bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional diversity of leaf litter mixtures slows decomposition of labile but not recalcitrant carbon over two years
Authors: Grossman Jake J. , Cavender‐Bares Jeannine , Hobbie Sarah E.
Published: February 2020

The decomposition of leaf litter constitutes a major pathway of carbon and nutrient cycling in terrestrial ecosystems. Though it is well established that litter decomposition varies among species, most leaf litter decomposes not alone, but in mixture with litter from heterospecifics. The consequences of this mixing, and of the role of multiple dimensions of plant biodiversity, for litter decomposition are ambiguous, with past research suggesting that mixing diverse litter can speed up, slow down, or have no effect on decomposition. Furthermore, different chemical constituents of litter decompose at different rates, and the consequences of diversity for each of these rates are not completely understood. We created litterbags corresponding to 49 different litter mixtures ranging from one to 12 temperate forest species and allowed them to decompose over 2 yr in a common garden in temperate eastern Minnesota, USA. Following collections at 2, 4, 12, and 24 months, we assessed total mass loss and changes in four classes of litter carbon (soluble cell contents, hemicellulose and bound proteins, cellulose, and lignin/acid unhydrolyzable recalcitrants). Species varied in litter decomposition rate (losing from 8% to 41% of total mass) and they lost soluble cell contents (up to 64% of ash‐free mass) and hemicellulose and bound proteins (69%) much more rapidly over 2 yr than they lost cellulose (40%) and acid‐unhydrolyzable residues (12%). A variety of macro‐ and micronutrients supported litter decomposition, with calcium, in particular, promoting it. In mixtures of litter from 2, 5, or 12 species, neither species richness nor phylogenetic diversity was associated with deviations from expected decomposition rates based on monocultures. Yet more functionally diverse litter mixtures lost labile carbon (soluble cell contents and hemicellulose) significantly more slowly than expected. This novel finding of the effect of litter diversity not on total litter decomposition, but on the decomposition of a particular class of litter compounds elucidates potential consequences of biodiversity for cycling of nutrients and energy in forest ecosystems.
Multienzyme detection and in‐situ monitoring of enzyme activity by bending CE using quantum dots‐based polypeptide substrate
Authors: Qiu Lin , Cui Pengfei , Zhu Zhilan , Xu Mingyu , Jia Wenjing , Sheng Jingyu , Ni Xinye , Zhou Shuwen , Wang Jianhao
Published: February 2020

Multienzyme detection and monitoring enzyme activity in situ are significant for the disease to diagnose. This study aims to develop a quantum dots (QDs)‐based nanoprobe Cyanine5‐DDDLEVLFQFPGLVPRGSGGHHHHHH‐QDs (Cy5‐LEVLVP‐QD), which is able to detect two enzymes inside a bent capillary using CE. Cy5‐LEVLVP and QDs were allowed to bind with each other through metal affinity interaction and then injected the Cy5‐LEVLVP‐QD complex into a capillary with different bends, followed by related enzyme that can cleave the Cy5‐LEVLVP peptide. The fluorescence of Cy5 was excited by QDs due to Förster resonance energy transfer. By monitoring the peaks produced by the original Cy5‐LEVLVP‐QD complex and a significant fluorescence change, sensitive analysis of two different enzymes was conducted. Therefore, the novel approach of using capillaries with semicircular bends could prove particularly useful for enzyme investigating in disease.
Exosome mediated transfer of miRNA‐140 promotes enhanced chondrogenic differentiation of bone marrow stem cells for enhanced cartilage repair and regeneration
Authors: Won Lee Gi , Thangavelu Muthukumar , Joung Choi Min , Yeong Shin Eun , Sol Kim Han , Seon Baek Jong , Woon Jeong Young , Eun Song Jeong , Carlomagno Cristiano , Miguel Oliveira Joaquim , Luis Reis Rui , Khang Gilson
Published: February 2020

Exosomes (EXs) are nanocarrier vesicles with 20‐50 nm dimensions. They are involved in cell proliferation and differentiation and in protecting the integrity of materials. They can be isolated from plasma and immunoreactive components. Recent studies demonstrated their potential role in cartilage regeneration. To enhance their regenerative effect, molecules like microRNA (miR‐140) can be loaded in EX that acts as RNA delivery systems. In this study, we combined EX with miR‐140 to enhance cell differentiation by inducing membrane fusion and consequent miRNA released into the cytoplasm. The carrier RNA complex was successfully synthesized through freeze and thaw method leading to the formation of EX‐containing miR‐140. The EX morphology was assessed through transmission electron microscopy and their miR‐140 uptake efficiency through real‐time polymerase chain reaction (RT‐PCR). The effects on bone marrow stem cells (BMSCs) were evaluated by in vitro cell culture. Cell adhesion and morphology were studied using a bio‐scanning electron microscope and confocal laser scanning microscope. Differentiation BMSCs into chondrocytes was analyzed by RT‐PCR and histology. Our results confirm the bioactive role of EX loaded with miR‐140 in the differentiation of BMSCs into chondrocytes. EXs were biocompatible involving in the cartilage healing process through chromogenic differentiation of BMCS exploiting the tissue engineering route.
Amplitude of low‐frequency fluctuation of resting‐state fMRI in primary nocturnal enuresis and attention deficit hyperactivity disorder
Authors: Jiang Kaihua , Wang Jianbao , Zheng Aibin , Li Lin , Yi Yang , Ding Li , Li Hongxin , Dong Xuan , Zang Yufeng
Published: February 2020

Children with attention deficit hyperactivity disorder (ADHD) and nocturnal enuresis (NE) have similar symptoms, for example, inattention and dysfunction of working memory. We investigate disorder‐specific abnormal activity by using the simple resting‐state functional magnetic resonance imaging (RS‐fMRI) metric amplitude of low‐frequency fluctuation (ALFF). About 18 ADHD, NE, and typically developing children were examined by RS‐fMRI and the child behavior checklist (CBCL) test. One‐way ANOVA were used to compare the ALFF values of the three groups and post hoc was done. We conducted Pearson correlation analysis on the results of the three groups' scales with ALFF values at the discrepant brain areas after then. Significant group effect was found in the bilateral medial prefrontal cortex (MPFC), left inferior temporal gyrus (ITG), left middle temporal gyrus (MTG), cerebellum anterior lobe (CAL), and left inferior parietal lobule (IPL). There was no shared abnormal region for ADHD and NE. Specially, ADHD showed increased ALFF in the bilateral MPFC, left ITG, and CAL and showed decreased ALFF in the left MTG. The children with NE showed increased ALFF in the left IPL. This study reveals the brain mechanism of cognitive changes on ADHD and NE, which provides neuroimaging basis for behavioral differences among different diseases.
Development of the visual system of anchovy larvae, Engraulis anchoita: A microanatomical description
Authors: Miranda Valeria , Cohen Stefanía , Díaz Alcira O. , Diaz Marina V.
Published: February 2020

During the early ontogeny of fish larvae, the accurate development of the visual system plays a key role, because it is involved in locating food, orientation, selection of favorable habitat, and evasion of predators. The structure of the eye of the fish is typical of vertebrates, with some modifications related to the aquatic environment. In the present work, we describe the development of the larval eye of Engraulis anchoita for the first time. Larvae were collected at the Permanent Station of Environmental Studies (EPEA) in coastal waters of the Southwestern Atlantic Ocean during research cruises in 2015 and 2016. We describe the histology of the retina layers, determine the beginning of the functionality of the eye, and discuss a possible synchronization with the development of the digestive tract. This study provides information about the biology of E. anchoita, the most abundant fish species in the southwestern Atlantic Ocean. Also, recent studies have shown responses of the retina and other tissues to the increase in environmental acidity. Therefore, results of this study are also discussed with respect to the possible effect of acidification on the larvae of this species. The continuity of the time series developed at the EPEA will allow monitoring the effect of long‐term environmental and biological variables on the early ontogeny of anchovy in the context of climate change. The high commercial fishing potential of E. anchoita due to its high abundance, as well as its essential role in the trophic web of other commercially valuable fishing resources of Argentina, reinforce the need to continue deepening knowledge about this species.

Research highlights:

Eyes of Engraulis anchoita larvae are functional from early larval stages.

At hatching, the retina is formed by only few layers from which the other layers differentiates during ontogeny.

Focal distance increases with larval growth.
Self‐Directed Learning in Creative Activity: An Ethnographic Study in Technology‐Based Work
Authors: Lemmetty Soila , Collin Kaija
Published: February 2020

Under conditions of rapid changes in working life, there is an urgent need to examine the nature of creativity and learning in organizations. The aim of this study was to investigate the nature of self‐directed learning (SDL) practices in creative activity in technology‐based work. We focus on both individual and collective practices but also on the importance of organizational culture. The data consist of 46 interviews and observational field notes collected from participating organizations. Thematic and ethnographic analyses were utilized as tools to reveal the nature of SDL in creative activity. We found three themes describing of the nature of SDL in creative activity: a combination of individual and collective action, solving common problems through dialogue and discussions, and the organizational culture framing SDL in creative activity. Based on the findings, we provided support for that SDL in creative activity is manifested as a socio‐cultural phenomenon and SDL practices are intertwined with creative activity. We discovered organization cultural frames that can support the realization of SDL and creative activity in working life. However, more research on the relationship between these phenomena and the conditions for their realization is needed.
Age‐ and sex‐specific morphologic changes in the metaphyseal fossa adjacent to epiphyseal tubercle in children and adolescents without hip disorders
Authors: Hosseinzadeh Shayan , Novais Eduardo N. , Maranho Daniel A. , Emami Seyed Alireza , Portilla Gabriela , Kim Young‐Jo , Kiapour Ata M.
Published: February 2020

The epiphyseal tubercle plays an important role in epiphyseal stabilization. While the majority of studies have focused on tubercle morphology, there is a paucity of information on the morphological features of the metaphyseal fossa, where the tubercle sits on the metaphysis. The goal of this study was to determine the developmental changes in the capital femoral metaphyseal fossa. Computed tomography of the pelvis from 80 children and adolescents 8‐15 years old were used to create three‐dimensional models of the proximal femur. Depth, width, length, and surface area of the metaphyseal fossa were measured and the impact of age and sex on fossa morphology was assessed using the linear regression and two‐way analysis of variance, respectively. The metaphyseal fossa was located in the posterosuperior quadrant of the metaphysis without any variations in the location with increasing age (P > .1). However, with increasing age, there was a reduction in all metaphyseal fossa measurements including the depth, length, width, and surface area (P < .01). No significant differences were noted for the metaphyseal fossa measurements between males and females (P > .1). The metaphyseal fossa reduces in size from 8 to 15 years of age in a similar fashion in males and females. As the metaphyseal fossa adjacent to the tubercle matches the area where a focal radiolucency has been observed in early slipped capital femoral epiphysis (SCFE), further studies should clarify the mechanisms by which the interlocking interaction of the epiphyseal tubercle and its fossa contributes to or is affected by SCFE.
Land use drives nitrous oxide dynamics in estuaries on regional and global scales
Authors: Reading Michael J. , Tait Douglas R. , Maher Damien T. , Jeffrey Luke C. , Looman Arun , Holloway Ceylena , Shishaye Haile A. , Barron Summer , Santos Isaac R.
Published: February 2020

Urban and agricultural development of coastal catchments is known to increase dissolved nitrogen inputs into estuaries; however, much less is known about how land use influences the production of the powerful greenhouse gas nitrous oxide (N2O). Here, we assess dissolved N2O dynamics in four nearby estuaries across a regional land use gradient and summarize the literature to put the observations into global perspective. During summer dry conditions, N2O saturation ranged from 131.4% ± 45.0% in the most pristine system (28% modified) to 198.6% ± 52.3% within the most modified urban system (91% modified). The N2O saturation in the wetter winter campaign was higher and more variable than the summer dry campaign (range 84.7–677.7%) likely due to direct transport of N2O into the estuaries from catchment runoff and/or produced through denitrification fueled by high nitrate inputs. During both seasons, N2O was lowest in areas adjacent to fringing mangroves and highest in upstream fresh/saltwater mixing areas. Coupling our results with previously published N2O data from 50 estuarine systems worldwide revealed that estuarine N2O increases concomitantly with catchment modification, dissolved inorganic nitrogen availability, and decreasing oxygen concentrations. Based on these results, a 1% increase in anthropogenic modification to global catchments (i.e., agricultural development and/or urbanization) may increase estuarine N2O saturation by 2.6% ± 1.2%. These findings indicate that future estuarine N2O emissions are likely to increase as anthropogenic modification of coastal catchments intensifies.
The interaction of physical and biological factors drives phytoplankton spatial distribution in the northern California Current
Authors: Krause Jeffrey W. , Brzezinski Mark A. , Largier John L. , McNair Heather M. , Maniscalco Michael , Bidle Kay D. , Allen Andrew E. , Thamatrakoln Kimberlee
Published: February 2020

Transitions in phytoplankton community composition are typically attributed to ecological succession even in physically dynamic upwelling systems like the California Current Ecosystem (CCE). An expected succession from a high‐chlorophyll (~ 10 μg L−1) diatom‐dominated assemblage to a low‐chlorophyll (< 1.0 μg L−1) non‐diatom dominated assemblage was observed during a 2013 summer upwelling event in the CCE. Using an interdisciplinary field‐based space‐for‐time approach leveraging both biogeochemical rate measurements and metatranscriptomics, we suggest that this successional pattern was driven primarily by physical processes. An annually recurring mesoscale eddy‐like feature transported significant quantities of high‐phytoplankton‐biomass coastal water offshore. Chlorophyll was diluted during transport, but diatom contributions to phytoplankton biomass and activity (49–62% observed) did not decline to the extent predicted by dilution (18–24% predicted). Under the space‐for‐time assumption, these trends infer diatom biomass and activity and were stimulated during transport. This is hypothesized to result from decreased contact rates with mortality agents (e.g., viruses) and release from nutrient limitation (confirmed by rate data nearshore), as predicted by the Disturbance‐Recovery hypothesis of phytoplankton bloom formation. Thus, the end point taxonomic composition and activity of the phytoplankton assemblage being transported by the eddy‐like feature were driven by physical processes (mixing) affecting physiological (release from nutrient limitation, increased growth) and ecological (reduced mortality) factors that favored the persistence of the nearshore diatoms during transit. The observed connection between high‐diatom‐biomass coastal waters and non‐diatom‐dominated offshore waters supports the proposed mechanisms for this recurring eddy‐like feature moving seed populations of coastal phytoplankton offshore and thereby sustaining their activity.
Effect of Mesh Size on Microscreen Filtration Combined with Foam Fractionation for Solids Removal in Recirculating Aquacultural Seawater
Authors: Ji Mingdong , Li Haijun , Li Jianping , Ye Zhangying , Zhu Songming
Published: February 2020

Microscreen filtration and foam fractionation have been considered as effective solids removal technologies in marine recirculating aquaculture systems (RAS). To figure out the appropriate mesh size for highly efficient solids removal and management, this study investigated the effects of different mesh sizes (120, 90, 60, and 40 μm) on a combination treatment of solids filtration and fractionation removal in RAS for grouper. The experimental results showed that filtration and total removal efficiency increased with the decrease of mesh size on the whole; however, the produced fine particles (<20 μm) increased simultaneously due to the breakup of relatively large particles caused by filtration. Although the best total removal efficiency was 32.33%, obtained with mesh size 40 μm, it was accompanied with a serious particle breakup. We suggest that the large amounts of fine particles are a big risk. Therefore, 60-μm mesh was better in terms of solids removal efficiency and fine particles management. The effect of mesh size on microscreen filtration was undoubted, while the indirect effect on foam fractionation was negligible. However, fractionation could be effective for removing partial fine particles and its efficiency was quite close to that of filtration. Foam fractionation is thus recognized as an essential treatment in marine RAS.
Liraglutide 3.0 mg and Intensive Behavioral Therapy (IBT) for Obesity in Primary Care: The SCALE IBT Randomized Controlled Trial
Authors: Wadden Thomas A. , Tronieri Jena Shaw , Sugimoto Danny , Lund Michael Taulo , Auerbach Pernille , Jensen Camilla , Rubino Domenica
Published: February 2020

Objective

Previous studies have shown additive weight loss when intensive behavioral therapy (IBT) was combined with weight‐loss medication. The present multisite study provides the first evaluation, in primary care, of the effect of the Centers for Medicare and Medicaid Services–based IBT benefit, delivered alone (with placebo) or in combination with liraglutide 3.0 mg.

Methods

The Satiety and Clinical Adiposity—Liraglutide Evidence in individuals with and without diabetes (SCALE) IBT was a 56‐week, randomized, double‐blind, placebo‐controlled, multicenter trial in individuals with obesity who received liraglutide 3.0 mg (n = 142) or placebo (n = 140) as an adjunct to IBT.

Results

At week 56, mean weight loss with liraglutide 3.0 mg plus IBT was 7.5% and 4.0% with placebo combined with IBT (estimated treatment difference [95% CI]–3.4% [–5.3% to –1.6%], P = 0.0003). Significantly more individuals on liraglutide 3.0 mg than placebo achieved ≥ 5% weight loss (61.5% vs. 38.8%; odds ratio [OR] 2.5% [1.5% to 4.1%], P = 0.0003), > 10% weight loss (30.5% vs. 19.8%; OR 1.8% [1.0% to 3.1%], P = 0.0469), and > 15% weight loss (18.1% vs. 8.9%; OR 2.3% [1.1% to 4.7%], P = 0.0311). Liraglutide 3.0 mg in combination with IBT was well tolerated, with no new safety signals identified.

Conclusions

In a primary care setting, Centers for Medicare and Medicaid Services–based IBT produced clinically meaningful weight loss at 56 weeks, enhanced by the addition of liraglutide 3.0 mg.
Unicentric Castleman disease and lymphoepithelial cyst of the parotid: A case report and review of the literature
Authors: Reny Danielle , Dalal Sharvari , Jhala Darshana , Mirza Natasha
Published: February 2020

Objectives

Present the first reported case of unicentric Castleman disease and lymphoepithelial cyst of the parotid in an HIV‐negative adult.

Methods

Retrospective case presentation.

Results

Castleman disease is an uncommon disorder of benign hypervascular lymphoid hyperplasia with an estimated incidence rate of 15.9‐19.1 cases per million person‐years (Leukemia & Lymphoma, 56, 2015: 1252). Parotid involvement is extremely rare, with less than 30 cases reported in the literature (Case Reports in Otolaryngology, 2015, 2015: 1). Benign lymphoepithelial cysts (BLECs) are another rare parotid lesion presenting most commonly in HIV‐positive patients. Here we present the case of a 42‐year‐old HIV‐negative male who presented with 3 cm parotid mass. The patient underwent superficial parotidectomy with final pathology demonstrating BLEC with the hyaline‐vascular subtype of Castleman disease. The patient has had no recurrence of symptoms in a 3‐month follow‐up period.

Conclusions

The practitioner should consider unicentric Castleman disease and BLEC in HIV‐negative patients presenting with a new head and neck mass.
A conceptual model development of the impact of higher education service quality in guaranteeing edu‐tourists' satisfaction and behavioral intentions
Authors: Rahimizhian Sima , Avci Turgay , Eluwole Kayode K.
Published: February 2020

This conceptual study proposed that university service quality is of significant influence in guaranteeing education tourist's (edu‐tourist) satisfaction, recommendation intention, and repurchase intention. The study considers the universities as tourism markets that attract edu‐tourists and put forward that the level of service quality provided by institutions can influence on the satisfaction of edu‐tourist and their post‐behavioral intention in an educational tourism context. This paper analyzed several previous studies and discussed service quality factors affecting edu‐tourist's satisfaction and behavioral intentions using various databases such as social sciences and psychology. The theoretical framework of the means‐end approach was used to evaluate service quality dimensions. The findings revealed the most significant factors affecting edu‐tourist's perception of service quality, satisfaction, and behavioral intentions. Overall, the campus facilities perceived to be the most prominent factor in satisfying edu‐tourists. Recommendations for future research relating the crucial determinants of service quality in influencing consumers' behavior are discussed.
The role of winding pattern on filament wound composite cylinders under radial compression
Authors: Lisbôa Tales V. , Almeida José Humberto S. , Dalibor Ingo H. , Spickenheuer Axel , Marczak Rogério J. , Amico Sandro C.
Published: February 2020

Filament wound (FW) structures present a geometric characteristic in their helical layers: the winding pattern. The pattern, however, is usually disregarded in conventional experimental or numerical approaches even though it can affect the behavior of FW structures, and most studies that account for the pattern are only theoretical. This study aims at deepening the understanding of pattern effects via a comprehensive experimental campaign focusing on composites cylinders under radial compression. Ten winding patterns were considered, from 1 to 10 units along the circumferential direction. Strength, stiffness, absorbed energy and failure mechanisms were evaluated. The results show that the pattern may have a strong influence on both maximum bearing load and absorbed energy, whereas stiffness is less affected.
Open hole tension and compression behavior of 3D braided composites
Authors: Shuangqiang Liang , Qihong Zhou , Ge Chen , Ko Frank
Published: February 2020

The damage tolerant behavior of 3D braided composites is evaluated in terms of the open‐hole notch strength test under tensile and compressive loading. The influence of fiber architecture is evaluated by comparing 3D braid with and without axial yarns as well as laminated composites based on ASTM quasi‐static tension and compression testing standard. The results show that the notched and un‐notched properties of the two types of 3D braided composites are similar under tension and compression loading. Comparing to laminates, both types of 3D braided composites demonstrated superior notch insensitivity than laminated composites. For the failure behavior of the 3D braided composites, under tension loading, crack of both notched specimens tends to propagate along the notch and finally render the specimen to failure. Clear cracks usually presented on the samples without axial yarns, while not for the specimens with axial yarn. Under compression loading, the two types of 3D braided composite are also macroscopically similar, showing transverse fracture. The modified Fabric Geometry Model is used to predict the tensile properties of 3D braided composite. The predicted and experimental results are shown to be in good agreement.
Healing after traumatic events: Aligning interventions with cultural background and religious and spiritual beliefs
Authors: Heath Melissa A. , Cutrer‐Párraga Elizabeth A.
Published: February 2020

Historically, disaster response efforts have focused primarily on basic physical survival and safety—addressing medical emergencies and ensuring adequate shelter and supplies of food and water. However, in addition to physical survival, relief efforts must also consider strategies to promote emotional healing and psychological well‐being. In particular, those who intervene must consider the acceptability of intervention strategies, taking into account survivors' cultural background, religious customs, and spiritual beliefs. This article offers recommendations to better align school‐based therapeutic interventions with children's religious and spiritual beliefs.
Entanglement between Distant Regions in Disordered Quantum Wires
Authors: Schreiber Yishai , Berkovits Richard
Published: February 2020

The entanglement negativity for spinless fermions in a strongly disordered 1D Anderson model is studied. For two close regions, the negativity is log‐normally distributed, and is suppressed by repulsive interactions. With increasing distance between the regions, the typical negativity decays, but there remains a peak in the distribution, also at high values, representing highly entangled distant regions. For intermediate distances, in the noninteracting case, two distinct peaks are observed. As a function of interaction strength, the two peaks merge into each other. The abundance and nature of these entangled regions is studied. The relation to resonances between single‐particle eigenstates is demonstrated. Thus, although the system is strongly disordered, it is nevertheless possible to encounter two far‐away regions which are entangled.
Augmented reality for narrow area navigation in jaw surgery: Modified tracking by detection volume subtraction algorithm
Authors: Budhathoki Srijana , Alsadoon Abeer , Prasad P.W.C. , Haddad Sami , Maag Angelika
Published: February 2020

Background and Aim

Jaw surgery based on augmented reality (AR) still has limitations in terms of navigating narrow areas. Surgeons need to avoid nerves, vessels, and teeth in their entirety, not just root canals. Inaccurate positioning of the surgical instrument may lead to positional or navigational errors and can result in cut blood vessels, nerve channels, or root canals. This research aims to decrease the positional error during surgery and improve navigational accuracy by reducing the positional error.

Methodology

The proposed 2D/3D system tracks the surgical instrument, consisting of the shaft and the cutting element, each part being assigned a different feature description. In the case of the 3D position estimation, the input vector is composed of image descriptors of the instrument and the output value consists of 3D coordinates of the cutter.

Results

Sample results from a jawbone—maxillary and mandibular jaw—demonstrate that the positional error is reduced. The system, thus, led to an improvement in alignment of the video accuracy by 0.25 to 0.35 mm from 0.40 to 0.55 mm and a decrease in processing time of 11 to 14 frames per second (fps) against 8 to 12 fps of existing solutions.

Conclusion

The proposed system is focused on overlaying only on the area to be operated on. Thus, this AR‐based study contributes to accuracy in navigation of the deeper anatomical corridors through increased accuracy in positioning of surgical instruments.
Distributed output‐feedback finite‐time tracking control of nonaffine nonlinear leader‐follower multiagent systems
Authors: Chen Gang , Xiang Hongbing , Dai Jiahua
Published: February 2020

The distributed output‐feedback tracking control for a class of networked multiagents in nonaffine pure‐feedback form is investigated in this article. By introducing a low‐pass filter and some auxiliary variables, we first transform the nonaffine system into the affine form. Then, the finite‐time observer is designed to estimate the states of the newly derived affine system. By applying the fraction dynamic surface control approach and the neural network‐based approximation technique, the distributed output‐feedback control laws are proposed and it is proved that the tracking errors converge to an arbitrarily small bound around zero in finite time. Finally, some simulation examples are provided to confirm the effectiveness of the developed method.
Silver nanostructures embedding in polymethyl methacrylate patterns fabricated using proton beam writing
Authors: Mongwaketsi Nametso , Matinise Nolubabalo , Madito Jack , Khumalo Zakhelumuzi , Mayedwa Noluthando , Mtshali Christopher , Pieters Caswell , Nkosi Mlungisi
Published: February 2020

Proton beam writing (PBW) on polymethyl methacrylate (PMMA) followed by embedding of biosynthesized silver nanoparticles (AgNPs) was investigated. This is the first demonstration of the use of 3 MV Tandetron accelerator at iThemba LABS for fabricating patterns using PBW technique. The irradiation of PMMA was carried out using 3.0‐MeV proton beam focused down to micrometer spot size. The fluence of protons was counted as electrical charge per unit monitored by exposure time, beam current, and irradiated area. As expected, the PMMA behaved as a positive resist because of chain scissioning induced from the interaction with proton beam. Morphological characterization using scanning electron microscope (SEM) revealed fabrication of square‐like patterns, and atomic force microscopy (AFM) provided the possibility of observing the presence of AgNPs that stood out of the PMMA matrix.
Amino‐Acid‐Mediated Aerobic Oxidation of Organoborons for the Synthesis of Phenolic Derivatives Using Single Electron Transfer
Authors: Gujjarappa Raghuram , Vodnala Nagaraju , Garg Aakriti , Hazra Chinmoy K. , Gupta Sreya , Malakar Chandi C.
Published: February 2020

An efficient amino‐acid‐mediated ipso‐hydroxylation of arylboronic acids, aryl boronate esters and aryl trifluoroborates to aryl alcohols has been described. The current protocol was realized by using sub‐stoichiometric amount of l‐histidine in presence of triethylamine under aerobic conditions in DMF as solvent. This amino‐acid‐mediated process provides an alternative route for the hydroxylation of organoborons through in situ generation of hydrogen peroxide. The present protocol explores the synthetic utility of amino acids as organocatalysts for the preparation of aryl alcohols. It was observed that l‐histidine plays an important role for the conversion of aerial oxygen in to hydrogen peroxide via thermal excitation process followed by thermal degradation of Et3N. The developed approach holds good for a wide range of compounds with excellent yields and competent functional group tolerance.
Kinetic Modeling and Experimental Investigation of Hydro‐Catalytic Upgrading of Anisole as a Model Compound of Bio‐Oils Derived from Fast Pyrolysis of Lignin over Co/γ‐Al2O3
Authors: Saidi Majid , Baharan Seyedeh Nesa Rahbar
Published: February 2020

Hydro‐catalytic upgrading of anisole, as a representative of methoxy functionality model component of lignin‐derived bio‐oil over synthesized Co/γ–Al2O3 catalyst, has been studied to determine the reactions kinetics and network. The catalytic conversion was carried out in a fixed‐bed tubular micro‐activity flow reactor at 573–723 K, 8 bar, and the space velocity of 3–120 (g of Anisole)/(g of catalyst×h), in the presence of hydrogen. According to selectivity‐conversion data, anisole was converted to benzene and toluene via hydrodeoxygenation (HDO), phenol via hydrogenolysis and phenol derivatives via alkylation and trans‐alkylation. Furthermore, a pseudo‐first‐order model has been developed to estimate the apparent activation energy and kinetic constants. Toluene formation pathway possessed the minimum apparent activation energy. From experimental results, hydrogenolysis and HDO are characterized by the highest and lowest rate, respectively among various reactions on Co/γ–Al2O3. The overall rate of anisole conversion over Co/γ–Al2O3 was higher than that of commercial CoMo/γ–Al2O3 catalyst. Sensitivity analysis of operating conditions indicated that operating temperature increment improved the overall anisole conversion and selectivity to benzene as the main HDO product.
Catalytic Conversion of Biomass‐Derived 2, 5‐Dimethylfuran into Renewable p‐Xylene over SAPO‐34 Catalyst
Authors: Gao Zhebang , Feng Yunchao , Zhang Liangqing , Zeng Xianhai , Sun Yong , Tang Xing , Lei Tingzhou , Lin Lu
Published: February 2020

In this work, ∼75% selectivity to p‐xylene (pX) has been achieved from biomass‐derived 2, 5‐dimethylfuran (DMF) and ethylene over SAPO‐34. The pX selectivity reached a maximum after 12 h and maintained significantly stable when prolonging the reaction time. This might be due to the small Brønsted/Lewis ratio and the hierarchical structures of SAPO‐34. Stability tests suggested that SAPO‐34 may be resistant to deactivation under the optimized reaction conditions. Besides, it was found that SAPO‐11 showed similar catalytic performances to SAPO‐34. In summary, these novel SAPO catalysts might provide an alternative for the selective production of renewable aromatics from biomass‐derived feedstock.
Dual C‐C Bond Forming Heck and Sonogashira Couplings Followed by Hydroarylation: Synthesis of Tricyclic Frameworks
Authors: Ramesh Karu , Ravikishore Dakoju , Satyanarayana Gedu
Published: February 2020

Herein, a concise approach to construct the novel tricyclic ether frameworks, is presented. Microwave‐assisted dual C‐C bond‐forming palladium‐catalyzed intramolecular Heck/intermolecular Sonogashira couplings were implemented, for the synthesis of dihydrobenfurans bearing acetylene moiety, followed by acid‐induced intramolecular hydroarylation reaction of the crude reaction mixture furnished the tricyclic ether systems. Notably, these tricyclic ether frameworks have been achieved, in excellent yields, through a single column chromatography process.
Direct Electrochemical Aptamer‐Based Detection of Digoxin
Authors: Wijesinghe Mahadurage Sachintha , Ngwa Wilfred , Chow Kwok‐Fan
Published: February 2020

Here we report a signal‐on electrochemical aptamer‐based (E‐AB) sensor for the detection of digoxin at clinically relevant levels. Digoxin is a plant‐based medication that is prescribed to treat patients with congestive heart failure and chronic atrial fibrillation and atrial flutter. Digoxin has a narrow therapeutic range index of between 0.5 ng/mL and 2.0 ng/mL. The aptamer used in this study is a 50‐base DNA oligonucleotide that has been proven to have high affinity toward digoxin. One end of the aptamer is immobilized on a gold electrode surface and the other end is tagged with a methylene blue molecule, which is used as a redox label. Like other signal‐on E‐AB sensors, once the target binds to the aptamer‐modified electrode, the methylene blue reduction current increases. The developed E‐AB digoxin sensor provides a distinct and amplified peak current response in the therapeutic range of 0.5 ng/mL to 2.0 ng/mL in a phosphate buffer saline solution. The advantage of this detection method is that it allows an aptamer‐modified electrode to perform single‐step and reagentless sensing. We suggest this approach as a conceptual pathway to point‐of‐care E‐AB digoxin sensor design.
Molecular Nanowire Bonding to Epitaxial Single‐Layer MoS2 by an On‐Surface Ullmann Coupling Reaction
Authors: Rodríguez‐Fernández Jonathan , Haastrup Mark J. , Schmidt Søren B. , Grønborg Signe S. , Mammen Mathias H. R. , Lauritsen Jeppe V.
Published: February 2020

Lateral heterostructures consisting of 2D transition metal dichalcogenides (TMDCs) directly interfaced with molecular networks or nanowires can be used to construct new hybrid materials with interesting electronic and spintronic properties. However, chemical methods for selective and controllable bond formation between 2D materials and organic molecular networks need to be developed. As a demonstration of a self‐assembled organic nanowire‐TMDC system, a method to link and interconnect epitaxial single‐layer MoS2 flakes with organic molecules is demonstrated. Whereas pristine epitaxial single‐layer MoS2 has no affinity for molecular attachment, it is found that single‐layer MoS2 will selectively bind the organic molecule 2,8‐dibromodibenzothiophene (DBDBT) in a surface‐assisted Ullmann coupling reaction when the MoS2 has been activated by pre‐exposing it to hydrogen. Atom‐resolved scanning tunneling microscopy (STM) imaging is used to analyze the bonding of the nanowires, and thereby it is revealed that selective bonding takes place on a specific S atom at the corner site between the two types of zig‐zag edges available in a hexagonal single layer MoS2 sheet. The method reported here successfully combining synthesis of epitaxial TMDCs and Ullmann coupling reactions on surfaces may open up new synthesis routes for 2D organic‐TMDC hybrid materials.
Rapid determination of organophosphorus pesticides in edible vegetable oils by direct microextraction using magnetic mesoporous silica microspheres
Authors: Wu Jian‐Yuan , Zhang Hui‐Xian , Peng Xi‐Tian
Published: February 2020

This study describes a rapid and sensitive method for the detection of four organophosphorus pesticides in edible vegetable oils by magnetic mesoporous silica microsphere (mSiO2@Fe3O4) extraction. Organophosphorus pesticides were directly extracted from oil sample using mSiO2@Fe3O4 after diluting with n‐hexane. Compared with traditional sample preparation methods, this procedure is less time consuming and it does not necessitate environmentally unfriendly solvent extraction / centrifugation processes. Moreover, the matrix effect can also be suppressed by size‐exclusion interaction due to mesoporous structure of mSiO2@Fe3O4 and large molecules of fat. Clean analytes were analyzed by liquid chromatography with tandem mass spectrometry. Variables affecting extraction of organophosphorus pesticides were optimized. Under the optimized conditions, the whole pretreatment process could be accomplished within 10 min. Acceptable linearity in the range of 5–1000 ng/g was obtained for four organophosphorus pesticides with satisfactory R2 of 0.9858∼0.9983. The limits of detection ranged from 0.2 to 0.6 ng/g. The method recoveries at three spiked concentration levels (10, 100 and 1000 ng/g) were from 92.1 to 108.6% with interday and intraday relative standard deviations less than 5.9 and 13.4%, respectively. Finally, the established method was successfully applied for the determination of organophosphorus pesticides in real edible vegetable oils.
Creep of reinforced high‐strength concrete‐containing industrial by‐products silica fume and slag
Authors: Chen Pang , Zheng Wenzhong , Zhou Xianyu
Published: February 2020

This study aimed to examine the creep of reinforced high‐strength concrete (HSC) containing industrial byproducts, silica fume (SF), and slag (SL). In total, 36 HSC specimens were prepared and tested for creep. Three specimens were used for the plain HSC creep test, 6 specimens were used for the reinforced HSC creep test, and 27 specimens were used for companion shrinkage tests. The applicability of existing creep models in predicting the creep of HSC containing SF and SL were evaluated. In addition, the effect of compressive strength and reinforcement ratio on reinforced HSC was investigated. Moreover, a new procedure to calculate the creep of reinforced HSC columns, based on the modified creep model and an existing creep recovery model, was developed. Finally, a parametric analysis was conducted to investigate the effects of compressive strength, reinforcement ratio, stress–strength ratio, loading age, and volume–surface ratio on reinforced HSC.
A Hybrid Energy Efficient Cooperative Transmission Scheme in Multi‐Hop Wireless Sensor Networks
Authors: Peng Yuyang , Li Jun , Jiang Xue‐Qin
Published: February 2020

This letter proposes a hybrid cooperative transmission scheme for energy reduction in multi‐hop clustered wireless sensor networks (WSNs) where single‐input single‐output (SISO) and spatial modulation (SM)‐based cooperative MIMO (CMIMO‐SM) schemes are jointly used as the transmission candidates. In this work, we consider a linear all‐transmission scenario where the intermediate clusters act not only as forwarding clusters but also transmitting clusters. The numerical experiments demonstrate that the energy reduction of WSN is achieved by choosing the optimal hop length and appropriate transmission candidate. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Thermal behavior of woody residues in a reduced‐oxygen atmosphere using Macro‐thermogravimetric technique
Authors: Nguyen Hong Nam , Van De Steene Laurent
Published: February 2020

In the context of sustainable development, co‐gasification or co‐firing of biomass residues and coal is becoming a relevant solution to mitigate the negative impact of fossil fuels. For this reason, it is crucial to understand the characteristics, as well as the thermal behaviors of these residues, especially in a low‐oxygen condition that is often found in industrial processes. In this study, woody residues, namely bamboo and rubberwood chips that are abundantly available in Vietnam were characterized. Thermal degradation of these residues in 4 % oxygen was also conducted using a Macro‐thermogravimetric analyzer, from room temperature to 700 °C. The results showed that bamboo had a higher volatile matter and a higher hemicellulose content compared to rubberwood chips, hence is easier for ignition in a thermochemical conversion process. Regarding the thermal behaviors of these residues in a reduced‐oxygen condition, three stages could be clearly observed in the TGA‐DTG curves. Rubberwood chip had a higher ignition temperature and higher temperatures of maximum mass loss rate compared to bamboo chip. Results could contribute to the understanding of the thermal behaviors of these biomass feedstocks in order to improve the efficiency of co‐gasification or co‐firing processes.
Synthesis and application of novel Fe‐MIL‐53/GO nanocomposite for photocatalytic degradation of reactive dye from aqueous solution
Authors: Vu Hoa T. , Tran Linh T. , Le Giang H. , Nguyen Quang K. , Vu Tan M. , Vu Tuan A.
Published: February 2020

The composite of Fe‐MIL‐53 and graphene oxide (GO) was successfully prepared using solvothermal method to crystallize Fe‐MIL‐53 on GO layers. The Fe‐MIL‐53/GO composite was characterized by XRD, isotherms of N2 adsorption– desorption (BET), TEM, FTIR, and Energy dispersive X‐Ray (EDX). From TEM result, it revealed the formation of very small Fe‐MIL‐53 particles of 10 ‐20 nm well dispersed on GO surface. The photocatalytic activity of Fe‐MIL‐53/GO nanocomposite for the degradation of reactive dye (reactive red‐RR195) in aqueous solution was examined and evaluate. The red‐RR195 removal efficiency reached 96 % after 60 min of reaction under irradiation of simulated sunlight, indicating highly photocatalytic activity of this nano composite. In addition, this composite also showed much higher photocatalytic activity as compared to that of pure Fe‐MIL‐53, this clearly indicated the synergistic effect between Fe‐MIL‐53 and GO. Therefore, the novel Fe‐MIL‐53/GO can be considered as a highly efficient photocatalyst for degradation of reactive dye from aqueous solution.
Evaluation of the efficiency of three different mineral adsorbents in the removal of pollutants in samples from a tropical spring in Northeastern Brazil
Authors: Guimarães Neto José Osmar Andrade , Aguiar Terencio Rebello
Published: February 2020

Human water sources are increasingly threatened around the world due to various sources of pollution such as agriculture and industry. The objective of this study was to evaluate three new adsorbents as pollutant remedies for subsequent application in the Joanes River located in the State of Bahia in Brazil. The specific pollutants were nitrogen, phosphorus (P), aluminum (Al), iron (Fe), cyanobacteria, and saxitoxins. Initially, studies (pH 7 and 22°C) were performed with samples contaminated in the laboratory with phosphorus (P), nitrate (

), and ammonia (NH3), to select the most efficient adsorbent and to determine the equilibrium time. Pumice bituminous coal was found to have the best efficiencies (≥70%) at 360 min (equilibration time). The experimental data did not fit the Langmuir and Freundlich model. The bituminous coal with pumice stone was then applied to water samples from a designated capture point of the Joanes springs, a river system that is responsible for supplying the city of Salvador and the metropolitan region, located on the northern coast of Bahia. The removal efficiency analyses were performed on a DR6000 UV/VIS SPECTROPHOTOMETER, using the methodology defined in the Standard Methods 2017, after which this adsorbent was subjected to scanning electron microscopy. As a result, removal efficiencies (≥98%) were obtained for all contaminants (nitrogen, phosphorus (P), aluminum (Al), iron (Fe), cyanobacteria, and saxitoxins) as well as a highly heterogeneous layer pointed by SEM images, further demonstrating the adsorbent potential as a efficient alternative in environmental control after additional studies.

Practitioner points

Pumice bituminous coal has proven to be an excellent adsorbent for a wide range of pollutants such as phosphorus, nitrogen, ammonia, toxins, cyanobacteria, and metals.

The adsorbent promoted a high reduction in phosphorus concentrations (3.40 mg/L to 0.01 mg/L), about 98% and 81% for cyanobacteria (12,850 Cel/ml to 2,560 Cel/ml).

The adsorbent promoted a high reduction in concentrations of 98% saxitoxins (4.32 µg/L to 0.2 µg/L).
Learning decision trees through Monte Carlo tree search: An empirical evaluation
Authors: Nunes Cecília , De Craene Mathieu , Langet Hélène , Camara Oscar , Jonsson Anders
Published: February 2020

Decision trees (DTs) are a widely used prediction tool, owing to their interpretability. Standard learning methods follow a locally optimal approach that trades off prediction performance for computational efficiency. Such methods can however be far from optimal, and it may pay off to spend more computational resources to increase performance. Monte Carlo tree search (MCTS) is an approach to approximate optimal choices in exponentially large search spaces. We propose a DT learning approach based on the Upper Confidence Bound applied to tree (UCT) algorithm, including procedures to expand and explore the space of DTs. To mitigate the computational cost of our method, we employ search pruning strategies that discard some branches of the search tree. The experiments show that proposed approach outperformed the C4.5 algorithm in 20 out of 31 datasets, with statistically significant improvements in the trade‐off between prediction performance and DT complexity. The approach improved locally optimal search for datasets with more than 1,000 instances, or for smaller datasets likely arising from complex distributions.

This article is categorized under:

Algorithmic Development > Hierarchies and Trees

Application Areas > Data Mining Software Tools

Fundamental Concepts of Data and Knowledge > Data Concepts