Recovering Homography from Camera Captured Documents using Convolutional Neural Networks

Removing perspective distortion from hand held camera captured document images is one of the primitive tasks in document analysis, but unfortunately, no such method exists that can reliably remove the perspective distortion from document images automatically. In this paper, we propose a convolutional neural network based method for recovering homography from hand-held camera captured documents. Our proposed method works independent of document's underlying content and is trained end-to-end in a fully automatic way. Specifically, this paper makes following three contributions: Firstly, we introduce a large scale synthetic dataset for recovering homography from documents images captured under different geometric and photometric transformations; secondly, we show that a generic convolutional neural network based architecture can be successfully used for regressing the corners positions of documents captured under wild settings; thirdly, we show that L1 loss can be reliably used for corners regression. Our proposed method gives state-of-the-art performance on the tested datasets, and has potential to become an integral part of document analysis pipeline.Comment: 10 pages, 8 figure

Precipitation of Trichoderma reesei commercial cellulase preparations under standard enzymatic hydrolysis conditions for lignocelluloses

Comparative studies between commercial Trichoderma reesei cellulase preparations show that, depending on the preparation and loading, total protein precipitation can be as high as 30 % under standard hydrolysis conditions used for lignocellulosic materials. ATR-IR and SDS-PAGE data verify precipitates are protein-based and contain key cell wall hydrolyzing enzymes. Precipitation increased considerably with incubation temperature; roughly 50–150 % increase from 40 to 50 °C and 800 % greater at 60 °C. All of the reported protein losses translated into significant, and often drastic, losses in activity on related 4-nitrophenyl substrates. In addition, supplementation with the non-ionic surfactant PEG 6,000 decreased precipitation up to 80 % in 24 h precipitation levels. Protein precipitation is potentially substantial during enzymatic hydrolysis of lignocelluloses and should be accounted for during lignocellulose conversion process design, particularly when enzyme recycling is considered.This work was supported by the project "Demonstrating Industrial scale second generation bioethaol production-Kalundborg Cellulosic Ethanol Plant" under the EU FP7 framework program and the project "Development of improved second generation (2G) bioethanol technology to prepare for commercialization under the Danish Energy Technology and Demonstration Programme (EUDP)

The impact of hydrogen peroxide supply on LPMO activity and overall saccharification efficiency of a commercial cellulase cocktail

Background: The discovery of enzymes named lytic polysaccharide monooxygenases (LPMOs) has had a major impact on the efficiency of current commercial cellulase cocktails for saccharification of lignocellulosic biomass. However, the notion that LPMOs use molecular oxygen as a co-substrate and require two externally delivered electrons per catalytic cycle poses a challenge in the development of efficient large-scale industrial processes. Building on the recent discovery that H2O2, rather than O-2, is the co-substrate of LPMOs, we show here how cellulose degradation by the LPMO-containing commercial cellulase cocktail-Cellic (R) CTec2 can be controlled and boosted by supplying the reaction with H2O2. Results: The controlled supply of anaerobic hydrolysis reactions with H2O2 and sub-stoichiometric amounts of reductant increased apparent LPMO activity by almost two orders of magnitude compared to standard aerobic reactions utilizing O-2 and stoichiometric amounts of reductant. Improved LPMO activity was correlated with enhanced saccharification rates and yields for a model cellulosic substrate (Avicel) as well as industrial lignocellulosic substrates (sulfite-pulped Norway spruce and steam-exploded birch), although the magnitude of the effects was substrate dependent. Improvements in lignocellulose conversions were achieved at low H2O2 feeding rates (in the range of 90-600 mu M h(-1)). Tight control of LPMO reactions by controlled supply of H2O2 under anaerobic conditions was possible. Conclusion: We report saccharification rates and yields for a model substrate (Avicel) and industrial lignocellulosic substrates that, at low H2O2 feeding rates, are higher than those seen under standard aerobic conditions. In an industrial setting, controlling and supplying molecular oxygen and stoichiometric amounts of reductant are challenging. The present report shows that the use of small amounts of a liquid bulk chemical, H2O2, provides an alternative to the currently available processes, which likely is cheaper and more easy to control, while giving higher product yields

3.Observation of Earthquake Ground Motions and Strains

小特集：地盤・構造物系の地震応答および破壊機構 : 千葉実験所に完成した振動台および地震応答観測システムの概

Engineering chitinolytic activity into a cellulose-active lytic polysaccharide monooxygenase provides insights into substrate specificity

Lytic polysaccharide monooxygenases (LPMOs) catalyze oxidative cleavage of recalcitrant polysaccharides such as cellulose and chitin and play an important role in the enzymatic degradation of biomass. While it is clear that these monocopper enzymes have extended substrate-binding surfaces for interacting with their fibrous substrates, the structural determinants of LPMO substrate specificity remain largely unknown. To gain additional insight into substrate specificity in LPMOs, here we generated a mutant library of a cellulose-active family AA10 LPMO from Streptomyces coelicolor A3(2) (ScLPMO10C, also known as CelS2) having multiple substitutions at five positions on the substrate-binding surface that we identified by sequence comparisons. Screening of this library using a newly developed MS-based high-throughput assay helped identify multiple enzyme variants that contained four substitutions and exhibited significant chitinolytic activity and a concomitant decrease in cellulolytic activity. The chitin-active variants became more rapidly inactivated during catalysis than a natural chitin-active AA10 LPMO, an observation likely indicative of suboptimal substrate binding leading to autocatalytic oxidative damage of these variants. These results reveal several structural determinants of LPMO substrate specificity and underpin the notion that productive substrate binding by these enzymes is complex, depending on a multitude of amino acids located on the substrate-binding surface.publishedVersio

MOESM1 of The impact of hydrogen peroxide supply on LPMO activity and overall saccharification efficiency of a commercial cellulase cocktail

Additional file 1. The impact of hydrogen peroxide supply on LPMO activity and overall saccharification efficiency of a commercial cellulase cocktail. Figure S1. Stability of Glc4gemGlc and its impact on the results presented in this paper. Figure S2. Degradation of Glc4gemGlc during incubation under conditions similar to those during biomass saccharification in bioreactors

Demonstration-scale enzymatic saccharification of sulfite-pulped spruce with addition of hydrogen peroxide for LPMO activation

The saccharification of lignocellulosic materials like Norway spruce is challenging due to the recalcitrant nature of the biomass, and it requires optimized and efficient pretreatment and enzymatic hydrolysis processes to make it industrially feasible. In this study, we report successful enzymatic saccharification of sulfite-pulped spruce (Borregaard's BALI™ process) at demonstration scale, achieved through the controlled delivery of hydrogen peroxide (H2O2) for the activation of lytic polysaccharide monooxygenases (LPMOs) present in the cellulolytic enzyme preparation. We achieved 85% saccharification yield in 4 days using industrially relevant conditions – that is, an enzyme dose of 4% (w/w dry matter of substrate) of the commercial cellulase cocktail Cellic CTec3 and a substrate loading of 12% (w/w). Addition of H2O2 and the resulting controlled and high LPMO activity had a positive effect on the rate of saccharification and the final sugar titer. Clearly, the high LPMO activity was dependent on feeding the reactors with the LPMO co-substrate H2O2, as in situ generation of H2O2 from molecular oxygen was limited. These demonstration-scale experiments provide a solid basis for the use of H2O2 to improve enzymatic saccharification of lignocellulosic biomass at large industrial scale

Enzymatic degradation of sulfite-pulped softwoods and the role of LPMOs

Abstract Background Recent advances in the development of enzyme cocktails for degradation of lignocellulosic biomass, especially the discovery of lytic polysaccharide monooxygenases (LPMOs), have opened new perspectives for process design and optimization. Softwood biomass is an abundant resource in many parts of the world, including Scandinavia, but efficient pretreatment and subsequent enzymatic hydrolysis of softwoods are challenging. Sulfite pulping-based pretreatments, such as in the BALI™ process, yield substrates that are relatively easy to degrade. We have assessed how process conditions affect the efficiency of modern cellulase preparations in processing of such substrates. Results We show that efficient degradation of sulfite-pulped softwoods with modern, LPMO-containing cellulase preparations requires the use of conditions that promote LPMO activity, notably the presence of molecular oxygen and sufficient reducing power. Under LPMO activity-promoting conditions, glucan conversion after 48-h incubation with Cellic® CTec3 reached 73.7 and 84.3% for Norway spruce and loblolly pine, respectively, at an enzyme loading of 8 mg/g of glucan. The presence of free sulfite ions had a negative effect on hydrolysis efficiency. Lignosulfonates, produced from lignin during sulfite pretreatment, showed a potential to activate LPMOs. Spiking of Celluclast®, a cellulase cocktail with low LPMO activity, with monocomponent cellulases or an LPMO showed that the addition of the LPMO was clearly more beneficial than the addition of any classical cellulase. Addition of the LPMO in reactions with spruce increased the saccharification yield from approximately 60% to the levels obtained with Cellic® CTec3. Conclusions In this study, we have demonstrated the importance of LPMOs for efficient enzymatic degradation of sulfite-pulped softwood. We have also shown that to exploit the full potential of LPMO-rich cellulase preparations, conditions promoting LPMO activity, in particular the presence of oxygen and reducing equivalents are necessary, as is removal of residual sulfite from the pretreatment step. The use of lignosulfonates as reductants may reduce the costs related to the addition of small molecule reductants in sulfite pretreatment-based biorefineries