bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reconfigurable field‐programmable gate array‐based on‐chip learning neuromorphic digital implementation for nonlinear function approximation
Authors: Gholami Morteza , Zaman Farsa Edris , Karimi Gholamreza 
Published: June 2021

SummaryHardware implementations of spiking neural networks, which are known as neuromorphic architectures, provide an explicit understanding of brain performance. As a result, biological features of the brain may well inspire the next generation of computers and electronic systems used in such areas as signal processing, image processing, function approximation, and pattern recognition. Approximating nonlinear functions has many uses in computer science and applied mathematics. The sigmoid is the most universal activation function in neural networks by which the relationship between biological and artificial neurons is defined. It is a suitable option for predicting the probability of anything from 0 to 1 as output. In this paper, a spiking neural network using Izhikevich neurons and a gradient descent learning algorithm are propounded to approximate the sigmoid and other nonlinear functions. The flexibility of the spiking network is demonstrated by showing the average relative errors in the approximation process. A time‐ and cost‐efficient digital neuromorphic implementation on the base of on‐chip learning method for approximating the sigmoid function is also discussed. The paper reports the results of the hardware synthesis and the spiking network's physical implementation on a field‐programmable gate array. The maximum frequency and throughput of the implemented network were 83.209 MHz and 9.86 Mb/s, respectively.
An active parallel power decoupling circuit with a dual loop control scheme for micro‐inverters
Authors: Rezaei Mohammad Hossein , Akhbari Mahdi 
Published: June 2021

AbstractAn important challenge in single‐stage single‐phase micro‐inverters is reducing required capacitance by various active power decoupling (APD) techniques in order to use film capacitors with a longer lifetime instead of electrolytic capacitors. In this paper, a photovoltaic (PV)‐side parallel APD circuit based on a bidirectional flyback converter is proposed. This topology is able to increase the average and ripple voltages for the capacitor due to having a transformer and thus can reduce the required capacitance. In the control scheme, dual control loops on the main and decoupling circuits manage the micro‐inverter operation. The primary control loop is based on the instantaneous active and reactive power theory and a proportional resonant (PR) controller that is responsible for delivering the PV panel energy to the grid. The secondary control loop regulates the pulsation power on the dc‐link capacitor through the PR controller. Simulation results demonstrated that the proposed APD circuit and the control method could properly damp the pulsation power in the normal and reference tracking operations. Furthermore, the good robustness of the micro‐inverter was confirmed in shutdown and start‐up. Finally, the experimental results with a 180‐W single‐phase micro‐inverter prototype are presented, which validates the advantages of the proposed configuration.
Synthesis and evaluation of 2‐(4‐[4‐acetylpiperazine‐1‐carbonyl] phenyl)‐1H‐benzo[d]imidazole‐4‐carboxamide derivatives as potential PARP‐1 inhibitors and preliminary study on structure‐activity relationship
Authors: Chen Miaojia , Huang Honglin , Wu Kaiyue , Liu Yunfan , Jiang Lizhi , Li Yang , Tang Guotao , Peng Junmei , Cao Xuan 
Published: June 2021

AbstractAlthough 1H‐benzo[d]imidazole‐4‐carboxamide derivatives have been explored for a long time, the structure–activity relationship of the substituents in the hydrophobic pocket (AD binding sites) has not thoroughly discovered. Here in, a series of 2‐(4‐[4‐acetylpiperazine‐1‐carbonyl]phenyl)‐1H‐benzo[d]imidazole‐4‐carboxamide derivatives have been designed, synthesized, and successful characterization as novel and effective poly ADP‐ribose polymerases (PARP)‐1 inhibitors to improve the structure–activity relationships about the substituents in the hydrophobic pocket. These derivatives were evaluated for their PARP‐1 inhibitory activity and cellular inhibitory against BRCA‐1 deficient cells (MDA‐MB‐436) and wild cells (MCF‐7) using PARP kit assay and MTT method. The results indicated that compared with other heterocyclic compounds, furan ring‐substituted derivatives 14n‐14q showed better PARP‐1 inhibitory activity. Among this derivatives, compound 14p displayed the strongest inhibitory effects on PARP‐1 enzyme (IC50 = 0.023 μM), which was close to that of Olaparib. 14p (IC50 = 43.56 ± 0.69 μM) and 14q (IC50 = 36.69 ± 0.83 μM) displayed good antiproliferation activity on MDA‐MB‐436 cells and inactivity on MCF‐7 cells, indicating that 14p and 14q have high selectivity and targeting. The molecular docking method was used to explore the binding mode of compound 14p and PARP‐1, and implied that the formation of hydrogen bond was essential for PARP‐1 inhibition activities. This study also showed that in the hydrophobic pocket (AD binding sites), the introduction of strong electronegative groups (furan ring, e.g.) or halogen atoms in the side chain of benzimidazole might improve its inhibitory activity and this strategy could be applied in further research.
Cooperation and opportunism in Galapagos sea lion hunting for shoaling fish
Authors: De Roy Tui , Espinoza Eduardo R. , Trillmich Fritz 
Published: June 2021

AbstractFor predators, cooperation can decrease the cost of hunting and potentially augment the benefits. It can also make prey accessible that a single predator could not catch. The degree of cooperation varies substantially and may range from common attraction to a productive food source to true cooperation involving communication and complementary action by the individuals involved. We here describe cooperative hunting of Galapagos sea lions (Zalophus wollebaeki) for Amberstripe scad (Decapterus muroadsi), a schooling, fast swimming semipelagic fish. A group of 6–10 sea lions, usually females only, drove scad over at least 600–800 m from open water into a cove where, in successful hunts, they drove them ashore. Frequently, these “core hunters” were joined toward the final stages of the hunt by another set of opportunistic sea lions from a local colony at that beach. The “core hunters” did not belong to that colony and apparently were together coming toward the area specifically for the scad hunt. Based on the observation of 40 such hunts from 2016 to 2020, it became evident that the females performed complementary actions in driving the scad toward the cove. No specialization of roles in the hunt was observed. All “core hunters” and also opportunistically joining sea lions from the cove shared the scad by randomly picking up a few of the 25–300 (mean 100) stranded fish as did scrounging brown pelicans. In one of these hunts, four individual sea lions were observed to consume 7–8 fish each in 25 s. We conclude that the core hunters must communicate about a goal that is not present to achieve joint hunting but presently cannot say how they do so. This is a surprising achievement for a species that usually hunts singly and in which joint hunting plays no known role in the evolution of its sociality.
Water depth influences algal distribution and productivity in shallow agricultural lakes
Authors: Henderson Kate A. , Murdock Justin N. , Lizotte Richard E. 
Published: June 2021

AbstractAgricultural activity can alter water quality and quantity resulting in lakes facing increasing interactive stressors including eutrophication, suspended sediment and water withdrawal. This study examined the relationships between water depth, water quality and algae in shallow agricultural lakes in the lower Mississippi River Basin (LMRB) to assess how lake depth influences algal structure and function, focusing on factors that typically regulate growth, that is, light, temperature and nutrients. Lake water and sediment cores were collected in shallow (mean = 0.8 m) and deep (mean = 1.7 m) locations in three lakes seasonally for 1 year. Additionally, interactive effects of light and temperature on algal growth were investigated through a laboratory experiment to determine the relative importance of each in regulating algal biomass and net oxygen production. In these shallow, turbid, eutrophic lakes, deeper water had lower nutrient concentrations and temperature across all seasons and clearer water in the summer. Shallow areas had more phytoplankton and periphyton. Water temperature had a stronger correlation than light with both phytoplankton and periphyton biomass. Algal biomass generally decreased with increasing water temperature, but biomass was better predicted by increasing nitrogen availability, and productivity declined with greater phosphorus availability. Water depth was therefore likely influencing different locations of the same lake towards different algal stable states. Mitigating excess algal production is an important goal towards limiting hypoxic conditions in the LMRB, and increasing water storage could help moderate temperature, nutrients and turbidity effects that contribute to algal blooms in lakes receiving agricultural runoff.
Ligand Effects in Carbon−Boron Coupling Processes Mediated by σ‐BH Platinum Complexes
Authors: Ríos Pablo , Fernández‐de‐Córdova Francisco José , Borge Javier , Curado Natalia , Lledós Agustí , Conejero Salvador 
Published: June 2021

AbstractThe reaction of tri‐coordinated boranes (derived from dioxaborolanes and diazaborolanes) with cyclometalated low‐electron count platinum complexes [Pt(NHC’)(NHC)][BArF] (NHC=ItBuiPr, IMes, IMes*) led, at low temperature, to the formation of the corresponding σ‐BH species. Some of these species have been characterized by X‐Ray diffraction methods showing a rare η1‐coordination mode. These compounds are thermally unstable and undergo a carbon‐boron coupling process whose reversibility depends on the NHC ligand. DFT calculations indicate that the energy barriers required for C−B bond formation events (together with Pt−H bonds) are lower than the competitive reactions leading to C−H bond formation (and Pt−B bonds). However, the C−B coupling products appear to be formed under kinetic control with ItBuiPr ligands, whereas the relative low energy barrier leading to C−H bond formation is sufficiently low to form the thermodynamically more stable platinum boryl complexes at rt. The latter energy barrier is, nevertheless, too high for the systems bearing IMes and IMes* ligands.
Comparison of two storage units for a sustainable off‐grid climate refuge shelter
Authors: Niaz Fariha , AlShafi Manal , Bicer Yusuf 
Published: June 2021

AbstractConsidering the broad range of applications, efficient retrieval and storing electrical energy methods are still challenging. Besides the load variations, the ever‐increasing intermittent renewable energy penetration into the grid system has witnessed the system complexities. In off‐grid applications, energy storage can balance electricity consumption and electricity generation to avoid voltage and frequency deviations. This research paper focuses on the energy management of an off‐grid climate refuge system used for hot and arid locations with a system comparison for two routes of different storage techniques, namely flywheels and a lithium‐ion battery. The proposed system can generate its power from photovoltaics and provide cooling and other auxiliaries through vapor compression cycle and water misting units with an operation of about 16 hours (ie, from 7:00 am to 11:00 pm) on the weekdays and 12 hours on the weekends. A comparison of levelized costs is conducted for the evaluation using HOMER software. The annual energy production by solar photovoltaics for the proposed system is 20 MWh, and the annual consumption is 16 MWh. The photovoltaic‐battery storage system has shown the lowest cost of electricity, corresponding to 0.761 $/kWh, and net present cost of $66 238 and is optimum in all sensitivity analysis cases.
Assessing the effects of inulin‐type fructan intake on body weight, blood glucose, and lipid profile: A systematic review and meta‐analysis of randomized controlled trials
Authors: Li Liangkui , Li Peng , Xu Li 
Published: June 2021

AbstractInulin‐type fructan (ITF) intake has been suggested to alleviate several features of metabolic syndrome including obesity, diabetes, and hyperlipidemia; yet, results from the human trials remained inconsistent. We aimed to systematically evaluate the effects of ITF intake on body weight, glucose homeostasis, and lipid profile on human subjects with different health status, including healthy, overweight and obese, prediabetes and diabetes, and hyperlipidemia. Weighted mean differences (WMDs) between ITF and control groups were calculated by a random‐effects model. A total of 33 randomized controlled human trials were included. Significant effect of ITF intake was only observed in the diabetics, but not in the other subject groups. Specifically, ITF intervention significantly decreased the WMD of blood glucose (−0.42 mmol/L; 95% CI: −0.71, −0.14; p = .004), total cholesterol (−0.46 mmol/L; 95% CI: −0.75, −0.17; p = .002), and triglycerides (TAG) (−0.21 mmol/L; 95% CI: −0.37, −0.05; p = .01) compared with the control. The stability of these favorable effects of ITF on diabetics was confirmed by sensitivity analysis. Also, ITF tends to lower LDL cholesterol (p = .084). But body weight and blood insulin were not affected by ITF intake. It should be noted that blood glucose, total cholesterol, and LDL cholesterol exhibited high unexplained heterogeneity. In conclusion, ITF intake lowers blood glucose, total cholesterol, and TAG in the people with diabetes, and they may benefit from addition of inulin into their diets, but the underlying mechanisms responsible for these effects are inconclusive.
Implications of measurement metrics on soil freezing curves: A simulation of freeze–thaw hysteresis
Authors: Pardo Lara Renato , Berg Aaron A. , Warland Jon , Parkin Gary 
Published: June 2021

AbstractSoil freeze–thaw events have important implications for water resources, flood risk, land productivity, and climate change. A property of these phenomena is the relationship between unfrozen water content and sub‐freezing temperature, known as the soil freezing characteristic curve (SFC). It is documented that this relationship exhibits hysteretic behaviour when frozen soil thaws, leading to the definition of the soil thawing characteristic curve (STC). Although explanations have been given for SFC/STC hysteresis, the effect that ‘scale’ – particularly ‘measurement scale’ – may have on these curves has received little attention. The most commonly used measurement scale metric is the ‘support’, which is the spatial (or temporal) unit within which the measured variable is integrated or soil volume sampled. We show (a) measurement support can influence the range and shape of the SFC and (b) hysteresis can be attributed, in part, to the support and location of the measurements comprising the SFC/STC. We simulated lab measured temperature, volumetric water content (VWC), and permittivity from soil samples undergoing freeze–thaw transitions using Hydrus‐1D and a modified Dobson permittivity model. To assess the effect of measurement support and location on SFC/STC, we masked the simulated temperature and VWC/permittivity extent to match the instrument's support and location. By creating a detailed simulation of the intra‐ and inter‐support variability associated with the penetration of a freezing front, we demonstrate how measurement support and location can influence the temperature range over which water freezing events are captured. We show it is possible to simulate hysteresis in homogenous media with purely geometric considerations, suggesting that SFC/STC hysteresis may be more of an apparent phenomenon than mechanistically real. Lastly, we develop an understanding of how the location and support of soil temperature and VWC/permittivity measurements influence the temperature range over which water freezing events are captured.
An accurate and noninvasive skin cancer screening based on imaging technique
Authors: Rajput Gunjan , Agrawal Shashank , Raut Gopal , Vishvakarma Santosh Kumar 
Published: June 2021

AbstractIn the last decade, the public health problem is the primary consciousness worldwide, and cancer is especially the central issue. Further, skin cancer comes in the top‐3 of the world's most common cancer. We have proposed an efficient convolutional neural network (CNN) model that identifies skin cancer problems accurately. Although dataset HAM10K is used for the classification problem, its samples for each class are highly imbalanced and therefore are accountable for lower training accuracy. The AlexNet model is customized for the HAM10K data classification to address this problem. In addition, this work has presented an activation function that overcomes the vanishing gradient problem, and it is verified using the used dataset at multiple benchmark architectures. The results show better accuracy compared to the state‐of‐the‐art activation function. Our customized CNN architecture with the proposed activation function has 98.20% accuracy for HAM10K, which is better than any other state‐of‐the‐art models currently present. Further, precision, recall, and F‐score results are also improved, which are also 98.20%.
Optimal control of a crop irrigation model under water scarcity
Authors: Boumaza Kenza , Kalboussi Nesrine , Rapaport Alain , Roux Sébastien , Sinfort Carole 
Published: June 2021

AbstractWe consider a simple crop irrigation model and study the optimal control which consists of maximizing the biomass production at harvesting time. A specificity of this work is to impose a quota on the water used for irrigation, in a context of limited resources. The model is written as a 2d non‐autonomous dynamical system with a state constraint, and a non‐smooth right member given by threshold‐based soil and crop water stress functions. We show that when the water quota is below the threshold giving the largest possible production, the optimal strategy consists of irrigating once. We then show that the optimal solution can have one or several singular arcs, and therefore be better than simple bang‐bang controls, as commonly used. The gains over the best bang‐bang controls are illustrated on numerical simulations. These new feedback controls that we obtain are a promising first step towards the concrete application of control theory to the problem of optimal irrigation scheduling under water scarcity.
Output feedback fuzzy control of nonlinear dynamic systems: Event‐triggered case
Authors: Su Xiaojie , Chen Qianqian , Jiao Chunting , Dai Xin 
Published: June 2021

AbstractThe event‐triggered output feedback controller design problem is investigated in this article for a class of discrete‐time Takagi–Sugeno fuzzy systems. We focus on constructing a closed‐loop system by considering the event generator communication mechanism, interval time‐varying delays, and packet dropouts. Under this newly established system, a less conservative stability condition is obtained using the Wirtinger‐based inequality and reciprocally convex approach, which guarantees that the corresponding augmented system is asymptotically stable in the mean‐squared sense with a prespecified – performance. The solution of the designed output feedback controller parameters can then be obtained by variable substitution method and by conversion of the controller parameters. Finally, two examples are presented to demonstrate the effectiveness of the proposed controller design technique.
Electrochemical Installation of CFH2−, CF2H−, CF3−, and Perfluoroalkyl Groups into Small Organic Molecules
Authors: Kisukuri Camila M. , Fernandes Vitor A. , Delgado José A. C. , Häring Andreas P. , Paixão Márcio W. , Waldvogel Siegfried R. 
Published: June 2021

AbstractElectrosynthesis can be considered a powerful and sustainable methodology for the synthesis of small organic molecules. Due to its intrinsic ability to generate highly reactive species under mild conditions by anodic oxidation or cathodic reduction, electrosynthesis is particularly interesting for otherwise challenging transformations. One such challenge is the installation of fluorinated alkyl groups, which has gained significant attention in medicinal chemistry and material science due to their unique physicochemical features. Unsurprisingly, several electrochemical fluoroalkylation methods have been established. In this review, we survey recent developments and established methods in the field of electrochemical mono‐, di‐, and trifluoromethylation, and perfluoroalkylation of small organic molecules.
Atractylodin attenuates the expression of MUC5AC and extracellular matrix in lipopolysaccharide‐induced airway inflammation by inhibiting the NF‐κB pathway
Authors: Dong Yanpeng , Zhang Xiao , Yao Chuan , Xu Rui , Tian Xiaohong 
Published: June 2021

AbstractThis study aimed to explore the effects of atractylodin (ATR) on lipopolysaccharide (LPS)‐induced inflammatory response in human airway epithelial cells. The cytotoxicity was assessed by CCK‐8 assay. The mRNA expression and concentration of interleukin (IL)‐6, IL‐8, and mucin 5AC (MUC5AC) were measured by qRT‐PCR and ELISA, respectively. Western blotting was performed to determine protein expression. We found that LPS stimulation increased the mRNA expression and concentrations of IL‐6, IL‐8, and MUC5AC, as well as the expression of Col‐I and FN in 16HBE cells, but this effect of LPS was attenuated by ATR treatment. Mechanistically, ATR suppressed LPS‐induced activation of the NF‐κB pathway in 16HBE cells. Moreover, ATR repressed ovalbumin‐induced airway inflammation and NF‐kB pathway in mice. In conclusion, ATR attenuated the expression of MUC5AC and ECM in LPS‐induced airway inflammation by inhibiting the NF‐κB pathway.
Pitfalls and advances in morphometric sexing: insights from the Adélie penguin Pygoscelis adeliae
Authors: Fattorini Niccolò , Olmastroni Silvia 
Published: June 2021

AbstractSexing weakly/criptically dimorphic birds requires invasive techniques or molecular analysis. Alternatively, sexing can be based upon morphometric analysis, which remains invaluable in remote field conditions such as Polar regions. Nevertheless, discriminatory power may be affected by methodological issues hampering comparison between/within studies, e.g. considering alternative analytical techniques or measurements taken by different researchers. We investigated the sexing potential of bill length, bill depth and body mass in adult Adélie penguinsPygoscelis adeliaeof known sex. We performed discriminant analysis on a large dataset of measurements (237 males; 264 females) taken from penguins marked between 1994 and 2001, at Edmonson Point (Ross Sea, Antarctica). In a second step, we accounted for measurements collected by different researchers through permuted discriminant analysis. We found moderate support for sex discrimination through bill measurements (77%). Considering body mass did not improve classification power substantially (78.2%), possibly because of confounding inter/intra-annual oscillations in body condition. Discriminant rate decreased when controlling the researcher effect (72.7% and 71.4%, respectively). Results were also confirmed by logistic (mixed) models. Simulations showed that reduction in sample size markedly increased uncertainty in classification power. Differences with previous studies achieving a slightly greater classification power for sexing Adélie penguins through morphometrics could be related to (i) our higher sample size and/or (ii) geographical, population-specific differences, e.g. lower degree of sexual dimorphism. Our work emphasises key-factors influencing performance of morphometric sexing in avian species, advocating population-specific validation with large sample size as well as the necessity to account for the researcher effect prior to apply morphometric sexing.