2.45GHz radiofrequency fields alter gene expression in cultured human cells

AbstractThe biological effect of radiofrequency (RF) fields remains controversial. We address this issue by examining whether RF fields can cause changes in gene expression. We used the pulsed RF fields at a frequency of 2.45GHz that is commonly used in telecommunication to expose cultured human HL-60 cells. We used the serial analysis of gene expression (SAGE) method to measure the RF effect on gene expression at the genome level. We observed that 221 genes altered their expression after a 2-h exposure. The number of affected genes increased to 759 after a 6-h exposure. Functional classification of the affected genes reveals that apoptosis-related genes were among the upregulated ones and the cell cycle genes among the downregulated ones. We observed no significant increase in the expression of heat shock genes. These results indicate that the RF fields at 2.45GHz can alter gene expression in cultured human cells through non-thermal mechanism

New psittacosaurid highlights skull enlargement in horned dinosaurs

A new psittacosaurid is based on a nearly complete articulated skeleton from northeastern China that differs principally in skull size as compared to the most common and widespread species, Psittacosaurus mongoliensis. The skull of Psittacosaurus majorsp. nov., is 25% larger despite very similar postcranial skeletal dimensions. Such selective skull enlargement is very unusual. Skull size in ceratopsians, in general, scales with positive allometry relative to body mass: species of greater mass have proportionately larger skulls. This pattern stands in marked contrast to that for other vertebrate herbivores, in which larger−bodied species either have proportionately similar or smaller skulls relative to body mass. Larger−bodied ceratopsians evolved skulls that are 50% or more of trunk length—as measured without their expansive cranial frill. Although contemporaneous duck−billed dinosaurs also exhibit some positive allometry in the skull, skull length remains approximately 35% of trunk length. The evolution of extraordinary absolute and relative skull size among ceratopsians appears to have been driven by sexual selection and involved the tandem evolution of reduced head mobility and an obligate quadrupedal posture

A primitive ichthyosaur from the Lower Triassic of British Columbia, Canada

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Speech enhancement via mask-mapping based residual dense network

Abstract Masking-based and spectrum mapping-based methods are the two main algorithms of speech enhancement with deep neural network (DNN). But the mapping-based methods only utilizes the phase of noisy speech, which limits the upper bound of speech enhancement performance. Masking-based methods need to accurately estimate the masking which is still the key problem. Combining the advantages of above two types of methods, this paper proposes the speech enhancement algorithm MM-RDN (masking-mapping residual dense network) based on masking-mapping (MM) and residual dense network (RDN). Using the logarithmic power spectrogram (LPS) of consecutive frames, MM estimates the ideal ratio masking (IRM) matrix of consecutive frames. RDN can make full use of feature maps of all layers. Meanwhile, using the global residual learning to combine the shallow features and deep features, RDN obtains the global dense features from the LPS, thereby improves estimated accuracy of the IRM matrix. Simulations show that the proposed method achieves attractive speech enhancement performance in various acoustic environments. Specifically, in the untrained acoustic test with limited priors, e.g., unmatched signal-to-noise ratio (SNR) and unmatched noise category, MM-RDN can still outperform the existing convolutional recurrent network (CRN) method in the measures of perceptual evaluation of speech quality (PESQ) and other evaluation indexes. It indicates that the proposed algorithm is more generalized in untrained conditions