Femtosecond Covariance Spectroscopy

The success of non-linear optics relies largely on pulse-to-pulse consistency. In contrast, covariance based techniques used in photoionization electron spectroscopy and mass spectrometry have shown that wealth of information can be extracted from noise that is lost when averaging multiple measurements. Here, we apply covariance based detection to nonlinear optical spectroscopy, and show that noise in a femtosecond laser is not necessarily a liability to be mitigated, but can act as a unique and powerful asset. As a proof of principle we apply this approach to the process of stimulated Raman scattering in alpha-quartz. Our results demonstrate how nonlinear processes in the sample can encode correlations between the spectral components of ultrashort pulses with uncorrelated stochastic fluctuations. This in turn provides richer information compared to the standard non-linear optics techniques that are based on averages over many repetitions with well-behaved laser pulses. These proof-of-principle results suggest that covariance based nonlinear spectroscopy will improve the applicability of fs non-linear spectroscopy in wavelength ranges where stable, transform limited pulses are not available such as, for example, x-ray free electron lasers which naturally have spectrally noisy pulses ideally suited for this approach

Assessment of a continuous blood gas monitoring system in animals during circulatory stress

<p>Abstract</p> <p>Background</p> <p>The study was aimed to determine the measurement accuracy of The CDI™ blood parameter monitoring system 500 (Terumo Cardiovascular Systems Corporation, Ann Arbor MI) in the real-time continuous measurement of arterial blood gases under different cardiocirculatory stress conditions</p> <p>Methods</p> <p>Inotropic stimulation (Dobutamine 2.5 and 5 μg/kg/min), vasoconstriction (Arginine-vasopressin 4, 8 and 16 IU/h), hemorrhage (-10%, -20%, -35%, and -50% of the theoretical volemia), and volume resuscitation were induced in ten swine (57.4 ± 10.7 Kg).Intermittent blood gas assessments were carried out using a routine gas analyzer at any experimental phase and compared with values obtained at the same time settings during continuous monitoring with CDI™ 500 system. The Bland-Altman analysis was employed.</p> <p>Results</p> <p>Bias and precision for pO₂were - 0.06 kPa and 0.22 kPa, respectively (r²= 0.96); pCO₂- 0.02 kPa and 0.15 kPa, respectively; pH -0.001 and 0.01 units, respectively ( r²= 0.96). The analysis showed very good agreement for SO₂(bias 0.04,precision 0.33, r²= 0.95), Base excess (bias 0.04,precision 0.28, r²= 0.98), HCO₃(bias 0.05,precision 0.62, r²= 0.92),hemoglobin (bias 0.02,precision 0.23, r²= 0.96) and K⁺(bias 0.02, precision 0.27, r²= 0.93). The sensor was reliable throughout the experiment during hemodynamic variations.</p> <p>Conclusions</p> <p>Continuous blood gas analysis with the CDI™ 500 system was reliable and it might represent a new useful tool to accurately and timely monitor gas exchange in critically ill patients. Nonetheless, our findings need to be confirmed by larger studies to prove its reliability in the clinical setting.</p

Wayforlight : the Catalogue of European light sources

Wayforlight.eu is the gateway to find-ing the most suitable instruments for experiments with synchrotron, FEL, and laser light sources. The portal's main asset is a de-tailed searchable catalogue of facilities, beam-lines, and instrumentation available at Euro-pean light sources. Thanks to its advanced search tools, a visitor can filter beamlines by scientific discipline, by technique, but also by energy range or sample type

Relationship of thymidylate synthase levels to outcome of malignant pleural mesothelioma patients treated with pemetrexed-based chemotherapy

7508 Background: Pemetrexed has shown activity in malignant pleural mesothelioma (MPM) but scanty data are available on the expression of thymidylate synthase (TS), its most important molecular target. Methods: From a database of 75 non-surgical, chemotherapy-naive MPM patients from our Institution in the period 2004–2008, 50 (male/female: 37/13, median age: 65 years) met the selection criteria i.e. epithelial type, availability of thoracoscopic tissue and outcome data. Pemetrexed was administered as single agent (14/50) or in combination with cisplatin or carboplatin (36/50). Retrospectively TS protein expression levels were evaluated by immunohistochemistry and quantified with H-score method. In addition, mRNA extraction was performed in 23 micro-dissected tissues and TS relative levels quantified by RT-PCR. Survival probability was assessed by Kaplan-Meier method and results compared by log-rank test. Cox multivariate analysis for survival was performed adjusting for clinical-pathological variables. Results: Thirty-two patients had progressive disease and 24 had died at the time of the analysis. Median time to progression (TTP) and median survival time (MST) were 11.6 and 20.9 months, respectively. Median TS H-score value was 90 (5–240). No correlation were found with sex, age, PS, stage and chemotherapy regimen. Patients with high TS H-score (4th quartile) had a significantly shorter MST (13.3 vs 21.1 months, p&lt;0.01) and showed a trend for shorter TTP (8.3 vs 11.9 months, p=0.07). Median TS mRNA level was 1.88 (1–3.7 unit-less ratio) and a significant correlation between mRNA and protein expression (RS=0.67, p&lt;0.0001) was found. Patients with high TS mRNA levels (4th quartile) had significantly shorter TTP (8.7 vs 14.7 months, p=0.019) and MST (11.7 vs 24.7, p=0.018). Multivariate analysis for survival indicated that TS protein levels were an independent prognostic factor (HR=2.17; CI 1.04–4.54; p=0.038). Conclusions: TS (protein and mRNA) levels predict outcome of epithelial MPM patients treated with pemetrexed-based chemotherapy. TS quantification, if confirmed in larger prospective studies, could be used to select those patients more likely to respond to chemotherapy. [Table: see text] </jats:p

Monitoring dynamic electrochemical processes with in situ ptychography

he present work reports novel soft X-ray Fresnel CDI ptychography results, demonstrating the potential of this method for dynamic in situ studies. Specifically, in situ ptychography experiments explored the electrochemical fabrication of Co-doped Mn-oxide/polypyrrole nanocomposites for sustainable and cost-effective fuel-cell air-electrodes. Oxygen-reduction catalysts based on Mn-oxides exhibit relatively high activity, but poor durability: doping with Co has been shown to improve both reduction rate and stability