Noninvasive continuous optical monitoring of absolute cerebral blood flow in critically ill adults

We investigate a scheme for noninvasive continuous monitoring of absolute cerebral blood flow (CBF) in adult human patients based on a combination of time-resolved dynamic contrast-enhanced near-infrared spectroscopy (DCE-NIRS) and diffuse correlation spectroscopy (DCS) with semi-infinite head model of photon propogation. Continuous CBF is obtained via calibration of the DCS blood flow index (BFI) with absolute CBF obtained by intermittent intravenous injections of the optical contrast agent indocyanine green. A calibration coefficient (gamma) for the CBF is thus determined, permitting conversion of DCS BFI to absolute blood flow units at all other times. A study of patients with acute brain injury (N = 7) is carried out to ascertain the stability of gamma. The patient-averaged DCS calibration coefficient across multiple monitoring days and multiple patients was determined, and good agreement between the two calibration coefficients measured at different times during single monitoring days was found. The patient-averaged calibration coefficient of 1.24 x 10(9) (mL/100 g/min)/(cm(2)/s) was applied to previously measured DCS BFI from similar brain-injured patients||in this case, absolute CBF was underestimated compared with XeCT, an effect we show is primarily due to use of semi-infinite homogeneous models of the head.54115Agências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig

Quantification of cerebral blood flow in adults by contrast-enhanced near-infrared spectroscopy: Validation against MRI

The purpose of this study was to assess the accuracy of absolute cerebral blood flow (CBF) measurements obtained by dynamic contrast-enhanced (DCE) near-infrared spectroscopy (NIRS) using indocyanine green as a perfusion contrast agent. For validation, CBF was measured independently using the MRI perfusion method arterial spin labeling (ASL). Data were acquired at two sites and under two flow conditions (normocapnia and hypercapnia). Depth sensitivity was enhanced using time-resolved detection, which was demonstrated in a separate set of experiments using a tourniquet to temporally impede scalp blood flow. A strong correlation between CBF measurements from ASL and DCE-NIRS was observed (slope = 0.99 ± 0.08, y-intercept = −1.7 ± 7.4 mL/100 g/min, and R2 = 0.88). Mean difference between the two techniques was 1.9 mL/100 g/min (95% confidence interval ranged from −15 to 19 mL/100g/min and the mean ASL CBF was 75.4 mL/100 g/min). Error analysis showed that structural information and baseline absorption coefficient were needed for optimal CBF reconstruction with DCE-NIRS. This study demonstrated that DCE-NIRS is sensitive to blood flow in the adult brain and can provide accurate CBF measurements with the appropriate modeling techniques

SoTL Lab: Undergraduate student-faculty collaborative research in teaching and learning in CSD

The University of Wisconsin-Eau Claire Communication Sciences and Disorders SoTL Lab was designed to provide hands-on research experiences to undergraduate students on a large scale. Student reflections on experiences within the SoTL Lab identify the value of collaboration, development of confidence, and exposure to the entire research process as key outcomes. These experiences foster development of research skills and may lead students to consider academic careers

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

A PRELIMINARY STUDY ON THE TAXONOMY AND SEASONAL DISTRIBUTION OF THE ZOOPLANKTON OF THE WESTERN JOHORE STRAITS

Bachelor'sBACHELOR OF SCIENCE (HONOURS

Master's thesis recital (cello)

Suite no. 5 in C minor for cello, BWV 1011 / Johann Sebastian Bach -- Cello concerto no. 1 in C major, Hob. VIIb:1 / Joseph Haydn ; arranged for cello and pianoMusicName of supervisor unavailabl

Two essays on market behavior

textMy dissertation consists of two essays which investigate how the reaction of market participants to aggregate and firm-specific information affects asset prices and firms’ corporate choices. The first essay studies the implications of investor sentiment for asset prices. It develops a novel stock-by-stock measure of investor sentiment which I call sentiment beta. Using this measure I test several hypotheses. First hypothesis postulates that sentiment affects stocks of some firms more than others due to differences in firm characteristics. Second hypothesis predicts that more sentiment sensitive stocks are more likely to be held by individual investors. Consistent with the first hypothesis, I find that more sentiment-sensitive stocks are smaller, younger, have greater short-sales constraints, idiosyncratic volatility and lower dividend yields. Given size and volatility, high sentiment beta stocks have greater analyst coverage and institutional ownership, higher likelihood of S&P500 membership, higher turnover and lower book-to-market ratios. Stocks that are more exposed to sentiment changes deliver lower future returns, which is inconsistent with the risk factor interpretation of investor sentiment. Institutional analysis reveals that institutions stayed away from sentiment-sensitive stocks in the 1980’s, but held more of these stocks since the early 1990’s. The second essay tests a catering hypothesis which predicts that firm managers concerned about the current stock price will deviate from the optimal policy in setting profitability and revenue growth targets due to the incentives to cater to the time-varying relative investor demand for firms with different composition between revenue growth and profit margins. I develop a measure which I call a revenue growth premium and document three results consistent with catering interpretation: 1) time periods when the premium is high tend to be followed by “higher-than-expected” sales and investment growth, advertising, acquisitions and R&D; 2) catering to the premium is more pronounced among firms where managers care more about the short-term stock price; 3) consistent with “bounded rationality” version of catering story, trading strategy based on longing stocks of firms with high margin surprises and shorting firms with low margin surprises when the premium is high yields 40/bp per month after adjusting for risk and post-earnings announcement drift.Financ

Cross-Sectoral Zoonotic Disease Surveillance in Western Kenya: Identifying Drivers and Barriers Within a Resource Constrained Setting

Background: Collaboration between the human and animal health sectors, including the sharing of disease surveillance data, has the potential to improve public health outcomes through the rapid detection of zoonotic disease events prior to widespread transmission in humans. Kenya has been at the forefront of embracing a collaborative approach in Africa with the inception of the Zoonotic Disease Unit in 2011. Joint outbreak responses have been coordinated at the national level, yet little is currently documented on cross-sectoral collaboration at the sub-national level. Methods: Key informant interviews were conducted with 28 disease surveillance officers from the human and animal health sectors in three counties in western Kenya. An inductive process of thematic analysis was used to identify themes relating to barriers and drivers for cross-sectoral collaboration. Results: The study identified four interlinking themes related to drivers and barriers for cross-sectoral collaboration. To drive collaboration at the sub-national level there needs to be a clear identification of “common objectives,” as currently exemplified by the response to suspected rabies and anthrax cases and routine meat hygiene activities. The action of collaboration, be it integrated responses to outbreaks or communication and data sharing, require “operational structures” to facilitate them, including the formalisation of reporting lines, supporting legislation and the physical infrastructure, from lab equipment to mobile phones, to facilitate the activities. These structures in turn require “appropriate resources” to support them, which will be allocated based on the “political will” of those who control the resources. Conclusions: Ongoing collaborations between human and animal disease surveillance officers at the sub-national level were identified, driven by common objectives such as routine meat hygiene and response to suspected rabies and anthrax cases. In these areas a suitable operational structure is present, including a supportive legislative framework and clearly designated roles for officers within both sectors. There was support from disease surveillance officers to increase their collaboration, communication and data sharing across sectors, yet this is currently hindered by the lack of these formal operational structures and poor allocation of resources to disease surveillance. It was acknowledged that improving this resource allocation will require political will at the sub-national, national and international levels