Specimen specific parameter identification of ovine lumbar intervertebral discs: On the influence of fibre-matrix and fibre-fibre shear interactions.

Numerical models of the intervertebral disc, which address mechanical questions commonly make use of the difference in water content between annulus and nucleus, and thus fluid and solid parts are separated. Despite this simplification, models remain complex due to the anisotropy and nonlinearity of the annulus and regional variations of the collagen fibre density. Additionally, it has been shown that cross-links make a large contribution to the stiffness of the annulus. Because of this complex composite structure, it is difficult to reproduce several sets of experimental data with one single set of material parameters. This study addresses the question to which extent the ultrastructure of the intervertebral disc should be modelled so that its moment-angle behaviour can be adequately described. Therefore, a hyperelastic constitutive law, based on continuum mechanical principles was derived, which does not only consider the anisotropy from the collagen fibres, but also interactions among the fibres and between the fibres and the ground substance. Eight ovine lumbar intervertebral discs were tested on a custom made spinal loading simulator in flexion/extension, lateral bending and axial rotation. Specimen-specific geometrical models were generated using CT images and T2 maps to distinguish between annulus fibrosus and nucleus pulposus. For the identification of the material parameters the annulus fibrosus was described with two scenarios: with and without fibre-matrix and fibre-fibre interactions. Both scenarios showed a similar behaviour on a load displacement level. Comparing model predictions to the experimental data, the mean RMS of all specimens and all load cases was 0.54±0.15° without the interaction and 0.54±0.19° when the fibre-matrix and fibre-fibre interactions were included. However, due to the increased stiffness when cross-links effects were included, this scenario showed more physiological stress-strain relations in uniaxial and biaxial stress states. Thus, the present study suggests that fibre-matrix and fibre-fibre interactions should be considered in the constitutive law when the model addresses questions concerning the stress field of the annulus fibrosus.

Associative processing and paranormal belief

In the present study we introduce a novel task for the quantitative assessment of both originality and speed of individual associations. This 'BAG' (Bridge-the-Associative-Gap) task was used to investigate the relationships between creativity and paranormal belief. Twelve strong 'believers' and 12 strong 'skeptics' in paranormal phenomena were selected from a large student population (n > 350). Subjects were asked to produce single-word associations to word pairs. In 40 trials the two stimulus words were semantically indirectly related and in 40 other trials the words were semantically unrelated. Separately for these two stimulus types, response commonalities and association latencies were calculated. The main finding was that for unrelated stimuli, believers produced associations that were more original (had a lower frequency of occurrence in the group as a whole) than those of the skeptics. For the interpretation of the result we propose a model of association behavior that captures both 'positive' psychological aspects (i.e., verbal creativity) and 'negative' aspects (susceptibility to unfounded inferences), and outline its relevance for psychiatry. This model suggests that believers adopt a looser response criterion than skeptics when confronted with 'semantic noise'. Such a signal detection view of the presence/absence of judgments for loose semantic relations may help to elucidate the commonalities between creative thinking, paranormal belief and delusional ideation.

XMapTools: a MATLAB©-based program for electron microprobe X-ray image processing and geothermobarometry

XMapTools is a MATLAB©-based graphical user interface program for electron microprobe X-ray image processing, which can be used to estimate the pressure–temperature conditions of crystallization of minerals in metamorphic rocks. This program (available online at http://www.xmaptools.com) provides a method to standardize raw electron microprobe data and includes functions to calculate the oxide weight percent compositions for various minerals. A set of external functions is provided to calculate structural formulae from the standardized analyses as well as to estimate pressure–temperature conditions of crystallization, using empirical and semi-empirical thermobarometers from the literature. Two graphical user interface modules, Chem2D and Triplot3D, are used to plot mineral compositions into binary and ternary diagrams. As an example, the software is used to study a high-pressure Himalayan eclogite sample from the Stak massif in Pakistan. The high-pressure paragenesis consisting of omphacite and garnet has been retrogressed to a symplectitic assemblage of amphibole, plagioclase and clinopyroxene. Mineral compositions corresponding to ~165,000 analyses yield estimates for the eclogitic pressure–temperature retrograde path from 25 kbar to 9 kbar. Corresponding pressure–temperature maps were plotted and used to interpret the link between the equilibrium conditions of crystallization and the symplectitic microstructures. This example illustrates the usefulness of XMapTools for studying variations of the chemical composition of minerals and for retrieving information on metamorphic conditions on a microscale, towards computation of continuous pressure–temperature-and relative time path in zoned metamorphic minerals not affected by post-crystallization diffusion.

Statistical Learning, Syllable Processing, and Speech Production in Healthy Hearing and Hearing-Impaired Preschool Children: A Mismatch Negativity Study

OBJECTIVES The objectives of the present study were to investigate temporal/spectral sound-feature processing in preschool children (4 to 7 years old) with peripheral hearing loss compared with age-matched controls. The results verified the presence of statistical learning, which was diminished in children with hearing impairments (HIs), and elucidated possible perceptual mediators of speech production. DESIGN Perception and production of the syllables /ba/, /da/, /ta/, and /na/ were recorded in 13 children with normal hearing and 13 children with HI. Perception was assessed physiologically through event-related potentials (ERPs) recorded by EEG in a multifeature mismatch negativity paradigm and behaviorally through a discrimination task. Temporal and spectral features of the ERPs during speech perception were analyzed, and speech production was quantitatively evaluated using speech motor maximum performance tasks. RESULTS Proximal to stimulus onset, children with HI displayed a difference in map topography, indicating diminished statistical learning. In later ERP components, children with HI exhibited reduced amplitudes in the N2 and early parts of the late disciminative negativity components specifically, which are associated with temporal and spectral control mechanisms. Abnormalities of speech perception were only subtly reflected in speech production, as the lone difference found in speech production studies was a mild delay in regulating speech intensity. CONCLUSIONS In addition to previously reported deficits of sound-feature discriminations, the present study results reflect diminished statistical learning in children with HI, which plays an early and important, but so far neglected, role in phonological processing. Furthermore, the lack of corresponding behavioral abnormalities in speech production implies that impaired perceptual capacities do not necessarily translate into productive deficits.

Linking altered central pain processing and genetic polymorphism to drug efficacy in chronic low back pain.

BACKGROUND Inability to predict the therapeutic effect of a drug in individual pain patients prolongs the process of drug and dose finding until satisfactory pharmacotherapy can be achieved. Many chronic pain conditions are associated with hypersensitivity of the nervous system or impaired endogenous pain modulation. Pharmacotherapy often aims at influencing these disturbed nociceptive processes. Its effect might therefore depend on the extent to which they are altered. Quantitative sensory testing (QST) can evaluate various aspects of pain processing and might therefore be able to predict the analgesic efficacy of a given drug. In the present study three drugs commonly used in the pharmacological management of chronic low back pain are investigated. The primary objective is to examine the ability of QST to predict pain reduction. As a secondary objective, the analgesic effects of these drugs and their effect on QST are evaluated. METHODS/DESIGN In this randomized, double blinded, placebo controlled cross-over study, patients with chronic low back pain are randomly assigned to imipramine, oxycodone or clobazam versus active placebo. QST is assessed at baseline, 1 and 2 h after drug administration. Pain intensity, side effects and patients' global impression of change are assessed in intervals of 30 min up to two hours after drug intake. Baseline QST is used as explanatory variable to predict drug effect. The change in QST over time is analyzed to describe the pharmacodynamic effects of each drug on experimental pain modalities. Genetic polymorphisms are analyzed as co-variables. DISCUSSION Pharmacotherapy is a mainstay in chronic pain treatment. Antidepressants, anticonvulsants and opioids are frequently prescribed in a "trial and error" fashion, without knowledge however, which drug suits best which patient. The present study addresses the important need to translate recent advances in pain research to clinical practice. Assessing the predictive value of central hypersensitivity and endogenous pain modulation could allow for the implementation of a mechanism-based treatment strategy in individual patients. TRIAL REGISTRATION Clinicaltrials.gov, NCT01179828.

Prestimulus default mode activity influences depth of processing and recognition in an emotional memory task

Low self-referential thoughts are associated with better concentration, which leads to deeper encoding and increases learning and subsequent retrieval. There is evidence that being engaged in externally rather than internally focused tasks is related to low neural activity in the default mode network (DMN) promoting open mind and the deep elaboration of new information. Thus, reduced DMN activity should lead to enhanced concentration, comprehensive stimulus evaluation including emotional categorization, deeper stimulus processing, and better long-term retention over one whole week. In this fMRI study, we investigated brain activation preceding and during incidental encoding of emotional pictures and on subsequent recognition performance. During fMRI, 24 subjects were exposed to 80 pictures of different emotional valence and subsequently asked to complete an online recognition task one week later. Results indicate that neural activity within the medial temporal lobes during encoding predicts subsequent memory performance. Moreover, a low activity of the default mode network preceding incidental encoding leads to slightly better recognition performance independent of the emotional perception of a picture. The findings indicate that the suppression of internally-oriented thoughts leads to a more comprehensive and thorough evaluation of a stimulus and its emotional valence. Reduced activation of the DMN prior to stimulus onset is associated with deeper encoding and enhanced consolidation and retrieval performance even one week later. Even small prestimulus lapses of attention influence consolidation and subsequent recognition performance. Hum Brain Mapp, 2015. © 2015 Wiley Periodicals, Inc.

Cycling in the nucleus: regulation of RNA 3' processing and nuclear organization of replication-dependent histone genes.

The histones which pack new DNA during the S phase of animal cells are made from mRNAs that are cleaved at their 3' end but not polyadenylated. Some of the factors used in this reaction are unique to it while others are shared with the polyadenylation process that generates all other mRNAs. Recent work has begun to shed light on how the cell manages the assignment of these common components to the two 3' processing systems, and how it achieves their cell cycle-regulation and recruitment to the histone pre-mRNA. Moreover, recent and older findings reveal multiple connections between the nuclear organization of histone genes, their transcription and 3' end processing as well as the control of cell proliferation.

Special Tax Treatment as Trade Policy: A Database on Export Processing and Special Economic Zones

Many countries treat income generated via exports favourably, especially when production takes places in special zones known as export processing zones (EPZs). EPZs can be defined as specific, geographically defined zones or areas that are subject to special administration and that generally offer tax incentives, such as duty‐free imports when producing for export, exemption from other regulatory constraints linked to import for the domestic market, sometimes favourable treatment in terms of industrial regulation, and the streamlining of border clearing procedures. We describe a database of WTO Members that employ special economic zones as part of their industrial policy mix. This is based on WTO notification and monitoring through the WTO’s trade policy review mechanism (TPRM), supplemented with information from the ILO, World Bank, and primary sources. We also provide some rough analysis of the relationship between use of EPZs and the carbon intensity of exports, and relative levels of investment across countries with and without special zones.

Output processing and automatic reporting with Stata

This talk illustrates how results from various Stata commands can be processed efficiently for inclusion in customized reports. A two-step procedure is proposed in which results are gathered and archived in the first step and then tabulated in the second step. Such an approach disentangles the tasks of computing results (which may take long) and preparing results for inclusion in presentations, papers, and reports (which you may have to do over and over). Examples using results from model estimation commands and various other Stata commands such as tabulate, summarize, or correlate are presented. Users will also be shown how to dynamically link results into word processors or into LaTeX documents.

Relationship between fibre orientation and tensile strength of natural collagen membranes for heart valve leaflets

Heart valve prostheses are used to replace native heart valves which that are damaged because of congenital diseases or due to ageing. Biological prostheses made of bovine pericardium are similar to native valves and do not require any anticoagulation treatment, but are less durable than mechanical prostheses and usually fail by tearing. Researches are oriented in improving the resistance and durability of biological heart valve prostheses in order to increase their life expectancy. To understand the mechanical behaviour of bovine pericardium and relate it to its microstructure (mainly collagen fibres concentration and orientation) uniaxial tensile tests have been performed on a model material made of collagen fibres. Small Angle Light Scattering (SALS) has been also used to characterize the microstructure without damaging the material. Results with the model material allowed us to obtain the orientation of the fibres, relating the microstructure to mechanical performance

Processing and adsorption control in ZnO single nanowire photodetectors

ZnO single nanowire photodetectors have been measured in different ambient conditions in order to understand and control adsorption processes on the surface. A decrease in the conductivity has been observed as a function of time when the nanowires are exposed to air, due to adsorbed O2/H2O species at the nanowire surface. In order to have a device with stable characteristics in time, thermal desorption has been used to recover the original conductivity followed by PMMA coating of the exposed nanowire surface.

Processing and validation of JEFF3-3.1.2 Cross-section Library into Various Formats: ACE, PENDF, GENDF, MATXSR and BOXER.

Following the processing and validation of JEFF-3.1 performed in 2006 and presented in ND2007, and as a consequence of the latest updated of this library (JEFF-3.1.2) in February 2012, a new processing and validation of JEFF-3.1.2 cross section library is presented in this paper. The processed library in ACE format at ten different temperatures was generated with NJOY-99.364 nuclear data processing system. In addition, NJOY-99 inputs are provided to generate PENDF, GENDF, MATXSR and BOXER formats. The library has undergone strict QA procedures, being compared with other available libraries (e.g. ENDF/B-VII.1) and processing codes as PREPRO-2000 codes. A set of 119 criticality benchmark experiments taken from ICSBEP-2010 has been used for validation purposes.

Evolution of microstructure, macrotexture and mechanical properties of commercially pure Ti during ECAP-conform processing and drawing

Long-length ultrafine-grained (UFG) Ti rods are produced by equal-channel angular pressing via the conform scheme (ECAP-C) at 200 °C, which is followed by drawing at 200 °C. The evolution of microstructure, macrotexture, and mechanical properties (yield strength, ultimate tensile strength, failure stress, uniform elongation, elongation to failure) of pure Ti during this thermo-mechanical processing is studied. Special attention is also paid to the effect of microstructure on the mechanical behavior of the material after macrolocalization of plastic flow. The number of ECAP-C passes varies in the range of 1–10. The microstructure is more refined with increasing number of ECAP-C passes. Formation of homogeneous microstructure with a grain/subgrain size of 200 nm and its saturation after 6 ECAP-C passes are observed. Strength properties increase with increasing number of ECAP passes and saturate after 6 ECAP-C passes to a yield strength of 973 MPa, an ultimate tensile strength of 1035 MPa, and a true failure stress of 1400 MPa (from 625, 750, and 1150 MPa in the as-received condition). The true strain at failure failure decreases after ECAP-C processing. The reduction of area and true strain to failure values do not decrease after ECAP-C processing. The sample after 6 ECAP-C passes is subjected to drawing at 200¯C resulting in reduction of a grain/subgrain size to 150 nm, formation of (10 1¯0) fiber texture with respect to the rod axis, and further increase of the yield strength up to 1190 MPa, the ultimate tensile strength up to 1230 MPa and the true failure stress up to 1600 MPa. It is demonstrated that UFG CP Ti has low resistance to macrolocalization of plastic deformation and high resistance to crack formation after necking.

Effects of Dietary Fibre (Pectin) and/or Increased Protein (Casein or Pea) on Satiety, Body Weight, Adiposity and Caecal Fermentation in High Fat Diet-Induced Obese Rats

Funding: This work was funded by the Scottish Government Rural and Environment Science and Analytical Services Division. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.