Data System (ADS)

Brain functional connectivity can be characterized by the temporal evolution of correlation between signals recorded from spatially-distributed regions. It is aimed at explaining how different brain areas interact within networks involved during normal (as in cognitive tasks) or pathological (as in epilepsy) situations. Numerous techniques were introduced for assessing this connectivity. Recently, some efforts were made to compare methods performances but mainly qualitatively and for a special application. In this paper, we go further and propose a comprehensive comparison of different classes of methods (linear and nonlinear regressions, phase synchronization, and generalized synchronization) based on various simulation models. For this purpose, quantitative criteria are used: in addition to mean square error under null hypothesis (independence between two signals) and mean variance computed over all values of coupling degree in each model, we provide a criterion for comparing performances. Results show that the performances of the compared methods are highly dependavxx on the hypothesis regarding the underlying model for the generation of the signals. Moreover, none of them outperforms the others in all cases and the performance hierarchy is model dependent.

Ansari-Asl, Karim; Senhadji, Lotfi; Bellanger, Jean-Jacques; Wendling, Fabrice

2006-09-01

203

Media and Communication Research Methods: An Introduction to Qualitative and Quantitative Approaches.  

ERIC Educational Resources Information Center

Examining both qualitative and quantitative approaches, this introductory text addresses media and communication research methods. Written for beginning research students at both the undergraduate and graduate levels, the book is clear, concise, and accompanied by many detailed examples. Attention-grabbing dialogue begins each chapter and gives…

Berger, Arthur Asa

204

Improved GC/MS method for quantitation of n-Alkanes in plant and fecal material  

Technology Transfer Automated Retrieval System (TEKTRAN)

A gas chromatography-mass spectrometry (GC/MS) method for the quantitation of n-alkanes (carbon backbones ranging from 21 to 36 carbon atoms) in forage and fecal samples has been developed. Automated solid-liquid extraction using elevated temperature and pressure minimized extraction time to 30 min...

205

Media and Communication Research Methods: An Introduction to Qualitative and Quantitative Approaches.  

ERIC Educational Resources Information Center

|Examining both qualitative and quantitative approaches, this introductory text addresses media and communication research methods. Written for beginning research students at both the undergraduate and graduate levels, the book is clear, concise, and accompanied by many detailed examples. Attention-grabbing dialogue begins each chapter and gives…

Berger, Arthur Asa

206

A method for accurate detection of genomic microdeletions using real-time quantitative PCR  

Microsoft Academic Search

BACKGROUND: Quantitative Polymerase Chain Reaction (qPCR) is a well-established method for quantifying levels of gene expression, but has not been routinely applied to the detection of constitutional copy number alterations of human genomic DNA. Microdeletions or microduplications of the human genome are associated with a variety of genetic disorders. Although, clinical laboratories routinely use fluorescence in situ hybridization (FISH) to

Rosanna Weksberg; Simon Hughes; Laura Moldovan; Anne S Bassett; Eva WC Chow; Jeremy A Squire

2005-01-01

207

The coexistence approach — a method for quantitative reconstructions of Tertiary terrestrial palaeoclimate data using plant fossils  

Microsoft Academic Search

The coexistence approach is introduced as a method for quantitative terrestrial palaeoclimate reconstructions in the Tertiary. It is based on the assumption that Tertiary plant taxa have similar climatic requirements to their nearest living relatives. The aim of the coexistence approach is to find for a given fossil flora and a given climate parameter the climatic interval in which all

Volker Mosbrugger; Torsten Utescher

1997-01-01

208

A simple method for quantitative diagnosis of small hive beetles, Aethina tumida, in the field  

Technology Transfer Automated Retrieval System (TEKTRAN)

Here we present a simple and fast method for quantitative diagnosis of small hive beetles (= SHB) in honeybee field colonies using corrugated plastic “diagnostic-strips”. In Australia, we evaluated its efficacy by comparing the number of lured SHB with the total number of beetles in the hives. The d...

209

Recovery of Gardnerella vaginalis from blood by the quantitative direct plating method.  

PubMed

This report describes a case of Gardnerella vaginalis sepsis in an obstetric patient whose blood cultures were negative by the conventional BACTEC system but positive by the quantitative direct plating method, which involves the direct inoculation of blood samples on chocolate agar and blood agar plates. PMID:6386869

La Scolea, L J; Dryja, D M; Dillon, W P

1984-09-01

210

Response rates with different distribution methods and reward, and reproducibility of a quantitative food frequency questionnaire  

Microsoft Academic Search

Objectives: To evaluate the use of a self-administered quantitative food frequency questionnaire (QFFQ) in a national dietary survey concerning (a) response rates with different distribution methods and reward; (b) degree of underreporting of energy intake; (c) reproducibility of the QFFQ; and (d) seasonal variation on reported intake. Design and subjects: A pilot study was performed in 1992 to test response

L Johansson; K Solvoll; S Opdahl; G-E Aa Bjørneboe; CA Drevon

1997-01-01

211

Quantitative method for relating helicopter crew task performance and mission success  

Microsoft Academic Search

A quantitative method that relates aviator performance at the cockpit task level to system performance at the mission level is described. A series of hierarchical, probabilistic conceptual models were developed that link helicopter crew task performance to mission combat success. The models were fashioned so that predictions can be made from crew task performance, through system function performance, through flight

W. B. Askren; J. E. Boyett

1990-01-01

212

COMPARISON OF TWO METHODS FOR THE QUANTITATION OF BETA-GLUCANS FROM SHIITAKE MUSHROOMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fungal polysaccharides and glucans, including lentinan from shiitakes, have been identified as promoting human health, and consequently, the sale of mushroom-based health products has increased significantly in recent years. Reliable methods for the quantitation of lentinan must be available if shi...

213

Evaluation of a Quantitative Magnetic Resonance Method for Mouse Whole Body Composition Analysis  

Microsoft Academic Search

Objective: To evaluate applicability, precision, and accuracy of a new quantitative magnetic resonance (QMR) analysis for whole body composition of conscious live mice.Research Methods and Procedures: Repeated measures of body composition were made by QMR, DXA, and classic chemical analysis of carcass using live and dead mice with different body compositions. Caloric lean and dense diets were used to produce

Frank C. Tinsley; Gersh Z. Taicher; Mark L. Heiman

2004-01-01

214

Combining Qualitative and Quantitative Methods in Information Systems Research: A Case Study  

Microsoft Academic Search

This article reports how quantitative and quaiita- tive methods were combined in a longitudinal multidisciplinary study of interreiation ships be- tween perceptions of work and a computer in- formation system. The articie describes the problems and contributions stemming from different research perspectives and methodolo- gical approaches. It illustrates four methodolo- gical points: (1) the value of combining quaiita- tive and

Bonnie Kaplan; Dennis Duchon

1988-01-01

215

Quantitative methods in marketing: The multivariate jungle revisited introduction and overview to special edition  

Microsoft Academic Search

This introductory article provides an overview of the varied and interesting contributions that follow.Certain key themes are identified which include the importance of graphical methods for communicating the information content of data and the impact of increased desktop computing power on the marketing manager's ability to work with quantitative models. Finally, a set of rules or commandments are included which

Graham J. Hooley; Michael K. Hussey

1994-01-01

216

A novel volumetric method for quantitation of titanium dioxide in cosmetics.  

PubMed

Nowadays there are many sun-protection cosmetics incorporating organic or inorganic UV filters as active ingredients. Chemically stable inorganic sunscreen agents, usually metal oxides, are widely employed in high-SPF (sun protection factor) products. Titanium dioxide is one of the most frequently used inorganic UV filters. It has been used as a pigment for a long period of cosmetic history. With the development of micronization techniques, it has become possible to incorporate titanium dioxide in sunscreen formulations without the previous whitening effect, and hence its use in cosmetics has become an important research topic. However, there are very few works related to quantitation of titanium dioxide in sunscreen products. In this research, we analyzed the amounts of titanium dioxide in sunscreen cosmetics by adapting redox titration, reduction of Ti(IV) to Ti(III), and reoxidation to Ti(IV). After calcification of other organic ingredients of cosmetics, titanium dioxide is dissolved by hot sulfuric acid. The dissolved Ti(IV) is reduced to Ti(III) by adding metallic aluminum. The reduced Ti(III) is titrated against a standard oxidizing agent, Fe(III) (ammonium iron(III) sulfate), with potassium thiocyanate as an indicator. In order to test the accuracy and applicability of the proposed method, we analyzed the amounts of titanium dioxide in four types of sunscreen cosmetics, namely cream, make-up base, foundation, and powder, after adding known amounts of titanium dioxide (1 approximately 25 w/w%). The percentages of titanium dioxide recovered in the four types of formulations were in the range between 96% and 105%. We also analyzed seven commercial cosmetic products labeled with titanium dioxide as an ingredient and compared the results with those obtained from ICP-AES (inductively coupled plasma-atomic emission spectrometry), one of the most powerful atomic analysis techniques. The results showed that the titrated amounts were well in accord with the analyzed amounts of titanium dioxide by ICP-AES. Although instrument-based analytical methods, namely ICP-MS (inductively coupled plasma-mass spectrometry) and ICP-AES, are best for the analysis of titanium, it is difficult for small cosmetic companies to install such instruments because of their high cost. It was found that the volumetric method presented here gives quantitatively accurate and reliable results with routine lab-ware and chemicals. PMID:17111072

Kim, Young So; Kim, Boo-Min; Park, Sang-Chul; Jeong, Hye-Jin; Chang, Ih Seop

217

Development of an Alu-based, Real-Time PCR Method for Quantitation of Human DNA in Forensic Samples  

Microsoft Academic Search

Running header: Human Real-Time PCR Quantitation ABSTRACT: Determining the amount of human DNA extracted from a crime scene sample is an important step in DNA profiling. The forensic community relies almost entirely upon a technique (slot blot) to quantitate human DNA that is imprecise, time consuming and labor intensive. We have previously described a method for quantitation of human DNA

Janice A. Nicklas; Eric Buel

218

Quantitative methods for analysing cumulative effects on fish migration success: a review.  

PubMed

It is often recognized, but seldom addressed, that a quantitative assessment of the cumulative effects, both additive and non-additive, of multiple stressors on fish survival would provide a more realistic representation of the factors that influence fish migration. This review presents a compilation of analytical methods applied to a well-studied fish migration, a more general review of quantitative multivariable methods, and a synthesis on how to apply new analytical techniques in fish migration studies. A compilation of adult migration papers from Fraser River sockeye salmon Oncorhynchus nerka revealed a limited number of multivariable methods being applied and the sub-optimal reliance on univariable methods for multivariable problems. The literature review of fisheries science, general biology and medicine identified a large number of alternative methods for dealing with cumulative effects, with a limited number of techniques being used in fish migration studies. An evaluation of the different methods revealed that certain classes of multivariable analyses will probably prove useful in future assessments of cumulative effects on fish migration. This overview and evaluation of quantitative methods gathered from the disparate fields should serve as a primer for anyone seeking to quantify cumulative effects on fish migration survival. PMID:22803726

Johnson, J E; Patterson, D A; Martins, E G; Cooke, S J; Hinch, S G

2012-07-01

219

Quantitative Evaluation of Experimental Results an the Heterogeneous Freezing Nucleation of Supercooled Liquids  

Microsoft Academic Search

Freezing experiments using large numbers of small drops are frequently used for the study of both homogeneous and heterogeneous nucleation of water and of other substances. For heterogeneous nucleation, the spread in the observed freezing temperatures of drops has been shown to arise from the presence of nuclei of different activities in the sample. In the past no quantitative assessment

Gabor Vali

1971-01-01

220

Bayesian data augmentation methods for the synthesis of qualitative and quantitative research findings  

PubMed Central

The possible utility of Bayesian methods for the synthesis of qualitative and quantitative research has been repeatedly suggested but insufficiently investigated. In this project, we developed and used a Bayesian method for synthesis, with the goal of identifying factors that influence adherence to HIV medication regimens. We investigated the effect of 10 factors on adherence. Recognizing that not all factors were examined in all studies, we considered standard methods for dealing with missing data and chose a Bayesian data augmentation method. We were able to summarize, rank, and compare the effects of each of the 10 factors on medication adherence. This is a promising methodological development in the synthesis of qualitative and quantitative research.

Crandell, Jamie L.; Voils, Corrine I.; Chang, YunKyung; Sandelowski, Margarete

2010-01-01

221

Reconciling incongruous qualitative and quantitative findings in mixed methods research: exemplars from research with drug using populations  

PubMed Central

Mixed methods research is increasingly being promoted in the health sciences as a way to gain more comprehensive understandings of how social processes and individual behaviours shape human health. Mixed methods research most commonly combines qualitative and quantitative data collection and analysis strategies. Often, integrating findings from multiple methods is assumed to confirm or validate the findings from one method with the findings from another, seeking convergence or agreement between methods. Cases in which findings from different methods are congruous are generally thought of as ideal, while conflicting findings may, at first glance, appear problematic. However, the latter situation provides the opportunity for a process through which apparently discordant results are reconciled, potentially leading to new emergent understandings of complex social phenomena. This paper presents three case studies drawn from the authors’ research on HIV risk among injection drug users in which mixed methods studies yielded apparently discrepant results. We use these case studies (involving injection drug users [IDUs] using a needle/syringe exchange program in Los Angeles, California, USA; IDUs seeking to purchase needle/syringes at pharmacies in Tijuana, Mexico; and young street-based IDUs in San Francisco, CA, USA) to identify challenges associated with integrating findings from mixed methods projects, summarize lessons learned, and make recommendations for how to more successfully anticipate and manage the integration of findings. Despite the challenges inherent in reconciling apparently conflicting findings from qualitative and quantitative approaches, in keeping with others who have argued in favour of integrating mixed methods findings, we contend that such an undertaking has the potential to yield benefits that emerge only through the struggle to reconcile discrepant results and may provide a sum that is greater than the individual qualitative and quantitative parts.

Wagner, Karla D.; Davidson, Peter J.; Pollini, Robin A.; Strathdee, Steffanie A.; Washburn, Rachel; Palinkas, Lawrence A.

2011-01-01

222

Method for Estimating Total Attenuation from a Spatial Map of Attenuation Slope for Quantitative Ultrasound Imaging  

PubMed Central

Estimating total ultrasound attenuation from backscatter data is essential in the field of quantitative ultrasound (QUS) because of the need to compensate for attenuation when estimating the backscatter coefficient and QUS parameters. This work uses a reference phantom method of attenuation estimation to create a spatial map of attenuation slope (AS) from backscatter radio-frequency (RF) data of three phantoms and a rat mammary adenocarcinoma tumor (MAT). The attenuation maps show changes in attenuation between different regions of the phantoms and the MAT tumor. Analyses of the attenuation maps of the phantoms suggest that the AS estimates are in good quantitative agreement with the known values for the phantoms. Furthermore, estimates of total attenuation from the attenuation maps are likewise in good quantitative agreement with known values.

Pawlicki, Alexander D.; O'Brien, William D.

2013-01-01

223

Method for estimating total attenuation from a spatial map of attenuation slope for quantitative ultrasound imaging.  

PubMed

Estimating total ultrasound attenuation from backscatter data is essential in the field of quantitative ultrasound (QUS) because of the need to compensate for attenuation when estimating the backscatter coefficient and QUS parameters. This work uses a reference phantom method of attenuation estimation to create a spatial map of attenuation slope (AS) from backscatter radio-frequency (RF) data of three phantoms and a rat mammary adenocarcinoma tumor (MAT). The attenuation maps show changes in attenuation between different regions of the phantoms and the MAT tumor. Analyses of the attenuation maps of the phantoms suggest that the AS estimates are in good quantitative agreement with the known values for the phantoms. Furthermore, estimates of total attenuation from the attenuation maps are likewise in good quantitative agreement with known values. PMID:23493614

Pawlicki, Alexander D; O'Brien, William D

2013-04-01

224

Measuring microRNAs: Comparisons of microarray and quantitative PCR measurements, and of different total RNA prep methods  

Microsoft Academic Search

BACKGROUND: Determining the expression levels of microRNAs (miRNAs) is of great interest to researchers in many areas of biology, given the significant roles these molecules play in cellular regulation. Two common methods for measuring miRNAs in a total RNA sample are microarrays and quantitative RT-PCR (qPCR). To understand the results of studies that use these two different techniques to measure

Robert A Ach; Hui Wang; Bo Curry

2008-01-01

225

COMPARISON OF TWO ORTHOGONAL LIQUID CHROMATOGRAPHIC METHODS FOR QUANTITATION OF SUGARS IN FOOD  

Microsoft Academic Search

For analysis of seven sugars in various food samples, high-performance thin-layer chromatography ultraviolet detection (HPTLC-UV) was compared with high-performance liquid chromatography evaporative light scattering detection (HPLC-ELSD). The methods were orthogonal to each other with regard to separation and detection. The benchmarking of both methods showed HPTLC as highly suited or even better, if compared to HPLC, for quantitation of sugars

Gertrud E. Morlock; Gulnar Sabir

2011-01-01

226

Progress on quantitative assessment methods of biological aerosols in the atmosphere  

NASA Astrophysics Data System (ADS)

Biological aerosol is one of the most important pollutants in the air, not only influencing public health, and air quality, but also playing an important role in climate change and both chemical and physical processing regulations in the atmosphere. Therefore, the quantification of biological aerosols in the air needs to be more accurate. This article reviews the progress on quantitative assessment methods of biological aerosols in the atmosphere as well as those related merits that each method used.

Liang, L.; He, K.; Duan, F.

2012-02-01

227

QUANTITATION OF RESISTANCE TRAINING USING THE SESSION RATING OF PERCEIVED EXERTION METHOD  

Microsoft Academic Search

Sweet, T. W., C. Foster, M. R. McGuigan, and G. Brice, Quantitation of resistance training using the session rat- ing of perceived exertion method. J. Strength Cond. Res. 18(4): 796-802. 2004.—The purpose of this study was to apply the ses- sion rating of perceived exertion (RPE) method, which is known to work with aerobic training, to resistance training. Ten men

TRAVIS W. SWEET; C ARL FOSTER; R. MCGUIGAN; GLENN BRICE

228

Research methods in sport and exercise psychology: quantitative and qualitative issues  

Microsoft Academic Search

Contemporary aspects of research methods in sport and exercise psychology are discussed in this wide-ranging review. After an introduction centred on trends in sport and exercise psychology methods, the review is organized around the major themes of quantitative and qualitative research. Our aim is to highlight areas that may be problematic or controversial (e.g. stepwise statistical procedures), underused (e.g. discriminant

Stuart J. H. Biddle; David Markland; David Gilbourne; Nikos L. D. Chatzisarantis; Andrew C. Sparkes

2001-01-01

229

Development and Validation of an HPLC Method for the Impurity and Quantitative Analysis of Etoricoxib  

Microsoft Academic Search

Etoricoxib (5?chloro?6??methyl?3[4?(methanesulfonyl)phenyl]?2,3??bipyridine) is a highly active and selective cyclo?oxygenase II inhibitor. A single, stability?indicating HPLC method has been developed and validated for both the impurity and quantitative analysis of etoricoxib. Method development incorporated the optimization of stationary phase, pH, temperature, and mobile phase composition for the resolution of thirteen process impurities and three major degradation products. Further optimization of pH

Robert Hartman; Ahmed Abrahim; Andrew Clausen; Bing Mao; Louis S. Crocker; Zhihong Ge

2003-01-01

230

New estimation method for highly sensitive quantitation of human immunodeficiency virus type 1 DNA and its application  

Microsoft Academic Search

A new estimation method for quantitation of HIV-1 DNA was established by introducing a pre-quantitation polymerase chain reaction (PCR) before conventional real-time PCR. Two alternative methods for estimating the copy number can be used: the first method utilizes the rate of ?2-microglobulin (?2M) gene amplification during the pre-quantitation PCR, and the second utilizes a calibration curve of the crossing point

Hiromi Nagai; Kaoru Wada; Takayuki Morishita; Makoto Utsumi; Yukihiro Nishiyama; Tsuguhiro Kaneda

2005-01-01

231

Quantitative planar thallium-201 stress scintigraphy: A critical evaluation of the method  

SciTech Connect

The results of quantitative analysis of planar thallium-/sup 201/ stress scintigraphy are superior to those of visual analysis. The increased sensitivity for detection of coronary artery disease is associated with maintenance of specificity. Consequently, the authors believe that quantitative analysis is the state-of-the-art for planar /sup 201/Tl stress scintigraphy. They emphasize that for reliable and reproducible results, rigorous quality control and strict adherence to a standardized imaging protocol are necessary. An important feature is clarity of display of computer data. In this experience, the most important feature for making quantitative analysis reliable and accessible for a broader user market is simultaneous display of the lower limits of normal with processed patient data. This provides a simple visual impression of the degree and extent of abnormal /sup 201/Tl distribution and kinetics relative to the lower limit of normal.

Wackers, F.J.; Fetterman, R.C.; Mattera, J.A.; Clements, J.P.

1985-01-01

232

Adhesion of dissociated mouse embryonic brain cells. A new method of quantitative evaluation.  

PubMed

The adhesion of mouse embryonic brain cells was measured in a rotating chamber. A method is proposed for quantitative evaluation of adhesion kinetics. Dissociated cells were incubated in a planparallel chamber and pictures were taken between time 0-120 min. Film negatives were evaluated by computer--controlled scanning. Ten thousand individual data area obtained from one frame and 1,000 levels of absorbency are distinguished. A method is described which allows the discrimination of area, density and the shape of adhering cells. The influence of the dissociation procedure on cellular adhesion was studied. Short trypsinisation (0.025% trypsin for 5 min) followed by sieving was most favourable for adhesion. Mechanical sieving and dissociation with EGTA (Ca2+ chelator) gave less satisfactory results. Significantly diminished adhesion was observed after prolonged trypsinisation. If cells were incubated in media lacking Ca2+, adhesion was significantly inhibited. The kinetics of adhesion follows the curve of flocculation kinetics independently of the dissociation procedure and composition of the medium. PMID:6458049

Hartman, J; Srajer, J; Fleischmannová, V; Lodin, Z

1981-01-01

233

A convenient qualitative and quantitative method to investigate RHD-RHCE hybrid genes.  

PubMed

BACKGROUND: Molecular biology techniques, such as single specific-primer polymerase chain reaction (PCR), denaturing-high performance liquid chromatography, direct sequencing, next-generation sequencing, and microarray platforms, contribute to the efficient genotyping of the human blood group RHD gene. However, some alleles remain undetermined in rare cases in DNA samples carrying two copies of the RHD gene, which challenge the identification of D-CE hybrid genes. STUDY DESIGN AND METHODS: We set up, in a single-tube format, a qualitative and quantitative assay based on multiplex PCR of short fluorescent fragments (QMPSF) to simultaneously amplify all 10 RHD exons on the one hand and all 10 RHCE exons on the other hand. RESULTS: The test proved to be useful to rapidly identify hybrid genes in hemizygous RHD samples carrying a hybrid D-CE gene and to resolve unknown genotypes by quantifying individual exons in compound heterozygous samples, but also unexpectedly helped to redefine the RHD? haplotype. While validating the test, two novel single-point variants, c.648G>C (p.L216F) and c.1048G>C (p.D350H), were found. CONCLUSION: For the first time, a QMPSF-based method is reliable to individually quantify the exons of both RH genes, including hybrid D-CE genes in compound heterozygous samples and may help to investigate samples with unknown RHD and/or RHCE status. PMID:23550903

Fichou, Yann; Le Maréchal, Cédric; Bryckaert, Laurence; Dupont, Isabelle; Jamet, Déborah; Chen, Jian-Min; Férec, Claude

2013-04-01

234

A method for obtaining randomized block designs in preclinical studies with multiple quantitative blocking variables.  

PubMed

A method is proposed for block randomization of treatments to experimental units that can accommodate both multiple quantitative blocking variables and unbalanced designs. Hierarchical clustering in conjunction with leaf-order optimization is used to block experimental units in multivariate space. The method is illustrated in the context of a diabetic mouse assay. A simulation study is presented to explore the utility of the proposed randomization method relative to that of a completely randomized approach, both in the presence and absence of covariate adjustment. An example R function is provided to illustrate the implementation of the method. PMID:20572260

Iturria, Stephen J

235

Quantitation of ergosterol content: novel method for determination of fluconazole susceptibility of Candida albicans.  

PubMed

MIC end points for the most commonly prescribed azole antifungal drug, fluconazole, can be difficult to determine because its fungistatic nature can lead to excessive "trailing" of growth during susceptibility testing by National Committee for Clinical Laboratory Standards broth macrodilution and microdilution methods. To overcome this ambiguity, and because fluconazole acts by inhibiting ergosterol biosynthesis, we developed a novel method to differentiate fluconazole-susceptible from fluconazole-resistant isolates by quantitating ergosterol production in cells grown in 0, 1, 4, 16, or 64 microg of fluconazole per ml. Ergosterol was isolated from whole yeast cells by saponification, followed by extraction of nonsaponifiable lipids with heptane. Ergosterol was identified by its unique spectrophotometric absorbance profile between 240 and 300 nm. We used this sterol quantitation method (SQM) to test 38 isolates with broth microdilution end points of /=64 microg/ml (resistant) and 10 isolates with trailing end points by the broth microdilution method. No significant differences in mean ergosterol content were observed between any of the isolates grown in the absence of fluconazole. However, 18 susceptible isolates showed a mean reduction in ergosterol content of 72% after exposure to 1 microg of fluconazole/ml, an 84% reduction after exposure to 4 microg/ml, and 95 and 100% reductions after exposure to 16 and 64 microg of fluconazole/ml, respectively. Ten SDD isolates showed mean ergosterol reductions of 38, 57, 73, and 99% after exposure to 1, 4, 16, and 64 microg of fluconazole/ml, respectively. In contrast, 10 resistant isolates showed mean reductions in ergosterol content of only 25, 38, 53, and 84% after exposure to the same concentrations of fluconazole. The MIC of fluconazole, by using the SQM, was defined as the lowest concentration of the drug which resulted in 80% or greater inhibition of overall mean ergosterol biosynthesis compared to that in the drug-free control. Of 38 isolates which gave clear end points by the broth microdilution method, the SQM MIC was within 2 dilutions of the broth microdilution MIC for 33 (87%). The SQM also discriminated between resistant and highly resistant isolates and was particularly useful for discerning the fluconazole susceptibilities of 10 additional isolates which gave equivocal end points by the broth microdilution method due to trailing growth. In contrast to the broth microdilution method, the SQM determined trailing isolates to be susceptible rather than resistant, indicating that the SQM may predict clinical outcome more accurately. The SQM may provide a means to enhance current methods of fluconazole susceptibility testing and may provide a better correlation of in vitro with in vivo results, particularly for isolates with trailing end points. PMID:10488201

Arthington-Skaggs, B A; Jradi, H; Desai, T; Morrison, C J

1999-10-01

236

Quantitative proteomics: assessing the spectrum of in-gel protein detection methods  

PubMed Central

Proteomics research relies heavily on visualization methods for detection of proteins separated by polyacrylamide gel electrophoresis. Commonly used staining approaches involve colorimetric dyes such as Coomassie Brilliant Blue, fluorescent dyes including Sypro Ruby, newly developed reactive fluorophores, as well as a plethora of others. The most desired characteristic in selecting one stain over another is sensitivity, but this is far from the only important parameter. This review evaluates protein detection methods in terms of their quantitative attributes, including limit of detection (i.e., sensitivity), linear dynamic range, inter-protein variability, capacity for spot detection after 2D gel electrophoresis, and compatibility with subsequent mass spectrometric analyses. Unfortunately, many of these quantitative criteria are not routinely or consistently addressed by most of the studies published to date. We would urge more rigorous routine characterization of stains and detection methodologies as a critical approach to systematically improving these critically important tools for quantitative proteomics. In addition, substantial improvements in detection technology, particularly over the last decade or so, emphasize the need to consider renewed characterization of existing stains; the quantitative stains we need, or at least the chemistries required for their future development, may well already exist.

Gauci, Victoria J.; Wright, Elise P.

2010-01-01

237

A Quantitative Method for Assessment of Prescribing Patterns Using Electronic Health Records  

PubMed Central

Background Most available quality indicators for hospitals are represented by simple ratios or proportions, and are limited to specific events. A generalized method that can be applied to diverse clinical events has not been developed. The aim of this study was to develop a simple method of evaluating physicians' prescription patterns for diverse events and their level of awareness of clinical practice guidelines. Methods and Findings We developed a quantitative method called Prescription pattern Around Clinical Event (PACE), which is applicable to electronic health records (EHRs). Three discrete prescription patterns (intervention, maintenance, and discontinuation) were determined based on the prescription change index (PCI), which was calculated by means of the increase or decrease in the prescription rate after a clinical event. Hyperkalemia and Clostridium difficile-associated diarrhea (CDAD) were used as example cases. We calculated the PCIs of 10 drugs related to hyperkalemia, categorized them into prescription patterns, and then compared the resulting prescription patterns with the known standards for hyperkalemia treatment. The hyperkalemia knowledge of physicians was estimated using a questionnaire and compared to the prescription pattern. Prescriptions for CDAD were also determined and compared to clinical knowledge. Clinical data of 1698, 348, and 1288 patients were collected from EHR data. The physicians prescribing behaviors for hyperkalemia and CDAD were concordant with the standard knowledge. Prescription patterns were well correlated with individual physicians' knowledge of hyperkalemia (??=?0.714). Prescribing behaviors according to event severity or clinical condition were plotted as a simple summary graph. Conclusion The algorithm successfully assessed the prescribing patterns from the EHR data. The prescription patterns were well correlated with physicians' knowledge. We expect that this algorithm will enable quantification of prescribers' adherence to clinical guidelines and be used to facilitate improved prescribing practices.

Schuemie, Martijn J.; Park, Man Young; Kim, Ju Han; Park, Rae Woong

2013-01-01

238

Quantitative Assessment of Bactericidal Activities of ?-Lactam Antibiotics by Agar Plate Method  

PubMed Central

Quantitative bactericidal activities of ?-lactam antibiotics were determined by the agar plate method. Broth cultures, of which the colony-forming units were counted before the study, were inoculated on antibiotic-containing agar plates, utilizing a 10?3, 10?2, or 10?1 dilution or undiluted culture plated with each 0.001-ml calibrated loop. These plates were incubated at 37°C overnight, and the minimal drug concentration at which no bacterial growth was observed on the plates was defined as minimal inhibitory concentration. After this procedure, the agar surface was treated with ?-lactamase spray to inactivate the antibiotic. These plates were incubated again at 37°C overnight. The minimal drug concentration at which no evidence of bacterial growth was visible on the plates (resulting in a 100% kill) was defined as minimal bactericidal concentration. The lowest concentration which reduced the number of colony-forming units to 1/1,000 that in the original inoculum (resulting in a 99.9% kill) was defined as minimal lethal concentration. When compared for Escherichia coli, Klebsiella pneumoniae, Enterobacter sp., Serratia marcescens, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, alpha-hemolytic streptococcus (non-enterococcal), beta-hemolytic streptococcus, and enterococcus, the minimal bactericidal concentrations were generally several fold higher than the minimal inhibitory concentrations. Minimal lethal concentrations were virtually the same as minimal inhibitory concentrations for gram-negative strains; however, for some gram-positive strains, minimal lethal concentrations were higher than minimal inhibitory concentrations.

Masuda, Gohta; Tomioka, Susumu

1978-01-01

239

Qualitative and quantitative event-specific PCR detection methods for oxy-235 canola based on the 3' integration flanking sequence.  

PubMed

As more genetically modified plant events are approved for commercialization worldwide, the event-specific PCR method has become the key method for genetically modified organism (GMO) identification and quantification. This study reveals the 3' flanking sequence of the exogenous integration of Oxy-235 canola employing thermal asymmetric interlaced PCR (TAIL-PCR). On the basis of the revealed 3' flanking sequence, PCR primers and TaqMan probe were designed and qualitative and quantitative PCR assays were established for Oxy-235 canola. The specificity and limits of detection (LOD) and quantification (LOQ) of these two PCR assays were validated to as low as 0.1% for the relative LOD of qualitative PCR assay; the absolute LOD and LOQ were low to 10 and 20 copies of canola genomic DNA in quantitative PCR assay, respectively. Furthermore, ideal quantified results were obtained in the practical canola sample detection. All of the results indicate that the developed qualitative and quantitative PCR methods based on the revealed 3' integration flanking sequence are suitable for GM canola Oxy-235 identification and quantification. PMID:18298073

Yang, Litao; Guo, Jinchao; Zhang, Haibo; Liu, Jia; Zhang, Dabing

2008-02-26

240

Comparison of quantitative results of drugs in human hair by GC/MS.  

PubMed

Until the first determination of opiates in human hair by GC/MS in 1985, radioimmunological results of hair examinations met with opposition. Since then, further GC/MS methods have been developed that have led not only to considerably increased sensitivity, but can also be used in hair analysis for screening purposes and can detect substances for which RIA kits are not available. In the present study different extraction methods were used along with two GC/MS processes which back-up each other. These methods include the enzymatic dissolution of the hair, incubation with a buffer solution followed by a solid-phase extraction and incubation with methanol without a further extraction. The GC/MS examination for heroin, cocaine, hashish and selected pharmaceuticals was carried out after derivatization with pentafluoropropionic acid anhydride or pentafluoro-1-propanol. Because of the higher sensitivity and versatility of GC/MS, two GC/MS processes were used to confirm each other instead of backing-up radioimmunological measurements with GC/MS. PMID:8138222

Sachs, H; Raff, I

1993-12-01

241

Quantitative ultrasound of cortical bone in the femoral neck predicts femur strength: results of a pilot study.  

PubMed

A significant risk of femoral neck (FN) fracture exists for men and women with an areal bone mineral density (aBMD) higher than the osteoporotic range, as measured with dual-energy X-ray absorptiometry (DXA). Separately measuring the cortical and trabecular FN compartments and combining the results would likely be a critical aspect of enhancing the diagnostic capabilities of a new technique. Because the cortical shell determines a large part of FN strength a novel quantitative ultrasound (QUS) technique that probes the FN cortical compartment was implemented. The sensitivity of the method to variations of FN cortical properties and FN strength was tested. Nine femurs (women, mean age 83 years) were subjected to QUS to measure the through transmission time-of-flight (TOF) at the FN and mechanical tests to assess strength. Quantitative computed tomography (QCT) scans were performed to enable analysis of the dependence of TOF on bone parameters. DXA was also performed for reference. An ultrasound wave propagating circumferentially in the cortical shell was measured in all specimens. Its TOF was not influenced by the properties of the trabecular compartment. Averaged TOF for nine FN measurement positions/orientations was significantly correlated to strength (R2 ?=?0.79) and FN cortical QCT variables: total BMD (R(2) ?=?0.54); regional BMD in the inferoanterior (R2 ?=?0.90) and superoanterior (R2 ?=?0.57) quadrants; and moment of inertia (R2 ?=?0.71). The results of this study demonstrate that QUS can perform a targeted measurement of the FN cortical compartment. Because the method involves mechanical guided waves, the QUS variable is related to the geometric and material properties of the cortical shell (cortical thickness, tissue elasticity, and porosity). This work opens the way to a multimodal QUS assessment of the proximal femur, combining our approach targeting the cortical shell with the existing modality sensitive to the trabecular compartment. In vivo feasibility of our approach has to be confirmed with experimental data in patients. PMID:22915370

Grimal, Quentin; Grondin, Julien; Guérard, Sandra; Barkmann, Reinhard; Engelke, Klaus; Glüer, Claus-C; Laugier, Pascal

2013-02-01

242

Multi-Window Classical Least Squares Multivariate Calibration Methods for Quantitative ICP-AES Analyses  

SciTech Connect

The advent of inductively coupled plasma-atomic emission spectrometers (ICP-AES) equipped with charge-coupled-device (CCD) detector arrays allows the application of multivariate calibration methods to the quantitative analysis of spectral data. We have applied classical least squares (CLS) methods to the analysis of a variety of samples containing up to 12 elements plus an internal standard. The elements included in the calibration models were Ag, Al, As, Au, Cd, Cr, Cu, Fe, Ni, Pb, Pd, and Se. By performing the CLS analysis separately in each of 46 spectral windows and by pooling the CLS concentration results for each element in all windows in a statistically efficient manner, we have been able to significantly improve the accuracy and precision of the ICP-AES analyses relative to the univariate and single-window multivariate methods supplied with the spectrometer. This new multi-window CLS (MWCLS) approach simplifies the analyses by providing a single concentration determination for each element from all spectral windows. Thus, the analyst does not have to perform the tedious task of reviewing the results from each window in an attempt to decide the correct value among discrepant analyses in one or more windows for each element. Furthermore, it is not necessary to construct a spectral correction model for each window prior to calibration and analysis: When one or more interfering elements was present, the new MWCLS method was able to reduce prediction errors for a selected analyte by more than 2 orders of magnitude compared to the worst case single-window multivariate and univariate predictions. The MWCLS detection limits in the presence of multiple interferences are 15 rig/g (i.e., 15 ppb) or better for each element. In addition, errors with the new method are only slightly inflated when only a single target element is included in the calibration (i.e., knowledge of all other elements is excluded during calibration). The MWCLS method is found to be vastly superior to partial least squares (PLS) in this case of limited numbers of calibration samples.

CHAMBERS,WILLIAM B.; HAALAND,DAVID M.; KEENAN,MICHAEL R.; MELGAARD,DAVID K.

1999-10-01

243

A method for operative quantitative interpretation of multispectral images of biological tissues  

NASA Astrophysics Data System (ADS)

A method for operative retrieval of spatial distributions of biophysical parameters of a biological tissue by using a multispectral image of it has been developed. The method is based on multiple regressions between linearly independent components of the diffuse reflection spectrum of the tissue and unknown parameters. Possibilities of the method are illustrated by an example of determining biophysical parameters of the skin (concentrations of melanin, hemoglobin and bilirubin, blood oxygenation, and scattering coefficient of the tissue). Examples of quantitative interpretation of the experimental data are presented.

Lisenko, S. A.; Kugeiko, M. M.

2013-10-01

244

Reliability of a semi-quantitative method for dermal exposure assessment (DREAM).  

PubMed

Valid and reliable semi-quantitative dermal exposure assessment methods for epidemiological research and for occupational hygiene practice, applicable for different chemical agents, are practically nonexistent. The aim of this study was to assess the reliability of a recently developed semi-quantitative dermal exposure assessment method (DREAM) by (i) studying inter-observer agreement, (ii) assessing the effect of individual observers on dermal exposure estimates for different tasks, and (iii) comparing inter-observer agreement for ranking of body parts according to their exposure level. Four studies were performed in which a total of 29 observers (mainly occupational hygienists) were asked to fill in DREAM while performing side-by-side observations for different tasks, comprising dermal exposures to liquids, solids, and vapors. Intra-class correlation coefficients ranged from 0.68 to 0.87 for total dermal exposure estimates, indicating good to excellent inter-observer agreement. The effects of individual observers on task estimates were estimated using a linear mixed effect model with logged DREAM estimates as explanatory variable; "task", "company/department", and the interaction of "task" and "company/department" as fixed effects; and "observer" as a random effect. Geometric mean (GM) dermal exposure estimates for different tasks were estimated by taking the exponent of the predicted betas for the tasks. By taking the exponent of the predicted observer's intercept (exp(omega i)), a multiplier (M(O)) was estimated for each observer. The effects of individual observers on task estimates were relatively small, as the maximum predicted mean observers' multiplier was only a factor 2, while predicted GMs of dermal exposure estimates for tasks ranged from 0 to 1226, and none of the predicted individual observers' multipliers differed significantly from 1 (t-test alpha = 0.05). Inter-observer agreement for ranking of dermal exposure of nine body parts was moderate to good, as median values of Spearman correlation coefficients for pairs of observers ranged from 0.29 to 0.93. DREAM provides reproducible results for a broad range of tasks with dermal exposures to liquids, solids, as well as vapors. DREAM appears to offer a useful advance for estimations of dermal exposure both for epidemiological research and for occupational hygiene practice. PMID:15069425

van Wendel de Joode, Berna; van Hemmen, Joop J; Meijster, Tim; Major, Vicky; London, Leslie; Kromhout, Hans

2005-01-01

245

Application of quantitative 1H-NMR method to determination of paeoniflorin in Paeoniae radix.  

PubMed

A quantitative (1)H-NMR method (qHNMR) was used to measure paeoniflorin content in Paeoniae radix (dried root of Paeonia lactiflora), of which paeoniflorin is a major component. The purity of paeoniflorin was calculated from the ratio of the intensity of the H-9 signal at ? 5.78 ppm of paeoniflorin to that of a hexamethyldisilane (HMD) signal at 0 ppm. The concentration of HMD was corrected with SI traceability by using bisphenol A of certified reference material (CRM) grade. The paeoniflorin content in 2 separate samples of Paeoniae radix was determined by qHNMR and was found to be 2.15 and 2.45%. We demonstrated that this method is useful for quantitative analysis of crude drugs. PMID:23081682

Tanaka, Rie; Yamazaki, Marina; Hasada, Keiko; Nagatsu, Akito

2012-10-19

246

?erenkov radiation imaging as a method for quantitative measurements of beta particles in a microfluidic chip  

Microsoft Academic Search

This work proposes a novel method for quantitative imaging of radioactivity on microfluidic chips by using visible light emission from ?erenkov radiation. ?erenkov radiation is generated when charged particles travel through an optically transparent material with a velocity greater than that of light in that material. It has been observed at UCLA that microfluidic chips used for 18F-related radio-synthesis studies

J. S. Cho; A. Douraghy; S. Olma; K. Liu; Y. C. Chen; C. K. Shen; R. W. Silverman; R. M. van Dam; Arion F. Chatziioannou

2008-01-01

247

A quantitative method to detect fucoidan in human plasma using a novel antibody  

Microsoft Academic Search

SUMMARY We have developed an antibody-based method to assess plasma uptake of a proprietary Undaria-derived fucoidan galactofucan sulfate (GFS TM ) after oral ingestion by human volunteers. Fucoidans have high-molecular-weights but exert biological effects in experimental animals after oral intake. By using a novel antibody raised against sulfated polysaccharides, we carried out a competitive ELISA to quantitate GFS in plasma

M. R. Irhimeh; J. H. Fitton; R. M. Lowenthal; P. Kongtawelert

2005-01-01

248

Comparison of Fluorometric Detection Methods for Quantitative Polymerase Chain Reaction (PCR)  

Microsoft Academic Search

In this study, we compared the sensitivity of two different detection methods for quantitative polymerase chain reaction (PCR). Various amounts of a 75 mer single?stranded deoxyribonucleic acid (DNA) fragment, which can be used as a DNA label for the immuno?PCR (iPCR) assays, were amplified by PCR. The amount of amplified DNA fragments was determined by the fluorescence (FL) of SYBR

Susan Schiavo; Norman H. L. Chiu; Ira S. Krull

2005-01-01

249

Quantitative methods for genome-scale analysis of in situ hybridization and correlation with microarray data  

PubMed Central

With the emergence of genome-wide colorimetric in situ hybridization (ISH) data sets such as the Allen Brain Atlas, it is important to understand the relationship between this gene expression modality and those derived from more quantitative based technologies. This study introduces a novel method for standardized relative quantification of colorimetric ISH signal that enables a large-scale cross-platform expression level comparison of ISH with two publicly available microarray brain data sources.

Lee, Chang-Kyu; Sunkin, Susan M; Kuan, Chihchau; Thompson, Carol L; Pathak, Sayan; Ng, Lydia; Lau, Chris; Fischer, Shanna; Mortrud, Marty; Slaughterbeck, Cliff; Jones, Allan; Lein, Ed; Hawrylycz, Michael

2008-01-01

250

A method for the quantitative determination of individual oils in a blend  

Microsoft Academic Search

A matrix inversion method, based on the data obtained by GLC analysis of fatty acids, sterols, 4-methylsterols, triterpene\\u000a alcohols, tocopherols and squalene, was applied to quantitatively determine ingredients of vegetable oil blends. Identification\\u000a of individual oils in mixtures was achieved by comparison of a set of data derived on the basis of the level of certain characteristic\\u000a components in each

A. M. Abu-Hadeed; Ahmed R. Kotb

1988-01-01

251

Methods and considerations for quantitative Western blotting using SuperSignal ® Chemiluminescent Substrates  

Microsoft Academic Search

Classical Western blotting is considered a qualitative method; however, it can be used for quantitative analysis of proteins pro- vided that specific controls are included. Using SuperSignal ® West Dura Chemiluminescent Substrate we qualitatively and quan- titatively detected changes in the regulation of IkB? and p53 in A431 cells treated with EGF (and doxorubicin or cisplatin) by comparing to a

Mahesh Mathrubutham; Krishna Vattem

252

A new semiautomatic method for quantitative static and dynamic bone histology  

Microsoft Academic Search

Summary  A new semiautomatic technique combining advantages of the manual and fully automatic methods is described for obtaining quantitative\\u000a static and dynamic histologic data of bone. The hardware consists of a photomicroscope, digitizing platen, digitizer, plotter\\/printer,\\u000a floppy disc drive, and computer. The microscope is equipped with a drawing tube through which the image of the digitizing\\u000a platen is projected over the

Hartmut H. Malluche; David Sherman; Wolfgang Meyer; Shaul G. Massry

1982-01-01

253

Simultaneous Quantitative Determination Method for Sphingolipid Metabolites by Liquid Chromatography\\/Ionspray Ionization Tandem Mass Spectrometry  

Microsoft Academic Search

Sphingolipid metabolites ceramide, sphingomyelin, sphingosine, psycosine, sphingosylphosphorylcholine, and dimethylsphingosine were separated and simultaneously quantitated by liquid chromatography\\/ionspray ionization tandem mass spectrometry (LC\\/MS\\/MS). The use of glassware throughout minimized losses due to adsorption and the pretreatment of this method consisted of simple liquid–liquid extraction procedure with a mixture of chloroform and methanol. After separation on a short C18silica column eluted in

Nariyasu Mano; Yoshiya Oda; Koji Yamada; Naoki Asakawa; Kouichi Katayama

1997-01-01

254

Validation of a Quantitative Magnetic Resonance Method for Measuring Human Body Composition  

Microsoft Academic Search

Objective:To evaluate a novel quantitative magnetic resonance (QMR) methodology (EchoMRI-AH, Echo Medical Systems) for measurement of whole-body fat and lean mass in humans.Methods and Procedures:We have studied (i) the in vitro accuracy and precision by measuring 18 kg Canola oil with and without 9 kg water (ii) the accuracy and precision of measures of simulated fat mass changes in human

Antonella Napolitano; Sam R. Miller; Peter R. Murgatroyd; W. Andrew Coward; Antony Wright; Nick Finer; Tjerk W. De Bruin; Edward T. Bullmore; Derek J. Nunez

2008-01-01

255

EFFECTIVE REMOVAL METHOD OF ILLEGAL PARKING BICYCLES BASED ON THE QUANTITATIVE CHANGE AFTER REMOVAL  

NASA Astrophysics Data System (ADS)

This study aims to find an effective removal method of illegal parking bicycles based on the analysis on the numerical change of illegal bicycles. And then, we built the time and space quantitative distribution model of illegal parking bicycles after removal, considering the logistic increase of illegal parking bicycles, several behaviors concerning of direct return or indirect return to the original parking place and avoidance of the original parking place, based on the investigation of real condition of illegal bicycle parking at TENJIN area in FUKUOKA city. Moreover, we built the simulation model including above-mentioned model, and calculated the number of illegal parking bicycles when we change the removal frequency and the number of removal at one time. The next interesting four results were obtained. (1) Recovery speed from removal the illegal parking bicycles differs by each zone. (2) Thorough removal is effective to keep the number of illegal parking bicycles lower level. (3) Removal at one zone causes the increase of bicycles at other zones where the level of illegal parking is lower. (4) The relationship between effects and costs of removing the illegal parking bicycles was clarified.

Toi, Satoshi; Kajita, Yoshitaka; Nishikawa, Shuichirou

256

[Quantitative analysis of protein concentration by absorption peak integration method of UV spectroscopy--taking alkaline phosphatase as an example].  

PubMed

Adsorption of alkaline phosphatase (APase) on minerals (goethite, montmorillonite) and sediments from Taihu Lake was studied. However, the concentration of alkaline phosphatase in the supernatant cannot be analyzed by the adsorption at 280 nm due to that the UV spectroscopy was changed. Quantitative analysis of alkaline phosphatase in the supernatant by the absorption peak (252-305 nm) integration method of UV spectroscopy was developed. This method determined the concentrations of alkaline phosphatase well. Compared to the results of Bradford, the absorption peak integration method can determine the concentrations of supernatant fast, conveniently, and accurately. This method can also be applied to other protein solution analysis and similar experiments. The drawbacks of traditional single wavelength method (280nm) were overcome to some extent based on the method of absorption peak integration. PMID:24059187

Zhu, Yuan-Rong; Wu, Feng-Chang; Lin, Ying

2013-07-01

257

Test Characteristics of Urinary Biomarkers Depend on Quantitation Method in Acute Kidney Injury  

PubMed Central

The concentration of urine influences the concentration of urinary biomarkers of AKI. Whether normalization to urinary creatinine concentration, as commonly performed to quantitate albuminuria, is the best method to account for variations in urinary biomarker concentration among patients in the intensive care unit is unknown. Here, we compared the diagnostic and prognostic performance of three methods of biomarker quantitation: absolute concentration, biomarker normalized to urinary creatinine concentration, and biomarker excretion rate. We measured urinary concentrations of alkaline phosphatase, ?-glutamyl transpeptidase, cystatin C, neutrophil gelatinase–associated lipocalin, kidney injury molecule–1, and IL-18 in 528 patients on admission and after 12 and 24 hours. Absolute concentration best diagnosed AKI on admission, but normalized concentrations best predicted death, dialysis, or subsequent development of AKI. Excretion rate on admission did not diagnose or predict outcomes better than either absolute or normalized concentration. Estimated 24-hour biomarker excretion associated with AKI severity, and for neutrophil gelatinase–associated lipocalin and cystatin C, with poorer survival. In summary, normalization to urinary creatinine concentration improves the prediction of incipient AKI and outcome but provides no advantage in diagnosing established AKI. The ideal method for quantitating biomarkers of urinary AKI depends on the outcome of interest.

Md Ralib, Azrina; Pickering, John W.; Shaw, Geoffrey M.; Devarajan, Prasad; Edelstein, Charles L.; Bonventre, Joseph V.

2012-01-01

258

Quantitative HPLC-UV method for the determination of firocoxib from horse and dog plasma.  

PubMed

A sensitive reversed-phase HPLC-UV method was developed for the determination of firocoxib, a novel and highly selective COX-2 inhibitor, in plasma. A 1.0 mL dog or horse plasma sample is mixed with water and passed through a hydrophobic-lipophilic copolymer solid-phase extraction column to isolate firocoxib. Quantitation is based on an external standard curve. The method has a validated limit of quantitation of 25 ng/mL and a limit of detection of 10 ng/mL. The validated upper limit of quantitation was 2500 ng/mL for horses and 10,000 ng/mL for dogs. The average recoveries ranged from 88-93% for horse plasma and 96-103% for dog plasma. The coefficient of variation in all cases was less than 10%. This method is suitable for the analysis of clinical samples from pharmacokinetic and bioequivalence studies and drug monitoring. PMID:17537684

Kvaternick, Valerie; Malinski, Thomas; Wortmann, Jill; Fischer, James

2007-05-10

259

Task 4.4 - development of supercritical fluid extraction methods for the quantitation of sulfur forms in coal  

SciTech Connect

Development of advanced fuel forms depends on having reliable quantitative methods for their analysis. Determination of the true chemical forms of sulfur in coal is necessary to develop more effective methods to reduce sulfur content. Past work at the Energy & Environmental Research Center (EERC) indicates that sulfur chemistry has broad implications in combustion, gasification, pyrolysis, liquefaction, and coal-cleaning processes. Current analytical methods are inadequate for accurately measuring sulfur forms in coal. This task was concerned with developing methods to quantitate and identify major sulfur forms in coal based on direct measurement (as opposed to present techniques based on indirect measurement and difference values). The focus was on the forms that were least understood and for which the analytical methods have been the poorest, i.e., organic and elemental sulfur. Improved measurement techniques for sulfatic and pyritic sulfur also need to be developed. A secondary goal was to understand the interconversion of sulfur forms in coal during thermal processing. EERC has developed the first reliable analytical method for extracting and quantitating elemental sulfur from coal (1). This method has demonstrated that elemental sulfur can account for very little or as much as one-third of the so-called organic sulfur fraction. This method has disproved the generally accepted idea that elemental sulfur is associated with the organic fraction. A paper reporting the results obtained on this subject entitled {open_quote}Determination of Elemental Sulfur in Coal by Supercritical Fluid Extraction and Gas Chromatography with Atomic Emission Detection{close_quote} was published in Fuel (A).

Timpe, R.C.

1995-04-01

260

The Use of Quantitative and Qualitative Methods in the Analysis of Academic Achievement among Undergraduates in Jamaica  

ERIC Educational Resources Information Center

This paper describes a study which uses quantitative and qualitative methods in determining the relationship between academic, institutional and psychological variables and degree performance for a sample of Jamaican undergraduate students. Quantitative methods, traditionally associated with the positivist paradigm, and involving the counting and…

McLaren, Ingrid Ann Marie

2012-01-01

261

Generalized Finite Element Methods: Main Ideas, Results, and Perspective  

Microsoft Academic Search

This paper is an overview of the main ideas of the Generalized Finite Element Method (GFEM). We present the basic results, experiences with, and potentials of this method. The GFEM is a generalization of the classical Finite Element Method — in its h;p, and h-p versions — as well as of the various forms of meshless methods used in engineering.

Ivo Babuska; Uday Banerjee; John E. Osborn

2004-01-01

262

Post-reconstruction non-local means filtering methods using CT side information for quantitative SPECT  

NASA Astrophysics Data System (ADS)

Quantitative SPECT techniques are important for many applications including internal emitter therapy dosimetry where accurate estimation of total target activity and activity distribution within targets are both potentially important for dose–response evaluations. We investigated non-local means (NLM) post-reconstruction filtering for accurate I-131 SPECT estimation of both total target activity and the 3D activity distribution. We first investigated activity estimation versus number of ordered-subsets expectation–maximization (OSEM) iterations. We performed simulations using the XCAT phantom with tumors containing a uniform and a non-uniform activity distribution, and measured the recovery coefficient (RC) and the root mean squared error (RMSE) to quantify total target activity and activity distribution, respectively. We observed that using more OSEM iterations is essential for accurate estimation of RC, but may or may not improve RMSE. We then investigated various post-reconstruction filtering methods to suppress noise at high iteration while preserving image details so that both RC and RMSE can be improved. Recently, NLM filtering methods have shown promising results for noise reduction. Moreover, NLM methods using high-quality side information can improve image quality further. We investigated several NLM methods with and without CT side information for I-131 SPECT imaging and compared them to conventional Gaussian filtering and to unfiltered methods. We studied four different ways of incorporating CT information in the NLM methods: two known (NLM CT-B and NLM CT-M) and two newly considered (NLM CT-S and NLM CT-H). We also evaluated the robustness of NLM filtering using CT information to erroneous CT. NLM CT-S and NLM CT-H yielded comparable RC values to unfiltered images while substantially reducing RMSE. NLM CT-S achieved ?2.7 to 2.6% increase of RC compared to no filtering and NLM CT-H yielded up to 6% decrease in RC while other methods yielded lower RCs than them: Gaussian filtering (up to 11.8% decrease in RC), NLM method without CT (up to 9.5% decrease in RC), and NLM CT-M and NLM CT-B (up to 19.4% decrease in RC). NLM CT-S and NLM CT-H achieved 8.2 to 33.9% and ?0.9 to 36% decreased RMSE on tumors compared to no filtering respectively while other methods yielded less reduced or increased RMSE: Gaussian filtering (up to 7.9% increase in RMSE), NLM method without CT (up to 18.3% increase in RMSE), and NLM CT-M and NLM CT-B (up to 31.5% increase in RMSE). NLM CT-S and NLM CT-H also yielded images with tumor shapes that better-matched the true shapes than other methods. All NLM methods using CT information were robust to small misregistration between SPECT and CT, but NLM CT-S and NLM CT-H were more sensitive than NLM CT-M and NLM CT-B to missing CT information.

Chun, Se Young; Fessler, Jeffrey A.; Dewaraja, Yuni K.

2013-09-01

263

Post-reconstruction non-local means filtering methods using CT side information for quantitative SPECT.  

PubMed

Quantitative SPECT techniques are important for many applications including internal emitter therapy dosimetry where accurate estimation of total target activity and activity distribution within targets are both potentially important for dose–response evaluations. We investigated non-local means (NLM) post-reconstruction filtering for accurate I-131 SPECT estimation of both total target activity and the 3D activity distribution. We first investigated activity estimation versus number of ordered-subsets expectation–maximization (OSEM) iterations. We performed simulations using the XCAT phantom with tumors containing a uniform and a non-uniform activity distribution, and measured the recovery coefficient (RC) and the root mean squared error (RMSE) to quantify total target activity and activity distribution, respectively. We observed that using more OSEM iterations is essential for accurate estimation of RC, but may or may not improve RMSE. We then investigated various post-reconstruction filtering methods to suppress noise at high iteration while preserving image details so that both RC and RMSE can be improved. Recently, NLM filtering methods have shown promising results for noise reduction. Moreover, NLM methods using high-quality side information can improve image quality further. We investigated several NLM methods with and without CT side information for I-131 SPECT imaging and compared them to conventional Gaussian filtering and to unfiltered methods. We studied four different ways of incorporating CT information in the NLM methods: two known (NLM CT-B and NLM CT-M) and two newly considered (NLM CT-S and NLM CT-H). We also evaluated the robustness of NLM filtering using CT information to erroneous CT. NLM CT-S and NLM CT-H yielded comparable RC values to unfiltered images while substantially reducing RMSE. NLM CT-S achieved ?2.7 to 2.6% increase of RC compared to no filtering and NLM CT-H yielded up to 6% decrease in RC while other methods yielded lower RCs than them: Gaussian filtering (up to 11.8% decrease in RC), NLM method without CT (up to 9.5% decrease in RC), and NLM CT-M and NLM CT-B (up to 19.4% decrease in RC). NLM CT-S and NLM CT-H achieved 8.2 to 33.9% and ?0.9 to 36% decreased RMSE on tumors compared to no filtering respectively while other methods yielded less reduced or increased RMSE: Gaussian filtering (up to 7.9% increase in RMSE), NLM method without CT (up to 18.3% increase in RMSE), and NLM CT-M and NLM CT-B (up to 31.5% increase in RMSE). NLM CT-S and NLM CT-H also yielded images with tumor shapes that better-matched the true shapes than other methods. All NLM methods using CT information were robust to small misregistration between SPECT and CT, but NLM CT-S and NLM CT-H were more sensitive than NLM CT-M and NLM CT-B to missing CT information. PMID:23956327

Chun, Se Young; Fessler, Jeffrey A; Dewaraja, Yuni K

2013-09-01

264

Detection of human herpesvirus 8 by quantitative polymerase chain reaction: development and standardisation of methods  

PubMed Central

Background Human herpesvirus 8 (HHV-8), the aetiological agent of Kaposi’s sarcoma (KS), multicentric Castleman’s disease (MCD), and primary effusion lymphoma (PEL) is rare in Australia, but endemic in Sub-Saharan Africa, parts of South-east Asia and Oceania. While the treatment of external KS lesions can be monitored by clinical observation, the internal lesions of KS, MCD and PEL require extensive and expensive internal imaging, or autopsy. In patients with MCD and PEL, if HHV-8 viraemia is not reduced quickly, ~50% die within 24?months. HHV-8 qPCR is a valuable tool for monitoring HHV-8 viraemia, but is not available in many parts of the world, including those with high prevalence of KS and HHV-8. Methods A new molecular facility with stringent three-phase workflow was established, adhering to NPAAC and CLSI guidelines. Three fully validated quantitative assays were developed: two for detection and quantification of HHV-8; one for GAPDH, necessary for normalisation of viral loads in tissue and peripheral blood. Results The HHV-8 ORF73 and ORF26 qPCR assays were 100% specific. All qPCR assays, displayed a broad dynamic range (102 to 1010 copies/?L TE Buffer) with a limit of detection of 4.85x103, 5.61x102, and 2.59x102 copies/?L TE Buffer and a limit of quantification of 4.85x103, 3.01x102, and 1.38x102 copies/?L TE Buffer for HHV-8 ORF73, HHV-8 ORF26, and GAPDH respectively. The assays were tested on a panel of 35 KS biopsies from Queensland. All were HHV-8 qPCR positive with average viral load of 2.96x105 HHV-8 copies/?L DNA extract (range: 4.37x103 to 1.47x106 copies/?L DNA extract): When normalised these equate to an average viral load of 2.44x104 HHV-8 copies/103 cells (range: 2.20x102 to 7.38x105 HHV-8 copies/103 cells). Conclusions These are the first fully optimised, validated and MIQE compliant HHV-8 qPCR assays established in Australia. They worked well for qualitative detection of HHV-8 in archival tissue, and are well-suited for quantitative detection in whole blood. They are now available for research, for clinical diagnosis of HHV-8 infection, and for monitoring treatment efficacy.

2012-01-01

265

[Application of MALT-CLS method to FTIR quantitative analysis of atmospheric trace gas].  

PubMed

The MALT-CLS method for quantitative analysis of atmosphere trace gas by FTIR spectrometry was studied. Some experiments are described, such as long-path White cell, and passive remote sensing of aircraft. The characteristic of this method is that the calibration spectra are calculated from a database of absorption line parameters HITRAN using MALT program, including environmental and instrumental effects in the calculation. It is particularly useful in long open-path and solar FTIR spectroscopy, or passive remote sensing by FTIR. PMID:17020024

Gao, Min-Guang; Liu, Wen-Qing; Zhang, Tian-Shu; Liu, Jian-Guo; Lu, Yi-Huai; Xu, Liang; Zhu, Jun

2006-07-01

266

A rapid quantitative method of carisoprodol and meprobamate by liquid chromatography-tandem mass spectrometry.  

PubMed

The identification and quantitation of carisoprodol (Soma) and its chief metabolite meprobamate, which is also a clinically prescribed drug, remains a challenge for forensic toxicology laboratories. Carisoprodol and meprobamate are notable for their widespread use as muscle relaxants and their frequent identification in the blood of impaired drivers. Routine screening is possible in both an acidic/neutral pH screen and a traditional basic screen. An improvement in directed testing quantitations was desirable over the current options of an underivatized acidic/neutral extraction or a basic screen, neither of which used ideal internal standards. A new method was developed that utilized a simple protein precipitation, deuterated internal standards and a short 2-min isocratic liquid chromatography separation, followed by multiple reaction monitoring with tandem mass spectrometry. The linear quantitative range for carisoprodol was determined to be 1-35mg/L and for meprobamate was 0.5-50mg/L. The method was validated for specificity and selectivity, matrix effects, and accuracy and precision. PMID:23040985

Essler, Shannon; Bruns, Kerry; Frontz, Michael; McCutcheon, J Rod

2012-09-07

267

Quantitative Evaluation of the Matabolic Interactions between Trichloroethylene and 1,1-Dichloroethylene In vivo Using Gas Uptake Methods,  

National Technical Information Service (NTIS)

Quantitative Evaluation of the Metabolic Interactions between Trichloroethylene and 1,1-Dichloroethylene in Vivo Using Gas Uptake Methods. Gas uptake simulation methods were used to determine kinetic constants for trichloroethylene (TCE) and 1,1-dichloroe...

M. E. Anderson M. L. Gargas H. J. Clewell K. M. Severyn

1987-01-01

268

Using quantitative and qualitative data in health services research - what happens when mixed method findings conflict? [ISRCTN61522618  

PubMed Central

Background In this methodological paper we document the interpretation of a mixed methods study and outline an approach to dealing with apparent discrepancies between qualitative and quantitative research data in a pilot study evaluating whether welfare rights advice has an impact on health and social outcomes among a population aged 60 and over. Methods Quantitative and qualitative data were collected contemporaneously. Quantitative data were collected from 126 men and women aged over 60 within a randomised controlled trial. Participants received a full welfare benefits assessment which successfully identified additional financial and non-financial resources for 60% of them. A range of demographic, health and social outcome measures were assessed at baseline, 6, 12 and 24 month follow up. Qualitative data were collected from a sub-sample of 25 participants purposively selected to take part in individual interviews to examine the perceived impact of welfare rights advice. Results Separate analysis of the quantitative and qualitative data revealed discrepant findings. The quantitative data showed little evidence of significant differences of a size that would be of practical or clinical interest, suggesting that the intervention had no impact on these outcome measures. The qualitative data suggested wide-ranging impacts, indicating that the intervention had a positive effect. Six ways of further exploring these data were considered: (i) treating the methods as fundamentally different; (ii) exploring the methodological rigour of each component; (iii) exploring dataset comparability; (iv) collecting further data and making further comparisons; (v) exploring the process of the intervention; and (vi) exploring whether the outcomes of the two components match. Conclusion The study demonstrates how using mixed methods can lead to different and sometimes conflicting accounts and, using this six step approach, how such discrepancies can be harnessed to interrogate each dataset more fully. Not only does this enhance the robustness of the study, it may lead to different conclusions from those that would have been drawn through relying on one method alone and demonstrates the value of collecting both types of data within a single study. More widespread use of mixed methods in trials of complex interventions is likely to enhance the overall quality of the evidence base.

Moffatt, Suzanne; White, Martin; Mackintosh, Joan; Howel, Denise

2006-01-01

269

Quantitative and qualitative methods in UK health research: then, now and...?  

PubMed

This paper examines the current status of qualitative and quantitative research in the context of UK (public) health research in cancer. It is proposed that barren competition between qualitative and quantitative methods is inevitable, but that effective synergy between them continues to be essential to research excellence. The perceived methodological utility, with respect to understanding residual uncertainties, can account for the status accorded various research techniques and these will help to explain shifts witnessed in recent years and contribute towards an understanding of what can be realistically expected in terms of future progress. It is argued that the methodological debate, though familiar to many, is worthy of rearticulation in the context of cancer research where the psychosocial aspects of living with a cancer and the related complexity of providing appropriate cancer care are being addressed across Europe, as evidenced in recent directions in policy and research. PMID:12296843

McPherson, K; Leydon, G

2002-09-01

270

Validation of GC method for quantitative determination of residual 2-(2-chloroethoxy)ethanol (CEE) and N-methyl-2-pyrrolidinone (NMP) in pharmaceutical active substance.  

PubMed

The gas chromatography method with direct injection for quantitative determination of residual nonvolatile solvents such as 2-(2-chloroethoxy)ethanol (CEE) and N-methyl-2-pyrrolidinone (NMP) in quetiapine--the pharmaceutical active substance has been validated. Validation was performed according to the requirement of ICH validation guidelines Q2A and Q2B. Specificity, precision, accuracy, linearity, limits of detection and quantitation and robustness were determined and excellent results were obtained. PMID:21485288

Stolarczyk, Elzbieta U; Groman, Aleksandra; Maruszak, Wioleta

271

Crouzon syndrome: quantitative assessment of presenting deformity and surgical results based on CT scans.  

PubMed

We reviewed our experience with 14 children who presented sequentially with untreated Crouzon syndrome and whose cranial vault presentation was with bilateral coronal synostosis. Using a method of 14 measurements in the cranio-orbitozygomatic region taken from preoperative and postoperative CT scans in these patients, we documented their presenting skeletal morphology and the results of surgical correction at least 1 year after operation. Our preoperative measurements confirmed a widened anterior cranial vault at 108 percent of normal and a cranial length averaging only 92 percent of normal. In comparison with age-matched controls, orbital measurements revealed a widened anterior interorbital distance at 122 percent of normal, an increased intertemporal width at 121 percent of normal, globe protrusion at 119 percent of normal, and a short medial orbital wall distance at only 86 percent of normal. The distance between the zygomatic buttresses and the interarch distance were found to be increased at 106 and 103 percent of normal, respectively. The zygomatic arch lengths were substantially shortened at only 87 percent of age-matched control values. These findings confirmed clinical observations of brachycephalic anterior cranial vaults with shallow, hyperteloric orbits and globe proptosis. Generally, in these patients the midface is horizontally retrusive and transversely wide, reflected in wide and shortened zygomas. Assessment of the postoperative results at least 1 year later showed no significant changes in any craniofacial measurements. Our findings indicate that early surgical attempts to decompress and reshape the cranio-orbital regions may limit the effects of increased intracranial pressure but do not correct the deformity as judged by CT scan evaluation at least 1 year later. Over the period of the study, the Crouzon deformity did not worsen after surgery, but the measurements remained far from normal. PMID:8234498

Posnick, J C; Lin, K Y; Jhawar, B J; Armstrong, D

1993-11-01

272

New sensitive and quantitative analysis method for organic nitrogen compounds in urban aerosol samples.  

PubMed

Atmospheric aerosols contain a highly complex mixture of organic and inorganic compounds; however, as a chemical class relatively little is known about organic nitrogen (ON) content, with few satisfactory methods for speciated analysis. In this paper we report a sensitive and quantitative method for the speciation of ON within ambient atmospheric aerosol. Aerosol samples, collected on quartz microfiber filters, were extracted in water followed by solid phase extraction, elution, and concentration before analysis by comprehensive gas chromatography with a nitrogen chemiluminescence detection system (GCxGC-NCD). The NCD detection method was optimized using liquid standards. The GCxGC-NCD method showed high selectivity, sensitivity, and equimolarity in its response to individual organic compounds. Limits of detection (LOD) and limits of quantitation (LOQ) for four ON standards (1-nitropentane, o-toluidine, nonanenitrile, and quinoline) were determined to be in the range 0.16-0.27 pgN and 0.71-1.19 pgN, respectively. Between 21 and 57 different ON compounds were found in urban aerosol, (including 10 nitriles, 9 alkyl nitro compounds, 4 nitro-phenols, 4 amides, 3 nitrosamines, and 2 nitro-PAHs) on different dates from a city center location. Pyrrole (8.26-39.21 ngN m(-3) air) and N-butyl-benzenesulfonamide (6.23-20.87 ngN m(-3) air) were the most abundant ON compounds observed in all samples analyzed. The average mass loading of the total identified ON was 532.51 ngON m(-3) air. The sensitivity, selectivity, and relative ease of quantitation of unknown ON components makes the technique a significant improvement over previous laboratory methods. PMID:21210660

Özel, Mustafa Z; Hamilton, Jacqueline F; Lewis, Alastair C

2011-01-06

273

Generalized Finite Element Methods: Main Ideas, Results, and Perspective.  

National Technical Information Service (NTIS)

This paper is an overview of the main ideas of the Generalized Finite Element Method (GFEM). We present the basic results, experiences with, and potentials of this method. The GFEM is a generalization of the classical Finite Element Method in its h, p, an...

I. Babuska U. Banerjee J. E. Osborn

2004-01-01

274

Quantitative PCR methods for RNA and DNA in marine sediments: maximizing yield while overcoming inhibition.  

PubMed

For accurate quantification of DNA and RNA from environmental samples, yield loss during nucleic acid purification has to be minimized. Quantitative PCR (qPCR) and reverse transcription (RT)-qPCR require a trade-off between maximizing yield and removing inhibitors. We compared DNA and RNA yield and suitability for quantitative SYBR Green PCR and RT-PCR using the UltraClean and PowerSoil extraction kits and a bead-beating protocol with phenol/chloroform extraction steps. Purification methods included silica-column-based procedures from the MoBio kits, RNeasy MinElute, WizardPlus miniprep columns, and an acrylamide gel extraction. DNA and RNA purification with WizardPlus and RNeasy, respectively, led to significant losses of nucleic acids and archaeal 16S rRNA or 16S rRNA gene, as measured with RiboGreen or PicoGreen, and RT-qPCR or qPCR. Extraction and purification of DNA with the MoBio DNA UltraClean and DNA PowerSoil kits also decreased the yields slightly, relative to gel purification, in all sediments, except those from the deep sea in the Gulf of Mexico. Organic matter in humic-rich sediments may bind to these silica columns, reducing their nucleic acid-loading capacity. Purification with gel extraction cleans up organic-rich sediment samples sufficiently for quantitative analysis while avoiding the yield loss associated with commonly used silica columns. PMID:20059545

Lloyd, Karen G; Macgregor, Barbara J; Teske, Andreas

2009-12-07

275

Apparatus and method for quantitative assay of generic transuranic wastes from nuclear reactors  

DOEpatents

A combination of passive and active neutron measurements which yields quantitative information about the isotopic composition of transuranic wastes from nuclear power or weapons material manufacture reactors is described. From the measurement of prompt and delayed neutron emission and the incidence of two coincidentally emitted neutrons from induced fission of fissile material in the sample, one can quantify .sup.233 U, .sup.235 U and .sup.239 Pu isotopes in waste samples. Passive coincidence counting, including neutron multiplicity measurement and determination of the overall passive neutron flux additionally enables the separate quantitative evaluation of spontaneous fission isotopes such as .sup.240 Pu, .sup.244 Cm and .sup.252 Cf, and the spontaneous alpha particle emitter .sup.241 Am. These seven isotopes are the most important constituents of wastes from nuclear power reactors and once the mass of each isotope present is determined by the apparatus and method of the instant invention, the overall alpha particle activity can be determined to better than 1 nCi/g from known radioactivity data. Therefore, in addition to the quantitative analysis of the waste sample useful for later reclamation purposes, the alpha particle activity can be determined to decide whether "permanent" low-level burial is appropriate for the waste sample.

Caldwell, John T. (Los Alamos, NM); Kunz, Walter E. (Santa Fe, NM); Atencio, James D. (Los Alamos, NM)

1984-01-01

276

Quantitative validation of the 3D SAR profile of hyperthermia applicators using the gamma method  

NASA Astrophysics Data System (ADS)

For quality assurance of hyperthermia treatment planning systems, quantitative validation of the electromagnetic model of an applicator is essential. The objective of this study was to validate a finite-difference time-domain (FDTD) model implementation of the Lucite cone applicator (LCA) for superficial hyperthermia. The validation involved (i) the assessment of the match between the predicted and measured 3D specific absorption rate (SAR) distribution, and (ii) the assessment of the ratio between model power and real-world power. The 3D SAR distribution of seven LCAs was scanned in a phantom bath using the DASY4 dosimetric measurement system. The same set-up was modelled in SEMCAD X. The match between the predicted and the measured SAR distribution was quantified with the gamma method, which combines distance-to-agreement and dose difference criteria. Good quantitative agreement was observed: more than 95% of the measurement points met the acceptance criteria 2 mm/2% for all applicators. The ratio between measured and predicted power absorption ranged from 0.75 to 0.92 (mean 0.85). This study shows that quantitative validation of hyperthermia applicator models is feasible and is worth considering as a part of hyperthermia quality assurance procedures.

de Bruijne, Maarten; Samaras, Theodoros; Chavannes, Nicolas; van Rhoon, Gerard C.

2007-06-01

277

Quantitative validation of the 3D SAR profile of hyperthermia applicators using the gamma method.  

PubMed

For quality assurance of hyperthermia treatment planning systems, quantitative validation of the electromagnetic model of an applicator is essential. The objective of this study was to validate a finite-difference time-domain (FDTD) model implementation of the Lucite cone applicator (LCA) for superficial hyperthermia. The validation involved (i) the assessment of the match between the predicted and measured 3D specific absorption rate (SAR) distribution, and (ii) the assessment of the ratio between model power and real-world power. The 3D SAR distribution of seven LCAs was scanned in a phantom bath using the DASY4 dosimetric measurement system. The same set-up was modelled in SEMCAD X. The match between the predicted and the measured SAR distribution was quantified with the gamma method, which combines distance-to-agreement and dose difference criteria. Good quantitative agreement was observed: more than 95% of the measurement points met the acceptance criteria 2 mm/2% for all applicators. The ratio between measured and predicted power absorption ranged from 0.75 to 0.92 (mean 0.85). This study shows that quantitative validation of hyperthermia applicator models is feasible and is worth considering as a part of hyperthermia quality assurance procedures. PMID:17505090

de Bruijne, Maarten; Samaras, Theodoros; Chavannes, Nicolas; van Rhoon, Gerard C

2007-05-08

278

Quantitative Community Fingerprinting Methods for Estimating the Abundance of Operational Taxonomic Units in Natural Microbial Communities?  

PubMed Central

Molecular fingerprinting techniques offer great promise for analyzing changes in microbial community structure, especially when dealing with large number of samples. However, a serious limitation has been the lack of quantification offered by such techniques since the relative abundances of the identified operational taxonomic units (OTUs) in the original samples are not measured. A quantitative fingerprinting approach designated “qfingerprinting” is proposed here. This method involves serial dilutions of the sample of interest and further systematic fingerprinting of all dilution series. Using the ultimate dilutions for which OTU are still PCR amplifiable and taking into account peak size inaccuracy and peak reproducibility, the relative abundance of each OTU is then simultaneously determined over a scale spanning several orders of magnitude. The approach was illustrated by using a quantitative version of automated ribosomal intergenic spacer analysis (ARISA), here called qARISA. After validating the concept with a synthetic mixture of known DNA targets, qfingerprinting was applied to well-studied marine sediment samples to examine specific changes in OTU abundance associated with sediment depth. The new strategy represents a major advance for the detailed quantitative description of specific OTUs within complex communities. Further ecological applications of the new strategy are also proposed.

Ramette, Alban

2009-01-01

279

Quantitative community fingerprinting methods for estimating the abundance of operational taxonomic units in natural microbial communities.  

PubMed

Molecular fingerprinting techniques offer great promise for analyzing changes in microbial community structure, especially when dealing with large number of samples. However, a serious limitation has been the lack of quantification offered by such techniques since the relative abundances of the identified operational taxonomic units (OTUs) in the original samples are not measured. A quantitative fingerprinting approach designated "qfingerprinting" is proposed here. This method involves serial dilutions of the sample of interest and further systematic fingerprinting of all dilution series. Using the ultimate dilutions for which OTU are still PCR amplifiable and taking into account peak size inaccuracy and peak reproducibility, the relative abundance of each OTU is then simultaneously determined over a scale spanning several orders of magnitude. The approach was illustrated by using a quantitative version of automated ribosomal intergenic spacer analysis (ARISA), here called qARISA. After validating the concept with a synthetic mixture of known DNA targets, qfingerprinting was applied to well-studied marine sediment samples to examine specific changes in OTU abundance associated with sediment depth. The new strategy represents a major advance for the detailed quantitative description of specific OTUs within complex communities. Further ecological applications of the new strategy are also proposed. PMID:19201961

Ramette, Alban

2009-02-06

280

Depth determination for shallow teleseismic earthquakes Methods and results  

SciTech Connect

Contemporary methods used to determine depths of moderate-sized shallow teleseismic earthquakes are described. These include techniques based on surface wave spectra, and methods which estimate focal depth from the waveforms of body waves. The advantages of different methods and their limitations are discussed, and significant results for plate tectonics, obtained in the last five years by the application of these methods, are presented. 119 references.

Stein, S.; Wiens, D.A.

1986-11-01

281

Problems of a thermionic space NPS reactor unit quantitative reliability assessment on the basis of ground development results  

SciTech Connect

The paper sets forth major problems that arose in the course of a quantitative assessment of reliability of a TOPAZ-2 space NPS reactor unit performed on the basis of ground development results. Proposals are made on the possible ways to solve those problems through development and introduction of individual standards especially for the ground development stage, which would specify the assessment algorithm and censoring rules, and exclude a number of existing uncertainties when making a decision on going to flight testing.

Ponomarev-Stepnoi, Nikolai N.; Nechaev, Yuri A.; Khazanovich, Igor M.; Samodelov, Victor N.; Pavlov, Konstantin A. [RRC 'Kurchatov Institute' Moscow 123182 (Russian Federation); Russian Federation Ministry of Defense Central Scientific-Research Institute of Space Force Moscow K-160 (Russian Federation)

1997-01-10

282

Development and evaluation of event-specific quantitative PCR method for genetically modified soybean A2704-12.  

PubMed

A novel real-time PCR-based analytical method was developed for the event-specific quantification of a genetically modified (GM) soybean event; A2704-12. During the plant transformation, DNA fragments derived from pUC19 plasmid were integrated in A2704-12, and the region was found to be A2704-12 specific. The pUC19-derived DNA sequences were used as primers for the specific detection of A2704-12. We first tried to construct a standard plasmid for A2704-12 quantification using pUC19. However, non-specific signals appeared with both qualitative and quantitative PCR analyses using the specific primers with pUC19 as a template, and we then constructed a plasmid using pBR322. The conversion factor (C(f)), which is required to calculate the amount of the genetically modified organism (GMO), was experimentally determined with two real-time PCR instruments, the Applied Biosystems 7900HT and the Applied Biosystems 7500. The determined C(f) values were both 0.98. The quantitative method was evaluated by means of blind tests in multi-laboratory trials using the two real-time PCR instruments. The limit of quantitation for the method was estimated to be 0.1%. The trueness and precision were evaluated as the bias and reproducibility of relative standard deviation (RSD(R)), and the determined bias and RSD(R) values for the method were each less than 20%. These results suggest that the developed method would be suitable for practical analyses for the detection and quantification of A2704-12. PMID:21515963

Takabatake, Reona; Akiyama, Hiroshi; Sakata, Kozue; Onishi, Mari; Koiwa, Tomohiro; Futo, Satoshi; Minegishi, Yasutaka; Teshima, Reiko; Mano, Junichi; Furui, Satoshi; Kitta, Kazumi

2011-01-01

283

Exploring the use of storytelling in quantitative research fields using a multiple case study method  

NASA Astrophysics Data System (ADS)

The purpose of this study was to explore the emerging use of storytelling in quantitative research fields. The focus was not on examining storytelling in research, but rather how stories are used in various ways within the social context of quantitative research environments. In-depth interviews were conducted with seven professionals who had experience using storytelling in their work and my personal experience with the subject matter was also used as a source of data according to the notion of researcher-as-instrument. This study is qualitative in nature and is guided by two supporting theoretical frameworks, the sociological perspective and narrative inquiry. A multiple case study methodology was used to gain insight about why participants decided to use stories or storytelling in a quantitative research environment that may not be traditionally open to such methods. This study also attempted to identify how storytelling can strengthen or supplement existing research, as well as what value stories can provide to the practice of research in general. Five thematic findings emerged from the data and were grouped under two headings, "Experiencing Research" and "Story Work." The themes were found to be consistent with four main theoretical functions of storytelling identified in existing scholarly literature: (a) sense-making; (b) meaning-making; (c) culture; and (d) communal function. The five thematic themes that emerged from this study and were consistent with the existing literature include: (a) social context; (b) quantitative versus qualitative; (c) we think and learn in terms of stories; (d) stories tie experiences together; and (e) making sense and meaning. Recommendations are offered in the form of implications for various social contexts and topics for further research are presented as well.

Matthews, Lori N. Hamlet

284

Quantitative 1H NMR: Development and Potential of an Analytical Method - an Update  

PubMed Central

Covering the literature from mid-2004 until the end of 2011, this review continues a previous literature overview on quantitative 1H NMR (qHNMR) methodology and its applications in the analysis of natural products (NPs). Among the foremost advantages of qHNMR is its accurate function with external calibration, the lack of any requirement for identical reference materials, a high precision and accuracy when properly validated, and an ability to quantitate multiple analytes simultaneously. As a result of the inclusion of over 170 new references, this updated review summarizes a wealth of detailed experiential evidence and newly developed methodology that supports qHNMR as a valuable and unbiased analytical tool for natural product and other areas of research.

Pauli, Guido F.; Godecke, Tanja; Jaki, Birgit U.; Lankin, David C.

2012-01-01

285

A robust method for quantitative high-throughput analysis of proteomes by 18O labeling.  

PubMed

MS-based quantitative proteomics plays an increasingly important role in biological and medical research and the development of these techniques remains one of the most important challenges in mass spectrometry. Numerous stable isotope labeling approaches have been proposed. However, and particularly in the case of (18)O-labeling, a standard protocol of general applicability is still lacking, and statistical issues associated to these methods remain to be investigated. In this work we present an improved high-throughput quantitative proteomics method based on whole proteome concentration by SDS-PAGE, optimized in-gel digestion, peptide (18)O-labeling, and separation by off-gel isoelectric focusing followed by liquid chromatography-LIT-MS. We demonstrate that the off-gel technique is fully compatible with (18)O peptide labeling in any pH range. A recently developed statistical model indicated that partial digestions and methionine oxidation do not alter protein quantification and that variances at the scan, peptide, and protein levels are stable and reproducible in a variety of proteomes of different origin. We have also analyzed the dynamic range of quantification and demonstrated the practical utility of the method by detecting expression changes in a model of activation of Jurkat T-cells. Our protocol provides a general approach to perform quantitative proteomics by (18)O-labeling in high-throughput studies, with the added value that it has a validated statistical model for the null hypothesis. To the best of our knowledge, this is the first report where a general protocol for stable isotope labeling is tested in practice using a collection of samples and analyzed at this degree of statistical detail. PMID:20807836

Bonzon-Kulichenko, Elena; Pérez-Hernández, Daniel; Núñez, Estefanía; Martínez-Acedo, Pablo; Navarro, Pedro; Trevisan-Herraz, Marco; Ramos, María del Carmen; Sierra, Saleta; Martínez-Martínez, Sara; Ruiz-Meana, Marisol; Miró-Casas, Elizabeth; García-Dorado, David; Redondo, Juan Miguel; Burgos, Javier S; Vázquez, Jesús

2010-08-31

286

Quantitative method for the separation of chlorophylls a and b from phytoplankton pigments by high pressure liquid chromatography  

Microsoft Academic Search

A rapid quantitative high pressure liquid chromatographic (HPLC) method is described for the determination of nanogram amounts of chlorophyll a and b. Comparison of the HPLC method with classical spectrophotometric and fluorometric methods has shown the inaccuracy of the latter methods in separating chlorophyll a from the pigment matrix found in biological samples. The HPLC method offers increased sensitivity, compatibility

1978-01-01

287

Apparatus and method for quantitative determination of materials contained in fluids  

DOEpatents

Apparatus and method for near real-time in-situ monitoring of particulates and vapors contained in fluids. Initial filtration of a known volume of the fluid sample is combined with laser-induced dielectric breakdown spectroscopy of the filter employed to obtain qualitative and quantitative information with high sensitivity. Application of the invention to monitoring of beryllium, beryllium oxide, or other beryllium-alloy dusts is demonstrated. Significant shortening of analysis time is achieved from those of the usual chemical techniques of analysis.

Radziemski, Leon J. (Los Alamos, NM); Cremers, David A. (Los Alamos, NM)

1985-01-01

288

Apparatus and method for quantitative determination of materials contained in fluids  

DOEpatents

Apparatus and method for near real-time in-situ monitoring of particulates and vapors contained in fluids are described. Initial filtration of a known volume of the fluid sample is combined with laser-induced dielectric breakdown spectroscopy of the filter employed to obtain qualitative and quantitative information with high sensitivity. Application of the invention to monitoring of beryllium, beryllium oxide, or other beryllium-alloy dusts is shown. Significant shortening of analysis time is achieved from the usual chemical techniques of analysis.

Radziemski, L.J.; Cremers, D.A.

1982-09-07

289

A Rapid, Quantitative Method to Characterize The Human Lymphocyte Concentration for Automated High-Throughput Radiation Biodosimetry  

PubMed Central

We have developed a Quantitative Light Absorption Analysis (QLAA) method to rapidly estimate human lymphocyte concentrations isolated from small volumes of whole blood. Measurements of the light absorption analysis were calibrated for lymphocyte concentration levels using a hemocytometer. To validate the QLAA system, blood samples were collected from 17 healthy donors and lymphocyte absorption measurements were directly compared with the manual microscope counting. The results showed that lymphocyte measurements obtained using the QLAA system were comparable with the manually scored lymphocyte counts but with measurements taken in seconds.

Xu, Yanping; Turner, Helen C.; Garty, Guy; Brenner, David

2013-01-01

290

A Rapid, Quantitative Method to Characterize The Human Lymphocyte Concentration for Automated High-Throughput Radiation Biodosimetry.  

PubMed

We have developed a Quantitative Light Absorption Analysis (QLAA) method to rapidly estimate human lymphocyte concentrations isolated from small volumes of whole blood. Measurements of the light absorption analysis were calibrated for lymphocyte concentration levels using a hemocytometer. To validate the QLAA system, blood samples were collected from 17 healthy donors and lymphocyte absorption measurements were directly compared with the manual microscope counting. The results showed that lymphocyte measurements obtained using the QLAA system were comparable with the manually scored lymphocyte counts but with measurements taken in seconds. PMID:23781493

Xu, Yanping; Turner, Helen C; Garty, Guy; Brenner, David

2013-03-01

291

A quantitative method for the measurement of membrane affinity by polydiacetylene-based colorimetric assay.  

PubMed

The measurement of membrane affinity is an important early screening step during drug discovery. However, classical methods for membrane affinity measurement are tedious and difficult to implement in high-throughput screening. This article describes a quantitative method for the measurement of membrane affinity by colorimetric assay based on polydiacetylene (PDA) sensors. Prepared lipid/PDA chromatic vesicles were used to model cell membranes. By measuring the colorimetric response of the chromatic vesicles when drug-membrane interactions occurred, membrane affinity constant K(b) could be calculated using a simple quantitative model. Under optimized preparation conditions, the calculated log(K(b)) values exhibited an in-batch relative standard deviation (RSD) of less than 4% and a between-batch RSD of less than 8% for all three reference compounds. The logarithm of K(b) of the six ?-blockers exhibited excellent linear correlation with the logarithm of the liposome/water partition coefficient (K(m)) with R(2)=0.9793. For neutral compounds, the log(K(b)) of n-fatty alcohols correlated with the logarithm of the n-octanol/water partition coefficient (K(oct)) with a linear correlation coefficient R(2)=0.9833. This work provides a simple, convenient, and reproducible method for the rapid measurement of membrane affinity and presents important implications for high-throughput screening. PMID:22019766

Zheng, Feng; Wu, Zheng; Chen, Yihua

2011-10-03

292

A Method to Prioritize Quantitative Traits and Individuals for Sequencing in Family-Based Studies  

PubMed Central

Owing to recent advances in DNA sequencing, it is now technically feasible to evaluate the contribution of rare variation to complex traits and diseases. However, it is still cost prohibitive to sequence the whole genome (or exome) of all individuals in each study. For quantitative traits, one strategy to reduce cost is to sequence individuals in the tails of the trait distribution. However, the next challenge becomes how to prioritize traits and individuals for sequencing since individuals are often characterized for dozens of medically relevant traits. In this article, we describe a new method, the Rare Variant Kinship Test (RVKT), which leverages relationship information in family-based studies to identify quantitative traits that are likely influenced by rare variants. Conditional on nuclear families and extended pedigrees, we evaluate the power of the RVKT via simulation. Not unexpectedly, the power of our method depends strongly on effect size, and to a lesser extent, on the frequency of the rare variant and the number and type of relationships in the sample. As an illustration, we also apply our method to data from two genetic studies in the Old Order Amish, a founder population with extensive genealogical records. Remarkably, we implicate the presence of a rare variant that lowers fasting triglyceride levels in the Heredity and Phenotype Intervention (HAPI) Heart study (p?=?0.044), consistent with the presence of a previously identified null mutation in the APOC3 gene that lowers fasting triglyceride levels in HAPI Heart study participants.

Shah, Kaanan P.; Douglas, Julie A.

2013-01-01

293

A method to prioritize quantitative traits and individuals for sequencing in family-based studies.  

PubMed

Owing to recent advances in DNA sequencing, it is now technically feasible to evaluate the contribution of rare variation to complex traits and diseases. However, it is still cost prohibitive to sequence the whole genome (or exome) of all individuals in each study. For quantitative traits, one strategy to reduce cost is to sequence individuals in the tails of the trait distribution. However, the next challenge becomes how to prioritize traits and individuals for sequencing since individuals are often characterized for dozens of medically relevant traits. In this article, we describe a new method, the Rare Variant Kinship Test (RVKT), which leverages relationship information in family-based studies to identify quantitative traits that are likely influenced by rare variants. Conditional on nuclear families and extended pedigrees, we evaluate the power of the RVKT via simulation. Not unexpectedly, the power of our method depends strongly on effect size, and to a lesser extent, on the frequency of the rare variant and the number and type of relationships in the sample. As an illustration, we also apply our method to data from two genetic studies in the Old Order Amish, a founder population with extensive genealogical records. Remarkably, we implicate the presence of a rare variant that lowers fasting triglyceride levels in the Heredity and Phenotype Intervention (HAPI) Heart study (p?=?0.044), consistent with the presence of a previously identified null mutation in the APOC3 gene that lowers fasting triglyceride levels in HAPI Heart study participants. PMID:23626830

Shah, Kaanan P; Douglas, Julie A

2013-04-23

294

A method for the qualitative and quantitative detection of individual NH +4-containing aerosols  

NASA Astrophysics Data System (ADS)

A quantitative and selective method for the identification of individual NH +4-containing aerosols has been developed. The method, a so-called spot test, is based on a chemical reaction between ammonium salts and a NaBØ 4 film. The test can be applied for the detection of submicrometer and micrometer size atmospheric particles. It is specific for NH +4 ions, the only interference found is a reaction of K + ions with the reagent film, but the spots are distinguishable by morphology. Furthermore, it is possible to distinguish between pure and mixed NH +4 particles, even insoluble particles containing NH +4 compounds on the surface are detectable. By fixing the reagent film thickness and the relative humidity, a correlation between the NH +4 mass of the particle and the halo-diameter can be established. Using this method the usual sampling time for the aerosols should be in the order of minutes.

Weisweiler, W. K.; Schwarz, B. U.

295

Sample preparation methods for quantitative detection of DNA by molecular assays and marine biosensors.  

PubMed

The need for quantitative molecular methods is growing in environmental, food, and medical fields but is hindered by low and variable DNA extraction and by co-extraction of PCR inhibitors. DNA extracts from Enterococcus faecium, seawater, and seawater spiked with E. faecium and Vibrio parahaemolyticus were tested by qPCR for target recovery and inhibition. Conventional and novel methods were tested, including Synchronous Coefficient of Drag Alteration (SCODA) and lysis and purification systems used on an automated genetic sensor (the Environmental Sample Processor, ESP). Variable qPCR target recovery and inhibition were measured, significantly affecting target quantification. An aggressive lysis method that utilized chemical, enzymatic, and mechanical disruption enhanced target recovery compared to commercial kit protocols. SCODA purification did not show marked improvement over commercial spin columns. Overall, data suggested a general need to improve sample preparation and to accurately assess and account for DNA recovery and inhibition in qPCR applications. PMID:23790450

Cox, Annie M; Goodwin, Kelly D

2013-06-20

296

Spectroscopic characterization and quantitative determination of atorvastatin calcium impurities by novel HPLC method  

NASA Astrophysics Data System (ADS)

Seven process related impurities were identified by LC-MS in the atorvastatin calcium drug substance. These impurities were identified by LC-MS. The structure of impurities was confirmed by modern spectroscopic techniques like 1H NMR and IR and physicochemical studies conducted by using synthesized authentic reference compounds. The synthesized reference samples of the impurity compounds were used for the quantitative HPLC determination. These impurities were detected by newly developed gradient, reverse phase high performance liquid chromatographic (HPLC) method. The system suitability of HPLC analysis established the validity of the separation. The analytical method was validated according to International Conference of Harmonization (ICH) with respect to specificity, precision, accuracy, linearity, robustness and stability of analytical solutions to demonstrate the power of newly developed HPLC method.

Gupta, Lokesh Kumar

2012-11-01

297

A method for estimating the effective number of loci affecting a quantitative character.  

PubMed

A likelihood method is introduced that jointly estimates the number of loci and the additive effect of alleles that account for the genetic variance of a normally distributed quantitative character in a randomly mating population. The method assumes that measurements of the character are available from one or both parents and an arbitrary number of full siblings. The method uses the fact, first recognized by Karl Pearson in 1904, that the variance of a character among offspring depends on both the parental phenotypes and on the number of loci. Simulations show that the method performs well provided that data from a sufficient number of families (on the order of thousands) are available. This method assumes that the loci are in Hardy-Weinberg and linkage equilibrium but does not assume anything about the linkage relationships. It performs equally well if all loci are on the same non-recombining chromosome provided they are in linkage equilibrium. The method can be adapted to take account of loci already identified as being associated with the character of interest. In that case, the method estimates the number of loci not already known to affect the character. The method applied to measurements of crown-rump length in 281 family trios in a captive colony of African green monkeys (Chlorocebus aethiopus sabaeus) estimates the number of loci to be 112 and the additive effect to be 0.26 cm. A parametric bootstrap analysis shows that a rough confidence interval has a lower bound of 14 loci. PMID:23973416

Slatkin, Montgomery

2013-08-22

298

Quantitative monoclonal antibody determination of estrogen and progesterone receptors in human breast cancer: correlation with the radioligand method.  

PubMed

To assess the possibility of substituting our routine method (dextran-coated charcoal, DCC) of determining estrogen (ER) and progesterone receptors (PR) for an enzyme immunoassay technique (EIA), we compared the two methods for determination of the two types of receptor in breast cancer specimens. In terms of sample positivity or negativity, the two techniques agreed in 76 of the 82 samples analyzed for ER (92.7%; p < 0.001), and in 65 out of 75 samples assayed for PR (86.6%; p < 0.001). Quantitative analysis of the data showed a significant correlation between DCC and EIA for both ER (r = 0.84; p < 0.0001) and PR (r = 0.77; p < 0.0001). The results suggest the usefulness of EIA in substituting DCC, although further clinical studies are required to fully evaluate this new method. PMID:8052485

Jarque, F; Lluch, A; Vizcarra, E; Muñoz, M; Alberola, V; Garciá-Conde, J

299

Assessment of Riboflavin as a Tracer Substance: Comparison of a Qualitative to a Quantitative Method of Riboflavin Measurement  

PubMed Central

Background Noncompliance with medications may have major impacts on outcomes measured in research, potentially distorting the validity of controlled clinical trials. Riboflavin is frequently used in trials as a marker of adherence. It can be combined with study medication and is excreted in urine where it fluoresces under UV light. This study compares qualitative visual inspection of fluorescence to quantitative fluorometric analysis of riboflavin concentration in its ability to detect the presence of riboflavin in urine. Methods Twenty-four volunteers received 0 mg, 25 mg, and 50 mg doses of riboflavin under single-blind conditions, with 20 also receiving a 100 mg dose. Five serial urine samples were collected over the following 36 hours. Quantitative measurement of riboflavin by fluorometric analysis and qualitative assessment of each sample using visual inspection were performed. Results The overall false positive rate for qualitative assessment was 53%. For quantitative assessment, a riboflavin concentration of 900 ng/mL was established to classify positive samples. More than 80% of samples were positive 2 to 24 hours following ingestion of 25 mg and 50 mg, and less than 80% were positive at 36 hours. At least 95% of observations for the 100 mg dose were above 900 ng/mL at all timepoints. Conclusions Quantitative fluorometric assessment is superior to qualitative visual inspection alone in determining medication adherence. The combination of 25–50 mg of daily riboflavin and a cut-off level of 900 ng/mL allows for the acceptable sensitivity of missing detection of non-compliant participants while preserving a high level of power to detect all cases of medication compliance.

Herron, Abigail J.; Mariani, John J.; Pavlicova, Martina; Parinello, Christina M.; Bold, Krysten W.; Levin, Frances R.; Nunes, Edward V.; Sullivan, Maria A.; Raby, Wilfred N.; Bisaga, Adam

2013-01-01

300

Instrumentation and quantitative methods of evaluation. Comprehensive three-year progress report, January 15, 1989-July 15, 1991.  

National Technical Information Service (NTIS)

This report summarizes goals and accomplishments of the research program entitled Instrumentation and Quantitative Methods of Evaluation, during the period January 15, 1989 through July 15, 1991. This program is very closely integrated with the radiopharm...

R. N. Beck M. D. Cooper

1991-01-01

301

Quantitative Methods for Long-Range Environmental Forecasting. Long-Wave European Projections. Volume II. Technical Volume.  

National Technical Information Service (NTIS)

The overall purpose of this Interim Technical Report is to provide a basis for the improvements of long-range environmental forecasting through the use of quantitative methods. This volume provides the technical discussion of the model that was developed ...

G. R. Franco H. M. Weil A. Greenberg L. German D. Hartwick

1974-01-01

302

[Quantitative processing of results of uniparametric fluorescent flow analysis of human chromosomes].  

PubMed

The proposed procedure of computer analysis of the flow karyotype data, obtained in human chromosomes studies, is able to provide information about the basic parameters of the karyotypes: the positions of the peaks (corresponding to the relative size of chromosomes), peaks areas (relative number of chromosomes in the sample), coefficients of variation (CV) of the peaks--possible differences between homologous chromosomes. The analysis is based on the assumption that all chromosomal components of the experimental distributions are normal (Gaussians). The algorithm of the analysis uses a combination of two approaches: truncation method and least squares method. As the flow data are "contaminated" by background components, special tools for filtering off the contaminating signals were designed including the original integral Fourier filtering procedure. This analysis is realized in a program package utilizing IBM-compatible PCs. The user is able to get the desired parameters for most chromosomes of the karyotype under study from univariate flow data: differences between particular homologous chromosomes, presence of chromosome aberrations, extra chromosomes, etc., since structural aberrations and chromosome number variation lead to specific changes of the parameters of chromosome-related components. PMID:7990817

Kravatski?, Iu V; Poletaev, A I

303

Defining the knee joint flexion–extension axis for purposes of quantitative gait analysis: An evaluation of methods  

Microsoft Academic Search

Minimising measurement variability associated with hip axial rotation and avoiding knee joint angle cross-talk are two fundamental objectives of any method used to define the knee joint flexion–extension axis for purposes of quantitative gait analysis. The aim of this experiment was to compare three different methods of defining this axis: the knee alignment device (KAD) method, a method based on

Anthony G. Schache; Richard Baker; Larry W. Lamoreux

2006-01-01

304

Age-related changes in rat cerebellar basket cells: a quantitative study using unbiased stereological methods  

PubMed Central

Cortical cerebellar basket cells are stable postmitotic cells; hence, they are liable to endure age-related changes. Since the cerebellum is a vital organ for the postural control, equilibrium and motor coordination, we aimed to determine the quantitative morphological changes in those interneurons with the ageing process, using unbiased techniques. Material from the cerebellar cortex (Crus I and Crus II) was collected from female rats aged 2, 6, 9, 12, 15, 18, 21 and 24 mo (5 animals per each age group), fixed by intracardiac perfusion, and processed for transmission electron microscopy, using conventional techniques. Serial semithin sections were obtained (5 blocks from each rat), enabling the determination of the number-weighted mean nuclear volume (by the nucleator method). On ultrathin sections, 25 cell profiles from each animal were photographed. The volume density of the nucleus, ground substance, mitochondria, Golgi apparatus (Golgi) and dense bodies (DB), and the mean surface density of the rough endoplasmic reticulum (RER) were determined, by point counting, using a morphometric grid. The mean total volumes of the soma and organelles and the mean total surface area of the RER [s?N (RER)] were then calculated. The results were analysed with 1-way ANOVA; posthoc pairwise comparisons of group means were performed using the Newman-Keuls test. The relation between age and each of the parameters was studied by regression analysis. Significant age-related changes were observed for the mean volumes of the soma, ground substance, Golgi, DB, and s?N (RER). Positive linear trends were found for the mean volumes of the ground substance, Golgi, and DB; a negative linear trend was found for the s?N (RER). These results indicate that rat cerebellar basket cells endure important age-related changes. The significant decrease in the s?N (RER) may be responsible for a reduction in the rate of protein synthesis. Additionally, it may be implicated in a cascade of events leading to cell damage due to the excitotoxic activity of glutamate, which could interfere in the functioning of the complex cerebellar neuronal network.

HENRIQUE, RUI M. F.; ROCHA, EDUARDO; REIS, ALCINDA; MARCOS, RICARDO; OLIVEIRA, MARIA H.; SILVA, MARIA W.; MONTEIRO, ROGERIO A. F.

2001-01-01

305

The Use of Multiple Markers in a Bayesian Method for Mapping Quantitative Trait Loci  

PubMed Central

Information on multiple linked genetic markers was used in a Bayesian method for the statistical mapping of quantitative trait loci (QTL). Bayesian parameter estimation and hypothesis testing were implemented via Markov chain Monte Carlo algorithms. Variables sampled were the augmented data (marker-QTL genotypes, polygenic effects), an indicator variable for linkage or nonlinkage, and the parameters. The parameter vector included allele frequencies at the markers and the QTL, map distances of the markers and the QTL, QTL substitution effect, and polygenic and residual variances. The criterion for QTL detection was the marginal posterior probability of a QTL being located on the chromosome carrying the markers. The method was evaluated empirically by analyzing simulated granddaughter designs consisting of 2000 sons, 20 related sires, and their ancestors.

Uimari, P.; Thaller, G.; Hoeschele, I.

1996-01-01

306

An Image Analysis Method for the Precise Selection and Quantitation of Fluorescently Labeled Cellular Constituents  

PubMed Central

The accurate measurement of the morphological characteristics of cells with nonuniform conformations presents difficulties. We report here a straightforward method using immunofluorescent staining and the commercially available imaging program Adobe Photoshop, which allows objective and precise information to be gathered on irregularly shaped cells. We have applied this measurement technique to the analysis of human muscle cells and their immunologically marked intracellular constituents, as these cells are prone to adopting a highly branched phenotype in culture. Use of this method can be used to overcome many of the long-standing limitations of conventional approaches for quantifying muscle cell size in vitro. In addition, wider applications of Photoshop as a quantitative and semiquantitative tool in immunocytochemistry are explored.

Agley, Chibeza C.; Velloso, Cristiana P.; Lazarus, Norman R.

2012-01-01

307

Sensitivity analysis of quantitative fracture criterion based on the results of the SICO test  

Microsoft Academic Search

Results of numerical simulation of the SICO test, including the resistance heating of samples and metal flow during the test, are described in this paper. The main goal of the work is the determination of the sensitivity of fracture criteria with respect to the test parameters: temperature, die velocity and material parameters—strain rate sensitivity, hardening coefficient, hardening exponent and temperature

L. Trebacz; D. Szeliga; M. Pietrzyk

2006-01-01

308

A quantitative method for detecting deposits of amyloid A protein in aspirated fat tissue of patients with arthritis  

PubMed Central

OBJECTIVE—To describe a new, quantitative, and reproducible method for detecting deposits of amyloid A protein in aspirated fat tissue and to compare it with smears stained with Congo red.?METHODS—After extraction of at least 30 mg of abdominal fat tissue in guanidine, the amyloid A protein concentration was measured by a monoclonal antibody-based sandwich ELISA.?RESULTS—The concentrations in 24 patients with arthritis and AA amyloidosis (median 236, range 1.1-8530 ng/mg tissue) were higher (p<0.001) than in non-arthritic controls, uncomplicated rheumatoid arthritis, and other types of systemic amyloidosis (median 1.1, range 1.1-11.6 ng/mg tissue). Patients with extensive deposits, according to Congo red staining, had higher concentrations than patients with minute deposits.?CONCLUSION—This is a new, quantitative, and reproducible method for detecting deposits of amyloid A protein in aspirated fat tissue of patients with arthritis, even when minute deposits are present as detected in smears stained with Congo red.?? Keywords: amyloid A protein; fat tissue; arthritis

Hazenberg, B.; Limburg, P.; Bijzet, J.; van Rijswijk, M. H

1999-01-01

309

[A quantitative method using one marker for simultaneous assay of ginsenosides in Panax ginseng and P. notoginseng].  

PubMed

Current quality control patterns are limited to industrial application, for most of the natural chemical reference substances are expensive and unavailable. Herein, a method, quantitative analysis of multi-components with single marker (QAMS), was established and validated to simultaneously determine nine ginsenosides (ginsenoside Rg1, Re, Rf, Rh1, Rb1, Rc, Rb2, Rb3, Rd) in P. ginseng and four ginsenosides (ginsenoside Rg1, Rh1, Rb1, Rd) in P. notoginseng. Using ginsenoside Rb1 as the contrast, the relative correction factors (RCF) of the other eight ginsenosides were determined by HPLC-DAD. Within the linear ranges, the values of RCF of ginsenoside Rb1 to ginsenoside Rg1, Re, Rf, Rh1, Rc, Rb2, Rb3 and Rd were 1.400, 1.215, 1.517, 1.801, 0.944, 1.012, 1.143, and 1.135, respectively. The RCF had a good reproducibility in various instruments, chromatographic columns (RSD = 0.30% - 3.9%). According to their RCF, we simultaneously determined nine ginsenosides in P. ginseng only using one marker. In addition, the RCF of ginsenosides were used to simultaneously quantitative analysis of four ginsenosides in P. notoginseng. The results of QAMS method were validated by comparing with that of external standard method, and no obvious significant difference was found. PMID:19244752

Zhu, Jing-jing; Wang, Zhi-min; Kuang, Yan-hui; Zhang, Qi-wei; Gao, Qi-pin; Ma, Ni

2008-12-01

310

Quantitative examination of a novel clustering method using magnetic resonance diffusion tensor tractography.  

PubMed

MR diffusion tensor imaging (DTI) can measure and visualize organization of white matter fibre tracts in vivo. DTI is a relatively new imaging technique, and new tools developed for quantifying fibre tracts require evaluation. The purpose of this study was to compare the reliability of a novel clustering approach with a multiple region of interest (MROI) approach in both healthy and disease (schizophrenia) populations. DTI images were acquired in 20 participants (n=10 patients with schizophrenia: 56+/-15 years; n=10 controls: 51+/-20 years) (1.5 T GE system) with diffusion gradients applied in 23 non-collinear directions, repeated three times. Whole brain seeding and creation of fibre tracts were then performed. Interrater reliability of the clustering approach, and the MROI approach, were each evaluated and the methods compared. There was high spatial (voxel-based) agreement within and between the clustering and MROI methods. Fractional anisotropy, trace, and radial and axial diffusivity values showed high intraclass correlation (p<0.001 for all tracts) for each approach. Differences in scalar indices of diffusion between the clustering and MROI approach were minimal. The excellent interrater reliability of the clustering method and high agreement with the MROI method, quantitatively and spatially, indicates that the clustering method can be used with confidence. The clustering method avoids biases of ROI drawing and placement, and, not limited by a priori predictions, may be a more robust and efficient way to identify and measure white matter tracts of interest. PMID:19159690

Voineskos, Aristotle N; O'Donnell, Lauren J; Lobaugh, Nancy J; Markant, Doug; Ameis, Stephanie H; Niethammer, Marc; Mulsant, Benoit H; Pollock, Bruce G; Kennedy, James L; Westin, Carl Fredrik; Shenton, Martha E

2008-12-29

311

Quantitative Examination of a Novel Clustering Method using Magnetic Resonance Diffusion Tensor Tractography  

PubMed Central

MR diffusion tensor imaging (DTI) can measure and visualize organization of white matter fibre tracts in vivo. DTI is a relatively new imaging technique, and new tools developed for quantifying fibre tracts require evaluation. The purpose of this study was to compare the reliability of a novel clustering approach with a multiple region of interest (MROI) approach in both healthy and disease (schizophrenia) populations. DTI images were acquired in 20 participants (n=10 patients with schizophrenia: 56 ± 15 years; n=10 controls: 51 ± 20 years) (1.5 Tesla GE system) with diffusion gradients applied in 23 non-collinear directions, repeated three times. Whole brain seeding and creation of fibre tracts were then performed. Interrater reliability of the clustering approach, and the MROI approach, were each evaluated and the methods compared. There was high spatial (voxel-based) agreement within and between the clustering and MROI methods. Fractional anisotropy, trace, and radial and axial diffusivity values showed high intraclass correlation (p<0.001 for all tracts) for each approach. Differences in scalar indices of diffusion between the clustering and MROI approach were minimal. The excellent interrater reliability of the clustering method and high agreement with the MROI method, quantitatively and spatially, indicates that the clustering method can be used with confidence. The clustering method avoids biases of ROI drawing and placement, and, not limited by a priori predictions, may be a more robust and efficient way to identify and measure white matter tracts of interest.

Voineskos, Aristotle N; O'Donnell, Lauren J; Lobaugh, Nancy J; Markant, Doug; Ameis, Stephanie H; Niethammer, Marc; Mulsant, Benoit H; Pollock, Bruce G; Kennedy, James L; Westin, Carl Fredrik; Shenton, Martha E

2009-01-01

312

A quantitative assessment of the hardenability increase resulting from a superhardenability treatment  

NASA Astrophysics Data System (ADS)

The superhardenability treatment, which consists of superheating steel melts to which fairly large aluminum additions have been made, has been studied in a wide range of low-alloy steels. By hardenability testing and dilatometry, it is shown that the treatment results in large and repeat-able hardenability increases due to a strong retardation of the ferrite/pearlite and bainite reactions. Superhardenability multiplying factors and equations which relate the ideal critical diameter of a superhardenable steel to its chemical content have been produced by using a combination of three hardenability tests. A mechanism for the superhardenability effect is proposed on the basis of the experimental finding that high austenitizing temperatures result in a loss of superhardenability.

Mostert, R. J.; van Rooyen, G. T.

1984-12-01

313

Quantitative assessment of port-wine stains using chromametry: preliminary results  

NASA Astrophysics Data System (ADS)

Objective assessment of the efficacy of different lasers for the treatment of port wine stains remains difficult. Chromametry gives reproducible information on the color of PWS, but its data are useless for a medical doctor. Thus a specific software was developed to allow graphic representation of PWS characteristics. Before the first laser treatment and after every treatment, tests were done using a chromameter on a marked zone of the PWS and on the control-lateral normal zone which represents the reference. The software calculates and represents graphically the difference of color between PWS and normal skin using data provided by the chromameter. Three parameters are calculated: (Delta) H is the difference of hue, (Delta) L is the difference of lightness and (Delta) E is the total difference of color. Each measured zone is represented by its coordinates. Calculated initial values were compared with the subjective initial color assessed by the dermatologist. The variation of the color difference was calculated using the successive values of (Delta) E after n treatments and was compared with the subjective classification of fading. Since January 1995, forty three locations have been measured before laser treatment. Purple PWS tended to differentiate from others but red and dark pink PWS could not be differentiated. The evolution of the color after treatment was calculated in 29 PWS treated 3 or 4 times. Poor result corresponded to an increase of (Delta) E. Fair and good results were associated to a decrease of (Delta) E. We did not observe excellent results during this study. These promising preliminary results need to be confirmed in a larger group of patients.

Beacco, Claire; Brunetaud, Jean Marc; Rotteleur, Guy; Steen, D.; Brunet, F.

1996-12-01

314

A CERIF data model extension for evaluation and quantitative expression of scientific research results  

Microsoft Academic Search

This paper presents a proposal of CERIF data model extension for evaluation of scientific research results. The data model\\u000a extension is based on the CERIF semantic layer which enables classification of entities and relations between entities according\\u000a to some classification scheme. The proposed data model was created using PowerDesigner CASE tool. The model is represented\\u000a using a physical data model

Dragan Ivanovic; Dusan Surla; Milos Rackovic

2011-01-01

315

Modified Method for Competitive Reverse Transcription Polymerase Chain Reaction for Rapid and Automated Quantitation of Messenger RNA in Multiple Samples.  

PubMed

Background: Competitive reverse transcription polymerase chain reaction (RT-PCR) has been used increasingly to quantitate messenger RNA (mRNA) levels; however, conventional competitive RT-PCR methods require four or five reactions per sample of RNA, employing serial dilutions of an internal competitor sequence, making analysis of multiple samples of tedious process. A modified method is described by which multiple samples and multiple RNA transcripts can be analyzed easily by an automated process. Methods and Results: Transforming growth factor beta-1 (TGF-beta-1) mRNA was assayed in total RNA extracted from cultured human skin fibroblasts. A standard solution of total RNA was first prepared by pooling RNA from several cell lines and stored in aliquots. A 270-bp competitor RNA molecule (RNA mimic) was prepared by in vitro transcription and was added to each reaction. PCR was performed with a fluorescent dye (Hex; Applied Biosystems, Foster City, CA)-labeled sense primer to amplify a 161-bp-long c DNA product of target TGF-beta-1 mRNA sequence and the RNA mimic. The PCR products were analyzed with an automated laser-scanned gel electrophoresis system and the area under the curve (AUC) was used for quantitation. The concentration TGF-beta-1 mRNA in standard RNA was determined by conventional competitive RT-PCR. Subsequently, equal amounts of RNA mimic were mixed with four serial dilutions of standard RNA and 0.1 µg of sample total RNA for RT-PCR. A standard curve was generated using the known dilutions of a standard target RNA solution and ratio of AUC for target to that for mimic for each dilution. The unknown sample was then quantitated by interpolation of its area under the curve ratio on the standard curve. This method had inter- and intra-assay coefficients of variation of less than 10%. Conclusions: This modification is highly reproducible for quantitation of mRNA and significantly reduces the number of PCR reactions required for each assay. It can be used to assay several RNA molecules in a given sample by designing RNA mimics and PCR primers to generate PCR products of different lengths so that they can be analyzed by the laser scanning of a single lane of electrophoretic gel. PMID:10462615

Vats; Katayama; Kim; Mauer; Fish; McGLENNEN

1997-12-01

316

Problems of a thermionic space NPS reactor unit quantitative reliability assessment on the basis of ground development results  

SciTech Connect

The paper sets forth major problems that arose in the course of a quantitative assessment of reliability of a TOPAZ-2 space NPS reactor unit performed on the basis of ground development results. Proposals are made on the possible ways to solve those problems through development and introduction of individual standards especially for the ground development stage, which would specify the assessment algorithm and censoring rules, and exclude a number of existing uncertainties when making a decision on going to flight testing. {copyright} {ital 1997 American Institute of Physics.}

Ponomarev-Stepnoi, N.N.; Nechaev, Y.A.; Khazanovich, I.M.; Samodelov, V.N. [RRC Kurchatov Institute Moscow123182 (Russia); Pavlov, K.A. [Russian Federation Ministry of Defense Central Scientific-Research Institute of Space Force MoscowK-160 (Russia)

1997-01-01

317

LC/ESI/MS method for the quantitative detection of guazatine residues in cereals.  

PubMed

Guazatine is a fungicide used in agriculture to control a wide range of seed-borne diseases of cereals and other vegetable foods. In this work, a LC-ESI-MS method was developed for the quantitative detection of guazatine residues in maize and hard wheat. Quantitative data were determined for the residues of the main diamines, triamines, and tetramines that cover more than 87% of the total contents of the mixture. The mean recoveries from the fortified cereals at 0.050 mg/kg ranged from 81 to 86%, with the coefficients of variation (CVs) ranging from 0.9 to 5.5% (n = 5). At 0.025 mg/kg, the recoveries ranged from 78 to 87%, with the CVs ranging from 0.8 to 6.3% (n = 5). The limits of quantification have been estimated to be 0.010, 0.004, 0.002, 0.002, 0.005, and 0.002 mg/kg, respectively, for GN, GG, GNG, GGN, GGG, and GGGG in maize and hard wheat (S/N ratio >10). PMID:17650002

Dreassi, Elena; Zizzari, Alessandra Tania; Zanfini, Assunta; Corbini, Gianfranco; Botta, Maurizio

2007-07-25

318

Method for quantitative analysis of glycosaminoglycan distribution in cultured natural and engineered cartilage.  

PubMed

Cartilage tissue engineering can provide a valuable tool for controlled studies of tissue development. As an example, analysis of the spatial distribution of glycosaminoglycans (GAG) in sections of cartilaginous tissues engineered under different culture conditions could be used to correlate the effects of environmental factors with the structure of the regenerated tissue. In this paper we describe a computer-based technique for quantitative analysis of safranin-O stained histological sections, using low magnification light microscopy images. We identified a parameter to quantify the intensity of red color in the sections, which in turn was proportional to the biochemically determined wet weight fraction of GAG in corresponding tissue samples, and to describe the spatial distribution of GAG as a function of depth from the section edge. A broken line regression model was then used to determine the thickness of an external region, with lower GAG fractions, and the spatial rate of change in GAG content. The method was applied to the quantitation of GAG distribution in samples of natural and engineered cartilage, cultured for 6 weeks in three different vessels: static flasks, mixed flasks, and rotating bioreactors. PMID:10548335

Martin, I; Obradovic, B; Freed, L E; Vunjak-Novakovic, G

319

Characterization of a method for quantitating food consumption for mutation assays in Drosophila  

SciTech Connect

Quantitation of food consumption is necessary when determining mutation responses to multiple chemical exposures in the sex-linked recessive lethal assay in Drosophila. One method proposed for quantitating food consumption by Drosophila is to measure the incorporation of 14C-leucine into the flies during the feeding period. Three sources of variation in the technique of Thompson and Reeder have been identified and characterized. First, the amount of food consumed by individual flies differed by almost 30% in a 24 hr feeding period. Second, the variability from vial to vial (each containing multiple flies) was around 15%. Finally, the amount of food consumed in identical feeding experiments performed over the course of 1 year varied nearly 2-fold. The use of chemical consumption values in place of exposure levels provided a better means of expressing the combined mutagenic response. In addition, the kinetics of food consumption over a 3 day feeding period for exposures to cyclophosphamide which produce lethality were compared to non-lethal exposures. Extensive characterization of lethality induced by exposures to cyclophosphamide demonstrate that the lethality is most likely due to starvation, not chemical toxicity.

Thompson, E.D.; Reeder, B.A.; Bruce, R.D. (Miami Valley Laboratories, Procter Gamble Company, Cincinnati, OH (USA))

1991-01-01

320

Tensile testing as a novel method for quantitatively evaluating bioabsorbable material degradation.  

PubMed

Bioabsorbable metallic materials have become a topic of interest in the field of interventional cardiology because of their potential application in stents. A well-defined, quantitative method for evaluating the degradation rate of candidate materials is currently needed in this area. In this study, biodegradation of 0.25-mm iron and magnesium wires was simulated in vitro through immersion in cell-culture medium with and without a fibrin coating (meant to imitate the neointima). The immersed samples were corroded under physiological conditions (37°C, 5% CO(2)). Iron degraded in a highly localized manner, producing voluminous corrosion product while magnesium degraded more uniformly. To estimate the degradation rate in a quantitative manner, both raw and corroded samples underwent tensile testing using a protocol similar to that used on polymeric nanofibers. The effective ultimate tensile stress (tensile stress holding constant cross-sectional area) was determined to be the mechanical metric that exhibited the smallest amount of variability. When the effective tensile stress data were aggregated, a statistically significant downward, linear trend in strength was observed in both materials (Fe and Mg) with and without the fibrin coating. It was also demonstrated that tensile testing is able to distinguish between the higher degradation rate of the bare wires and the lower degradation rate of the fibrin-coated wires with confidence. PMID:22847989

Bowen, Patrick K; Gelbaugh, Jesse A; Mercier, Phillip J; Goldman, Jeremy; Drelich, Jaroslaw

2012-07-30

321

Simple, Rapid and Inexpensive Quantitative Fluorescent PCR Method for Detection of Microdeletion and Microduplication Syndromes  

PubMed Central

Because of economic limitations, the cost-effective diagnosis of patients affected with rare microdeletion or microduplication syndromes is a challenge in developing countries. Here we report a sensitive, rapid, and affordable detection method that we have called Microdeletion/Microduplication Quantitative Fluorescent PCR (MQF-PCR). Our procedure is based on the finding of genomic regions with high homology to segments of the critical microdeletion/microduplication region. PCR amplification of both using the same primer pair, establishes competitive kinetics and relative quantification of amplicons, as happens in microsatellite-based Quantitative Fluorescence PCR. We used patients with two common microdeletion syndromes, the Williams-Beuren syndrome (7q11.23 microdeletion) and the 22q11.2 microdeletion syndromes and discovered that MQF-PCR could detect both with 100% sensitivity and 100% specificity. Additionally, we demonstrated that the same principle could be reliably used for detection of microduplication syndromes, by using patients with the Lubs (MECP2 duplication) syndrome and the 17q11.2 microduplication involving the NF1 gene. We propose that MQF-PCR is a useful procedure for laboratory confirmation of the clinical diagnosis of microdeletion/microduplication syndromes, ideally suited for use in developing countries, but having general applicability as well.

Stofanko, Martin; Goncalves-Dornelas, Higgor; Cunha, Pricila Silva; Pena, Heloisa B.; Vianna-Morgante, Angela M.; Pena, Sergio Danilo Junho

2013-01-01

322

Simple Absolute Quantification Method Correcting for Quantitative PCR Efficiency Variations for Microbial Community Samples  

PubMed Central

Real-time quantitative PCR (qPCR) is a widely used technique in microbial community analysis, allowing the quantification of the number of target genes in a community sample. Currently, the standard-curve (SC) method of absolute quantification is widely employed for these kinds of analysis. However, the SC method assumes that the amplification efficiency (E) is the same for both the standard and the sample target template. We analyzed 19 bacterial strains and nine environmental samples in qPCR assays, targeting the nifH and 16S rRNA genes. The E values of the qPCRs differed significantly, depending on the template. This has major implications for the quantification. If the sample and standard differ in their E values, quantification errors of up to orders of magnitude are possible. To address this problem, we propose and test the one-point calibration (OPC) method for absolute quantification. The OPC method corrects for differences in E and was derived from the ??CT method with correction for E, which is commonly used for relative quantification in gene expression studies. The SC and OPC methods were compared by quantifying artificial template mixtures from Geobacter sulfurreducens (DSM 12127) and Nostoc commune (Culture Collection of Algae and Protozoa [CCAP] 1453/33), which differ in their E values. While the SC method deviated from the expected nifH gene copy number by 3- to 5-fold, the OPC method quantified the template mixtures with high accuracy. Moreover, analyzing environmental samples, we show that even small differences in E between the standard and the sample can cause significant differences between the copy numbers calculated by the SC and the OPC methods.

Bodenhausen, Natacha; Zeyer, Josef; Burgmann, Helmut

2012-01-01

323

Advances in Statistical Methods to Map Quantitative Trait Loci in Outbred Populations  

PubMed Central

Statistical methods to map quantitative trait loci (QTL) in outbred populations are reviewed, extensions and applications to human and plant genetic data are indicated, and areas for further research are identified. Simple and computationally inexpensive methods include (multiple) linear regression of phenotype on marker genotypes and regression of squared phenotypic differences among relative pairs on estimated proportions of identity-by-descent at a locus. These methods are less suited for genetic parameter estimation in outbred populations but allow the determination of test statistic distributions via simulation or data permutation; however, further inferences including confidence intervals of QTL location require the use of Monte Carlo or bootstrap sampling techniques. A method which is intermediate in computational requirements is residual maximum likelihood (REML) with a covariance matrix of random QTL effects conditional on information from multiple linked markers. Testing for the number of QTLs on a chromosome is difficult in a classical framework. The computationally most demanding methods are maximum likelihood and Bayesian analysis, which take account of the distribution of multilocus marker-QTL genotypes on a pedigree and permit investigators to fit different models of variation at the QTL. The Bayesian analysis includes the number of QTLs on a chromosome as an unknown.

Hoeschele, I.; Uimari, P.; Grignola, F. E.; Zhang, Q.; Gage, K. M.

1997-01-01

324

Evaluation of Two Complementary Methods for Quantitative Profiling of PSA N-Glycans and N-Glycopeptides  

PubMed Central

The analytical methods for the structural characterization of protein glycosylation in glycomics and glycoproteomics are gradually becoming more suitable for biological applications. Over the past 10 years there has been a concerted effort to increase the sensitivity, speed and automation of the analysis of more complex glycoprotein mixtures at the level of biologically relevant dynamic ranges. However, these promising analytical tools, which predominantly are mass spectrometry based, needs thorough comparison and validation, in particular when quantitation is required. As a part of the ABRF Glycoprotein Research Group (gPRG) Quantitative Glycoprotein Study, we have profiled the single N-glycosylation of two sources of human prostate specific antigen (PSA) using two different, but commonly used, analytical methods allowing us to compare their qualitative and quantitative performance: i) Quantitative site-specific analysis of enriched PSA N-glycopeptides and ii) quantitative global analysis of released and reduced PSA N-glycans. For both approaches porous graphitized carbon LC connected directly with ion trap MS/MS (CID) was used for analyte separation and detection, respectively, but with different MS polarity mode detection. Using label-free relative quantitation, the two analytical methods produced very similar PSA glycoprofiles considering their different nature. Of the 40-50 monosaccharide compositions detected from each PSA variant, mostly minor quantitative differences in the glycoprofiles produced by the two approaches were observed, enhancing the confidence of the analysis. The pros and cons of the two glycoprofiling approaches and the intended near-future improvements will be discussed.

Packer, Nicolle H.; Thaysen-Andersen, Morten

2013-01-01

325

A simple method of fetal and neonatal heart rate beat-to-beat variability quantitation: preliminary report.  

PubMed

Good base-line fetal and neonatal heart rate beat-to-beat variability appears to be a reassuring sign of well-being. Conversely, decreased base-line heart rate beat-to-beat variability during the latter part of the intrapartum period is often associated with neonatal acidosis and/or depression. A simple method of quantitation of the beat-to-beat neonatal heart rate is reported here. This method of variability quantitation (VQ) consists of a continuous integration and display of the baseline heart rate beat-to-beat variability on a scale of zero to four, expressed in beats per minute averaged over a one-minute period. Serial variability quantitation in 35 neonates with different clinical conditions appeared to demonstrate a good correlation between the variability quantitation and the outcome of the neonates. Further studies are planned for evaluating the method in the intrapartum period. PMID:851144

Modanlou, H D; Freeman, R K; Braly, P

1977-04-15

326

On Sharing Quantitative Trait GWAS Results in an Era of Multiple-omics Data and the Limits of Genomic Privacy  

PubMed Central

Recent advances in genome-scale, system-level measurements of quantitative phenotypes (transcriptome, metabolome, and proteome) promise to yield unprecedented biological insights. In this environment, broad dissemination of results from genome-wide association studies (GWASs) or deep-sequencing efforts is highly desirable. However, summary results from case-control studies (allele frequencies) have been withdrawn from public access because it has been shown that they can be used for inferring participation in a study if the individual's genotype is available. A natural question that follows is how much private information is contained in summary results from quantitative trait GWAS such as regression coefficients or p values. We show that regression coefficients for many SNPs can reveal the person's participation and for participants his or her phenotype with high accuracy. Our power calculations show that regression coefficients contain as much information on individuals as allele frequencies do, if the person's phenotype is rather extreme or if multiple phenotypes are available as has been increasingly facilitated by the use of multiple-omics data sets. These findings emphasize the need to devise a mechanism that allows data sharing that will facilitate scientific progress without sacrificing privacy protection.

Im, Hae Kyung; Gamazon, Eric R.; Nicolae, Dan L.; Cox, Nancy J.

2012-01-01

327

On sharing quantitative trait GWAS results in an era of multiple-omics data and the limits of genomic privacy.  

PubMed

Recent advances in genome-scale, system-level measurements of quantitative phenotypes (transcriptome, metabolome, and proteome) promise to yield unprecedented biological insights. In this environment, broad dissemination of results from genome-wide association studies (GWASs) or deep-sequencing efforts is highly desirable. However, summary results from case-control studies (allele frequencies) have been withdrawn from public access because it has been shown that they can be used for inferring participation in a study if the individual's genotype is available. A natural question that follows is how much private information is contained in summary results from quantitative trait GWAS such as regression coefficients or p values. We show that regression coefficients for many SNPs can reveal the person's participation and for participants his or her phenotype with high accuracy. Our power calculations show that regression coefficients contain as much information on individuals as allele frequencies do, if the person's phenotype is rather extreme or if multiple phenotypes are available as has been increasingly facilitated by the use of multiple-omics data sets. These findings emphasize the need to devise a mechanism that allows data sharing that will facilitate scientific progress without sacrificing privacy protection. PMID:22463877

Im, Hae Kyung; Gamazon, Eric R; Nicolae, Dan L; Cox, Nancy J

2012-03-28

328

Scorecards: a new method to prevent adverse drug events? Preliminary results from a clinical field study.  

PubMed

In the field of the detection and prevention of preventable ADEs, several methods have been explored to decrease the rate of ADEs due to monitoring errors. This paper describes an innovative method that aims at improving patient safety by increasing ADEs' awareness of healthcare professionals. To this end, ADE-scorecards that provide healthcare professionals with retrospective data about ADEs' causes and rates have been developed. In order to evaluate the impact of this method on the ADE rate, in-field clinical tests have been set up. Data were collected by both qualitative (semi-structured interviews) and quantitative methods (log analysis and ADE rate calculation). Preliminary results reveal that ADE-scorecards are well-accepted by most of the healthcare professionals who intend to use them as discussion supports and/or learning tools. Thus, ADE-scorecards seem to be a relevant method to improve patient safety by increasing ADE-awareness of healthcare professionals. PMID:21685629

Marcilly, Romaric; Hackl, Werner O; Luyckx, Michel; Ammenwerth, Elske

2011-01-01

329

Comparison of two methods for obtaining quantitative mass concentrations from aerosol time-of-flight mass spectrometry measurements.  

PubMed

Aerosol time-of-flight mass spectrometry (ATOFMS) measurements provide continuous information on the aerodynamic size and chemical composition of individual particles. In this work, we compare two approaches for converting unscaled ATOFMS measurements into quantitative particle mass concentrations using (1) reference mass concentrations from a co-located micro-orifice uniform deposit impactor (MOUDI) with an accurate estimate of instrument busy time and (2) reference number concentrations from a co-located aerodynamic particle sizer (APS). Aerodynamic-diameter-dependent scaling factors are used for both methods to account for particle transmission efficiencies through the ATOFMS inlet. Scaling with APS data retains the high-resolution characteristics of the ambient aerosol because the scaling functions are specific for each hourly time period and account for a maximum in the ATOFMS transmission efficiency curve for larger-sized particles. Scaled mass concentrations obtained from both methods are compared with co-located PM(2.5) measurements for evaluation purposes. When compared against mass concentrations from a beta attenuation monitor (BAM), the MOUDI-scaled ATOFMS mass concentrations show correlations of 0.79 at Fresno, and the APS-scaled results show correlations of 0.91 at Angiola. Applying composition-dependent density corrections leads to a slope of nearly 1 with 0 intercept between the APS-scaled absolute mass concentration values and BAM mass measurements. This paper provides details on the methodologies used to convert ATOFMS data into continuous, quantitative, and size-resolved mass concentrations that will ultimately be used to provide a quantitative estimate of the number and mass concentrations of particles from different sources. PMID:16944899

Qin, Xueying; Bhave, Prakash V; Prather, Kimberly A

2006-09-01

330

A new method for quantitative determination of tritium-labeled nucleoside kinase products adsorbed on DEAE-cellulose.  

PubMed

The counts of tritiated compounds--adsorbed to paper disks, paper chromatograms, electrophoretograms or TLC plates--can be strongly affected by extended self-absorption of tritium beta-particles on the matrix, due to their low energy. Therefore fully quantitative results can be obtained only by elution of the substances or decomposition of the matrix and subsequent counting in homogeneous solution. In this study we describe a new method for fast and proper decomposition of cellulose matrices by cellulase digestion prior to scintillation counting. This new approach yields up to 98% recovery. For method validation recombinant herpes simplex type 1 thymidine kinase was characterised kinetically. The Km of 0.2 microM remained the same as expected but Vmax was considerably higher yielding 1050 pmol/microgram/min. PMID:8769128

Gerber, S; Folkers, G

1996-08-01

331

Numbers and WordsCombining Quantitative and Qualitative Methods in a Single Large-Scale Evaluation Study  

Microsoft Academic Search

This article discusses how quantitative and qualitative methods can be combined in a single evaluation study to better understand the phenomenon in question. Three perspectives on combining methods are reviewed: the purist approach where the two methods are seen as mutually exclusive, the situationalist approach that views them as separate but equal, and the pragmatist approach that suggests integration is

Gretchen B. Rossman; Bruce L. Wilson

1985-01-01

332

Systems and methods for quantitatively characterizing slow wave activities and states in sleep  

US Patent & Trademark Office Database

A method for quantitative sleep characterization includes acquiring a surface electroencephologram (surf-EEG) signal from an individual by a probe, decomposing the surf-EEG signal into a plurality of intrinsic mode functions (IMFs) by a computer processor in communication with the probe, wherein the plurality of IMFs comprises a first group of IMFs and a second group of IMFs, calculating a ratio comprising an amplitude or power of at least one of the IMFs in the first group in the numerator and a corresponding amplitude or power of at least one of the IMFs in the second group in the denominator; and identifying a period in the surf-EEG waveform as slow wave sleep (SWS) if the ratio associated with the period is above a predetermined threshold.

2012-10-02

333

A quantitative magnetic analytical method using Curie's law for a mixture of paramagnetic and diamagnetic substances  

NASA Astrophysics Data System (ADS)

The principle of quantitative magnetic analytical measurement using Curie's law is proposed as a future candidate for a new potential primary direct method of measurement for amount of substance. The targeted main analyte in a mixture sample is a species—a rare-earth ion or a transition-metal ion—that has a free quantum spin. The matrix of the mixture sample is diamagnetic. The spin number of the analyte can be obtained from the temperature dependence of the sample's magnetic moment. This analytical method uses differences in the temperature dependences of Langevin paramagnetism, which obeys Curie's law, and diamagnetism, which exhibits temperature-independent behaviour. For preliminary validation of this analytical method, powder mixture samples of gadolinium oxide in silicon oxide were prepared by a gravimetric blending method. The mass fractions of the prepared mixture samples were approximately 0.2 to 0.008. The values of the samples' magnetic moments at temperatures below 340 K were measured using a superconducting quantum interference device magnetometer. Each analytical concentration of gadolinium oxide determined by the temperature dependence of the magnetic moment was found to be consistent with the gravimetric concentration within a relative difference of approximately 10%.

Matsumoto, Nobuhiro; Kato, Kenji

2012-08-01

334

Some methods of obtaining quantitative structure-activity relationships for quantities of environmental interest  

SciTech Connect

Methods are described for obtaining quantitative structure-activity relationships (QSAR) for the estimation of quantities of environmental interest. Toxicities of alkylamines and of alkyl alkanoates are well correlated by the alkyl bioactivity branching equation (ABB). Narcotic activities of 1,1-disubstituted ethylenes are correlated by the intermolecular forces bioactivity (IMF) equation. When the data set has a limited number of substituents in equivalent positions the group number (GN) equation, derivable from the IMF equation, can be used for correlation. It has been successfully applied to aqueous solubilities, 1-octanol-water partition coefficients, and bioaccumulation factors and ecological magnifications for organochlorine compounds. A combination of the omega method for combining data sets for different organisms with the GN equation has been used to correlate toxicities of organochlorine insecticides in two species of fish. Toxicities of carbamates have been correlated by a combination of the zeta method and the IMFB equation. The ABB and the GN equations are particularly useful in that they generally do not require parameter tables, and that the parameters they use are error-free. The methods presented here, as shown by the examples given, should make it possible to establish a collection of QSAR for toxicities, bioaccumulation factors, aqueous solubilities, partition coefficients, and other properties of sets of compounds of environmental interest. 29 references.

Charton, M.

1985-09-01

335

Comparison of quantitative spectral similarity analysis methods for protein higher-order structure confirmation.  

PubMed

Optical and vibrational spectroscopic techniques are important tools for evaluating secondary and tertiary structures of proteins. These spectroscopic techniques are routinely applied in biopharmaceutical development to elucidate structural characteristics of protein products, to evaluate the impact of processing and storage conditions on product quality, and to assess comparability of a protein product before and after manufacturing changes. Conventionally, the degree of similarity between two spectra has been determined visually. In addition to requiring a significant amount of analyst training and experience, visual inspection of spectra is inherently subjective, and any determination of comparability based on visual analysis of spectra is therefore arbitrary. Here, we discuss a general methodology for evaluating the suitability of numerical methods to calculate spectral similarity, and then we apply the methodology to compare four quantitative spectral similarity methods: the correlation coefficient, area of spectral overlap, derivative correlation algorithm, and spectral difference methods. While the most effective spectral similarity method may depend on the particular application, all four approaches are superior to visual evaluation, and each is suitable for assessing the degree of similarity between spectra. PMID:23219560

Teska, Brandon M; Li, Cynthia; Winn, Bradley C; Arthur, Kelly K; Jiang, Yijia; Gabrielson, John P

2012-12-03

336

Quantitative calcium resistivity based method for accurate and scalable water vapor transmission rate measurement  

NASA Astrophysics Data System (ADS)

The development of flexible organic light emitting diode displays and flexible thin film photovoltaic devices is dependent on the use of flexible, low-cost, optically transparent and durable barriers to moisture and/or oxygen. It is estimated that this will require high moisture barriers with water vapor transmission rates (WVTR) between 10-4 and 10-6 g/m2/day. Thus there is a need to develop a relatively fast, low-cost, and quantitative method to evaluate such low permeation rates. Here, we demonstrate a method where the resistance changes of patterned Ca films, upon reaction with moisture, enable one to calculate a WVTR between 10 and 10-6 g/m2/day or better. Samples are configured with variable aperture size such that the sensitivity and/or measurement time of the experiment can be controlled. The samples are connected to a data acquisition system by means of individual signal cables permitting samples to be tested under a variety of conditions in multiple environmental chambers. An edge card connector is used to connect samples to the measurement wires enabling easy switching of samples in and out of test. This measurement method can be conducted with as little as 1 h of labor time per sample. Furthermore, multiple samples can be measured in parallel, making this an inexpensive and high volume method for measuring high moisture barriers.

Reese, Matthew O.; Dameron, Arrelaine A.; Kempe, Michael D.

2011-08-01

337

Some methods of obtaining quantitative structure-activity relationships for quantities of environmental interest.  

PubMed Central

Methods are described for obtaining quantitative structure-activity relationships (QSAR) for the estimation of quantities of environmental interest. Toxicities of alkylamines and of alkyl alkanoates are well correlated by the alkyl bioactivity branching equation (ABB). Narcotic activities of 1,1-disubstituted ethylenes are correlated by the intermolecular forces bioactivity (IMF) equation. When the data set has a limited number of substituents in equivalent positions the group number (GN) equation, derivable from the IMF equation, can be used for correlation. It has been successfully applied to aqueous solubilities, 1-octanol-water partition coefficients, and bioaccumulation factors and ecological magnifications for organochlorine compounds. A combination of the omega method for combining data sets for different organisms with the GN equation has been used to correlate toxicities of organochlorine insecticides in two species of fish. Toxicities of carbamates have been correlated by a combination of the zeta method and the IMFB equation. The ABB and the GN equations are particularly useful in that they generally do not require parameter tables, and that the parameters they use are error-free. The methods presented here, as shown by the examples given, should make it possible to establish a collection of QSAR for toxicities, bioaccumulation factors, aqueous solubilities, partition coefficients, and other properties of sets of compounds of environmental interest.

Charton, M

1985-01-01

338

Cerenkov radiation imaging as a method for quantitative measurements of beta particles in a microfluidic chip  

NASA Astrophysics Data System (ADS)

It has been observed that microfluidic chips used for synthesizing 18F-labeled compounds demonstrate visible light emission without nearby scintillators or fluorescent materials. The origin of the light was investigated and found to be consistent with the emission characteristics from Cerenkov radiation. Since 18F decays through the emission of high-energy positrons, the energy threshold for beta particles, i.e. electrons or positrons, to generate Cerenkov radiation was calculated for water and polydimethylsiloxane (PDMS), the most commonly used polymer-based material for microfluidic chips. Beta particles emitted from 18F have a continuous energy spectrum, with a maximum energy that exceeds this energy threshold for both water and PDMS. In addition, the spectral characteristics of the emitted light from 18F in distilled water were also measured, yielding a broad distribution from 300 nm to 700 nm, with higher intensity at shorter wavelengths. A photograph of the 18F solution showed a bluish-white light emitted from the solution, further suggesting Cerenkov radiation. In this study, the feasibility of using this Cerenkov light emission as a method for quantitative measurements of the radioactivity within the microfluidic chip in situ was evaluated. A detector previously developed for imaging microfluidic platforms was used. The detector consisted of a charge-coupled device (CCD) optically coupled to a lens. The system spatial resolution, minimum detectable activity and dynamic range were evaluated. In addition, the calibration of a Cerenkov signal versus activity concentration in the microfluidic chip was determined. This novel method of Cerenkov radiation measurements will provide researchers with a simple yet robust quantitative imaging tool for microfluidic applications utilizing beta particles.

Cho, Jennifer S.; Taschereau, Richard; Olma, Sebastian; Liu, Kan; Chen, Yi-Chun; K-F Shen, Clifton; van Dam, R. Michael; Chatziioannou, Arion F.

2009-11-01

339

Rapid method for the quantitative determination of efavirenz in human plasma.  

PubMed

A pharmacokinetic interaction study between efavirenz (EFV), a non-nucleoside reverse transcriptase inhibitor used in the treatment of HIV-1 infection, and an African traditional medicine, African potato in human subjects was undertaken. This necessitated the development and validation of a quantitative method for the analysis of EFV in plasma. A simple mobile phase consisting of 0.1M formic acid, acetonitrile and methanol (43:52:5) was pumped at a low flow rate of 0.3 ml/min through a reverse phase Phenomenex Luna C(18) (2) (5 microm, 150 mm x 2.0mm i.d.) column maintained at 40 degrees C. Diclofenac sodium was used as an internal standard (IS) and EFV and IS were monitored at 247 nm and 275 nm, respectively. A simple and rapid sample preparation involved the addition of mobile phase to 100 microl of plasma to precipitate plasma proteins followed by direct injection of 10 microl of supernatant onto the column. The procedures were validated according to international standards with good reproducibility and linear response (r=0.9990). The intra- and inter-day accuracies were between 12.3 and 17.7% at the LLOQ and between -5.8 and 9.1% for the QC samples. The intra- and inter-day precision of EFV determinations were 5.1 or less and 7.2% RSD or less, respectively across the entire QC concentration range. Mean recovery based on high, medium and low quality control standards ranged between 92.7 and 94.1% with %RSD values better than 3%. Plasma samples were evaluated for short-term (ambient temperature for 6h) and long-term (-10+/-2 degrees C for 60 days) storage conditions and were found to be stable. The method described is cost-effective and has the necessary accuracy and precision for the rapid quantitative determination of EFV in human plasma. PMID:19375262

Mogatle, Seloi; Kanfer, Isadore

2009-03-20

340

Commentary to Gebel 2012: A quantitative review should apply meta-analytical methods-and this applies also to quantitative toxicological reviews.  

PubMed

Gebel (In Arch Toxicol 87(5):923-924, 2013) replied to my Letter to the Editor (Morfeld in Arch Toxicol 87(5):921, 2013) in which I criticized the quantitative review of inhalation rat studies on the association of granular biopersistent dust exposures and lung cancer risk (Gebel in Arch Toxicol 86(7):995-1007, 2012). My methodological comments were not understood. The Editors of the Archives invited me to detail and substantiate my criticism. The main issues are as follows: (1) A quantitative summary of the study results was performed without weighting for precision of the single studies (the published unweighted synthesis is potentially biased). (2) No heterogeneity assessment was performed before combining the findings (it is unclear whether overall summaries are sensible). (3) Correlation coefficients were used (correlations are distorted estimates of exposure-response and misleading). (4) An incomplete input data table was published (no transparent reporting, no replication possible for the reader). The quantitative synthesis by Gebel (In Arch Toxicol 86(7):995-1007, 2012) does not fulfil the usual requirements of a scientific quantitative review and should be replaced by an appropriate meta-analysis. PMID:24068040

Morfeld, Peter

2013-09-26

341

Quantitative computed tomography of vertebral spongiosa: a sensitive method for detecting early bone loss after oophorectomy  

SciTech Connect

The bone mineral loss was assessed serially in 37 premenopausal women for 24 months after oophorectomy and the dose-response for conjugated estrogen therapy in preventing this loss was determined. Spinal cancellous bone was measured by quantitative computed tomography and measurement of appendicular cortical bone by radial photon absorptiometry and metacarpal radiogrammetry. For the placebo and low-dose treatment groups, the mean annual bone mineral losses were 7% to 9% from the vertebral spongiosum and 1% to 3% from the peripheral cortex. The correlation between axial and appendicular loss was weak, precluding a reliable estimate of spinal loss from peripheral measurements. For the maximal-dose group (0.6 mg/d), the mean annual bone mineral losses were less than 0.5% from the axial and appendicular sites, and were not significant. The results indicate that spinal quantitative computed tomography provides a highly sensitive measurement of bone mineral loss after oophorectomy, that bone mineral loss is five- to sevenfold greater from the spinal spongiosum than from the appendicular cortex, and that conjugated estrogen in doses of less than 0.6 mg/d are inadequate to prevent the vertebral mineral loss.

Genant, H.K.; Cann, C.E.; Ettinger, B.; Gordan, G.S.

1982-11-01

342

Towards microfluorometric quantitation of polyamines in situ. Relationship between cellular polyamine concentration and fluorescence yield of the formaldehyde fluorescamine method.  

PubMed

Two different fluorescence cytochemical methods, the formaldehyde-fluorescamine (FF) method and the orthophthalaldehyde (OPT) method as well as an immunocytochemical method have been developed for the localization of spermidine and spermine. Of these three methods, the FF-method is the most easy to perform. We have studied the relationship between fluorescence intensity induced by the FF-method and cellular polyamine levels measured by HPLC in MCF-7 cells and HeLa cells. The experiments were designed to obtain different cell concentrations of polyamines. Cells grown on microscope slides in Petri-dishes were partly depleted of spermidine by two days inhibition of their ornithine decarboxylase activity using alpha-difluoromethylornithine. One hr before harvest the cells were exposed to different concentrations (0-30 microM) of spermidine. Microfluorometric results and chemical determinations of spermidine and spermine were obtained from each separate slide. The cellular total polyamine (spermidine + spermine) concentration on the slides varied between 4 and 15 nmol per mg protein (MCF-7 cells) and 5 and 26 nmol per mg protein (HeLa cells) and the corresponding microfluorometric results between 60 and 115 arbitrary units (MCF-7 cells) and 80 and 160 arbitrary units (HeLa cells). Simple regression analysis showed a good linear relationship between cellular polyamine concentration and FF-fluorescence yield. The correlation coefficient for MCF-7 cells was 0.86 and for HeLa cells 0.82, significance of the correlations was p less than or equal to 0.0001. Our results add further credence to the specificity of the FF-method and indicate that the method may be useful for microfluorometric quantitation of polyamines in situ. PMID:2323952

Hougaard, D M; Larsson, L I

1990-01-01

343

Evaluating Multiple Prevention Programs: Methods, Results, and Lessons Learned  

ERIC Educational Resources Information Center

|Extension faculty and agents/educators are increasingly collaborating with local and state agencies to provide and evaluate multiple, distinct programs, yet there is limited information about measuring outcomes and combining results across similar program types. This article explicates the methods and outcomes of a state-level evaluation of…

Adler-Baeder, Francesca; Kerpelman, Jennifer; Griffin, Melody M.; Schramm, David G.

2010-01-01

344

Evaluation of a Rapid, Quantitative Real-Time PCR Method for Enumeration of Pathogenic Candida Cells in Water  

PubMed Central

Quantitative PCR (QPCR) technology, incorporating fluorigenic 5? nuclease (TaqMan) chemistry, was utilized for the specific detection and quantification of six pathogenic species of Candida (C. albicans, C. tropicalis, C. krusei, C. parapsilosis, C. glabrata and C. lusitaniae) in water. Known numbers of target cells were added to distilled and tap water samples, filtered, and disrupted directly on the membranes for recovery of DNA for QPCR analysis. The assay's sensitivities were between one and three cells per filter. The accuracy of the cell estimates was between 50 and 200% of their true value (95% confidence level). In similar tests with surface water samples, the presence of PCR inhibitory compounds necessitated further purification and/or dilution of the DNA extracts, with resultant reductions in sensitivity but generally not in quantitative accuracy. Analyses of a series of freshwater samples collected from a recreational beach showed positive correlations between the QPCR results and colony counts of the corresponding target species. Positive correlations were also seen between the cell quantities of the target Candida species detected in these analyses and colony counts of Enterococcus organisms. With a combined sample processing and analysis time of less than 4 h, this method shows great promise as a tool for rapidly assessing potential exposures to waterborne pathogenic Candida species from drinking and recreational waters and may have applications in the detection of fecal pollution.

Brinkman, Nichole E.; Haugland, Richard A.; Wymer, Larry J.; Byappanahalli, Muruleedhara; Whitman, Richard L.; Vesper, Stephen J.

2003-01-01

345

Advanced bibliometric methods as quantitative core of peer review based evaluation and foresight exercises  

Microsoft Academic Search

This paper gives an overview of the potentials and limitations of bibliometric methods for the assessment of strengths and weaknesses in research performance, and for monitoring scientific developments. We distinguish two different methods. In the first application, research performance assessment, the bibliometric method is based on advanced analysis of publication and citation data. We show that the resulting indicators are

A. F. J. van Raan

1996-01-01

346

Quantitative methods for structural characterization of proteins based on deep UV resonance Raman spectroscopy.  

PubMed

Here we report on novel quantitative approaches for protein structural characterization using deep UV resonance Raman (DUVRR) spectroscopy. Specifically, we propose a new method combining hydrogen-deuterium (HD) exchange and Bayesian source separation for extracting the DUVRR signatures of various structural elements of aggregated proteins including the cross-beta core and unordered parts of amyloid fibrils. The proposed method is demonstrated using the set of DUVRR spectra of hen egg white lysozyme acquired at various stages of HD exchange. Prior information about the concentration matrix and the spectral features of the individual components was incorporated into the Bayesian equation to eliminate the ill-conditioning of the problem caused by 100% correlation of the concentration profiles of protonated and deuterated species. Secondary structure fractions obtained by partial least squares (PLS) and least squares support vector machines (LS-SVMs) were used as the initial guess for the Bayessian source separation. Advantages of the PLS and LS-SVMs methods over the classical least squares calibration (CLSC) are discussed and illustrated using the DUVRR data of the prion protein in its native and aggregated forms. PMID:20580825

Shashilov, Victor A; Sikirzhytski, Vitali; Popova, Ludmila A; Lednev, Igor K

2010-05-24

347

A quick method for computing approximate thresholds for quantitative trait loci detection.  

PubMed Central

This article proposes a quick method for computing approximate threshold levels that control the genome-wise type I error rate of tests for quantitative trait locus (QTL) detection in interval mapping (IM) and composite interval mapping (CIM). The procedure is completely general, allowing any population structure to be handled, e.g., BC(1), advanced backcross, F(2), and advanced intercross lines. Its main advantage is applicability in complex situations where no closed form approximate thresholds are available. Extensive simulations demonstrate that the method works well over a range of situations. Moreover, the method is computationally inexpensive and may thus be used as an alternative to permutation procedures. For given values of the likelihood-ratio (LR)-profile, computations involve just a few seconds on a Pentium PC. Computations are simple to perform, requiring only the values of the LR statistics (or LOD scores) of a QTL scan across the genome as input. For CIM, the window size and the position of cofactors are also needed. For the approximation to work well, it is suggested that scans be performed with a relatively small step size between 1 and 2 cM.

Piepho, H P

2001-01-01

348

Quantitative study of renormalization transformation method to correct the inhomogeneity in MR images  

NASA Astrophysics Data System (ADS)

The purpose of this work is to evaluate the effectiveness of using a newly proposed renormalization transformation (RT) technique to correct nonuniformity in MR images. Simulated brain T1, T2 and PD weighted images with two types of bias fields and Gaussian white noise were created using the average signal intensities of white matter, gray matter, and CSF from segmented masks of actual patient examinations. These images were then corrected by the RT method and quantitatively compared with the original non-biased simulated images. This study demonstrated that a single optimal correction exists for the RT method. At the optimal correction, the RT method can remove more than 75 percent of the bias field without significant loss of useful contrast in the images. Unfortunately, this optimal correction can not be directly determined for actual patient images where the truth is not known. However, simulated images showed that the optimal correction could be estimated from changes in the contrast ratio map, where the contrast ratio is the ratio of the local intensity standard deviation and local average intensity. Using the contrast ratio map, the optimal correction can be reliably applied in patient images.

Ji, Qing; Reddick, Wilburn E.; Glass, John O.; Krynetskiy, Evgeny

2002-05-01

349

“Do I need research skills in working life?”: University students’ motivation and difficulties in quantitative methods courses  

Microsoft Academic Search

This study explored university students’ views of whether they will need research skills in their future work in relation\\u000a to their approaches to learning, situational orientations on a learning situation of quantitative methods, and difficulties\\u000a experienced in quantitative research courses. Education and psychology students in both Finland (N = 46) and the USA (N = 122), who thought that they would need research skills

Mari Murtonen; Erkki Olkinuora; Päivi Tynjälä; Erno Lehtinen

2008-01-01

350

Semi-quantitative determination of the modes of occurrence of elements in coal: Results from an International Round Robin Project  

SciTech Connect

Quantifying the modes of occurrence of elements in coal is necessary for the development of models to predict an element's behavior during in-ground leaching, weathering, coal cleaning, and combustion. Anticipating the behavior of the trace elements is necessary for evaluating the environmental and human health impacts, technological impacts, and economic byproduct potential of coal use. To achieve the goal of quantifying element modes of occurrence, an international round robin project was initiated. Four bituminous coal samples (from the United States, England, Australia and Canada) were distributed to participating laboratories (9 labs from 5 countries) for analysis. Preliminary results indicate that there is good agreement among six laboratories for the chemical analyses. Using selective leaching, quantitative electron microprobe analyses, and semi-quantitative X-ray diffraction, the authors found that many elements have similar modes of occurrence in all four samples. For example, at least 75% of the Al, K, and Li and about 50% of Be, Sc, V, and Cr are leached by HF. Because HF dissolves silicates, the authors infer that these elements are in the clays. As, Hg, Cu, Zn, Cd, and Pb are leached primarily by HCl and HNO{sub 3}, indicating that they are associated with mono- (such as sphalerite and galena) and di-sulfides (pyrite). Leaching results indicate that small amounts of these metals may be associated with clays and organics. Iron behaves differently in each three of the samples, likely due to different proportions of iron in sulfide, carbonate, and silicate phases. Results from the other laboratories (using selective leaching and density separations) appear to be consistent with these results.

Willett, J.C.; Finkelman, R.B.; Mroczkowski, S.J.; Palmer, C.A.; Kolker, A.

1999-07-01

351

[A new qualitative and quantitative analytical method of chromatographic fingerprints: total quantum statistical moment].  

PubMed

A new qualitative and quantitative analytical method of the chromatographic fingerprints: the Total Quantum Statistical Moment (TQSM) has been eluciated and established according to statistical moment principle. The study was carried out with model drugs as the alcohol extracted liquid for Radix et Rhizoma Rhei (AELRR) by HPLC under the chromatographic conditions that the column was C18, 4.6 mm x 250 mm, 5 microm; the detection of wavelengths was set at 254 nm; a solution of acetonitrile: 1% acetic acid water (from 0:100 to 100:0) was carried with gradient elution as the mobile phase; the ratio of flow was 1 mL min(-1); the temperature was 40 degrees C. The coefficients were dealt with Excel document. It has been established the expressions that consists of four main parameters: 1) total quantum zero moment as AUC(T), area under curve; 2) total quantum respondent ratio as AUCPW(T), area under curve per weight; 3) total quantum center moment as MCRT(T), mean chromatographic retention time of total quantum, expressed by lambda(T); 4) total quantum variance as VCRT(T), variance of mean chromatographic retention time of total quantum, expressed by sigma2(T), by which we have obtained. The TQSM's parameters of the AELRR, such as AUC(T) as 3.273 x 10(8) microV s, AUCPW(T) as 2.286 x 10(6) microV s mg (-1), MCRT(T) as 33.50 min, VCRT(T) as 484.4 min2, and total quantum concentration as 143.2 mg mL(-1). The total quantum statistic moment can be characterized the curve of chromatographic fingerprints with expressive parameters above, also used to quantitative analyses by AUC(T), to qualitative analyses by AUCPW(T), MCR(T), and VCRT(T). PMID:18507349

He, Fu-Yuan; Zhou, Hong-Hao; Deng, Kai-Wen; Liu, Weng-Long; Liu, Ping-An

2008-02-01

352

A quantitative method for the characterisation of karst aquifers based on spring hydrograph analysis  

NASA Astrophysics Data System (ADS)

This paper presents a method for characterizing flow systems in karst aquifers by acquiring quantitative information about the geometric and hydraulic aquifer parameters from spring hydrograph analysis. Numerical sensitivity analyses identified two fundamentally different flow domains, depending on the overall configuration of aquifer parameters. These two domains have been quantitatively characterized by deducing analytical solutions for the global hydraulic response of simple two-dimensional model geometries. During the baseflow recession of mature karst systems, the hydraulic parameters of karst conduits do not influence the drainage of the low-permeability matrix. In this case the drainage process is influenced by the size and hydraulic parameters of the low-permeability blocks alone. This flow condition has been defined as matrix-restrained flow regime (MRFR). During the baseflow recession of early karst systems and fissured systems, as well as the flood recession of mature systems, the recession process depends on the hydraulic parameters and the size of the low-permeability blocks, conduit conductivity and the total extent of the aquifer. This flow condition has been defined as conduit-influenced flow regime (CIFR). Analytical formulae demonstrated the limitations of equivalent models. While equivalent discrete-continuum models of early karst systems may reflect their real hydraulic response, there is only one adequate parameter configuration for mature systems that yields appropriate recession coefficient. Consequently, equivalent discrete-continuum models are inadequate for simulating global response of mature karst systems. The recession coefficient of equivalent porous medium models corresponds to the transition between matrix-restrained and conduit-influenced flow. Consequently, equivalent porous medium models yield corrupted hydrographs both in mature and early systems, and this approach is basically inadequate for modelling global response of karst aquifers.

Kovács, Attila; Perrochet, Pierre; Király, László; Jeannin, Pierre-Yves

2005-03-01

353

A novel standard sample powder preparation method for quantitative analysis of polymorphs.  

PubMed

The purpose of this study was to improve the sensitivity and accuracy of the quantitative analysis of polymorphic mixtures. Calibration curve reliability has been improved through the advancement of standard mixture preparation techniques whereby samples at scales of several grams are homogeneously and accurately prepared without decrease in crystallinity. Crystalline powders are first micronized to anisotropic, nearly equal-sized (<10 microm) particles of almost random orientation in an air jet mill. These powders are then mixed in a vibration mill that includes rubber balls as mixing media. Using this technique, alpha and gamma forms of indomethacin (IMC) were prepared in various proportions from 0.5% to 50% alpha content and subjected to X-ray powder diffraction analysis. The validation data showed that these precisely prepared standard mixtures resulted in superior analytical sensitivity and accuracy compared to those prepared by agate mortar. PMID:15793799

Okumura, Takehiro; Otsuka, Makoto

2005-05-01

354

Quantitative chromosome map of Coix lacryma-jobi L. by imaging methods.  

PubMed

Prometaphase chromosomes of Coix lacryma-jobi L. were quantitatively analyzed based on their distribution patterns of DAPI signals. The DAPI signals showed prominent uneven distribution along the chromosomes. Based on the DAPI signal patterns, a quantitative chromosome map was constructed for the first time in C. lacryma-jobi. The quantitative chromosome map will offer the foundation for genome analysis of C. lacryma-jobi. PMID:14986433

Han, Yong-Hua; Qi, Cui-Ying; Liu, Li-Hua; Song, Yun-Chun

2003-12-01

355

COMPUTATIONAL STUDIES OF CLUSTERS:Methods and Results  

NASA Astrophysics Data System (ADS)

The experimental and computational study of clusters has been an active field of research for over a decade. This review provides an overview of some of the methods that have been developed to study clusters and some of the results that have been obtained. Included are computational approaches to explore the potential energy surface for clusters, methods to extract thermodynamic properties from the potential surface information and approaches to insure simulation studies are performed in an ergodic fashion. The methods have proved to be useful in studying the structural transition from clusters to bulk phases, phase changes in small clusters and the importance of quantum effects. The review ends with a discussion of problems in cluster chemistry and physics that are of interest for future investigations.

Freeman, David L.; Doll, J. D.

1996-10-01

356

A novel method for quantitative determination of tea polysaccharide by resonance light scattering  

NASA Astrophysics Data System (ADS)

A new method for the determination of tea polysaccharide (TPS) in green tea ( Camellia sinensis) leaves has been developed. The method was based on the enhancement of resonance light scattering (RLS) of TPS in the presence of cetylpyridinium chloride (CPC)-NaOH system. Under the optimum conditions, the RLS intensity of CPC was greatly enhanced by adding TPS. The maximum peak of the enhanced RLS spectra was located at 484.02 nm. The enhanced RLS intensity was proportional to the concentration of TPS in the range of 2.0-20 ?g/ml. It showed that the new method and phenol-sulfuric acid method give some equivalent results by measuring the standard compounds. The recoveries of the two methods were 96.39-103.7% (novel method) and 100.15-103.65% (phenol-sulfuric acid method), respectively. However, it showed that the two methods were different to some extent. The new method offered a limit of detection (LOD) of 0.047 ?g/ml, whereas the phenol-sulfuric acid method gives a LOD of 1.54 ?g/ml. Interfered experiment demonstrated that the new method had highly selectivity, and was more suitable for the determination of TPS than phenol-sulfuric method. Stability test showed that new method had good stability. Moreover, the proposed method owns the advantages of easy operation, rapidity and practicability, which suggested that the proposed method could be satisfactorily applied to the determination of TPS in green tea.

Wei, Xinlin; Xi, Xionggang; Wu, Muxia; Wang, Yuanfeng

2011-09-01

357

Method for processing wastes resulting from production of phosphorus  

SciTech Connect

The method comprises processing slime and off-gases resulting from the production of phosphorus with an aqueous solution of copper sulphate having a concentration of from 15 to 50% at a temperature within the range of from 20* to 80* C. As a result, two products are obtained, i.e., a liquid product and a solid one. The solid product containing mainly copper phosphide as well as fluorides and chlorides of alkali metals and silicon, and silicates of calcium and aluminum, is used as a modifying and refining agent for hypereutectic silumines and for the manufacture of a copper-phosphorus alloy. The liquid product containing phosphoric acid, sulphuric acid and copper sulphate is used as starting product for the preparation of a copper-containing fertilizer. The method according to the present invention makes it possible to modify the production of phosphorus so as to eliminate the formation of secondary wastes and improve the environmental control.

Alzhanov, T.M.; Bykov, V.I.; Chernogorenko, V.B.; Dmitrenko, V.V.; Ishkhanov, E.S.; Kipchakbaev, A.D.; Koverya, V.M.; Lynchak, K.A.; Markovsky, E.A.; Muchnik, S.V.; Pobortsev, M.E.; Sapian, V.G.; Sergienko, V.Y.; Vopilov, A.N.

1980-03-11

358

Quantitative Determination of Ciprofibrate in Tablets by Derivative UV Spectroscopy and RP-HPLC Method  

PubMed Central

A derivative UV spectrophotometric and a reversed phase high-performance liquid chromatographic method for the determination of ciprofibrate in tablets was developed. The first-order derivative UV spectrophotometric method was found to be accurate with 100.57±0.97 recovery and precise with a coefficient of variation of 1.44. These results were compared to those obtained by reference methods, zero-order UV spectrophotometric method and a reversed-phase high-performance liquid chromatography method. A reversed-phase C8 column with methanol:water (90:10, v/v, pH 3.7) mobile phase was used and the detector wavelength was set at 232 nm. Calibration solutions used in HPLC were ranging from 2 to 12 ?g/ml. An ANOVA test (P = 0.0226, F = 4.935) showed that the results obtained with the derivative UV spectrophotometric method were comparable to those obtained using reference methods.

Jain, P. S.; Jivani, H. N.; Khatal, R. N.; Surana, S. J.

2012-01-01

359

Quantitative Determination of Ciprofibrate in Tablets by Derivative UV Spectroscopy and RP-HPLC Method.  

PubMed

A derivative UV spectrophotometric and a reversed phase high-performance liquid chromatographic method for the determination of ciprofibrate in tablets was developed. The first-order derivative UV spectrophotometric method was found to be accurate with 100.57±0.97 recovery and precise with a coefficient of variation of 1.44. These results were compared to those obtained by reference methods, zero-order UV spectrophotometric method and a reversed-phase high-performance liquid chromatography method. A reversed-phase C(8) column with methanol:water (90:10, v/v, pH 3.7) mobile phase was used and the detector wavelength was set at 232 nm. Calibration solutions used in HPLC were ranging from 2 to 12 ?g/ml. An ANOVA test (P = 0.0226, F = 4.935) showed that the results obtained with the derivative UV spectrophotometric method were comparable to those obtained using reference methods. PMID:23326000

Jain, P S; Jivani, H N; Khatal, R N; Surana, S J

2012-03-01

360

Between-Method Variation in Human Chorionic Gonadotropin Test Results  

Microsoft Academic Search

Background: Results on sera and calibrators vary 1.4- to 2.3-fold among commercial human chorionic gonadotro- pin (hCG) assays. The relative contributions of calibra- tors, standards, hCG charge isoforms, and major struc- tural variants to this variation have not been quantified. Methods: Purified hCG was separated by isoelectric focusing into four fractions with pI ranges of 3- 4, 4 -5, 5-

Laurence A. Cole; Jaime M. Sutton; Trefor N. Higgins; George S. Cembrowski

361

Laboratory Evaluations of the Enterococcus qPCR Method for Recreational Water Quality Testing: Method Performance and Sources of Uncertainty in Quantitative Measurements  

EPA Science Inventory

The BEACH Act of 2000 directed the U.S. EPA to establish more expeditious methods for the detection of pathogen indicators in coastal waters, as well as new water quality criteria based on these methods. Progress has been made in developing a quantitative PCR (qPCR) method for en...

362

A comparative method based on ROC analysis for the quantitation of observer performance in scintigraphy.  

PubMed

A method is proposed for the evaluation of observer performance based on the concept of count density: it provides a description of the effects of different display or processing techniques that is easily graphed. A set of ROC curves is produced for use as a calibration for other ROC graphs. Each curve is obtained experimentally using the same series of images and varying only the count density. The effect of an image processing operation is evaluated by comparison with the calibration curves, and is expressed as the change in count density in unprocessed images that produces the same effect on an observer as the processing. The relative change in count density is defined as the gain of the processing operation. The method is used to quantitate the effects of three linear filters, and of their respective noise textures, on the detectability of spheres 3 cm in diameter immersed in a uniform background. The smoothing filters gave the largest gain (2.5) of the three. When stimulated image data were manipulated so that filtering changed the noise texture only, with spatial resolution and noise variance held constant, the smoothing filter provided a gain of about 0.25 for the targets considered; this corresponds to a loss of about 75% of the counts in an unprocessed image. PMID:7134266

Guignard, P A

1982-09-01

363

Prochlorococcus Ecotype Abundances in the North Atlantic Ocean As Revealed by an Improved Quantitative PCR Method  

PubMed Central

The cyanobacterium Prochlorococcus numerically dominates the photosynthetic community in the tropical and subtropical regions of the world's oceans. Six evolutionary lineages of Prochlorococcus have been described, and their distinctive physiologies and genomes indicate that these lineages are “ecotypes” and should have different oceanic distributions. Two methods recently developed to quantify these ecotypes in the field, probe hybridization and quantitative PCR (QPCR), have shown that this is indeed the case. To facilitate a global investigation of these ecotypes, we modified our QPCR protocol to significantly increase its speed, sensitivity, and accessibility and validated the method in the western and eastern North Atlantic Ocean. We showed that all six ecotypes had distinct distributions that varied with depth and location, and, with the exception of the deeper waters at the western North Atlantic site, the total Prochlorococcus counts determined by QPCR matched the total counts measured by flow cytometry. Clone library analyses of the deeper western North Atlantic waters revealed ecotypes that are not represented in the culture collections with which the QPCR primers were designed, explaining this discrepancy. Finally, similar patterns of relative ecotype abundance were obtained in QPCR and probe hybridization analyses of the same field samples, which could allow comparisons between studies.

Zinser, Erik R.; Coe, Allison; Johnson, Zackary I.; Martiny, Adam C.; Fuller, Nicholas J.; Scanlan, David J.; Chisholm, Sallie W.

2006-01-01

364

Quantitation of smooth muscle proliferation in cultured aorta. A color image analysis method for the Macintosh.  

PubMed

Color image analysis was used to assess proliferative changes in smooth muscle cells from cultured segments of rabbit aortas. Proliferating cells were labeled with bromodeoxyuridine (BrdU) and visualized by immunohistochemical staining of histologic sections. A Macintosh IIfx computer with a Data Translation digitizer board, Javelin color camera and a color-enhanced version of National Institutes of Health Image 1.31 image analysis software (ColorImage 1.31) was used to acquire red, green and blue (RGB)-filtered grayscale images from microscopic slides of control and treated aortas. The BrdU-labeled (brown) and nonlabeled, hematoxylin (blue)-stained nuclei were identified on the RGB gray-scale images using a thresholding technique and sampled for nuclear number and area. An increase in the number of BrdU-labeled nuclei in the region of experimental perturbation was demonstrated by this semiautomated method. Thus, this Macintosh-based color image analysis method proved to be effective in rapidly quantitating immunohistochemically defined smooth muscle proliferation in microscopic tissues. PMID:8318131

Kuyatt, B L; Reidy, C A; Hui, K Y; Jordan, W H

1993-04-01

365

Are extraction methods in quantitative assays of pharmacopoeia monographs exhaustive? A comparison with pressurized liquid extraction.  

PubMed

The extraction methods in selected monographs of the European and the Swiss Pharmacopoeia were compared to pressurized liquid extraction (PLE) with respect to the yield of constituents to be dosed in the quantitative assay for the respective herbal drugs. The study included five drugs, Belladonnae folium, Colae semen, Boldo folium, Tanaceti herba and Agni casti fructus. They were selected to cover different classes of compounds to be analyzed and different extraction methods to be used according to the monographs. Extraction protocols for PLE were optimized by varying the solvents and number of extraction cycles. In PLE, yields > 97 % of extractable analytes were typically achieved with two extraction cycles. For alkaloid-containing drugs, the addition of ammonia prior to extraction significantly increased the yield and reduced the number of extraction cycles required for exhaustive extraction. PLE was in all cases superior to the extraction protocol of the pharmacopoeia monographs (taken as 100 %), with differences ranging from 108 % in case of parthenolide in Tanaceti herba to 343 % in case of alkaloids in Boldo folium. PMID:16924586

Basalo, Carlos; Mohn, Tobias; Hamburger, Matthias

2006-08-21

366

Quantitative (1)H NMR method for hydrolytic kinetic investigation of salvianolic acid B.  

PubMed

This work presents an exploratory study for monitoring the hydrolytic process of salvianolic acid B (Sal B) in low oxygen condition using a simple quantitative (1)H NMR (Q-NMR) method. The quantity of the compounds was calculated by the relative ratio of the integral values of the target peak for each compound to the known amount of the internal standard trimethylsilyl propionic acid (TSP). Kinetic runs have been carried out on different initial concentrations of Sal B (5.00, 10.0, 20.0mg/mL) and temperatures of 70, 80, 90°C. The effect of these two factors during the transformation process of Sal B was investigated. The hydrolysis followed pseudo-first-order kinetics and the apparent degradation kinetic constant at 80°C decreased when concentration of Sal B increased. Under the given conditions, the rate constant of overall hydrolysis as a function of temperature obeyed the Arrhenius equation. Six degradation products were identified by NMR and mass spectrometric analysis. Four of these degradation products, i.e. danshensu (DSS), protocatechuic aldehyde (PRO), salvianolic acid D (Sal D) and lithospermic acid (LA) were further identified by comparing the retention times with standard compounds. The advantage of this Q-NMR method was that no reference compounds were required for calibration curves, the quantification could be directly realized on hydrolyzed samples. It was proved to be simple, convenient and accurate for hydrolytic kinetic study of Sal B. PMID:23867115

Pan, Jianyang; Gong, Xingchu; Qu, Haibin

2013-06-26

367

Comparison of methods for quantitative analysis of additives in low-density polyethylene using supercritical fluid and enhanced solvent extraction.  

PubMed

On-line supercritical fluid extraction-supercritical fluid chromatography (SFE-SFC) with cryogenic trapping was used to extract and separate five additives from a low-density polyethylene (LDPE) sample. A glass tube filled with glass wool afforded excellent collection efficiency for the extracted analytes. Additive spiked sand was employed to optimize the various parameters of the on-line SFE-SFC system. Calibration curves from the spiked sand studies for on-line SFE-SFC were obtained with good linearities for quantitation. Results obtained on additives in LDPE from on-line SFE-SFC were comparable to those from off-line SFE-HPLC and off-line enhanced solvent extraction (ESE)-HPLC for all additives except Irganox 1076. However, the precision obtained with on-line SFE-SFC was lower than that from off-line SFE-HPLC and off-line ESE-HPLC due to the small sample size employed in the on-line system. Considerable clean-up of the ESE extract was required prior to chromatographic analysis. On-line SFE-SFC minimized the sample handling and eliminated the use of organic solvent. Despite the lower than expected precision, the on-line SFE-SFC method for quantitation of polymer additives appears to be reliable and robust for application in routine quality control analysis. PMID:10551353

Zhou, L Y; Ashraf-Khorassani, M; Taylor, L T

1999-10-15

368

Emotional support and counselling for people with visual impairment: Quantitative findings from a mixed methods pilot study  

Microsoft Academic Search

Aims: This paper reports on mainly quantitative findings from a mixed methods evaluation of a new model of emotional support and counselling for people with moderate visual impairment. Method: The CORE Outcome Measure was completed with service users at baseline and post-intervention to assess the impact of the new service on psychological wellbeing and social functioning. Their perceived needs and

Wally Barr; Suzanne Hodge; Martina Leeven; Louise Bowen; Paul Knox

2012-01-01

369

Research and Evaluation in Education and Psychology: Integrating Diversity with Quantitative, Qualitative, and Mixed Methods. Second Edition  

ERIC Educational Resources Information Center

In this new edition, the author explains quantitative, qualitative, and mixed methods, and incorporates the viewpoints of various research paradigms (postpositivist, constructivist, transformative, and pragmatic) into descriptions of these methods. Special emphasis is provided for conducting research in culturally complex communities. Each chapter…

Mertens, Donna M.

2004-01-01

370

Research and Evaluation in Education and Psychology: Integrating Diversity with Quantitative, Qualitative, and Mixed Methods. Second Edition  

ERIC Educational Resources Information Center

|In this new edition, the author explains quantitative, qualitative, and mixed methods, and incorporates the viewpoints of various research paradigms (postpositivist, constructivist, transformative, and pragmatic) into descriptions of these methods. Special emphasis is provided for conducting research in culturally complex communities. Each…

Mertens, Donna M.

2004-01-01

371

Determination of Calcium in Cereal with Flame Atomic Absorption Spectroscopy: An Experiment for a Quantitative Methods of Analysis Course  

ERIC Educational Resources Information Center

|An experiment for determination of calcium in cereal using two-increment standard addition method in conjunction with flame atomic absorption spectroscopy (FAAS) is demonstrated. The experiment is intended to introduce students to the principles of atomic absorption spectroscopy giving them hands on experience using quantitative methods of…

Bazzi, Ali; Kreuz, Bette; Fischer, Jeffrey

2004-01-01

372

Monochloramine disinfection kinetics of Nitrosomonas europaea by propidium monoazide quantitative PCR and Live/Dead BacLight Methods  

EPA Science Inventory

Monochloramine disinfection kinetics were determined for the pure culture ammonia-oxidizing bacterium Nitrosomonas europaea (ATCC 19718) by two culture independent methods: (1) LIVE/DEAD® BacLight? (LD) and (2) propidium monoazide quantitative PCR (PMA-qPCR). Both methods were f...

373

D117 FULLPAT: A FULL-PATTERN QUANTITATIVE ANALYSIS PROGRAM AND METHOD FOR X-RAY POWDER DIFFRACTION  

Microsoft Academic Search

FULLPAT is a quantitative X-ray diffraction methodology that merges the advantages of existing full-pattern fitting methods with the traditional reference intensity ratio (RIR) method (1). FULLPAT can explicitly analyze all phases in a sample including partially ordered or amorphous phases such as clay minerals, polymers, or glasses. Use of an internal standard allows unconstrained analyses to be conducted by direct

Steve J. Chipera; David L. Bish

2003-01-01

374

A quantitative method to detect explosives and other selected semivolatiles in soil samples by Fourier transform infrared spectroscopy  

SciTech Connect

The current methods for hazardous waste site characterization are time consuming, cumbersome, and expensive. Typically, characterization requires a preliminary site assessment and subsequent sampling of potentially contaminated soils and waters. The samples are sent to laboratories for analysis using EPA-certified methods. It is often necessary to repeat the entire sampling-analysis cycle to characterize a site completely and accurately. For these reasons, new methods of site assessment and characterization are continually being researched. TWs paper describes a Fourier transform infrared (FTIR) spectroscopy method that rapidly screens soil samples from potentially hazardous waste sites. Analysis of a soil sample by FTIR takes approximately 10 minutes. The method has been developed to identify and quantify explosives in the field and is directly applicable to selected volatile organics, semivolatile organics, and pesticides. The soil samples are desorbed in a CDS 122 thermal desorption unit under vacuum into a variable pathlength, long-path cell heated to 180{degrees}C. The spectral data, 128 co-added scans at I cm{sup {minus}l} resolution, are collected and stored using a Nicolet 60SX FTIR spectrometer. Classical least squares (CLS) analysis has been used to obtain quantitative results.

Clapper-Gowdy, M.; Demirgian, J. (Argonne National Lab., IL (United States)); Lang, K.; Robaittaille, G. (Army Toxic and Hazardous Materials Agency, Aberdeen Proving Ground, MD (United States))

1992-01-01

375

A validated micellar electrokinetic chromatography method for the quantitation of dexamethasone, ondansetron and aprepitant, antiemetic drugs, in organogel.  

PubMed

A micellar electrokinetic chromatography (MEKC) method was developed for the determination of three anti-vomiting drugs (aprepitant, dexamethasone and ondansetron) in pharmaceutical formulations. The method was optimized using a central composite design (CCD). Four main factors (borate buffer concentration, pH, methanol content and sodium dodecyl sulfate concentration) were optimized in order to obtain best resolutions and peak efficiencies in a minimum runtime. The separation was performed in a fused-silica capillary. After optimization, the background electrolyte consisted of a borate buffer (62.5mM, pH 8.75) containing sodium dodecyl sulfate (77.5mM) and methanol (3.75%). Under these conditions, a complete separation of each antiemetic drug and its respective internal standards was achieved in 38min. The method was validated with trueness values from 94.9 to 107.2% and precision results (repeatability and intermediate precision) lower than 5.9%. MEKC-UV was the first method allowing the separation of aprepitant, dexamethasone and ondansetron and was suitable for the quantitation of these three antiemetic drugs in organogel formulations. The rapid sample preparation coupled with an automated separation technique make this method convenient for quality control of extemporaneous magistral ready-to-use formulation. PMID:23978340

Bourdon, Florence; Lecoeur, Marie; Duhaut, Marion; Odou, Pascal; Vaccher, Claude; Foulon, Catherine

2013-07-31

376

New method for the detection of micro-organisms in blood: application of quantitative interpretation model to aerobic blood cultures  

NASA Astrophysics Data System (ADS)

The physical and chemical changes occurring in blood that has been inoculated into a blood culture bottle can be used as means to detect the presence of microorganisms in blood cultures. These changes include primarily the conversion of oxy- to deoxyhemoglobin within the red blood cells (RBCs) and changes in the cell number densities. These changes in the physical and chemical properties of blood can be readily detected using spectrophometric methods thus enabling the continuous monitoring of blood culture vials to provide quantitative information on the growth behavior of the microorganisms present. This paper reports on the application of spectrophotometric information obtained from diffuse reflectance measurements of aerobic blood cultures to detect microbial growth and compares the results to those obtained using the standard blood culture system.

Huffman, Debra E.; Serebrennikova, Yulia M.; Smith, Jennifer M.; Leparc, German F.; García-Rubio, Luis H.

2009-05-01

377

Accurate and quantitative phase retrieval methods for a series of defocused images with application to in-line Gabor microscopy  

NASA Astrophysics Data System (ADS)

In 1948, Gabor proposed a lens-less in-line holographic microscope where the recorded hologram is a result of interference of both reference wave and the wave diffracted from the object. In this work, an analysis of the hologram formation and sampling issues are presented using the local-spatial frequency distribution at the camera plane. Techniques are presented that enable the reconstruction of the complex object wave at the camera plane from a series of defocused images. It is suggested to use the band-limited angular spectrum method for the back-propagation of the field components, so that an accurate and quantitative estimate of the object-wave at the object plane is obtained. The reconstruction procedure does not rely on the paraxial approximation and is therefore applicable to the case of high NA beams.

Falaggis, Konstantinos; Kozacki, Tomasz; Jozwik, Michal; Kujawinska, Malgorzata

2012-09-01

378

Detecting Method of Quantitative Colloidal Gold Test Strip Concentration Based on the DSP Image Processing  

Microsoft Academic Search

Immunogold labeling technique is mainly used on detecting of quantitative colloidal gold test strip concentration, through comparing with the color standard card to realize visual qualitative analysis, but the disadvantages are low measurement accuracy, high misjudgment rate, and it is difficult to achieve quantitative measurement. This paper adopts an embedded image processing system which based on the DSP. The image

Zheng Dezhi; Wu Zongling; Wang Shuai

2010-01-01

379

Effect of platform, reference material, and quantification model on enumeration of Enterococcus by quantitative PCR methods  

EPA Science Inventory

Quantitative polymerase chain reaction (qPCR) is increasingly being used for the quantitative detection of fecal indicator bacteria in beach water. QPCR allows for same-day health warnings, and its application is being considered as an optionn for recreational water quality testi...

380

Exploring the use of storytelling in quantitative research fields using a multiple case study method  

Microsoft Academic Search

The purpose of this study was to explore the emerging use of storytelling in quantitative research fields. The focus was not on examining storytelling in research, but rather how stories are used in various ways within the social context of quantitative research environments. In-depth interviews were conducted with seven professionals who had experience using storytelling in their work and my

Lori N. Hamlet Matthews

2008-01-01

381

Quantitative measurement of analyte gases in a microwave spectrometer using a dynamic sampling method  

Microsoft Academic Search

This article reports quantitative measurement of concentrations of water vapor (absorption line at 22.235 GHz) and ethylene oxide (absorption line at 23.123 GHz) in different gas mixtures by means of a microwave spectrometer. The problem of absorption line broadening and the gas memory problem inherent in the quantitative analysis of gases using microwave molecular rotational spectroscopy have been solved. The

Z. Zhu; I. P. Matthews; A. H. Samuel

1996-01-01

382

Initial Development and Validation of a Novel Extraction Method for Quantitative Mining of the Formalin-Fixed, Paraffin-Embedded Tissue Proteome for Biomarker Investigations  

PubMed Central

Annotated formalin-fixed, paraffin-embedded (FFPE) tissue archives constitute a valuable resource for retrospective biomarker discovery. However, proteomic exploration of archival tissue is impeded by extensive formalin-induced covalent cross-linking. Robust methodology enabling proteomic profiling of archival resources is urgently needed. Recent work is beginning to support the feasibility of biomarker discovery in archival tissues, but further developments in extraction methods which are compatible with quantitative approaches are urgently needed. We report a cost-effective extraction methodology permitting quantitative proteomic analyses of small amounts of FFPE tissue for biomarker investigation. This surfactant/heat-based approach results in effective and reproducible protein extraction in FFPE tissue blocks. In combination with a liquid chromatography?mass spectrometry-based label-free quantitative proteomics methodology, the protocol enables the robust representative and quantitative analyses of the archival proteome. Preliminary validation studies in renal cancer tissues have identified typically 250?300 proteins per 500 ng of tissue with 1D LC?MS/MS with comparable extraction in FFPE and fresh frozen tissue blocks and preservation of tumor/normal differential expression patterns (205 proteins, r = 0.682; p < 10?15). The initial methodology presented here provides a quantitative approach for assessing the potential suitability of the vast FFPE tissue archives as an alternate resource for biomarker discovery and will allow exploration of methods to increase depth of coverage and investigate the impact of preanalytical factors.

2010-01-01

383

Quantitative analysis of ecological effects for land use planning based on ecological footprint method: a case research in Nanyang City  

NASA Astrophysics Data System (ADS)

The research of coordinated development between land use and ecological building is a new problem with the development of country economy, whose intention is to improve economy development and protect eco-environment in order to realize regional sustainable development. Evaluating human effects on the ecosystem by a comprehensive, scientific and quantitative method is a critical issue in the process of general land use planning. At present, ecological footprint methodology, as an excellent educational tool applicable to global issues, is essential for quantifying humanity's consumption of natural capital, for overall assessments of human impact on earth as well as for general land use planning. However, quantitative studies on the development trends of ecological footprint (EF) time series and biological capacity (BC) time series in a given region are still rare. Taking Nanyang City as a case study, this paper presents two quantitative estimate indices over time scale called the change rate and scissors difference to quantitatively analyze the trends of EF and BC over the planning period in general land use planning form 1997-2004 and to evaluate the ecological effects of the land use general planning form 1997 to.2010. The results showed that: 1 In Nanyang city, trends of the per capita EF and BC were on the way round, and the ecological deficit enhanced from 1997 to 2010. 2 The difference between the two development trends of per capita EF and BC had been increasing rapidly and the conflict between the EF and BC was aggravated from 1997 to 2010. 3 The general land use planning (1997 - 2010) of Nanyang city had produced some positive effects on the local ecosystem, but the expected biological capacity in 2010 can hardly be realized following this trend. Therefore, this paper introduces a "trinity" land use model in the guidelines of environment- friendly land use pattern and based on the actual situation of Nanyang city, with the systemic synthesis of land utilization of the cities, the village and the suburb as a principal part and the land development reorganization and the ecological environment construction as the key point.

Zhang, Jing; Liu, Yaolin; Chen, Xinming

2008-10-01

384

Studies on the UV spectrum of poly(?-glutamic acid) based on development of a simple quantitative method.  

PubMed

A simple and valid ultraviolet (UV) spectrophotometric method for the determination of poly(?-glutamic acid) is developed. The method is based on the UV absorption spectrum of ?-PGA in aqueous solution, which exhibits a maximum absorption wavelength at 216 nm. The results obtained were comparable to those obtained with the reported high-performance liquid chromatography (HPLC) method according to ICH guidelines. Under the proposed procedure, the calibration graph is linear over the range of 20-200 ?g/ml with regression correlation coefficient of 0.9997. Precision (%R.S.D.<1.50) and recovery (%R.>99.29%) are good. The limit of detection (LOD) and limit of quantitation (LOQ) are 0.39 and 1.19 ?g/ml, respectively. These results agree well with those of HPLC method. Its spectrum properties studies showed that the spectrum of ?-PGA remarkably changed with an increase in temperature due to ?-PGA was digested into glutamate monomer. In spite of this, the determining procedure could carried out in a wide temperature range (25-50°C). In addition, the method is not influenced by the molecular weight, but the measurement system need to control in pH 3.0-10.0 and ionic strength not more than 0.5M. The proposed method is applied successfully for high-throughput quantification of poly(?-glutamic acid) in biological samples. The advantages of the UV method are simplicity of operation, rapidity, sensitive, low-cost and high-throughput. PMID:22521620

Zeng, Wei; Chen, Guiguang; Zhang, Yunkai; Wu, Kongyang; Liang, Zhiqun

2012-04-12

385

Spectral simulation methods for enhancing qualitative and quantitative analyses based on infrared spectroscopy and quantitative calibration methods for passive infrared remote sensing of volatile organic compounds  

NASA Astrophysics Data System (ADS)

Infrared spectroscopy (IR) has over the years found a myriad of applications including passive environmental remote sensing of toxic pollutants and the development of a blood glucose sensor. In this dissertation, capabilities of both these applications are further enhanced with data analysis strategies employing digital signal processing and novel simulation approaches. Both quantitative and qualitative determinations of volatile organic compounds are investigated in the passive IR remote sensing research described in this dissertation. In the quantitative work, partial least-squares (PLS) regression analysis is used to generate multivariate calibration models for passive Fourier transform IR remote sensing measurements of open-air generated vapors of ethanol in the presence methanol as an interfering species. A step-wise co-addition scheme coupled with a digital filtering approach is used to attenuate the effects of variation in optical path length or plume width. For the qualitative study, an IR imaging line scanner is used to acquire remote sensing data in both spatial and spectral domains. This technology is capable of not only identifying but also specifying the location of the sample under investigation. Successful implementation of this methodology is hampered by the huge costs incurred to conduct these experiments and the impracticality of acquiring large amounts of representative training data. To address this problem, a novel simulation approach is developed that generates training data based on synthetic analyte-active and measured analyte-inactive data. Subsequently, automated pattern classifiers are generated using piecewise linear discriminant analysis to predict the presence of the analyte signature in measured imaging data acquired in remote sensing applications. Near infrared glucose determinations based on the region of 5000--4000 cm-1 is the focus of the research in the latter part of this dissertation. A six-component aqueous matrix of glucose in the presence of five other interferent species, all spanning physiological levels, is analyzed quantitatively. Multivariate PLS regression analysis in conjunction with samples designated into a calibration set is used to formulate models for predicting glucose concentrations. Variations in the instrumental response caused by drift and environmental factors are observed to degrade the performance of these models. As a remedy, a model updating approach based on spectral simulation is developed that is highly successful in eliminating the adverse effects of non-chemical variations.

Sulub, Yusuf Ismail

386

Analysis of Perfluorinated Chemicals in Sludge: Method Development and Initial Results  

EPA Science Inventory

A fast, rigorous method was developed to maximize the extraction efficacy for ten perfluorocarboxylic acids and perfluorooctanesulfonate from wastewater-treatment sludge and to quantitate using liquid chromatography, tandem-mass spectrometry (LC/MS/MS). First, organic solvents w...

387

Trajectory planning method for reduced patient risk in image-guided neurosurgery: concept and preliminary results  

NASA Astrophysics Data System (ADS)

We present a new preoperative planning method to quantify and help reduce the risk associated with needle and tool insertion trajectories in image-guided keyhole neurosurgery. The goal is to quantify the risk of a proposed straight trajectory, and/or to find the trajectory with the lowest risk to nearby brain structures based on pre-operative CT/MRI images. The method automatically computes the risk associated with a given trajectory, or finds the trajectory with the lowest risk to nearby brain structures based on preoperative image segmentation and on a risk volume map. The surgeon can revise the suggested trajectory, add a new one using interactive 3D visualization, and obtain a quantitative risk measure. The trajectory risk is evaluated based on the tool placement uncertainty, on the proximity of critical brain structures, and on a predefined table of quantitative geometric risk measures. Our preliminary results on a clinical dataset with eight targets show a significant reduction in trajectory risk and a shortening of the preoperative planning time as compared to the conventional method.

Shamir, Reuben R.; Joskowicz, Leo; Antiga, Luca; Foroni, Roberto I.; Shoshan, Yigal

2010-03-01

388

Quantitative Analysis in the General Chemistry Laboratory: Training Students to Analyze Individual Results in the Context of Collective Data  

ERIC Educational Resources Information Center

|Titration experiments are ideal for generating large data sets for use in quantitative-analysis activities that are meaningful and transparent to general chemistry students. We report the successful implementation of a sophisticated quantitative exercise in which the students identify a series of unknown acids by determining their molar masses…

Ling, Chris D.; Bridgeman, Adam J.

2011-01-01

389

Quantitative evaluation of an automatic segmentation method for 3D reconstruction of intervertebral scoliotic disks from MR images  

PubMed Central

Background For some scoliotic patients the spinal instrumentation is inevitable. Among these patients, those with stiff curvature will need thoracoscopic disk resection. The removal of the intervertebral disk with only thoracoscopic images is a tedious and challenging task for the surgeon. With computer aided surgery and 3D visualisation of the interverterbral disk during surgery, surgeons will have access to additional information such as the remaining disk tissue or the distance of surgical tools from critical anatomical structures like the aorta or spinal canal. We hypothesized that automatically extracting 3D information of the intervertebral disk from MR images would aid the surgeons to evaluate the remaining disk and would add a security factor to the patient during thoracoscopic disk resection. Methods This paper presents a quantitative evaluation of an automatic segmentation method for 3D reconstruction of intervertebral scoliotic disks from MR images. The automatic segmentation method is based on the watershed technique and morphological operators. The 3D Dice Similarity Coefficient (DSC) is the main statistical metric used to validate the automatically detected preoperative disk volumes. The automatic detections of intervertebral disks of real clinical MR images are compared to manual segmentation done by clinicians. Results Results show that depending on the type of MR acquisition sequence, the 3D DSC can be as high as 0.79 (±0.04). These 3D results are also supported by a 2D quantitative evaluation as well as by robustness and variability evaluations. The mean discrepancy (in 2D) between the manual and automatic segmentations for regions around the spinal canal is of 1.8 (±0.8) mm. The robustness study shows that among the five factors evaluated, only the type of MRI acquisition sequence can affect the segmentation results. Finally, the variability of the automatic segmentation method is lower than the variability associated with manual segmentation performed by different physicians. Conclusions This comprehensive evaluation of the automatic segmentation and 3D reconstruction of intervertebral disks shows that the proposed technique used with specific MRI acquisition protocol can detect intervertebral disk of scoliotic patient. The newly developed technique is promising for clinical context and can eventually help surgeons during thoracoscopic intervertebral disk resection.

2012-01-01

390

Quantitative assessment of MS plaques and brain atrophy in multiple sclerosis using semiautomatic segmentation method  

NASA Astrophysics Data System (ADS)

Quantitative magnetic resonance (MR) imaging of the brain is useful in multiple sclerosis (MS) in order to obtain reliable indices of disease progression. The goal of this project was to estimate the total volume of gliotic and non gliotic plaques in chronic progressive multiple sclerosis with the help of a semiautomatic segmentation method developed at the Ragnar Granit Institute. Youth developed program running on a PC based computer provides de displays of the segmented data, in addition to the volumetric analyses. The volumetric accuracy of the program was demonstrated by segmenting MR images of fluid filed syringes. An anatomical atlas is to be incorporated in the segmentation system to estimate the distribution of MS plaques in various neural pathways of the brain. A total package including MS plaque volume estimation, estimation of brain atrophy and ventricular enlargement, distribution of MS plaques in different neural segments of the brain has ben planned for the near future. Our study confirmed that total lesion volumes in chronic MS disease show a poor correlation to EDSS scores but show a positive correlation to neuropsychological scores. Therefore accurate total volume measurements of MS plaques using the developed semiautomatic segmentation technique helped us to evaluate the degree of neuropsychological impairment.

Heinonen, Tomi; Dastidar, Prasun; Ryymin, Pertti; Lahtinen, Antti; Eskola, Hannu; Malmivuo, Jaakko

1997-05-01

391

Cervical laminoplasty (Hattori's method). Procedure and follow-up results.  

PubMed

Posterior decompression plus posterior reconstruction (laminoplasty) is a useful surgical method for treatment of cervical compressive myelopathy. There are many laminoplasty procedures. This paper describes the Z-shaped laminoplasty developed by Hattori in 1971, and presents a clinical follow-up of the authors' experience with 130 patients. The procedure involves grinding the laminae down with an air drill and making a Z-shaped cut into the thinned laminae without excising the laminae. This technique enlarges the spinal canal. The purpose of this technique is to decompress the spinal cord and at the same time maintain clinical stability. Postoperative results were satisfactory without any major complication. Follow-up study was conducted in 78 cases with a minimal follow-up period of more than 2 years. Satisfactory clinical results were maintained for long periods postoperatively, and the enlargement of the spinal canal was well maintained as demonstrated on follow up X-ray study. PMID:3144758

Kawai, S; Sunago, K; Doi, K; Saika, M; Taguchi, T

1988-11-01

392

Binary neutron-star mergers with Whisky and SACRA: First quantitative comparison of results from independent general-relativistic hydrodynamics codes  

SciTech Connect

We present the first quantitative comparison of two independent general-relativistic hydrodynamics codes, the whisky code and the sacra code. We compare the output of simulations starting from the same initial data and carried out with the configuration (numerical methods, grid setup, resolution, gauges) which for each code has been found to give consistent and sufficiently accurate results, in particular, in terms of cleanness of gravitational waveforms. We focus on the quantities that should be conserved during the evolution (rest mass, total mass energy, and total angular momentum) and on the gravitational-wave amplitude and frequency. We find that the results produced by the two codes agree at a reasonable level, with variations in the different quantities but always at better than about 10%.

Baiotti, Luca [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, 606-8502 (Japan); Institute of Laser Engineering, Osaka University, Suita, 565-0871 (Japan); Shibata, Masaru [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, 606-8502 (Japan); Yamamoto, Tetsuro [Yugen Club, Toyama, Shinjuku, Tokyo, 162-0052 (Japan)

2010-09-15

393

Combinative method using HPLC fingerprint and quantitative analyses for quality consistency evaluation of an herbal medicinal preparation produced by different manufacturers.  

PubMed

A combinative method using HPLC-DAD fingerprint and quantitative analysis was developed and validated for manufacturer-to-manufacturer quality consistency evaluation of Yiqing preparations. For fingerprint analysis, 22 peaks were selected as the characteristic peaks to evaluate the similarities of different samples collected from different manufacturers. The similarities of 12 Yiqing samples were beyond 0.90, indicating that samples from different manufacturers were, to some extent, consistent. Additionally, simultaneous quantification of nine markers including berberine, aloe-emodin, rhein, emodin, chrysophanol, baicalin, baicalein, wogonoside, and wogonin in Yiqing was performed to interpret the quality consistency. The results from the quantitative data showed that the contents of these nine marker compounds were quite consistent for batches produced within one manufacturer and significantly different from manufacturer-to-manufacturer. This study demonstrated that a combination of the chromatographic fingerprint and quantitative analysis offers an efficient way to quality consistency evaluation of herbal preparation. PMID:20138726

Li, Yan; Wu, Tao; Zhu, Jinghui; Wan, Lili; Yu, Qi; Li, Xingxia; Cheng, Zhihong; Guo, Cheng

2010-01-20

394

Quantitative evaluation of automatic methods for lesions detection in breast ultrasound images  

NASA Astrophysics Data System (ADS)

Ultrasound (US) is a useful diagnostic tool to distinguish benign from malignant breast masses, providing more detailed evaluation in dense breasts. Due to the subjectivity in the images interpretation, computer-aid diagnosis (CAD) schemes have been developed, increasing the mammography analysis process to include ultrasound images as complementary exams. As one of most important task in the evaluation of this kind of images is the mass detection and its contours interpretation, automated segmentation techniques have been investigated in order to determine a quite suitable procedure to perform such an analysis. Thus, the main goal in this work is investigating the effect of some processing techniques used to provide information on the determination of suspicious breast lesions as well as their accurate boundaries in ultrasound images. In tests, 80 phantom and 50 clinical ultrasound images were preprocessed, and 5 segmentation techniques were tested. By using quantitative evaluation metrics the results were compared to a reference image delineated by an experienced radiologist. A self-organizing map artificial neural network has provided the most relevant results, demonstrating high accuracy and low error rate in the lesions representation, corresponding hence to the segmentation process for US images in our CAD scheme under tests.

Marcomini, Karem D.; Schiabel, Homero; Carneiro, Antonio Adilton O.

2013-02-01

395

Quantitative ultrasound method to detect and monitor laser-induced cavitation bubbles.  

PubMed

An ultrasound technique to measure the spatial and temporal behavior of the laser-induced cavitation bubble is introduced. The cavitation bubbles were formed in water and in gels using a nanosecond pulsed Nd:YAG laser operating at 532 nm. A focused, single-element, 25-MHz ultrasound transducer was employed both to detect the acoustic emission generated by plasma expansion and to acoustically probe the bubble at different stages of its evolution. The arrival time of the passive acoustic emission was used to estimate the location of the cavitation bubble's origin and the time of flight of the ultrasound pulse-echo signal was used to define its spatial extent. The results of ultrasound estimations of the bubble size were compared and found to be in agreement with both the direct optical measurements of the stationary bubble and the theoretical estimates of bubble dynamics derived from the well-known Rayleigh model of a cavity collapse. The results of this study indicate that the proposed quantitative ultrasound technique, capable of detecting and accurately measuring laser-induced cavitation bubbles in water and in a tissue-like medium, could be used in various biomedical and clinical applications. PMID:18601556

Karpiouk, Andrei B; Aglyamov, Salavat R; Bourgeois, Frederic; Ben-Yakar, Adela; Emelianov, Stanislav Y

396

Detection of Upper Airway Obstruction With Spirometry Results and the Flow-Volume Loop: A Comparison of Quantitative and Visual Inspection Criteria  

Microsoft Academic Search

BACKGROUND: There are important gaps in our understanding of the epidemiology and diagnosis of upper-airway obstruction. METHODS: We examined the diagnostic value of several criteria for pre- dicting upper-airway obstruction, and we measured the frequency of detecting upper-airway obstruc- tion via quantitative and visual assessment of flow-volume loops. We studied 4 quantitative and 3 visual criteria for their ability to

Ravindra Gudavalli; Kevin McCarthy; Xiaobo Liu; James K Stoller

2009-01-01

397

Movement Correction Method for Human Brain PET Images: Application to Quantitative Analysis of Dynamic [18F]-FDDNP Scans  

PubMed Central

Head movement during a PET scan (especially, dynamic scan) can affect both the qualitative and quantitative aspects of an image, making it difficult to accurately interpret the results. The primary objective of this study was to develop a retrospective image-based movement correction (MC) method and evaluate its implementation on dynamic [18F]-FDDNP PET images of cognitively intact controls and patients with Alzheimer’s disease (AD). Methods Dynamic [18F]-FDDNP PET images, used for in vivo imaging of beta-amyloid plaques and neurofibrillary tangles, were obtained from 12 AD and 9 age-matched controls. For each study, a transmission scan was first acquired for attenuation correction. An accurate retrospective MC method that corrected for transmission-emission misalignment as well as emission-emission misalignment was applied to all studies. No restriction was assumed for zero movement between the transmission scan and first emission scan. Logan analysis with cerebellum as the reference region was used to estimate various regional distribution volume ratio (DVR) values in the brain before and after MC. Discriminant analysis was used to build a predictive model for group membership, using data with and without MC. Results MC improved the image quality and quantitative values in [18F]-FDDNP PET images. In this subject population, medial temporal (MTL) did not show a significant difference between controls and AD before MC. However, after MC, significant differences in DVR values were seen in frontal, parietal, posterior cingulate (PCG), MTL, lateral temporal (LTL), and global between the two groups (P < 0.05). In controls and AD, the variability of regional DVR values (as measured by the coefficient of variation) decreased on average by >18% after MC. Mean DVR separation between controls and ADs was higher in frontal, MTL, LTL and global after MC. Group classification by discriminant analysis based on [18F]-FDDNP DVR values was markedly improved after MC. Conclusion The streamlined and easy to use MC method presented in this work significantly improves the image quality and the measured tracer kinetics of [18F]-FDDNP PET images. The proposed MC method has the potential to be applied to PET studies on patients having other disorders (e.g., Down syndrome and Parkinson’s disease) and to brain PET scans with other molecular imaging probes.

Wardak, Mirwais; Wong, Koon-Pong; Shao, Weber; Dahlbom, Magnus; Kepe, Vladimir; Satyamurthy, Nagichettiar; Small, Gary W.; Barrio, Jorge R.; Huang, Sung-Cheng

2010-01-01

398

Validation of a quantitative NMR method for suspected counterfeit products exemplified on determination of benzethonium chloride in grapefruit seed extracts  

Microsoft Academic Search

A 1H-nuclear magnetic resonance (NMR) spectroscopy method for quantitative determination of benzethonium chloride (BTC) as a constituent of grapefruit seed extract was developed. The method was validated, assessing its specificity, linearity, range, and precision, as well as accuracy, limit of quantification and robustness. The method includes quantification using an internal reference standard, 1,3,5-trimethoxybenzene, and regarded as simple, rapid, and easy

Somer Bekiroglu; Olle Myrberg; Kristina Östman; Marianne Ek; Torbjörn Arvidsson; Torgny Rundlöf; Birgit Hakkarainen

2008-01-01

399

Application of the 5?-Nuclease PCR Assay in Evaluation and Development of Methods for Quantitative Detection of Campylobacter jejuni  

PubMed Central

Campylobacter jejuni is recognized as a leading human food-borne pathogen. Traditional diagnostic testing for C. jejuni is not reliable due to special growth requirements and the possibility that this bacterium can enter a viable but nonculturable state. Nucleic acid-based tests have emerged as a useful alternative to traditional enrichment testing. In this article, we present a 5?-nuclease PCR assay for quantitative detection of C. jejuni and describe its evaluation. A probe including positions 381121 to 381206 of the published C. jejuni strain NCTC 11168 genome sequence was identified. When this probe was applied, the assay was positive for all of the isolates of C. jejuni tested (32 isolates, including the type strain) and negative for all other Campylobacter spp. (11 species tested) and several other bacteria (41 species tested). The total assay could be completed in 3 h with a detection limit of approximately 1 CFU. Quantification was linear over at least 6 log units. Quantitative detection methods are important for both research purposes and further development of C. jejuni detection methods. In this study, we used the assay to investigate to what extent the PCR signals generated by heat-killed bacteria interfere with the detection of viable C. jejuni after exposure at elevated temperatures for up to 5 days. An approach to the reduction of the PCR signal generated by dead bacteria was also investigated by employing externally added DNases to selectively inactivate free DNA and exposed DNA in heat-killed bacteria. The results indicated relatively good discrimination between exposed DNA from dead C. jejuni and protected DNA in living bacteria.

Nogva, Hege Karin; Bergh, Anette; Holck, Askild; Rudi, Knut

2000-01-01

400

Preliminary Results from a Mercury Dry Deposition Measurement Methods Intercomparison  

NASA Astrophysics Data System (ADS)

Over the past fifteen years, a number of intensive field campaigns and measurement networks have provided valuable information on the estimated rates of mercury wet deposition to sensitive ecosystems throughout the world. In contrast, the ability to place bounds on the rates of mercury dry deposition has been hampered by the relative lack of direct measurements of this process. Recently, a number of researchers have performed measurements of mercury dry deposition using a variety of direct and indirect measurement techniques. While these studies have provided important information regarding the potential rates of mercury dry deposition to natural surfaces, little is known about the comparability of the results utilizing these different measurement approaches. During the month of August 2008, a mercury dry deposition measurement methods comparison was conducted in Ann Arbor, Michigan over a nine-day period. Seven research groups participated in the study, with the following measurement approaches: water, cation exchange membrane, chemically treated filter and turf surrogate surfaces; and several micrometeorological modeling methods. Continuous monitoring was conducted for ambient meteorological conditions and elemental, oxidized and particulate mercury concentrations. Preliminary results suggest that study-average mercury dry deposition estimates ranged from 0.17 to 0.59 ng/m2/hour for the group of pure-water surrogate surfaces, the cation exchange membrane and a micrometeorological flux gradient approach. The turf surrogate surface, BrCl spiked-water surface and a gold-coated quartz fiber filter surface resulted in significantly higher mercury dry deposition estimates, with the latter two approaches having been designed to measure total mercury dry deposition. Given that the turf surrogate surface and the cation exchange membrane samplers were designed for long-term deployment (up to one week), these methods were deployed for an additional series of four one-week periods. The turf surrogate surface again resulted in a significantly greater estimate of mercury dry deposition (1.59 ng/m2/hour) than that obtained using the cation exchange membrane (0.19 ng/m2/hour). When the turf surrogate surface estimate was adjusted for total surface area, as opposed to its footprint area, the deposition estimate (0.17 ng/m2/hour) was more consistent with that obtained from the cation exchange membrane.

Marsik, F. J.; Brooks, S.; Gustin, M. S.; Holsen, T.; Landis, M.; Prestbo, E. M.; Poissant, L.

2009-12-01

401

The AutoQual ultrasound elastography method for quantitative assessment of lateral strain in post-rupture Achilles tendons.  

PubMed

This paper presents the AutoQual elastography method: a novel algorithm that improves the quality of 2D displacement field calculation from ultrasound radio frequency (RF) sequences of acutely ruptured Achilles tendons to determine image-lateral strain fields and has potential use for ligaments and muscles. This method uses 2D bicubic spline interpolation of the RF signal, Quality Determined Search, Automatic Search Range and Adaptive Block Size components as a novel combination that is designed to improve continuity and decrease displacement field noise, especially in areas of low signal strength. We present a simple experiment for quantitatively comparing the AutoQual method to a multiscale (MS) elastography method from ultrasound RF sequences of a 5% agar phantom for rigid body motion and known lateral strain loads with speeds up to 5mm/s. We finally present examples of four in vivo Achilles tendons in various damage states and with manual or artificially controlled passive flexion of the foot. Results show that the AutoQual method offers a substantial improvement on the MS method, achieving similar performance for rigid body tracking at all speeds, a lower normalized square error at all strains induced and a more continuous strain field at higher compression rates. AutoQual also showed a greater average normalized cross correlation for image blocks in the area of interest, a lower standard deviation of the strain field and a visually more acceptable point tracking for in vivo examples. This work demonstrates lateral ultrasound elastography which is robust to the complex passive motion of the Achilles and to various imaging artifacts associated with imaging tendon rupture. This method potentially has a wide clinical application for assessing in vivo strains in and hence mechanical function of any near skin surface tissues that are longitudinally loaded. PMID:24001929

Brown, Phillip G; Alsousou, Joseph; Cooper, Ashley; Thompson, Mark S; Noble, J Alison

2013-08-20

402

Quantitative Comparison of Spot Detection Methods in Live-Cell Fluorescence Microscopy Imaging  

Microsoft Academic Search

In live-cell fluorescence microscopy imaging, quantitative analysis of biological image data generally involves the detection of many subresolution objects, appearing as diffraction-limited spots. Due to acquisition limitations, the signal-to-noise ratio (SNR) can be ex- tremely low, making automated spot detection a very challenging task. In this paper, we quantitatively evaluate the performance of the most frequently used supervised and unsupervised

Ihor Smal; Marco Loog; Wiro J. Niessen; Erik H. W. Meijering

2009-01-01

403

Development of a Laser Nephelometric Method for the Quantitation of Human Glycohemoglobins  

Microsoft Academic Search

A nephelometric procedure for quantitative measurement of glycohemoglobin (Hb A1) was developed, evaluated, and compared with the semi-quantitative mini-column chromatographic procedure. Hb A1 was purified from human red cell hemolystate by Bio-Rex 70 ion-exchange liquid chromatography and was used for standards and immunization. The antisera raised in rabbits showed high cross-reactivities with normal human hemoglobin (Hb A). The latter was

Peter P. Chou; Julius Kerkay; Manjula K. Gupta

1981-01-01

404

Qualitative and Quantitative Method Comparison in Animal-Assisted Therapy Research  

Microsoft Academic Search

While there have been many presentations and anecdotal evidence in support of AAT, quantitative empirically validated studies are very limited. Without quantitative empirical studies to support the effectiveness of AAT, it remains an unproven complement to traditional physical and psychotherapeutic practices (Kruger & Serpell,2010). The value and importance of non-empirical literature on AAT,including therapists’ observations, various author’s personal experiences, and

Laura Denenholz

2011-01-01

405

Partial least-squares methods for spectral analyses. 1. Relation to other quantitative calibration methods and the extraction of qualitative information  

Microsoft Academic Search

Partial least-squares (PLS) methods for spectral analyses are related to other multivariate calibration methods such as classical least-squares (CLS), inverse least-squares (ILS), and principal component regression (PCR) methods which have been used often in quantitative spectral analyses. The PLS method which analyzes one chemical component at a time is presented, and the basis of each step in the algorithm is

David M. Haaland; Edward V. Thomas

1988-01-01

406

Effect of test method on pop plot results  

NASA Astrophysics Data System (ADS)

CTH hydrocode simulations performed for this study demonstrate that test method can affect shock reactivity measurements as displayed on the POP plot. For run distances greater than about 7 mm and pressures lower than 50 kbar, the run distances produced with the use of a flyer plate were shorter than those produced by a plane wave lens system. In contrast, the run distances were similar for pressures above 50 kbar. The plane wave lens system simulated was based on a 4' PWL used at the Army Research Laboratory and a combination of buffer plates. The sample explosive was taken to be Composition C4. Other simulations showed that measuring an average velocity of the buffer plate outside the center of the buffer plate will result in lower input pressures being calculated from the Rankine-Hugoniot jump conditions than those that would be calculated if the corresponding peak initial velocity at the buffer plate center was used.

Sutherland, Gerrit

2012-03-01

407

Interferometric SAR phase difference calibration: Methods and results  

SciTech Connect

This paper addresses the steps necessary to determine and maintain the phase calibration of a two-channel interferometric synthetic aperture radar (IFSAR). The method, setup, and accuracy of four different calibration techniques are compared. The most novel technique involves pointing the interferometric baseline at nadir and imaging a lake surface. The other techniques include measuring various flat surfaces in traditional side-looking IFSAR maps, in-flight closed-loop calibration path measurements, and static laboratory measurements. Initial results indicate that, using combinations of these measurements, it is possible to maintain the interferometric phase calibration of Sandia National Laboratories` K{sub U} Band IFSAR to better than 3 degrees. The time variability of various parts of the calibration and requirements for recalibration are also discussed.

Bickel, D.L.; Hensley, W.H.

1993-12-31

408

Quantitative computed tomography for the prediction of pulmonary function after lung cancer surgery: a simple method using simulation software  

Microsoft Academic Search

Objective: The prediction of pulmonary functional reserve is mandatory in therapeutic decision-making for patients with resectable lung cancer, especially those with underlying lung disease. Volumetric analysis in combination with densitometric analysis of the affected lung lobe or segment with quantitative computed tomography (CT) helps to identify residual pulmonary function, although the utility of this modality needs investigation. Methods: The subjects

Kazuhiro Ueda; Toshiki Tanaka; Tao-Sheng Li; Nobuyuki Tanaka; Kimikazu Hamano

2009-01-01

409

Chromatography–tandem mass spectrometry method for the simultaneous quantitation of metoprolol succinate and simvastatin in human plasma  

Microsoft Academic Search

The liquid chromatographic–tandem mass spectrometry method was developed for the accurate quantitation of metoprolol succinate (MET) and simvastatin (SIM) in human plasma which were obtained from the pharmacokinetic (PK) study. The sample purification and pre-concentration was performed by protein precipitation technique using propranolol hydrochloride as working internal standard (WIS). The chromatographic separation was achieved using an isocratic mobile phase consisting

P. Senthamil Selvan; T. K. Pal

2009-01-01

410

Direct Determination of Sodium Fluoride and Sodium Monofluorophosphate in Toothpaste by Quantitative 19F-NMR: A Green Analytical Method  

Microsoft Academic Search

Sodium fluoride and sodium monofluorophosphate are often used as fluoridizers in oral care products to prevent dental caries. By quantitative F-NMR, their contents in toothpaste were simultaneously determined. This is a simple, fast, interference-free, and green analytical method for the determination of sodium fluoride and sodium monofluorophosphate in toothpaste.

Dongli Deng; Pengchi Deng; Xiaoyan Wang; Xiandeng Hou

2009-01-01

411

Method A: Enterococci in Water by TaqMan (Trade Name) Quantitative Polymerase Chain Reaction (qPCR) Assay.  

National Technical Information Service (NTIS)

Method A describes a quantitative polymerase chain reaction (qPCR) procedure for the detection of DNA from enterococci bacteria in ambient water matrices based on the amplification and detection of a specific region of the large subunit ribosomal RNA gene...

2010-01-01

412

DEVELOPMENT OF A RAPID, QUANTITATIVE METHOD FOR THE DETECTION OF INFECTIVE COXSACKIE AND ECHO VIRUSES IN DRINKING WATER  

EPA Science Inventory

The objectives of this research are to improve on the current analytical methods for quantitative detection of infective coxsackie and echo viruses in drinking water. The specific objectives of this research are to: (1) Improve the sensitivity and specificity of IMS-PCR for in...

413

A convenience UPLC\\/PDA method for the quantitative analysis of panaxfuraynes A and B from Panax ginseng  

Microsoft Academic Search

Panaxfurayne A and B, biologically novel tetrahydrofuranic polyacetylene glycosides, were founded from roots of Panax ginseng C. A. Meyer (Araliaceae). To study the contents of panaxfurynes A and B, a quantitative analysis method was developed using ultra performance liquid chromatography (UPLC) coupled with photo diode array detector. The dried (65°C, 72h) and powdered sample (5g) was extracted with ethanol (15%,

Sang Myung Lee; Hyang Burm Lee; Cheal Gyu Lee

2010-01-01

414

Structure?Specific, Quantitative Methods for Analysis of Sphingolipids by Liquid Chromatography–Tandem Mass Spectrometry: “Inside?Out” Sphingolipidomics  

Microsoft Academic Search

Due to the large number of highly bioactive subspecies, elucidation of the roles of sphingolipids in cell structure, signaling, and function is beginning to require that one perform structure?specific and quantitative (i.e., “sphingolipidomic”) analysis of all individual subspecies, or at least of those are relevant to the biologic system of interest. As part of the LIPID MAPS Consortium, methods have

M. Cameron Sullards; Jeremy C. Allegood; Samuel Kelly; Elaine Wang; Christopher A. Haynes; Hyejung Park; Yanfeng Chen; Alfred H. Merrill

2007-01-01

415

A Bayesian method for calculating real-time quantitative PCR calibration curves using absolute plasmid DNA standards  

Microsoft Academic Search

BACKGROUND: In real-time quantitative PCR studies using absolute plasmid DNA standards, a calibration curve is developed to estimate an unknown DNA concentration. However, potential differences in the amplification performance of plasmid DNA compared to genomic DNA standards are often ignored in calibration calculations and in some cases impossible to characterize. A flexible statistical method that can account for uncertainty between

Mano Sivaganesan; Shawn Seifring; Manju Varma; Richard A. Haugland; Orin C. Shanks

2008-01-01

416

Quantitative Methods for Long-Range Environmental Forecasting: Long-Range European Projections. Volume I. Summary Volume.  

National Technical Information Service (NTIS)

The overall purpose of this Interim Technical Report is to provide a basis for the improvement of long-range environmental forecasting through the use of quantitative methods. This voulme provides a summary of the technical work that is presented in the s...

G. R. Franco H. M. Weil A. Greenberg L. German D. Hartwick

1974-01-01

417

Quantitative Methods for Long-Range Environmental Forecasting: Long-Range European Projections. Volume III. Research Guide.  

National Technical Information Service (NTIS)

The overall purpose of this Interim Technical Report is to provide the basis for the improvement of long-range environmental forecasting through the use of quantitative methods. This volume provides a step by step procedure that analysts can use to genera...

G. R. Franco M. R. Leavitt

1974-01-01

418

Teaching Integrative Physiology Using the Quantitative Circulatory Physiology Model and Case Discussion Method: Evaluation of the Learning Experience  

ERIC Educational Resources Information Center

|One of the problems that we have found when teaching human physiology in a Spanish medical school is that the degree of understanding by the students of the integration between organs and systems is rather poor. We attempted to remedy this problem by using a case discussion method together with the Quantitative Circulatory Physiology (QCP)…

Rodriguez-Barbero, A.; Lopez-Novoa, J. M.

2008-01-01

419

"What about People Our Age?" Applying Qualitative and Quantitative Methods to Uncover How Political Ads Alienate College Students  

ERIC Educational Resources Information Center

|This study uses a sequential transformative mixed methods research design to explain how political advertising fails to engage college students. Qualitative focus groups examined how college students interpret the value of political advertising to them, and a quantitative manifest content analysis concerning ad framing of more than 100 ads from…

Parmelee, John H.; Perkins, Stephynie C.; Sayre, Judith J.

2007-01-01

420