This paper reviews the technology used to enable commercial deployment of VCSELs at 25-28G and some of the device challenges that need to be addressed to enable the next generation of data rates.
A fast multigrid approach is presented for the analysis of thermal elastohydrodynamic lubrication (EHL) under rolling/sliding circular contacts at high loads and high slip ratios with low computing ...time on a personal computer. This fast solver combines directiteration, multigrid, Newton-Raphson, Gauss-Seidel iteration, and multilevel multi-integration methods into one working environment that can reduce the computational complexity from
O(n
3 to
O(nlnn) for the thermal EHL problem under rolling/sliding circular contacts. Since the couped Reynolds and energy equations are simultaneously solved by the Newton-Raphson scheme, the iteration for the convergence solution is less than those of the classical approach. Results show that thermal effects on the pressure profile and film thickness are significant for a wide range of loads, speeds and slip ratios. The maximum midfilm and surface temperature rise in the Hertzian contact region increases with increasing slip ratio, dimensionless speed, and load. The minimum film thickness decreases with increasing load and slip ratio, and decreasing dimensionless speed.
A reversible redox reaction ({Fe(NO)2}9 DNIC (NO)2Fe(N(Mes)(TMS))2− (4) ⇄ oxidized-form DNIC (NO)2Fe(N(Mes)(TMS))2 (5) (Mes = mesityl, TMS = trimethylsilane)), characterized by IR, UV–vis, 1H/15N ...NMR, SQUID, XAS, single-crystal X-ray structure, and DFT calculation, was demonstrated. The electronic structure of the oxidized-form DNIC 5 (S total = 0) may be best described as the delocalized aminyl radical (N(Mes)(TMS))22 –• stabilized by the electron-deficient {FeIII(NO–)2}9 motif, that is, substantial spin is delocalized onto the (N(Mes)(TMS))22 –• such that the highly covalent dinitrosyl iron core (DNIC) is preserved. In addition to IR, EPR (g ≈ 2.03 for {Fe(NO)2}9), single-crystal X-ray structure (Fe–N(O) and N–O bond distances), and Fe K-edge pre-edge energy (7113.1–7113.3 eV for {Fe(NO)2}10 vs 7113.4–7113.9 eV for {Fe(NO)2}9), the 15N NMR spectrum of Fe(15NO)2 was also explored to serve as an efficient tool to characterize and discriminate {Fe(NO)2}9 (δ 23.1–76.1 ppm) and {Fe(NO)2}10 (δ −7.8–25.0 ppm) DNICs. To the best of our knowledge, DNIC 5 is the first structurally characterized tetrahedral DNIC formulated as covalent–delocalized {FeIII(NO–)2}9–N(Mes)(TMS)2 –•. This result may explain why all tetrahedral DNICs containing monodentate-coordinate ligands isolated and characterized nowadays are confined in the {Fe(NO)2}9 and {Fe(NO)2}10 DNICs in chemistry and biology.
The Lipid A moiety of endotoxin potently activates TLR-4 dependent host innate immune responses. We demonstrate that Lipid-A mediated leukotriene biosynthesis regulates pathogen-associated molecular ...patterns (PAMP)-dependent macrophage activation. Stimulation of murine macrophages (RAW264.7) with E. coli 0111:B4 endotoxin (LPS) or Kdo2-lipid A (Lipid A) induced inflammation and Lipid A was sufficient to induce TLR-4 mediated macrophage inflammation and rapid ERK activation. The contribution of leukotriene biosynthesis was evaluated with a 5-lipoxygenase activating protein (FLAP) inhibitor, MK591. MK591 pre-treatment not only enhanced but also sustained ERK activation for up to 4 hours after LPS and Lipid A stimulation while inhibiting cell proliferation and enhancing cellular apoptosis. Leukotriene biosynthesis inhibition attenuated inflammation induced by either whole LPS or the Lipid A fraction. These responses were regulated by inhibition of the key biosynthesis enzymes for the proinflammatory eicosanoids, 5-lipoxygenase (5-LO), and cyclooxygenase-2 (COX-2) quantified by immunoblotting. Inhibition of leukotriene biosynthesis differentially regulated TLR-2 and TLR-4 cell surface expression assessed by flow cytometry, suggesting a close mechanistic association between TLR expression and 5-LO associated eicosanoid activity in activated macrophages. Furthermore, MK591 pre-treatment enhanced ERK activation and inhibited cell proliferation after LPS or Lipid A stimulation. These effects were regulated in part by increased apoptosis and modulation of cell surface TLR expression. Together, these data clarify the mechanistic association between 5-lipoxygenase activating protein-mediated leukotriene biosynthesis and 5-LO dependent eicosanoid metabolites in mediating the TLR-dependent inflammatory response after endotoxin exposure typical of bacterial sepsis.
With rapid growth of egocentric videos from wearable devices, the need for instant video event detection is emerging. Different from conventional video event detection, it requires more ...considerations on real-time event detection and immediate video recording due to the computational cost on wearable devices (e.g., Google Glass). Conventional work of video event detection analyzed video content in an offline process and it is time-consuming for visual analysis. Observing that wearable devices are usually along with sensors, we propose a novel approach for instant event detection in egocentric videos by leveraging sensor-based motion context. We compute statistics of sensor data as features. Next, we predict the user's current motion context by a hierarchical model, and then choose the corresponding ranking model to rate the importance score of the timestamp. With importance score provided in real-time, camera on the wearable device can dynamically record micro-videos without wasting power and storage. In addition, we collected a challenging daily-life dataset called EDS (Egocentric Daily-life Videos with Sensor Data), which contains both egocentric videos and sensor data recorded by Google Glass of different subjects. We evaluate the performance of our system on the EDS dataset, and the result shows that our method outperforms other baselines.
As the increasing popularity of touch-screen devices, retrieving images by hand-drawn sketch has become a trend. Human sketch can easily express some complex user intention such as the object shape. ...However, sketches are sometimes ambiguous due to different drawing styles and inter-class object shape ambiguity. Although adding text queries as semantic information can help removing the ambiguity of sketch, it requires a huge amount of efforts to annotate text tags to all database clipart images. We propose a method directly model the relationship between text and clipart images by the co-occurrence relationship between words and visual words, which improves traditional sketch-based image retrieval (SBIR), provides a baseline performance and obtains more relevant results in the condition that all images in database do not have any text tag. Experimental results show that our method really can help SBIR to get better retrieval result since it indeed learned semantic meaning from the ``word-visual word" (W-VW) co-occurrence relationship.
Escherichia coli transcription factor sigma 54 contains motifs that resemble closely those used for RNA polymerase II in mammalian cells, including two hydrophobic heptad repeats, a very acidic ...region and a glutamine-rich region. Triple changes in hydrophobic or multiple changes in acidic residues in Region III are known to severely impair core-binding ability. To investigate whether all the changes in triple mutants are necessary for core binding, site-directed mutagenesis was performed to create single and double mutants in the leucine or isoleucine residues in the heptad repeat in Region III. Single mutants showed no discernible loss of function. Double mutants showed partial protection of the -12 promoter element of the glnAp2 promoter due to the partial loss of their ability to bind core RNA polymerase. These mutations were deleterious to the function of sigma 54, which retained only 30-40% of wild-type mRNA levels. However, double mutants retained nearly normal ability to form open complexes. Two triple mutants created during previous work lost most, if not all, of their ability to bind core RNA polymerase, to protect the -12 promoter element of the glnAp2 promoter and to open the transcription start site. The two triple mutants produced about 20% or less than 10% of the wild-type transcripts from the glnAp2 promoter. These results demonstrate that the hydrophobic heptad repeat in Region III is essential for core RNA polymerase binding. Progressive loss of hydrophobicity of the hydrophobic heptad repeat in Region III of sigma 54 resulted in a progressive loss of core-binding ability, leading to the loss of -12 promoter element recognition and mRNA production.
Although many visualization tools provide us plenty of ways to view the data, users can not easily find the trending events and their explanation from the data. In this work, we address the issue by ...leveraging the real music streaming log data as an example to better understand a million-scale dataset. Trending event explanation turns out to be challenging when it comes to categorical log data. Therefore, we propose to use a learning-based method with an interface design to uncover the trending event compositions for time-series categorical log data, which can be extend to other datasets, e.g., the hashtags in social media. First, we perform "trending pool" operation to save the memory and time cost. Second, we apply sparse coding to learn important trending candidate combination sets instead of traditional brute-force way or manual investigation for generating combinations. Besides the contributions above, we also observe some interesting user behaviors by exploring detected trending candidate combinations visually through our interface.
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