Normal approximation of subgraph counts in the random-connection model

This paper derives normal approximation results for subgraph counts written as multiparameter stochastic integrals in a random-connection model based on a Poisson point process. By combinatorial arguments we express the cumulants of general subgraph counts using sums over connected partition diagrams, after cancellation of terms obtained by M\"obius inversion. Using the Statulevi\v{c}ius condition, we deduce convergence rates in the Kolmogorov distance by studying the growth of subgraph count cumulants as the intensity of the underlying Poisson point process tends to infinity. Our analysis covers general subgraphs in the dilute and full random graph regimes, and tree-like subgraphs in the sparse random graph regime

Estimation of Grain Orientation in an Anisotropic Weld by Using a Model of Ultrasonic Propagation in an Inverse Scheme

The initial step towards a nondestructive technique that estimates grain orientation in an anisotropic weld is presented in this paper. The purpose is to aid future forward simulations of ultrasonic NDT of this kind of weld to achieve a better result. A forward model that consists of a weld model, a transmitter model, a receiver model, and a 2D ray tracing algorithm is introduced. An inversion based on a multiobjective genetic algorithm is also presented. Experiments are conducted for both P and SV waves in order to collect enough data used in the inversion. Calculation is conducted to fulfill the estimation with both the synthetic data and the experimental data. Concluding remarks are presented at the end of the paper

Local brain temperature manipulation system and physiological parameters (R2', CBF and ADC) measurements in acute stroke

Accurate prediction of final lesion is critically important for clinical decision making in the management of acute ischemia stroke patients. In addition to the widely utilized perfusion and diffusion parameters, an MR derived cerebral oxygen metabolism index, which includes both cerebral blood flow (CBF) and oxygen consumption measurements using R2' (OMI_ R2'), may be a potential candidate for infarction prediction. In this study, we sought to evaluate how these MR parameters may delineate infarction in rats with ischemic injury. There is overwhelming evidence from animal studies showing that cooling may improve outcome after cerebral ischemia, while hyperthermia exacerbates neurological injury. However, how physiology parameters during ischemic injury are modulated by brain temperature is largely unknown. In this study, we first designed an MR compatible focal brain temperature manipulation system, which can regulate brain temperature, while keeping body temperature and other physiology parameters within the normal range. The relationship between T1 and temperature in brain tissue was investigated, which can be used to derive the brain temperature for the studies under hypothermic conditions. The relationship between CBF and temperature was also studied under ischemic condition. Our results showed that this device can manipulate brain temperature from 39 to the target temperature of 29 within 10 minutes and maintain it for a long period of time. Furthermore, the device allows flexible manipulation of brain temperature. A highly linear relationship between the change of T1 and change of temperature was observed. Highly linear relationships between CBF and temperature in regions with different severity of ischemic conditions were found, with the highest slope in the normal region, whiles the lowest slope in the infarct region. The possible explanation for this finding may be the breakdown of auto regulation of cerebral hemodynamic in ischemic regions. The GESSE sequence was utilized for the measurement of R2'. Multiple navigator echoes were used for motion correction. In addition, the z-shimming method was applied for B0 inhomogeneity correction. Highly consistent R2' measurements were obtained in normal rats, with a standard deviation less than 1.4Hz and 2.1Hz in subcortical and cortical areas, respectively. With 45 minutes of MCAO, the relationship between ADC, CBF, R2' and OMI_R2' right before reperfusion was studied. Elevated R2' in both the lesion and peri-lesion regions were observed. The elevated R2' in the peri-lesion region leads to a comparable OMI_R2' as that of the contralateral hemisphere, suggesting that tissue may remain viable. However, a similar behavior was also observed in the core area which will require additional investigation

Construction and characterization of an infectious clone of coxsackievirus A16

<p>Abstract</p> <p>Background</p> <p>Coxsackievirus A16 (CVA16) is a member of the <it>Enterovirus </it>genus of the <it>Picornaviridae </it>family and it is a major etiological agent of hand, foot, and mouth disease (HFMD), which is a common illness affecting children. CVA16 possesses a single-stranded positive-sense RNA genome containing approximately 7410 bases. Current understanding of the replication, structure and virulence determinants of CVA16 is very limited, partly due to difficulties in directly manipulating its RNA genome.</p> <p>Results</p> <p>Two overlapping cDNA fragments were amplified by RT-PCR from the genome of the shzh05-1 strain of CVA16, encompassing the nucleotide regions 1-4392 and 4381-7410, respectively. These two fragments were then joined <it>via </it>a native <it>Xba</it>I site to yield a full-length cDNA. A T7 promoter and poly(A) tail were added to the 5' and 3' ends, respectively, forming a full CVA16 cDNA clone. Transfection of RD cells <it>in vitro </it>with RNA transcribed directly from the cDNA clone allowed the recovery of infectious virus in culture. The CVA16 virus recovered from these cultures was functionally and genetically identical to its parent strain.</p> <p>Conclusions</p> <p>We report the first construction and characterization of an infectious cDNA clone of CVA16. The availability of this infectious clone will greatly enhance future virological investigations and vaccine development for CVA16.</p

WGCN: Graph Convolutional Networks with Weighted Structural Features

Graph structural information such as topologies or connectivities provides valuable guidance for graph convolutional networks (GCNs) to learn nodes' representations. Existing GCN models that capture nodes' structural information weight in- and out-neighbors equally or differentiate in- and out-neighbors globally without considering nodes' local topologies. We observe that in- and out-neighbors contribute differently for nodes with different local topologies. To explore the directional structural information for different nodes, we propose a GCN model with weighted structural features, named WGCN. WGCN first captures nodes' structural fingerprints via a direction and degree aware Random Walk with Restart algorithm, where the walk is guided by both edge direction and nodes' in- and out-degrees. Then, the interactions between nodes' structural fingerprints are used as the weighted node structural features. To further capture nodes' high-order dependencies and graph geometry, WGCN embeds graphs into a latent space to obtain nodes' latent neighbors and geometrical relationships. Based on nodes' geometrical relationships in the latent space, WGCN differentiates latent, in-, and out-neighbors with an attention-based geometrical aggregation. Experiments on transductive node classification tasks show that WGCN outperforms the baseline models consistently by up to 17.07% in terms of accuracy on five benchmark datasets

Absolute Oxygenation Metabolism Measurements Using Magnetic Resonance Imaging

Cerebral oxygen metabolism plays a critical role in maintaining normal function of the brain. It is the primary energy source to sustain neuronal functions. Abnormalities in oxygen metabolism occur in various neuro-pathologic conditions such as ischemic stroke, cerebral trauma, cancer, Alzheimer’s disease and shock. Therefore, the ability to quantitatively measure tissue oxygenation and oxygen metabolism is essential to the understanding of pathophysiology and treatment of various diseases. The focus of this review is to provide an introduction of various blood oxygenation level dependent (BOLD) contrast methods for absolute measurements of tissue oxygenation, including both magnitude and phase image based approaches. The advantages and disadvantages of each method are discussed