bluuebunny/crossref_metadata_2025 huggingface dataset:
Characteristics of Welding and Arc Pressure in the Plasma–TIG Coupled Arc Welding Process
Authors: Wang Bo , Zhu Xun-Ming , Zhang Hong-Chang , Zhang Hong-Tao , Feng Ji-Cai
Published: July 2018

In this article, a novel hybrid welding process called plasma-TIG (Tungsten Inert Gas welding) coupled arc welding was proposed to improve the efficiency and quality of welding by utilizing the full advantage of plasma and TIG welding processes. The two arcs of plasma and TIG were pulled into each other into one coupled arc under the effect of Lorentz force and plasma flow force during welding experiments. The arc behavior of coupled arc was studied by means of its arc profile, arc pressure and arc force conditions. The coupled arc pressure distribution measurements were performed. The effects of welding conditions on coupled arc pressure were evaluated and the maximum coupled arc pressure was improved compared with single-plasma arc and single-TIG arc. It was found that the maximum arc pressure was mainly determined by plasma arc current and plasma gas flow. Compared with traditional hybrid welding method, the efficiency was obviously higher and the welding heat-input was lower. The epitaxial solidification of the weld was inhibited, the tensile strength of the welded joints was higher. According to the results, the proposed coupled arc welding process has both advantages of plasma arc and TIG method, and it has a broad application prospect.
Characterization of Small Molecules Inhibiting the Pro-Angiogenic Activity of the Zinc Finger Transcription Factor Vezf1
Authors: He Ming , Yang Qianyi , Norvil Allison B. , Sherris David , Gowher Humaira
Published: July 2018

Discovery of inhibitors for endothelial-related transcription factors can contribute to the development of anti-angiogenic therapies that treat various diseases, including cancer. The role of transcription factor Vezf1 in vascular development and regulation of angiogenesis has been defined by several earlier studies. Through construction of a computational model for Vezf1, work here has identified a novel small molecule drug capable of inhibiting Vezf1 from binding to its cognate DNA binding site. Using structure-based design and virtual screening of the NCI Diversity Compound Library, 12 shortlisted compounds were tested for their ability to interfere with the binding of Vezf1 to DNA using electrophoretic gel mobility shift assays. We identified one compound, T4, which has an IC50 of 20 μM. Using murine endothelial cells, MSS31, we tested the effect of T4 on endothelial cell viability and angiogenesis by using tube formation assay. Our data show that addition of T4 in cell culture medium does not affect cell viability at concentrations lower or equal to its IC 50 but strongly inhibits the network formation by MSS31 in the tube formation assays. Given its potential efficacy, this inhibitor has significant therapeutic potential in several human diseases.
Rapid Determination of Saponins in the Honey-Fried Processing of Rhizoma Cimicifugae by Near Infrared Diffuse Reflectance Spectroscopy
Authors: Wu Lun , Su Yang , Yu Haoran , Qian Xiuhui , Zhang Xueting , Wang Qiuhong , Kuang Haixue , Cheng Genhong
Published: July 2018

Objective: A model of Near Infrared Diffuse Reflectance Spectroscopy (NIR-DRS) was established for the first time to determine the content of Shengmaxinside I in the honey-fried processing of Rhizoma Cimicifugae. Methods: Shengmaxinside I content was determined by high-performance liquid chromatography (HPLC), and the data of the honey-fried processing of Rhizoma Cimicifugae samples from different batches of different origins by NIR-DRS were collected by TQ Analyst 8.0. Partial Least Squares (PLS) analysis was used to establish a near-infrared quantitative model. Results: The determination coefficient R2 was 0.9878. The Cross-Validation Root Mean Square Error (RMSECV) was 0.0193%, validating the model with a validation set. The Root Mean Square Error of Prediction (RMSEP) was 0.1064%. The ratio of the standard deviation for the validation samples to the standard error of prediction (RPD) was 5.5130. Conclusion: This method is convenient and efficient, and the experimentally established model has good prediction ability, and can be used for the rapid determination of Shengmaxinside I content in the honey-fried processing of Rhizoma Cimicifugae.
Risk of Metabolic Syndrome among Middle-Aged Koreans from Rural and Urban Areas
Authors: Lee Seohyun , Shin Yoonjin , Kim Yangha
Published: July 2018

Metabolic syndrome (MetS) is a common global health problem. This study aims to assess nutrient intake and risk of MetS in middle-aged Koreans based in residential areas. Participants were 161,326 (142,137 in urban and 19,189 in rural) subjects enrolled in the Korea Genome and Epidemiology Study. The prevalence of MetS was much higher in rural (39.8%) than that in urban (22.5%) subjects (p < 0.001). The rural residents showed significantly higher blood pressure (p < 0.001), serum triglyceride levels (p < 0.001), and LDL (Low density lipoprotein)-cholesterol level (p < 0.001), as well as the odds ratio (OR) for MetS (OR = 1.65, 95% CI: 1.59–1.71), compared to urban residents. The rural subjects showed a higher consumption of carbohydrate and sodium compared to the urban subjects (p < 0.001). After adjusting for potential confounders, subjects in the highest quartile of carbohydrate intake had higher OR for MetS (OR = 1.23, 95% CI: 1.15–1.32) and those in the highest quartile of sodium intake had a higher chance of having MetS (OR = 1.11, 95% CI: 1.07–1.16) than did those in the lowest quartiles. Our results suggested that the higher consumption of carbohydrate and sodium in rural residents might be associated with the increased risk of MetS in this population.
Protective Effects of a Lipid Extract from Hard-Shelled Mussel (Mytilus coruscus) on Intestinal Integrity after Lipopolysaccharide Challenge in Mice
Authors: Wan Yi , Fu Yuanqing , Wang Fenglei , Sinclair Andrew J. , Li Duo
Published: July 2018

This study investigated the protective effects of a lipid extract from hard-shelled mussel (HMLE) on intestinal integrity and the underlying mechanisms after a lipopolysaccharide (LPS) challenge in mice by using a 3 × 2 factorial design. Mice received olive oil, fish oil, and HMLE (n = 12 per group) by using gastric gavage for six weeks, respectively. Then half the mice in each group was injected intraperitoneally with LPS and the other half with phosphate buffered saline. Four hours after injection, mice were sacrificed and samples were collected. n-3 PUFAs were significantly enriched in erythrocytes following fish oil and HMLE supplementation. Both fish oil and HMLE improved intestinal morphology by restoring the ileac villus height and barrier function, which is indicated by decreased colonic myeloperoxidase activity and increased diamine oxidase activity as well as enhanced mRNA expression of intestinal tight junction proteins known as occludin and claudin-1 when compared with olive oil. In addition, both fish oil and HMLE increased colon production and the expression of anti-inflammatory cytokine, IL-10, while they inhibited the abnormal production and expression of pro-inflammatory cytokines including TNF-α, IL-1β, and IL-6 relative to the olive oil. Lastly, in comparison with olive oil, both fish oil and HMLE downregulated the TLR-4 signaling pathway by reducing the expression of two key molecules in this pathway, which are called TLR-4 and MyD88. These results suggest that HMLE had a protective effect on intestinal integrity after the LPS challenge, which was equivalent to that of fish oil. This effect might be associated with the regulation of inflammatory mediators and the inhibition of the TLR-4 signaling pathway.
Buspirone Nanovesicular Nasal System for Non-Hormonal Hot Flushes Treatment
Authors: Touitou Elka , Natsheh Hiba , Duchi Shaher
Published: July 2018

The aim of this work was to design and characterize a new nanovesicular nasal delivery system (NDS) containing buspirone, and investigate its efficiency in an animal model for the treatment of hot flushes. The presence of multilamellar vesicles with a mean size distribution of 370 nm was evidenced by transition electron microscopy (TEM), cryo-scanning electron microscopy (Cryo-SEM), and dynamic light scattering (DLS) tests. Pharmacodynamic evaluation of the nasal treatment efficacy with the new system was carried out in ovariectomized (OVX) rat—an animal model for hot flushes—and compared with other treatments. We found that the nasal administration of a buspirone NDS resulted in a significant reduction in tail skin temperature (TST). This effect was not observed in the control buspirone-treated groups. Buspirone levels in the plasma and brain of nasally-treated normal rats were quantified and compared with those of rats that had received oral administration by a LC-MS/MS assay. A significantly higher bioavailability was achieved with the new treatment relative to an oral administration of the same drug dose. No pathological changes in the nasal cavity were observed following sub-chronic nasal administration of buspirone NDS. In conclusion, the data of our investigation show that buspirone in the new nanovesicular nasal carrier could be considered for further studies for the development of a treatment for the hot flushes ailment.
Double Reweighted Sparse Regression and Graph Regularization for Hyperspectral Unmixing
Authors: Wang Si , Huang Ting-Zhu , Zhao Xi-Le , Liu Gang , Cheng Yougan
Published: July 2018

Hyperspectral unmixing, aiming to estimate the fractional abundances of pure spectral signatures in each mixed pixel, has attracted considerable attention in analyzing hyperspectral images. Plenty of sparse unmixing methods have been proposed in the literature that achieved promising performance. However, many of these methods overlook the latent geometrical structure of the hyperspectral data which limit their performance to some extent. To address this issue, a double reweighted sparse and graph regularized unmixing method is proposed in this paper. Specifically, a graph regularizer is employed to capture the correlation information between abundance vectors, which makes use of the property that similar pixels in a spectral neighborhood have higher probability to share similar abundances. In this way, the latent geometrical structure of the hyperspectral data can be transferred to the abundance space. In addition, a double weighted sparse regularizer is used to enhance the sparsity of endmembers and the fractional abundance maps, where one weight is introduced to promote the sparsity of endmembers as a hyperspectral image typically contains fewer endmembers compared to the overcomplete spectral library and the other weight is exploited to improve the sparsity of the abundance matrix. The weights of the double weighted sparse regularizer used for the next iteration are adaptively computed from the current abundance matrix. The experimental results on synthetic and real hyperspectral data demonstrate the superiority of our method compared with some state-of-the-art approaches.
Millimeter-Wave InSAR Image Reconstruction Approach by Total Variation Regularized Matrix Completion
Authors: Zhang Yilong , Miao Wei , Lin Zhenhui , Gao Hao , Shi Shengcai
Published: July 2018

Millimeter-wave interferometric synthetic aperture radiometer (InSAR) can provide high-resolution observations for many applications by using small antennas to achieve very large synthetic aperture. However, reconstruction of a millimeter-wave InSAR image has been proven to be an ill-posed inverse problem that degrades the performance of InSAR imaging. In this paper, a novel millimeter-wave InSAR image reconstruction approach, referred to as InSAR-TVMC, by total variation (TV) regularized matrix completion (MC) in two-dimensional data space, is proposed. Based on the a priori knowledge that natural millimeter-wave images statistically hold the low-rank property, the proposed approach represents the object images as low-rank matrices and formulates the data acquisition of InSAR in two-dimensional data space directly to undersample visibility function samples. Subsequently, using the undersampled visibility function samples, the optimal solution of the InSAR image reconstruction problem is obtained by simultaneously adopting MC techniques and TV regularization. Experimental results on simulated and real millimeter-wave InSAR image data demonstrate the effectiveness and the significant improvement of the reconstruction performance of the proposed InSAR-TVMC approach over conventional and one-dimensional sparse InSAR image reconstruction approaches.
Wireless Passive Ultra High Frequency RFID Antenna Sensor for Surface Crack Monitoring and Quantitative Analysis
Authors: Zhang Jun , Huang Bei , Zhang Gary , Tian Gui Yun
Published: July 2018

An exponential increase in large-scale infrastructure facilitates the development of wireless passive sensors for permanent installation and in-service health monitoring. Due to their wireless, passive and cost-effective characteristics, ultra-high frequency (UHF) radio frequency identification (RFID) tag antenna based sensors are receiving increasing attention for structural health monitoring (SHM). This paper uses a circular patch antenna sensor with an open rectangular window for crack monitoring. The sensing mechanism is quantitatively studied in conjunction with a mode analysis, which can uncover the intrinsic principle for turning an antenna into a crack sensor. The robustness of the feature is examined when the variation of crack position associated with an aluminum sample and the antenna sensor is considered. The experimental results demonstrate a reasonable sensitivity and resolution for crack characterization.
A 10-Bit 300 kS/s Reference-Voltage Regulator Free SAR ADC for Wireless-Powered Implantable Medical Devices
Authors: Yang Yongkui , Zhou Jun , Liu Xin , Goh Wang Ling
Published: July 2018

This paper presents a reference-voltage regulator free successive-approximation-register analog-to-digital converters (SAR ADC) with self-timed pre-charging for wireless-powered implantable medical devices. Assisted by a self-timed pre-charging technique, the proposed SAR ADC eliminates the need for a power-hungry reference-voltage regulator and area-consuming decoupling capacitor while maintaining insensitivity to the supply voltage fluctuation. Fabricated with a 0.18-µm complementary metal–oxide–semiconductor (CMOS) technology, the proposed SAR ADC achieves a Signal To Noise And Distortion Ratio (SNDR) of 53.32 dB operating at 0.8 V with a supply voltage fluctuation of 50 mVpp and consumes a total power of 2.72 µW at a sampling rate of 300 kS/s. Including the self-timed pre-charging circuits, the total figure-of-merit (FOM) is 23.9 fJ/conversion-step and the total area occupied is 0.105 mm2.
Optimal Polygon Decomposition for UAV Survey Coverage Path Planning in Wind
Authors: Coombes Matthew , Fletcher Tom , Chen Wen-Hua , Liu Cunjia
Published: July 2018

In this paper, a new method for planning coverage paths for fixed-wing Unmanned Aerial Vehicle (UAV) aerial surveys is proposed. Instead of the more generic coverage path planning techniques presented in previous literature, this method specifically concentrates on decreasing flight time of fixed-wing aircraft surveys. This is achieved threefold: by the addition of wind to the survey flight time model, accounting for the fact fixed-wing aircraft are not constrained to flight within the polygon of the region of interest, and an intelligent method for decomposing the region into convex polygons conducive to quick flight times. It is shown that wind can make a huge difference to survey time, and that flying perpendicular can confer a flight time advantage. Small UAVs, which have very slow airspeeds, can very easily be flying in wind, which is 50% of their airspeed. This is why the technique is shown to be so effective, due to the fact that ignoring wind for small, slow, fixed-wing aircraft is a considerable oversight. Comparing this method to previous techniques using a Monte Carlo simulation on randomised polygons shows a significant reduction in flight time.
A Compact Low-Power LoRa IoT Sensor Node with Extended Dynamic Range for Channel Measurements
Authors: Ameloot Thomas , Van Torre Patrick , Rogier Hendrik
Published: July 2018

As sub-GHz wireless Internet of Things (IoT) sensor networks set the stage for long-range, low-data-rate communication, wireless technologies such as LoRa and SigFox receive a lot of attention. They aim to offer a reliable means of communication for an extensive amount of monitoring and management applications. Recently, several studies have been conducted on their performance, but none of these feature a high dynamic range in terms of channel measurement. In this contribution an autonomous, low-power, LoRa-compatible wireless sensor node is presented. The main uses for this node are situated in LoRa channel characterization and link performance analysis. By applying stepped attenuators controlled by a dynamic attenuation adjustment algorithm, this node provides a dynamic range that is significantly larger than what is provided by commercially available LoRa modules. The node was calibrated in order to obtain accurate measurements of the received signal power in dBm. In this paper, both the hardware design as well as some verification measurements are discussed, unveiling various LoRa-related research applications and opportunities.
Light-Weight Integration and Interoperation of Localization Systems in IoT
Authors: Karaagac Abdulkadir , Suanet Pieter , Joseph Wout , Moerman Ingrid , Hoebeke Jeroen
Published: July 2018

As the ideas and technologies behind the Internet of Things (IoT) take root, a vast array of new possibilities and applications is emerging with the significantly increased number of devices connected to the Internet. Moreover, we are also witnessing the fast emergence of location-based services with an abundant number of localization technologies and solutions with varying capabilities and limitations. We believe that, at this moment in time, the successful integration of these two diverse technologies is mutually beneficial and even essential for both fields. IoT is one of the major fields that can benefit from localization services, and so, the integration of localization systems in the IoT ecosystem would enable numerous new IoT applications. Further, the use of standardized IoT architectures, interaction and information models will permit multiple localization systems to communicate and interoperate with each other in order to obtain better context information and resolve positioning errors or conflicts. Therefore, in this work, we investigate the semantic interoperation and integration of positioning systems in order to obtain the full potential of the localization ecosystem in the context of IoT. Additionally, we also validate the proposed design by means of an industrial case study, which targets fully-automated warehouses utilizing location-aware and interconnected IoT products and systems.
Comparison of Data Preprocessing Approaches for Applying Deep Learning to Human Activity Recognition in the Context of Industry 4.0
Authors: Zheng Xiaochen , Wang Meiqing , Ordieres-Meré Joaquín
Published: July 2018

According to the Industry 4.0 paradigm, all objects in a factory, including people, are equipped with communication capabilities and integrated into cyber-physical systems (CPS). Human activity recognition (HAR) based on wearable sensors provides a method to connect people to CPS. Deep learning has shown surpassing performance in HAR. Data preprocessing is an important part of deep learning projects and takes up a large part of the whole analytical pipeline. Data segmentation and data transformation are two critical steps of data preprocessing. This study analyzes the impact of segmentation methods on deep learning model performance, and compares four data transformation approaches. An experiment with HAR based on acceleration data from multiple wearable devices was conducted. The multichannel method, which treats the data for the three axes as three overlapped color channels, produced the best performance. The highest overall recognition accuracy achieved was 97.20% for eight daily activities, based on the data from seven wearable sensors, which outperformed most of the other machine learning techniques. Moreover, the multichannel approach was applied to three public datasets and produced satisfying results for multi-source acceleration data. The proposed method can help better analyze workers’ activities and help to integrate people into CPS.
What It Takes to Lead Sustainability Transitions from the Bottom-Up: Strategic Interactions of Grassroots Ecopreneurs
Authors: Ramos-Mejía Mónica , Balanzo Alejandro
Published: July 2018

This paper studies features of grassroots ecopreneurs’ leadership in their attempt to ignite transformations in production-consumption systems from the bottom up. It builds on a comprehensive approach of change agency based on institutional work, innovation, and learning intermediation literature. The paper describes grassroots ecopreneurs’ interaction strategies to resource business models for sustainability. Empirical data comes from an action research project that consisted of implementing a sustainability experiment in Sur de Bolívar (Colombia). The experiment shows grassroots ecopreneurs’ arrays of activities around making sense, shaping, securing support, nurturing, expanding, and scaling the value proposition, the business infrastructure, the customer interface and the financial model of their ventures. Our findings suggest that leading businesses transition into a more sustainable field requires grassroots ecopreneurs acting as change agents by performing a diverse array of boundary, practice, and knowledge circulation strategies, aiming at securing the societal and environmental impact of their ventures. Change agency manifests in the ways ecopreneurs maneuver to bring about transformations and strive to sustain it. The study contributes to a better understanding of processes of socio-technical change for sustainability in highly diverse institutional contexts, such as (but not exclusively) the developing world. An agency-based approach is proposed as an alternative to a managerial approach.
Host Perceptions of Tourism Impact and Stage of Destination Development in a Developing Country
Authors: Liu Xiaoming (Rose) , Li Jun (Justin)
Published: July 2018

This study makes two important contributions to the existing literature. On the one hand, it investigated tourism impacts as perceived by residents in two important historic cities in India (Puri and Varanasi). On the other hand, it analysed residents’ perceived tourism impacts in relation to their evaluation of stage of destination development. A survey collected valid responses from 570 local residents, who display a high level of agreement concerning the positive economic and sociocultural contributions of tourism. Despite environmental concerns, respondents wish to attract more tourists and further develop infrastructure for tourism. Residents who perceive tourism to be in the development and full development/stagnation stages agree more strongly than those who consider tourism to be in the beginning stage that it increases employment opportunities and seasonality and stipulates cultural activities. In contrast, those who think tourism is in the beginning stage are more concerned about environmental pollution and thus advocate restrictions on the industry. Implications are suggested for tourism research, policy making, and planning.
The New Holistic Paradigm and the Sustainability of Historic Cities in Spain: An Approach Based on the World Heritage Cities
Authors: Martínez Pino Joaquín
Published: July 2018

Linked to the objectives of sustainability of the United Nations, the reflection on the historic city promoted by UNESCO has favored the emergence of a new holistic paradigm that focuses on the capacity of culture to improve the quality of life of people and seeks to recover the historical link among culture, development and sustainability. Based on this context, this paper analyzes the main problems that face Spanish World Heritage Cities in terms of sustainability and livability, and the correlation between the new paradigm and the reality of its current management. This study explored sustainability indicators based on the evolution of the population and the number of visitors. The current protection and management model is reviewed based on the four basic tools identified by UNESCO: Regulatory systems, Knowledge and Planning tools, Financial tools and Civic engagement tools. The joint analysis of UNESCO’s Periodic Reports allows us to identify the shortcomings that point to a disconnection between heritage city management and citizenship. After analyzing the impact of the new paradigm in the Spanish reality, the need to continue deepening its dissemination and accelerating its implementation is evident. In the same way. it is essential to establish and implement models of citizen participation that favor the fulfillment of the sustainability challenges of historic cities.
The Effect of Public Participation on Environmental Governance in China–Based on the Analysis of Pollutants Emissions Employing a Provincial Quantification
Authors: Zhang Tong , Chen Chaofan
Published: July 2018

For a long time, governments and enterprises have been the two main subjects for environmental governance in China. With the growing complexities of environmental issues and the improvement of public environmental awareness, public participation is gradually playing an important role in the process of China’s environmental governance. This paper aims to explore the necessity, the rationale, and the specific effect of public participation on environmental governance in China. A theoretical model is first proposed to illustrate the significance of public participation. Then, an empirical model is built to investigate the impact of public participation on pollutant emissions of the four main pollutants SO2, NOx, COD, and NH4, based on the panel data of 30 provinces from 2011 to 2015 in China. The results and main findings are: (1) public environmental complaints exert a noticeable and positive impact on the reductions of pollutants; (2) this impact varies according to different pollutants, among which reducing SO2 emissions shows the most efficiency; and (3) the impact of public participation on the reduction of pollutants shows the characteristics of hysteresis and regional difference. We find that when the rate of public participation of lagging one period increases by 1%, the reduction of SO2 is 5.03 tons per capita, 1.54 tons per capita, and 0.94 tons per capita in the region of middle, east, and west China, respectively. Therefore, the status of public participation should be strengthened and effective public participation is urgently needed in environmental governance. A systematic cooperative governance among the public, governments, and enterprises needs to be established in the long run.
Representing Sums of Finite Products of Chebyshev Polynomials of Third and Fourth Kinds by Chebyshev Polynomials
Authors: Kim Taekyun , Kim Dae San , Victorovich Dolgy Dmitriy , Ryoo Cheon Seoung
Published: July 2018

Here, we consider the sums of finite products of Chebyshev polynomials of the third and fourth kinds. Then, we represent each of those sums of finite products as linear combinations of the four kinds of Chebyshev polynomials, which involve the hypergeometric function 3F2.
k-Space Magnetism as the Origin of Superconductivity
Authors: Krüger Ekkehard
Published: July 2018

The nonadiabatic Heisenberg model presents a nonadiabatic mechanism generating Cooper pairs in narrow, roughly half-filled “superconducting bands” of special symmetry. Here, I show that this mechanism may be understood as the outcome of a special spin structure in the reciprocal space, hereinafter referred to as “k-space magnetism”. The presented picture permits a vivid depiction of this new mechanism highlighting the height similarity as well as the essential difference between the new nonadiabatic and the familiar Bardeen–Cooper–Schrieffer mechanism.
The Presence of Toxic and Non-Toxic Cyanobacteria in the Sediments of the Limpopo River Basin: Implications for Human Health
Authors: Magonono Murendeni , Oberholster Paul Johan , Shonhai Addmore , Makumire Stanley , Gumbo Jabulani Ray
Published: July 2018

The presence of harmful algal blooms (HABs) and cyanotoxins in drinking water sources poses a great threat to human health. The current study employed molecular techniques to determine the occurrence of non-toxic and toxic cyanobacteria species in the Limpopo River basin based on the phylogenetic analysis of the 16S rRNA gene. Bottom sediment samples were collected from selected rivers: Limpopo, Crocodile, Mokolo, Mogalakwena, Nzhelele, Lephalale, Sand Rivers (South Africa); Notwane (Botswana); and Shashe River and Mzingwane River (Zimbabwe). A physical-chemical analysis of the bottom sediments showed the availability of nutrients, nitrates and phosphates, in excess of 0.5 mg/L, in most of the river sediments, while alkalinity, pH and salinity were in excess of 500 mg/L. The FlowCam showed the dominant cyanobacteria species that were identified from the sediment samples, and these were the Microcystis species, followed by Raphidiopsis raciborskii, Phormidium and Planktothrix species. The latter species were also confirmed by molecular techniques. Nevertheless, two samples showed an amplification of the cylindrospermopsin polyketide synthetase gene (S3 and S9), while the other two samples showed an amplification for the microcystin/nodularin synthetase genes (S8 and S13). Thus, these findings may imply the presence of toxic cyanobacteria species in the studied river sediments. The presence of cyanobacteria may be hazardous to humans because rural communities and farmers abstract water from the Limpopo river catchment for human consumption, livestock and wildlife watering and irrigation.
The Antioxidant Gallic Acid Inhibits Aflatoxin Formation in Aspergillus flavus by Modulating Transcription Factors FarB and CreA
Authors: Zhao Xixi , Zhi Qing-Qing , Li Jie-Ying , Keller Nancy P. , He Zhu-Mei
Published: July 2018

Aflatoxin biosynthesis is correlated with oxidative stress and is proposed to function as a secondary defense mechanism to redundant intracellular reactive oxygen species (ROS). We find that the antioxidant gallic acid inhibits aflatoxin formation and growth in Aspergillus flavus in a dose-dependent manner. Global expression analysis (RNA-Seq) of gallic acid-treated A. flavus showed that 0.8% (w/v) gallic acid revealed two possible routes of aflatoxin inhibition. Gallic acid significantly inhibited the expression of farB, encoding a transcription factor that participates in peroxisomal fatty acid β-oxidation, a fundamental contributor to aflatoxin production. Secondly, the carbon repression regulator encoding gene, creA, was significantly down regulated by gallic acid treatment. CreA is necessary for aflatoxin synthesis, and aflatoxin biosynthesis genes were significantly downregulated in ∆creA mutants. In addition, the results of antioxidant enzyme activities and the lipid oxidation levels coupled with RNA-Seq data of antioxidant genes indicated that gallic acid may reduce oxidative stress through the glutathione- and thioredoxin-dependent systems in A. flavus.
Impact of a single eGFR and eGFR-estimating equation on chronic kidney disease reclassification: a cohort study in primary care
Authors: Hirst Jennifer A , Montes Maria DLA Vazquez , Taylor Clare J , Ordóñez-Mena José M , Ogburn Emma , Sharma Vanshika , Shine Brian , James Tim , Hobbs FD Richard
Published: July 2018

Background

Chronic kidney disease (CKD) is diagnosed using the estimated glomerular filtration rate (eGFR) and the urinary albumin:creatinine ratio (ACR). The eGFR is calculated from serum creatinine levels using the Modification of Diet in Renal Disease (MDRD) or Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations.

Aim

To compare the performance of one versus two eGFR/ACR measurements, and the impact of equation choice, on CKD diagnosis and classification.

Design and setting

Cohort study in primary care in the Thames Valley region of the UK.

Method

Data were from 485 participants aged >60 years in the Oxford Renal Cohort Study with at least two eGFR tests. The proportion of study participants diagnosed and classified into different CKD stages using one and two positive tests were compared. Prevalence of CKD diagnosis and classification by CKD stage were compared when eGFR was calculated using MDRD and CKD-EPI equations.

Results

Participants included in the analysis had a mean age of 72.1 (±6.8) years and 57.0% were female. Use of a single screening test overestimated the proportion of people with CKD by around 25% no matter which equation was used, compared with the use of two tests. The mean eGFR was 1.4 ml/min/1.73 m2 (95% CI = 1.1 to 1.6) higher using the CKD-EPI equation compared with the MDRD equation. More patients were diagnosed with CKD when using the MDRD equation, compared with the CKD-EPI equation, once (64% versus 63%, respectively) and twice (39% versus 38%, respectively), and 16 individuals, all of who had CKD stages 2 or 3A with MDRD, were reclassified as having a normal urinary ACR when using the CKD-EPI equation.

Conclusion

Current guidance to use two eGFR measures to diagnose CKD remains appropriate in an older primary care population to avoid overdiagnosis. A change from MDRD to CKD-EPI equation could result in one in 12 patients with a CKD diagnosis with MDRD no longer having a diagnosis of CKD.
Heterogeneous acidic catalysts for the tetrahydropyranylation of alcohols and phenols in green ethereal solvents
Authors: Azzena Ugo , Carraro Massimo , Modugno Gloria , Pisano Luisa , Urtis Luigi
Published: July 2018

The application of heterogeneous catalysis and green solvents to the set up of widely employed reactions is a challenge in contemporary organic chemistry. We applied such an approach to the synthesis and further conversion of tetrahydropyranyl ethers, an important class of compounds widely employed in multistep syntheses. Several alcohols and phenols were almost quantitatively converted into the corresponding tetrahydropyranyl ethers in cyclopentyl methyl ether or 2-methyltetrahydrofuran employing NH4HSO4 supported on SiO2 as a recyclable acidic catalyst. Easy work up of the reaction mixtures and the versatility of the solvents allowed further conversion of the reaction products under one-pot reaction conditions.
The Millimeter Continuum Size–Frequency Relationship in the UZ Tau E Disk
Authors: Tripathi Anjali , Andrews Sean M. , Birnstiel Tilman , Chandler Claire J. , Isella Andrea , Pérez Laura M. , Harris R. J. , Ricci Luca , Wilner David J. , Carpenter John M. , Calvet N. , Corder S. A. , Deller A. T. , Dullemond C. P. , Greaves J. S. , Henning Th. , Kwon W. , Lazio J. , Linz H. , Testi L.
Published: July 2018

We present high spatial resolution observations of the continuum emission from the young multiple star system UZ Tau at frequencies from 6 to 340 GHz. To quantify the spatial variation of dust emission in the UZ Tau E circumbinary disk, the observed interferometric visibilities are modeled with a simple parametric prescription for the radial surface brightnesses at each frequency. We find evidence that the spectrum steepens with radius in the disk, manifested as a positive correlation between the observing frequency and the radius that encircles a fixed fraction of the emission (R
eff ∝ ν
0.34±0.08). The origins of this size–frequency relation are explored in the context of a theoretical framework for the growth and migration of disk solids. While that framework can reproduce a similar size–frequency relation, it predicts a steeper spectrum than that observed. Moreover, it comes closest to matching the data only on timescales much shorter (≤1 Myr) than the putative UZ Tau age (∼2–3 Myr). These discrepancies are direct consequences of the rapid radial drift rates predicted by models of dust evolution in a smooth gas disk. One way to mitigate that efficiency problem is to invoke small-scale gas pressure modulations that locally concentrate drifting solids. If such particle traps reach high-continuum optical depths at 30–340 GHz with a ∼30%–60% filling fraction in the inner disk (r ≲ 20 au), they can also explain the observed spatial gradient in the UZ Tau E disk spectrum.
Short-lived Circumstellar Interaction in the Low-luminosity Type IIP SN 2016bkv
Authors: Hosseinzadeh Griffin , Valenti Stefano , McCully Curtis , Howell D. Andrew , Arcavi Iair , Jerkstrand Anders , Guevel David , Tartaglia Leonardo , Rui 芮黎 Liming 明 , Mo 莫 Jun 军 , Wang 王晓 Xiaofeng 锋 , Huang 黄 Fang 芳 , Song 宋 Hao 浩 , Zhang 张天 Tianmeng 萌 , Itagaki 板垣 Koichi 公一
Published: July 2018

While interaction with circumstellar material is known to play an important role in Type IIn supernovae (SNe), analyses of the more common SNe IIP and IIL have not traditionally included interaction as a significant power source. However, recent campaigns to observe SNe within days of explosion have revealed narrow emission lines of high-ionization species in the earliest spectra of luminous SNe II of all subclasses. These “flash ionization” features indicate the presence of a confined shell of material around the progenitor star. Here we present the first low-luminosity (LL) SN to show flash ionization features, SN 2016bkv. This SN peaked at M

V
 = −16 mag and has Hα expansion velocities under 1350 km s−1 around maximum light, placing it at the faint/slow end of the distribution of SNe IIP (similar to SN 2005cs). The light-curve shape of SN 2016bkv is also extreme among SNe IIP. A very strong initial peak could indicate additional luminosity from circumstellar interaction. A very small fall from the plateau to the nickel tail indicates unusually large production of radioactive nickel compared to other LL SNe IIP. A comparison between nebular spectra of SN 2016bkv and models raises the possibility that SN 2016bkv is an electron-capture supernova.
Detection of z ∼ 2.3 Cosmic Voids from 3D Lyα Forest Tomography in the COSMOS Field
Authors: Krolewski Alex , Lee Khee-Gan , White Martin , Hennawi Joseph F. , Schlegel David J. , Nugent Peter E. , Lukić Zarija , Stark Casey W. , Koekemoer Anton M. , Fèvre Olivier Le , Lemaux Brian C. , Maier Christian , Rich R. Michael , Salvato Mara , Tasca Lidia
Published: July 2018

We present the most distant detection of cosmic voids (z ∼ 2.3) and the first detection of three-dimensional voids in the Lyα forest. We used a 3D tomographic map of the absorption with an effective comoving spatial resolution of 2.5 h
−1 Mpc and a volume of 3.15 × 105
h
−3 Mpc3, which was reconstructed from moderate-resolution Keck I/LRIS spectra of 240 background Lyman-break galaxies and quasars in a 0.16 deg2 footprint in the COSMOS field. Voids were detected using a spherical overdensity finder calibrated from hydrodynamical simulations of the intergalactic medium (IGM). This allows us to identify voids in the IGM corresponding to voids in the underlying matter density field, yielding a consistent volume fraction of voids in both data (19.5%) and simulations (18.2%). We fit excursion set models to the void radius function and compare the radially averaged stacked profiles of large voids (r > 5 h
−1 Mpc) to stacked voids in mock observations and the simulated density field. Comparing with 432 coeval galaxies with spectroscopic redshifts in the same volume as the tomographic map, we find that the tomography-identified voids are underdense in galaxies by 5.95σ compared to random cells.
Likelihood for Detection of Subparsec Supermassive Black Hole Binaries in Spectroscopic Surveys
Authors: Pflueger Bryan J. , Nguyen Khai , Bogdanović Tamara , Eracleous Michael , Runnoe Jessie C. , Sigurdsson Steinn , Boroson Todd
Published: July 2018

Motivated by observational searches for subparsec supermassive black hole binaries (SBHBs), we develop a modular analytic model to determine the likelihood for detection of SBHBs by ongoing spectroscopic surveys. The model combines the parameterized rate of orbital evolution of SBHBs in circumbinary disks with the selection effects of spectroscopic surveys and returns a multivariate likelihood for SBHB detection. Based on this model, we find that in order to evolve into the detection window of the spectroscopic searches from larger separations in less than a Hubble time, 108
M
⊙ SBHBs must, on average, experience angular momentum transport faster than that provided by a disk with accretion rate

. Spectroscopic searches with yearly cadences of observations are in principle sensitive to binaries with orbital separations less than a few × 104
r

g
(r

g
= GM/c
2 and M is the binary mass), and for every one SBHB in this range, there should be over 200 more gravitationally bound systems with similar properties, at larger separations. Furthermore, if spectra of all SBHBs in this separation range exhibit the active galactic nucleus–like emission lines utilized by spectroscopic searches, the projection factors imply five undetected binaries for each observed 108
M
⊙ SBHB with mass ratio 0.3 and orbital separation 104
r

g
(and more if some fraction of SBHBs is inactive). This model can be used to infer the most likely orbital parameters for observed SBHB candidates and provide constraints on the rate of orbital evolution of SBHBs, if observed candidates are shown to be genuine binaries.
Accurate Determination of Halo Velocity Bias in Simulations and Its Cosmological Implications
Authors: Chen Junde , Zhang Pengjie , Zheng Yi , Yu Yu , Jing Yipeng
Published: July 2018

A long-standing issue in peculiar velocity cosmology is whether the halo/galaxy velocity bias b

v
 = 1 at large scale. The resolution of this important issue must resort to high-precision cosmological simulations. However, this is hampered by another long-standing “sampling artifact” problem in volume-weighted velocity measurement. We circumvent this problem with a hybrid approach. We first measure the statistics free of sampling artifacts, then link them to volume-weighted statistics in theory, and finally solve for the velocity bias. b

v
(determined by our method) is not only free of sampling artifacts but also free of cosmic variance. We apply this method to a ΛCDM N-body simulation of 30723 particles and

box size. For the first time, we determine the halo velocity bias to 0.1%–1% accuracy. Our major findings are as follows: (1)

at

. The deviation from unity (

) increases with k. Depending on halo mass and redshift, it may reach

at

and

at

. The discovered

has a statistically significant impact on the structure growth rate measurement by spectroscopic redshift surveys, including DESI, Euclid, and SKA. (2) Both the sign and the amplitude of b

v
 − 1 depend on mass and redshift. These results disagree with the peak model prediction in that b

v
has much weaker deviation from unity, varies with redshift, and can be bigger than unity. (3) Most of the mass and redshift dependences can be compressed into a single dependence on the halo density bias. Based on this finding, we provide an approximate two-parameter fitting formula.
Is It Small-scale, Weak Magnetic Activity That Effectively Heats the Upper Solar Atmosphere?
Authors: Li K. J. , Xu J. C. , Feng W.
Published: July 2018

Solar chromosphere and coronal heating are big questions for astrophysics. Daily measurement of 985 solar spectral irradiances (SSIs) at the spectral intervals 1–39 nm and 116–2416 nm during 2003 March 1 to 2017 October 28 are utilized to investigate phase relation with respect to daily sunspot number, the Mount Wilson sunspot Index, and the Magnetic Plage Strength Index. All the SSIs form in the abnormally heated layer; the upper photosphere, chromosphere, transition region, and corona are found to be significantly more correlated to weak magnetic activity than to strong magnetic activity, and are found to dance in step with weak magnetic activity. All the SSIs that form in the low photosphere, which indicate the “energy” leaked from the solar subsurface, are found to be more related to strong magnetic activity instead and in anti-phase with weak magnetic activity. In the upper photosphere and chromosphere, strong magnetic activity should lead SSI by about a solar rotation, which also implies that weak magnetic activity should take effect from heating there. It is thus small-scale weak magnetic activity that effectively heats the upper solar atmosphere.
A Gap in the Lower Main Sequence Revealed by Gaia Data Release 2
Authors: Jao 饒 Wei-Chun 惟君 , Henry Todd J. , Gies Douglas R. , Hambly Nigel C.
Published: July 2018

We present the discovery of a gap near M

G
 ≈ 10 in the main sequence on the Hertzsprung–Russell Diagram (HRD) based on measurements presented in Gaia Data Release 2 (DR2). Using an observational form of the HRD with M

G
representing luminosity and G
BP − G
RP representing temperature, the gap presents a diagonal feature that dips toward lower luminosities at redder colors. The gap is seen in samples extracted from DR2 with various distances, and is not unique to the Gaia photometry—it also appears when using near-IR (NIR) photometry (J − K

s
versus

). The gap is very narrow (∼0.05 mag) and is near the luminosity–temperature regime where M dwarf stars transition from partially to fully convective, i.e., near spectral type M3.0V. This gap provides a new feature in the HRD that hints at an underlying astrophysical cause, and we propose that it is linked to the onset of full convection in M dwarfs.
Species conservation profiles of a random sample of world spiders II: Gnaphosidae to Nemesiidae
Authors: Seppälä Sini , Henriques Sérgio , Draney Michael , Foord Stefan , Gibbons Alastair , Gomez Luz , Kariko Sarah , Malumbres-Olarte Jagoba , Milne Marc , Vink Cor , Cardoso Pedro
Published: July 2018

The IUCN Red List of Threatened Species is the most widely used information source on the extinction risk of species. One of the uses of the Red List is to evaluate and monitor the state of biodiversity and a possible approach for this purpose is the Red List Index (RLI). For many taxa, mainly hyperdiverse groups, it is not possible within available resources to assess all known species. In such cases, a random sample of species might be selected for assessment and the results derived from it extrapolated for the entire group - the Sampled Red List Index (SRLI). The current contribution is the second in four papers that will constitute the baseline of a future spider SRLI encompassing 200 species distributed across the world.

A sample of 200 species of spiders were randomly selected from the World Spider Catalogue, an updated global database containing all recognised species names for the group. The 200 selected species where divided taxonomically at the family level and the familes were ordered alphabetically. In this publication, we present the conservation profiles of 45 species belonging to the families alphabetically arranged between Gnaphosidae and Nemesiidae, which encompassed Gnaphosidae, Idiopidae, Linyphiidae, Liocranidae, Lycosidae, Micropholcommatidae, Mysmenidae and Nemesiidae.