Non-invasive evaluation of microvascular and endothelial function with hybrid near-infrared spectroscopies

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Hardware simulator for optical correlation spectroscopy with Gaussian statistics and arbitrary correlation functions

We present a new hardware simulator (HS) for characterization, testing and benchmarking of digital correlators used in various optical correlation spectroscopy experiments where the photon statistics is Gaussian and the corresponding time correlation function can have any arbitrary shape. Starting from the HS developed in [Rev. Sci. Instrum. 74, 4273 (2003)], and using the same I/O board (PCI-6534 National Instrument) mounted on a modern PC (Intel Core i7-CPU, 3.07GHz, 12GB RAM), we have realized an instrument capable of delivering continuous streams of TTL pulses over two channels, with a time resolution of Δt = 50ns, up to a maximum count rate of 〈I〉 ∼ 5MHz. Pulse streams, typically detected in dynamic light scattering and diffuse correlation spectroscopy experiments were generated and measured with a commercial hardware correlator obtaining measured correlation functions that match accurately the expected ones.Peer ReviewedPostprint (published version

Calibration of diffuse correlation spectroscopy with a time-resolved near-infrared technique to yield absolute cerebral blood flow measurements

A primary focus of neurointensive care is the prevention of secondary brain injury, mainly caused by ischemia. A noninvasive bedside technique for continuous monitoring of cerebral blood flow (CBF) could improve patient management by detecting ischemia before brain injury occurs. A promising technique for this purpose is diffuse correlation spectroscopy (DCS) since it can continuously monitor relative perfusion changes in deep tissue. In this study, DCS was combined with a time-resolved near-infrared technique (TR-NIR) that can directly measure CBF using indocyanine green as a flow tracer. With this combination, the TR-NIR technique can be used to convert DCS data into absolute CBF measurements. The agreement between the two techniques was assessed by concurrent measurements of CBF changes in piglets. A strong correlation between CBF changes measured by TR-NIR and changes in the scaled diffusion coefficient measured by DCS was observed (R2 = 0.93) with a slope of 1.05 ± 0.06 and an intercept of 6.4 ± 4.3% (mean ± standard error)

Preferences of Those Who Utilize Thermal Springs About Spa Tourism

Objective: Health tourism has been in the agenda recently, and our country is considerably rich in respect to thermal tourism. Therefore, the society especially tends to prefer thermal tourism. It is aimed in the study to determine the reasons why people prefer thermal tourism and which diseases they intend to cure of. Methods: The study was carried out in 2012, in two provinces famous for Turkey's thermal tourism. The sample of the study was formed the tourists who resorted these two provinces for thermal tourism in May-July. The volunteers to take part in the study were requested to fill the questionnaires prepared by the researchers by themselves. In the  questionnaires there were questions such as the socio-demographic characteristics, reasons for preferring thermal tourism, diseases for which they would benefit from spa treatment, and who they have been informed about the spa before coming to the spa. In the analysis of the data descriptive statistics and chi-square test were used and p values <0.05 were statistical considered significant. Results: The average age of 153 participants was 42.5±13.9, and 44.4 % of them declared that they had chronic diseases. 65.4% of them got information about the spa treatment before they utilized the thermal hotels. 38.6% of those who came to thermal hotels reported that they had utilized the thermal treatment before, and 18.3% of them reported that they had consulted to a medical physician before arriving there. 83.7% of ındividuals participating in the study stated that they had thought to get benefit from the thermal tourism with regard to musculoskeletal diseases. While 69.9% of the spa treatment was used as a sitting bath, 51.6% was using steam bath. 23.5% of the participants think that such treatment has side effects. Before arriving for thermal tourism, there was a statistically significant difference between application status to medical doctor with age, chronic illness.Conclusion: The individuals thought that they principally make use of thermal tourism concerning musculoskeletal system and dermatologic diseases. The level of seeking medical advice before deciding a thermal tourism was low. The way the individuals make choice of spa treatments most was sitting bath and steam bath. It is believed that increasing the level of awareness about the necessity of applying to the doctor before coming to the spa and doing extra field studies and could contribute to the support of the society's health consciousness. Keywords: Health tourism, spa tourism, thermal tourism preferenc

Looking back at fNIRS 2018

Postprint (published version

High-density speckle contrast optical tomography (SCOT) for three dimensional tomographic imaging of the small animal brain

High-density speckle contrast optical tomography (SCOT) utilizing tens of thousands of source-detector pairs, was developed for in vivo imaging of blood flow in small animals. The reduction in cerebral blood flow (CBF) due to local ischemic stroke in a mouse brain was transcanially imaged and reconstructed in three dimensions. The reconstructed volume was then compared with corresponding magnetic resonance images demonstrating that the volume of reduced CBF agrees with the infarct zone at twenty-four hours.Peer ReviewedPostprint (author's final draft

Cerebral vasoreactivity in response to a headof-bed position change is altered in patients with moderate and severe obstructive sleep apnea

Obstructive sleep apnea (OSA) can impair cerebral vasoreactivity and is associated with an increased risk of cerebrovascular disease. Unfortunately, an easy-to-use, non-invasive, portable monitor of cerebral vasoreactivity does not exist. Therefore, we have evaluated the use of near-infrared diffuse correlation spectroscopy to measure the microvascular cerebral blood flow (CBF) response to a mild head-of-bed position change as a biomarker for the evaluation of cerebral vasoreactivity alteration due to chronic OSA. Furthermore, we have monitored the effect of two years of continuous positive airway pressure (CPAP) treatment on the cerebral vasoreactivity.Peer ReviewedPostprint (published version

Monitoring of pregnant and infants in Konya district before and after transformation in health-care system

Objectives: The study was aimed to assess whethermonitoring of pregnant women and infants were appropriateaccording to the protocols in the field.Materials and methods: This cross-sectional study wasperformed in Konya city center. In 2006, sample size wascalculated for pre-natal care in urban population (n=175).Same sample size was used as a base for infants. Theneighborhoods from which the clusters were to be takenwere selected randomly. Same sample size and progresswere also used in 2011. Data were collected by face-tofaceinterview with the pregnant and mothers.Results: The average week of pregnancy was 25±9. Thepercentage of unmonitored pregnant was 23% in 2006and 7% in 2011 (P<0.001). The median of monitoringwere 2 and 3 in 2006 and 2011 respectively (P<0.001).The percentage of pregnant monitoring in accordancewith monitoring protocol of Ministry of Health in terms ofcorrect timing and proper numbers was 51% in 2006 and79% in 2011 (P<0.001). Total antenatal care increasedfrom 91% to 99% in five years (P<0.01). The mean ageof infants involved into the study was 6±3 months. Thepercentage of unmonitored infants was 6% in 2006 and2% in 2011 (P<0.01). The median of monitoring was 3 in2006 and 4 in 2011 (P<0.01). The percentage of monitoringproper to the time intervals stated in protocols decreasedfrom 33% to 18% (P<0.01).Conclusion: While most parameters of pregnant andinfant monitoring increased in urban population, the percentageof in-time monitoring decreased