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At least 991 records · Page 55Linked to original sources

PubMed2004

Comprehensive innovative solution for resident education using the Intranet Journal of Chest Radiology.

RATIONALE AND OBJECTIVES: Because of the rapid increase in clinical workload in academic radiology departments, time for teaching rotating residents is getting more and more limited. As a solution to this problem, we introduced the Intranet Journal of Chest Radiology as a comprehensive innovative tool for assisting resident education. MATERIALS AND METHODS: The Intranet Journal of Chest Radiology is constructed using Microsoft FrontPage version 2002 (Microsoft Corp, Redmond, WA) and is hosted in our departmental web server (Beth Israel Deaconess Medical Center, Boston, MA). The home page of the intranet journal provides access to the main features, "Cases of the Month," "Teaching File," "Selected Articles for Residents," "Lecture Series," and "Current Publications." These features provide quick access to the selected radiology articles, the interesting chest cases, and the lecture series and current publication from the chest section. RESULTS: Our intranet journal has been well utilized for 6 months after its introduction. It enhances residents' interest and motivation to work on case collections, to search and read articles, and to generate interest in research. Frequent updating is necessary for the journal to be kept current, relevant, and well-utilized. CONCLUSION: The intranet journal serves as a comprehensive innovative solution for resident education, providing basic educational resources and opportunities of interactive participation by residents.

Computer Communication Networks↗

PubMed2005

A new method for comprehensive bird's-eye analysis of the surgically excised internal limiting membrane.

PURPOSE: To investigate the role of cells and extracellular matrix on the internal limiting membrane (ILM), we demonstrated a new method for a comprehensive bird's-eye analysis of surgically excised ILM. DESIGN: Laboratory investigation. METHODS: The ILM of an idiopathic epiretinal membrane was fixed and spread out onto a glass slide, using fine needles under a biomicroscope. The expanded ILM was analyzed by light microscopy, immunohistochemistry, and scanning electron microscopy. RESULTS: The excised ILM could be unfolded and spread out as a flat sheet onto the glass slide. Immunohistochemistry revealed that most migrating cells were glial cells. Scanning electronmicroscopy revealed that the vitreous surface of the ILM was smooth, in contrast to the rough retinal surface. The ILM showed abundant cellular migration as a continuous stratified cellular sheet. CONCLUSIONS: This new bird's-eye-view observation of excised ILM enables us to carry out comprehensive analysis of cellular distribution from a temporal and spatial perspective.

Basement Membrane↗

PubMed2004

Preventive-comprehensive assessment (PCA): a new screening method for subclinical cognitive problems.

Physicians often need to be able to assess cognition in a simple way, particularly for screening of subclinical processes in aged people. This paper describes a new, quick test battery called preventive-comprehensive assessment (PCA). It consists of six various testing items (repetition of three words, back-spelling of the word "sport", problem searching ina complex picture, recall of the three words, three progressive colored matrices, clock drawing test), evaluating language, recent memory, executive function, judgment and thinking capacities. The total scores. compared to the normal performance of different age groups, allow us to distinguish between normal and pathological status. If abnormal results are recorded, we need to perform further and deeper neuropsychological investigations, in order to obtain the possibly exact diagnosis. The PCA battery is sensitive and reliable; it can be used in itself, or as a part of a more complex battery of an intense comprehensive evaluation (ICE), carried out in population screening aimed at promoting healthy and active aging.

Age Distribution↗

PubMed2004

Dissociable patterns of brain activity during comprehension of rapid and syntactically complex speech: evidence from fMRI.

Sentence comprehension is a complex task that involves both language-specific processing components and general cognitive resources. Comprehension can be made more difficult by increasing the syntactic complexity or the presentation rate of a sentence, but it is unclear whether the same neural mechanism underlies both of these effects. In the current study, we used event-related functional magnetic resonance imaging (fMRI) to monitor neural activity while participants heard sentences containing a subject-relative or object-relative center-embedded clause presented at three different speech rates. Syntactically complex object-relative sentences activated left inferior frontal cortex across presentation rates, whereas sentences presented at a rapid rate recruited frontal brain regions such as anterior cingulate and premotor cortex, regardless of syntactic complexity. These results suggest that dissociable components of a large-scale neural network support the processing of syntactic complexity and speech presented at a rapid rate during auditory sentence processing.

Adult↗

PubMed2005

Patterns of comprehension performance in agrammatic Broca's aphasia: a test of the Trace Deletion Hypothesis.

We tested the core prediction of the Trace Deletion Hypothesis (TDH) of agrammatic Broca's aphasia, which contends that such patients' comprehension performance is normal for active reversible sentences but at chance level for passive reversible sentences. We analyzed the comprehension performance of 38 Italian Broca's aphasics with verified damage to Broca's area, who completed sentence-to-picture matching tasks using active and passive reversible sentences as stimuli. The results failed to confirm the predictions made by TDH: only a small minority (15%) performed at chance on passive sentences and better than chance on active sentences. Furthermore, the distribution of the 38 subjects' performance on passive sentences differed from that predicted by the TDH since many more subjects performed at better-than-chance levels than expected. We discuss the implication of these results for claims about the distribution of language processing mechanisms in the brain.

Adult↗

PubMed2005

Comprehension of passives in Broca's aphasia.

Drai and Grodzinsky have statistically analyzed a large corpus of data on the comprehension of passives by patients with Broca's aphasia. The data come, according to Drai and Grodzinsky, from binary choice tasks. Among the languages that are analyzed are Dutch and German. Drai and Grodzinsky argue that Dutch and German speaking Broca patients should be relatively good (that is, perform above chance) on comprehension of passive sentences, since in Dutch and German passives the relative order of the object and lexical verb is the underlying order and hence no movement takes place. We will demonstrate that both their linguistic arguments and their selection of Dutch data are invalid.

Aphasia, Broca↗

PubMed2004

A comprehensive approach for drug safety assessment.

A comprehensive, multidisciplinary approach is proposed here for the development of a drug with an acceptable safety profile. Key parameters to be considered for drug safety evaluation based on this comprehensive approach include the following: (1) Pharmacology: Possible toxicity due to drug-target interactions, including interactions with unintended molecular targets, or with molecular targets in unintended organs. (2) Chemistry: Chemical scaffolding and side-chains with safety concerns. (3) Toxicology: Toxicity in animals in vivo, and in relevant animal and human cells in culture. (4) Drug metabolism and pharmacokinetics: Safety concerns due to toxification or detoxification, organ distribution, clearance and pharmacokinetic drug-drug interactions. (5) RISK FACTORS: Physiological, environmental and genetic factors that may enhance a patient's susceptibility. It is proposed that this integrated, multidisciplinary approach to safety evaluation may enhance the accuracy of the prediction of drug safety and thereby the efficiency of drug development.

Animals↗

PubMed2003

Determination of sulfur-containing compounds in diesel oils by comprehensive two-dimensional gas chromatography with a sulfur chemiluminescence detector.

This article reports an analytical method for separating, identifying and quantitating sulfur-containing compounds and their groups in diesel oils (170-400 degrees C) using comprehensive two-dimensional gas chromatography coupled with a sulfur chemiluminescence detector. The identification of target compounds and their groups was based on standard substances, the group separation feature and tile-effect of comprehensive two-dimensional gas chromatography. The quantitative analysis on major sulfur compounds and total sulfur was carried out based on the linear response of sulfur chemiluminescence detector and the internal standards method. The results of total sulfur determination in the samples were compared with those from ASTM D 4294 standard method, the R.S.D. percentage were <6.02%, correctness of this method can meet the industrial requirement. To the end, the method developed was used to investigate the sulfur-containing compounds in different diesel oils, the result shows that the distribution of sulfur-containing compounds in diesel oils from different process units are apparently different. The sulfur compounds in fluid catalytic cracking (FCC), residuum fluid catalytic cracking (RFCC) diesel oils mainly exist in the form of alkyl-substituted dibenzothiophenes that add up to about 40-50% of the total sulfur, while this number is only 6-8 and 20-28% in visbreaking (VB) and delayed-coking (DC) diesel oils, respectively.

Chromatography, Gas↗

PubMed2004

Quantitation of suspected allergens in fragrances part II. Evaluation of comprehensive gas chromatography-conventional mass spectrometry.

The European legislation requires that fragranced products are evaluated for their content in 24 compounds that are suspected to be skin sensitizers. Their quantitation in fragrance concentrates may not be achieved with GC-flame ionization detection (FID), due to the complexity of these mixtures and even comprehensive GC-FID does not provide sufficient resolution. This paper reports the first example of quantitation based on the hyphenation of comprehensive GC with a low-cost quadrupole MS. A detection frequency of 30.7 Hz can be obtained by monitoring a single ion. This allows a satisfactory evaluation of the area sum over the 2-3 modulations of a given compound and linear calibration curves are obtained. Analyses are completed within 35 min.

Allergens↗

PubMed2004

Comprehensive two-dimensional separations of complex mixtures using reversed-phase reversed-phase liquid chromatography.

A comprehensive two-dimensional reversed-phase reversed-phase liquid chromatographic system for the separation of a complex mixture of oligostyrenes was developed using results from a previous theoretical assessment of the informational similarity, percent synentropy, orthogonality and peak capacity of hypothetically coupled systems. The degree of sample attribute order in the first separation dimension was also used in the development of the experimental two-dimensional system. A C18(methanol)/CCZ(acetonitrile) two-dimensional system was chosen for the comprehensive analysis of the oligostyrene mixtures because this system had the lowest solute crowding, highest orthogonality and was observed to have order with respect to a sample attribute in the first separation dimension. The separations achieved were in full agreement with the results from information theory and (a geometric approach to) factor analysis assessments. High sampling rates in the first liquid chromatographic dimension were shown to be impossible or inefficient when the peak capacity and separation time of the second dimension was high or when the aim of the exercise was to isolate individual sample constituents in high yield.

Chromatography, Liquid↗

PubMed2004

Group-type characterisation of mineral oil samples by two-dimensional comprehensive normal-phase liquid chromatography-gas chromatography with time-of-flight mass spectrometric detection.

Normal-phase liquid chromatography (NPLC) and capillary gas chromatography (GC) are complementary techniques, which makes them ideally suited for hyphenated and comprehensive coupling. In this work, an LC and a GC equipped with a time-of-flight mass spectrometer were on-line and comprehensively coupled (LC x GC-ToF MS) for the analysis of mineral oil samples. Classes of compounds present in the oil like paraffins, mono-aromatic and multi-aromatic compounds were separated by normal-phase LC. with a subsequent boiling-point separation within each class by means of GC. Sub-groups present in each class of compounds were distinguished by selecting their unique masses.

Gas Chromatography-Mass Spectrometry↗

PubMed2005

The chemometric resolution and quantification of overlapped peaks form comprehensive two-dimensional liquid chromatography.

The chemometric resolution and quantification of overlapped peaks from comprehensive two-dimensional (2D) liquid chromatography (LCxLC) data are demonstrated. The LCxLC data is produced from an in-house LCxLC analyzer that couples an anion-exchange column via a multi-port valve with a reversed-phase column connected to a UV absorbance detector. Three test mixtures, each containing a target analyte, are subjected to partial LCxLC separations to simulate likely cases of signal overlap. The resulting unresolved target-analyte signals are then analyzed by the standard-addition method and two chemometric methods. The LCxLC analyses of a test mixture and its corresponding standard-addition mixture results in two data matrices, one for each mixture. The stacking of these two data matrices produces a data structure that can then be analyzed by trilinear chemometric methods. One method, the generalized rank annihilation method (GRAM), uses a non-iterative eigenvalue-based approach to mathematically resolve overlapped trilinear signals. The other method, parallel factor analysis (PARAFAC), uses an iterative approach to resolve trilinear signals by the optimization of initial estimates using alternating least squares and signal constraints. In this paper, GRAM followed by PARAFAC analysis is shown to produce better qualitative and quantitative results than using each method separately. For instance, for all three test mixtures, the GRAM-PARAFAC approach improved quantitative accuracy by at least a factor of 4 and quantitative precision by more than 2 when compared to GRAM alone. This paper also introduces a new means of correcting run-to-run retention time shifts in comprehensive 2D chromatographic data.

Benzoic Acid↗

PubMed2005

Silver-ion reversed-phase comprehensive two-dimensional liquid chromatography combined with mass spectrometric detection in lipidic food analysis.

The triacylglycerol (TAG) profiles present in real world lipidic samples are usually quite complex and, as such, monodimensional high-performance liquid chromatographic (HPLC) techniques are inadequate when challenged with such matrices. In this respect, the complementary use of silver-ion (Ag) and non-aqueous (NA) reversed-phase (RP) HPLC can be exploited if thorough TAG separations are required. The present investigation reports the employment of a newly developed comprehensive LC (LC x LC) system, based on the different separation mechanisms of the aforementioned techniques, and applied to a rice oil sample. The approach was successful in the separation of a high number of solutes, otherwise unachievable through monodimensional LC. Furthermore, the use of atmospheric pressure chemical ionization mass spectrometry (APCI-MS), as detection system, provided a third analytical dimension boosting the identification power of the comprehensive chromatographic method.

Chromatography, High Pressure Liquid↗

PubMed2005

Comprehensive two-dimensional liquid chromatography with on-line Fourier-transform-infrared-spectroscopy detection for the characterization of copolymers.

The on-line coupling of comprehensive two-dimensional liquid chromatography (liquid chromatography x size-exclusion chromatography, LC x SEC) and infrared (IR) spectroscopy has been realized by means of an IR flow cell. The system has been assessed by the functional-group analysis of a series of styrene-methylacrylate (SMA) copolymers with varying styrene content. Ultraviolet (UV) detection was used as a detection technique to verify the detection with IR. The LC x SEC-IR functional-group contour plots (comprehensive chromatograms) obtained for styrene were in agreement with the contour plots constructed from the UV signal. In addition, contour plots can be obtained from non-UV-active groups. One such plot, for the carbonyl-stretching vibration of methylacrylate (MA), is shown. Selective detection of MA proved possible using flow cell IR detection. The combination of the contour plots for styrene and MA allowed a full characterization of the copolymer and it was revealed that the present series of SMA copolymers exhibited homogeneous chemical-composition distributions (CCDs). In addition, commercially available fast-SEC columns have been assessed in this study with respect to their potential to serve as second-dimension separation columns.

Acrylates↗

PubMed2005

Comprehensive two-dimensional liquid chromatography combined with mass spectrometric detection in the analyses of triacylglycerols in natural lipidic matrixes.

Triacylglycerols (TAGs), the major components in fats and oils, are a good example of natural complex mixtures. The best technique for the separation of such samples is certainly high performance liquid chromatography (HPLC). Monodimensional HPLC separations are often not sufficient to resolve all the components of interest. The present investigation reports the employment of a comprehensive LC system, based on the different separation mechanisms of silver ion (Ag) and non-aqueous reversed phase (RP) HPLC, used respectively in the first and second dimension, and applied to the analysis of plant-derived natural lipidic matrixes. The results obtained show that the approach enables both the separation of a high number of components and the attainment of structural information due to the formation of group-type patterns on the bidimensional (2D) plane. The employment of atmospheric pressure chemical ionisation (APCI) mass spectrometry as detection system was of substantial support for reliable TAG assignment, thus increasing the identification power of this comprehensive chromatographic approach.

Automation↗

PubMed2006

Separation of technical 4-nonylphenols and their biodegradation products by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry.

Comprehensive two-dimensional gas chromatography (GC x GC) coupled to time-of-flight mass spectrometry (TOF-MS) was applied to improve the separation of 4-nonylphenol isomers and their biodegradation products. The structurally similar nonylphenol isomers were separated by combining a 30 m long semi-polar column and a short polar capillary. Both were coupled via a custom-made liquid nitrogen cryogenic modulator. The advanced GC resolution of coeluting isomers, additionally supported by fast scanning TOF-MS, provided clearer, non-interfered mass spectra of individual isomers. Thus, identification of components is facilitated as shown for isomeric 4-nonylphenols and metabolites of their biodegradation by Clavariopsis aquatica, an aquatic fungus. GC x GC-TOF-MS analysis enabled the separation of about 40 alkylphenol isomers included in technical 4-nonylphenol. During biodegradation the variety of emerging compounds increased with longer reaction time. The comprehensive analysis indicated a broad spectrum of hydroxylated, carboxylated nonylphenolisomers and additionally, chlorinated aromatic compounds produced and released from the fungal culture.

Biodegradation, Environmental↗

PubMed2006

Off-line comprehensive two-dimensional high-performance liquid chromatography system with size exclusion column and reverse phase column for separation of complex traditional Chinese medicine Qingkailing injection.

A comprehensive two-dimensional liquid chromatography system was constructed on the combination of size exclusion chromatography (SEC) and reverse phase liquid chromatography (RPLC). The first dimension used a SEC column with 300 mm x 8mm i.d., packed with Toyopearl HW-40S. The column was eluted with 0.05 mol/l Tris-HCl (pH 6.9) at a flow rate of 0.4 ml/min. The second dimension used a RPLC column with 100 mm x 4.6mm i.d., which was operated in gradient form at a flow rate of 1.0 ml/min. An automatic switching valve was used to collect the effluent of the SEC column every 3 min, and the effluent was automatically injected into the RPLC column. Mass spectrometer was used for peak identification. This system was used to separate Qingkailing injection, a traditional Chinese medicine (TCM). The result showed that the total peak capacity of this system could reach 1134 and the qualitative analysis of seven chemical components of the Qingkailing injection was accomplished by this system. The results show that comprehensive two-dimensional liquid chromatography system is of great importance and high value in the separation of complex TCM.

Chromatography, High Pressure Liquid↗

PubMed2006

A theoretical basis for parameter selection and instrument design in comprehensive size-exclusion chromatography x liquid chromatography.

A novel approach for the selection of the operational parameters (linear velocity, column length) for a comprehensive 2D-LC system is discussed. Starting point for the calculations is a given second dimension ((2)D) separation and a desired peak capacity for the 2D system. Using the theory developed here the optimum settings for the first dimension ((1)D) column can be derived. Theory clearly indicates that the choice of the (1)D conditions is basically limited to just one set of column lengths and linear velocities. The new method is tested on a comprehensive two-dimensional liquid chromatography system which uses size-exclusion chromatography (SEC) followed by reversed phase liquid chromatography (RPLC). A novel LC/LC interface, using a six-port valve rather than storage loops, joins the two chromatographic dimensions. From a theoretical comparison of continuous low flow and stop-flow operation the latter method was found to be an attractive mode of interfacing. The common idea that stop-flow operation results in additional band broadening is shown to be incorrect. The new interface design operated in the stop-flow mode permits the use of conventional analytical diameter HPLC columns, 7.8mm for SEC and 4.6mm for RPLC. The reversed phase chromatography utilizes a monolithic C-18 modified silica column, which produces fast and efficient analyses. As test samples complex mixtures of peptides were analyzed.

Chromatography, Gel↗