On a graph related to permutability in finite groups

This paper has been published in Annali di Matematica Pura ed Applicata. Series IV, 189(4):567-570 (2010). Copyright 2010 by Springer-Verlag. The final publication is available at www.springerlink.com. http://link.springer.com/article/10.1007%2Fs10231-009-0124-7 http://dx.doi.org/10.1007/s10231-009-0124-7For a finite group G we define the graph $\Gamma(G)$ to be the graph whose vertices are the conjugacy classes of cyclic subgroups of G and two conjugacy classes $\{\mathcal {A}, \mathcal {B}\}$ are joined by an edge if for some $\{A \in \mathcal {A},\, B \in \mathcal {B}\, A\}$ and B permute. We characterise those groups G for which $\Gamma(G)$ is complete.This paper has been suported by the research grants MTM2007-68010-C03-02 from MEC (Spain) and FEDER (European Union) and GV/2007/243 from Generalitat (Valencian Community).http://dx.doi.org/10.1007/s10231-009-0124-7Ballester Bolinches, A.; Cossey, J.; Esteban Romero, R. (2010). On a graph related to permutability in finite groups. Annali di Matematica Pura ed Applicata. 4(189). doi:10.1007/s10231-009-0124-74189Abe S., Iiyori N.: A generalization of prime graphs of finite groups. Hokkaido Math. J. 29(2), 391–407 (2000)Agrawal R.K.: Finite groups whose subnormal subgroups permute with all Sylow subgroups. Proc. Am. Math. Soc. 47(1), 77–83 (1975)Alejandre M.J., Ballester-Bolinches A., Pedraza-Aguilera M.C.: Finite soluble groups with permutable subnormal subgroups. J. Algebra 240(2), 705–722 (2001)Ballester-Bolinches A., Esteban-Romero R.: Sylow permutable subnormal subgroups of finite groups. J. Algebra 251(2), 727–738 (2002)Cooper C.D.H.: Power automorphisms of a group. Math. Z. 107, 335–356 (1968)Herzog M., Longobardi P., Maj M.: On a commuting graph on conjugacy classes of groups. Commun. Algebra 37(10), 3369–3387 (2009)Huppert B.: Endliche Gruppen I, vol. 134 of Grund. Math. Wiss. Springer, Berlin (1967)Longobardi P.: Gruppi finite a fattoriali modulari. Note Math. II, 73–100 (1982)Neumann B.: A problem of Paul Erdős on groups. J. Austral. Math. Soc. Ser. A 21, 467–472 (1976)Ore O.: Contributions to the theory of groups of finite order. Duke Math. J. 5, 431–460 (1939)Schmidt R.: Subgroup lattices of groups. De Gruyter Expositions in Mathematics, vol. 14. Walter de Gruyter, Berlin (1994)Zacher G.: I gruppi risolubli finiti in cui i sottogruppi di composizione coincidono con i sottogrupi quasi-normali. Atti Accad. Naz. Lincei Rend. cl. Sci. Fis. Mat. Natur. 37(8), 150–154 (1964

Risk Factors for Necrotizing Enterocolitis:A Prospective Multicenter Case-Control Study

BACKGROUND: The identification of independent clinical risk factors for necrotizing enterocolitis (NEC) may contribute to early selection of infants at risk, allowing for the development of targeted strategies aimed at the prevention of NEC. OBJECTIVE: The objective of this study was to identify independent risk factors contributing to the development of NEC in a large multicenter cohort. METHODS: This prospective cohort study was performed in 9 neonatal intensive care units. Infants born at a gestational age </=30 weeks were included. Demographic and clinical data were collected daily until day 28 postnatally. Factors predictive of the development of NEC were identified using univariate and multivariable analyses in a 1: 5 matched case-control cohort. RESULTS: In total, 843 infants (56 NEC cases) were included in this study. In the case-control cohort, univariate analysis identified sepsis prior to the onset of NEC and formula feeding to be associated with an increased risk of developing NEC, whereas the administration of antibiotics directly postpartum was inversely associated with NEC. In a multivariable logistic regression model, enteral feeding type and the number of days parenterally fed remained statistically significantly associated with NEC, whereas the administration of antibiotics directly after birth was associated with a lower risk of developing NEC. CONCLUSIONS: Formula feeding and prolonged (duration of) parenteral feeding were associated with an increased risk of NEC. Contrary to expectations, the initiation of treatment with antibiotics within 24 h after birth was inversely associated with NEC

Cerebrospinal Fluid Compartmental Pharmacokinetics of Amikacin in Neonates▿

To describe and investigate the covariate effects of cerebrospinal fluid (CSF) amikacin pharmacokinetics in neonates, CSF samples were prospectively collected from neonates in whom amikacin had been initiated before a diagnostic lumbar puncture was performed. CSF analysis (amikacin concentration, white blood count [WBC], glucose content, and protein concentration) and amikacin therapeutic drug monitoring results (peak and trough concentrations) in serum were recorded. Correlations (Spearman rank) between the CSF amikacin concentration and the CSF WBC and glucose and protein concentration were investigated. There were 44 CSF amikacin concentrations and 83 serum samples available from 43 neonates (mean postmenstrual age, 36 weeks [range, 26 to 41 weeks]; mean weight, 2.43 kg [range, 0.87 to 3.86 kg]). The median time interval between initiation of amikacin administration and CSF sampling was 25 h (range, 2.5 to 93.7 h). The median amikacin concentration in the CSF was 1.08 mg/liter (range, 0.34 to 2.65 mg/liter), and the mean trough and peak amikacin concentrations in serum were 3.8 ± 2.5 mg/liter and 35.7 ± 5.9 mg/liter, respectively. A correlation between CSF amikacin and CSF protein contents (P < 0.01, r = 0.41, 95% confidence interval = 0.13 to 0.63) but not between CSF WBC and CSF glucose was documented. A two-compartment (central and CSF) linear disposition model was used to estimate population pharmacokinetics. The half time for equilibration (Teq) between serum and CSF compartments was used as a measure of blood-brain barrier permeability. The Teq was 7.58 h (coefficient of variation [CV] = 49.1%) with a partition coefficient of 0.103 (CV = 26.4%). There was no relationship between the Teq and CSF WBC, CSF glucose content, or CSF protein content

An open label study to evaluate the single dose pharmacokinetics, safety and tolerability of doripenem in infants less than 12 weeks chronological age

Doripenem, a parenteral carbapenem with broad-spectrum activity against aerobic Gram-negative and Gram-positive and anaerobic pathogens, is currently approved for use in adults in the United States and European Union. Single-dose doripenem pharmacokinetics in 52 infants 4 weeks. Mean Vz was highest in subjects with the earliest gestational age (<32 weeks): 0.564 liter/kg for neonates and 0.548 liter/kg for infants. Single-dose pharmacokinetics of doripenem administered as a 1-hour infusion in term and preterm infants <12 weeks in chronological age were similar to what has been observed in neonates and very young infants with other carbapenems. Single-dose doripenem was generally safe and well tolerated. (This study has been registered with ClinicalTrials.gov under registration no. NCT01381848 and with EudraCT under registration no. 2009-014387-20.).status: publishe

Systematic review finds risk of bias and applicability concerns for models predicting central line-associated bloodstream infection (CLA-BSI)

OBJECTIVE: To systematically review the risk of bias and applicability of published prediction models for risk of central line-associated bloodstream infection (CLA-BSI) in hospitalized patients. STUDY DESIGN AND SETTING: Systematic review of literature in PubMed, Embase, Web of Science Core Collection and Scopus up to July 10, 2023. Two authors independently appraised risk models using CHARMS and assessed their risk of bias and applicability using PROBAST. RESULTS: Sixteen studies were included, describing 37 models. When studies presented multiple algorithms, we focused on the model that was selected as the best by the study authors. Eventually we appraised 19 models, among which 15 regression models and 4 machine learning models. All models were at a high risk of bias, primarily due to inappropriate proxy outcomes, predictors that are unavailable at prediction time in clinical practice, inadequate sample size, negligence of missing data, lack of model validation, and absence of calibration assessment. 18 out of 19 models had a high concern for applicability, 1 model had unclear concern for applicability due to incomplete reporting. CONCLUSION: We did not identify a prediction model of potential clinical use. There is a pressing need to develop an applicable model for CLA-BSI