Deep Captioning with Multimodal Recurrent Neural Networks (m-RNN)

In this paper, we present a multimodal Recurrent Neural Network (m-RNN) model for generating novel image captions. It directly models the probability distribution of generating a word given previous words and an image. Image captions are generated by sampling from this distribution. The model consists of two sub-networks: a deep recurrent neural network for sentences and a deep convolutional network for images. These two sub-networks interact with each other in a multimodal layer to form the whole m-RNN model. The effectiveness of our model is validated on four benchmark datasets (IAPR TC-12, Flickr 8K, Flickr 30K and MS COCO). Our model outperforms the state-of-the-art methods. In addition, we apply the m-RNN model to retrieval tasks for retrieving images or sentences, and achieves significant performance improvement over the state-of-the-art methods which directly optimize the ranking objective function for retrieval. The project page of this work is: www.stat.ucla.edu/~junhua.mao/m-RNN.html .Comment: Add a simple strategy to boost the performance of image captioning task significantly. More details are shown in Section 8 of the paper. The code and related data are available at https://github.com/mjhucla/mRNN-CR ;. arXiv admin note: substantial text overlap with arXiv:1410.109

Mechanically Improved and Multifunctional CFRP Enabled by Resins with High Concentrations Epoxy-Functionalized Fluorographene Fillers

To meet the maximum potential of the mechanical properties of carbon fiber reinforced plastics (CFRP), stress transfer between the carbon fibers through the polymer matrix must be improved. A recent promising approach reportedly used reinforcing particles as fillers dispersed in the resin. Carbon based fillers are an excellent candidate for such reinforcing particles due to their intrinsically high mechanical properties, structure and chemical nature similar to carbon fiber and high aspect ratio. They have shown great potential in increasing the strength, elastic modulus and other mechanical properties of interest of CFRPs. However, a percolation threshold of ~1% of the carbon-based particle concentration in the base resin has generally been reported, beyond which the mechanical properties deteriorate due to particle agglomeration. As a result, the potential for further increase of the mechanical properties of CFRPs with carbon-based fillers is limited. We report a significant increase in the strength and elastic modulus of CFRPs, achieved with a novel reinforced thermoset resin that contains high loadings of epoxy-reacted fluorographene (ERFG) fillers. We found that the improvement in mechanical performance of CFRPs was correlated with increase in ERFG loading in the resin. Using a novel thermoset resin containing 10 wt% ERFG filler, CFRPs fabricated by wet layup technique with twill weaves showed a 19.6% and 17.7% increase in the elastic modulus and tensile strength respectively. In addition, because of graphene’s high thermal conductivity and high aspect ratio, the novel resin enhanced CFRPs possessed 59.3% higher through-plane thermal conductivity and an 81-fold reduction in the hydrogen permeability. The results of this study demonstrate that high loadings of functionalized particles dispersed in the resin is a viable path towards fabrication of improved, high-performance CFRP parts and systems

Group II Intron Protein Localization and Insertion Sites Are Affected by Polyphosphate

Mobile group II introns consist of a catalytic intron RNA and an intron-encoded protein with reverse transcriptase activity, which act together in a ribonucleoprotein particle to promote DNA integration during intron mobility. Previously, we found that the Lactococcus lactis Ll.LtrB intron-encoded protein (LtrA) expressed alone or with the intron RNA to form ribonucleoprotein particles localizes to bacterial cellular poles, potentially accounting for the intron's preferential insertion in the oriC and ter regions of the Escherichia coli chromosome. Here, by using cell microarrays and automated fluorescence microscopy to screen a transposon-insertion library, we identified five E. coli genes (gppA, uhpT, wcaK, ynbC, and zntR) whose disruption results in both an increased proportion of cells with more diffuse LtrA localization and a more uniform genomic distribution of Ll.LtrB-insertion sites. Surprisingly, we find that a common factor affecting LtrA localization in these and other disruptants is the accumulation of intracellular polyphosphate, which appears to bind LtrA and other basic proteins and delocalize them away from the poles. Our findings show that the intracellular localization of a group II intron-encoded protein is a major determinant of insertion-site preference. More generally, our results suggest that polyphosphate accumulation may provide a means of localizing proteins to different sites of action during cellular stress or entry into stationary phase, with potentially wide physiological consequences.This work was supported by National Institutes of Health R01 grants GM037949 to AML and GM076536 to EMM, Welch Foundation grants F-1607 to AML and F-1515 to EMM, and a Packard Foundation fellowship to EMM.Cellular and Molecular Biolog

Interfacial thermal conductance in graphene/black phosphorus heterogeneous structures

Graphene, as a passivation layer, can be used to protect the black phosphorus from the chemical reaction with surrounding oxygen and water. However, black phosphorus and graphene heterostructures have low efficiency of heat dissipation due to its intrinsic high thermal resistance at the interfaces. The accumulated energy from Joule heat has to be removed efficiently to avoid the malfunction of the devices. Therefore, it is of significance to investigate the interfacial thermal dissipation properties and manipulate the properties by interfacial engineering on demand. In this work, the interfacial thermal conductance between few-layer black phosphorus and graphene is studied extensively using molecular dynamics simulations. Two critical parameters, the critical power Pcr to maintain thermal stability and the maximum heat power density Pmax with which the system can be loaded, are identified. Our results show that interfacial thermal conductance can be effectively tuned in a wide range with external strains and interracial defects. The compressive strain can enhance the interfacial thermal conductance by one order of magnitude, while interface defects give a two-fold increase. These findings could provide guidelines in heat dissipation and interfacial engineering for thermal conductance manipulation of black phosphorus-graphene heterostructure-based devices.Comment: 33 pages, 22 figure

The Peptide MS/MS-Fragmentome: A Set of Predictable Fragment Ions with Highly Redundant Sequence Information

Upon low energy collision induced dissociation (CID), multiply protonated peptides generate a set of interdependent fragment ions detectable by MS/MS, the \u27[peptide]n+-fragmentome\u27. In particular dynamic fragmentation of [peptide]n+ ions in a collision cell generates information-rich MS/MS spectra. Currently, database-supported annotations of peptide MS/MS spectra are mainly based on a combination of peptide molecular weight and y type fragment ions, leaving a considerable number of good-quality peptide MS/MS spectra in proteomics studies unannotated. This situation may be improved by a more complete use of the structural information present in the [peptide]n+-fragmentome. The presentation provides an overview on the fragment ions of multiply protonated peptides and their connectivity, comprising a ions, b ions, y ions, and neutral loss reactions from the N-, and C-terminus, and internal b ions. In the low-mass region, the unique set of 19 y1 ions and of the 190 b2 ions carries a particular message, since these ions define the N-or C-terminal amino acid(s). Further, the b1 ions of the basic residues K, H, W, and R carry a specific N-terminal information, which is redundant to that contained in the corresponding b2 ions and in the N-terminal neutral loss peaks. Redundant information is also found in b and y ion series and in complementary b/y ion pairs. The latter are particularly abundant when generated by proline- or aspartate-induced backbone cleavages. From complementary b/y ion pairs the molecular weight of the precursor ion can be reconstructed to confirm or determine its molecular weight. This procedure is helpful in case a mixture of precursor ions is isolated or in case a precursor ion of very low abundance is isolated. Information about the precursor ion charge state is also delivered by precursor ion reconstruction using MS/MS data. In the analysis of covalently modified peptides, reporter ions are of particular importance. These ions can be used for mining of MS/MS data sets for the occurrence of selected modifications. Examples are presented for selected modifications, such as acetylation and phosphorylation. In phosphorylation analysis neutral loss reactions are highly important, and may also carry redundant information, when observed both from the molecular ion and from fragment ions. Search tools, which fully incorporate the current knowledge about the [peptide]n+-fragmentome will increase the scores of peptide/protein identifications by MS/MS and thus will increase the fraction of automatically assigned MS/MS spectra in proteomics studies