Can domain-based local pair natural orbitals approaches accurately predict phosphorescence energies?

Since the discovery of the peculiar conducting and optical properties of aromatics, many efforts have been made to characterize and predict their phosphorescence. This physical process is exploited in modern Organic Emitting Light Diodes (OLEDs), and it is also one of the processes decreasing the efficiency of Dye-sensitized solar cells (DSSCs). Herein, we propose a computational strategy for the accurate calculation of singlet-triplet gaps of aromatic compounds, which provides results that are in excellent agreement with available experimental data. Our approach relies on the domain-based local pair natural orbital (DLPNO) variant of the "gold standard" CCSD(T) method. The convergence of our results with respect to the key technical parameters of the calculation, such as the basis set used, the approximations employed in the perturbative triples correction, and the dimension of the PNOs space, was thoroughly discussed.

Spin Density Topology.

Despite its role in spin density functional theory and it being the basic observable for describing and understanding magnetic phenomena, few studies have appeared on the electron spin density subtleties thus far. A systematic full topological analysis of this function is lacking, seemingly in contrast to the blossoming in the last 20 years of many studies on the topological features of other scalar fields of chemical interest. We aim to fill this gap by unveiling the kind of information hidden in the spin density distribution that only its topology can disclose. The significance of the spin density critical points, the 18 different ways in which they can be realized and the peculiar topological constraints on their number and kind, arising from the presence of positive and negative spin density regions, is addressed. The notion of molecular spin graphs, spin maxima (minima) joining paths, spin basins and of their valence is introduced. We show that two kinds of structures are associated with a spin-polarized molecule: the usual one, defined through the electron density gradient, and the magnetic structure, defined through the spin density gradient and composed in general by at least two independent spin graphs, related to spin density maxima and minima. Several descriptors, such as the spin polarization index, are introduced to characterize the properties of spin density critical points and basins. The study on the general features of the spin density topology is followed by the specific example of the water molecule in the 3B1 triplet state, using spin density distributions of increasing accuracy.

Reducing mortality in cardiac surgery with levosimendan: a meta-analysis of randomized controlled trials.

OBJECTIVES: The authors performed a meta-analysis to evaluate whether levosimendan is associated with improved survival in patients undergoing cardiac surgery. DESIGN: A meta-analysis. SETTING: Hospitals. PARTICIPANTS: A total of 440 patients from 10 randomized controlled studies were included in the analysis. INTERVENTIONS: None. MEASURMENTS AND MAIN RESULTS: Four investigators independently searched BioMedCentral and PubMed. Inclusion criteria were random allocation to treatment, comparison of levosimendan versus control, and cardiac surgery patients. Exclusion criteria were duplicate publications, nonhuman experimental studies, and no mortality data. The primary endpoint was postoperative mortality. Levosimendan was associated with a significant reduction in postoperative mortality (11/235 [4.7%] in the levosimendan group v 26/205 [12.7%] in the control arm, odds ratio = 0.35 [0.18-0.71], p for effect = 0.003, p for heterogeneity = 0.22, I(2) = 27.4% with 440 patients included), cardiac troponin release, and atrial fibrillation. No difference was found in terms of myocardial infarction, acute renal failure, time on mechanical ventilation, intensive care unit, and hospital stay. CONCLUSIONS: Levosimendan has cardioprotective effects that could result in a reduced postoperative mortality. A large randomized controlled study is warranted in this setting.

Levosimendan reduces cardiac troponin release after cardiac surgery: a meta-analysis of randomized controlled studies.

OBJECTIVES: The authors performed a meta-analysis to investigate the effects of levosimendan in cardiac surgery. Inotropic drugs have never shown beneficial effects on outcome in randomized controlled studies, with the possible exception of levosimendan. DESIGN: A meta-analysis. SETTING: Hospitals. PARTICIPANTS: A total of 139 patients from 5 randomized controlled studies were included in the analysis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Four investigators independently searched BioMedCentral and PubMed. Inclusion criteria were random allocation to treatment, and comparison of levosimendan versus control performed on cardiac surgery patients. Exclusion criteria were duplicate publications, nonhuman experimental studies, and no outcome data. The endpoint was postoperative cardiac troponin release. Levosimendan was associated with a significant reduction in cardiac troponin peak release (weighted mean difference = 2.5 ng/dL [-3.86, -1.14], p = 0.0003) and in time to hospital discharge (weighted mean difference = -1.38 days [-2.78, 0.03], p = 0.05). No other relevant outcome (mortality, myocardial infarction, atrial fibrillation, time on mechanical ventilation, and intensive care unit stay) was improved in those patients receiving levosimendan. CONCLUSIONS: Levosimendan has cardioprotective effects, resulting in reduced postoperative cardiac troponin release.

Role of cardiac biomarkers (troponin I and CK-MB) as predictors of quality of life and long-term outcome after cardiac surgery.

Perioperative and postoperative morbidity and mortality associated with cardiac surgery affect both the outcome and quality of life. Markers such as troponin effectively predict short-term outcome. In a prospective cohort study in a University Hospital we assessed the role of cardiac biomarkers, also as predictors of long-term outcome and life quality after cardiac surgery with a three-year follow-up after conventional heart surgery. Patients were interviewed via phone calls with a structured questionnaire examining general health, functional status, activities of daily living, perception of life quality and need for hospital readmission. Descriptive statistics and multivariate analysis were performed. Out of 252 consecutive patients, 8 (3.2%) died at the three years follow up: 7 for cardiac complications and 1 for cancer. Thirty-six patients (13.5%) had hospital readmission for cardiac causes (mostly for atrial fibrillation or other arrhythmias (9.3%), but none needed cardiac surgical reintervention; 21 patients (7.9%) were hospitalised for non-cardiac causes. No limitation in function activities of daily living was reported by most patients (94%), 92% perceived their general health as excellent, very good or good and none considered it insufficient; 80% were NYHA I, 17% NYHA II, 3% NYHA III and none NYHA IV. Multivariate analysis indicated preoperative treatment with digitalis or nitrates, and postoperative cardiac biomarkers release was independently associated to death. Elevated cardiac biomarker release and length of hospital stay were the only postoperative independent predictors of death in this study.

Soy protein formulas in children: no hormonal effects in long-term feeding.

Recently, the finding of high plasma concentration of phyto-oestrogens in soy protein formula (SPF) fed children has focused scientific attention on the phyto-oestrogens (isoflavones genistein, daidzein, and their glycosides) contained in SPFs. The aim of this study was to evaluate some hormonal and metabolic effects of long-term (more than 6 months) SPF feeding. We enrolled 48 children, mean age 37 months (range 7-96 months), 27 males and 21 females. All children underwent physical examination. Bone age, urinary markers of bone metabolism, serum levels of bone alkaline phosphatase, osteocalcin, 17beta-oestradiol, and intact parathyroid hormone were measured. Eighteen healthy children represented the control group. No abnormalities were observed in auxological parameters; none of the enrolled girls showed signs/symptoms of precocious puberty and none of the boys presented gynecomastia; bone age was within the normal range. The serum level of bone alkaline phosphatase, osteocalcin, 17beta-oestradiol, and intact parathyroid hormone, and the urinary levels of the markers of bone metabolism were all within normal values. We conclude that long-term feeding with SPFs in early life does not seem to produce oestrogen-like hormonal effects.