Static NLO susceptibilities: testing approximation schemes against exact results

The reliability of the approximations commonly adopted in the calculation of static optical (hyper)polarizabilities is tested against exact results obtained for an interesting toy-model. The model accounts for the principal features of typical nonlinear organic materials with mobile electrons strongly coupled to molecular vibrations. The approximations introduced in sum over states and finite field schemes are analyzed in detail. Both the Born-Oppenheimer and the clamped nucleus approximations turn out to be safe for molecules, whereas for donor-acceptor charge transfer complexes deviations from adiabaticity are expected. In the regime of low vibrational frequency, static susceptibilities are strongly dominated by the successive derivatives of the potential energy and large vibrational contributions to hyperpolarizabilities are found. In this regime anharmonic corrections to hyperpolarizabilities are very large, and the harmonic approximation, exact for the linear polarizability, turns out totally inadequate for nonlinear responses. With increasing phonon frequency the role of vibrations smoothly decreases, until, in the antiadiabatic (infinite vibrational frequency) regime, vibrations do not contribute anymore to static susceptibilities, and the purely electronic responses are regained.Comment: 9 pages, including 3 figure

Premature Birth with Complicated Perinatal Course Delaying Diagnosis of Prader-Willi Syndrome

Prader-Willi syndrome in the newborn is essentially characterized by marked hypotonia, feeding difficulties, hypogonadism, and possible characteristic facial features. However, diagnosis at this age may be particularly difficult, and dysmorphic features may be subtle or absent. Prematurity can furthermore delay clinical features recognition and typical complications due to preterm birth may contribute to divert the diagnosis. We describe a preterm baby with a complicated perinatal course later diagnosed as PWS

Clinical pharmacokinetics of tramadol and main metabolites in horses undergoing orchiectomy.

Tramadol is a synthetic codeine analogue used as an analgesic in human and veterinary medicine. It is not approved for use in horses, but could represent a valid tool for pain treatment in this species.The serum pharmacokinetic profile and urinary excretion of tramadol and its metabolites (O-desmethyltramadol [M1], N-desmethyltramadol [M2] and N,O-desmethyltramadol [M5]) was investigated in a multidrug anaesthetic and analgesic approach for orchiectomy in horses. The evaluation of the degree of cardiovascular stability, the intraoperative effect and postoperative analgesia obtained by the visual analogue scale are also reported. Animal and methods: Tramadol (4 mg/kg BW) was administered intravenously to eight male yearlings as a bolus over 60 seconds, 5 min after intubation and 15 min prior to surgery. Drug quantification was performed in serum and urine for tramadol, M1, M2 and M5 by high-performance liquid chromatography with fluorimetric detection.Mean tramadol concentration was 14.87 ± 11.14 μg/mL at 0.08 h, and 0.05 ± 0.06 μg/mL at 10 h. Serum concentrations of M1 and M2 metabolites were quite limited. For M1 and M2, median maximum concentration (Cmax) and time to achieve maximum concentration (Tmax) were 0.05 μg/mL and 0.75 h, and 0.08 μg/mL and 2 h, respectively; M5 was never detected. In urine, tramadol was the most recovered compound, followed by M1, M2 and M5.Showing no adverse events and based on the kinetic behaviour, pre-operative tramadol IV at a dose of 4 mg/kg BW might be useful and safe as analgesic in horses undergoing surgery

Serratia marcescens outbreak in a neonatal intensive care unit: crucial role of implementing hand hygiene among external consultants.

BACKGROUND: Serratia marcescens represents an important pathogen involved in hospital acquired infections. Outbreaks are frequently reported and are difficult to eradicate. The aim of this study is to describe an outbreak of Serratia marcescens occurred from May to November 2012 in a neonatal intensive care unit, to discuss the control measures adopted, addressing the role of molecular biology in routine investigations during the outbreak. METHODS: After an outbreak of Serratia marcescens involving 14 neonates, all admitted patients were screened for rectal and ocular carriage every two weeks. Extensive environmental sampling procedure and hand sampling of the staff were performed. Antimicrobial susceptibility pattern and molecular analysis of isolates were carried out. Effective hand hygiene measures involving all the external consultants has been implemented. Colonized and infected babies were cohorted. Dedicated staff was established to care for the colonized or infected babies. RESULTS: During the surveillance, 65 newborns were sampled obtaining 297 ocular and rectal swabs in five times. Thirty-four Serratia marcescens isolates were collected: 11 out of 34 strains were isolated from eyes, being the remaining 23 isolated from rectal swabs. Two patients presented symptomatic conjunctivitis. Environmental and hand sampling resulted negative. During the fifth sampling procedure no colonized or infected patients have been identified. Two different clones have been identified. CONCLUSIONS: Ocular and rectal colonization played an important role in spread of infections. Implementation of infection control measures, involving also external specialists, allowed to control a serious Serratia marcescens outbreak in a neonatal intensive care unit

Compliance of clinical microbiology laboratories with recommendations for the diagnosis of bloodstream infections

In 2014, the Italian Working Group for Infections in Critically Ill Patient of the Italian Association of Clinical Microbiologists updated the recommendations for the diagnostic workflow for bloodstream infections (BSI). Two years after publication, a nationwide survey was conducted to assess the compliance with the updated recommendations by clinical microbiology laboratories. A total of 168 microbiologists from 168 laboratories, serving 204 acute care hospitals and postacute care facilities, were interviewed during the period January\u2013October 2016 using a questionnaire consisting of nineteen questions which assessed the level of adherence to various recommendations. The most critical issues were as follows: (a) The number of sets of blood cultures (BC) per 1,000 hospitalization days was acceptable in only 11% of laboratories; (b) the minority of laboratories (42%) was able to monitor whether BCs were over or under-inoculated; (c) among the laboratories monitoring BC contamination (80%), the rate of contaminated samples was acceptable in only 12% of cases;(d) the Gram-staining results were reported within 1 hr since BC positivity in less than 50% of laboratories. By contrast, most laboratories received vials within 2\u20134 hr from withdrawal (65%) and incubated vials as soon as they were received in the laboratory (95%). The study revealed that compliance with the recommendations is still partial. Further surveys will be needed to monitor the situation in the future

De novo unbalanced translocations have a complex history/aetiology

We investigated 52 cases of de novo unbalanced translocations, consisting in a terminally deleted or inverted-duplicated deleted (inv-dup del) 46th chromosome to which the distal portion of another chromosome or its opposite end was transposed. Array CGH, whole-genome sequencing, qPCR, FISH, and trio genotyping were applied. A biparental origin of the deletion and duplication was detected in 6 cases, whereas in 46, both imbalances have the same parental origin. Moreover, the duplicated region was of maternal origin in more than half of the cases, with 25% of them showing two maternal and one paternal haplotype. In all these cases, maternal age was increased. These findings indicate that the primary driver for the occurrence of the de novo unbalanced translocations is a maternal meiotic non-disjunction, followed by partial trisomy rescue of the supernumerary chromosome present in the trisomic zygote. In contrast, asymmetric breakage of a dicentric chromosome, originated either at the meiosis or postzygotically, in which the two resulting chromosomes, one being deleted and the other one inv-dup del, are repaired by telomere capture, appears at the basis of all inv-dup del translocations. Notably, this mechanism also fits with the origin of some simple translocations in which the duplicated region was of paternal origin. In all cases, the signature at the translocation junctions was that of non-homologous end joining (NHEJ) rather than non-allelic homologous recombination (NAHR). Our data imply that there is no risk of recurrence in the following pregnancies for any of the de novo unbalanced translocations we discuss here