Observation of electromagnetically induced transparency and slow light in the dark state--bright state basis.

The quantum coherence phenomenon of electromagnetically induced transparency (EIT) is observed in a three-level system composed of an excited state and two coherent superpositions of the two ground-state levels. This peculiar ground state basis is composed of the so-called bright and dark states of the same atomic system in a standard coherent population trapping configuration. The characteristics of EIT, namely, width of the transmission window and reduced group velocity of light, in this unusual basis, are theoretically and experimentally investigated and are shown to be essentially identical to those of standard EIT in the same system.

Localization and delocalization of energy in a Peyrard-Bishop chain.

This paper studies energy localization conditions in lattices of the type proposed by Peyrard and Bishop. Homogeneous and inhomogeneous lattices are analyzed and the role of interfaces in the latter is emphasized. Simulations allowed us to identify critical energy values for the existence of localization. After a certain energy value, it is possible to observe the loss of energy localization along the chain.

Energy localization in the phi4 oscillator chain.

We study energy localization in a finite one-dimensional phi(4) oscillator chain with initial energy in a single oscillator of the chain. We numerically calculate the effective number of degrees of freedom sharing the energy on the lattice as a function of time. We find that for energies smaller than a critical value, energy equipartition among the oscillators is reached in a relatively short time. On the other hand, above the critical energy, a decreasing number of particles sharing the energy is observed. We give an estimate of the effective number of degrees of freedom as a function of the energy. Our results suggest that localization is due to the appearance, above threshold, of a breather-like structure. Analytic arguments are given, based on the averaging theory and the analysis of a discrete nonlinear Schrödinger equation approximating the dynamics, to support and explain the numerical results.

Late effects in patients with Fanconi anemia following allogeneic hematopoietic stem cell transplantation from alternative donors.

Hematopoietic stem cell transplantation (HSCT) is curative for hematological manifestations of Fanconi anemia (FA). We performed a retrospective analysis of 22 patients with FA and aplastic anemia, myelodysplastic syndrome or acute myelogenous leukemia who underwent a HSCT at Memorial Sloan Kettering Cancer Center and survived at least 1 year post HSCT. Patients underwent either a TBI- (N=18) or busulfan- (N=4) based cytoreduction followed by T-cell-depleted transplants from alternative donors. Twenty patients were alive at time of the study with a 5- and 10-year overall survival of 100 and 84% and no evidence of chronic GvHD. Among the 18 patients receiving a TBI-based regimen, 11 (61%) had persistent hemochromatosis, 4 (22%) developed hypothyroidism, 7 (39%) had insulin resistance and 5 (27%) developed hypertriglyceridemia after transplant. Eleven of 16 evaluable patients (68%), receiving TBI, developed gonadal dysfunction. Two patients who received a TBI-based regimen died of squamous cell carcinoma. One patient developed hemochromatosis, hypothyroidism and gonadal dysfunction after busulfan-based cytoreduction. TBI appears to be a risk factor for malignant and endocrine late effects in the FA host. Multidisciplinary follow-up of patients with FA (including cancer screening) is essential for early detection and management of late complications, and improving long-term outcomes.

Charge effect in the interaction of doxorubicin and derivatives with polydeoxynucleotides.

The equilibrium interaction of doxorubicin and its N-acetyl derivative with a series of purine-pyrimidine alternating polydeoxynucleotides has been studied through spectrofluorometry to assess the relevance of the electrostatic contribution to DNA intercalation. The results have shown that: (a) the suppression of the positive charge on the aminosugar has: (I) a profound negative effect on the free energy of intercalation, as expected, and (II) a negligible influence on the base specificity, which supports the notion of an essentially electrostatic effect of N-acetylation on intercalation; (b) a reasonably good accord with the demands of a polyelectrolytic model, due to Friedman and Manning, is found.

Initial reliability and validity of a new retrospective measure of child abuse and neglect.

OBJECTIVE: This report presents initial findings on the reliability and validity of a new retrospective measure of child abuse and neglect, the Childhood Trauma Questionnaire. METHOD: Two hundred eighty-six drug- or alcohol-dependent patients were given the Childhood Trauma Questionnaire as part of a larger test battery, and 40 of these patients were given the questionnaire again after an interval of 2 to 6 months. Sixty-eight of the patients were also given a structured interview for child abuse and neglect, the Childhood Trauma Interview, that was developed by the authors. RESULTS: Principal-components analysis of responses on the Childhood Trauma Questionnaire yielded four rotated orthogonal factors: physical and emotional abuse, emotional neglect, sexual abuse, and physical neglect. Cronbach's alpha for the factors ranged from 0.79 to 0.94, indicating high internal consistency. The Childhood Trauma Questionnaire also demonstrated good test-retest reliability over a 2- to 6-month interval (intraclass correlation = 0.88), as well as convergence with the Childhood Trauma Interview, indicating that patients' reports of child abuse and neglect based on the Childhood Trauma Questionnaire were highly stable, both over time and across type of instruments. CONCLUSIONS: These findings provide strong initial support for the reliability and validity of the Childhood Trauma Questionnaire.

Nonvolumetric methods of detecting impaired intracranial compliance or reactivity: pulse width and wave form analysis.

The authors have attempted to find a clinically reliable method of measuring intracranial pressure (ICP) compliance or reactivity that does not require volumetric manipulation. An analysis was undertaken of ICP, pulse widths and of the presence or absence of B waves, both experimentally in dogs and clinically in postoperative human patients. In both dogs and humans, ICP pulse width generally increased with increasing ICP and with increasing intracranial mass, and definitely increased with systolic arterial blood pressure. Nonetheless, ICP pulse width commonly failed to increase with increasing cerebral reactivity, and low ICP pulse width measurements were at times recorded in distinctly pathological situations. From the clinical study it was found that B waves were encountered more commonly in patients with increased ICP or increased ICP pulse width. However, the correlation between B waves alone or in combination with increased ICP or ICP pulse width and quantitative measurements of ICP reactivity was not significant. Mean reactivity and the range of reactivity measurements were almost identical in patient groups with and without B waves. For the time being the "ICP reserve test" remains the most accurate, the safest, and the most clinically useful method of quantitating ICP reserve.

Clinical effectiveness of a pancreatic enzyme supplement.

In 23 adult patients with pancreatic insufficiency, we evaluated the efficacy of a pancreatic enzyme delivered as pH-sensitive enteric-coated pancreatic lipase microspheres, and compared it with placebo and other available enzyme supplements. In a short-term study, fecal fat was 23.5 +/- 7 g/day with the microspheres, compared with 29.9 +/- 8 with other supplements, providing fat utilization of 76 +/- 7% versus 63 +/- 10% (p less than 0.05). Microspheres reduced daily stool frequency to 1.9 movements from 4.3 on other enzymes (p less than 0.01). These results were obtained with an average intake of 10 microsphere capsules/day. In a year-long study of 22 patients, an average weight gain of 4.0 +/- 1.1 kg was observed associated with return of near-normal social and work life-style in previously housebound patients.

Increased calcium affinity of a fucosylated chondroitin sulfate from sea cucumber.

Calcium binding and charge distribution on a fucosylated chondroitin sulfate and a standard chondroitin 6-sulfate have been studied using a metallochromic indicator and conductimetric titrations. The fucosylated chondroitin sulfate has a approximately 5-fold greater affinity for calcium ions than the standard chondroitin 6-sulfate. Possibly, this increased affinity for calcium ions is due to the branches on the fucosylated chondroitin sulfate, since the calcium affinity of an unbranched, sulfated fucan is similar to that of the standard chondroitin 6-sulfate. More charged groups per disaccharide unit (and a shorter distance between these groups) also distinguish the fucosylated chondroitin sulfate from standard chondroitin 6-sulfate. Comparison between native and chemically modified (desulfated or carboxyl-reduced) polysaccharides suggests that the sulfate esters are responsible for the increased charge density of the fucosylated chondroitin sulfate and that the presence of the fucose branches does not alter the length of the repetitive units which compose the central core of chondroitin from sea cucumber. These results are consistent with the chemical studies of these two polysaccharides.

Conformational features of galacturonans. I. Structure and energy minimization of charged and uncharged galacturonan dimeric units.

Structural parameters (e.g. the geometry, partial charges and dipole moment) of the alpha-D-galacturonic residue have been calculated by using semi-empirical quantum mechanical methods on several combinations of either the uncharged or charged forms, GalAH and GalA-, respectively. Three residue types have been explored: (i) the isolated residue, termed GEO1 and GEO1C for GalAH and GalA-, respectively; (ii) the residue with a methyl group attached to the O4 and O1 positions (GEO2 and GEO2C); and (iii) the internal residue in a trimer, e.g. GalAH-GalAH-GalAH or the corresponding fully charged version (GEO3 and GEO3C). The presence of a charged group in the galacturonate residue and the distribution of the excess negative charge on the molecule lead to significant differences in the structural parameters in comparison with those of the uncharged galacturonic residue. These perceptible differences in internal coordinates of GalAH and GalA- residues appear to play a major role in the delimitation of the conformational space that is accessible to the dimers, as clearly seen by inspection of the conformational maps. Although the overall features seem alike, the maps show that the position of the minimum and the shape of the lower energy region significantly change if one or both residues in the dimer are charged. The relevance of these results for the conformational properties of polygalacturonate chains is discussed elsewhere (Ruggiero et al. Int. J. Biol. Macromol. 1995, 17, 213-218).

Conformational features of galacturonans. II. Configurational statistics of pectic polymers.

The unperturbed dimensions of poly-alpha-D-galacturonic acid (PGA) as a function of the degree of polymerization (n) and degree of ionization (%GalA-) have been determined by molecular mechanics and Monte Carlo methods. Chain extensions appear to depend substantially on contributions arising from local redistributions of charge on charged and uncharged galacturonic acid residues. Inclusion of methyl-esterified galacturonic acid units results in increased chain extensions. Incorporation of alpha-(1-->2)-L-rhamnose units causes abrupt changes in chain propagation and a reduction in calculated chain extension.

A model coupling vibrational and rotational motion for the DNA molecule.

We investigate a mechanical model for the DNA molecule using an extension of the Peyrard and Bishop model. In the present model, there are two chains of oscillators linked by a Morse potential, which represent the hydrogen bonds. The rotational and vibrational motions of each base pair are considered and the coupling for these motions are introduced by a nonlinear combination of them in the Morse potential. In this context, thermodynamics and structural properties are discussed.

The popular approach to women's health issues: a content analysis of women's magazines in the 1970's.

This study reports the results of a content analysis of three "established" and three "new" popular women's magazines. A sample of 203 articles/features on women's health topics was drawn from a stratified systematic random sample of 157 issues over a ten year period. The two types of magazines were compared for amount of coverage given to women's health issues and specific health-related themes. Health themes covered in the magazines were also compared with statistical data on serious health conditions experienced by women, and leading causes of mortality and morbidity. Established magazines were found to give more overall coverage to women's health than did the new magazines, particularly focusing on diet and exercise. However, little attention was given to the serious health problems women actually experience. Implications of results are discussed and directions for future research outlined.

Insomnia, fatigue, anxiety, depression, and quality of life of cancer patients undergoing chemotherapy.

The purposes of this study were to examine: (a) the relationships between the symptoms of insomnia and fatigue and the psychological factors of anxiety and depression, and; (b) the relationships between these psychological and symptom variables and quality of life in cancer patients who were receiving chemotherapy. The Theory of Unpleasant Symptoms was the framework for the study. A descriptive correlational design was used in a secondary analysis of data obtained from a sample of 263 cancer patients who were undergoing chemotherapy. Insomnia, fatigue, depression, and anxiety were positively correlated with one another (r = .26 to r = .69, p < .001) and negatively correlated with quality of life (r = -.28 to r = -.63, p < .001). Women had more anxiety and fatigue and poorer quality of life than did men. Older age was associated with better quality of life and less insomnia, fatigue, anxiety, and depression. Multiple regression analysis revealed that the symptoms and psychological variables explained 47% of the variance in quality of life, with the largest proportion of the variance explained by depression. Fatigue and insomnia explained only 4% of the variance in quality of life in excess of that contributed by the psychological factors. Although overall depression levels were low in this sample, these findings suggest that insomnia and fatigue are related to depression and that depression is more closely associated with quality of life than are insomnia and fatigue.

On the interaction of small molecules with hemoglobin: orientational effects of hydration layers in protein crystal.

The spin label TEMPO does not show a binding to hemoglobin molecule in solution. In the crystal however the spin label is bound and a considerable anisotropy in the ESR spectra is observed similar to that with covalent spin labeling. Since TEMPO is a small spherical molecule the anisotropy should be a consequence of the ordering in the crystal packing observed for the hydration layers. Besides the anisotropic sites (one per asymmetric unit) an isotropic signal is apparent. The population of these sites is sensitive to the temperature and above around 30 degrees C a transition is observed of the label from the anisotropic site to the isotropic one. This is consistent with a change in the hydration structure above this temperature so that the spin label is sensitive to the reorganization of water or crystallization. Results of simulations based on the relaxation theory in liquids are compared for different hemoglobin physical states: crystal, powder and solution. It is shown that the ESR parameters obtained in the crystal are very different from those used for spectral stimulation at low temperature.

Monocytes and macrophages synthesize and secrete thrombospondin.

Thrombospondin, one of the major glycoproteins released from alpha-granules of thrombin-stimulated platelets, is a disulfide-linked trimer of 160,000-dalton subunits. Cultured human monocytes secreted thrombospondin (determined by an enzyme-linked immunosorbent assay) into the culture medium in a time-dependent manner (1.45 micrograms/10(6) cells/24 hr); secretion was totally blocked by cycloheximide (1 microgram/mL). 35S-thrombospondin was isolated from 35S-methionine-labeled human monocyte postculture medium with rabbit polyclonal anti-thrombospondin coupled to protein A-Sepharose. The immunoisolated 35S-thrombospondin migrated in sodium dodecyl sulfate-polyacrylamide gels after reduction with a molecular weight of 159,000. Similar results were obtained using mouse resident peritoneal macrophages. Elicited peritoneal macrophages harvested from mice pretreated with endotoxin, casein, or thioglycollate secreted much less thrombospondin than did resident macrophages harvested from control mice. Thus, monocytes and macrophages from two different species synthesize and secrete thrombospondin, and the rate of synthesis of thrombospondin appears to depend on the state of activation of the cells.

Microbial manganese reduction mediated by bacterial strains isolated from aquifer sediments.

One hundred and five strains isolated from aquifer sediments andEscherichia coli ML30S were tested for their ability to reduce manganese oxides. Eighty-two strains, includingE. coli, reduced manganese. In most cases the bacterial activity decreased the pH and Eh below 6.75 and 350 mV, respectively, enhancing a spontaneous and nonspecific reduction of manganese. However, for 12 strains the reduction was specifically catalyzed by bacteria; the high pH and Eh values would not permit a spontaneous reduction of manganese. Some of the most active strains were identified as genera common in soils and waters, i.e.,Pseudomonas, Bacillus, Corynebacterium, andAcinetobacter. Two strains were studied in detail. One of the strains, identified asPseudomonas fluorescens, required contact between the cells and the manganese oxides for reduction to occur. The reduction was inhibited by 15 mM of sodium azide. The other strain, identified asAcinetobacter johnsonii, catalyzed manganese reduction by an inductive and dialyzable substance which was excreted by the bacteria. The mechanism involved has not been previously demonstrated.

Central venous catheterization for parenteral nutrition.

To define the risks associated with central venous catheterization for total parenteral nutrition (TPN) 3291 patient days of this therapy, delivered by an established nutrition support team, were evaluated. One hundred and seventy-five catheters placed in 104 patients were reviewed over an 18 month period. Positive cultures were reported on 11 cannulae for a 6.4% incidence of colonization; five catheters (2.8%) were considered septic. Pleural or mediastinal complications of subclavian or internal jugular venipuncture occurred in eight patients (4.8%). Misdirection of the catheter tip occurred in 11.5% of insertions. Five patients (4.8%) had clinically apparent thrombosis in the superior vena cava, innominate and/or subclavian veins during hospitalization; four others had evidence of thrombosis at autopsy examination, giving an incidence of 8.7% in the entire series. No death directly resulted from the use of this therapy. Compliance with a rigid protocol by an experienced team can allow safe and effective use of central venous catheters and parenteral nutrition therapy.