Towards quantitative acousto-optic imaging in tissue

We have investigated the possibilities and limitations of the application of ultrasound modulated coherent light to obtain quantitative information of local absorbers in light-scattering objects, among which tissue. For all objects studied, the combined use of microsecond ultrasound and light pulses enabled us to construct a 3D map of local absorbers with a spatial resolution of ∼2 mm. Moreover, in relatively homogeneous model systems, mimicking a blood vessel embedded in tissue, the use of a calibration procedure allowed for a determination of the local absorbance. Speckle decorrelation times for real tissue containing blood vessels, in which appreciable motion of scatterers can exist, were found to be smaller than 1ms. These relatively short times present a major challenge for acousto-optics to be applied in living tissue systems

Topical haemostatic agents in liver surgery: do we need them?

AbstractBackgroundWorldwide, partial liver resections are increasingly being performed for primary or secondary hepatic malignancies. There are various techniques to reduce blood loss druing liver surgery. Several topical haemostatic agents have been developed to improve haemostasis of the resection surface and these agents are used more and more, even although the true effects remain unclear.MethodsThe present literature about the use of topical haemostatic agents in liver surgery was reviewed. Furthermore we conducted a Dutch national survey to explore the use of and belief in these agents in liver surgery.ResultsThe Dutch national survey among surgeons showed that topical haemostatic agents are frequently used not only to lower intra-operative blood loss or shorten time to haemostasis, but even more importantly, to reduce resection surface related complications such as bile leakage, postoperative haemorrhage and abscess formation. Although various topical haemostatic agents have been shown to reduce intra-operative time to haemostasis at the resection surface after liver resections, there is no scientific proof that these topical haemostatic agents really reduce resection surface related complications.ConclusionThis review highlights the need for more randomized clinical trials to investigate the efficacy of topical haemostatic agents in reducing resection surface related complications

Arctic Fisheries

This background paper focuses on fisheries that occur in the Arctic marine area, including fisheries for anadromous species that spawn in rivers that flow directly into the Arctic marine area. The paper follows a sectoral perspective, but in pursuance of an ecosystem approach to fisheries (EAF). Due to this sectoral perspective, the focus will be exclusively on international instruments and intergovernmental and other relevant international bodies that relate to, or pursue, conservation as well as management. No attention will therefore be paid to those that focus exclusively on conservation of species and habitat by various means, including by the regulation of international trade

Phenotypic Selection in Ornamental Breeding: It's Better to Have the BLUPs Than to Have the BLUEs

Plant breeders always face the challenge to select the best individuals. Selection methods are required that maximize selection gain based on available data. When several crosses have been made, the BLUP procedure achieves this by combining phenotypic data with information on pedigree relationships via an index, known as family-index selection. The index, estimated based on the intra-class correlation coefficient, exploits the relationship among individuals within a family relative to other families in the population. An intra-class correlation coefficient of one indicates that the individual performance can be fully explained based on the family background, whereas an intra-class correlation coefficient of zero indicates the performance of individuals is independent of the family background. In the case the intra-class correlation coefficient is one, family-index selection is considered. In the case the intra-class correlation coefficient is zero, individual selection is considered. The main difference between individual and family-index selection lies in the adjustment in estimating the individual's effect depending on the intra-class correlation coefficient afforded by the latter. Two examples serve to illustrate the application of the BLUP method. The efficiency of individual and family-index selection was evaluated in terms of the heritability obtained from linear mixed models implementing the selection methods by suitably defining the treatment factor as the sum of individual and family effect. Family-index selection was found to be at least as efficient as individual selection in Dianthus caryophyllus L., except for flower size in standard carnation and vase life in mini carnation for which traits family-index selection outperformed individual selection. Family-index selection was superior to individual selection in Pelargonium zonale in cases when the heritability was low. Hence, the pedigree-based BLUP procedure can enhance selection efficiency in production-related traits in P. zonale or shelf-life related in D. caryophyllus L

Accurate distance control between a probe and a surface using a microcantilever

We demonstrate a method to accurately control the distance between a custom probe and a sample on a {\mu}m to nm scale. The method relies on the closed-loop feedback on the angular deflection of an in-contact AFM microcantilever. High performance in stability and accuracy is achieved in this method by taking advantage of the small mechanical feedback path between surface and probe. We describe how internal error sources that find their origin in the microcantilever and feedback can be minimized to achieve an accurate and precise control up to 3 nm. In particular, we investigated how hysteresis effects in the feedback caused by friction forces between tip and substrate, can be minimized. By applying a short calibration procedure, distance control from contact to several micrometers probe-sample distance can be obtained with an absolute nanometer-scale accuracy. The method presented is compatible with any probe that can be fixed on a microcantilever chip and can be easily built into existing AFM systems

Changes in Alcohol-Related Brain Networks Across the First Year of College: A Prospective Pilot Study Using fMRI Effective Connectivity Mapping

The upsurge in alcohol use that often occurs during the first year of college has been convincingly linked to a number of negative psychosocial consequences and may negatively affect brain development. In this longitudinal functional magnetic resonance imaging (fMRI) pilot study, we examined changes in neural responses to alcohol cues across the first year of college in a normative sample of late adolescents. Participants (N=11) were scanned three times across their first year of college (summer, first semester, second semester), while completing a go/no-go task in which images of alcoholic and non-alcoholic beverages were the response cues. A state-of-the-art effective connectivity mapping technique was used to capture spatiotemporal relations among brain regions of interest (ROIs) at the level of the group and the individual. Effective connections among ROIs implicated in cognitive control were greatest at the second assessment (when negative consequences of alcohol use increased), and effective connections among ROIs implicated in emotion processing were lower (and response times were slower) when participants were instructed to respond to alcohol cues compared to non-alcohol cues. These preliminary findings demonstrate the value of a prospective effective connectivity approach for understanding adolescent changes in alcohol-related neural processes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/123049/1/Changes in Alcohol-Related Brain Networks Across the First Year of College_A Prospective Pilot Study Using fMRI Effective Connectivity Mapping.pd

Dependence of gene-by-environment interactions (GxE) on scaling:Comparing the use of sum scores, transformed sum scores and IRT scores for the phenotype in tests of GxE interaction

Estimates of gene–environment interactions (GxE) in behavior genetic models depend on how a phenotype is scaled. Inappropriately scaled phenotypes result in biased estimates of GxE and can sometimes even suggest GxE in the direction opposite to its true direction. Previously proposed solutions are mathematically complex, computationally demanding and may prove impractical for the substantive researcher. We, therefore, evaluated two simple-to-use alternatives: (1) straightforward non-linear transformation of sum scores and (2) factor scores from an appropriate item response theory (IRT) model. Within Purcell’s (2002) GxM framework, both alternatives provided less biased parameter estimates, and improved false and true positive rates than using a raw sum score. These approaches are, therefore, recommended over using raw sum scores in tests of GxE. Circumstances under which IRT factor scores versus transformed sum scores should be preferred are discussed