Neuronal imaging with ultrahigh dynamic range multiphoton microscopy

Multiphoton microscopes are hampered by limited dynamic range, preventing weak sample features from being detected in the presence of strong features, or preventing the capture of unpredictable bursts in sample strength. We present a digital electronic add-on technique that vastly improves the dynamic range of a multiphoton microscope while limiting potential photodamage. The add-on provides real-time negative feedback to regulate the laser power delivered to the sample, and a log representation of the sample strength to accommodate ultrahigh dynamic range without loss of information. No microscope hardware modifications are required, making the technique readily compatible with commercial instruments. Benefits are shown in both structural and in-vivo functional mouse brain imaging applications.R21 EY027549 - NEI NIH HH

Orbital frustration at the origin of the magnetic behavior in LiNiO2

We report on the ESR, magnetization and magnetic susceptibility measurements performed over a large temperature range, from 1.5 to 750 K, on high-quality stoichiometric LiNiO2. We find that this compound displays two distinct temperature regions where its magnetic behavior is anomalous. With the help of a statistical model based on the Kugel'-Khomskii Hamiltonian, we show that below T_of ~ 400 K, an orbitally-frustrated state characteristic of the triangular lattice is established. This then gives a solution to the long-standing controversial problem of the magnetic behavior in LiNiO2.Comment: 5 pages, 5 figures, RevTex, accepted in PR

Planar spin exchange in LiNiO_2

We study the planar spin exchange couplings in LiNiO2 using a perturbative approach. We show that the inclusion of the trigonal crystal field splitting at the Oxygen sites leads to the appearance of antiferromagnetic exchange integrals in deviation from the Goodenough-Kanamori-Anderson rules for this 90 degree bond. That gives a microscopic foundation for the recently observed coexistence of ferromagnetic and antiferromagnetic couplings in the orbitally-frustrated state of LiNiO2. (F. Reynaud et al, Phys. Rev. Lett. 86, 3638 (2001))Comment: latex, revtex4, 6 pages, 3 figure

Twin polaritons in semiconductor microcavities

The quantum correlations between the beams generated by polariton pair scattering in a semiconductor microcavity above the parametric oscillation threshold are computed analytically. The influence of various parameters like the cavity-exciton detuning, the intensity mismatch between the signal and idler beams and the amount of spurious noise is analyzed. We show that very strong quantum correlations between the signal and idler polaritons can be achieved. The quantum effects on the outgoing light fields are strongly reduced due to the large mismatch in the coupling of the signal and idler polaritons to the external photons

Progressive scoliosis in central core disease

Central core disease (CCD) is a rare congenital myopathy with autosomal dominant inheritance. Here, we report on two cases of progressive scoliosis in CCD, pointing out the value of a muscle biopsy to establish the correct diagnosis. The first case involves a 13-year-old boy with severe progressive scoliosis and joint contractures. The patient was initially diagnosed with arthropgryposis multiplex congenita. The second case involves a 45-year-old man with severe scoliosis that had slowly progressed over the years. Both patients suffered from unexplained muscle weakness and severe restriction of pulmonary function. The correct diagnoses were established through muscle biopsies taken from the paravertebral musculature during scoliosis surgery. Correction of the spinal deformities was achieved through posterior instrumentation in both patients, with prior anterior release in one patient. Although scoliosis is a common feature in CCD, the correct diagnosis can be missed in scoliosis patients. Therefore, we recommend a muscle biopsy in patients with scoliosis, unexplained muscle weakness and multiple joint problem

Clinical Disease Severity of Respiratory Viral Co-Infection versus Single Viral Infection: A Systematic Review and Meta-Analysis.

BACKGROUND: Results from cohort studies evaluating the severity of respiratory viral co-infections are conflicting. We conducted a systematic review and meta-analysis to assess the clinical severity of viral co-infections as compared to single viral respiratory infections. METHODS: We searched electronic databases and other sources for studies published up to January 28, 2013. We included observational studies on inpatients with respiratory illnesses comparing the clinical severity of viral co-infections to single viral infections as detected by molecular assays. The primary outcome reflecting clinical disease severity was length of hospital stay (LOS). A random-effects model was used to conduct the meta-analyses. RESULTS: Twenty-one studies involving 4,280 patients were included. The overall quality of evidence applying the GRADE approach ranged from moderate for oxygen requirements to low for all other outcomes. No significant differences in length of hospital stay (LOS) (mean difference (MD) -0.20 days, 95% CI -0.94, 0.53, p = 0.59), or mortality (RR 2.44, 95% CI 0.86, 6.91, p = 0.09) were documented in subjects with viral co-infections compared to those with a single viral infection. There was no evidence for differences in effects across age subgroups in post hoc analyses with the exception of the higher mortality in preschool children (RR 9.82, 95% CI 3.09, 31.20, p<0.001) with viral co-infection as compared to other age groups (I2 for subgroup analysis 64%, p = 0.04). CONCLUSIONS: No differences in clinical disease severity between viral co-infections and single respiratory infections were documented. The suggested increased risk of mortality observed amongst children with viral co-infections requires further investigation

Stronger correlation between antibiotic use and the incidence of Clostridium difficile determined by culture results instead of faecal toxin detection only

The detection of Clostridium difficile in previous studies evaluating antibiotic use as a risk factor was limited to toxin assay tests. The reported associations may have been misleading due to the low sensitivity of toxin assay tests compared to culture results. Antibiotic use and the incidence of C. difficile of 19 units (wards) over 5years were analysed. Stool samples were tested for toxin A/B and cultured. The correlation of antibiotic use with the incidence of C. difficile determined by culture results was compared to the correlation determined by toxin assay results. Additionally, single antibiotics were analysed as risk factors. Of 5,772 faecal samples tested for C. difficile, 154 single-first cases were detected by the toxin assay and 251 additional single-first cases by culture. Antibiotic use was a significantly stronger risk factor in the correlation based on the culture results (R 2 = 0.63) versus toxin assay results (R 2 = 0.40). Multivariate analysis did not improve the correlation significantly and only the group of broad-spectrum beta-lactams was identified as an independent risk factor. The correlation between antibiotic use and C. difficile incidence rates significantly improves if detection is not limited to faecal toxin assays. Therefore, antibiotic pressure was previously underestimated as a risk facto

How much money can be saved by applying intravenous antibiotics once instead of several times a day?

Background: The preparation, administration and monitoring of intravenous (IV) applications are time consuming and require human resources. We estimated the potential time and cost savings by replacing antibiotics given 3-4 times daily with antibiotics with similar spectrum and efficacy given once daily. Methods: The savings of indirect costs were estimated based on the antibiotic consumption data of a two-year period (i.e. 2007 and 2008), a nurse's mean workload per application and the average nurse's salary in Switzerland. Results: The consumption of IV antibiotics in 2007 and 2008 at the University Hospital of Basel was 29.0 and 32.2 defined daily doses (DDD) per 100 patient days, respectively. Nurses spent an estimated 13,786h on the application of the estimated 82,715 does of IV antibiotics. A total of 56,404 applications or nursing staff time costs of 338,436 Swiss Francs (CHF; 236,669 €), equal to 16% of the overall costs spent on purchasing antibiotics in the year 2008, may have been saved by switching multiple-dose antibiotics to a hypothetical once-daily antibiotic. Including disposable materials, 21% or 456,884 CHF (319,499 €) could be saved annually (purchase costs not taken into account). Conclusion: We found a potential cost saving of 21% of the purchase costs in a 750-bed institution. Hence, indirect costs should be included in the calculation of the total cost for the application of broad-spectrum IV antibiotics. Switching from a 3-4 times daily application to a once-daily antibiotic should be considered if a once-daily antibiotic is deemed equally effective and has a similar spectru

Herd effect from influenza vaccination in non-healthcare settings: a systematic review of randomised controlled trials and observational studies.

Influenza vaccination programmes are assumed to have a herd effect and protect contacts of vaccinated persons from influenza virus infection. We searched MEDLINE, EMBASE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Global Health and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to March 2014 for studies assessing the protective effect of influenza vaccination vs no vaccination on influenza virus infections in contacts. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using a random-effects model. Of 43,082 screened articles, nine randomised controlled trials (RCTs) and four observational studies were eligible. Among the RCTs, no statistically significant herd effect on the occurrence of influenza in contacts could be found (OR: 0.62; 95% CI: 0.34-1.12). The one RCT conducted in a community setting, however, showed a significant effect (OR: 0.39; 95% CI: 0.26-0.57), as did the observational studies (OR: 0.57; 95% CI: 0.43-0.77). We found only a few studies that quantified the herd effect of vaccination, all studies except one were conducted in children, and the overall evidence was graded as low. The evidence is too limited to conclude in what setting(s) a herd effect may or may not be achieved