812 research outputs found
Fingering a Murderer: A Successful Anthropological and Radiological Collaboration
We illustrate an interdisciplinary approach to identify a victim in a case with complex taphonomic and procedural issues. Burning, fragmentation, species commingling, and examination by multiple experts required anthropological preparation and analysis combined with radio- graphic adaptations to image and match trabecular patterns in unusually small, burned specimens. A missing person was last seen in the company of a reclusive female on a remote rural property. A warranted search found several burn sites containing human and animal bones. Fragment prepara- tion, analysis, and development of a biological profile by anthropologists enabled examination by the odontologist, molecular biologist, and radiolo- gist, and justified use of antemortem radiographs from one potential victim. Visual and radiological comparison resulted in a positive (later confirmed) identification of the victim by radiological matches of three carpal phalanges. Although some dimensional changes are expected with burning, morphological details were preserved, aided by selection of relatively intact, small bones for comparison
Effect of Protein Level, Lysine and Oats in Diets for Growing-Finishing Pigs
Previous research has shown that the protein content of swine diets can be reduced approximately two percent if the diet is supplemented with lysine and if the diet is not deficient in other amino acids. Corn-soybean meal diets that are reduced more than two percent in protein may become deficient in the amino acid tryptophan. Oats contains more lysine and tryptophan but less energy than corn. However, dietary levels of 20 to 30% oats have generally not affected pig performance. The objectives of this experiment were to evaluate the protein and lysine needs of growing-finishing pigs and to determine the value of oats as an amino acid source in low protein diets containing 20% oats as a replacement for corn
An analysis of MRI derived cortical complexity in premature-born adults : regional patterns, risk factors, and potential significance
Premature birth bears an increased risk for aberrant brain development concerning its structure and function. Cortical complexity (CC) expresses the fractal dimension of the brain surface and changes during neurodevelopment. We hypothesized that CC is altered after premature birth and associated with long-term cognitive development.
One-hundred-and-one very premature-born adults (gestational age <32 weeks and/or birth weight <1500 âg) and 111 term-born adults were assessed by structural MRI and cognitive testing at 26 years of age. CC was measured based on MRI by vertex-wise estimation of fractal dimension. Cognitive performance was measured based on Griffiths-Mental-Development-Scale (at 20 months) and Wechsler-Adult-Intelligence-Scales (at 26 years).
In premature-born adults, CC was decreased bilaterally in large lateral temporal and medial parietal clusters. Decreased CC was associated with lower gestational age and birth weight. Furthermore, decreased CC in the medial parietal cortices was linked with reduced full-scale IQ of premature-born adults and mediated the association between cognitive development at 20 months and IQ in adulthood.
Results demonstrate that CC is reduced in very premature-born adults in temporoparietal cortices, mediating the impact of prematurity on impaired cognitive development. These data indicate functionally relevant long-term alterations in the brainâs basic geometry of cortical organization in prematurity
Sequelae of premature birth in young adults
Background and Purpose
Qualitative studies about the abnormalities appreciated on routine magnetic resonance imaging (MRI) sequences in prematurely born adults are lacking. This article aimed at filling this knowledge gap by (1) qualitatively describing routine imaging findings in prematurely born adults, (2) evaluating measures for routine image interpretation and (3) investigating the impact of perinatal variables related to premature birth.
Methods
In this study two board-certified radiologists assessed T1-weighted and FLAIR-weighted images of 100 prematurely born adults born very preterm (VP <32 weeks) and/or at very low birth weight (VLBW <1500âŻg) and 106 controls born at full term (FT) (mean age 26.8âŻÂ±â0.7 years). The number of white matter lesions (WML) was counted according to localization. Lateral ventricle volume (LVV) was evaluated subjectively and by measurements of Evansâ index (EI) and frontal-occipital-horn ratio (FOHR). Freesurfer-based volumetry served as reference standard. Miscellaneous incidental findings were noted as free text.
Results
The LVV was increased in 24.7% of VP/VLBW individuals and significantly larger than in FT controls. This was best identified by measurement of FOHR (AUCâŻ=â0.928). Ventricular enlargement was predicted by low gestational age (odds ratio: 0.71, 95% CI 0.51â0.98) and presence of neonatal intracranial hemorrhage (odds ratio: 0.26, 95% CI 0.07â0.92). The numbers of deep and periventricular WML were increased while subcortical WMLs were not.
Conclusion
Enlargement of the LVV and deep and periventricular WMLs are typical sequelae of premature birth that can be appreciated on routine brain MRI. To increase sensitivity of abnormal LVV detection, measurement of FOHR seems feasible in clinical practice
Transcriptional analysis of temporal gene expression in germinating Clostridium difficile 630 endospores.
Clostridium difficile is the leading cause of hospital acquired diarrhoea in industrialised countries. Under conditions that are not favourable for growth, the pathogen produces metabolically dormant endospores via asymmetric cell division. These are extremely resistant to both chemical and physical stress and provide the mechanism by which C. difficile can evade the potentially fatal consequences of exposure to heat, oxygen, alcohol, and certain disinfectants. Spores are the primary infective agent and must germinate to allow for vegetative cell growth and toxin production. While spore germination in Bacillus is well understood, little is known about C. difficile germination and outgrowth. Here we use genome-wide transcriptional analysis to elucidate the temporal gene expression patterns in C. difficile 630 endospore germination. We have optimized methods for large scale production and purification of spores. The germination characteristics of purified spores have been characterized and RNA extraction protocols have been optimized. Gene expression was highly dynamic during germination and outgrowth, and was found to involve a large number of genes. Using this genome-wide, microarray approach we have identified 511 genes that are significantly up- or down-regulated during C. difficile germination (pâ€0.01). A number of functional groups of genes appeared to be co-regulated. These included transport, protein synthesis and secretion, motility and chemotaxis as well as cell wall biogenesis. These data give insight into how C. difficile re-establishes its metabolism, re-builds the basic structures of the vegetative cell and resumes growth
Unsupervised, Efficient and Semantic Expertise Retrieval
We introduce an unsupervised discriminative model for the task of retrieving
experts in online document collections. We exclusively employ textual evidence
and avoid explicit feature engineering by learning distributed word
representations in an unsupervised way. We compare our model to
state-of-the-art unsupervised statistical vector space and probabilistic
generative approaches. Our proposed log-linear model achieves the retrieval
performance levels of state-of-the-art document-centric methods with the low
inference cost of so-called profile-centric approaches. It yields a
statistically significant improved ranking over vector space and generative
models in most cases, matching the performance of supervised methods on various
benchmarks. That is, by using solely text we can do as well as methods that
work with external evidence and/or relevance feedback. A contrastive analysis
of rankings produced by discriminative and generative approaches shows that
they have complementary strengths due to the ability of the unsupervised
discriminative model to perform semantic matching.Comment: WWW2016, Proceedings of the 25th International Conference on World
Wide Web. 201
Decreased BOLD fluctuations in lateral temporal cortices of premature born adults
Lasting volume reductions in subcortical and temporal-insular cortices after premature birth suggest altered ongoing activity in these areas. We hypothesized altered fluctuations in ongoing neural excitability and activity, as measured by slowly fluctuating blood oxygenation of restingstate functional MRI (rs-fMRI), in premature born adults, with altered fluctuations being linked with underlying brain volume reductions. To investigate this hypothesis, 94 very preterm/very low birth weight (VP/VLBW) and 92 full-term born young adults underwent structural and rsfMRI data acquisition with voxel-based morphometry and amplitude of low-frequency fluctuations (ALFF) as main outcome measure. In VP/VLBW adults, ALFF was reduced in lateral temporal cortices, and this reduction was positively associated with lower birth weight. Regions of reduced ALFF overlapped with reduced brain volume. On the one hand, ALFF reduction remained after controlling for volume loss, supporting the functional nature of ALFF reductions. On the other hand, ALFF decreases were positively associated with underlying brain volume loss, indicating a relation between structural and functional changes. Furthermore, within the VP/VLBW group, reduced ALFF was associated with reduced IQ, indicating the behavioral relevance of ALFF decreases in temporal cortices. These results demonstrate long-term impact of premature birth on ongoing BOLD fluctuations in lateral temporal cortices, which are linked with brain volume reductions. Data suggest permanently reduced fluctuations in ongoing neural excitability and activity in structurally altered lateral temporal cortices after premature birth
The association of childrenâs mathematic abilities with both adultsâ cognitive abilities and intrinsic fronto-parietal networks is altered in preterm-born individuals
Mathematic abilities in childhood are highly predictive for long-term neurocognitive outcomes. Preterm-born individuals have an increased risk for both persistent cognitive impairments and long-term changes in macroscopic brain organization. We hypothesized that the association of childhood mathematic abilities with both adulthood general cognitive abilities and associated fronto-parietal intrinsic networks is altered after preterm delivery. 72 preterm- and 71 term-born individuals underwent standardized mathematic and IQ testing at 8 years and resting-state fMRI and full-scale IQ testing at 26 years of age. Outcome measure for intrinsic networks was intrinsic functional connectivity (iFC). Controlling for IQ at age eight, mathematic abilities in childhood were significantly stronger positively associated with adultsâ IQ in preterm compared with term-born individuals. In preterm-born individuals, the association of childrenâs mathematic abilities and adultsâ fronto-parietal iFC was altered. Likewise, fronto-parietal iFC was distinctively linked with preterm- and term-born adultsâ IQ. Results provide evidence that preterm birth alters the link of mathematic abilities in childhood and general cognitive abilities and fronto-parietal intrinsic networks in adulthood. Data suggest a distinct functional role of intrinsic fronto-parietal networks for preterm individuals with respect to mathematic abilities and that these networks together with associated childrenâs mathematic abilities may represent potential neurocognitive targets for early intervention
Impaired structural connectivity between dorsal attention network and pulvinar mediates the impact of premature birth on adult visualâspatial abilities
The dorsal attention network (DAN), including frontal eye fields and posterior parietal cortices, and its link with the posterior thalamus, contribute to visualâspatial abilities. Very premature birth impairs both visualâspatial abilities and corticoâthalamic structural connectivity. We hypothesized that impaired structural DANâpulvinar connectivity mediates the effect of very premature birth on adult visualâspatial abilities. Seventy very premature (median age 26.6âyears) and 57 mature born adults (median age 26.6âyears) were assessed with cognitive tests and diffusion tensor imaging. Perceptual organization (PO) index of the Wechsler Adult Intelligence ScaleâIII was used as a proxy for visualâspatial abilities, and connection probability maps in the thalamus, derived from probabilistic tractography from the DAN, were used as a proxy for DANâthalamic connectivity. Premature born adults showed decreases in both POâindex and connection probability from DAN into the pulvinar, with both changes being positively correlated. Moreover, path analysis revealed that DANâpulvinar connectivity mediates the relationship between very premature birth and POâindex. Results provide evidence for longâterm effects of very premature birth on structural DANâpulvinar connectivity, mediating the effect of prematurity on adult visualâspatial impairments. Data suggest DANâpulvinar connectivity as a specific target of prognostic and diagnostic procedures for visualâspatial abilities after premature birth
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