Image Deblurring via an Adaptive Dictionary Learning Strategy

Recently, sparse representation has been applied to image deblurring. The dictionary is the fundamental part of it and the proper selection of dictionary is very important to achieve super performance. The global learned dictionary might achieve inferior performances since it could not mine the specific information such as the texture and edge which is contained in the blurred image. However, it is a computational burden to train a new dictionary for image deblurring which requires the whole image (or most parts) as input; training the dictionary on only a few patches would result in over-fitting. To address the problem, we instead propose an online adaption strategy to transfer the global learned dictionary to a specific image. In our deblurring algorithm, the sparse coefficients, latent image, blur kernel and the dictionary are updated alternatively. And in every step, the global learned dictionary is updated in an online form via sampling only a few training patches from the target noisy image. Since our adaptive dictionary exploits the specific information, our deblurring algorithm shows superior performance over other state-of-the-art algorithms.

In silico Identification of Serovar-Specific Genes for Salmonella Serotyping

Salmonella enterica subspecies enterica is a highly diverse subspecies with more than 1500 serovars and the ability to distinguish serovars within this group is vital for surveillance. With the development of whole-genome sequencing technology, serovar prediction by traditional serotyping is being replaced by molecular serotyping. Existing in silico serovar prediction approaches utilize surface antigen encoding genes, core genome MLST and serovar-specific gene markers or DNA fragments for serotyping. However, these serovar-specific gene markers or DNA fragments only distinguished a small number of serovars. In this study, we compared 2258 Salmonella accessory genomes to identify 414 candidate serovar-specific or lineage-specific gene markers for 106 serovars which includes 24 polyphyletic serovars and the paraphyletic serovar Enteritidis. A combination of several lineage-specific gene markers can be used for the clear identification of the polyphyletic serovars and the paraphyletic serovar. We designed and evaluated an in silico serovar prediction approach by screening 1089 genomes representing 106 serovars against a set of 131 serovar-specific gene markers. The presence or absence of one or more serovar-specific gene markers was used to predict the serovar of an isolate from genomic data. We show that serovar-specific gene markers have comparable accuracy to other in silico serotyping methods with 84.8% of isolates assigned to the correct serovar with no false positives (FP) and false negatives (FN) and 10.5% of isolates assigned to a small subset of serovars containing the correct serovar with varied FP. Combined, 95.3% of genomes were correctly assigned to a serovar. This approach would be useful as diagnosis moves to culture-independent and metagenomic methods as well as providing a third alternative to confirm other genome-based analyses. The identification of a set of gene markers may also be useful in the development of more cost-effective molecular assays designed to detect specific gene markers of the all major serovars in a region. These assays would be useful in serotyping isolates where cultures are no longer obtained and traditional serotyping is therefore impossible

Tetra­kis[(4-meth­oxy­carbon­yl)anilinium] hexa­chloridostannate(IV) dichloride

The asymmetric unit of the title compound, (C8H10NO2)4[SnCl6]Cl2, contains two (4-meth­oxy­carbon­yl)anilinium cations, one chloride anion and one half of a hexa­chlorido­stannate(IV) dianion situated on a twofold rotation axis. All aminium H atoms are involved in N—H⋯Cl hydrogen bonding, which consolidate the crystal packing along with weak C—H⋯O inter­actions

Seasonal dynamics of trace elements in sediment and seagrass tissues in the largest Zostera japonica habitat, the Yellow River Estuary, northern China

Trace element accumulation is an anthropogenic threat to seagrass ecosystems, which in turn may affect the health of humans who depend on these ecosystems. Trace element accumulation in seagrass meadows may vary temporally due to, e.g., seasonal patterns in sediment discharge from upstream areas. In addition, when several trace elements are present in sufficiently high concentrations, the risk of seagrass loss due to the cumulative impact of these trace elements is increased. To assess the seasonal variation and cumulative risk of trace element contamination to seagrass meadows, trace element (As, Cd, Cr, Cu, Pb, Hg, Mn and Zn) levels in surface sediment and seagrass tissues were measured in the largest Chinese Zostera japonica habitat, located in the Yellow River Estuary, at three sites and three seasons (fall, spring and summer) in 2014–2015. In all three seasons, trace element accumulation in the sediment exceeded background levels for Cd and Hg. Cumulative risk to Z. japonica habitat in the Yellow River Estuary, from all trace elements together, was assessed as “moderate” in all three seasons examined. Bioaccumulation of trace elements by seagrass tissues was highly variable between seasons and between above-ground and below-ground biomass. The variation in trace element concentration of seagrass tissues was much higher than the variation in trace element concentration of the sediment. In addition, for trace elements which tended to accumulate more in above-ground biomass than below-ground biomass (Cd and Mn), the ratio of above-ground to below-ground trace element concentration peaked at times corresponding to high water discharge and high sediment loads in the Yellow River Estuary. Overall, our results suggest that trace element accumulation in the sediment may not vary between seasons, but bioaccumulation in seagrass tissues is highly variable and may respond directly to trace elements in the water column

A New Study on the Parameter Relationships of Planetary Roller Screws

As a more powerful transmission device, planetary roller screws (PRSs) recently have received more attention, compared to conventional ball screws. However, due to the complicated and unclear relationships among the PRS components’ parameters, it is difficult to design high-quality PRSs. To facilitate the PRS design, a new study on the parameter relationships of PRS is conducted in this work. New models of the axial stiffness and the frictional moment of PRS are developed, and the relationships of the axial stiffness and the frictional moment in terms of contact angle, helical angle, and tooth number of the roller thread are investigated. This study could contribute to the research of PRS to improve its transmission performance, especially to increase its positioning accuracy

Molecular dynamics simulation on collision frictional properties of a molybdenum disulfide (MoS2) film in microgravity environment

In this paper, a collision friction model for a double-layer MoS2 film is proposed considering the microgravity induced collision in space environment. A modified REBO (Reactive Empirical Bond Order) potential is used to describe interactions among the atoms in the MoS2 film. The collision friction process of the MoS2 film is simulated by vibrations in the y and z directions, and the dependence of average friction force is analyzed. The influence of a single vibration in the y direction on the friction forces can be ignored, while the vibration in the z direction shows great influence. The effects of vibration frequency and amplitude on frictional behaviors of the MoS2 film are investigated. The average friction forces during the collision friction process correlate with the frequency of the vibration in the z direction, and the relationship shows four stages. As the frequency increases, average friction forces show low values in the first stage, and they are increased as the frequency in the second stage. In the third stage, the average friction forces are decreased, and they come to a stable level in the fourth stage. Increasing the vibration amplitude at different frequencies leads to an increase in average friction force, due to that the increased amplitude results in a high indentation depth. The puckering phenomenon occurs at a specific frequency, which is a reason that the average friction force is increased during this collision friction process

Examination of the Anaerobic Growth of Campylobacter concisus

Campylobacter concisus is an oral bacterium that is associated with intestinal diseases. C. concisus was previously described as a bacterium that requires H2-enriched microaerobic conditions for growth. The level of H2 in the oral cavity is extremely low, suggesting that C. concisus is unlikely to have a microaerobic growth there. In this study, the anaerobic growth of C. concisus was investigated. The growth of fifty-seven oral C. concisus strains and six enteric C. concisus strains under various atmospheric conditions including anaerobic conditions with and without H2 was examined. The atmospheric conditions were generated using commercially available gas-generation systems. C. concisus putative virulence proteins were identified using mass spectrometry analysis. Under anaerobic conditions, 92% of the oral C. concisus strains (52/57) and all six enteric strains grew without the presence of H2 and the presence of H2 greatly increased C. concisus growth. An oral C. concisus strain was found to express a number of putative virulence proteins and the expression levels of these proteins were not affected by H2. The levels of H2 appeared to affect the optimal growth of C. concisus. This study provides useful information in understanding the natural colonization site and pathogenicity of C. concisus