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At least 1,693 records · Page 94Linked to original sources

PubMed2004

Intensity-modulated radiation therapy for oropharyngeal carcinoma: impact of tumor volume.

PURPOSE: To assess the therapeutic outcomes in oropharyngeal cancer patients treated with intensity-modulated radiotherapy (IMRT) and analyze the impact of primary gross tumor volume (GTV) and nodal GTV (nGTV) on survival and locoregional control rates. METHODS AND MATERIALS: Between February 1997 and September 2001, 74 patients with squamous cell carcinoma of the oropharynx were treated with IMRT. Thirty-one patients received definitive IMRT; 17 also received platinum-based chemotherapy. Forty-three patients received combined surgery and postoperative IMRT. The median follow-up for all patients was 33 months (range, 9-60 months). Fifty-two patients (70.3%) had Stage IV disease, 17 patients (23%) had Stage III, 3 patients (4.1%) had Stage II, and 2 patients (2.7%) had Stage I tumors. The mean prescription dose was 70 and 66 Gy, respectively, for the definitive and postoperative cohorts. The daily fraction dose was either 1.9 or 2 Gy, five times weekly. The GTV and/or nGTV were determined and derived using the Computational Environment for Radiotherapy Research, a free software package developed at Washington University. The mean GTV was 30.5 +/- 22.3 cm(3), and the mean nGTV was 23.2 +/- 20.6 cm(3). RESULTS: Ten locoregional failures were observed. Six patients died of disease and three died of concurrent disease. Distant metastasis developed in 6 patients. The 4-year estimate of overall survival was 87%, and the 4-year estimate of disease-free survival was 81% (66% in the definitive vs. 92% in the postoperative RT group). The 4-year estimate of locoregional control was 87% (78% in the definitive vs. 95% in the postoperative RT group); the 4-year estimate of distant metastasis-free survival was 90% (84% in the definitive vs. 94% in the postoperative group). Multivariate analysis showed that GTV and nGTV were independent risk factors determining locoregional control and disease-free survival for definitive oropharyngeal IMRT patients. The worst late toxicities documented were as follows: 32 patients with Grade 1 and 9 with Grade 2 xerostomia; 2 with Grade 1 and 1 with Grade 2 skin toxicity; 3 with Grade 1 late mucositis; and 3 with Grade 1 trismus. Seventeen patients required gastrostomy tube placement. CONCLUSION: IMRT is an effective treatment modality for locally advanced oropharyngeal carcinoma. The GTV and nGTV are the most important factors predictive of therapeutic outcome.

Adult↗

PubMed2006

Analysis of skin movement with respect to flexional bone motion using MR images of a hand.

This study describes the methodology for analyzing skin movement with respect to the predefined flexional motion of the hand. The 3D in vivo geometric data were acquired through magnetic resonance (MR) scanning of multiple hands in various postures. Custom software was developed to segment MR images and to generate polygonal isosurfaces. A new bone coordinate system (BCS) was defined to describe the skin movement measured with the skin-surface markers. The BCS was defined by the surface registration technique, which could minimize the distance among the 3D polygonal surfaces of different postures. MR images of six subjects in the 3 postures were captured with skin-surface markers for the experiment. Skin movement on the second metacarpal bone, which was fixed during the flexional motion, ranged from 1.169 to 10.885 mm. While the distance of the skin movement varied from one subject to another, a common skin movement direction was observed among the six subjects. For the repeatability evaluation of the proposed method, the MR images of the same subject were independently processed 10 times by a trained operator. The standard deviation of the skin movement on the second metacarpal of the index finger with respect to the predefined flexional motion ranged from 0.45 to 0.74 mm.

Bone and Bones↗

PubMed2005

Solid waste generation from oil and gas industries in United Arab Emirates.

Solid wastes generated from oil and gas industrial activities are very diverse in their characteristics, large in their amounts and many of which are hazardous in nature. Thus, quantifying and characterizing the generated amounts in association with their types, classes, sources, industrial activities, and their chemical and biological characteristics is an obvious mandate when evaluating the possible management practices. This paper discusses the types, amounts, generation units, and the factors related to solid waste generation from a major oil and gas field in the United Arab Emirates (Asab Field). The generated amounts are calculated based on a 1-year data collection survey and using a database software specially developed and customized for the current study. The average annual amount of total solid waste generated in the studied field is estimated at 4061 t. Such amount is found equivalent to 650 kg/capita, 0.37 kg/barrel oil, and 1.6 kg/m3 of extracted gas. The average annual amount of hazardous solid waste is estimated at 55 t and most of which (73%) is found to be generated from gas extraction-related activities. The majority of other industrial non-hazardous solid waste is generated from oil production-related activities (41%), The present analysis does also provide the estimated generation amounts per waste type and class, amounts of combustible, recyclable, and compostable wastes, and the amounts dumped in uncontrolled way as well as disposed into special hazardous landfill facilities. The results should help the decision makers in evaluating the best alternatives available to manage the solid wastes generated from the oil and gas industries.

Conservation of Natural Resources↗

PubMedDate not supplied

Redesigning courses for the World Wide Web.

The use of computer-based instructional technologies has become almost ubiquitous in education, including health professions education. In addition, clinical practice requires the use of digital information, networking, and continued learning. Faculty, students, and clinicians must be prepared to use computer-based technologies and telecommunications. Many faculty members in the health professions need assistance with the transfer of traditional (campus-based) courses or course material to the World Wide Web. This article presents the instructional design and pedagogical aspects of redesigning a traditional campus-based course for the World Wide Web. Specific steps and a template are identified. The development of a virtual community of learners is also discussed as a critical element of on-line teaching and learning.

Computer-Assisted Instruction↗

PubMed2006

SuperState: a computer program for the control of operant behavioral experimentation.

Operant behavioral researches require precise control of experimental devices for delivering stimuli and monitoring behavioral responses. The author developed a software solution named SuperState for controlling hardware devices and running reinforcement schedules. The Microsoft Windows compatible software was written by use of an object-oriented programming language Borland Delphi 5.0, which has simplified the programming of the application. SuperState is a stand-alone easy-to-use green software, without the need for the experimenter to master any scripting languages. It features: (1) control of multiple operant cages running independent reinforcement schedules; (2) enough cage devices (16 digital inputs and 16 digital outputs for each cage) suitable for the need of most operant behavioral equipments; (3) control of most standard ISA-type digital interface cards including Med-Associates Super-port cards and a PCI-type card AC6412, and highly expandable to support other PCI-type interface cards; (4) high-resolution device control (1ms); (5) a built-in real-time cumulative recorder; (6) extensive data analyzing including event recorder, cumulative recorder, block analyzing; the summarized results can be transferred easily to Microsoft Excel spreadsheets through the Clipboard.

Animals↗

PubMed2004

Assessment of tremor: a new computerised tool for clinical practice.

The quantitative assessment of tremor represents the main difficulty in clinical evaluation. We developed a software package - T-Lab - for the biomechanical analysis of hyperkinetic movement disorders. This software can receive and elaborate data from an electronic device interfaced with a personal computer. The aim of our study was to verify the validity of the PC-aided method proposed in the routine assessment of tremor. We did this by a correlation (regression) analysis between the scores obtained by Webster's Amplitude Clinical Scale and the amplitude data by T-Lab and between EMG data and frequency measures of T-Lab. Forty-seven patients presenting with upper limb tremor were enrolled. Four series of data were obtained: two series for frequency and two for amplitude. A significant correlation between all sets of data compared was found. T-Lab represents a valid, objective and useful device of quantifying tremors in clinical practice.

Adolescent↗

PubMed2006

Comparison of the shaping ability of RaCe and FlexMaster rotary nickel-titanium systems in simulated canals.

The aim of this study was to compare the shaping ability of RaCe and FlexMaster rotary nickel-titanium instruments in simulated canals. A total of 80 canals with four different shapes were prepared with either RaCe or FlexMaster instruments. Pre- and postoperative images of each canal were recorded and combined using image analysis software. The development of canal aberrations and transportation was assessed. There was a significant difference (p < 0.001) between the systems for time of preparation to apical size 30, .06 taper; FlexMaster instruments took on average 1.86 min and RaCe 1.66 min. One RaCe and two FlexMaster instruments fractured. No zips, elbows, or danger zones were created. One perforation and eight outer widenings were created using FlexMaster instruments; RaCe instruments created two outer widenings. No differences were found between the instruments for direction of transportation. RaCe and FlexMaster nickel-titanium instruments prepared canals rapidly with few aberrations.

Dental Alloys↗

PubMed2004

A multicommuted flow system for the determination of dextrose in parenteral and hemodialysis concentrate solutions.

A new method is presented for the automation of the determination of dextrose in parenteral and hemodialysis solutions. The method is based on multicommutation flow analysis (MCFA) and exploits enzymatic reactions providing a colored derivative that is detected spectrophotometrically (Trinder's method). The reagent, comprising glucose oxidase, peroxidase, 4-hydroxybenzoate and a buffer was obtained from a commercial kit for the determination of glycemia. The flow system used three 3-way solenoid valves operating under computer control. The necessary software was developed for the purpose and compiled in QuickBASIC 4.0 The influence of some operating variables (segment size, number of segments and reactor length) was studied. Calibration curves in the range 0-1g/L presented a slight curvature and were fitted with a second-degree polynomial (h=-0.0632C(2)+0.6039C+0.166, r(2)=0.9973, h being the peak-height (absorbance) and C the concentration in g/L). The method was validated by analyzing artificial samples presenting accurately known concentrations of dextrose, and comparing the results with the known value and with value obtained by polarimetry. Recoveries were in the range 96.6-100.2%, and the difference with the polarimetric analysis was in the range 0.1-3.3%. Precision (R.S.D.,%) was better than 2.4%. Sampling frequency of the system was 90 samples/h, with a reagent consumption of 0.14 mL per sample.

Algorithms↗

PubMedDate not supplied

Right ventricular pressure-volume loops using simultaneous radionuclide angiography with a multiwire gamma camera and right heart catheterization.

BACKGROUND: The purpose of this study was to generate right ventricular (RV) pressure-volume loops (PVLs) from time-activity curves obtained by first-pass radionuclide angiography (RNA) and RV pressures obtained by right heart catheterization. METHODS AND RESULTS: Short-lived tantalum 178 was used to obtain first-pass RNA at baseline (n = 31), after nitroglycerin (n = 5), or after the conclusion of cardiac catheterization (n = 13). From the radionuclide-derived RV ejection fraction and thermodilution stroke volume, the RV end-diastolic volume and end-systolic volume were measured. Special proprietary software was developed and used to integrate the pressure and the RNA data. The mean heart rate was 80 +/- 17 beats/min; RV ejection fraction, 39% +/- 12%; RV end-diastolic volume, 217 +/- 79 mL; RV end-systolic volume, 142 +/- 74 mL; and RV end-diastolic pressure, 10 +/- 7 mm Hg. The RV PVLs were of high quality and reproducible. CONCLUSIONS: This study provides proof of concept of the feasibility of generating RV PVL; the short half-life (10 minutes) and low energy (59 keV) of Ta-178 allow the generation of multiple loops at low radiation exposure. Such studies could be performed at the bedside and provide a wealth of information that may have clinical and research merits.

Blood Pressure↗

PubMed2004

Effects of rotation on measurement of lower limb alignment for knee osteotomy.

The purposes of this study were to clarify the effects of rotation on two-dimensional measurement of lower limb alignment for knee osteotomy using a three-dimensional method and to determine whether this 3-D simulation method could help with planning of knee osteotomy. We developed computer software to calculate femorotibial angle (FTA) and hip-knee-ankle angle (HKA) and simulate knee osteotomy from a CT-based 3-D bone model of the lower limb. Lower limb rotation on anteroposterior long-standing radiographs was measured by superimposing the 3-D bone models. Changes in alignment with limb rotation were calculated using the software. FTA after virtual closed-wedged osteotomy was measured for a hypothetical case of a rotation error of the osteotomy plane in reattaching the proximal cutting surface to the distal cutting surface. For 31 varus knees in 20 patients with medial compartment arthritis, the mean rotation angle, relative to the epicondylar axis, with variable limb position was 7.4 +/- 3.9 degrees of internal rotation (mean +/- SD), ranging from 8 degrees of external rotation to 14 degrees of internal rotation; the mean changes in FTA and HKA were 3.5 +/- 2.2 degrees (range, 0.4-8.6) and 1.6 +/- 1.3 degrees (range, 0.2-4.9), respectively. The FTA "flexion angle" (lateral view alignment from neutral AP) and the absolute HKA "flexion angle" correlated with the change in FTA and HKA with limb rotation, respectively (FTA, R = 0.999; HKA, R = 0.993). The mean change in FTA after virtual closed-wedged osteotomy was 3.2 degrees for internal and external 10 degrees rotation errors in reattaching the osteotomy plane. Rotation may affect measurement of lower limb alignment for knee osteotomy, and 3-D methods are preferable for surgical planning.

Adult↗

PubMed2005

Modeling plant morphogenesis.

Applications of computational techniques to developmental plant biology include the processing of experimental data and the construction of simulation models. Substantial progress has been made in these areas over the past few years. Complex image-processing techniques are used to integrate sequences of two-dimensional images into three-dimensional descriptions of development over time and to extract useful quantitative traits. Large amounts of data are integrated into empirical models of developing plant organs and entire plants. Mechanistic models link molecular-level phenomena with the resulting phenotypes. Several models shed light on the possible properties of active auxin transport and its role in plant morphogenesis.

Computer Simulation↗

PubMedDate not supplied

Assessing visual attention in young children and adolescents with severe mental retardation utilizing conditional-discrimination tasks and multiple testing procedures.

To effectively reduce overselective attention, a fine-grained analysis of the control exhibited by compound training cues is first needed. Computer software was developed in this study to administer two different stimulus control-testing procedures to assess how three young children of normal development and three adolescents with severe mental retardation attended to stimulus compounds when conditional-discrimination tasks were provided. One test assessed stimulus control by determining response accuracy for each component of the S+ compounds. The other testing procedure measured the response topographies of the compound stimuli using a touch screen attached to a computer monitor screen. After pretraining each stimulus component, all three children attended simultaneously to two elements in a conditional-discrimination task with few errors occurring. The adolescents with mental retardation eventually attended to both elements simultaneously but required more pretraining and exposure to the conditional-discrimination tasks before simultaneous attention occurred. Since the adolescents with severe mental retardation learned to simultaneously attend to multiple cues in the conditional-discrimination tasks, this demonstrated that restricted attention is not an unmodifiable perceptual characteristic among individuals with developmental disabilities. Recording response topographies with a touch screen was also discovered to be a sensitive measure of stimulus preferences for both groups. Utilizing touch-screen technology may prove to be critical for accurately identifying stimulus preferences and contribute to the understanding and treatment of overselective attention in students with attentional deficits.

Adolescent↗

PubMed2005

Actigraphic recordings in quantification of periodic leg movements during sleep in children.

BACKGROUND: Periodic limb movement disorder (PLMD) has recently emerged as a relatively frequent and markedly underdiagnosed condition in children that induces arousals and sleep fragmentation and leads to poor learning and behavioral problems. Because a cost-effective and widely available alternative to pediatric polysomnography is needed for diagnosis of limb movement disorders, this study sought to examine whether periodic leg movements in children could be reliably identified using recently developed actigraphy software. METHODS: Bilateral actigraphs were worn around the feet by 99 children ages 4-12 years during standard clinical overnight polysomnography, which included bilateral anterior tibial electromyogram (EMG). Left and right leg movements were scored independently for comparison purposes. RESULTS: Agreement between tibial EMG and actigraphy-derived events were initially low, with movement indices being overestimated by actigraphy. This agreement was improved when a correction factor based on the average number of movements during arousals as measured by EMG was applied. However, the correction factor itself was found to differ substantially for patients who were diagnosed with PLMD compared to other patients. CONCLUSIONS: A novel actigraphic approach currently used for detection of PLM events during sleep in adults is insufficiently accurate to permit reliable estimates in children.

Child↗

PubMed1996

Development and implementation of a pain management program.

Perioperative nurses at St Mary's Health Care System, Inc (St Mary's), in Athens, Ga, recognized that some of their postoperative patients did not have an acceptable level of pain control. Based on the Agency for Health Care Policy and Research acute pain management guidelines, they developed and implemented a pain management program. This quality improvement program led to a multidisciplinary effort to maintain each postoperative patient's pain at a level acceptable to that individual. Using a pain level scale, patients are taught to self-report their levels of pain so that medication can be administered appropriately and on a timely basis. A quality improvement team is studying compiled data and anticipates making recommendations about best practices with regard to medication utilization. In September 1995, St Mary's underwent a mock Joint Commission on Accreditation of Healthcare Organizations survey. The surveyors were impressed with the quality and content of the pain management program. Suggestions for other facilities that wish to establish pain management programs are included.

Adaptation, Psychological↗

PubMed1998

Preoperative predictors of cost in Medicare-age patients undergoing coronary artery bypass grafting.

BACKGROUND: Identification of preoperative factors that contribute to the cost of coronary artery bypass grafting could aid in predicting the procedure's expense. In this study, 30 sociodemographic and clinical preoperative factors were examined with "survival analysis" techniques to determine characteristics related to total hospital cost. METHODS: Characteristics of all patients age 65 or older undergoing isolated coronary artery bypass grafting from July 1993 to April 1995 (n = 757) were recorded. Software was developed within the hospital's Transitions Systems, Inc, database to calculate the outcome variable of total cost. Nonparametric methods were used for the univariate analysis of the data, and the Cox proportional hazards model was used for the multivariable analysis, censoring 25 patients who died in the hospital. RESULTS: Median hospital cost from the day of the operation until discharge was $15,198. Median length of stay after the operation was 6 days. Multivariable analysis revealed that age, preoperative renal failure, history of cerebrovascular accident, low ejection fraction, and surgical urgency were independent predictors of total cost. CONCLUSIONS: This study, using an accurate representation of true hospital cost and a modeling technique that accounts for the confounding effect of in-hospital death on cost, provides a template for analysis of cost in other patient groups.

Age Factors↗

PubMed1995

Three-dimensional reconstruction of fibrin clot networks from stereoscopic intermediate voltage electron microscope images and analysis of branching.

Fibrin polymerizes to produce branching fibers forming a three-dimensional network, which has been difficult to visualize by conventional microscopy. Three-dimensional images of whole clots at high resolution were obtained from stereo-pair intermediate-voltage electron micrographs. Computer software was developed to produce three-dimensional reconstructions of the networks in the form of a pattern of links that connect branching junctions. Network parameters were measured and analyzed to characterize the clots quantitatively. Models in which all links were moved to the origin, while preserving their orientation, allowed visualization of some network parameters and facilitated comparison of networks. Fibrin clots formed in three different conditions were analyzed and compared by these methods. Clots formed in 0.20 M saline buffer consist of fibers of uniform size, and most of the branching junctions consist of three links. Fibrin clots formed in 0.05 M saline buffer are made up of very large diameter fiber bundles with far fewer branching junctions and correspondingly longer links. Clots formed in 0.40 M saline buffer consist of very fine fibers with numerous branching junctions and very short links. In summary, the extent of lateral aggregation is directly related to the distance between branching junctions and inversely related to the total number of branching junctions. These observations must be considered in defining possible mechanisms of fibrin branching.

Biophysical Phenomena↗

PubMed2003

Imaging metabolism of phosphatidylinositol 4,5-bisphosphate in T-cell GM1-enriched domains containing Ras proteins.

Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) and Ras proteins are involved in signalling pathways originating at the plasma membrane. The localisation and metabolism of PI(4,5)P(2) was studied in Jurkat T cells using fluorescence microscopic imaging with EGFP-tagged and antibody probes. Software was developed to objectively quantitate colocalisation and was used to show that plasma membrane PI(4,5)P(2) was enriched in lipid raft-containing patches of GM1 ganglioside, formed by crosslinking cholera toxin B-subunit (CT-B). The PI(4,5)P(2) metabolites phosphatidylinositol 3,4,5-trisphosphate and diacylglycerol appeared in plasma membrane CT-B-GM1 patches upon induction of signalling. Transferrin receptor and the CD45 tyrosine phosphatase did not colocalise with CT-B-GM1 patches, whereas the tyrosine kinase Lck, the scaffolding protein LAT, and endogenous Ras proteins did partially colocalise with CT-B-GM1 patches as did transfected EGFP-K-Ras(4B) and EGFP-H-Ras. The results demonstrate that T-cell PI(4,5)P(2) metabolism is occurring in GM1-enriched domains and that Ras proteins are present in these domains in vivo.

Binding Sites↗

PubMed1999

Computer-aided development of a high-performance liquid chromatographic method for the determination of hydroxyanthraquinone derivatives in Chinese herb medicine rhubarb.

With computer simulation predicting separation in reversed-phase gradient elution, a method to separate and determine five hydroxyanthraquinone derivatives having a wide range of polarity in extract of Chinese herbal medicine rhubarb has been developed. The software DryLab was used to model the retention behavior of the compounds as a function of gradient conditions, based on data from two scouting gradient runs. Under the optimized conditions, i.e. column, Zorbax RX-C18, 5 microm, 15x0.46 cm; solvent A, 36 mM triethylamine phosphate (TEAP), pH=2.5; solvent B, ACN; gradient, 36/36/80/80% B at 0/5.5/20.5/25.5 min; flow-rate, 1.00 ml/min; temperature, ambient, the method was successfully applied to monitor the quality of rhubarb from different sources. The effect of sample preparation procedures on extraction efficiency was also examined.

Anthraquinones↗