Changes of cerebral blood oxygenation and optical pathlength during activation and deactivation in the prefrontal cortex measured by time-resolved near infrared spectroscopy.
ABSTRACT To determine the alterations in optical characteristics and cerebral blood oxygenation (CBO) during activation and deactivation, we evaluated the changes in mean optical pathlength (MOP) and CBO induced by a verbal fluency task (VFT) and driving simulation in the right and left prefrontal cortex (PFC), employing a newly developed time-resolved near infrared spectroscopy, which allows quantitative measurements of the evoked-CBO changes by determining the MOP with a sampling time of 1 s. The results demonstrated differences in MOP in the foreheads with the subjects and wavelength; however, there was no significant difference between the right and left foreheads (p > 0.05). Also, both the VFT and driving simulation task did not affect the MOP significantly as compared to that before the tasks (p > 0.05). In the bilateral PFCs, the VFT caused increases of oxyhemoglobin and total hemoglobin associated with a decrease of deoxyhemoglobin, while the driving simulation task caused decreases of oxyhemoglobin and total hemoglobin associated with an increase of deoxyhemoglobin; there were no significant differences in evoked-CBO changes between the right and left PFC. The present results will be useful for quantitative measurement of hemodynamic changes during activation and deactivation in the adults by near infrared spectroscopy.
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ABSTRACT: Mycobacterium leprae, the causative agent of leprosy, is an unusual organism that presents unique challenges to those studying the disease through molecular epidemiology. As a consequence, many basic aspects of disease transmission and biology remain unilluminated. In this review, we explore the general principles of molecular epidemiology, and the special difficulties surrounding the application of molecular epidemiology to M. leprae. We briefly discuss the computational tools commonly employed in molecular epidemiology studies. The past decade of developments in molecular strain typing approaches through VNTRs and SNP loci, and their merits and limitations, are discussed. We summarize what has been learned about the transmission and historical origins of leprosy through molecular epidemiology and Bacterial Population Genetics, to date. Lastly, we critically evaluate the strengths and shortcomings of leprosy research, and present recommendations for future work that will hopefully shed light on some of the disease's most fundamental mysteries.Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases 06/2011; 11(7):1505-13. · 3.22 Impact Factor
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ABSTRACT: Laser Induced Breakdown Spectroscopy (LIBS) is nowadays a well established tool for qualitative, semi-quantitative and quantitative analyses of surfaces, with micro-destructive characteristics and capabilities for stratigraphy. LIBS is an appealing technique compared with many other types of elemental analysis thanks to the set up versatility facilitating non-invasive and remote analyses, as well as suitability to diagnostics in harsh environments. In this work, LIBS capabilities were used for the determination of the atomic composition of multilayered samples simulating the tiles of plasma facing components in the next generation fusion machines such as ITER. A new experimental setup was designed and realized in order to optimize the characteristics of an LIBS system working at low pressure and remotely, as it should be for an in situ system to be applied in monitoring the erosion and redeposition phenomena occurring on the inner walls of a fusion device. The effects of time delay and laser fluence on LIBS sensitivity at reduced pressure were examined, looking for operational conditions suitable to analytical applications. The quantitative analysis of some atomic species in the superficial layer has been carried out using a Calibration Free (CF) approach in the time window where Local Thermal Equilibrium (LTE) was assumed for an LIBS analysis.Chemical Physics 04/2012; · 1.96 Impact Factor
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ABSTRACT: We present a description of evolution of time-resolved systems developed at the Department of Physics, Politecnico di Milano for tissue oximetry and functional brain imaging. From a single source and 4-channel set-up we have upgraded to a potentially 18-sources and 64-channel device. An example of sensitivity of the latest set-up is reported for a motor task experiment. A short discussion on the next generation time-resolved instrumentation for functional studies is also presented.Opto-Electronics Review 16(2):131-135. · 0.92 Impact Factor