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Nitrite pre-treatment of dewatered sludge for microbial fuel cell application

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Journal of Environmental Sciences 2019年第3期31卷 148-155页

作者： Abdul Rasyid Ruslan vel Murugan Vadivelu School of Chemical Engineering Universiti Sains MalaysiaEngineering Campus

The effect of pre-treatment of dewatered sludge using different nitrite concentrations and p H for microbial fuel cell(MFC) application was investigated. The results show that the addition of nitrite was feasible to increase the solubilization rate of the sludge and may reduce mass transfer limitation at the anode. This helped the MFC to reach higher voltage and to generate more power. The higher free nitrous acid(FNA) concentration under the acidic condition helped to increase sludge solubilization. However, under an alkaline condition, during which the FNA concentration was relatively low, the solubilization of the sludge was higher. The highest voltage and power density produced was 390 mV and 153 mW/m^2, respectively, with the addition of nitrite at 100 mg-N/L and pH 9. Furthermore,it was found that elevated levels of FNA could inhibit electrogenic bacteria thus reducing power generation.

关键词： Dewatered sludge Nitrite pre-treatment Free nitrous acid Microbial fuel cell Electricity generation

Regeneration of neurotransmission transcriptome in a model of epileptic encephalopathy after antiinflammatory treatment

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Neural Regeneration Research 2018年第10期13卷 1715-1718页

作者： Dumitru A.Iacobas Libor velísek Center for Computational Systems Biology Prairie View AM University Prairie View TX USA D.P.Purpura Department of Neuroscience Albert Einstein College of MedicineNew York NY USA Department of Cell Biology & Anatomy New York Medical CollegeValhalla NY USA Department of Neurology New York Medical CollegeValhalla NY USA Department of Pediatrics New York Medical CollegeValhalla NY USA

Inflammation is an established etiopathogenesis factor of infantile spasms（IS）, a therapy-resistant epileptic syndrome of infancy. We investigated the IS-associated transcriptomic alterations of neurotransmission in rat hypothalamic arcuate nucleus, how they are corrected by antiinflamatory treatments and whether there are sex differences. IS was triggered by repeated intraperitoneal administration of N-methyl-D-aspartic acid following anti-inflammatory treatment（adreno-cortico-tropic-hormone（ACTH） or PMX53）or normal saline vehicle to prenatally exposed to betamethasone young rats. We found that treatments with both ACTH and PMX53 resulted in substantial recovery of the genomic fabrics of all types of synaptic transmission altered by IS. While ACTH represents the first line of treatment for IS, the even higher efficiency of PMX53（an antagonist of the complement C5 a receptor） in restoring the normal transcriptome was not expected. In addition to the childhood epilepsy, the recovery of the neurotransmission genomic fabrics by PMX53 also gives hope for the autism spectrum disorders that share a high comorbidity with IS. Our results revealed significant sex dichotomy in both IS-associated transcriptomic alterations（males more affected） and in the efficiency of PMX53 anti-inflammatory treatment（better for males）. Our data further suggest that anti-inflammatory treatments correcting alterations in the inflammatory transcriptome may become successful therapies for refractory epilepsies.

关键词： adreno-cortico-tropic-hormone autism cholinergic transmission hypothalamus infantile spasms microarrays PMX53 sex differences

Tropical Cyclones in Nicaragua:Historical Impact and Contemporary Exposure to Disaster Risk

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International Journal of Disaster Risk Science 2024年第4期15卷 579-593页

作者： Gema velásquez‑Espinoza Irasema Alcántara‑Ayala Faculty of Sciences and Engineering National Autonomous University of Nicaragua14172 Unan-ManaguaNicaragua Postgraduate Programme in Geography National Autonomous University of Mexico(UNAM)04510 Mexico CityMexico Institute of Geography National Autonomous University of Mexico(UNAM)04510 Mexico CityMexico

In tropical regions such as Nicaragua, the population's vulnerability to hazards has escalated in recent decades. This increase in vulnerability has led to a surge in disasters, particularly those triggered by intense hurricanes. The implications at the national level are still poorly understood. The aim of this article has, therefore, been two-fold. First, to present a historical review of the direct effects of tropical cyclones on society in Nicaragua from 1852 to 2020. Second, to analyze the statistical probabilities of future hurricane-spawned high winds over Nicaragua. Data on cyclones hitting Nicaragua's coasts were collected, including direct effects, wind speed, pressure, category, direction, and time of landfall. A database was created to classify intensity based on wind speed and frequency. Between 1852 and 2020, Nicaragua experienced 58 tropical cyclones with varying degrees of intensity between September and November. The trajectories of six past hurricanes were considered here regarding the areas that might have been under potential threat. Three zones of influence were delimited along each trajectory according to three wind intensities and the trajectory of these hurricanes. The consequent exposure of each Nicaraguan department and autonomous region was established. The findings are essential to delimitating priority areas for attention regarding the likely impact of tropical cyclones, mainly category 4 and 5 hurricanes. Public officials and the general public can use these data to identify the pressing need for enhanced strategies to mitigate disaster risk and avoid potential disasters.

关键词： Exposure Historical impact Hurricanes Nicaragua Tropical cyclones Vulnerability

Novel kinetic model for the simulation analysis of the butanol productivity of Clostridium acetobutylicum ATCC 824 under different reactor configurations

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Chinese Journal of Chemical Engineering 2018年第4期26卷 812-821页

作者： Hugo I.velázquez-Sánchez Ricardo Aguilar-López Center of Research and Advances Studies of the National Polytechnic Institute (CINVESTAV) Biotechnology and Bioengineering DepartmentAv. National Polytechnic Institute 2508 Col. San Pedro Zacatenco

Acetone–butanol–ethanol(ABE)fermentation process can be exploited for the generation of butanol as biofuel,however it does need to overcome its low volumetric solvent productivity before it can commercially compete with fossil fuel *** this regard,mathematical modelling and simulation analysis are tools that can serve as the base for process engineering development of biological *** this work,a novel phenomenological kinetic model of Clostridium acetobutylicum ATCC 824 was considered as a benchmark system to evaluate the behaviour of an ABE fermentation under different process configurations using both free and immobilized cells:single stage batch operation,fed-batch,single stage Continuous Stirred Tank Reactor(CSTR)and multistage CSTRs with and without biomass *** proposed model achieved a linear correlation index r^2=0.9952 and r^2=0.9710 over experimental data for free and immobilized cells *** predicted maximum butanol concentration and productivity obtained were 13.08 g·L^(-1)and 1.9620 g·L^(-1)·h^(-1)respectively,which represents an increase of 1.01%and 990%versus the currently developed industrial scale process reported currently into the *** results provide a reliable platform for the design and optimization of the ABE fermentation system and showcase the adequate predictive nature of the proposed model.

关键词： Biofuels Butanol Clostridium acetobutylicum Mathematical modelling Process configurations

Sailboat navigation control system based on spiking neural networks

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Control Theory and Technology 2023年第4期21卷 489-504页

作者： Nelson Santiago Giraldo Sebastián Isaza Ricardo Andrés velásquez Department of Electronics and Telecommunications Engineering University of Antioquia67 stMedellin050010AntioquiaColombia

In this paper,we presented the development of a navigation control system for a sailboat based on spiking neural networks(SNN).Our inspiration for this choice of network lies in their potential to achieve fast and low-energy computing on specialized *** train our system,we use the modulated spike time-dependent plasticity reinforcement learning rule and a simulation environment based on the BindsNET library and USVSim *** objective was to develop a spiking neural network-based control systems that can learn policies allowing sailboats to navigate between two points by following a straight line or performing tacking and gybing strategies,depending on the sailing scenario *** presented the mathematical definition of the problem,the operation scheme of the simulation environment,the spiking neural network controllers,and the control strategy *** a result,we obtained 425 SNN-based controllers that completed the proposed navigation task,indicating that the simulation environment and the implemented control strategy work ***,we compare the behavior of our best controller with other algorithms and present some possible strategies to improve its performance.

关键词： Sailboat Control Spiking neuron Reinforcement learning BindsNet USVSim

Improved Interleaved Single-Ended Primary Inductor-Converter forSingle-Phase Grid-Connected System

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Intelligent Automation & Soft Computing 2023年第3期35卷 3459-3478页

作者： T.J.Thomas Thangam K.Muthu vel Noorul Islam Centre for Higher Education Nagarkovil629180TamilnaduIndia

The generation of electricity based on renewable energy sources,parti-cularly Photovoltaic(PV)system has been greatly increased and it is simply insti-gated for both domestic and commercial *** power generated from the PV system is erratic and hence there is a need for an efﬁcient converter to perform the extraction of maximum *** improved interleaved Single-ended Primary Inductor-Converter(SEPIC)converter is employed in proposed work to extricate most of power from renewable *** proposed converter minimizes ripples,reduces electromagnetic interference due toﬁlter elements and the contin-uous input current improves the power output of PV panel.A Crow Search Algo-rithm(CSA)based Proportional Integral(PI)controller is utilized for controlling the converter switches effectively by optimizing the parameters of PI *** optimized PI controller reduces ripples present in Direct Current(DC)vol-tage,maintains constant voltage at proposed converter output and reduces over-shoots with minimum settling and rise *** voltage is given to single phase grid via 1�Voltage Source Inverter(VSI).The command pulses of 1�VSI are produced by simple PI *** response of the proposed converter is thus improved with less input *** implementing CSA based PI the efﬁciency of proposed converter obtained is 96%and the Total Harmonic Distor-tion(THD)is found to be 2:4%.The dynamics and closed loop operation is designed and modeled using MATLAB Simulink tool and its behavior is performed.

关键词： Improved interleaved DC-DC SEPIC converter crow search algorithm PI controller voltage source inverter PV array single phase grid

Alternative beneficiation of tantalite and removal of radioactive oxides from Ethiopian Kenticha pegmatite–spodumene ores

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International Journal of Minerals,Metallurgy and Materials 2017年第7期24卷 727-735页

作者： Berhe Goitom Gebreyohannes velázquez del Rosario Alberto Abubeker Yimam Girma Woldetinsae Bogale Tadesse School of Materials Science and Engineering Jimma Institute of Technology Jimma University P.O. Box 378 Jimma Ethiopia Chemistry Department College of Natural and Computational Science Mekelle University P.O. Box 823 Mekelle Ethiopia School of Chemical and Bio Engineering AAiT Addis Ababa University P.O. Box 1176 Addis Ababa Ethiopia Research and Development Directorate Federal Democratic Republic of Ethiopia Ministry of Mines Petroleum and Natural Gas P.O. Box 486 Addis Ababa Ethiopia Department of Mining Engineering and Metallurgical Engineering Western Australian School of Mines Curtin University Egan St Kalgoorlie WA 6430 Australia

The beneficiation methods for Ethiopian Kenticha pegmatite–spodumene ores were assessed through mineralogical and quantitative analyses with X-ray diffraction（XRD） and energy-dispersive X-ray fluorescence（EDXRF）. The tantalite in the upper zone of the Kenticha pegmatite–spodumene deposit is 58.7wt% higher than that in the inner zone. XRD analysis revealed that the upper zone is dominated by manganocolumbite, whereas the inner zone is predominantly tantalite-Mn. Repeated cleaning and beneficiation of the upper-zone ore resulted in concentrate compositions of 57.34wt% of Ta_2O_5 and 5.41wt% of Nb_2O_5. Washing the tantalite concentrates using 1vol% KOH and 1 M H_2SO_4 led to the removal of thorium and uranium radioactive oxides from the concentrate. The findings of this study suggest that the beneficiation and alkaline washing of Kenticha pegmatite–spodumene ores produce a high-grade export-quality tantalite concentrate with negligible radioactive oxides.

关键词： beneficiation manganocolumbite pegmatite-spodumene radioactive oxides tantalite

The Limit Case of a Domination Property

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Acta Mathematica Sinica,English Series 2012年第3期28卷 463-468页

作者： Magdalena LEMANSKA Juan A. RODRíGUEZ-velZQUEZ Ismael G. YERO Department of Technical Physics and Applied Mathematics Gdańsk University of Technology Departament d’Enginyeria Informàtica i Matemàtiques Universitat Rovira i Virgili Departament d'Enginyeria Informàtica i Matemàtiques Universitat Rovira i Virgili

The domination number γ,（G） of a connected graph G of order n is bounded below by

关键词： Dominating set domination number

Reporter gene systems for the identification and characterization of cancer stem cells

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World Journal of Stem Cells 2021年第7期13卷 861-876页

作者： NohemíSalinas-Jazmín Arely Rosas-Cruz Marco vel.sco-velázquez Department of Pharmacology School of MedicineUniversidad Nacional Autónoma de MéxicoMexico City 04510Mexico

Cancer stem cells(CSCs)are tumor cells that share functional characteristics with normal and embryonic stem *** have increased tumor-initiating capacity and metastatic potential and lower sensitivity to chemo-and radiotherapy,with important roles in tumor progression and the response to ***,a current goal of cancer research is to eliminate CSCs,necessitating an adequate phenotypic and functional characterization of *** have been developed to identify,enrich,and track CSCs,many of which distinguish CSCs by evaluating the expression of surface markers,the initiation of specific signaling pathways,and the activation of master transcription factors that control stemness in normal *** review and discuss the use of reporter gene systems for identifying *** that are under the control of aldehyde dehydrogenase 1A1,CD133,Notch,Nanog homeobox,Sex-determining region Y-box 2,and POU class 5 homeobox can be used to identify CSCs in many tumor types,track cells in real time,and screen for ***,reporter gene systems,in combination with in vitro and in vivo functional assays,can assess changes in the CSCs *** present relevant examples of these systems in the evaluation of experimental CSCs-targeting therapeutics,demonstrating their value in CSCs research.

关键词： Cancer Gene reporter systems Cancer stem cells Pluripotency transcription factors Anticancer drugs Preclinical analysis Cancer stem cells marker