B-type natriuretic peptide predicts deterioration in functional capacity following lung resection

OBJECTIVES Following lung resection, there is a decrease in the functional capacity and quality of life, which is not fully explained by changes in pulmonary function. Previous work demonstrates that B-type natriuretic peptide (BNP) is associated with short- and long-term complications following lung resection, leading to the suggestion that cardiac dysfunction may contribute to functional deterioration. Our aim was to investigate any relationship between BNP and subjective and objective indices of functional deterioration following lung resection surgery. METHODS Twenty-seven patients undergoing lung resection had serum BNP measured preoperatively, on postoperative day (POD)1 and POD2, and at 2 months postoperatively. The functional deterioration was assessed using 6-min walk tests and the Medical Research Council dyspnoea scale. ‘Deterioration in functional capacity’ was defined as either an increase in the Medical Research Council dyspnoea score or a significant decrease in the 6-min walk test distance. RESULTS BNP increased over time (P < 0.01) and was significantly elevated on POD1 and POD2 (P < 0.02 for both). Seventeen patients demonstrated functional deterioration 2 months postoperatively. At all perioperative time points, BNP was significantly higher in patients showing deterioration (P < 0.05 for all). Preoperative BNP was predictive of functional deterioration at 2 months with an area under the receiver-operating characteristic curve of 0.82 (P = 0.01, 95% confidence interval 0.65–0.99). CONCLUSIONS This study has demonstrated, using subjective and objective measures, that preoperative BNP is a predictor of functional deterioration following lung resection. BNP may have a role in preoperative risk stratification in this population, allowing therapy in future to be targeted towards high-risk patients with the aim of preventing postoperative cardiac dysfunction. Clinical trial registration number: NCT01892800

Nonlinear electrochemical impedance spectroscopy for lithium-ion battery model parameterization

In this work we analyse the local nonlinear electrochemical impedance spectroscopy (NLEIS) response of a lithium-ion battery and estimate model parameters from measured NLEIS data. The analysis assumes a single-particle model including nonlinear diffusion of lithium within the electrode particles and asymmetric charge transfer kinetics at their surface. Based on this model and assuming a moderately-small excitation amplitude, we systematically derive analytical formulae for the impedances up to the second harmonic response, allowing the meaningful interpretation of each contribution in terms of physical processes and nonlinearities in the model. The implications of this for parameterization are explored, including structural identifiability analysis and parameter estimation using maximum likelihood, with both synthetic and experimentally measured impedance data. Accurate fits to impedance data are possible, however inconsistencies in the fitted diffusion timescales suggest that a nonlinear diffusion model may not be appropriate for the cells considered. Model validation is also demonstrated by predicting time-domain voltage response using the parameterized model and this is shown to have excellent agreement with measured voltage time-series data (11.1 mV RMSE).Comment: 40 pages (excluding supplementary material). Submitted to the Journal of the Electrochemical Societ

Tritium labeling of potential lipophilic myelin probes

Two potential lipophilic myelin imaging agents (1,1,2,2‐tetrafluoro‐1,2‐diphenylethane and 1‐fluoroadamantane) were tritium labeled. The most effective method employed the microwave discharge activation of tritium gas technique and resulted in specific activities of 177 mCi/mmol for 1,1,2,2‐tetrafluoro‐1,2‐diphenylethane and 593 mCi/mmol for 1‐fluoroadamantane. Using this tritiation method significant amounts of tritium‐for‐fluorine substitution was also observed in the labeling of 1‐fluoroadamatane, resulting in nearly equivalent amounts of tritiated adamantane and fluoroadamantane.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90398/1/2580210110_ftp.pd

Comparison of GOES-Retrieved and In Situ Measurements of Deep Convective Anvil Cloud Microphysical Properties During the Tropical Composition, Cloud and Climate Coupling Experiment (TC(sup 4))

One of the main goals of the Tropical Composition, Cloud and Climate Coupling Experiment (TC(sup 4)) during July and August 2007 was to gain a better understanding of the formation and life cycle of cirrus clouds in the upper troposphere and lower stratosphere and how their presence affects the exchange of water vapor between these layers. Additionally, it is important to compare in situ measurements taken by aircraft instruments with products derived from satellite observations and find a meaningful way to interpret the results. In this study, cloud properties derived using radiance measurements from the Geostationary Operational Environmental Satellite (GOES) imagers are compared to similar quantities from aircraft in situ observations and are examined for meaningful relationships. A new method using dual \angle satellite measurements is used to derive the ice water content (IWC) for the top portion of deep convective clouds and anvils. The results show the in situ and remotely sensed mean microphysical properties agree to within approx.10 microns in the top few kilometers of thick anvils despite the vastly different temporal and spatial resolutions of the aircraft and satellite instruments. Mean particle size and IWC are shown to increase with decreasing altitude in the top few kilometers of the cloud. Given these relationships, it may be possible to derive parameterizations for effective particle size and IWC as a function of altitude from satellite observation

Non-invasive monitoring of tissue oxygenation during laparoscopic donor nephrectomy

<p>Abstract</p> <p>Background</p> <p>Standard methods for assessment of organ viability during surgery are typically limited to visual cues and tactile feedback in open surgery. However, during laparoscopic surgery, these processes are impaired. This is of particular relevance during laparoscopic renal donation, where the condition of the kidney must be optimized despite considerable manipulation. However, there is no <it>in vivo </it>methodology to monitor renal parenchymal oxygenation during laparoscopic surgery.</p> <p>Methods</p> <p>We have developed a method for the real time, <it>in vivo</it>, whole organ assessment of tissue oxygenation during laparoscopic nephrectomy to convey meaningful biological data to the surgeon during laparoscopic surgery. We apply the 3-CCD (charge coupled device) camera to monitor qualitatively renal parenchymal oxygenation with potential real-time video capability.</p> <p>Results</p> <p>We have validated this methodology in a porcine model across a range of hypoxic conditions, and have then applied the method during clinical laparoscopic donor nephrectomies during clinically relevant pneumoperitoneum. 3-CCD image enhancement produces mean region of interest (ROI) intensity values that can be directly correlated with blood oxygen saturation measurements (R²> 0.96). The calculated mean ROI intensity values obtained at the beginning of the laparoscopic nephrectomy do not differ significantly from mean ROI intensity values calculated immediately before kidney removal (<it>p </it>> 0.05).</p> <p>Conclusion</p> <p>Here, using the 3-CCD camera, we qualitatively monitor tissue oxygenation. This means of assessing intraoperative tissue oxygenation may be a useful method to avoid unintended ischemic injury during laparoscopic surgery. Preliminary results indicate that no significant changes in renal oxygenation occur as a result of pneumoperitoneum.</p

Effects of capecitabine treatment on the uptake of thymidine analogs using exploratory PET imaging agents: 18F-FAU, 18F-FMAU, and 18F-FLT

Patient Image Data. (XLSX 19 kb