Ultrasonic Characterization of Porosity in Composite Materials by Time Delay Spectrometry

The presence of porosity in a wide range of materials, whether ceramics, steel or fiber reinforced composites, has a dramatic effect on the strength and mechanical properties of that material. Therefore, the presence of any porosity in a composite laminate during the manufacture of aerospace components is a basis for component rejection

Hirsch Index and Truth Survival in Clinical Research

BACKGROUND: Factors associated with the survival of truth of clinical conclusions in the medical literature are unknown. We hypothesized that publications with a first author having a higher Hirsch' index value (h-I), which quantifies and predicts an individual's scientific research output, should have a longer half-life. METHODS AND RESULTS: 474 original articles concerning cirrhosis or hepatitis published from 1945 to 1999 were selected. The survivals of the main conclusions were updated in 2009. The truth survival was assessed by time-dependent methods (Kaplan Meier method and Cox). A conclusion was considered to be true, obsolete or false when three or more observers out of the six stated it to be so. 284 out of 474 conclusions (60%) were still considered true, 90 (19%) were considered obsolete and 100 (21%) false. The median of the h-I was=24 (range 1-85). Authors with true conclusions had significantly higher h-I (median=28) than those with obsolete (h-I=19; P=0.002) or false conclusions (h-I=19; P=0.01). The factors associated (P<0.0001) with h-I were: scientific life (h-I=33 for>30 years vs. 16 for<30 years), -methodological quality score (h-I=36 for high vs. 20 for low scores), and -positive predictive value combining power, ratio of true to not-true relationships and bias (h-I=33 for high vs. 20 for low values). In multivariate analysis, the risk ratio of h-I was 1.003 (95%CI, 0.994-1.011), and was not significant (P=0.56). In a subgroup restricted to 111 articles with a negative conclusion, we observed a significant independent prognostic value of h-I (risk ratio=1.033; 95%CI, 1.008-1.059; P=0.009). Using an extrapolation of h-I at the time of article publication there was a significant and independent prognostic value of baseline h-I (risk ratio=0.027; P=0.0001). CONCLUSIONS: The present study failed to clearly demonstrate that the h-index of authors was a prognostic factor for truth survival. However the h-index was associated with true conclusions, methodological quality of trials and positive predictive values

Future developments in brain-machine interface research

Neuroprosthetic devices based on brain-machine interface technology hold promise for the restoration of body mobility in patients suffering from devastating motor deficits caused by brain injury, neurologic diseases and limb loss. During the last decade, considerable progress has been achieved in this multidisciplinary research, mainly in the brain-machine interface that enacts upper-limb functionality. However, a considerable number of problems need to be resolved before fully functional limb neuroprostheses can be built. To move towards developing neuroprosthetic devices for humans, brain-machine interface research has to address a number of issues related to improving the quality of neuronal recordings, achieving stable, long-term performance, and extending the brain-machine interface approach to a broad range of motor and sensory functions. Here, we review the future steps that are part of the strategic plan of the Duke University Center for Neuroengineering, and its partners, the Brazilian National Institute of Brain-Machine Interfaces and the École Polytechnique Fédérale de Lausanne (EPFL) Center for Neuroprosthetics, to bring this new technology to clinical fruition

Plasmatic and urinary glycosaminoglycans characterization in mucopolysaccharidosis II Patient treated with enzyme-replacement therapy with Idursulfase

We report the structural characterization of plasmatic and urinary GAGs in a Patient affected by MPS II (Hunter syndrome) before and during the first ten months of enzyme-replacement therapy (ERT). Plasmatic GAGs before ERT were rich in pathological DS consisting of iduronic acid (IdoA) and composed of ~90% \uf044Di4s and trace amounts of disulfated disaccharides. DS was also characterized as the main (~90%) urinary GAG mainly composed of ~90% \uf044Di4s with minor percentages of monosulfated and disulfated disaccharides, in particular \u394Di2,4dis. After 300 days of ERT, plasmatic DS strongly decreased but ~14% of IdoA-rich \uf044Di4s was still detected. Similarly, urinary galactosaminoglycans were mainly composed of 78% \uf044Di4s, ~11% \uf044Di6s and ~4% \uf044Di0s with the persistence of \u394Di2,4dis (~4%). About 40% of IdoA-formed \uf044Di4s were also calculated thus confirming that pathological DS is still present in excreted urinary GAGs during ERT. By considering the % of IdoA, we observed rather similar kinetics of excretion in fluids from the beginning of the treatment. Immediately after the first enzyme infusion, a large amount of abnormal DS is removed from tissues reaching the blood compartment and eliminated via the urine, and this process lasts for about two weeks. After this, the percentage of IdoA-rich material present in biological fluids remains fairly constant over the following nine months of treatment. To date, these are the first data regarding plasmatic and urinary kinetics directly measured on products released by the activity of the recombinant enzyme Idursulfase, iduronate-2-sulfatase, evaluated using specific and sensitive analytical procedures

Massive stars as thermonuclear reactors and their explosions following core collapse

Nuclear reactions transform atomic nuclei inside stars. This is the process of stellar nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars are reviewed. How stars manage to burn their fuel so slowly most of the time are also considered. Stellar thermonuclear reactions involving protons in hydrostatic burning are discussed first. Then I discuss triple alpha reactions in the helium burning stage. Carbon and oxygen survive in red giant stars because of the nuclear structure of oxygen and neon. Further nuclear burning of carbon, neon, oxygen and silicon in quiescent conditions are discussed next. In the subsequent core-collapse phase, neutronization due to electron capture from the top of the Fermi sea in a degenerate core takes place. The expected signal of neutrinos from a nearby supernova is calculated. The supernova often explodes inside a dense circumstellar medium, which is established due to the progenitor star losing its outermost envelope in a stellar wind or mass transfer in a binary system. The nature of the circumstellar medium and the ejecta of the supernova and their dynamics are revealed by observations in the optical, IR, radio, and X-ray bands, and I discuss some of these observations and their interpretations.Comment: To be published in " Principles and Perspectives in Cosmochemistry" Lecture Notes on Kodai School on Synthesis of Elements in Stars; ed. by Aruna Goswami & Eswar Reddy, Springer Verlag, 2009. Contains 21 figure

Living on the edge: utilising lidar data to assess the importance of vegetation structure for avian diversity in fragmented woodlands and their edges

Context: In agricultural landscapes, small woodland patches can be important wildlife refuges. Their value in maintaining biodiversity may, however, be compromised by isolation, and so knowledge about the role of habitat structure is vital to understand the drivers of diversity. This study examined how avian diversity and abundance were related to habitat structure in four small woods in an agricultural landscape in eastern England. Objectives: The aims were to examine the edge effect on bird diversity and abundance, and the contributory role of vegetation structure. Specifically: what is the role of vegetation structure on edge effects, and which edge structures support the greatest bird diversity? Methods: Annual breeding bird census data for 28 species were combined with airborne lidar data in linear mixed models fitted separately at (i) the whole wood level, and (ii) for the woodland edges only. Results: Despite relatively small woodland areas (4.9–9.4 ha), bird diversity increased significantly towards the edges, being driven in part by vegetation structure. At the whole woods level, diversity was positively associated with increased vegetation above 0.5 m and especially with increasing vegetation density in the understorey layer, which was more abundant at the woodland edges. Diversity along the edges was largely driven by the density of vegetation below 4 m. Conclusions: The results demonstrate that bird diversity was maximised by a diverse vegetation structure across the wood and especially a dense understorey along the edge. These findings can assist bird conservation by guiding habitat management of remaining woodland patches

Neurobehavioral consequences of chronic intrauterine opioid exposure in infants and preschool children: a systematic review and meta-analysis

&lt;b&gt;Background&lt;/b&gt;&lt;p&gt;&lt;/p&gt; It is assumed within the accumulated literature that children born of pregnant opioid dependent mothers have impaired neurobehavioral function as a consequence of chronic intrauterine opioid use.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Quantitative and systematic review of the literature on the consequences of chronic maternal opioid use during pregnancy on neurobehavioral function of children was conducted using the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We searched Cinahl, EMBASE, PsychINFO and MEDLINE between the periods of January 1995 to January 2012.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt;&lt;p&gt;&lt;/p&gt; There were only 5 studies out of the 200 identified that quantitatively reported on neurobehavioral function of children after maternal opioid use during pregnancy. All 5 were case control studies with the number of exposed subjects within the studies ranging from 33–143 and 45–85 for the controls. This meta-analysis showed no significant impairments, at a non-conservative significance level of p &#60; 0.05, for cognitive, psychomotor or observed behavioural outcomes for chronic intra-uterine exposed infants and pre-school children compared to non-exposed infants and children. However, all domains suggested a trend to poor outcomes in infants/children of opioid using mothers. The magnitude of all possible effects was small according to Cohen’s benchmark criteria.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Chronic intra-uterine opioid exposed infants and pre-school children experienced no significant impairment in neurobehavioral outcomes when compared to non-exposed peers, although in all domains there was a trend to poorer outcomes. The findings of this review are limited by the small number of studies analysed, the heterogenous populations and small numbers within the individual studies. Longitudinal studies are needed to determine if any neuropsychological impairments appear after the age of 5 years and to help investigate further the role of environmental risk factors on the effect of ‘core’ phenotypes

Microdevices for extensional rheometry of low viscosity elastic liquids : a review

Extensional flows and the underlying stability/instability mechanisms are of extreme relevance to the efficient operation of inkjet printing, coating processes and drug delivery systems, as well as for the generation of micro droplets. The development of an extensional rheometer to characterize the extensional properties of low viscosity fluids has therefore stimulated great interest of researchers, particularly in the last decade. Microfluidics has proven to be an extraordinary working platform and different configurations of potential extensional microrheometers have been proposed. In this review, we present an overview of several successful designs, together with a critical assessment of their capabilities and limitations