bluuebunny/crossref_metadata_2025 huggingface dataset:
Tribology and Surface Engineering
Authors: Lisiecki Aleksander
Published: October 2019

The Special Issue on Tribology and Surface Engineering includes nine research articles and one review article. It concerns a very important problem of resistance to wear and shaping the properties of the surface layers of different materials by different methods and technologies. The topics of the presented research articles include reactive direct current magnetron sputtering of silicon nitrides on implants, laser surface modification of aeroengine turbine blades, laser micro-texturing of titanium alloy to increase the tribological characteristics, electroplating of Cu–Sn composite coatings incorporated with Polytetrafluoroethylene (PTFE) and TiO2 particles, arc spraying of self-lubricous coatings, high velocity oxygen fuel (HVOF) spraying and gas nitriding of stainless steel coatings, HVOF spraying composite WC-Co coatings, testing of coatings deposited by physical vapour deposition (PVD), and also analysis of material removal and surface creation in wood sanding. The special issue provides valuable knowledge based on theoretical and empirical study in the field of coating technologies, as well as characterization of coatings, and wear phenomena.
Coordinate Scaling in Time-Independent Excited-State Density Functional Theory for Coulomb Systems
Authors: Nagy Ágnes
Published: October 2019

A time-independent density functional theory for excited states of Coulomb systems has recently been proposed in a series of papers. It has been revealed that the Coulomb density determines not only its Hamiltonian, but the degree of excitation as well. A universal functional valid for any excited state has been constructed. The excited-state Kohn–Sham equations bear resemblance to those of the ground-state theory. In this paper, it is studied how the excited-state functionals behave under coordinate scaling. A few relations for the scaled exchange, correlation, exchange-correlation, and kinetic functionals are presented. These relations are expected to be advantageous for designing approximate functionals.
Design of an LED Spot Light System with a Projection Distance of 10 km
Authors: Wu Chi-Shou , Chen Kuan-Yu , Lee Xuan-Hao , Lin Shih-Kang , Sun Ching-Cherng , Cai Jhih-You , Yang Tsung-Hsun , Yu Yeh-Wei
Published: October 2019

We designed a spot light system with an illumination range of 10 km. In the designed system, an appropriate white light-emitting diode (LED) was selected according to the exitance and injection power required. Subsequently, through a first-order optical design, the geometry of the lens and reflector was determined using geometrical calculation. Because the central illuminance of the projection spot of the reflector was 2.5 times that of the cover lens, we first considered the fabrication error of the reflector. According to the adjustment of the optimized distance between the white LED and reflector, we modified the design of the cover lens to fit the new location of the white LED. An LED spot light module containing 16 spot light units was used. The module’s power injection was only 68.2 W. Because of the excellent performance of the designed system in terms of the divergence angle of the projection beam and maximum luminous intensity, which were 1.6° and 2,840,000 cd, respectively, the projection distance of the LED spot light module was 3.37 Km, according to the ANSI regulation. Finally, a spot light system with nine modules and capable of achieving a projection distance of 10 km was successfully fabricated.
Requirements and Limitations of Thermal Drones for Effective Search and Rescue in Marine and Coastal Areas
Authors: Burke Claire , McWhirter Paul R. , Veitch-Michaelis Josh , McAree Owen , Pointon Harry A.G. , Wich Serge , Longmore Steve
Published: October 2019

Search and rescue (SAR) is a vital line of defense against unnecessary loss of life. However,in a potentially hazardous environment, it is important to balance the risks associated with SARaction. Drones have the potential to help with the efficiency, success rate and safety of SAR operationsas they can cover large or hard to access areas quickly. The addition of thermal cameras to the dronesprovides the potential for automated and reliable detection of people in need of rescue. We performeda pilot study with a thermal-equipped drone for SAR applications in Morecambe Bay. In a varietyof realistic SAR scenarios, we found that we could detect humans who would be in need of rescue,both by the naked eye and by a simple automated method. We explore the current advantages andlimitations of thermal drone systems, and outline the future path to a useful system for deploymentin real-life SAR.
Physical-Layer Security Analysis over M-Distributed Fading Channels
Authors: Lin Sheng-Hong , Lu Rong-Rong , Fu Xian-Tao , Tong An-Ling , Wang Jin-Yuan
Published: October 2019

In this paper, the physical layer security over the M-distributed fading channel is investigated. Initially, an exact expression of secrecy outage probability (SOP) is derived, which has an integral term. To get a closed-form expression, a lower bound of SOP is obtained. After that, the exact expression for the probability of strictly positive secrecy capacity (SPSC) is derived, which is in closed-form. Finally, an exact expression of ergodic secrecy capacity (ESC) is derived, which has two integral terms. To reduce its computational complexity, a closed-from expression for the lower bound of ESC is obtained. As special cases of M-distributed fading channels, the secure performance of the K, exponential, and Gamma-Gamma fading channels are also derived, respectively. Numerical results show that all theoretical results match well with Monte-Carlo simulation results. Specifically, when the average signal-to-noise ratio of main channel is larger than 40 dB, the relative errors for the lower bound of SOP, the probability of SPSC, and the lower bound of ESC are less than 1.936%, 6.753%, and 1.845%, respectively. This indicates that the derived theoretical expressions can be directly used to evaluate system performance without time-consuming simulations. Moreover, the derived results regarding parameters that influence the secrecy performance will enable system designers to quickly determine the optimal available parameter choices when facing different security risks.
Real-Time Object Detection in Remote Sensing Images Based on Visual Perception and Memory Reasoning
Authors: Hua Xia , Wang Xinqing , Rui Ting , Wang Dong , Shao Faming
Published: October 2019

Aiming at the real-time detection of multiple objects and micro-objects in large-scene remote sensing images, a cascaded convolutional neural network real-time object-detection framework for remote sensing images is proposed, which integrates visual perception and convolutional memory network reasoning. The detection framework is composed of two fully convolutional networks, namely, the strengthened object self-attention pre-screening fully convolutional network (SOSA-FCN) and the object accurate detection fully convolutional network (AD-FCN). SOSA-FCN introduces a self-attention module to extract attention feature maps and constructs a depth feature pyramid to optimize the attention feature maps by combining convolutional long-term and short-term memory networks. It guides the acquisition of potential sub-regions of the object in the scene, reduces the computational complexity, and enhances the network’s ability to extract multi-scale object features. It adapts to the complex background and small object characteristics of a large-scene remote sensing image. In AD-FCN, the object mask and object orientation estimation layer are designed to achieve fine positioning of candidate frames. The performance of the proposed algorithm is compared with that of other advanced methods on NWPU_VHR-10, DOTA, UCAS-AOD, and other open datasets. The experimental results show that the proposed algorithm significantly improves the efficiency of object detection while ensuring detection accuracy and has high adaptability. It has extensive engineering application prospects.
Airborne LiDAR Point Cloud Filtering by a Multilevel Adaptive Filter Based on Morphological Reconstruction and Thin Plate Spline Interpolation
Authors: Meng Xiangshuang , Lin Yi , Yan Lei , Gao Xianlian , Yao Yunjun , Wang Cheng , Luo Shezhou
Published: October 2019

Point cloud filtering is a crucial step in most airborne light detection and ranging (LiDAR) applications. Many filtering algorithms have been proposed, but the filtering effect has some limitations in complex environments. To improve the filtering effect in complex terrain, a multilevel adaptive filter (MAF) combining morphological reconstruction and thin plate spline (TPS) interpolation is proposed. The digital elevation model (DEM) generated in each iteration is used as the marker image for morphological reconstruction to extract ground pixels, and an adaptive residual threshold is achieved by using terrain gradient as a compensation. The benchmark dataset provided by the International Society for Photogrammetry and Remote Sensing (ISPRS) and another LiDAR dataset in northwestern China were used to evaluate the filtering performance of MAF. For the ISPRS benchmark dataset, MAF obtained the lowest average total error (3.72%) and highest average kappa coefficient (87.16%) compared with eight classic filtering algorithms. For the dataset in northwestern China, the DEM generated from the filtering result of MAF obtained higher accuracy than the filtering result of TerraScan. Overall, the MAF achieved promising results without considering the selection of filtering window, which may enhance the robustness and applicability of the algorithm in different environments.
Management of Multiple-Transmitter Multiple-Receiver Wireless Power Transfer Systems Using Improved Current Distribution Control Strategy
Authors: Cai Weikun , Lai Xiaoyang , Ma Dianguang , Tang Houjun , Hashmi Khurram , Xu Junzhong
Published: October 2019

For high-power single-transmitter single-receiver wireless power transfer (STSRWPT) systems, the coils suffer from high voltage and current stresses. With increased power requirements, the coils become bottlenecks for power flow. To increase the power level, multiple-transmitter multiple-receiver wireless power transfer (MTMRWPT) systems with parallel circuits are developed that reduce the voltage and current stresses on the coils and improve power-handling capability. Firstly, an improved current distribution (ICD) control strategy is developed to simultaneously achieve high transfer efficiency, balanced current distribution and constant output voltage. Secondly, it is further shown that the ICD control strategy has the advantage that the currents at the transmitter coils are balanced and it reduces the control complexity simultaneously. Thirdly, an asynchronous particle swarm optimization (APSO) algorithm is applied to the ICD control strategy to verify the feasibility of the proposed control strategy. Lastly, a two-transmitter two-receiver wireless power transfer (WPT) system based on the ICD control strategy is proved to obtain an efficiency of more than 89.1% and provides the target output voltage 20 V with balanced current distribution.
Building Scalable and Secure Multicast Delivery Infrastructure in a Local Area Network
Authors: Veeraraghavan Prakash , Hanna Dalal , Pardede Eric
Published: October 2019

Internet Protocol (IP) multicasting is a method for one-to-many and many-to-many communication between hosts in an IP network. This communication happens in a real-time synchronous fashion. It is a useful mechanism for distributing management data in a Local Area Network (LAN). Management data includes frequent updating of host Operating System (OS), security patches, OS update for network hardware, new configuration updates, etc. In the absence of any admission control or a source identification, any host with malicious intent can disseminate malicious codes or rootkits exploiting the underlying multicast framework. Routing protocols like RIPv2 and OSPF use a certain form of authentication to exchange routing information with their peer routers. However, their authentication and the distribution of routing information in its present form has several security and performance-related issues. Motivated through these problems, in this paper, we propose an efficient and scalable multicast architecture for distributing management and routing information in a LAN. We use Core-based Tree (CBT) for constructing the multicast delivery tree and the pseudo identity-based encryption of the underlying cryptosystem. We also demonstrate that our proposed multicast architecture is immune to a number of popular attacks.
Experimental Study of Crack Propagation in Cracked Concrete
Authors: Wang Siyao , Hu Shaowei
Published: October 2019

The intersection of cracks has an important role in the key technology of hydraulic fracturing for enhancing the recovery of tight hydrocarbon reservoirs. On the basis of digital image correlation technology, three-point bending tests of concrete beams with an edge crack and a central preset crack were conducted to investigate the propagation of cracks after intersection in concretes. Concrete beams with cracks of different positions, lengths, and approach angles were tested, and results were analyzed. In conclusion, the crack positions, crack lengths, and approach angles significantly influence the crack propagation in naturally cracked concrete. A large distance between the crack tip and central point at the preset transverse crack and crack length indicate a high possibility of the edge crack vertically crossing the preset crack. In particular, the crack restarts from the preset crack tip after intersection when the distance between two cracks is smaller than 30 mm and when the preset crack length is smaller than 40 mm. A large approach angle corresponds to a large carrying capacity of the beam and a high possibility of the crack propagating perpendicularly. An improved criterion of restart cracking after interaction is proposed, and the restart points of all tested beams are predicted and compared with the experimental results. A good agreement is observed, which proves that this criterion is reliable.
An Experimental Study on the Performance and Emission of the diesel/CNG Dual-Fuel Combustion Mode in a Stationary CI Engine
Authors: Jamrozik Arkadiusz , Tutak Wojciech , Grab-Rogaliński Karol
Published: October 2019

One of the possibilities to reduce diesel fuel consumption and at the same time reduce the emission of diesel engines, is the use of alternative gaseous fuels, so far most commonly used to power spark ignition engines. The presented work concerns experimental research of a dual-fuel compression-ignition (CI) engine in which diesel fuel was co-combusted with CNG (compressed natural gas). The energy share of CNG gas was varied from 0% to 95%. The study showed that increasing the share of CNG co-combusted with diesel in the CI engine increases the ignition delay of the combustible mixture and shortens the overall duration of combustion. For CNG gas shares from 0% to 45%, due to the intensification of the combustion process, it causes an increase in the maximum pressure in the cylinder, an increase in the rate of heat release and an increase in pressure rise rate. The most stable operation, similar to a conventional engine, was characterized by a diesel co-combustion engine with 30% and 45% shares of CNG gas. Increasing the CNG share from 0% to 90% increases the nitric oxide emissions of a dual-fuel engine. Compared to diesel fuel supply, co-combustion of this fuel with 30% and 45% CNG energy shares contributes to the reduction of hydrocarbon (HC) emissions, which increases after exceeding these values. Increasing the share of CNG gas co-combusted with diesel fuel, compared to the combustion of diesel fuel, reduces carbon dioxide emissions, and almost completely reduces carbon monoxide in the exhaust gas of a dual-fuel engine.
Smart Battery Pack for Electric Vehicles Based on Active Balancing with Wireless Communication Feedback
Authors: Ricco Mattia , Meng Jinhao , Gherman Tudor , Grandi Gabriele , Teodorescu Remus
Published: October 2019

In this paper, the concept of smart battery pack is introduced. The smart battery pack is based on wireless feedback from individual battery cells and is capable to be applied to electric vehicle applications. The proposed solution increases the usable capacity and prolongs the life cycle of the batteries by directly integrating the battery management system in the battery pack. The battery cells are connected through half-bridge chopper circuits, which allow either the insertion or the bypass of a single cell depending on the current states of charge. This consequently leads to the balancing of the whole pack during both the typical charging and discharging time of an electric vehicle and enables the fault-tolerant operation of the pack. A wireless feedback for implementing the balancing method is proposed. This solution reduces the need for cabling and simplifies the assembling of the battery pack, making also possible a direct off-board diagnosis. The paper validates the proposed smart battery pack and the wireless feedback through simulations and experimental results by adopting a battery cell emulator.
Active and Reactive Power Control of a PV Generator for Grid Code Compliance
Authors: Cabrera-Tobar Ana , Bullich-Massagué Eduard , Aragüés-Peñalba Mònica , Gomis-Bellmunt Oriol
Published: October 2019

As new grid codes have been created to permit the integration of large scale photovoltaic power plants into the transmission system, the enhancement of the local control of the photovoltaic (PV) generators is necessary. Thus, the objective of this paper is to present a local controller of active and reactive power to comply the new requirements asked by the transmission system operators despite the variation of ambient conditions without using extra devices. For this purpose, the control considers the instantaneous capability curves of the PV generator which vary due to the change of solar irradiance, temperature, dc voltage and modulation index. To validate the control, the PV generator is modeled in DIgSILENT PowerFactory ® and tested under different ambient conditions. The results show that the control developed can modify the active and reactive power delivered to the desired value at different solar irradiance and temperature.
Feasibility Analysis and Performance Evaluation and Optimization of a DXSAHP Water Heater Based on the Thermal Capacity of the System: A Case Study
Authors: De León-Ruiz Jorge E. , Carvajal-Mariscal Ignacio , Ponsich Antonin
Published: October 2019

The present work conducts an evaluation of the feasibility and the overall performance and consequent optimization of a direct expansion solar assisted heat pump (DXSAHP) employed for domestic water heating. For the study conducted R134a, R404A, R407C and R410A working fluids were evaluated as well as the use of four, six and eight flat-plate solar collectors and a worktime ranging from 1 to 6 h. The case study is based in Mexico City with a 300 L container and a hot water outlet temperature of 51 °C. The paper introduces a new evaluation criterion based on the thermal capacity and all the evaluations conducted throughout this research revolve around this performance metric. The results show that, the system would require at least 4 h of operation to achieve the outlet temperature. Additionally, it was found that the R410A refrigerant has the best heat transfer properties; with an average condensation heat rate of 6.31 kW, followed by the R407C with 5.72 kW, the R404A with 5.42 kW and the R134a with 5.18 kW. Diversely, the R134a refrigerant requires 0.402 kW of compression work, 62% less than the R410A, which requires 1.06 kW. Consequently, R134a delivers the highest COP, which ranges from 7 to 14, followed by the R407C and R404A refrigerants, which present a similar behaviour between them, with COP ranging from 5 to 9 and 4 to 8, respectively, and finally the R410A, achieving the lowest COP, ranging from 3.5 to 6.5. Moreover, it was found that the R134a presents a higher dispersion regarding the energy exchange rate, which reveals that it is the fluid most susceptible to external factors, such as the weather. Contrarily, the remaining refrigerants present a more consistent performance. Finally, the optimization revealed that the R407C refrigerant is the most suitable given that it requires 20% less compression work than the R404A. This provides the heat pump system with a steadier behaviour, a COP ranging from 7 to 8, 30% higher than R410A, a worktime decrease of 1.5 h and heat transfer area of 5.5 flat-plate solar collectors, equivalent to a 31% reduction, both compared to R134a.
Blockchain Technology for Intelligent Environments
Authors: Voulgaris Spyros , Fotiou Nikos , Siris Vasilios A. , Polyzos George C. , Jaatinen Mikael , Oikonomidis Yannis
Published: October 2019

In the last few years, we have been witnessing the convergence of the physical with the digital world. The Internet of Things (IoT) is progressing at a fast pace, and IoT devices are becoming pervasive in our physical environments, bringing the vision of Intelligent Environments closer to reality. At the same time, the newly-introduced blockchain technology is offering for the first time ever cryptographically proven trust based on a set of mutually untrusted nodes. Blockchain technology thus has the potential to become a key component of many IoT systems, offering them an unprecedented level of accountability, transparency, and reliability. This paper first lays out the principles on which blockchain systems are operating, along with descriptions of the most noteworthy blockchain implementations. It then presents a number of systems through which blockchains may interact with external systems and third-party data sources. Finally, it provides a survey of the state-of-the-art blockchain-based systems targeting IoT applications.
Effect of Cyclic Damage on the Performance of RC Square Columns Strengthened Using Hybrid FRP Composites under Axial Compression
Authors: Chellapandian M. , Jain Saumitra , Suriya Prakash S. , Sharma Akanshu
Published: October 2019

The effectiveness of hybrid fibre-reinforced polymer (FRP) strengthening is evaluated for rapid repair of the pre-damaged plain concrete (PC) and reinforced concrete (RC) columns. The objective of this study is to understand the efficiency of hybrid technique for completely restoring the initial stiffness, load carrying capacity and ductility of pre-damaged columns under cyclic compression loads. Two series of PC and RC square columns were cast. The columns were pre-damaged by loading up to 80% of peak load capacity for three cycles under pure compression. After cyclic damage, the columns were strengthened with two techniques, namely (a) near-surface mounted (NSM) carbon FRP (CFRP) laminates and (b) hybrid FRP technique, which uses a combination of NSM and externally bonded (EB) CFRP fabric. Analytical modelling was carried out for predicting the behaviour of columns with initial cyclic pre-damage. Additionally, a phased three-dimensional nonlinear finite element (FE) analysis was performed to validate the behaviour of pre-damaged columns with different strengthening techniques. Test results show that cyclic pre-loading and resulting damage causes a reduction in axial stiffness of all damaged specimens. Hybrid strengthening completely restored the stiffness and strength under compression. Prediction of analytical and FE analysis correlated well with the tests.
Antioxidant and Mineral Composition of Three Wild Leafy Species: A Comparison Between Microgreens and Baby Greens
Authors: Lenzi Anna , Orlandini Alessandro , Bulgari Roberta , Ferrante Antonio , Bruschi Piero
Published: October 2019

Wild plants may play an important role in human nutrition and health and, among them, many are the leafy species. We hypothesized that the wild greens could be profitably grown as microgreens and baby greens, specialty products whose market is increasing. We compared three wild leafy species (Sanguisorba minor Scop., Sinapis arvensis L., and Taraxacum officinale Weber ex F. H. Wigg.) harvested at the microgreen and baby green stages. Seedlings were grown hydroponically in a half-strength Hoagland nutrient solution under controlled climatic conditions. At harvest, the yield was assessed, and chlorophylls, carotenoids, anthocyanins, phenolic index, nitrate, and mineral elements were measured in the two types of product. The potential contribution to human mineral intake was calculated, and the possible risk due to the presence of metals potentially detrimental for health was estimated. Results showed that micro/baby greens of the studied wild plants achieved competitive yields and could contribute to the dietary intake of macroelements, microelements, and non-nutrient bioactive compounds. On the other hand, the wild greens showed high amounts of nitrate and traces of some metals potentially detrimental for health, suggesting the need for caution in the use of wild species for producing microgreens and baby leaves.
Liberation and Micellarization of Carotenoids from Different Smoothies after Thermal and Ultrasound Treatments
Authors: Buniowska Magdalena , Arrigoni Eva , Znamirowska Agata , Blesa Jesús , Frígola Ana , Esteve María J.
Published: October 2019

The consumption of a varied diet rich in fruit and vegetables helps prevent and treat certain chronic diseases. The development of smoothies based on derivatives from fruit and vegetables rich in bioactive compounds can help increase the consumption of these foods, and therefore, contribute to the prevention of various health problems. However, during the processing of the fruit and vegetable smoothies, these properties may change. The elaboration of smoothies is based on fruits and vegetables rich in carotenoids: Carrot juice-papaya-mango (smoothie A) and carrot juice-pumpkin-mango (smoothie B). The objective of this study is to evaluate the impact of the application of different thermal technologies (mild and intensive heat treatment) and non-conventional technologies (ultrasound) on carotenoids (α-carotene, β-carotene, lutein and β-cryptoxantin) and determine the physiochemical parameters of derivatives from fruit and vegetable smoothies. In addition, the bioaccessibility of carotenoids is also evaluated through a process of in vitro simulated digestion. With regard to the bioaccessibility of the fruit and vegetable smoothies analyzed, a positive effect of temperature on liberation and micellarization was observed.
Edible Leafy Vegetables from West Africa (Guinea-Bissau): Consumption, Trade and Food Potential
Authors: Catarino Luís , Romeiras Maria M. , Bancessi Quintino , Duarte Daniel , Faria Diana , Monteiro Filipa , Moldão Margarida
Published: October 2019

Wild Edible Plants are common in the diet of rural communities of sub-Saharan Africa. In Guinea-Bissau, West Africa, wild plant resources are widely used in human diet, but very few studies have addressed them. The aim of this study is to reveal: (1) the wild and semi-cultivated leafy vegetables consumed in Guinea-Bissau; and (2) the nutritional composition of those plants traded at the largest country market in Bissau. Our results revealed that 24 native or naturalized species with edible leaves are currently consumed by Guinea-Bissau population. Five of them were found at the market: dried leaves of Adansonia digitata, Bombax costatum and Sesamum radiatum, and fresh leaves and shoots of Amaranthus hybridus and Hibiscus sabdariffa. The analysis of the nutritional properties revealed that leaves contain a significant amount of protein (10.1–21.0 g/100 g, dry basis), high values of macronutrients and micronutrients, as well as of phenolic compounds (13.1–40.3 mg GAE/g) and a considerable antioxidant capacity (DPPH 111.5–681.9 mg Eq Trolox). Although price and availability vary among the leafy vegetables analyzed, these traditional foods appear to be a good dietary component that can contribute to food security in Guinea-Bissau and in other West African countries, as these species are widely distributed in this region.
Rice-Buckwheat Gluten-Free Pasta: Effect of Processing Parameters on Quality Characteristics and Optimization of Extrusion-Cooking Process
Authors: Bouasla Abdallah , Wójtowicz Agnieszka
Published: October 2019

A new type of gluten-free pasta has been developed based on a rice-buckwheat mixture. The aim of the study was to investigate the effect of process parameters of moisture content (30, 33, and 36%), barrel temperature (80, 100, and 120 °C), and screw speed (60, 80, and 100 rpm) on cooking and textural properties of rice-buckwheat pasta produced by a single-screw extrusion-cooker. The process uses response surface methodology based on a Box-Behnken experimental design. Results showed that with regard to this rice-buckwheat pasta, raising moisture content of the raw materials increased cooking loss and stickiness, but decreased firmness, while increasing barrel temperature reduced cooking loss and stickiness, but increased hardness and firmness. Screw speed increase also affected positively hardness and firmness of the obtained products. Thus, optimal conditions (moisture content 30%, barrel temperature 120 °C, and screw speed 80 rpm) were established to produce good quality rice-buckwheat pasta. At this optimum, the pasta showed a compact and homogeneous inside microstructure. Furthermore, the pasta products exhibited low cooking loss (less than 6%), good hardness and firmness, with low stickiness and acceptable scores for all sensory attributes and for overall quality.
Broken by the Cut: A Journey into the Role of Topoisomerase II in DNA Fragility
Authors: Atkin Naomi , Raimer Heather , Wang Yuh-Hwa
Published: October 2019

DNA topoisomerase II (TOP2) plays a critical role in many processes such as replication and transcription, where it resolves DNA structures and relieves torsional stress. Recent evidence demonstrated the association of TOP2 with topologically associated domains (TAD) boundaries and CCCTC-binding factor (CTCF) binding sites. At these sites, TOP2 promotes interactions between enhancers and gene promoters, and relieves torsional stress that accumulates at these physical barriers. Interestingly, in executing its enzymatic function, TOP2 contributes to DNA fragility through re-ligation failure, which results in persistent DNA breaks when unrepaired or illegitimately repaired. Here, we discuss the biological processes for which TOP2 is required and the steps at which it can introduce DNA breaks. We describe the repair processes that follow removal of TOP2 adducts and the resultant broken DNA ends, and present how these processes can contribute to disease-associated mutations. Furthermore, we examine the involvement of TOP2-induced breaks in the formation of oncogenic translocations of leukemia and papillary thyroid cancer, as well as the role of TOP2 and proteins which repair TOP2 adducts in other diseases. The participation of TOP2 in generating persistent DNA breaks and leading to diseases such as cancer, could have an impact on disease treatment and prevention.
Identification of Long Non-Coding RNA-Associated Competing Endogenous RNA Network in the Differentiation of Chicken Preadipocytes
Authors: Chen Lan , Zhang Tao , Zhang Shanshan , Huang Jinxing , Zhang Genxi , Xie Kaizhou , Wang Jinyu , Wu Haiqing , Dai Guojun
Published: October 2019

Emerging evidence indicates that long noncoding RNAs (lncRNAs) play important roles in the regulation of cell differentiation by acting as competing endogenous RNA (ceRNA). However, the regulatory mechanisms of lncRNA and the lncRNA-associated ceRNA network involved in adipogenic differentiation of chicken preadipocytes remain elusive. Here, we first constructed the chicken preadipocyte in vitro induction model. Then, we identified differentially expressed lncRNAs (DELs), miRNAs (DEMis), and mRNAs (DEMs) between differentiated and undifferentiated preadipocytes. Furthermore, we constructed the lncRNA associated ceRNA network by gene expression correlation analysis and target prediction of DELs, DEMis, and DEMs. Finally, we determined twelve candidate lncRNA-miRNA-mRNA interactions from the lncRNA associated ceRNA network. Eight out of the twelve interactions were validated by RT-qPCR, indicating their potential role in the regulation of chicken preadipocytes differentiation. Among the eight interactions, TCONS_00026544-gga-miR-128-1-5p-RASD1, TCONS_00055280-gga-miR-135a-5p-JAM3, TCONS_00055280-gga-miR-135a-5p-GPR133, TCONS_00055280-gga-miR-135a-5p-CLDN1, and TCONS_00055280-gga-miR-135a-5p-TMEM123 may promote adipogenic differentiation of chicken preadipocytes while TCONS_00057272-gga-miR-146a-3p-FOXO6, TCONS_00057242-gga-miR-6615-3p-FOXO6, and TCONS_00057242-gga-miR-6615-3p-ENSGALT00000043224 have the opposite effects. Our results not only provide novel insights into ceRNA roles of lncRNAs in chicken preadipocytes differentiation and but also contribute to a better understanding of chicken fat deposition.
Characterization of GLOD4 in Leydig Cells of Tibetan Sheep during Different Stages of Maturity
Authors: Wang Xia , Li Taotao , Liu Ningbo , Zhang Hongyu , Zhao Xingxu , Ma Youji
Published: October 2019

We have previously reported that glyoxalase domain-containing protein 4 (GLOD4) is expressed in sheep testes by proteome analysis, but its roles during testicular development remain unclear. The aim of this study was to understand the expression characteristics and biological functions of the GLOD4 gene in developmental Tibetan sheep testes. The cDNA sequence of the Tibetan sheep GLOD4 gene was cloned by the RT-PCR method, and the structural characteristics of the GLOD4 protein were analyzed using relevant bioinformatics software, including ProtParam, TMHMM, Signal P 4.1, SOPMA, and phyre2. The expression patterns and immunolocalization of GLOD4 were examined in developmental testes derived from three-month-old (3M), one-year-old (1Y), and three-year-old (3Y) Tibetan sheep using quantitative real-time PCR (qRT-PCR), Western blot, immunohistochemistry, and immunofluorescence staining. The sequence analysis showed that the coding sequence (CDS) region of the GLOD4 gene was 729 bp in length and encoded 242 amino acids. Bioinformatics analysis found that the nucleotide and amino acid sequence of Tibetan sheep GLOD4 exhibited the highest sequence similarity with goat and chiru, and the least with zig-zag eel, of the species compared. GLOD4 expressions at both the mRNA and protein levels were significantly higher in the testes of the 1Y and 3Y groups than those in the 3M group (p < 0.01). Immunohistochemistry and immunofluorescence results indicated that the GLOD4 protein was mainly localized in the cytoplasm of Leydig cells from Tibetan sheep testes throughout the development stages. These results taken together suggest that the GLOD4 gene may be implicated in the development of the Leydig cells of Tibetan sheep during different stages of maturity.
Pollination Drop Proteome and Reproductive Organ Transcriptome Comparison in Gnetum Reveals Entomophilous Adaptation
Authors: Hou Chen , Saunders Richard M. K. , Deng Nan , Wan Tao , Su Yingjuan
Published: October 2019

Gnetum possesses morphologically bisexual but functionally unisexual reproductive structures that exude sugary pollination drops to attract insects. Previous studies have revealed that the arborescent species (G. gnemon L.) and the lianoid species (G. luofuense C.Y.Cheng) possess different pollination syndromes. This study compared the proteome in the pollination drops of these two species using label-free quantitative techniques. The transcriptomes of fertile reproductive units (FRUs) and sterile reproductive units (SRUs) for each species were furthermore compared using Illumina Hiseq sequencing, and integrated proteomic and transcriptomic analyses were subsequently performed. Our results show that the differentially expressed proteins between FRUs and SRUs were involved in carbohydrate metabolism, the biosynthesis of amino acids and ovule defense. In addition, the differentially expressed genes between the FRUs and SRUs (e.g., MADS-box genes) were engaged in reproductive development and the formation of pollination drops. The integrated protein-transcript analyses revealed that FRUs and their exudates were relatively conservative while the SRUs and their exudates were more diverse, probably functioning as pollinator attractants. The evolution of reproductive organs appears to be synchronized with changes in the pollination drop proteome of Gnetum, suggesting that insect-pollinated adaptations are not restricted to angiosperms but also occur in gymnosperms.
Transcriptomics of Tasmanian Devil (Sarcophilus Harrisii) Ear Tissue Reveals Homogeneous Gene Expression Patterns across a Heterogeneous Landscape
Authors: Fraik Alexandra K. , Quackenbush Corey , Margres Mark J. , Comte Sebastien , Hamilton David G. , Kozakiewicz Christopher P. , Jones Menna , Hamede Rodrigo , Hohenlohe Paul A. , Storfer Andrew , Kelley Joanna L.
Published: October 2019

In an era of unprecedented global change, exploring patterns of gene expression among wild populations across their geographic range is crucial for characterizing adaptive potential. RNA-sequencing studies have successfully characterized gene expression differences among populations experiencing divergent environmental conditions in a wide variety of taxa. However, few of these studies have identified transcriptomic signatures to multivariate, environmental stimuli among populations in their natural environments. Herein, we aim to identify environmental and sex-driven patterns of gene expression in the Tasmanian devil (Sarcophilus harrisii), a critically endangered species that occupies a heterogeneous environment. We performed RNA-sequencing on ear tissue biopsies from adult male and female devils from three populations at the extremes of their geographic range. There were no transcriptome-wide patterns of differential gene expression that would be suggestive of significant, environmentally-driven transcriptomic responses. The general lack of transcriptome-wide variation in gene expression levels across the devil’s geographic range is consistent with previous studies that documented low levels of genetic variation in the species. However, genes previously implicated in local adaptation to abiotic environment in devils were enriched for differentially expressed genes. Additionally, three modules of co-expressed genes were significantly associated with either population of origin or sex.
“We are already person-centred in our practice”—A Qualitative Study of Ambulance Clinicians’ Experiences of Person-Centred Care
Authors: Rantala Andreas , Ingoldsson Anton , Persson Eva I
Published: October 2019

The concept of person-centred care (PCC) is considered one of the core competencies in Swedish healthcare. It has increasingly spread and involves treating the patient as a person who is decision-competent and part of the team. The PCC concept has been introduced in the Swedish Ambulance Service setting, but as there has been no previous research on PCC in this context, the aim of the present study was to illuminate ambulance clinicians’ experiences of the introduction of PCC in a Swedish Ambulance Service setting. Data collection took the form of interviews with 15 ambulance clinicians in the southernmost part of Sweden. Qualitative content analysis was employed to analyse the interviews, wherein two categories emerged: organisational perspective and contextual culture. The latent meaning was interpreted as the theme: Seeing the individual in need of care as a person instead of a patient. In conclusion, the concept of PCC was considered a barrier and there was some resistance to its introduction. While PCC enhanced the ambulance clinicians’ stance, e.g., when initiating a caring relationship and encouraging the patient to participate in her/his care, it was also described as a catchphrase that is not applicable to the Ambulance Service as it contributes nothing new to the standard of treatment.
Developmental Changes in the Philippine Health System: Accomplishments, Successes and Challenges
Authors: Seposo Xerxes
Published: October 2019

The Philippine health system has undergone various changes which addressed the needs of the time. These changes were reflected in the benchmarks and indicators of performance of the whole health system. To understand how these changes affected the health system (HS), this study determined the changes in the Philippine health system in relation to different health domains (health determinants, financing, and management/development). Two HS periods were identified, namely, health system period 1 (HS 1) from 1997–2007 and health system period 2 (HS 2) from 2008–2017. Each HS period was assessed based on three domains. The first two domains were quantitatively assessed based on an interrupted time-series method, while the third one underwent a comparative analysis using two Health Systems in Transition reports (2011 and 2018). This study was able to assess the developmental changes in the Philippine health system. Specifically, the (health determinant) maternal mortality rate (MMR) significantly decreased by three maternal deaths per 100,000 live births, the (health financing) tobacco excise tax increased by 13,855 (in Million PhP) in HS 2, and there was (health management/development) an improvement in access to health facilities. However, there was an indication of retrogressive progress with some challenges in HS 1 which remained unaddressed in HS 2. While it seems promising that the health system has progressed with improvements apparent in both health outcomes (e.g., MMR) and health financing (e.g., tobacco excise tax), such improvements were overshadowed by the inefficiencies, which were not addressed by the current health system (HS 2), thus making it more retrogressive than progressive.
A Case Study of Rainfall and Temperature Trends in San Diego Region, 1985–2017
Authors: Mosase Esther , Ahiablame Laurent , Light Fritz , Dwomoh Francis
Published: October 2019

Prolonged and frequent droughts in Southern California present hazards and uncertainty for the region’s increasing population, resulting in proactive and aggressive water management strategies. The goal of this study is to present a case study of the San Diego region’s rainfall and temperature time series analysis in order to determine annual and seasonal trends and their significance. Rainfall and temperature data from 20 rain-gauged stations were analyzed for the period 1985–2017. A project database was set up for data compilation and quality control, and a Mann-Kendall test for trend analysis was used. Results indicated that rainfall in the region decreased both annually and during the rainy season (November–April) by up to 0.14 mm between 1985 and 2017, although not in a statistically significant manner, except at two rainfall observation stations. Rainfall appears to have increased in many of the stations examined during the dry season (May–October), with an average magnitude of 0.09 mm. Analysis of daily minimum and maximum temperature reveals overall average annual and seasonal increases of 0.07 °C and 0.04 °C, respectively, with statistically significant increases at 10 of 17 for minimum temperature, and 0.27 °C and −0.25 °C with statistically significant increases at 9 of 16 for maximum temperature. Temperature tends to have increased more during the dry season compared to the rainy season. This study reveals an overall decreasing tendency in rainfall and an increasing tendency in minimum and maximum temperatures (although not statistically significant) in the San Diego region between 1985 and 2017, which likely contributed to important management implications for the region’s water resources.
The Temporal Variability of Rainfall and Streamflow into Lake Nakuru, Kenya, Assessed Using SWAT and Hydrometeorological Indices
Authors: Kimaru Alice Nyawira , Gathenya John Mwangi , Cheruiyot Charles K.
Published: October 2019

Temporal variability analysis of rainfall and river discharges is useful in determining the likelihood of the occurrence of extreme events such as drought or flooding for the purposes of developing policies to mitigate their effects. This study investigated the temporal variability of rainfall and discharges into Lake Nakuru, Kenya using meteorological drought indicators and hydrological drought indicators from 1981 to 2018. The standardized precipitation index (SPI) and standardized precipitation evaporation index (SPEI) were used to characterize meteorological drought, while the streamflow drought index (SDI) was used to characterize hydrological drought. A SWAT model was applied for the prediction of streamflow on five tributaries of Lake Nakuru (Njoro, Ngosur, Nderit, Larmudiac, and Makalia Rivers). The model was successfully calibrated on Njoro River at the upstream of river gauging station 2FCO5 from 1984 to 1996, and the parameters were validated from 1997 to 2007. The SUFI-2 algorithm was applied in SWATCup to perform the calibration of the model. The model performance was considered satisfactory in daily time step (NSE = 0.58, R2 = 0.58 during calibration and NSE = 0.52, R2 = 0.68 during validation). The average annual water balance revealed that out of 823 mm received annual precipitation, 154 mm was surface runoff and 178 mm was the annual average water yield. The average annual actual evapotranspiration (ET) was 607 mm. The results for the temporal variation of the SPI and SDI for the five subcatchments indicated that the drought events identified by the 12-month SPI/SPEI were almost all identified by the 12-month SDI. At the catchment scale, SPI showed an equal distribution of wet and dry periods, with 50.00% of positive anomalies and 50.00% of negative anomalies being observed from 1981 to 2018, while SDI observes a high frequency of dry periods (52.63%) and a lower frequency of wet periods (47.37%). There is a higher frequency of wet periods compared to dry periods for both indices from 2009 to 2010 at 60.00% and 40.00% for SPI and 90.00% and 10.00% for SDI, respectively. Both indices observed that 1984 and 2000 were severely dry years (SPI/SPEI < −2.00), while 2018 was severely wet (SPI/SPEI > 2.00). The results for the variability in rainfall and streamflow indices revealed that the last 10 years (2009–2018) were wetter than the period from 1981 to 2008.
Factors Associated with Meeting Current Recommendation for Physical Activity in Scottish Adults with Diabetes
Authors: Salman Ahmad , Ukwaja Kingsley Nnanna , Alkhatib Ahmad
Published: October 2019

It remains unclear which factors are instrumental in meeting the recommended physical activity in people with diabetes. We, therefore, aimed to determine the sociodemographic, health-related behavior and clinical factors associated with meeting the recommended levels of physical activity in Scottish adults with diabetes. The study was based on the nationally-representative cross-sectional Scottish Health Surveys (2014–2017). The study participants included a sub-sample of 1259 adults (≥16 years old) with diabetes. Physical activity was evaluated using international guidelines. Overall, 34.1% of the subjects met the recommended levels of physical activity. Independent determinants of meeting the recommended levels of physical activity include male gender (odds ratio (OR) 1.47; 95% confidence interval (CI) 1.07–2.00) and being a non-smoker (OR 1.62; 95% CI 1.02–2.56). Furthermore, meeting the recommended physical activity levels decreased with age (OR 0.96; 95% CI 0.95–0.97), having a longstanding illness (OR 0.56; 95% CI 0.34–0.93) and body mass index (OR 0.94; 95% CI 0.92–0.97), but increased with higher fruit and vegetable intake (OR 1.16; 95% CI 1.07–1.25) and mental wellbeing (OR 1.04; 95% CI 1.02–1.06). Implementation of health promotion programs that target the identified determinants is needed to improve the recommended levels of physical activity among adults with diabetes.