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At least 163 records · Page 9Linked to original sources
PubMed2001

Shift in diurnal feeding patterns in nursing home residents with Alzheimer's disease.

BACKGROUND: Individuals with Alzheimer's disease (AD) are highly susceptible to weight loss and malnutrition, which, to date, have not been associated with decreased food consumption. The current study examined food intake patterns and how they change in relation to body mass index (BMI), behavioral function, and cognitive status in institutionalized seniors with AD. METHODS: Twenty-one consecutive days of investigator-weighed food intake collections were conducted on 25 subjects with likely AD residing at a home for the aged. All subjects maintained the ability to self-feed. RESULTS: Eighty-eight percent of participants did not meet targeted energy needs, including an estimated 37% prevalence of protein inadequacy. Subjects with increased behavioral difficulties, based on the London Psychogeriatric Rating Scale, had reduced meal-related intakes that were highly associated with decreased energy consumption at dinner. With behavioral changes, particularly increased mental disorganization and confusion, there was a shift in circadian eating patterns such that the greatest proportion of daily energy was consumed at breakfast. Individuals with low BMIs tended to be those with more behavioral difficulties, such that BMI was also associated with the shift in overall eating patterns. CONCLUSIONS: Changes in behavioral function in seniors with AD result in a circadian shift in intake patterns with the preponderance of calories consumed at breakfast in those with increased behavioral difficulties. This shift in eating patterns associates both with poor overall intake and poor BMI.

Aged↗
PubMedDate not supplied

The feasibility of the detection and quantitation of beta-adrenergic blockers by solid-phase extraction and subsequent derivatization with methaneboronic acid.

Urine specimens containing 11 common beta blockers were processed using solid-phase extraction technology to extract the drugs from the urine matrix, then converted to their cyclic methaneboronates by treatment with methaneboronic acid in ethyl acetate. The compounds tested included acebutolol, atenolol, alprenolol, bisoprolol, betaxolol, carteolol, penbutolol, propranolol, pindolol, timolol, nadolol, sotalol, labetolol, metoprolol, and oxprenolol. The extraction efficiencies were greater than 90% for all drugs tested. The cyclic methaneboronates formed by this procedure generally possessed good chromatographic properties. The mass spectral behavior of the methaneboronates was excellent, with all compounds containing several high mass fragments and every tested compound possessing a unique mass spectrum.

Adrenergic beta-Antagonists↗
PubMed2005

Characteristic fragmentation behavior of some glucuronide-type triterpenoid saponins using electrospray ionization tandem mass spectrometry.

The fragmentation behavior of some glucuronide-type triterpenoid saponins from Symplocos chinensis, and their analogues escin Ia and Ib, were investigated by positive ion electrospray ionization tandem mass spectrometry using a quadrupole linear ion trap mass spectrometer. The fragmentation patterns of these saponins significantly changed in accordance with structural variations in the glucuronyl residue of the oligosaccharide chain. It was found that the carboxyl group and hydroxyl group at the C-3' position of the glucuronyl residue were the key sites for determining the fragmentation behavior of these compounds. When the carboxyl group was esterified, only the C(2alpha) ion, and no B(2alpha) ion, and cationized aglycone were observed. When the hydroxyl group at C-3' was acylated, the inherent cross-ring cleavage was hindered. However, glycosidic cleavages always occurred, regardless of the crucial structural variations. The results of the present studies can benefit the determination of trace triterpenoid saponins of this type in crude plant extracts, and also provide background information to aid the structural investigations of similar glycoconjugates.

Escin↗
PubMed2006

Systematic review of the effectiveness of mass communication programs to change HIV/AIDS-related behaviors in developing countries.

This review systematically examined the effectiveness of 24 mass media interventions on changing human immunodeficiency virus (HIV)-related knowledge, attitudes and behaviors. The intervention studies were published from 1990 through 2004, reported data from developing countries and compared outcomes using (i) pre- and post-intervention data, (ii) treatment versus control (comparison) groups or (iii) post-intervention data across levels of exposure. The most frequently reported outcomes were condom use (17 studies) and knowledge of modes of HIV transmission (15), followed by reduction in high-risk sexual behavior (eight), perceived risk of contracting HIV/acquired immunodeficiency syndrome (AIDS) (six), interpersonal communication about AIDS or condom use (six), self-efficacy to negotiate condom use (four) and abstaining from sexual relations (three). The results yielded mixed results, and where statistically significant, the effect size was small to moderate (in some cases as low as 1-2% point increase). On two of the seven outcomes, at least half of the studies did show a positive impact of the mass media: knowledge of HIV transmission and reduction in high-risk sexual behavior. Further rigorous evaluation on comprehensive programs is required to provide a more definitive answer to the question of media effects on HIV/AIDS-related behavior in developing countries.

Communication↗
PubMed1987

Extrapolation from rat studies with environmental tobacco smoke (ETS) to humans: comparison of particle mass deposition and of clearance behavior of ETS compounds.

The relative deposition of inhaled heterodisperse particles of the size of environmental tobacco smoke (ETS, mass median aerodynamic diameter 0.2 micron, geometric standard deviation 1.5) is about the same in the tracheobronchial tree and is lower in the pulmonary region of the rat than in the same regions of humans. However, model calculations show that per cm2 of surface area the deposition rate of ETS particle mass shows a doubling in rats as compared to humans in the transitional zone of the lung, i.e., airway generations 16-20. Within the human airways, mainstream smoke particles are deposited to a higher degree in generations 2-5 than in the transitional zone, whereas the opposite applies to ETS particles. Significantly higher pulmonary retention in man than in rats of inhaled ETS particles and their constituents (e.g. cadmium) leads to additional differences in the dose accumulating in the lung over time. Such differences in deposition and retention characteristics of inhaled ETS have to be considered when extrapolating results from rat studies to humans.

Aerosols↗
PubMed2006

Accurate mass measurement using Fourier transform ion cyclotron resonance mass spectrometry for structure elucidation of designer drug analogs of tadalafil, vardenafil and sildenafil in herbal and pharmaceutical matrices.

Phosphodiesterase type 5 (PDE-5) inhibitors are a class of drugs used primarily in the treatment of erectile dysfunction. The Food and Drug Administration (FDA) approved PDE-5 inhibitors include sildenafil citrate, vardenafil hydrochloride and tadalafil. In this study, accurate mass measurements were made by electrospray ionization (ESI) using Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) to elucidate the structures of sildenafil, tadalafil and vardenafil analogs that were found in products marketed as dietary supplements. Initial detection of these analogs was accomplished through routine screening of suspect samples by liquid chromatography/electrospray ionization multi-stage mass spectrometry (LC/ESI-MS(n)) on a low-resolution ion trap instrument. The chromatographic behavior and mass spectrometric fragmentation patterns observed were often similar to those observed for FDA approved PDE-5 inhibitors. The mass accuracy and resolving power associated with FTICRMS allows for the determination of elemental compositions. Elucidation of the product ion structures for the analogs was accomplished through the use of accurate mass measurements with the aid of Mass Frontier software (version 4.0). Using FTICRMS, accurate masses with measurement errors averaging <0.4 ppm were achieved, allowing assignment of one possible elemental formula to each fragment ion. The mass measurement errors associated with [M + H](+) for the analogs aminotadalafil, piperidino vardenafil, hydroxyacetildenafil and piperidino acetildenafil were 0.1, 0.0, 0.1 and 0.5 ppm, respectively. Based on the accuracy of the measurements, structural assignments could be made with a high degree of confidence.

Benzodioxoles↗
PubMed2006

A comparative study of limited-angle cone-beam reconstruction methods for breast tomosynthesis.

Digital tomosynthesis mammography (DTM) is a promising new modality for breast cancer detection. In DTM, projection-view images are acquired at a limited number of angles over a limited angular range and the imaged volume is reconstructed from the two-dimensional projections, thus providing three-dimensional structural information of the breast tissue. In this work, we investigated three representative reconstruction methods for this limited-angle cone-beam tomographic problem, including the backprojection (BP) method, the simultaneous algebraic reconstruction technique (SART) and the maximum likelihood method with the convex algorithm (ML-convex). The SART and ML-convex methods were both initialized with BP results to achieve efficient reconstruction. A second generation GE prototype tomosynthesis mammography system with a stationary digital detector was used for image acquisition. Projection-view images were acquired from 21 angles in 3 degrees increments over a +/- 30 degrees angular range. We used an American College of Radiology phantom and designed three additional phantoms to evaluate the image quality and reconstruction artifacts. In addition to visual comparison of the reconstructed images of different phantom sets, we employed the contrast-to-noise ratio (CNR), a line profile of features, an artifact spread function (ASF), a relative noise power spectrum (NPS), and a line object spread function (LOSF) to quantitatively evaluate the reconstruction results. It was found that for the phantoms with homogeneous background, the BP method resulted in less noisy tomosynthesized images and higher CNR values for masses than the SART and ML-convex methods. However, the two iterative methods provided greater contrast enhancement for both masses and calcification, sharper LOSF, and reduced interplane blurring and artifacts with better ASF behaviors for masses. For a contrast-detail phantom with heterogeneous tissue-mimicking background, the BP method had strong blurring artifacts along the x-ray source motion direction that obscured the contrast-detail objects, while the other two methods can remove the superimposed breast structures and significantly improve object conspicuity. With a properly selected relaxation parameter, the SART method with one iteration can provide tomosynthesized images comparable to those obtained from the ML-convex method with seven iterations, when BP results were used as initialization for both methods.

Algorithms↗
PubMed2002

Study of structural characteristic features of phenanthriondolizidine alkaloids by fast atom bombardment with tandem mass spectrometry.

The mass spectrometric behavior of phenanthroindolizidine alkaloids has been investigated in detail by positive ion fast atom bombardment tandem mass spectrometry (FAB-MS/MS) combined with collision-induced dissociation (CID). The fragmentation has been correlated with the skeleton structure and positions of substituents. The product ions arising from retro-Diels-Alder cleavages differ clearly for compounds with different skeletons. The substituents at C-14 were observed to markedly influence the fragmentation pathway of [M + H](+) ions. A diversity of dissociation behavior initiated by the variation of substituents on the aromatic ring was also observed in the CID spectra. Product ions resulting from loss of CH(4) were obtained for compounds in which both C-6 and C-7 are occupied by methoxy groups. FAB-MS/MS spectra can reflect the connection between the fragmentation behavior and structural features of these phenanthroindolizidine alkaloids rapidly and effectively, and should prove to be a powerful method to determine the structures of related compounds.

Alkaloids↗
PubMed2001

Mass transport characteristics and chromatographic behavior of preparative electrochromatography on hydroxyapatite.

Introducing an electric field into chromatography on hydroxyapatite (HAP) was attempted in order to enhance mass transfer and separation performance. A membrane spaced multicompartment electrolyzer was developed for electrochromatography on HAP. The high performance of liquid transport by electroosmotic flux was identified and described in terms of dynamic electroosmotic pressure. The application of the electric field resulted in an improved adsorption of bovine serum albumin as shown by the breakthrough curve as function of the electric field. An improved elution was also obtained in the presence of the electric field. The results show that electroosmosis is a powerful tool of liquid transport and dispersion in a packed bed of fine particles and has potential in the large-scale chromatography of biological molecules.

Adsorption↗
PubMed2003

Dynamic behavior of ozonation with pollutant in a countercurrent bubble column with oxygen mass transfer.

The dynamic behavior of ozonation with pollutants in a countercurrent bubble column is studied for the model establishment. Bubble columns have been widely used for an ozonation system in the plants and laboratories. In addition, a countercurrent bubble column has been commonly recommended than a cocurrent one because it has a higher ozone transfer efficiency. Therefore, the investigation of this paper focuses on the countercurrent bubble column. As an ozonation process starts, the gas mixture of ozone and oxygen is introduced into the bottom of a column, and then transferred into the liquid. The pollutants in the wastewater are eliminated subsequently via oxidation by the dissolved ozone. There certainly exists a temporary and unsteady period before the ozonation system reaches steady state. However, available ozonation models employed to describe ozone and pollutant profiles have commonly been developed for steady state. The treating qualities of wastewater in the early stage of ozonation are usually not predicted, and the time required for the steady-state establishment remains to be determined. Moreover, oxygen mass transfer is usually neglected in previous ozonation models so that the increase of dissolved oxygen is uncertain. These information is desirable for the proper design and operation of ozonation system in a bubble column. Thus, the aim of this study is to model and investigate the dynamic processes of ozonation with pollutants including oxygen mass transfer. The dynamic axial dispersion model proposed is employed to predict the variation of the ozone, pollutant, and oxygen concentrations profiles. The validity of the model was demonstrated by comparing the predicted results with the experimental data. The o-cresol was chosen as the model pollutant. The temporal concentration variations of the residual o-cresol and dissolved oxygen in the effluent liquid, and the off-gas ozone in the free volume were measured accordingly. Furthermore, the variation of the enhancement factor of ozone and the amount of off-gas were predicted. Note that it usually needs 2-5 hydraulic retention times to approach steady state under the conditions of this study. Further, the effects of dimensionless system parameters on the performance of the ozonation processes are examined. As a result, the proposed dynamic model of ozonation with pollutants is useful for proper prediction of the variables of an ozonation system in a countercurrent bubble column.

Gases↗
PubMed1985

Eating behavior, personality traits and body mass in women.

In an exploratory study in women, the relationships between scales of emotional eating, external eating, and restrained eating, and body mass index (BMI = weight/height2) were studied, as well as the interrelationships between these three eating behavior components. In addition, the relationships between the three eating behavior scales and 19 personality scales were examined. Finally, differences between obese and latent obese women with respect to eating behavior and personality were investigated. Significant relationships were found between BMI and emotional eating, and between BMI and external eating/perceived hunger, but not between BMI and Restrained Eating. Also, restrained eating was found not to be related to the other two eating behavior components. Of the three eating behavior components, emotional eating was shown to have the clearest relationships with a number of personality traits. No difference was observed between the eating behavior of latent obese and obese women, but these groups differed as to a number of personality traits. These results are discussed in terms of consequences for prevalent theories on restrained, external, and emotional eating.

Adult↗