bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical Construction and Propulsion Analysis of a Rescue Underwater Robot in the case of Drowning Persons
Authors: Bonfitto Angelo , Amati Nicola
Published: April 2018

This paper presents the design of an unmanned and tele-operated robotized life-saving system aimed to work as a recovery tool in case of water-related disasters. The device is designed to save people in distress in the water, either conscious or unconscious, without exposing the rescuer’s life to risk. The data of in water accidents show that the greatest number of casualties occurs because of dangerous predicaments conducted by people who want to save other lives. All present solutions are based on aerial, surface or submarine systems needing a crew and able to save only conscious people. This paper intends to fill this gap in the literature by analyzing the main critical issues in the design of a marine autonomous rescue vehicle in terms of performance, capabilities of maneuver in rough sea conditions and the costs. The proposed robot is fully electric and tele-manipulated, from the shore in case of accidents near dry land, or directly from boats or helicopters if drowning is occurring in the open sea. The paper demonstrates the feasibility of a system and its readiness for prototyping phases while presenting a trade-off and cost analysis between six different configurations as well as illustrating in detail the design of the selected layout. The motivations behind the choice of diving strategy to tackle rough sea conditions are described along with the design and the numerical validations of the hydroplane and propulsion systems.
Separation of Upslope Flow over a Plateau
Authors: Hilel Goldshmid Roni , Bardoel Stef L. , Hocut Christopher M. , Zhong Qiang , Liberzon Dan , Fernando Harindra J. S.
Published: April 2018

A laboratory study was conducted in order to gain an understanding of thermal convection in a complex terrain that is characterized by a plateaued mountain. In particular, the separation of upslope (anabatic) flow over a two-dimensional uniform smooth slope, topped by a plateau, was considered. The working fluid was homogeneous water (neutral stratification). The topographic model was immersed in a large water tank with no mean flow. The entire topographic model was uniformly heated, and the width of the plateau, the slope angle, and the heating rate were varied. The upslope velocity field was measured by the Particle Tracking Velocimetry, aided by Feature Tracking Visualizations in order to detect the flow separation location. An analysis of the resulting flow showed a quantitative similarity to separating the upslope flow over steeper slopes, in the absence of a plateau when an effective angle that incorporates the normalized plateau width, the slope length, and the geometric slope angle, was used. Predictions for the dependence of the separation location and velocity on the geometry and heat flux were presented and compared with the existing data.
Targeting Epigenetic Aberrations in Pancreatic Cancer, a New Path to Improve Patient Outcomes?
Authors: Paradise Brooke D. , Barham Whitney , Fernandez-Zapico Martín E.
Published: April 2018

Pancreatic cancer has one of the highest mortality rates among all types of cancers. The disease is highly aggressive and typically diagnosed in late stage making it difficult to treat. Currently, the vast majority of therapeutic regimens have only modest curative effects, and most of them are in the surgical/neo-adjuvant setting. There is a great need for new and more effective treatment strategies in common clinical practice. Previously, pathogenesis of pancreatic cancer was attributed solely to genetic mutations; however, recent advancements in the field have demonstrated that aberrant activation of epigenetic pathways contributes significantly to the pathogenesis of the disease. The identification of these aberrant activated epigenetic pathways has revealed enticing targets for the use of epigenetic inhibitors to mitigate the phenotypic changes driven by these cascades. These pathways have been found to be responsible for overactivation of growth signaling pathways and silencing of tumor suppressors and other cell cycle checkpoints. Furthermore, new miRNA signatures have been uncovered in pancreatic ductal adenocarcinoma (PDAC) patients, further widening the window for therapeutic opportunity. There has been success in preclinical settings using both epigenetic inhibitors as well as miRNAs to slow disease progression and eliminate diseased tissues. In addition to their utility as anti-proliferative agents, the pharmacological inhibitors that target epigenetic regulators (referred to here as readers, writers, and erasers for their ability to recognize, deposit, and remove post-translational modifications) have the potential to reconfigure the epigenetic landscape of diseased cells and disrupt the cancerous phenotype. The potential to “reprogram” cancer cells to revert them to a healthy state presents great promise and merits further investigation.
One-Pot, One-Step Production of Dietary Nucleotides by Magnetic Biocatalysts
Authors: Del Arco Jon , Martínez-Pascual Sara , Clemente-Suárez Vicente Javier , Corral Octavio Jorge , Jordaan Justin , Hormigo Daniel , Perona Almudena , Fernández-Lucas Jesús
Published: April 2018

The enzymatic synthesis of nucleotides offers several advantages over traditional multistep chemical methods, such as stereoselectivity, regioselectivity, enantioselectivity, simple downstream processing, and the use of mild reaction conditions. However, in order to scale up these bioprocesses, several drawbacks, such as the low enzyme stability and recycling, must be considered. Enzyme immobilization may overcome these cost-related problems by enhancing protein stability and facilitating the separation of products. In this regard, tetrameric hypoxanthine–guanine–xanthine phosphoribosyltransferase (HGXPRT) from Thermus thermophilus HB8 was covalently immobilized onto glutaraldehyde-activated MagReSyn®Amine magnetic iron oxide porous microparticles (MTtHGXPRT). In this context, two different strategies were followed: (a) an enzyme immobilization through its N-terminus residues at pH 8.5 (derivatives MTtHGXPRT1-3); and (b) a multipoint covalent immobilization through the surface lysine residues at pH 10 (derivatives MTtHGXPRT4-5). The immobilized derivatives of MTtHGXPRT3 (activity 1581 international units per gram of support, IU/g; retained activity 29%) and MTtHGXPRT5 (activity 1108 IU/g; retained activity 23%) displayed the best wet biocatalyst activity, and retained activity values in the enzymatic synthesis of inosine-5′-monophosphate (IMP). In addition, the dependence of the activities and stabilities of both derivatives on pH and temperature was tested, as well as their reusability potential. Taking these results into account, MTtHGXPRT3 was chosen as the best biocatalyst (negligible loss of activity at 60 °C during 24 h; reusable up to seven cycles). Finally, as proof of concept, the enzymatic production of dietary nucleotides from high concentrations of low soluble bases was achieved.
Evaluation of Small-Scale Fishers’ Perceptions on Climate Change and Their Coping Strategies: Insights from Lake Malawi
Authors: Limuwa Moses Majid , Sitaula Bishal Kumar , Njaya Friday , Storebakken Trond
Published: April 2018

The effects of climate change have negatively affected Malawi’s agricultural production. In this context, fisheries have been providing alternative livelihoods. However, there is a knowledge gap around the responses of small-scale fishers to climate-related changes. Therefore, a study was conducted on the Western shores of Lake Malawi between August 2015 and April 2016. The study evaluated the perceived effects of climate change on small-scale fishers and their coping strategies by employing a wide range of methods for data collection and analysis. The study used explorative surveys, household surveys, focus group discussions and key informant interviews to collect data. The study randomly sampled 112 household heads who owned either fishing gear or a fishing vessel or both. Content analysis for themes was used to analyse the qualitative data. The Mann–Kendal Test was used to analyse trends in meteorological data, and binary logistic regression was used to determine factors that influence coping with low fish catches. Despite the respondents noticing an increased incidence of extreme weather events and low fish catches, their perceptions could not be validated using time series meteorological data. However, such perceptions were influenced by experience from long-time exposure to extreme weather events and to low fish catches. The majority of the fishers had adjusted to these changes by increasing their fishing time, using highly efficient illegal fishing nets, expanding farming land, operating small businesses and undertaking casual labour in agriculture and fishing activities. The fishers’ propensity to adjust to these changes increased due to the presence of the following factors: older age of household head, higher education level, being married and having an annual income. In contrast, being a member of fish conservation club decreased the probability of adjusting. This study emphasizes the need to be cautious when defining and framing perceptions of local communities on extreme weather events as data obtained could be misleading. Furthermore, a multi-sectoral approach to balance sustainable livelihoods and management of fisheries is needed. These findings provide theoretical and practical lessons that can inform design, planning and implementation of policies that enhance adaptive capacity in fisheries and promote sustainable livelihoods in sub-Saharan Africa.
Asymptotic Behavior of Exact Exchange for Slabs: Beyond the Leading Order
Authors: Engel Eberhard
Published: April 2018

Far outside the surface of slabs, the exact exchange (EXX) potential v x falls off as − 1 / z , if z denotes the direction perpendicular to the surface and the slab is localized around z = 0 . Similarly, the EXX energy density e x behaves as − n / ( 2 z ) , where n is the electron density. Here, an alternative proof of these relations is given, in which the Coulomb singularity in the EXX energy is treated in a particularly careful fashion. This new approach allows the derivation of the next-to-leading order contributions to the asymptotic v x and e x . It turns out that in both cases, the corrections are proportional to 1 / z 2 in general.
Application of Multiscale Entropy in Mechanical Fault Diagnosis of High Voltage Circuit Breaker
Authors: Dou Longjiang , Wan Shuting , Zhan Changgeng
Published: April 2018

Mechanical fault diagnosis of a circuit breaker can help improve the reliability of power systems. Therefore, a new method based on multiscale entropy (MSE) and the support vector machine (SVM) is proposed to diagnose the fault in high voltage circuit breakers. First, Variational Mode Decomposition (VMD) is used to process the high voltage circuit breaker’s vibration signals, and the reconstructed signal can eliminate the effect of noise. Second, the multiscale entropy of the reconstructed signal is calculated and selected as a feature vector. Finally, based on the feature vector, the fault identification and classification are realized by SVM. The feature vector constructed by multiscale entropy is compared with other feature vectors to illustrate the superiority of the proposed method. Through experimentation on a 35 kV SF6 circuit breaker, the feasibility and applicability of the proposed method for fault diagnosis are verified.
Liquid Lipase-Catalyzed Esterification of Oleic Acid with Methanol for Biodiesel Production in the Presence of Superabsorbent Polymer: Optimization by Using Response Surface Methodology
Authors: Nguyen Hoang Chinh , Huong Dinh Thi My , Juan Horng-Yi , Su Chia-Hung , Chien Chien-Chung
Published: April 2018

Liquid lipase-catalyzed esterification of fatty acids with methanol is a promising process for biodiesel production. However, water by-product from this process favors the reverse reaction, thus reducing the reaction yield. To address this, superabsorbent polymer (SAP) was used as a water-removal agent in the esterification in this study. SAP significantly enhanced the conversion yield compared with the reaction without SAP. The lipase-catalyzed esterification in the presence of SAP was then optimized by response surface methodology to maximize the reaction conversion. A maximum conversion of 96.73% was obtained at a temperature of 35.25 °C, methanol to oleic acid molar ratio of 3.44:1, SAP loading of 10.55%, and enzyme loading of 11.98%. Under these conditions, the Eversa Transform lipase could only be reused once. This study suggests that the liquid lipase-catalyzed esterification of fatty acids using SAP as a water-removal agent is an efficient process for producing biodiesel.
Characteristics of Negative Streamer Development in Ester Liquids and Mineral Oil in a Point-To-Sphere Electrode System with a Pressboard Barrier
Authors: Rozga Pawel , Stanek Marcin , Pasternak Bartlomiej
Published: April 2018

This article presents the results of the studies on negative streamer propagation in a point-to-sphere electrode system with a pressboard barrier placed between them. The proposed electrode system gave the opportunity to assess the influence of the insulating barrier on streamer development in the conditions close to the actual transformer insulating system where the liquid gap is typically divided in parts by using pressboard barriers. The studies were performed for five commercial dielectric liquids. Among them two were biodegradable synthetic esters and two were biodegradable natural esters. Mineral oil, as the fifth liquid, was used for comparison. The measurements were based on electrical and optical experimental techniques. From the results obtained it may be concluded that, independently of the liquids tested, the electrical strength of the insulating system considered was increased by about 50%. In the case of streamer development assessed using photomultiplier-based light registration it is not possible to indicate clearly which of the liquids tested is better under the conditions of the experiment. In all cases streamers always developed slowly (2nd mode) at all voltage levels applied during the studies. In turn, the intensity of the discharge processes, comparing the same voltage levels, was mostly higher when streamers developed in ester liquids, however, the differences noticed were minimal.
Optimal Control Strategy for Series Hybrid Electric Vehicles in the Warm-Up Process
Authors: Wang Da , Song Chuanxue , Shao Yulong , Song Shixin , Peng Silun , Xiao Feng
Published: April 2018

To address the problems of low efficiency and high fuel consumption during the cold start and warm-up processes of internal combustion engines, a series hybrid electric vehicle was selected as the research object and two optimal control strategies were designed. A bench test was performed to determine the following: (a) the influence of engine coolant temperature on effective thermal efficiency; and (b) the relationship between engine operating conditions and coolant temperature increase rate. On the basis of the test results, two sets of warm-up process optimization control strategies were designed using a dynamic programming method and a fuzzy control method based on equivalent consumption minimization strategy (ECMS). The test results show that the fuzzy control method for the coolant temperature can effectively shorten the time required to warm up the engine, and the energy consumption of warm-up process can be reduced by nearly 10% through the dynamic programming method.
Large Swing Behavior of Overhead Transmission Lines under Rain-Load Conditions
Authors: Zhou Chao , Yin Jiaqi , Liu Yibing
Published: April 2018

In recent years, flashover accidents caused by large swings of overhead conductors that frequently occurred under rain-wind condition, greatly jeopardized the normal operation of power transmission systems. However, the large swing mechanism of overhead conductor under the simultaneous occurrence of rain and wind is not clear yet. Thus, a unified model is proposed with derived stability criterion to analyze the large swing of the overhead conductor. The analytical model is solved by finite element method with the aerodynamic coefficients obtained from simulated rain-wind tests, taking into account the effect of wind velocities, upper rivulet motion, rainfall rates, and rain loads on the large swings of overhead transmission lines. The results show that the proposed model can capture main features of the large swing of overhead conductor, this swing being probably due to the upper rivulet’s motion, by which negative aerodynamic damping occurs at a certain range of wind velocity (10 m/s). Furthermore, the peak swing amplitude of the overhead conductors under rain-wind condition is larger than that under wind only, and the rain loads cannot be neglected.
Protection Scheme of a Last Mile Active LVDC Distribution Network with Reclosing Option
Authors: Jamali Saeed Zaman , Bukhari Syed Basit Ali , Khan Muhammad Omer , Mehdi Muhammad , Noh Chul-Ho , Gwon Gi-Hyeon , Kim Chul-Hwan
Published: April 2018

A low voltage direct current (LVDC) distribution network is a promising technology to meet the standards of future energy demands for smart loads. An LVDC distribution network can not only supply efficient, smooth and clean energy, but also makes the integration of renewable energy resources in the distribution system easy. A major obstacle in the implementation of the LVDC distribution network is the protection of the network during abnormal grid conditions, such as transients and faults. This paper analyzes DC fault characteristics considering an LVDC distribution network, highlights the worst case scenario during a fault and protection related issues and proposes the protection schemes for the LVDC network. In the proposed protection scheme, a fault is detected and located through superimposed components. To minimize the effect of the DC fault on the distribution network, distributed fault current limiters are introduced and the final decision to disconnect or reconnect the affected line is made on the basis of the type of fault. In addition, a reclosing scheme for a temporary fault is proposed to avoid high inrush currents and false tripping, which eventually increases the reliability. A fast communication-based backup protection is also suggested, and to reduce dependency, a secondary backup is used in the case of communication delay or failure. The proposed scheme is verified using the modified IEEE 13 node test system, which is implemented in ATPDraw. The results show that the proposed scheme can successfully detect, locate and limit a DC fault in an LVDC distribution network with different fault resistances or locations. Moreover, the network is restored successfully in the case of temporary faults.
A Cross-Shape Coil Structure for Use in Wireless Power Applications
Authors: Sis Seyit Ahmet , Orta Emre
Published: April 2018

This paper presents a novel coil structure employing two parallel-connected subunit rectangular coils. The structure is based on the fact that the rectangular coils are less sensitive to misalignment along its longer side. Therefore, two identical subunit rectangular coils are vertically-oriented to one another and connected in parallel to form a cross-shape coil. The cross-shape coils have the advantage of better misalignment tolerance as compared to circular and square coils with similar footprints at the cost of an increased wire usage. Electromagnetic simulations and experiments on various small-sized coils are performed to verify the advantages of the proposed coil structure. Based on the simulation and measurement results, cross-shape coils exhibit not only better tolerance to misalignment, but also smaller self-inductance values resulting in larger coupling coefficients as compared to square and circular coils. A large cross-shape coil pair consisting of 100 × 70 cm subunit rectangles are fabricated with copper tubes and utilized in a frequency-tuned wireless power transfer system. When coils are separated by 17 cm, a near constant efficiency of more than 89% up to 15 cm misalignment along x- or y-directions and 13 cm along diagonal direction is obtained in the frequency-tuned system.
An Optimisation Study on Integrating and Incentivising Thermal Energy Storage (TES) in a Dwelling Energy System
Authors: Oluleye Gbemi , Allison John , Kelly Nicolas , Hawkes Adam D.
Published: April 2018

In spite of the benefits from thermal energy storage (TES) integration in dwellings, the penetration rate in Europe is 5%. Effective fiscal policies are necessary to accelerate deployment. However, there is currently no direct support for TES in buildings compared to support for electricity storage. This could be due to lack of evidence to support incentivisation. In this study, a novel systematic framework is developed to provide a case in support of TES incentivisation. The model determines the costs, CO2 emissions, dispatch strategy and sizes of technologies, and TES for a domestic user under policy neutral and policy intensive scenarios. The model is applied to different building types in the UK. The model is applied to a case study for a detached dwelling in the UK (floor area of 122 m2), where heat demand is satisfied by a boiler and electricity imported from the grid. Results show that under a policy neutral scenario, integrating a micro-Combined Heat and Power (CHP) reduces the primary energy demand by 11%, CO2 emissions by 21%, but with a 16 year payback. Additional benefits from TES integration can pay for the investment within the first 9 years, reducing to 3.5–6 years when the CO2 levy is accounted for. Under a policy intensive scenario (for example considering the Feed in Tariff (FIT)), primary energy demand and CO2 emissions reduce by 17 and 33% respectively with a 5 year payback. In this case, the additional benefits for TES integration can pay for the investment in TES within the first 2 years. The framework developed is a useful tool is determining the role TES in decarbonising domestic energy systems.
Ultra-Short-Term Wind-Power Forecasting Based on the Weighted Random Forest Optimized by the Niche Immune Lion Algorithm
Authors: Niu Dongxiao , Pu Di , Dai Shuyu
Published: April 2018

The continuous increase in energy consumption has made the potential of wind-power generation tremendous. However, the obvious intermittency and randomness of wind speed results in the fluctuation of the output power in a wind farm, seriously affecting the power quality. Therefore, the accurate prediction of wind power in advance can improve the ability of wind-power integration and enhance the reliability of the power system. In this paper, a model of wavelet decomposition (WD) and weighted random forest (WRF) optimized by the niche immune lion algorithm (NILA-WRF) is presented for ultra-short-term wind power prediction. Firstly, the original serials of wind speed and power are decomposed into several sub-serials by WD because the original serials have no obvious day characteristics. Then, the model parameters are set and the model trained with the sub-serials of wind speed and wind power decomposed. Finally, the WD-NILA-WRF model is used to predict the wind power of the relative sub-serials and the result is reconstructed to obtain the final prediction result. The WD-NILA-WRF model combines the advantage of each single model, which uses WD for signal de-noising, and uses the niche immune lion algorithm (NILA) to improve the model’s optimization efficiency. In this paper, two empirical analyses are carried out to prove the accuracy of the model, and the experimental results verify the proposed model’s validity and superiority compared with the back propagation neural network (BP neural network), support vector machine (SVM), RF and NILA-RF, indicating that the proposed method is superior in cases influenced by noise and unstable factors, and possesses an excellent generalization ability and robustness.
Volcanic Plumes: Impacts on the Atmosphere and Insights into Volcanic Processes
Authors: McGonigle Andrew J. S. , Sellitto Pasquale , Salerno Giuseppe G.
Published: April 2018

Here we introduce a Special Issue of Geosciences focused on the scientific research field of ‘Volcanic Plumes: Impacts on the atmosphere and insights into volcanic processes’ [...]
Exploring microRNA Biomarker for Amyotrophic Lateral Sclerosis
Authors: Taguchi Y.-h. , Wang Hsiuying
Published: April 2018

Amyotrophic lateral sclerosis (ALS) is among the severe neuro degenerative diseases that lack widely available effective treatments. As the disease progresses, patients lose the control of voluntary muscles. Although the neuronal degeneration is the cause of this disease, the failure mechanism is still unknown. In order to seek genetic mechanisms that initiate and progress ALS, the association of microRNA (miRNA) expression with this disease was considered. Serum miRNAs from healthy controls, sporadic ALS (sALS), familial ALS (fALS) and ALS mutation carriers were investigated. Principal component analysis (PCA)-based unsupervised feature extraction (FE) was applied to these serum miRNA profiles. As a result, we predict miRNAs that can discriminate patients from healthy controls with high accuracy. Thus, these miRNAs can be potential prognosis miRNA biomarkers for ALS.
Decellularized Diaphragmatic Muscle Drives a Constructive Angiogenic Response In Vivo
Authors: Alvarèz Fallas Mario Enrique , Piccoli Martina , Franzin Chiara , Sgrò Alberto , Dedja Arben , Urbani Luca , Bertin Enrica , Trevisan Caterina , Gamba Piergiorgio , Burns Alan J. , De Coppi Paolo , Pozzobon Michela
Published: April 2018

Skeletal muscle tissue engineering (TE) aims to efficiently repair large congenital and acquired defects. Biological acellular scaffolds are considered a good tool for TE, as decellularization allows structural preservation of tissue extracellular matrix (ECM) and conservation of its unique cytokine reservoir and the ability to support angiogenesis, cell viability, and proliferation. This represents a major advantage compared to synthetic scaffolds, which can acquire these features only after modification and show limited biocompatibility. In this work, we describe the ability of a skeletal muscle acellular scaffold to promote vascularization both ex vivo and in vivo. Specifically, chicken chorioallantoic membrane assay and protein array confirmed the presence of pro-angiogenic molecules in the decellularized tissue such as HGF, VEGF, and SDF-1α. The acellular muscle was implanted in BL6/J mice both subcutaneously and ortotopically. In the first condition, the ECM-derived scaffold appeared vascularized 7 days post-implantation. When the decellularized diaphragm was ortotopically applied, newly formed blood vessels containing CD31+, αSMA+, and vWF+ cells were visible inside the scaffold. Systemic injection of Evans Blue proved function and perfusion of the new vessels, underlying a tissue-regenerative activation. On the contrary, the implantation of a synthetic matrix made of polytetrafluoroethylene used as control was only surrounded by vWF+ cells, with no cell migration inside the scaffold and clear foreign body reaction (giant cells were visible). The molecular profile and the analysis of macrophages confirmed the tendency of the synthetic scaffold to enhance inflammation instead of regeneration. In conclusion, we identified the angiogenic potential of a skeletal muscle-derived acellular scaffold and the pro-regenerative environment activated in vivo, showing clear evidence that the decellularized diaphragm is a suitable candidate for skeletal muscle tissue engineering and regeneration.
Quantitative Changes in the Transcription of Phytohormone-Related Genes: Some Transcription Factors Are Major Causes of the Wheat Mutant dmc Not Tillering
Authors: He Ruishi , Ni Yongjing , Li Junchang , Jiao Zhixin , Zhu Xinxin , Jiang Yumei , Li Qiaoyun , Niu Jishan
Published: April 2018

Tiller number is an important agronomic trait for grain yield of wheat (Triticum aestivum L.). A dwarf-monoculm wheat mutant (dmc) was obtained from cultivar Guomai 301 (wild type, WT). Here, we explored the molecular basis for the restrained tiller development of the mutant dmc. Two bulked samples of the mutant dmc (T1, T2 and T3) and WT (T4, T5 and T6) with three biological replicates were comparatively analyzed at the transcriptional level by bulked RNA sequencing (RNA-Seq). In total, 68.8 Gb data and 463 million reads were generated, 80% of which were mapped to the wheat reference genome of Chinese Spring. A total of 4904 differentially expressed genes (DEGs) were identified between the mutant dmc and WT. DEGs and their related major biological functions were characterized based on GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) categories. These results were confirmed by quantitatively analyzing the expression profiles of twelve selected DEGs via real-time qRT-PCR. The down-regulated gene expressions related to phytohormone syntheses of auxin, zeatin, cytokinin and some transcription factor (TF) families of TALE, and WOX might be the major causes of the mutant dmc, not tillering. Our work provides a foundation for subsequent tiller development research in the future.
Computational Characterization of Small Molecules Binding to the Human XPF Active Site and Virtual Screening to Identify Potential New DNA Repair Inhibitors Targeting the ERCC1-XPF Endonuclease
Authors: Gentile Francesco , Barakat Khaled H. , Tuszynski Jack A.
Published: April 2018

The DNA excision repair protein ERCC-1-DNA repair endonuclease XPF (ERCC1-XPF) is a heterodimeric endonuclease essential for the nucleotide excision repair (NER) DNA repair pathway. Although its activity is required to maintain genome integrity in healthy cells, ERCC1-XPF can counteract the effect of DNA-damaging therapies such as platinum-based chemotherapy in cancer cells. Therefore, a promising approach to enhance the effect of these therapies is to combine their use with small molecules, which can inhibit the repair mechanisms in cancer cells. Currently, there are no structures available for the catalytic site of the human ERCC1-XPF, which performs the metal-mediated cleavage of a DNA damaged strand at 5′. We adopted a homology modeling strategy to build a structural model of the human XPF nuclease domain which contained the active site and to extract dominant conformations of the domain using molecular dynamics simulations followed by clustering of the trajectory. We investigated the binding modes of known small molecule inhibitors targeting the active site to build a pharmacophore model. We then performed a virtual screening of the ZINC Is Not Commercial 15 (ZINC15) database to identify new ERCC1-XPF endonuclease inhibitors. Our work provides structural insights regarding the binding mode of small molecules targeting the ERCC1-XPF active site that can be used to rationally optimize such compounds. We also propose a set of new potential DNA repair inhibitors to be considered for combination cancer therapy strategies.
Towards Understanding Plant Calcium Signaling through Calmodulin-Like Proteins: A Biochemical and Structural Perspective
Authors: La Verde Valentina , Dominici Paola , Astegno Alessandra
Published: April 2018

Ca2+ ions play a key role in a wide variety of environmental responses and developmental processes in plants, and several protein families with Ca2+-binding domains have evolved to meet these needs, including calmodulin (CaM) and calmodulin-like proteins (CMLs). These proteins have no catalytic activity, but rather act as sensor relays that regulate downstream targets. While CaM is well-studied, CMLs remain poorly characterized at both the structural and functional levels, even if they are the largest class of Ca2+ sensors in plants. The major structural theme in CMLs consists of EF-hands, and variations in these domains are predicted to significantly contribute to the functional versatility of CMLs. Herein, we focus on recent advances in understanding the features of CMLs from biochemical and structural points of view. The analysis of the metal binding and structural properties of CMLs can provide valuable insight into how such a vast array of CML proteins can coexist, with no apparent functional redundancy, and how these proteins contribute to cellular signaling while maintaining properties that are distinct from CaM and other Ca2+ sensors. An overview of the principal techniques used to study the biochemical properties of these interesting Ca2+ sensors is also presented.
Building Realistic Mobility Models for Mobile Ad Hoc Networks
Authors: Pullin Adrian , Pattinson Colin , Kor Ah-Lian
Published: April 2018

A mobile ad hoc network (MANET) is a self-configuring wireless network in which each node could act as a router, as well as a data source or sink. Its application areas include battlefields and vehicular and disaster areas. Many techniques applied to infrastructure-based networks are less effective in MANETs, with routing being a particular challenge. This paper presents a rigorous study into simulation techniques for evaluating routing solutions for MANETs with the aim of producing more realistic simulation models and thereby, more accurate protocol evaluations. MANET simulations require models that reflect the world in which the MANET is to operate. Much of the published research uses movement models, such as the random waypoint (RWP) model, with arbitrary world sizes and node counts. This paper presents a technique for developing more realistic simulation models to test and evaluate MANET protocols. The technique is animation, which is applied to a realistic scenario to produce a model that accurately reflects the size and shape of the world, node count, movement patterns, and time period over which the MANET may operate. The animation technique has been used to develop a battlefield model based on established military tactics. Trace data has been used to build a model of maritime movements in the Irish Sea. Similar world models have been built using the random waypoint movement model for comparison. All models have been built using the ns-2 simulator. These models have been used to compare the performance of three routing protocols: dynamic source routing (DSR), destination-sequenced distance-vector routing (DSDV), and ad hoc n-demand distance vector routing (AODV). The findings reveal that protocol performance is dependent on the model used. In particular, it is shown that RWP models do not reflect the performance of these protocols under realistic circumstances, and protocol selection is subject to the scenario to which it is applied. To conclude, it is possible to develop a range of techniques for modelling scenarios applicable to MANETs, and these simulation models could be utilised for the evaluation of routing protocols.
Investigation of the Financial Stability of S&P 500 Using Realized Volatility and Stock Returns Distribution
Authors: Akter Nahida , Nobi Ashadun
Published: April 2018

In this work, the financial data of 377 stocks of Standard & Poor’s 500 Index (S&P 500) from the years 1998–2012 with a 250-day time window were investigated by measuring realized stock returns and realized volatility. We examined the normal distribution and frequency distribution for both daily stock returns and volatility. We also determined the beta-coefficient and correlation among the stocks for 15 years and found that, during the crisis period, the beta-coefficient between the market index and stock’s prices and correlation among stock’s prices increased remarkably and decreased during the non-crisis period. We compared the stock volatility and stock returns for specific time periods i.e., non-crisis, before crisis and during crisis year in detail and found that the distribution behaviors of stock return prices has a better long-term effect that allows predictions of near-future market behavior than realized volatility of stock returns. Our detailed statistical analysis provides a valuable guideline for both researchers and market participants because it provides a significantly clearer comparison of the strengths and weaknesses of the two methods.
A Survey of ReRAM-Based Architectures for Processing-In-Memory and Neural Networks
Authors: Mittal Sparsh
Published: April 2018

As data movement operations and power-budget become key bottlenecks in the design of computing systems, the interest in unconventional approaches such as processing-in-memory (PIM), machine learning (ML), and especially neural network (NN)-based accelerators has grown significantly. Resistive random access memory (ReRAM) is a promising technology for efficiently architecting PIM- and NN-based accelerators due to its capabilities to work as both: High-density/low-energy storage and in-memory computation/search engine. In this paper, we present a survey of techniques for designing ReRAM-based PIM and NN architectures. By classifying the techniques based on key parameters, we underscore their similarities and differences. This paper will be valuable for computer architects, chip designers and researchers in the area of machine learning.
Efficacy of Aortic Valve Replacement through Full Sternotomy and Minimal Invasion (Ministernotomy)
Authors: Aliahmed Hammad M. A. , Karalius Rimantas , Valaika Arūnas , Grebelis Arimantas , Semėnienė Palmyra , Čypienė Rasa
Published: April 2018

Background: new minimally invasive sternotomy (mini-sternotomy) procedures have improved the treatment outcome and reduced the incidence of perioperative complications leading to improved patient satisfaction and a reduced cost of aortic valve replacement in comparison to the conventional median sternotomy (full sternotomy). The aim of this study is to compare and gain new insights into operative and early postoperative outcomes, long-term postoperative results, and 5-year survival rates after aortic valve replacement through a ministernotomy and full sternotomy. Methods: This is a retrospective study of patients who underwent an isolated replacement of the aortic valve via a full sternotomy or ministernotomy from 2011 to 2016. From 2011 to 2016, 426 cardiac interventions were performed, 70 of which (16.4%) were of the ministernotomy and 356 (83.6%) of the full sternotomy. Through propensity score matching, 70 patients who underwent the ministernotomy (ministernotomy group) were compared with 70 patients who underwent the full sternotomy (control group). Results: in the propensity matching cohort, no statistical difference in operative time was noted (p = 0.856). The ministernotomy had longer cross clamp (88.7 ± 20.7 vs. 80.3 ± 24.6 min, p = 0.007) and bypass (144.0 ± 29.9 vs. 132.9 ± 44.9 min, p = 0.049) times, less ventilation time (9.7 ± 1.7 vs. 11.7 ± 1.4 h, p < 0.001), shorter hospital stay (18.3 ± 1.9 vs. 21.9 ± 1.9 days, p = 0.012), less 24-h chest tube drainage (256.2 ± 28.6 vs. 407.3 ± 40.37 mL, p < 0.001), fewer corrections of coagulopathy (p < 0.001), fewer patients receiving catecholamine (5.71 vs. 30.0%, p < 0.001) and better cosmetic results (p < 0.001). Moreover, the number of patients without complaints at 1 year after the operation was significantly greater in the ministernotomy group (p = 0.002), and no significant differences in the 5-year survival between the groups were observed. In the overall cohort, the ministernotomy had longer cross clamp times (88.7 ± 20.7 vs. 79.9 ± 24.8 min, p < 0.001), longer operative times (263.5 ± 62.0 vs. 246.7 ± 74.2 min, p = 0.037) and bypass times (144.0 ± 29.9 vs. 132.7 ± 44.5 min, p = 0.026), lower incidence of 30-day mortality (1(1.4) vs. 13(3.7), p = 0.022), shorter hospital stays post-surgery p = 0.025, less 24-h chest tube drainage, p < 0.001, and fewer corrections of coagulopathy (p < 0.001). Conclusions: the ministernotomy has a number of advantages compared with the full sternotomy and thus could be a better approach for aortic valve replacement.
Characteristics and Management of Community-Acquired Pneumonia in the Era of Global Aging
Authors: Cillóniz Catia , Rodríguez-Hurtado Diana , Torres Antoni
Published: April 2018

Community-acquired pneumonia (CAP) can occur at any time of life, but its incidence and risk of death are linked to increasing age. CAP in the elderly is a major health problem associated with high rates of readmission, morbidity, and mortality. Since the clinical presentation of pneumonia in the elderly may be atypical, clinicians should suspect pneumonia in older patients presenting symptoms such as falls and altered mental status, fatigue, lethargy, delirium, anorexia, in order to avoid the complications associated with delayed diagnosis and therapy. Streptococcus pneumoniae remains the most frequently reported pathogen in this population. However, particular attention should be paid to patients with risk factors for multidrug resistant pathogens, because a large proportion of elderly persons present multimorbidity. Vaccination is one of the most important preventive approaches for CAP in the elderly. In addition, lifestyle-tailored interventions for different modifiable risk factors will help to reduce the risk of pneumonia in elderly persons. Surveillance of etiological pathogens may improve vaccination policies in this population.
Microstructure and Anisotropy of Plastic Properties of Thermomechanically-Processed HSLA-Type Steel Plates
Authors: Opiela Marek , Grajcar Adam
Published: April 2018

The paper presents the investigation results of the impact of shear bands on microstructure, mechanical properties, and anisotropy of plastic properties of HSLA (high-strength, low-alloy) type steel plates, produced in the process of thermomechanical rolling. A lack of conditions ensuring the complete static recrystallization between successive roll passes leads to localization of plastic deformation and formation of shear bands in dynamically-recrystallized austenite enriched with carbon and other interstitial elements, which transform into carbide segregation bands during tempering. These bands are the cause of low impact resistance of rolled plates, especially in the transverse direction, and the high degree of anisotropy of plastic properties in the plates.
Microstructure and Properties of Friction Stir Welded 2219 Aluminum Alloy under Heat Treatment and Electromagnetic Forming Process
Authors: Wang Zeyu , Huang Liang , Li Jianjun , Li Xiaoxia , Zhu Hui , Ma Fei , Ma Huijuan , Cui Junjia
Published: April 2018

Among available processing technologies of heat-treatable aluminum alloys such as the 2219 aluminum alloy, the use of both friction stir welding (FSW) as joining technology and electromagnetic forming (EMF) for plastic formation technology have obvious advantages and successful applications. Therefore, significant potential exists for these processing technologies, both of which can be used on the 2219 aluminum alloy, to manufacture large-scale, thin-wall parts in the astronautic industry. The microstructure and mechanical properties of 2219 aluminum alloy under a process which compounded FSW, heat treatment, and EMF were investigated by means of a tensile test as well as via both an optical microscope (OM) and scanning electron microscope (SEM). The results show that the reduction of strength, which was caused during the FSW process, can be recovered effectively. This can be accomplished by a post-welding heat treatment composed of solid solution and aging. However, ductility was still reduced after heat treatment. Under the processing technology composed of FSW, heat treatment, and EMF, the forming limit of the 2219 aluminum alloy decreased distinctly due to the poor ductility of the welding joint. A ribbon pattern was found on the fractured surface of welded 2219 aluminum alloy after EMF treatment, which was formed due to the banded structure caused by the FSW process. Because of the effects of induced eddy current in the EMF process, the material fractured, forming a unique structure which manifested as a molten surface appearance under SEM observation.
Fatigue Strength Assessment of Welded Mild Steel Joints Containing Bulk Imperfections
Authors: Leitner Martin , Murakami Yukitaka , Farajian Majid , Remes Heikki , Stoschka Michael
Published: April 2018

This work investigates the effect of gas pores, as bulk imperfections, on the fatigue strength of welded mild steel joints. Two test series containing different butt joint geometries and weld process parameters are included in order to achieve two variable types of pore sizes. Based on the √area-parameter by Murakami, the test series can be grouped into imperfections exhibiting √area < 1000 µm and √area > 1000 µm. Fatigue tests at a load stress ratio of R = 0.1 are performed, which act as comparison for the subsequent fatigue estimation. To assess the fatigue resistance, the approaches by Murakami, De Kazinczy, and Mitchell are utilized, which highlight certain differences in the applicability depending on the imperfection size. It is found that, on one hand, Murakami’s approach is well suitable for both small and large gas pores depending on the applied model parameters. On the other hand, the fatigue concepts by De Kazinczy and Mitchell are preferably practicable for large defects with √area > 1000 µm. In addition, the method by Mitchell incorporates the stress concentration factor of the imperfection, which can be numerically computed considering the size, shape, and location of the gas pore, as presented in this paper.
Recombinant Inga Laurina Trypsin Inhibitor (ILTI) Production in Komagataella Phaffii Confirms Its Potential Anti-Biofilm Effect and Reveals an Anti-Tumoral Activity
Authors: Carneiro Fábio C. , Weber Simone S. , Silva Osmar N. , Jacobowski Ana Cristina , Ramada Marcelo H. S. , Macedo Maria L. R. , Franco Octávio L. , Parachin Nádia S.
Published: April 2018

Protease inhibitors have a broad biotechnological application ranging from medical drugs to anti-microbial agents. The Inga laurina trypsin inhibitor (ILTI) previously showed a great in vitro inhibitory effect under the adherence of Staphylococcus species, being a strong candidate for use as an anti-biofilm agent. Nevertheless, this is found in small quantities in its sources, which impairs its utilization at an industrial scale. Within this context, heterologous production using recombinant microorganisms is one of the best options to scale up the recombinant protein production. Thus, this work aimed at utilizing Komagataella phaffii to produce recombinant ILTI. For this, the vector pPIC9K+ILTI was constructed and inserted into the genome of the yeast K. phaffii, strain GS115. The protein expression was highest after 48 h using methanol 1%. A matrix-assisted laser desorption ionization–time-of-flight (MALDI–TOF) analysis was performed to confirm the production of the recombinant ILTI and its activity was investigated trough inhibitory assays using the synthetic substrate Nα-Benzoyl-D,L-arginine p-nitroanilide hydrochloride (BAPNA). Finally, recombinant ILTI (rILTI) was used in assays, showing that there was no significant difference between native and recombinant ILTI in its inhibitory activity in biofilm formation. Anti-tumor assay against Ehrlich ascites tumor (EAT) cells showed that rILTI has a potential anti-tumoral effect, showing the same effect as Melittin when incubated for 48 h in concentrations above 25 µg/mL. All together the results suggests broad applications for rILTI.