Modification of the LixV2O5 phase diagram by incorporation of chromium oxide

The structural behaviour of the sol-gel chromium-vanadium mixed oxide Cr_0.11V₂O_5.16 is investigated as electrochemical lithium insertion proceeds. Electrochemically reduced electrodes are examined by XRD over the large Li composition range 0 < x ≤ 2 in Li_xCr_0.11V₂O_5.16. New fingerprints of lithiated phases are obtained in comparison with available data in the Li-V₂O₅ system. It is shown that lithiation produces an ?-related phase over a wide composition range 0.18 ≤ x ≤ 2 whose interlayer distance linearly increases with x which strongly contrasts with the successive appearance of the (α/?), (?/δ), and (δ/γ) wide biphasic regions for the Li_xV₂O₅ system. The existence of shorts chains of CrO₆ octahedra perpendicular to V₂O₅ layers increases the three-dimensional character of the host lattice impeding then too strong deformations to occur. These limited structural changes resulting in a single phase behaviour are discussed in relation with the original and promising electrochemical properties of the sol-gel mixed oxide Cr_0.11V₂O_5.16.     

Gender differences in myocardial blood flow dynamics: lipid profile and hemodynamic effects

OBJECTIVES: The purpose of the study was to compare myocardial blood flow (MBF) in hyperlipidemic postmenopausal women and age-matched hyperlipidemic men, and to analyze the relationship between cholesterol subfractions and myocardial blood flow in men and women. BACKGROUND: Women are protected from coronary artery disease (CAD) events until well after menopause, in part due to gender-specific differences in lipid profiles. METHODS: To examine the effect of these influences on coronary microcirculation, MBF was quantitated with N-13 ammonia/PET (positron emission tomography) at rest and during adenosine hyperemia in 15 women and 15 men, all nondiabetic, who were matched for age and total cholesterol levels (53+/-4 vs. 50+/-8 years, p = NS, 6.44+/-1.1 vs. 6.31+/-0.85 mmol/liter, or 249+/-41 vs. 244+/-33 mg/dl, p = NS). RESULTS: Women had significantly higher high density lipoprotein (HDL) and lower triglyceride (Tg) levels than did men, and they showed significantly higher resting MBF and stress MBF levels. Significant correlations were found between resting and hyperemic MBF and HDL and Tg levels (r = 0.44, p < 0.02 for stress MBF vs. HDL; r = 0.48, p < 0.007 for stress MBF vs. Tg). Gender was the strongest predictor of hyperemic MBF in multivariate analysis. Women responded to adenosine hyperemia with a significantly higher heart rate than did men, and hemodynamic factors correlated significantly with blood flow both at rest and during stress. CONCLUSIONS: These data suggest that the favorable lipid profile seen in women may be associated with preserved maximal blood flow in the myocardium.     

The identification of markers segregating with resistance to Schistosoma mansoni infection in the snail Biomphalaria glabrata

Both snail and parasite genes determine the susceptibility of the snail Biomphalaria glabrata to infection with the trematode Schistosoma mansoni. To identify molecular markers associated with resistance to the parasite in the snail host, we performed genetic crosses between parasite-resistant and -susceptible isogenic snails. Because resistance to infection in adult snails is controlled by a single locus, DNA samples from individual F2 and F1 backcross progeny, segregating for either the resistant or susceptible phenotypes, were pooled (bulked segregant). Genotypes for both parents were determined with 205 arbitrary decamer primers by random amplified polymorphic DNA-PCR. Of the 205 primers, 144 were informative, and the relative allele frequencies between the pools for these primers were determined. Two primers, OPM-04 and OPZ-11, produced fragments in the resistant parent of one cross that were inherited in a dominant fashion in the resistant F2 and backcross-bulked segregant progeny. Subsequent typing of DNA samples of individual progeny snails showed that the 1.2-kb marker amplified by primer OPM-04 and the 1.0-kb marker produced by primer OPZ-11 segregated in the same dominant fashion with the resistant phenotype. Sequence analysis of the 1.2-kb marker showed that it corresponds to a repetitive sequence in the snail genome with no homology to existing DNA sequences in the public databases. Analysis of the 1. 0-kb marker showed that it also corresponds to a repetitive sequence in the B. glabrata genome that contains an imperfect ORF, with homology to retrovirus-related group-specific antigens (gag) polyprotein.     

Skin cancer in Australian heart transplant recipients

OBJECTIVE: To compare results of a specific capacity assessment administered by the treating clinician, and a Standardized Mini-Mental Status Examination (SMMSE), with the results of expert assessments of patient capacity to consent to treatment. DESIGN: Cross-sectional study with independent comparison to expert capacity assessments. SETTING: Inpatient medical wards at an academic secondary and tertiary referral hospital. PARTICIPANTS: One hundred consecutive inpatients facing a decision about a major medical treatment or an invasive medical procedure. Participants either were refusing treatment, or were accepting treatment but were not clearly capable according to the treating clinician. MEASUREMENTS AND MAIN RESULTS: The treating clinician (medical resident or student) conducted a specific capacity assessment on each participant, using a decisional aid called the Aid to Capacity Evaluation. A specific capacity assessment is a semistructured evaluation of the participant's ability to understand relevant information and appreciate reasonably foreseeable consequences with regard to the specific treatment decision. Participants also received a SMMSE administered by a research nurse. Participants then had two independent expert assessments of capacity. If the two expert assessments disagreed, then an independent adjudication panel resolved the disagreement after reviewing videotapes of both expert assessments. Using the two expert assessments and the adjudication panel as the reference standard, we calculated areas under the receiver-operating characteristic curves and likelihood ratios. The areas under the receiver-operating characteristic curves were 0.90 for specific capacity assessment by treating clinician and 0.93 for SMMSE score (2p =.48). For the treating clinician's specific capacity assessment, likelihood ratios for detecting incapacity were as follows: definitely incapable, 20 (95% confidence interval [CI] 3. 6, 120); probably incapable, 6.1 (95% CI 2.6, 15); probably capable, 0.39 (95% CI 0.18, 0.81); and definitely capable, 0.05 (95% CI 0.01, 0.29). For the SMMSE, a score of 0 to 16 had a likelihood ratio of 15 (95% CI 5.3, 44), a score of 17 to 23 had a likelihood ratio of 0. 68 (95% CI 0.35, 1.2), and a score of 24 to 30 had a likelihood ratio of 0.05 (95% CI 0.01, 0.26). CONCLUSIONS: Specific capacity assessments by the treating clinician and SMMSE scores agree closely with results of expert assessments of capacity. Clinicians can use these practical, flexible, and evaluated measures as the initial step in the assessment of patient capacity to consent to treatment.     

Cervical carcinoma: can dynamic contrast-enhanced MR imaging help predict tumor aggressiveness?

PURPOSE: To determine whether fast dynamic contrast agent-enhanced magnetic resonance (MR) imaging can demonstrate tumor aggressiveness of cervical carcinoma in patients who are eligible for surgical treatment. MATERIALS AND METHODS: Dynamic contrast-enhanced MR imaging of cervical carcinoma was performed in 82 consecutive patients with stage I or IIA disease who were referred for radical hysterectomy. The maximum slope and amplitude of dynamic first-pass contrast enhancement were quantified. These parameters were correlated with histologic measures of tumor aggressiveness (tumor invasion depth, pelvic lymph node status). RESULTS: The analysis was based on tumors in 62 patients: 30 aggressive and 32 relatively nonaggressive tumors. Twenty patients were excluded from analysis owing to insufficient surgical data, tumor too small for accurate assessment, or technical problems. There were no significant differences between aggressive and nonaggressive tumors in terms of the first-pass contrast-enhancement parameters of slope (2.0 vs 2.1 arbitrary signal intensity units per second, P > .5) or amplitude (24.8 vs 27.8 arbitrary units, P > .2). CONCLUSION: Dynamic contrast-enhanced MR imaging does not facilitate differentiation between aggressive and nonaggressive tumors and therefore has no clinical role in assisting in treatment decisions in patients who are candidates for radical hysterectomy.