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At least 469 records · Page 26Linked to original sources

PubMed2002

Participatory ergonomics: determining injury control "buy-in" of US Army cadre.

Overuse injuries account for the majority of lost duty time profiles for soldiers attending Advanced Individual Training (AIT) to become a Combat Medic at Ft. Sam Houston (63% for men and 74% for women). An intervention program was initiated with two AIT Battalions (BN) in an effort to reduce overuse injuries. The purpose of this paper is to describe methods of tracking the participation of supervisors during the intervention program. Methods used to monitor participation included recording the number of coordinating meetings, keeping minutes of advisory committee meetings, and conducting perception surveys. Over an 18-month period, the number of coordinating meetings decreased. Surveys identified the opinions, values, and self-identified roles of supervisors (drill sergeants and cadre) in regard to injury prevention with their assigned student-soldiers before and after an intervention program. At the initiation of the injury control program, 103 individuals completed a 27 question, anonymous survey to assist planners with developing a strategy that would encourage participation of cadre and drill sergeants in preventing injuries. One year later, 191 individuals from the same battalion completed the same survey. Results revealed a slight, statistically insignificant, decrease in supervisors' perception of the presence of overuse injuries in their BN (31.4% vs. 27.4%, p>0.05), and the level of acceptable injuries moved from the 16-30% range to the 1-10% range (chi2=4.65, p<0.05). Post-intervention, more supervisors believed their physical training programs could impact overuse injuries (pre 20.4% vs. post 31.6%, Chi2=6.7, p<0.01). The results reveal several methods to track the involvement of participants, to develop intervention strategies, and to monitor cultural shifts necessary to the injury control process.

Ergonomics↗

PubMedDate not supplied

Advances in analytical techniques for neutron capture therapy: thin layer chromatography matrix and track etch thin layer chromatography methods for boron-10 analysis.

A new track etch autoradiographic technique for quantitating boron-10 containing compounds used for neutron capture therapy is described. Instead of applying solutions of Cs2B12H11SH and its oxidation products directly to solid-state nuclear track detectors, diethylaminoethyl cellulose thin layer chromatography (TLC) plates are utilized as sample matrices. The plates are juxtaposed with Lexan polycarbonate detectors and irradiated in a beam of thermal neutrons. The detectors are then chemically etched, and the resultant tracks counted with an optoelectronic image analyzer. Sensitivity to boron-10 in solution reaches the 1 pg/microliter level, or 1 ppb. In heparinized blood samples, 100 pg boron-10/microliter are detected. This TLC matrix method has the advantage that sample plates can be reanalyzed under different reactor conditions to optimize detector response to the boron-10 carrier material. Track etch/TLC allows quantitation of the purity of boron neutron capture therapy compounds by utilizing the above method with TLC plates developed in solvent systems that resolve Cs2B12H11SH and its oxidative analogs. Detectors irradiated in juxtaposition to the thin layer chromatograms are chemically etched, and the tracks are counted in the sample lane from the origin of the plate to the solvent front. A graphic depiction of the number of tracks per field yields a quantitative analysis of compound purity.

Boron↗

PubMedDate not supplied

The disparity change score: a new methodology to examine health disparities in New Mexico.

OBJECTIVES: One overarching goal of Healthy People 2010 is to eliminate health disparities. Reducing disparities improves the overall health status of a population but is a lengthy process. The disparity change score (DCS) is a method for tracking health disparities over time. METHODS: Rates, rate ratios, and DCSs were calculated to track disparities during two time periods by sex, race/ethnicity, education, and income for key health indicators. Time periods were 10 years apart for all death indicators; length between time periods varied for other indicators depending on data collection systems. RESULTS: Sex-, race/ethnicity-, education-, and income-based disparities and disparity changes for New Mexico were identified. In general, males, American Indians, and those with the lowest income and education experienced the greatest health disparities. Five disparities that are worsening were identified for targeted interventions, mainly for males (firearm-related death and suicide) and American Indians (diabetes death and influenza/pneumonia death), but also for white non-Hispanics (drug-related death). CONCLUSIONS: Examining disparities at one point in time discounts disparity change over time. The DCS can help identify large disparities that are worsening and toward which resources for targeted interventions can be redirected. New Mexico should consider interventions for the five key disparities identified in this study.

Ethnicity↗

PubMed2001

A fast calibration method for 3-D tracking of ultrasound images using a spatial localizer.

We have developed a fast calibration method for computing the position and orientation of 2-D ultrasound (US) images in 3-D space where a position sensor is mounted on the US probe. This calibration is required in the fields of 3-D ultrasound and registration of ultrasound with other imaging modalities. Most of the existing calibration methods require a complex and tedious experimental procedure. Our method is simple and it is based on a custom-built phantom. Thirty N-fiducials (markers in the shape of the letter "N") embedded in the phantom provide the basis for our calibration procedure. We calibrated a 3.5-MHz sector phased-array probe with a magnetic position sensor, and we studied the accuracy and precision of our method. A typical calibration procedure requires approximately 2 min. We conclude that we can achieve accurate and precise calibration using a single US image, provided that a large number (approximately ten) of N-fiducials are captured within the US image, enabling a representative sampling of the imaging plane.

Calibration↗

PubMed2003

Recommendations for microbial source tracking: lessons from a methods comparison study.

The methods comparison study described in accompanying manuscripts demonstrated the potential value of microbial source tracking (MST) techniques, but also identified a need for method refinement. This paper provides three classes of recommendations to improve MST technology: optimization, development and evaluation. Optimization recommendations focus on library-dependent methods and include improved selection of restriction enzymes or antibiotics, better definition of appropriate library size, selection of target species and choice of statistical pattern-matching algorithms. Methods development recommendations focus on identifying new genomic targets and quantification procedures for library-independent methods. Longer-term methods development recommendations include integration of microarrays and other direct pathogen detection technology with MST. Studies defining host specificity and population dynamics should aid selection of target species during methods development. Evaluation recommendations include enhancements that should be incorporated into future methods comparison studies, along with studies to assess the value of MST results for risk characterization.

Animals↗

PubMed2003

A descriptive analysis of hypertension and affiliated therapies in a military retiree population (ages 40-85 years) at Camp Lejeune, North Carolina.

Because current methods of tracking hypertension are time-consuming and expensive, the prevalence of hypertension in retired military populations is often unknown. Tracking military retiree hypertension is important because it can help to conserve scarce resources and save lives by preventing strokes and other diseases. Intended as a case study, an alternative method of tracking hypertension using pharmacy records and ambulatory data system records to confirm diagnosis of hypertension was used to determine the prevalence of hypertension in a retired military population (ages 40-85 years). The results indicated that matching pharmacy data with ICD9 401 diagnosis data and medical records is a more efficient method of tracking hypertension.

Aged↗

PubMed1996

MRI of myocardial function: motion tracking techniques.

Methods for the noninvasive measurement of three-dimensional myocardial motion with MRI have recently been developed using presaturation tagging and velocity-encoded phase maps. The quality of clinical cardiac MRI studies has also recently improved with the advent of breath-hold scanning. The combination of breath-hold imaging with tagging and velocity-encoding sequences has made the measurement of myocardial wall motion in patients a simple and reproducible exam. These methods make it possible to quantify the severity and extent of regional heart wall motion abnormalities both at rest and during stress. This article reviews the MRI techniques developed for these applications.

Fourier Analysis↗

PubMed2004

Multiscale vessel tracking.

A method is presented that uses a vectorial multiscale feature image for wave front propagation between two or more user defined points to retrieve the central axis of tubular objects in digital images. Its implicit scale selection mechanism makes the method more robust to overlap and to the presence of adjacent structures than conventional techniques that propagate a wave front over a scalar image representing the maximum of a range of filters. The method is shown to retain its potential to cope with severe stenoses or imaging artifacts and objects with varying widths in simulated and actual two-dimensional angiographic images.

Algorithms↗

PubMed2006

A method for quantitative cell tracking using SPECT for the evaluation of myocardial stem cell therapy.

PURPOSE: A promising SPECT-based method for evaluating stem cells therapy uses (111)In-labelled cells, transfected with a reporter gene. Cells are first transplanted to the infarct, and subsequently interrogated for transgenic expression using a systemic injection of an (131)I-labelled reporter probe. The method is impeded by the physical effects of scatter, (131)I/(111)In cross-talk, and attenuation. We hypothesize that correcting for physical effects improves detection of transgenic expression in transplanted cells when (111)In localization is available. METHODS: Canine bone marrow mesenchymal cells (BMMCs), radiolabelled and transfected, were injected into infarcted myocardium. Next, a reporter probe was injected systemically, and 22 SPECT scans were acquired over 20 h. Finally, (99m)Tc-sestamibi was injected and imaged. The animal was killed, the heart sectioned, and counted for (131)I and (111)In in a well-counter ('gold standard'). Canine SPECTs were reconstructed in two ways: with corrections for physical effects and without corrections. The first (111)In reconstruction and the (99m)Tc reconstruction were used to define volumes-of-interest over the transplanted BMMC (VBMMC) and normal myocardium (VNM), respectively. RESULTS: (131)I reconstructions without corrections for physical effects had negligible differential uptake. With corrections, VBMMC was consistently higher than VNM, demonstrating transgene expression. (131)I had the following VBMMC:VNM activity ratio: without correction for physical effects=0.869; with corrections=1.23; and well-counter=1.21. VNM showed the following (131)I:(111)In activity ratio: without corrections=3.07; with corrections=1.38; and well-counter=1.58. CONCLUSIONS: In dual-isotope SPECT, corrections for physical effects were required to detect transgene expression in cells transplanted into an infarction when localization information was available.

Animals↗

PubMed2005

Use of superparamagnetic microbeads in tracking subretinal injections.

PURPOSE: The purpose of these studies was to develop a method to track intraocular injections. METHODS: Retinal pigment epithelial (RPE) cells, purified from adult mouse eyes, were incubated with superparamagnetic microbeads (Dynabeads, 4.5 microm) coated with bovine serum albumin to verify that they could phagocytose the microbeads. For in vivo tracking studies, mice were anesthetized and a small incision was made at the pars plana and 2 mul of microbeads (around 10(5) microbeads) or RPE that had taken up the microbeads were injected into the subretinal space (SRS). Mice were sacrificed at various times after injection. The eyes were enucleated, fixed in formalin, and embedded in paraffin. Sections were stained with H&E, visualized by light microscopy. Some eyes were digested with collagenase and inflammatory cells determined by flow cytometry. RESULTS: Cultured adult RPE phagocytosed the magnetic microbeads. One day after injection into the SRS, a retinal detachment was observed at the injection point and free microbeads were easily detected at this site. One week later, the host RPE cells had phagocytized the microbeads and the retina had reattached. No inflammatory response was detected in the eyes that were injected with microbeads in the SRS at any time examined. Histology showed normal morphology of all retinal layers around the injection site. The microbeads remained in situ throughout the study. CONCLUSIONS: Protein coated magnetic microbeads are non-inflammatory after injection into the SRS. Host RPE cells phagocytized the microbeads and the retina maintained a healthy morphology after reattachment. This technique proved not only to be a good training tool to determine the precise location of injection, but also provided a noninflammatory method for long term marking of delivery into the SRS. However, the microbeads can not be used as a tracer of injected RPE because the microbeads were readily transferred to the endogenous RPE.

Animals↗

PubMed2003

Fast tracking of cardiac motion using 3D-HARP.

MR tagging is considered as a valuable technique to evaluate regional myocardial function quantitatively and noninvasively, however the cumbersome and time-consuming post-processing procedures for cardiac motion tracking still hinder its application to routine clinical examination. We present a fast and semiautomatic method for tracking 3D cardiac motion from short-axis (SA) and long-axis (LA) tagged MRI images. The technique, called 3D-HARP (HARmonic Phase), is based on the HARP method and extends this method to track 3D motion. A material mesh model is built to represent a collection of material points inside the left ventricle (LV) wall. The phase time-invariance property of material points is used to track the mesh points. For a series of 9 timeframe MRI images, the total time required for initializing settings, building the mesh, and tracking 3D cardiac motion is approximately 10 minutes. Further analysis of Langrangian strain and twist angle demonstrates that during systole, the lateral LV wall shows a greater strain values than the septum and the SA slices from the base to the apex show a gradual change in twist pattern.

Algorithms↗

PubMed1988

Computerized tracking for newborn screening and follow-up: a review.

In the third decade of newborn screening for phenylketonuria (PKU) and other disorders computers are being used increasingly for both the laboratory and the follow-up aspects of screening programs. In 1984 slightly less than 40% of the state programs had automated follow-up. Lack of funding is probably the major inhibitor of more widespread use of computers in tracking newborns through the newborn screening process. It is suggested that federal funds be made available to ensure wider distribution of currently used tracking systems and development of methods for tracking newborns from birth through follow-up.

Follow-Up Studies↗

PubMed2006

Ensuring accountability: the contribution of the cohort review method to tuberculosis control in New York City.

SETTING: In 1993, the New York City (NYC) Bureau of Tuberculosis Control developed the cohort review process as a quality assurance method to track and improve patient outcomes. METHODS: The Bureau Director reviews every tuberculosis (TB) case quarterly in a multi-disciplinary staff meeting. In 2004 we also began collecting details on issues identified at cohort review to quantify how this process directly impacts TB control efforts. RESULTS: From 1992 to 2004, NYC TB cases decreased by 72.7% and treatment success rates significantly increased by 26.7%. Implementing the cohort review was key to improving case management, thus leading to these results. For the 1039 patients in 2004, 596 issues were identified among 424 patients; 55.0% were incorrect, unclear or unknown patient information, 13.8% were treatment issues, 12.4% were case management issues and 10.6% were incomplete contact investigations. Most (76.5%) issues were addressed within 30 days of the cohort reviews. CONCLUSION: A systematic review of every TB case improves the quality of patient information, enhances patient treatment and ensures accountability at all levels of the TB control program.

Case Management↗

PubMed2004

Use of the noninvasive GlucoWatch Biographer during exercise of varying intensity.

The GlucoWatch Biographer (Cygnus, Inc., Redwood City, CA), a novel, noninvasive method for tracking glucose, makes frequent, automatic glucose measurements. Therefore, it potentially can provide a convenient method of tracking glycemia, particularly with exercise as an added variable in diabetes management. The purpose of the investigation was (1) to measure the effectiveness of this device, and (2) to determine the validity of its readings, during rest and exercise both indoors and outdoors. Four subjects with type 1 diabetes and five controls without diabetes participated in rest, mild [40% of heart rate reserve (HRR) for 45 min], moderate (60% of HRR for 30 min), and heavy exercise (80% of HRR for 15 min) both indoors and outdoors. Subjects monitored blood glucose levels (forearm alternate site testing), and readings were taken by the GlucoWatch during and following testing conditions. Significantly more GlucoWatch readings were obtained during rest (55.6% outdoors, 66.7% indoors) than during moderate (11.1%) or heavy (0%; P < 0.01) exercise. A similar number was obtained during mild outdoor exercise (46.6%), but not indoors (29.2%). Sweating rates corresponded to a reduced effectiveness during indoor exercise only (P < 0.01), where sweating was heavier despite higher outdoor temperatures. A weak association between GlucoWatch and matched glucometer readings (r = 0.81; P < 0.01) was found. The effectiveness of the GlucoWatch Biographer during any moderate to heavy exercise was extremely poor, as was the validity of its readings compared with forearm alternate site testing. Thus, anyone wishing to engage in daily exercise would be best advised to abstain from wearing the GlucoWatch except during rest or mild exercise.

Adult↗

PubMed1997

Leg cycling tracking by dynamic vision.

This study describes a method of tracking of human body limbs from a monocular sequence of perspective images. These objects and the associated articulations must be modelled. The principle of the method is based on the interpretation of image features as the three-dimensional perspective projections points of the object model and an iterative process method to compute the model position in accordance with the analysed image. This attitude is filtered (Kalman filter) to predict the model position relative to the next image of the sequence. The image features are extracted locally according to the computed prediction. Tracking experiments, illustrated in this study by a leg cycling sequence, have been conducted to demonstrate the viability of the approach.

Bicycling↗

PubMedDate not supplied

Diffusion tensor fiber tracking of human brain connectivity: aquisition methods, reliability analysis and biological results.

We present a description, biological results and a reliability analysis for the method of diffusion tensor tracking (DTT) of white matter fiber pathways. In DTT, diffusion-tensor MRI (DT-MRI) data are collected and processed to visualize the line trajectories of fiber bundles within white matter (WM) pathways of living humans. A detailed description of the data acquisition is given. Technical aspects and experimental results are illustrated for the geniculo-calcarine tract with broad projections to visual cortex, occipital and parietal U-fibers, and the temporo-calcarine ventral pathway. To better understand sources of error and to optimize the method, accuracy and precision were analyzed by computer simulations. In the simulations, noisy DT-MRI data were computed that would be obtained for a WM pathway having a helical trajectory passing through gray matter. The error vector between the real and ideal track was computed, and random errors accumulated with the square root of track length consistent with a random-walk process. Random error was most dependent on signal-to-noise ratio, followed by number of averages, pathway anisotropy and voxel size, in decreasing order. Systematic error only occurred for a few conditions, and was most dependent on the stepping algorithm, anisotropy of the surrounding tissue, and non-equal voxel dimensions. Both random and systematic errors were typically below the voxel dimension. Other effects such as track rebound and track recovery also depended on experimental conditions. The methods, biological results and error analysis herein may improve the understanding and optimization of DTT for use in various applications in neuroscience and medicine.

Adult↗

PubMed2003

Fluorescence polarization: a novel indicator of cardiomyocyte contraction.

The changes measured in intracellular fluorescein fluorescence polarization (IFFP) are used as a new tool for tracing cytoplasmic effects during contractile cycles of cardiac myocytes (1-2-day-old rat hearts), in addition to the established Ca(2+) monitoring and/or videometric methods of tracking cell-shortening. This novel method was found to be non-intrusive to the contraction cycles. The decay of the transient IFFP signal (from 0.220+/-0.01 to 0.170+/-0.013) seems to be closely related to the extended phase of contractile activation. This fact was further supported when Ca(2+) exchanger inhibitor was introduced and significantly decreased (90%) the rate of beats of contraction and IFFP, but not the Ca(2+) beat rate changes. This result suggests that the IFFP indicator is probably associated with the physiological activation, rather than with Ca(2+) alterations. The IFFP measure monitors the average of effective changes in the micro-viscosity of the cytoplasm protein matrix, associated with cellular activation.

Animals↗

PubMed2005

Data acceptance for automated leukocyte tracking through segmentation of spatiotemporal images.

A crucial task in inflammation research and inflammatory drug validation is leukocyte velocity data collection from microscopic video imagery. Since manual methods are bias-prone and extremely time consuming, automated tracking methods are required to compute cell velocities. However, an automated tracking method is of little practical use unless it is accompanied by a mechanism to validate the tracker output. In this paper, we propose a validation technique that accepts or rejects the output of automated tracking methods. The proposed method first generates a spatiotemporal image from the cell locations given by a tracking method; then, it segments the spatiotemporal image to detect the presence or absence of a leukocyte. For segmenting the spatiotemporal images, we employ an edge-direction sensitive nonlinear filter followed by an active contour based technique. The proposed nonlinear filter, the maximum absolute average directional derivative (MAADD), first computes the magnitude of the mean directional derivative over an oriented line segment and then chooses the maximum of all such values within a range of orientations of the line segment. The proposed active contour segmentation is obtained via growing contours controlled by a two-dimensional force field, which is constructed by imposing a Dirichlet boundary condition on the gradient vector flow (GVF) field equations. The performance of the proposed validation method is reported here for the outputs of three different tracking techniques: the method was successful in 97% of the trials using manual tracking, in 94% using correlation tracking and in 93% using active contour tracking.

Algorithms↗